COMPARATIVE ANATOMY

15 Y

C. TIL v. SIEBOLD and H. STANNIUS.

TRANSLATED FROM THE GERMAN,

AND

EDITED WITH NOTES AND ADDITIONS

RECORDING THE

RECENT PROGRESS OF THE SCIENCE,

B Y

WALDO I. BURNETT, M.D.

VOLUME I.

LONDON:

TRUBNER & CO.,

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mm

ANATOMY

OF THE

INVERTEBRATA.

Ii V

C. TIL v. SIEBOLD.

2T o

MY ESTEEMED FRIEND,

LOUIS AOASSIZ,

PROFESSOR OF ZOOLOGY, &0.,

I N

fjarfrarb (ftiribcrsitg,

WHOSE WELL-KNOWN RELATIONS TO COMPARATIVE ANATOMY REQUIRE
NO MENTION HERE, AND WHOSE SPLENDID GENIUS HAS DONE SO MUCH TO AWAKEN,
IN THIS COUNTRY ESPECIALLY,

•» A LIVELY INTEREST IN OBJECTS OF NATURAL HISTORY,

1 |nsrnlif tfris ttoUuiu,

WITH ADMIRATION AND SINCERE GRATITUDE.

WALDO L BURNETT.

1*

NOTICE OF THE TRANSLATOR AND EDITOR

In issuing an English translation of the Lelirbuch der ver-
gleichenden Anatomie of Von Siebold and Stannius, any
formal account of the work is quite unnecessary. To all Anato-
mists it is a treatise already well and favorably known, and it has
justly been regarded as the most complete and comprehensive work
of its kind now extant in any language. The high position and
distinguished reputation of its authors have been fully sustained by
this portion of their labors.

But there are several features in this work which should be men-
tioned, since by them it is favorably distinguished from all other
treatises of the kind that have preceded it.

In the text will be found a lucid yet succinct exposition of the
anatomical structure of organs, arranged as far as practicable under
distinct types. The details on which this typical summary is based,
are comprised in notes which are as remarkable for their erudition
as for their copiousness ; indeed, the utmost care has been taken in
the literature of the various subjects treated, and the student will
here find the most reliable and at the same time the fullest refer-
ence to the bibliography of nearly every subject in Comparative
Anatomy. In this way, the work as a whole furnishes a complete
dictionary of the science, and will prove invaluable even as a work
of suggestion and reference, to those who would pursue any special
line of inquiry and research in this department.

It may be truly said that the Microscope lies at the foundation of
all our best knowledge of anatomy, and especially that of the Inverte-
brata. This is the case, not only on account of the small size of most
of the animals, but because, as Von Siebold has said in his preface,
the anatomy of these lower forms is scarcely reliable unless based
upon histological investigations.

VIII

NOTICE OF THE TRANSLATOR AND EDITOR.

Hence, that part of the work treating of the anatomy of the
Invertebrata, by Von Siebold, is rich in the results of microscopi-
cal researches ; and their value in the elucidation of the subject
will be readily appreciated. This plan of procedure has not the
same urgency with the higher animals, where the character of an
organ or part can generally be ascertained from its position, &c. ; and,
in the second part of the work, on the Anatomy of the Vertebrata,
by Stannius, details of microscopical structure are comparatively
little insisted upon. But, within a few years, the histological compo-
sition of organs, even though their character and function is well
known, has become of great and increasing interest ; and details of
this kind, as far as they would be understood without the aid of
figures, I have sought to add in their regular order and place.

As to the notes and additions generally, they stand by themselves
with Ed. affixed, and almost invariably refer to some point treated of
in the text or notes of the original, and for the most part relate to the
correction, confirmation, or extension of some statements there made.
These notes were drawn from all the sources accessible to me; but
from the many difficulties in the way of the early receipt of foreign
works in this country, they are not as complete a record of the recent
progress of the science as would be desifed.

As to the translation, I may say, that not being a German scholar,
but having read the German language chiefly for scientific purposes,
I trust that any inelegances of diction or idiom will be excused.
But, throughout, I have endeavored to give a faithful rendering of
the author’s meaning, and to express this in as simple and terse a
form as possible.

In conclusion, I wish to express my gratitude to my friends who
have kindly aided me in this work ; — prominent among these is Mr.
Edward Capen of this city, who has been of invaluable assistance
to me in the labor of passing the sheets of this volume through the
press; — of others, such as Professors Agassiz, Dana , Leidy , and
Wyman , their names will be found honorably recorded by their own
important labors in science, to which I have so frequently referred
in these volumes. W. I. B.

Boston, Nov. 1853.

PREFACE.

As latterly, Zootomists have given much greater attention to the
invertebrate animals than formerly ; and as, with these investigations
they have united, as much as possible, others upon the generation
and development of these animals, such a mass of material, composed,
in part, of entirely new and very remarkable facts, has accumulated,
that the manuals of Zootomy hitherto published are of a scale quite
inadequate to receive them. It is unnecessary, therefore, for me to
offer further reason for the task I have undertaken of arranging these
materials and reducing them to a systematic form. But the order
in which I have disposed them may not meet with general approval,
for, hitherto, in works of comparative anatomy, the organs, and not
the zoological classes, have served as the basis of the order pursued.

But, in the present state of Science, and at least provisionally, it
appears to me that the anatomical order should not be followed, for,
the types, which, until now, have been recognized in the develop-
mental series of the several organs, appear no longer valid and
permanent. Indeed, extended researches made upon a great number
of animals, have shown that these types, hitherto regarded as express-
ive of fundamental laws, may almost be taken as the exceptions.
Such genera as Hydra , Lumbricus , Hirudo, Unto. Astacus, &c.,
can now no longer be regarded as the representatives of certain
animal classes or orders, for their organization is far from affording
the requisite type of that of allied animals. It appears now clearly
determined that the types of the development and disposition of the
various organs of the Invertebrata are more numerous and varied
than hitherto supposed, and that, in this respect, a rule wholly differ-
ent from that of those of the Vertebrata must here be applied. But as
the numberless details which we now possess upon the organization of
the Invertebrata, have not been thoroughly worked out and system-
atized in all the orders, it is really a task too difficult to here
distinguish the rule from the exception, and the type from that which
is oidy a secondary modification.

X

PREFACE.

I have especially devoted myself to the collecting and collating as
completely as practicable, the numerous new and important facts in
the organization of the invertebrate animals, which have as yet been
developed. And as occasion presented, I have verified with my own
eyes the particular results ; and when I have been obliged to refer
to the discoveries and observations of others, I have cited exactly their
works.

I could not exclude Embryology and Histology from this work, for,
in these branches, often lies our only means not only to ascertain the
true nature of many larval forms among the lower animals, but also
to arrive at the correct interpretation of many organs which, in form,
position, and arrangements, have no analogues among the higher
animal forms. It is only by the aid of Histology that we are able to
show that this or that organ is a branchia, a liver, a kidney, an
ovary, or a testicle; while, in the Vertebrata, which are organized
after a few principal types, the signification of most of the organs
can usually be easily determined by their position and connection.

In order to avoid long descriptions, I have, when practicable, re-
ferred to plates and figures ; but in so doing I have always endeavored
to cite the good and original representations, for I am convinced that
many figures which are transferred from one book to another, become,
at last, so changed as to be quite dissimilar to the original.

The elaboration of this work having been commenced in 1845, but
its completion having been delayed by my change of residence from
Erlangen to Freiburg, and partly by a pretty long sojourn of mine on
the Adriatic Sea, I have been unable to use the important works
which have been published during the last few years, except in the
form of a Supplement [additional notes] which will serve to com-
plete, to confirm, or to rectify what has been advanced in the body
of the work.

I take this opportunity to publicly express my gratitude to A.
Kolliker, H. Koch , A. Krohn, C. Vogt , and H. Stannius, for the
friendly and important aid they have rendered me in the completion
of this difficult task — not only by the transmission to me of inter-
esting and rare marine animals, but also in the communication of
important manuscripts and letters, the contents of which they have
allowed me to freely use for my work.

Freiburg (in Breisgau), Feb. 27, 1848.

C. Th. v. SIEBOLD.

TABLE OF CONTENTS.

SECTION

Classification of the Invertebrate Animals, 1

Bibliography, 2

Introductory Note to the Infusoria.

I. THE INFUSORIA AND RHIZOPODA.

Classification and Bibliography, 3-5

1. External Covering, 6

2. Muscular System, and Locomotive Organs, 7-8

3, 4. Nervous System, and Organs of Sense, 9-10

6. Digestive Apparatus 11-15

6, 7. Circulatory and Respiratory Systems, 16-18

8„ Organs of Secretion, 19

9. Organs of Reproduction, 20-23

Introductory Note to the Zoophyta.

n. THE POLYPI.

Classification and Bibliography, 24

1. Cutaneous Envelope and Skeleton, 25-28

2. Muscular System, and Organs of Locomotion, 29-32

3, 4. Nervous System, and Organs of Sense, 33-34

6. Digestive Apparatus, , 35-36

Digestive Cavity of the Anthozoa, 37

Digestive Cavity of the Bryozoa, 38

6, 7. Circulatory and Respiratory Systems, 39-41

8. Organs of Secretion, 42

9. Organs of Generation, 43-52

HI. THE ACALEPHAE.

Classification and Bibliography, 53

1. Skin and Cutaneous Skeleton 54-56

2. Muscular System, and Organs of Locomotion, 57-58

3. Nervous System, 59

4. Organs of Sense, 60

6. Digestive Apparatus, 61

6. Circulatory System, 62

7. Respiratory System, 63-64

XII

CONTENTS.

SECTION

8. Organs of Secretion, 65

9. Organs of Generation, 66-70

IV. THE ECHINODERMATA.

Classification and Bibliography, 71

1. Cutaneous Envelope and Skeleton, 72-75

2. Muscular System, and Organs of Locomotion, 76-78

3. Nervous System, 79-80

4. Organs of Sense 81

5. Digestive Apparatus 82-86

6. Circulatory System, . 87-88

7. Respiratory System, 89-93

8. Organs of Secretion, 94

9. Organs of Generation, 95-98

V. THE HELMINTHES.

Classification and Bibliography, 99

1. Cutaneous System 100-101

2. Muscular System, and Organs of Locomotion 102-103

3. Nervous System, 104

4. Organs of Sense, 105

5. Digestive Apparatus 106-109

6. Circulatory System, 110-111

7. Respiratory System, 112

8. Organs of Secretion 113

9. Organs of Generation, 114-119

VI. THE TURBELLARIA.

Classification and Bibliography, 120

1. Cutaneous System 121

2. Muscular System, and Locomotive Organs, 122

3, 4- Nervous System, and Organs of Sense, 123-124

5.. Digestive Apparatus, 125

6, 7. Circulatory and Respiratory Systems 126

8. Organs of Secretion, 127

9. Organs of Generation, 128-129

VII. THE ROTATORIA.

Classification and Bibliography, 130

1. Cutaneous System, 131

2. Muscular System, and Locomotive Organs, 132-133

3, 4. Nervous System, and Organs of Sense, 134-135

5. Digestive Apparatus 136

6, 7. Circulatory and Respiratory Systems, 137-138

8. Organs of Secretion, 139

9. Organs of Generation 140-141

VTH. THE ANNELIDES.

Classification and Bibliography, 142

1. Cutaneous System, 143

2. Muscular System, and Locomotive Organs, 144-145

CONTENTS.

XIII

SECTION

3. Nervous System 146-148

4. Organs of Sense 149-161

I. Organs of Touch, 149

II. Organs of Vision, 150

III. Organs of Hearing, • 151

5. Digestive Apparatus, 152-155

I. Organs of Deglutition and Mastication, 153

II. Intestinal Canal, 154

III. Glandular Appendages, 155

6. Circulatory System, y 156-157

7. Respiratory System, 158-160

8. Organs of Secretion, 161

9. Organs of Generation 162-169

IX. THE ACEPIIALA.

Classification and Bibliography, 170

1. Cutaneous System, 171-175

2. Muscular System, and Organs of Locomotion 176-180

3. Nervous System, 181-184

4. Organs of Sense, 185-187

6. Digestive Apparatus, 188-190

6. Circulatory System, 191-192

7. Respiratory System, 193-195

8. Organs of Secretion, . ■ 196

9. Organs of Generation 197-200

X. THE CEPHALOPIIORA.

Classification and Bibliography, 201

1. Cutaneous System, 202-203

2. Muscular System, and Organs of Locomotion, 204-205

3. Nervous System, 206-209

4. Organs of Sense, 210-212

5. Digestive Apparatus, 213-215

6. Circulatory System, 216-218

7. Respiratory System, 219-222

I. Branchiae, 220

II. Lungs 221

HI. Aquiferous System, • 222

8. Organs of Secretion, 223-224

I. Urinary Organs, 223

n. Organs of Peculiar Secretions, 224

9. Organs of Generation, 225-229

XI. THE CEPHALOPHODA.

Classification and Bibliography, 230

1. Internal Skeleton, 231-232

2. Cutaneous Envelope, 233-235

3. Muscular System, and Organs of Locomotion, 236-238

4. Nervous System, 239-242

5. Organs of Sense, 243-247

6. Digestive Apparatus, 248-250

7. Circulatory System 251-552

8. Respiratory Organs, 253-254

2

XIV

CONTENTS.

SECTION

9. Organs of Secretion, 255-256

I. Urinary Organs 255

II. Organs of Special Secretions, 256

10. Organs of Generation, 257-261

Introductory Note to the Crustacea.

XH. THE CRUSTACEA.

Classification and Bibliography, 262

1. External Envelope, and Cutaneous Skeleton, 263-266

2. Muscular System, and Oi'gans of Locomotion, 267-269

3. Nervous System, 270-273

4. Organs of Sense, 274-277

5. Digestive Apparatus, 278-281

6. Circulatory System, 282-284

7. Respiratory System, 285-287

8. Organs of Secretion, 288-289

I. Urinary Organs, 288

H. Organs of Special Secretions, 289

9. Organs of Generation, 290-294

I. Hermaphrodite Crustacea, 291

II. Female Crustacea, 292

III. Male Crustacea, 293

XIII. THE ARACHNOID AE.

Classification and Bibliography, 295

1. External Envelope, and Cutaneous Skeleton, 296-397

2. Muscular System, and Organs of Locomotion, 298-299

3. Nervous System 300-302

4. Organs of Sense, 303-305

6. Digestive Apparatus, 306-308

6. Circulatory System, 309-310

7. Respiratory System, 311-313

8. Organs of Secretion, 314—315

I. Urinary Organs, 314

II. Organs of Special Secretions, 315

9. Organs of Generation, 316-320

I. Hermaphrodite Arachnoidae, 317

II. Female Arachnoidae 318

III. Male Arachnoidae 319

XIV. THE INSECTA.

Classification and Bibliography, 321

1. External Envelope, and Cutaneous Skeleton, 322-323

2. Muscular System, and Locomotive and Soniferous Organs, 325-327

3. Nervous System, 328-331

4. Organs of Sense, 332-336

5. Digestive Apparatus, 337-339

6. Circulatory System, 340

7. Respiratory System, 341-344

8. Organs of Secretion, 345-347

I. Urinary Organs, 345-346

II. Organs of Special Secretions, 347

9. Organs of Generation, 348-355

I. Female Genital Organs 349-351

H. Male Genital Organs 352-854

Index,

CLASSIFICATION

OF THE

INVERTEBRATE ANIMALS.

§1.

The invertebrate animals are organized after various types, the limits
of which are not always clearly defined. There is, therefore, a greater
number of classes among them than among the vertebrates. But, as the
details of their organization are yet but imperfectly known, they have not
been satisfactorily classified in a natural manner.

There are among them many intermediate forms, which make it difficult
to decide upon the exact limits of various groups.

The following division, however, from the lowest to the highest forms of
organization, appears at present the best :

ANIMALIA EVERTEBRATA.

INVERTEBRATE ANIMALS.

Brain, spinal cord, and vertebral column, absent.

FIRST GROUP.

PROTOZOA.

Animals in which the different systems of organs are not distinctly sep-
arated, and whose irregular form and simple organization is reducible to
the type of a cell.

Class I. Infusoria.

Class II. Rhizopoda.

SECOND GROUP.

ZOOPHYTA.

Animals of regular form, and whose organs are arranged in a ray-likc
manner around a centre, or a longitudinal axis ; the central masses of the
nervous system forming a ring, which encircles the oesophagus.

Class III. Polypi.

Class IY. AcALEPiiiE.

Class V. Ecuinodermata.

16

CLASSIFICATION.

§2.

THIRD GROUP.

VERMES.

Animals with an elongated, symmetrical body, and whose organs are
arranged along a longitudinal axis; so that right and left, dorsal and
ventral aspects may be indicated.

The central nervous mass consists of a cervical ganglion, with or with-
out a chain of abdominal ganglia.

Class VI. Helminthes.

Class VII. Turbellarii.

Class VIII. Rotatorii.

Class IX. Annulati.

FOURTH GROUP.

MOLLUSCA.

Animals of a varied form, and whose bodies are surrounded by a fleshy
mantle. The central nervous masses consist of ganglia, some of which
surround the oesophagus, and others, connected by nervous filaments, are
scattered through the Jaody.

Class X. Acephala.

Class XI. Cephalophora.

Class XII. Cephalopoda.

FIFTH GROUP.

ARTHROPODA.

Animals having a perfectly symmetrical form, and articulated organs
of locomotion. The central masses of the nervous system consist of a
ring of ganglia surrounding the oesophagus, from which proceeds a chain of
abdominal ganglia.

Class XIII. Crustacea.

Class XIV. Aiiachnida.

Class XV. Insecta.

BIBLIOGRAPHY.

§2-

Besides the various ancient and modern works upon general comparative
anatomy, — such as those of Blumenbach,a> G. Cuvier,® F. Meckel, &) K.
Home ,1 2 3 (4) Bloinville ,<5) Belle Chiaje, (6) Carus, <7) Grant,® Rymer Jones, (S) Strauss

1 Handbucli der vergleichenden Anatomie. Got-
tingen, 1824.

2 Legons d’ Anatomie comparee. Paris, 1799-
1805. Translated into German and published with
notes and additions by Meckel and Froriep. 4 vols.
Leipzig, 1809-10. 2nd edit. Paris, 1835-45.

3 System der vergleichenden Anatomie. 6 vols.
Halle, 1821-33.

4 Lectures on Comparative Anatomy. 6 vols.

London. 1814-29.

•'» De l’Organisation des Animaux, ou Principea
d’Anatomie compare. Tom. I. Paris, 1832.

0 Istituzioni di Anotomiae Fisiologia Comparata.
Napoli, 1832.

7 Lehrbuch der vergleichenden Anatomie. 2nd
ed. Leipzig, 1834.

8 Outlines of Comparative Anatomy. London,
1841.

9 A General Outline of the Animal Kingdom, and
Manual of Comparative Anatomy London, 1841.

§2.

BIBLIOGRAPHY.

17

Burckkeim,a0) R. Wagner, m — there exist various contributions upon the
relations of these animals in the physiological works of Treviranus,{12) Ru-
dolphi,a3) Buges, (14) Burdachf5) J. Muller, m R. Wagner, a7) and in the
Medical Zoology of Brandt and Ratzeburg ,a8)

The iconographic illustrations by Cams and Otto,a9) and by R. Wag-
ner,(S0) contain many plates representing these animals; and in Guerin's
Iconographie ,<21) and Cuvier's (22> llegne Animal, edited by several French
naturalists, are many illustrations of their internal structure.

The following are some of the anatomical works which treat specially
upon these animals :

Schweigge'r. — Handbuch der Naturgeschichte der skelettlosen unge-
gliederten Thiere. Leipzig, 1820.

Belle Chiaje. — Memorie su la Storia e Notomia degli Animali senza
Vertebre del regno di Napoli. 4 vol. Napoli, 1823-20. 109 tavole.

A second and enlarged edition of this memoir has been published under
the following title : Descrizione e notomia degli animali invertebrati della
Sicilia citeriore. 1—5, vol. Napoli, 1841. Con tavol. I.-CLXXII.

Sars. — Beskrivelser og Jagttagelser over nogle moerkelige eller nye i
Havet ved den Bergenske Kyst levende Dyr af Polypernes, Acalephernes,
Badiaternes, Annelidernes og Molluskernes Olasser. Bergen, 1835.

Lamarck. — Ilistoire Naturelle des Animaux sans Vertebres. Deux,
edit., par Beshayes et Milne Edwards. 11 vols. Paris, 1835-45.

Milne Edwards. — Siemens de Zoologie, ou Le$ons sur l’Anatomie, la
Physiologie, la Classification, et les Moeurs des Animaux. Deux. edit.
Animaux sans Vertebres. Paris, 1843.

Richard Owen. — Lectures on the Comparative Anatomy and Physiology
of the Invertebrate Animals. London, 1843.

H. Frey and R. Leuclcart. — Beitrage zur Kenntniss wirbelloser Thiere
mit besonderer Beriicksichtigung der Fauna des norddeutschen Meeres.
Braunschweig, 1847.

. These same naturalists have prepared the second part of Wagner's
Lehrbuch der Zootomie, under the special title of: Lehrbuch der Anatomie
der wirbellosen Thiere. Leipzig, 1847.

Stef. Andr. Renter. — Osservazioni postume di Zoologia adviatica pub-
blicate per cura dell’ istituto veneto di scienze, lettere ed arti a studio del
Prof. G. Meneghini. Yenezia, 1847. Con tavol. I.— XVI.

10 Traits pratique et th^oretique d’Anatomie
compare. 2 vol. Paris, 1842.

11 Lehrbuch der Zootomie. 2nd edit,, entirely re-
vised 5 or “ Lehrbuch der vergleichenden Anato-
mic.” Leipzig, 1842.

12 Biologic. G vol. Gottingen, 1802-22. Also ;
Erscheinungen und Gcsetze des organischen Le-
bens. 2 vol. Bremen, 1831--33.

13 Grundriss der Physiologie. 2 vol. Berlin,
1821-28.

14 Traite de Physiologie compare de l’Hommeet
des Animaux. 3 vol. Montpellier, 1838-39.

3o Die Physiologie als Erfahmngswissenschaft,
erste Auflage, mit Beitragen von C. v. Baer,
Dic/Jenbach , J. Muller , R. Wagner. G vol.
Leipzig, 1826-40. 2 te Auflage, mit Beitraven von
E. Meyer , II. Rathkt , C. v. Siebolil und G. Val-
entin. 2 vol. Leipzig, 1835-37.

10 Handbuch der Physiologie des Menschen. 2
vol. 4th edit. Coblentz, 1844.

17 Lehrbuch der Physiologie. 2nd edit. Leipzig,
1843.

78 Medicinische Zoologie. 2 vol. Berlin, 1829-33.

Eriauterungstafeln zur vergleichenden Anato-
raie. 6 heft. Leipzig, 1826-43.

20 leones physiological. Eriauterungstafeln zur
Physiologie und Entwickelungsgeschichte. Leip-
zig, 1839. Also, leones Zootomies?. ITandatlas
zur vergleichenden Anatomie. Leipzig, 1841.

21 Iconographie du R£gne Animal de G. Cuvier,
ou Representation d’apres nature de l’une des
esp^ces les plus remarquables et sou vent non en-
core figurees de chaque genre d’Animaux ; pour
servir d’atlas & tous les Traites de Zoologie. 7 vol.
avec 450 planches. Paris, 1830-38.

22 llegne Animal de Cuvier , nouvelle Edition, ac-
compagn^e de planches gravies, &c. &c. Paris,
1836-47. Still unfinished.

2^

INTRODUCTORY NOTE TO THE INFUSORIA.

Constant labors in the whole department of microscopy, and that,
too, with greatly improved instruments, during the past few years, have
materially changed the face of the class Infusoria since the issue of this
work. There have been numerous and signal researches among all the
lower forms of animal life ; and the imperfect and undeveloped forms of
others, which are higher, have been wrought out with an accuracy and
detail before unknown.

These movements have all tended to diminish the numbers of the so-
called Infusoria, and it remains to be seen how large the proper class will
be when these researches shall have been further extended. By some even
it is believed that it will be entirely resolved into other classes ; this view,
however, would appear far from being warranted by our present knowl-
edge ; for, while, on the one hand, whole genera have been shown to be
only larval worms ( Bursaria , Paramcecium, &c., from Planaria ),* yet, on
the other, some forms have manifested phenomena and changes leading
us to place them almost unhesitatingly among individual animals. In
its best aspects, however, the subject has many perplexing points; and, in
its present unsettled state, it is almost hazardous for a scientific man to
entertain anything like positive views thereon.

I need scarcely allude to the vegetable, algous character which whole sec-
tions of the Polygastrica have recently assumed ; and the limits of this work
will not allow me to discuss in detail this and other interesting points. But
there are two or three topics of the highest physiological import, which
are prominently introduced by these studies. These are, What is a plant ?
What is an animal ? and, Are the animal and vegetable kingdoms on their
lowest confines separate and distinct from each other ?

As is well known, all the older criteria by which animals were separated
from plants have long since been regarded invalid; and some of those
which in late years have been regarded among the most constant, have,
quite recently, been declared as equally unsound. Cellulose has been
shown to be a component of animal as well as of vegetable structures, and
K'6lliker \ has insisted that some forms which have neither mouth nor stom-

*Agas$izy Ann. Nat. Hist. VI. 1850, p. j- Kclliker. Sicbold and Kolliker’s Zeitsch.
166. I. 1849, p. 198.

*

INTRODUCTORY NOTE TO THE INFUSORIA.

19

ach, but consist of a homogeneous 'mass, are true animals. If these
premises are correct, nothing will remain, as I conceive, for a distinctive
characteristic, but voluntary motion. This, when positive, is indubitable
evidence of anj given form being of an animal character ; and it must
remain for each individual observer to determine what is, and what is not,
voluntary action, in each particular case. Moreover, even should Killi-
ker's view of a stomachless animal prove correct, the inverse condition of
a true stomachal cavity being present, must, I think, be regarded as posi-
tive evidence of the animal nature of the form in question ; for this must
always be a distinctive characteristic of the two kingdoms, when present.

In regard to the other point, What constitutes an animal ? observers are
very far from being agreed. Siebold , K< lliker, and others, have taken
the ground that individual animal forms may be unicellular ; or, in other
words, that an animal may be composed of only a single cell.^ This view
is principally due to Kclliker' s observations and statements upon Gregari-
nae.t The facts are indeed striking, but the evidence does not appear to
me sufficient, as yet, to settle such a vexed and important question ; and
more especially so since Bruch X has raised the point of their belonging to
the Worms. But, aside from such grounds, I was led, some time since,
after considerable study of infusoria-forms, to venture an opinion quite at
variance with that just mentioned of Siebold and Kclliker. I then made
the following statement : In regard to the question, What characteristic in
organic animal matter shall constitute an individual ? I feel satisfied of
this much, — that cell processes, however closely interwoven they may be
witli the expressions of individual life, cannot be considered as constituting
the ground-work of its definition. ^ This statement was made more than two
years since ; and subsequent observations, some of them of a special char-
acter, have not led me to a change of opinion. True individual animal
life seems to involve a cycle of relations not implied in simple cells; in
other words, these last must always lose their character as such, in a definite
form which belongs to the individual.

On this account I regard the Infusoria proper, or those which have been
shown to be of an undoubted animal character, as in a completely transition
state; and, although it may be well to arrange these forms systematically,
for the sake of convenience, yet they cannot be considered as holding
fixed zoological positions. Further research in this direction, and upon
“ Alternation of Generation,” will, I think, widely clear up this obscure,
yet most interesting field of study. Editor.

* Siebold. Siebold and Kulliker's Zeitsch. I Bruch. Siebold and Kulliker’s Zeitsoh.
I. p. 270. > II. p. 110.

t Kclliker. Siebold and Kulliker's Zeitsch. § Burnett. Proceed. Boston Soe. Nat.
I. p. 1. Hist. V. p. 124.

BOOK FIRST.

INFUSOPyIA and ehizopoda.

CLASSIFICATION.

§3.

The Infusoria, using this word in a restricted sense, are far from being
the highly-organized animals Ehrenierg has supposed. In the first place,
on account of their more complicated structure, the Roti f era must be quite
separated from them, as lias already been done by Wiegmann, Burmeister ,
R. Wagner, Milne Edwards , Rymer Jones, and others. The same may
be said of the so-called Polygastrica. In fact, a great number of the
forms included under Closterina, Bacillaria, Volvocina, and others placed
by Ehrenierg among the anenteric Polygastrica, belong, properly, to the
vegetable kingdom. Indeed, this author has very arbitrarily taken for
digestive, sexual, and nervous organs, the rigid vesicles, and the colored
or colorless granular masses, which are met with in simple vegetable forms,
but which are always absent in those low organisms of undoubtedly an
animal nature. Cell-structure and free motion are the only two character-
istics in common of the lowest animal and vegetable forms; and since
Schwann ft) has shown the uniformity of development and structure of
animals and plants, it will not appear strange that the lowest conditions
of each should resemble each other in their simple-cell nature. As to
motion, the voluntary movements of Infusoria should be distinguished
from those which are involuntary, of simple vegetable forms ; a distinction
not insisted upon until lately. Thus, in watching carefully the motions of
Vorticellina, Trachelina, Kolpodea, Oxytrichina, &c., one quickly per-
ceives their voluntary character. The same is true of the power of . con-
tracting and expanding their bodies.

But in the motions of vegetable forms other conditions are perceived ;
and there is no appearance of volition in either change of place or form,
their locomotion being accomplished either by means of cilia, or other
physical causes not yet well understood. Cilia, therefore, belong to
vegetable as well as to animal forms, and in this connection it is not a little
remarkable that in animals they should be under the control of volition.
With vegetable forms these organs are met with either in the shape of
ciliated epithelium, as upon the spores of Vaucheria ,<2) or as long, waving
filaments, as upon che earlier forms of many confervae,® in which last can

1 Mikroskopische Untersuckungen, &c. Berlin, teurs des spores des Algues. Ann. des So. Nat.

1839 Botan. 1843, XIX. p. 266. PI. XI. fig. 29-30.

2 Tliuret. Recherches sur lea organes locomo- 1 2 The same. I’l. X.

§§ 4, 5.

INFUSORIA AND RIIIZOPODA.

21

often be seen the so-called organization of Ehrenberg's Monadina and
Volvocina. Until the fact that ciliated organs belong to both animals and
vegetables was decided, the real place of many low organisms had to
remain undetermined. <4) However, notwithstanding their free motion from
place to place by means of cilia, the vegetable nature of many organisms
seemed clearly indicated by the rigid, non-contractile character of their
forms. It is from a misapprehension of the true nature of these facts, that
some modern naturalists have denied the existence of limits between the
two kingdoms.®

With Bacillarese and Diatomaceae, this question has another aspect.
Many of these organisms have been taken for animals from their so-called
voluntary movements, which truly entirely want the character of volition.
In the movements of the rigid Diatomaceas, for instance, the whole plant has
oscillatory motions like a magnetic needle, at the same time slightly
changing its place forward and backward. When small floating particles
come in contact with such an organism, they immediately assume the
same motion. This may be well observed with the Oscillatoria. There
are here, undoubtedly, no ciliary organs ; in fact, they could not, if pres-
ent, produce this kind of motion. According to Ehrenberg,^ the iNaviculae
can protrude ciliary locomotive organs through openings of their carapace ;
but this has not been observed by other naturalists.

§4-

The Rhizopoda, whose internal structure is as yet imperfectly known,
are closely allied to the Infusoria. Like these last, their bodies are cellu-
lar, containing nuclear corpuscles, but no system of distinct organs. These
two classes of Protozoa differ, however, in their external form, and the
structure of their locomotive organs. The body of the Infusoria, notwith-
standing its contractility, has a definite form, and moves chiefly by means
of vibratile organs. That of the llhizopoda, on the other hand, although
equally contractile, has no definite form ; their movements also are not
due to ciliated organs, but to a change of the form of the body by various
prolongations and digitations.

§ 5.

Owing to the present incomplete details upon the organization of these
animals, little can here be said about them ; and therefore, instead of
devoting to them a separate chapter, it will be proper to treat of them
with the Infusoria in general.

As the division of the Polygastric Infusoria, by Ehrenberg , into two

4 As an example, may be mentioned the various
and dissimilar opinions of naturalists upon the
question of the animal or vegetable nature of the
“red snow j ” a question upon which FLntow ,
after the most careful studies, is still undecided.
See Flotow , “ Ueber Ilaematococcus pluvialis, ”
in Nov. Act. Acad. Leop. Carol, vol. XX. part ii.

p. 18.

6 See Unger , Die Pflanze im Momente der
Thierwerdung. Wien. 1843.

Also, Kiitzing , Ueber die Verwandlung der
Infusorien in niedere Algenformen. Nordhausen,
184-1.

In an academic paper (Dissertatio de finibus
inter regnum animate et vegetabile constiluendis,
Erlangae, 1844), I have attempted to show that this
confusion between the two kingdoms does not exist.

o Abhandlungen der Akademie der Wissen-
schaften zu Berlin, 1836, p. 134, Taf. I. tig. 19, and
1839, p. 102, Taf. IV. iig. 5.

INFUSORIA AND llHIZOPODA.

22

§5.

orders, Anentera and Enterodela, appears unfounded, the following class-
ification seems more natural :

PROTOZOA.

Class Infusoria.

Organs of locomotion chiefly vibratile.

ORDER I. ASTOMA.

Without an oral aperture.

Family : Astasiaea.

Genera : Amblyophis, Euglena, Cklorogonium.

Family : Peridinaea.

Genera : Peridinium, Glenodinium.

Family : Opalinaea.

Genus : Opalina.

ORDER II. S TO MATO DA.

With a distinct oral aperture and oesophagus.

Family: Vorticellina.

Genera: Stentor, Trichodina , Vorticella , Epistylis, Carchesium.

Family : Ophrydina.

Genera : Vaginicola, Cothurnia.

Family : Enciielia.

Genera : Actinophrys, Leucophrys, Prorodon.

Family : Trachelina.

Genera: Glaucoma, Spirostomum, Trackelius, Loxodes, Chilodon, Phialinu,
Bursaria , Nassula.

Family : Kolpodea.

Genera : Kolpoda, Paramcecium, Amphileptus.

Family : Oxytrichina.

Genera : Ozytricha, Stylonychia, Urostyla.

Family : Euplota.

Genera : Euplotes, Himantophorus, Chlamidodon.

§5.

INFUSORIA AND RHIZOPODA.

23

Class Rhizopoda. ■

Organs of locomotion consisting of completely retractile, ramifying
prolongations of the body.

ORDER I. MONO SOM AT IA.

Family : Amoebaea.

Genus : Amoeba.

Family : Arcellina.

Genera : Arcella, Diffiugia , Gromia, Miliola , Euglypka , Trinema.

ORDER II. POLYSOMATIA.

Genera : Vorticialis, Geoponus, NonioninaN

BIBLIOGRAPHY.

O. F. Midler. Animalcula Infusoria. Hafnize, 1786.

Ehrenberg. Die Infusionsthierchen als vollkommene Organismen.
Leipzig, 1838. Also his numerous and important memoirs upon the
Infusoria and Rhizopoda in the Memoirs of the Berlin Academy, and its
Monthly Bulletin.

Andrew Pritchard. A History of Infusoria, living and fossil, arranged
according to the “ Infusionsthierchen,” of Ehrenberg. Illustrated by
nearly 800 colored engravings of these curious creatures, highly magnified.
London, 1841.

Kutorga. Naturgeschichte der Infusionsthierchen, vorziiglich nach Eh-
renberg's Beobachtungen bearbeitet. Calsruhe, 1841.

Dujardin. Histoire Naturelle des Zoophytes. Infusoires, Paris, 1841.
This work treats also of the Rhizopoda.

ADDITIONAL BIBLIOGRAPHY.

Besides the various articles quoted in the additional notes I have made,
the following are among the more important recent writings on this subject :

Cohn. Bcitnige zur Entwickelungsgeschichte der Infusorien, in Sicbold
& Kolliker's Zeitsch. III. lift. 3, and IV. lift. 3.

Ecker. Zur Entwickelungsgeschichte der Infusorien, in Siebold & Kol-
liker's Zeitsch. III. lift. 4.

Stein. Neue Beitr. zur Kenntn. d. Entwickelungsg. u. d. feineren
Baues d. Infusionsthiere, in Siebold & Kolliker's Zeitsch. III. p. 475.

Pritchard. A History of Infusorial Animalcules, living and fossil, &c.,
with illustrations, new edition. London, 1852.

See also numerous notes in the Annales des Sciences Naturelles, since
1847. — Ed.

1 In this table are mentioned the families and genera of those only which have been the object#
of anatomical study.

24

INFUSORIA AND RHIZOPODA.

§§ 6, 7, 8.

CHAPTER I

EXTERNAL COVERING.

§6

The Protozoa are surrounded by a very delicate cutaneous envelope,
which is sometimes smooth,® and sometimes covered with thickly-set cilia.®
Generally these cilia are arranged, in longitudinal rows ; (3> but in Actino-
phrys they consist of long contractile filaments of a special nature.

With the Protozoa a distinct muscular tissue cannot be made out, but
the gelatinous substance of their body is throughout contractile.

It is only in the contractile peduncle of certain Vorticellina, that there
can be perceived a distinct longitudinal muscle, which, assuming a spiral
form, can contract suddenly like a spring.®

The Vibratile Organs on the surface of Infusoria serve as organs of
locomotion.

With many species they are found much developed at certain points,
and are arranged in a remarkable order and manner.

With Peridinium, a crown of them encircles the body; with Stylony-
chia, they are quite long, and surround the flattened body like a fringe ;
while the Vorticellina have the anterior portion of their body surrounded
by retractile cilia, arranged in a circular or spiral manner. In Trichodina
there is, upon the ventral surface, besides a crown of these cilia upon the
back, a very delicate ciliated membranous border, which is attached to a
ring which is dentated, and composed of a compact homogeneous tissue.
With Trichodina pediculus this border is whole and entire; but it is
broken or ragged with Trichodina mitra.a)

By means of this organ these animals swim with facility, or invade with
skill the arm-polyps and Planaria.® With many Infusoria, the vibratile
organs are situated at the anterior extremity of the body, as simple or
double non-retractile filaments, which move in a manner to produce a vor-

1 Euglena, Amoeba, (rc. 1 This Infusorium was discovered by me as a

2 Trachelius, Paramxcium, Nassula, (yc. parasite in many Planarieae.

3 Ampbileptus, Chilodon, Opalina, tyc. 1 2 3 F.hrenberg has entirely overlooked the ciliated

1 The peduncle is simple with Vorticella, but border oi Trichodina ptdtcu/us, and has regarded

ramified with Carchesium. With Epistylis it is the stiff serrations of the ring as movable hooks.

mns/>nl,r See “ Die Infusionsthiercben.” n. 206.

CHAPTER II

MUSCULAR SYSTEM AND LOCOMOTIVE ORGANS.

§§ 9, 10.

INFUSORIA AND RIIIZOPODA.

25

tical action of the water.® But with others the locomotive organ is a long
retractile proboscis.® With the Oxytrichina and Euplota, there are
fleshy movable points (uncini) upon the ventral surface, by which these
animals move about as upon feet. During these movements with the Oxy-
trichina, the posterior portion of the body is supported by many setose
and styloid processes, which point backward.

The singularly varied and branching locomotive organs of the Rhizo-
poda are short, and digitated with Amoeba , Difflugia and Arcella.'^ But in
the other genera they are elongated and filamentous.®

CHAPTERS III. AND IY.

NERVOUS SYSTEM AND ORGANS OP SENSE.

§9.

Although the Infusoria clearly evince in their actions the existence of
sensation and volition, and appear susceptible of sensitive impressions, yet
no nervous tissue whatever has as yet been found in them. If Ehren-
berg supposed the Polygastric Infusoria to possess a nervous system, he
did so because, having decided that the red pigment points of these ani-
mals were eyes, he inferred that they necessarily had a nervous ganglion
at their base.

§10.

With the naked Infusoria the sense of touch exists, undoubtedly, over
the whole body. But beside this, it appears specially developed, in many
species, in the long cilia forming vibratile circles, or in those movable
foot-like and snout-like prolongations of the body. In the same manner,
it is probable they have the sense of taste also ; for they seem to exercise
a choice in their food, although no gustatory organ has yet been found.

All species, whether they have red pigment points or not, seem affected by
light. Without doubt, therefore, their vision consists simply in discrimi-
nating light from darkness, which is accomplished by the general surface of
the body, and without the aid of a special optical organ.

The simple pigment point of many Infusoria,® and which Ehrenberg has
generally regarded as an eye,(2) has no cornea, and contains no body capa-
ble of refracting light ; there is, moreover, connected with it no nervous
substance.

Ehrenberg attaches here too great an importance to the red color of the

3 Amblyophis, Euglena and Peridinium , have
a simple fiagelliform cilium, but with Chlorogo-
nium it is double.

4 Trache/ius trichophorus feels about with a
long snout of this kind, without, however, produc-
ing a vortical action on the water.

5 See Ehrenberg , ‘‘Die Infusionsthierchen,”
Taf. VIII. and IX.

6 Gromia Jluviatilis , Miliola vulgaris , Vor-
ticialis strigilata , Euglypha tuberculosa , Tri-
nema acinus , according to Dujardin (Arm. des

Sc. Nat. Zool. IV. 1835, p. 343, pi. IX. ; also, V.
1836, p. 196, pi. IX. fig. A. See, also, his Histoire
des Infusoires, 1841, p. 249, pi. I. fig. 14-17 ; pi.
II. fig. 1, 2, 7 — 10 ; pi. IV. fig. 1); Geoponus Stel-
la borealis , Nonionina germanica , according to
Ehrenberg. Abhand. d. Berliner Akad. 1839,
p. 106, Taf. I. II.

1 Amblyophis , Euglena , Chloroc-onium , tyc.

2 Abhandl. d. Berliner Akad. 1831, p. 12 ; also,
“ Die Infusionsthierchen,” p. 491.

26

INFUSORIA AND RHIZOPODA.

11, 12.

pigment,® for the blue, violet and green pigments, seen in the eyes of in-
sects and Crustacea, show clearly that the red pigment is not essential to
the eye.*

CHAPTER V.

DIGESTIVE APPARATUS.

§11.

The Infusoria are nourished, either by taking solid food into the interior
of their body, or by absorbing by its entire surface nutritive fluids which
occur in the media in which they live.

This last mode is illustrated in the Astoma, which have no distinct oral
aperture or digestive apparatus. Ry the ingenious experiment first per-
formed by Gleichen ,(1) of feeding these animals with colored liquids, no trace
of these organs could be found.

Ehrenberg, who also had observed that they did not eat, regarded their
internal vesicles as stomachal organs, which were in connection with the
mouth by tubes. The correctness of this opinion, however, has not been
verified. Indeed, the genus Opalina <2) refutes it ; here the species are quite
large and visible to the naked eye, yet an oral aperture can be detected up-
on no part of their body, and never do they admit into its interior colored
particles. Solid substances found in them cannot be regarded as food.
That fluids are here introduced by surface-imbibition is shown by Opalma
ranarum ; this animal is found in bile in the rectum of frogs, and assumes
a green color. When Opalina requiring only a certain quantity of
liquid are placed in water, they quickly absorb it, become greatly swollen,
and shortly after die. In such cases, the absorbed liquid is seen as clear,
vesicular globules under the surface, and these globules have been taken by
Ehrenberg as stomachal vesicles (ventriculi), and by Dujardin as

VACUOLAE.

§12.

Those Infusoria which are nourished by solid food have a mouth at a cer-
tain place, and an oesophagus traversing the parenchyma of the body.
Through this last the food is received, and is finally dissolved in the semi-liquid
parenchyma of the body, without passing through stomachal or intestinal cav-
ities. In many cases there is at the end of the body opposite the mouth an
anus, through which the refuse material is expelled. But, when this is

3 “ Die Infusionsthierchen,” p. 492.

1 Auserlesene mikroskopische Entdeckungen,
1777, p. 51 *, also, Abhandlung tiber die Saaraen-
und Infusionsthierchen, 1778, p. 140.

* Some recent researches of Thuret (Ann. d. Sc.
Nat. 3rd ser. XIV. 1850) on the reproductive germs
of Algae prove that these bodies have red eye-
like specks, resembling those seen in the Polygas-
trica, but which disappear when the Zoospores at-
tach themselves and germination proceeds. The

2 The genus Opalina was first established by
Purkinje Valentin. Many species are found
in the rectum of frogs, and it is not rare to meet
with them in the alimentary canal of Planarieae.f

fact is a very interesting one in this connection. —
Ed.

f [§ 11, note 2.] According to Agassiz (Amer.
Jour. Sc. XIII. 1852, p. 425), Opalina is only a
larval form of Distoma. — Ed.

INFUSORIA AND RHIZOPODA.

27

$ 12.

wanting, its function is often performed by the mouth. According to
Ehrenberg , the Infusoria polygastrica, such as we have just been describ-
ing, differ from the Infusoria rotatoria, in having a great number of stom-
achs, which connect by hollow peduncles with the mouth in the division
Anentera, and with the intestine in that of Enterodela. This organiza-
tion, which, from its high authority, has generally been admitted by natu-
ralists, is not, however, met with in any infusorium. a)

The vesicular cavities in the bodies of these animals, and which have
been regarded by Ehrenberg as stomachal-pouches, never have a hollow
peduncle, either connecting with the mouth ( Anentera ) or with the intes-
tine ( Enterodela ). Indeed, it is doubtful if a digestive canal can be made
out in these Infusoria.

The vesicular, irregular contracting cavities of their body contain a
clear liquid, evidently the same as that in which they live, which, with the
Astoma, has been absorbed through the surface of the body. But, with
those having a mouth and oesophagus, it is received through them, and
taken up by the yielding parenchyma of the body.

If the methods of feeding of Gleichen and Ehrenberg are employed,
the colored particles are taken in by a vortical action of the water, caused
by the cilia surrounding the mouth. This water, with its molecules, accu-
mulates at the lower portion of the oesophagus, and so distends there the
parenchyma as to cause the appearance of a vesicle. Thus situated, the
whole has much the aspect of a pedunculated vesicle. But when, from
contractions of the oesophagus, this water escapes into the parenchyma,
it appears there as an unpedunculated globule, in which the colored
particles still float. When the 'Stomatoda are full-fed in this manner, there
appear many of these globules in various parts of the body; and thus sub-
stances previously ingested are taken up and disseminated throughout the
body.

If the globules thus containing solid particles are closely aggregated, it
sometimes happens that they fuse together ; a fact which proves that they
are not surrounded by a special membrane.

The solid particles of food of the Stomatoda, which are often the
lower Algae, such as the Diatomacese and Oscillatoria,and often other Infu-
soria, are sometimes deposited in the parenchyma without being surrounded
by a vesicular liquid.*

From observations made upon Amoeba, Arcella and Difflugia, it appears
that the Bhizopoda ingest their food like the Stomatode Infusoria.

1 Focke (Isis, 1836, p. 785) has already raised
doubts as to the existence in Infusoria of the
stomachs described by Ehrenberg. Ehrenberg
has also opponents in Dujardin (Ann. des Sc. Nat.
Zool. IV. 1835, p. 364 ; V. 1836, p. 193 •, X. 1838,
p. 230; also Ilist. Nat. des Infus. 1841, p. 57), in
Meyen {Muller's Arch. 1839, p. 74) and in Ry-
mer Jones (Ann. of Nat. Ilist. III. 1839, p. 105 ;
also, u A General Outline of the Animal Kingdom,”
1841, p. 56).

He has attempted to reply to the objections here
urged by very detailed illustrations of the organ-
ization of the Polygastrica, made by him and Wer-

neck. ( Muller's Arch. 1839, p. 80 ; also Monats-
bericht der Berliner Akad. 1841, p. 103.) But, de-
tailed as they may be (s ee Ehrenberg Abhandl. d.
Ber. Akad. 1830, Taf. III.; 1831, Taf. III.; also “Die
Infusionsthierclien,” Taf. XXXII. XXXVI. and
XXXIX.), they are not representations of nature.

The organ which in Trachelius ovum has been
taken by Ehrenberg (“Die Infusionsthierchen,”
p. 323, Taf. XXXIII. fig. xiii. 1) fora branching di-
gestive tube, has always appeared to me only as a
solid fibrous cord, traversing the soft parenchyma
of the body, and by its ramifications presenting a
coarse meshed aspect.

- * Bailey (Amer. Jour. Sc. May, 1853, p. 341)
has recently published ap account, accompanied
with numerous figures, of a new animalcule, which
is so remarkable in this connection that I give here
his description. He says : “ If the reader will

imagine a bag made of some soft extensible mate-
rial, so thin as to be transparent like glass, so soft
as to yield readily to extension when subjected to
internal pressure, and so small as to be microscop-
ic ; this bag, filled with particles of sand, shells of

28

INFUSORIA AND R1IIZ0P0DA.

§§ 13, 14.

§13.

If the vesicular cavities containing the liquid and colorless food of the
Stomatoda be examined under the microscope by a horizontal central inci-
sion, their contents appear colorless ; but by changing the focus, viewing
alternately the convex and concave surfaces of the vesicle, the points of
junction between the colorless globules and the parenchyma appear colored
pale-red. This appearance, due to an optical illusion, might easily deceive
one into the opinion that the vesicles which are really colorless are colored.

From this it is probable that Ehrenberg has described Bur Sana vernalis
and Trachelius meleagris as having a red gastric juice. (1)

The violet points which are found upon the back and neck of Nassula
elegans and Chilodon ornatus are only collections of pigment granules,
which, in the first case, are often absent, and in the second are often par-
tially dissolved.

This last violet liquid has been regarded by Ehre?iberg&) as a gastric
juice resembling bile.

§ 14.

The -solid particles of food, whether surrounded by the parenchyma or
enclosed in a liquid vesicle, are moved hither and thither in the gelatinous
tissue of the body, during the contracting and expanding movements of the
animal. In some, the parenchyma with itg contained food moves in a reg-
ularly circular manner, like the liquid contained in the articulated tubes of
Chara.(1) In Loxodes bursaria (2) this circulation is remarkable, and of much
physiological interest. Its cause is yet quite unknown, for in no case is it
due to cilia, and it may be observed in individuals entirely at rest. Ehren-
berg, (3> therefore, is incorrect in regarding it as due solely to a contratile
power of the parenchyma, displacing the molecules. Much less is his ex-
planation (4) satisfactory, since the digestive tube of an infusorium can be
exteuded at the expense of its stomachal pouches, so as to fill the whole
body, giving it the appearance of having a circulation of molecules through-
out its entire extent.

1 “ Die Infusionsthierchen,” pp. 321, 326, 329.
Ehrenberg has, moreover, in Trachelius melea-
gris, confounded the contractile cavities with those
non-contractile, and which receive the food.

2 Abhandl. d. Berliner Akad. 1833, p. 179 ; also
u Die Infusionsthierchen,” pp. 319, 338, 339.*

1 Vaginicola and Vorticella. See Focke , Isis,

Diatomacece, portions of Algae or Desmidieae, and
with fragments of variously colored cotton, woolen,
and linen fibres, will give a picture of the animal ;
to complete which, it is only necessary to add a
few loose strings to the bag to represent the varia-
ble radiant processes which it possesses around the
mouth.” This animal, which is often found with
bits of cotton protruding from its mouth, assumes
the most bizarre shapes. They appear to multi-
ply by fissuration and gemmation even when filled
with these heterogeneous particles, and, on the
whole, present characteristics as remarkable as

1836, p. 7S6 •, also Meyen , Muller's Arch. 1839,
p. 75.

2 Focke loc. cit.j also Erdl, Muller's Arch. 1841,
p. 278.

3 Loc. cit. p. 262.

4 Muller's Archiv. 1839, p. 81.

those of any animalcule with which we are ac
quainted. — Ed.

* [§ 13, note 2.] In this connection should be
noticed the experiments of Will ( Muller's Arch.
1848, p. 509). lie found evidences of a biliary ap-
paratus, with Vorticella , Epistylis , and Bursaria.
These evidences are based on chemical reaction,
and he describes no anatomical apparatus. I men-
tion this fact here, although Vor.ticella belongs
truly to the Bryozoa, and Bursaria to the Plana-
cia. — Ed.

§§ 15, 16.

INFUSORIA AND RIIIZOPODA.

29

§15.

The round or elongated oval mouth of Infusoria varies as to its posi-
tion. Sometimes it is in front, sometimes behind ; and in some cases, near
the middle third of the body. Rarely naked/11 its borders are generally
ciliated, (2) and often its circumference is provided with a very remarkable
ciliary apparatus. By the aid of this, these animals not only move about,
but when quiet produce vortical actions of the water, which are felt at
quite a distance; and all minute particles within its reach are quickly
drawn towards its mouth, and then swallowed or rejected according to the
option of the individual.®

It is rare that this oral aperture is provided with a dental apparatus. (4)
The oral cavity, generally infundibuliform, extends into a longer or
shorter, straight or curved oesophagus, which is lined throughout by a very
delicate ciliated epithelium.®

The anus, situated usually upon the dorsal surface of the posterior por-
tion of the body, is sometimes, though rarely, indicated by a slight exter-
nal projection.®

CHAPTERS VI. AN D VII.

CIRCULATORY AND RESPIRATORY SYSTEMS.

§ 16-

A vascular system entirely distinct by closed walls from the other
organs is not found in the Protozoa. But with very many (with all the
Stomatoda, without exception) there are contractile pulsatory cavities, the
form, number and arrangement of which is quite varied.

They are situated in the denser and outer layers of the parenchyma of
the body, and during the diastole they become swollen by a clear, trans-
parent, colorless liquid, which, during the systole, entirely disappears.

1 Actinopkrys. The mouth is naked also in the
genera DiJJlugia and Arcella of the Rhizopoda.*

2 Bursaria , Paramcccium , Urostyla and Sty-
lonychia. In Glaucoma scintillans 'the ciliated
crown of the mouth is replaced by a special semi-
lunar ciliated lobe.

3 In Stentor , Vurticella , Epistylis and Tricho-
dina , this apparatus is retractile, and produces in a
particular way the vortical actions. In Spirosto-
mum ambiguum , there is a long, narrow, ciliated
furrow, through which the food is conducted to the
mouth, situated at the posterior portion of the body.

4 Poqgodoii, Nassula , Chilodon and Chlamido-
don. ffere the hair-like teeth are arranged in a
cylinder so as to resemble a weir.

5 The cesophagus is short in Oxytricha , Sty-
lonychia , and Euplotes ; but is elongated or spi-
ral in Vorticella , Carchesium and Epistylis /

* T § 15, note 1.] KolliJcer ( Siebold and Kotti-
her's Zeitsch. 1. 1849, p. 198) has given a long and
detailed description of Actinophrys sol. Accord-
ing to him, it is without mouth or stomach proper,
and internally is composed of a homogeneous sub-
?># \

while it is long and arcuate in Bursaria trunca-
tella and cordiformis.

° The undigested matters accumulate about the
anus, and when this opens are expelled from the
parenchyma with a certain force. With Nassula
elegans , the greater or less portions of the Oscil-
latoria gracillima ( Kutzing ) upon which it
feeds, and which are of a blue-green color, dis-
solve into granules of this color. But these, dur-
ing the process of digestion, gradually assume a
brown color, and form irregular masses in the pos-
terior portion of the body, and are from time to
time expelled as brown fceces. These green gran-
ules are not therefore eggs, as Ehrenberg ( loc.
cit. p. 339) has supposed. This Nassula when
young is perfectly colorless, with the exception of
a beautiful blue spot.

stance. . Yet this remarkable animal lives on other
Infusoria, Algae, &c., and avails itself of them by
seizing and afterwards invaginating them in its pa-
renchyma, until they finally are included within its
interior. — Ed.

30

INFUSORIA AND RIIIZOPODA.

§ 17.

These movements succeed each other at more or less regular intervals.
When these cavities are numerous, a certain order in the succession and
alternation of their contractions cannot always be observed. It is very
probable that their liquid contained during the diastole is only the nutri-
tive fluid of the parenchyma, and to which it returns during the systole.
In this way it has a constant renewal, and all stagnation is prevented.
This arrangement constitutes the first appearance of a circulatory system,
and the first attempt at a circulation of nutritive fluids.

From an optical illusion similar to the one mentioned as belonging to
the vacuobe (§ 18) the liquid of these pulsating cavities has a reddish hue.(1)

§ 17-

A round, pulsating cavity is found in the genera Vorticella, Epistylis,
Loxodes , and in the following species : — Amoeba dijfiuens, Paramaecium
kolpoda, Stylonychia mytilus, Euplotes patella, SfC. With Actinophrys,
Bursaria, Trichodina, there are from one to two ; with Arcella vulgaris ,
three to four ; with Nassula elegans, there are four placed in a longitudinal
line on the dorsal surface. With Trachelius meleagris, there is a series
of eight to twelve upon the sides of the body, and with the various species
of Amphileptus there are fifteen to sixteen arranged more or less regularly.
With Stentor, there is a large cavity in the anterior portion of the body,
and many similar cavities appear upon the sides, united sometimes into
one long canal. A similar canal traverses the entire body of Spirostomum
ambiguum, and Opalina planariarum. With Paramaecium aurelia, the two
round cavities present a remarkable aspect, being surrounded by five or
seven others, small and pyriform, the top of which being directed outward,
the whole has a star-like appearance. (1) During the pulsation, often the
entire star disappears, sometimes only the two central cavities, and in some
cases the rays only.

These cavities, entirely disappearing in the systole, reappear in the dias-
tole, and usually in the same place and with the same form and number.
This would lead us to conclude that they are not simple excavations in
parenchyma, but real vesicles or vessels, the walls of which are so excess-
ively thin as to elude the highest microscopic power.

In some individuals, as, for instance, with Trachelius lamella, there
appear, during the diastole, two or three small vesicles at the extremity of
the body, which, after having increased in size, blend into one which is
very large. These are probably only globules of nutritive fluid, separated
from the parenchyma. Similar phenomena are observed in Phialina ver-
micular is and Bursaria cordiformis.

It sometimes happens with these animals that a forcible contraction of
the whole body divides an elongated cavity into two spherical portions, as

i Ehrenberg (loc. cit. p. 321, Taf. XXXIII. fig.
viii.), deceived by this illusion, has taken the eight
to twelve contractile cavities of Trachelius melea-
gris for stomachal cells, filled with red gastric juice,
lie has also regarded these cavities, when simple or
double, as seminal vesicles. (Abhandl. d. Berliner
Akad. 1833, p. 172, — 1835 p. 158.) In species
having but few, he has very arbitrarily decided that
some are seminal vesicles, others stomachal pouches,
as, for example, in Amphileptus (loc. cit. p. 355).
According to him, the seminal vesicles, upon con-
traction, pour the sperm upou the eggs contained

in the body. It really seems very strange that
these animals should practise uninterruptedly these
pollutions throughout their entire life. These ani-
mals have neither testicles nor ovaries, and the
function of these cavities is not, therefore, that
assigned to them by Ehrenberg, — but is, as I
think, with Wiegmann (Arch. f. Naturg. 1835, I.
p. 12), analogous to that of a heart.

1 Dujardin , Ann. d. Sc. Nat. Zool. tome X. PI.
XV. fig. 3 ; also, u Infusoires,” PI. VIII. fig. 6.
Ehrenberg'ls plates of these star-like vesicles are
incorrect.

$$ 18, 19.

INFUSORIA AND RHIZOPODA.

31

though it were a' drop of oil. The observation of these phenomena would
make it doubtful whether or not these cavities are true vesicles or vessels.

These cavities have been met with in only a few of the Astoma, and these
are, Cryptomoms wata <2) and Opalim planariarum.

§ 18.

The Infusoria appear to respire solely by the skin. In those species
whose bodies are covered with vibratile cilia this function is promoted by
the vortical action of the water caused by these organs. In others, the
contractile cavities just described are situated immediately under the skin,
and the opinion may be entertained that the water so communicates with
their liquid contents as to perform a respiratory function. In this re-
peat Actinophrys sol is quite remarkable, for its contractile cavities are
so superficial that when filled they raise the skin in the form of aqueous
vesicles, (1) which, however, are so elastic as entirely to disappear in the
parenchyma. Here it is plain that a mutual relation between the external
water and the contents of these cavities might easily take place.

CHAPTER VIII.

ORGANS OP SECRETION.

§ 19-

No special organ of secretion has been found in the Protozoa ; their
skin, however, has a power of secreting various materials, which in some
species harden and form a carapace, or a head of a particular shape ; while
in others it serves to glue together foreign particles, forming a case, in which
the animal retreats.

Among those having a carapace, may be mentioned Vagmicola, Cothur-
■nia, and Arcella. This more or less hard envelope does not resist fire,
and is probably of a corneous nature. In the Rhizopoda, however, it is
usually calcareous, like the shells of Mollusca, and is not affected by heat.
The Difflugiae carry about with them an envelope of this kind, composed
of grains of sand.

2 Ehrenberg , loc. cit. p. 41, Taf. II. fig. xvii.

1 Ehrenberg (Ibid. p. 303, Taf. XXXI. fig. vi. 1 ) appears to have taken the protrusion of these con-
tractile vesicles for that of a snout.

32

INFUSORIA AND RHIZOPODA.

§§ 20, 21, 22.

CHAPTER IX.

ORGANS OF REPRODUCTION.

§ 20.

The Infusoria propagate by fissuration and gemmation, and never by
eggs.™ They have therefore no proper sexual organs.

This fissuration occurs longitudinally with some,™ transversely with
others,® and in many of them by both at once.® Gemmation, on the
contrary, is very rare.®

§ 21.

Nearly all the Infusoria and Rhizopoda have in their interior a nicely-
defined body, a kind of a nucleus, which is quite different, in its compact
texture, from the parenchyma by which it is surrounded. This nucleus,
which, in different species, varies much in number and form, performs an
essential part in the fissuration. For, every time the individual divides
either longitudinally or transversely, this nucleus, which is usually situated
in the middle, divides also. So that, in the end, each of the two new individu-
als has a nucleus. When an animal is about to undergo fissuration, there is
generally first perceived a change in the nucleus. Thus, in Paramcecium,
Bursaria and Chilodon, the nucleus is sulcated longitudinally or trans-
versely, or even entirely divided,™ before the surface of the body pi'esents
any constriction.

This nucleus, which is of a finely granular aspect and dense structure, re-
tains perfectly its form when the animal is pressed between two plates of glass,
and the other parts are spread out in various ways. By direct light its color
appears pale yellow. It appears to lie very loosely in the parenchyma,
and sometimes individuals may be observed turning their bodies around it
as it rests motionless in the centre. From all this, it cannot be supposed
that this nucleus attaches itself to other parts of the animal, and especially
to the pulsatory cavities ( Vesiculce semvnales of Ehrenberg). &

§ 22.

A simple, round, or oval nucleus is found in Eugle?ia, Actinophrys,
Arcella, Amoeba, Bursaria, Paramoecium , Glaucoma, Nassula and Chilo-
don. But there are two which are round, and placed one after the other
in Amphileptus anser and fasciola, in Trachelius meleagris, and Oxytri-
cha pellionella. With Stylonychia mytilus, there are four.

1 That which Ehrenberg has arbitrarily taken
for eggs is sometimes granules of the parenchyma
or pigment corpuscles, sometimes bits of food. He
did not perceive that these bodies want all that which
is necessary to make up an egg, — such as chorion,
viteilus, and germinative vesicle and dot. It is on
this account that he declares that he never has
observed the hatching of young Infusoria. (Ab-
handl. d. Berliner Akad. 1835, p. 156.)

2 Vorticella , Carc/iesium.

3 This may be easily observed with Stentor,
Leucophrys , Loxodes , and Bursaria.

4 Bursaria , Opalina , Glaucoma , Chilodon , Pa-
ramoecium , Stylonychia and Euplotes.

i* Vorticella , Carchesium and Epistylis.

1 Ehrenberg , loc. cit. Taf. XXXVI. fig. vii. 13
to 19, Taf. XXXIX. fig. ix. 4, 5, 11-13.

2 Ehrenberg , from a strange fancy, has taken
this nucleus for a seminal gland. (Abhandl. d.
Berliner Akad. 1835, p. 163. Also, loc. cit.)

INFUSORIA AND RHIZOPODA.

$ 23.

It is not rare that a variable number of these round nuclei, arranged in
a row, traverse the body in a tortuous manner. This is so in Stentor
coeruleus and polymorphus, in S p i roslo rn urn am b igu urn , and in Trachelitis
moniliger. In many instances the nucleus has the form of an elongated
band, which is slightly curved in Vorticella convallaria, Epistylis leucna ,
Prorodon niveus and Bursaria truncatella. In Stentor Russelii , it is
spiral, and in Euplotes patella and Trichodina mitra , it is shaped like a
horse-shoe. In Loxodes bursaria , it is kidney-form, and encloses in one of
its extremities a small corpuscle (nucleolus).

The round nucleus of Euglena viridis has in its centre a transparent
dot. In Chilodon cucullulus, the nucleolus has a similar dot, and thus the
nucleus as a whole resembles a cell.

§ 23.

These nuclei, which make Infusoria resemble cells, deserve a special
attention, since they do not die with the animal. Thus the nucleus of
Euglena viridis , which, according to Ekrenberg,a) is globular when dying,
and surrounded by a kind of cyst, remains unchanged a long time, or even
increases in size, having no appearance of a dead body. It may be that
the life of this animal, under these circumstances, is not finished, but only
assumes another form.<2)

* Loc. cit. p. 110.

2 Perhaps this nucleus, of which the animal is
only a temporary envelope, is ultimately developed
into a particular animal. Indeed, perhaps this
species, as well as many others, are only the larval
states of other animals, whose metamorphoses are
yet unknown. It may properly be asked, if this
nucleus has not, relative to the body containing it,
the same signification as have the tubulous larvae
of Monostomum mutabile. (see below) to the em-
bryos they surround.

That the nucleus contained in Infusoria plays an
important part in the propagation of those animal-
cules, is supported also by a recent observation of
Focfce , who witnessed the development of several
young individuals in the nucleus of Loxodes bur-
saria. See Amtl. Bericht fiber die 22 tr. Versaaml.
deutsch. Naturforscher. in Bremen, Abth. ii. p.
110.

INTRODUCTORY NOTE TO THE ZOOPHYTA.

Within the past six or seven years the Zoophytes have received more
attention from naturalists than any other division of the animal kingdom.
The labors of many, if not most of 'our ablest naturalists, have been
directed towards an investigation of the humblest forms of animal life.
This fact, combined with the recent improved methods and means for
research, would alone be prophetic of the most signal advances in this
group ; indeed, our knowledge of all these forms has been so modified, as
well as increased, that previous writings need rather to be re-written than
revised. Dana, Agassiz, Milne Edwards, Forbes, Dalyell, Midler , Busch,
and others, not to mention the continued labors of older observers, have
effected these changes in this group.

The work of Dana is most excellent, and will remain a standard of au-
thority in this department for a long time to come. Aside from the many
details of structure, in it may be found the first and best philosophical
exposition of the relations of organic development with these lower plant-
like forms. Had this work been better known in Europe, there would have
been saved the constant repetition of the most grave errors. On the labors
of Agassiz no comment need be made; those who are in this department,
whether as minute Anatomists or philosophical Zoologists, will not fail to
understand and appreciate him. In the same field is Busch, who was
extended his brief though excellent labors over the three classes of this
whole group ; as for the remaining authors mentioned, excepting Muller,
their position in this department has long been established. Midler's
researches have been mostly on the Echinoderms, and the careful tracing
of the phases of their development and metamorphoses; but where so much
has been done, I fear the limits of this book will preclude full details with
this class.

This note would be unnecessary, were it not to show that I do not ignore
the changes and advance which have been made in this group within the
past few years ; and more especially so, as I have allowed, in this edition,
the classification to stand as in the original. Any great changes of this

INTRODUCTORY NOTE TO THE ZOOPHYTA.

35

kind I could not think of making without the consent of the authors, who,
although they would, undoubtedly fully, sanction them, are not sufficiently
accessible to me just now, as these pages are going to press. So, however
much the present classification may offend the eye of the Zoologist, yet the
Anatomist will find under each head the proper details. Thus, he will find
as full a description of the anatomical structures of the Bryozoa and
llydroid Polypi, as though they were referred to the Mollusea and Acal-
cphae, where truly they respectively belong. Editor.

BOOK SECOND.

POLYPI.

CLASSIFICATION.

§ 24.

Tiie Polypi are either immovably fixed, or seated on a locomotive
foot. Their soft body is in part enveloped by a solid support, the
polypary. This last is often, for the most part, horny or calcareous ; and
by it numbers of these animals are united into greater or less groups. The
central mouth is always surrounded by a coronet of contractile tentacles.
The digestive apparatus is organized after two different types, upon which
is based a division of these animals into two orders. The sexual appara-
tus is always without copulatory organs.

ORDER I. ANTHOZOA.

The digestive canal is without an anus, and opens into the general
cavity of the body.

Family : Madreporina.

Genera : Oculina, Millepora, Madrepora, Caryophyllia, Astraea, Desmo-
phyllum, Maeandrina , Monticularia , Agaricia, Favia.

Family : Gorgonina.

Genus : Gorgonia.

Family : Isidea.

Genera: Cor allium, Isis.

Family : Tobiporina.

Genus: Tulipora.

Family : Alcyonina.

Genera : Alcyonium, Lobularia, Alcyonidium.

Family : Pennatulina.

Genera : Veretillum, Pennatula, Virgularia.

$ 24.

THE POLYPI.

37

Family : Sertularina.

Genera : Sertularia, Campanularia.

Family : Zoanthina.

Genus: Zoanthus.

*

Family : Hydrin a.

Genera : Hydra , Eleutheria, Synhydra, Coryne, Syncoryne, Corymorpka.
Family : Actinina.

Genera : Actinia, Eumenides, Edwardsia.

ORDER II. BRYOZOA.

The digestive canal is closed from the general cavity of the body, and
opens behind through an anus.

Family: Reteporina.

Genera : Eschara, Cellepora, Flustra, Bicellaria, Retepora, Telegraphina,

Tendra.

Family: Alcyonellina.

Genera : Cristatella, Alcyonella, Bowerbanlcia, Vesicularia, Lagenella,
Plumatella, Lophopus.m

BIBLIOGRAPHY.

Ellis. Essai sur l’Histoire naturelle des Corallines et d’autres produc-
tions marines du rncme genre. La Haye, 1756.

Pallas. Elenchus zoophytorum. Hagae 1766.

Cavolini. Memorie per servire alia storia dei polipi marini. Napoli,
1785.

Rapp. Uebcr die Polypen im Allgcmeinen und die Aktinien insbeson-
dere. Weimar, 1829.

Ehrenberg. Die Corallenthiere des rothen Meeres, in the Abhandl. d.
Berliner Akad. 1832.

Johnston. A History of the British Zoophytes. Edinburgh, 1838.

Besides the important work of Dana, which will be often quoted in my
notes, the additions to the literature of the true polyps have been few since
the issue of this work, and have generally been published in the form of
articles in the various periodicals, to which reference will be made in my
notes. But the Bryozoa have been specially studied, and particularly in
the following papers :

l There are here enumerated only those families This remark applies equally to the following
whose organization has been specially studied, classes.

4

38

THE POLYPI.

§§ 25, 26.

Van Beneden. Recherches sur l’Anatomie, la Physiologie et le devel-
oppement des Bryozoaires. Mem. Acad. Brux. Tomes XYIII. XIX.
Recherches sur les Bryozoaires fluviatilesde Belgique. Ibid. Tom. XXI.
For further literature on the Bryozoa, see the writings quoted in my
notes, and especially those of Allman. Ed.

CHAPTER I.

CUTANEOUS ENVELOPE AND SKELETON.

§ 25.

The Polypi are composed of either entirely soft parts, 01 or have for their
support a solid frame, which may be calcareous, corneous, or coriaceous.
This frame is always the product of the general skin, and ought therefore
to be compared to a cutaneous skeleton.^ This skeleton, known by the
name of polypary , is formed partly internally, and partly externally, by
these animals. In the first case it is called an axial , and in the second a
tubular polypary.

The axial polypary consists, with some polyps,® of a dense substance,
apparently unorganized and composed of carbonate of lime ; with others,®
of a corneous substance, equally unorganized. When the polypary is
coriaceous, it is often covered by a variable number of calcareous, fusiform
corpuscles, usually bossed or dentated.<4) With some calcareous polyparies (5)
this is also true, and then the corpuscles are arranged in compact reticu-
lated masses. The tubular polyparies serve as a refuge for the animals
living in them, and in many cases, being common to many individuals,
these last are in direct relation to each other by the canals which traverse
the branching tubes. In the axial polyparies there are often cavities or
depressions of a variable size,® in which the animals can conceal them-
selves. When, however, these are wanting,® they retire, as is the case
with many soft polyps,® beneath their mantle. Sometimes,® these cavities
are closed by a movable operculum.

§ 26.

The skin of polyps is very transparent, and should be carefully dis-
tinguished from the parenchyma which it envelops. It is smooth, or it is
covered with ciliated epithelium. And, since it has been shown that many

p. 403, Taf. I.-III.) has described and figured these
spicula under the names of Spongolithis and
LithostyLidium.

5 The Madreporina.

6 Millepora , Madrepora , Oculina and Astraea.

7 Gorgonia, Isis and Corallium.

8 The Actiniae.

0 Eschara and Cellepora.

with Madrepora , Astraea , fyc. For the formation
of Coral, see Dana, loc. cit.; and for the relations of
the corallium carried out in detail, see Edwards and
Haime , Ann. d. Sc. Nat. 1849, ’50, ’51. — Ed.

1 The Actinina and Hydrina.

2 Corallium.

3 The Gorgonina.

4 These corpuscles are easily seen in Alcyonium
and Lobularia. ( Milne Edwards , Ann. d. Sc.
Nat,, Zool. IV. 1835, pi. XIII. fig. 9 ; FI. XV. fig.
10—11.) Spicula of this kind are found in the
interior of their tissues, as well as on the surface.
Ehrenberg (Abhand. d. Bed. Akad. 1811, Th. I.

* It should here be remarked that the old, and
as now regarded, mistaken view of the formation of
the frame of Polyps is here repeated; for the frame
Is generally an internal skeleton, as, for instance,

§$ 27, 28.

THE POLYPI.

39

Anthozoa have the skin, and especially the tentacles, covered with cilia of
this nature, (,) these last cannot be regarded as forming a differential charac-
teristic between them and the Bryozoa, as has been done by Ehrenberg .®

§ 27.

The skin of many polyps is quite remarkable in having nettling or
poisonous organs, to which it is only of late that the attention has been
directed. They consist of transparent vesicles, having a dense membrane,
of a round, oval, or cylindrical form, containing a clear liquid, and a very
delicate filament of variable length, which is usually spirally coiled. By
the least irritation of the skin, the filament is thrown out of the vesicle, of
which it appears to be only a prolongation. These filaments adhere to
objects coming in contact with the skin, and in this way the vesicles in
question are separated from it.(1) 2 These organs are probably the cause of
the nettling sensation felt when certain polyps are handled.

§ 28.

Still more interesting are organs analogous to those just mentioned, and
which belong to various species of Hydra. (l) They are found not only on
the arms, but also upon the skin of the body and foot. They consist of
oval vesicles, having a very long and delicate filament, which is slightly
swollen and viscous at its free extremity, while the opposite one is directly
continuous with the conical neck of the vesicle. The neck of each vesicle
is surrounded by three hooks curved backwards. These are always elevated
when the skin of the animal is irritated, and especially that of the arms
when they seize their prey. This last is then wound about by the free,
viscous end of the filament, and the attached vesicle being torn from the
body, the whole is often entangled in the arms of adjacent polyps. When
this occurs, the vesicles hang by their hooks to the arms of the polyps ; and
it is this that has given Ehrenberg the opinion that the vesicles are detached
by their round extremity, that these animals watch their prey with the
hooks erected, and that the vesicles and filaments can return into the inte-
rior of the arms.® But it is probable that they (the hooks) act more as
poisonous than as prehensile organs ; for if those from the arm of a Hydra
seize upon a Nats, a Daphnia, or a larva of Chironomus, these last quickly
die, even if they escape immediately after being taken.

1 Erdl has seen very distinct ciliated epithelium
in Actinia and Veretillum. (See Muller’s
Arch. 1841, p. 423.)

2 Abhandl. d. Berl. Akad. 1834, p. 255, 377.

1 These nettling organs, which are much more
common in the lower orders of the animal kingdom
than was at first supposed, are yet quite imper-
fectly known. Wagner first discovered them in
the Actinia , although he regarded them at first
as the spermatic particles of these animals. (Wies-
mann's Arch. 1835, II. p. 215, Taf III. fig. 7, also
1841, I. p. 41 •, leones Zuot. Tab. XXXIV. fig. 24.)
These researches have been extended by Erdl ,
who has shown that they also exist with Veretillum
and Alctjonium. (Muller's Arch. 1841, p. 423,
Taf. XV. fig. 3—6 and 8, 9.) In Alcyonium , Erdl
has observed the filament take, on its departure
from the vesicle, first a riband-like, and then a
spiral aspect. In Desmophyllum stellaria

(Ehrenberg), I have seen these cylindrical organs
having a long spiral filament. With Edwardsia ,
Quatrefages has found these organs upon the
whole surface of the body, as well as upon the
arms. (Ann. d. Sc. Nat., Zool. 1842, XVIII. p. 81,
PI. II. fig. 4-6.) For the nettling organs of the
Tubulariae and the Actiniae, see also Wagner in
Muller's Arch. 1847, p. 195, Taf. VIII.

1 These were first described by Ehrenberg.
(Mittheil. a. d. Verhandl. d. Gesellschaft naturf.
Freunde zu Berlin 2 tes. Quartal, 1886, p. 28 ; also,
Abhandl. d. Berl. Akad. 1835, p. 147 ; 1836, p.
133, Taf. II.) They have been carefully studied
by Erdl (Muller's Arch. 1841, p. 429. Taf. XV.
fig. 10-13).

2 Ehrenberg has figured, ideally (Abhandl d.
Berl. Akad. 1836, p. 133, Taf. 11. fig. 1) an Hydra
in the act of seizing its prey with extended hooks.
In reality this animal is never thus seen.

40

THE POLYPI.

$ 28.

These poisonous and prehensile organs are destroyed by use, which is
also true of the nettling organs. But this loss is probably repaired by their
speedy reproduction. This last circumstance may explain the various
descriptions given them by different authors, for, probably they have been
observed at dissimilar stages of development.,3)

3 Erdl , who has discovered a great number of
these nettling organs, saw, in some cases, the thread
directly continuous with the neck of the vesicle ; in
others, these necks appeared furnished with spines
directed backwards •, exactly as Wagner had
before described, and as Kolliker had often ob-

* [§ 28, note 3.] These nettling organs of the
Polypi have recently been very successfully studied
by A gassiz , who has enjoyed the most enviable
advantages with the Polypi and Acalephae of the
North American coast. He has changed the entire
aspect of the subject, besides almost exhausting it for
future research. His special studies were made on
the coral polyp of our southern coast, the Astrangia
Danae , Agass. The complexity of structure of
these lasso-cells , as he has very appropriately
termed them, is truly wonderful for such minute
forms. As I have also studied these forms, I will
use my own language, in the description of what
Prof. Agassiz has seen. There are several varieties
of these cells or capsules, depending upon the ar-
rangement and structure of the lasso ; sometimes
this last is a simple coil, sometimes it is coiled about
a staff which is erected from the base, but which is
also a part of the proje?tile apparatus. In the first
case, the lasso is much the longer and may be fifty
or seventy-five times the length of the vesicle; while,
in the second case, it rarely exceeds the length of
this last by more than sixteen or twenty times. In
all cases, the essential feature of these organs is the
lasso or internal coil, which is of a most curious
structure. In the first place, it is, in general terms,
only an inverted portion of the vesicle or cell itself,
an internal instead of an external cilium, coiled
up in a regular manner. When thrown out, there-
fore, it is wholly inverted, and its projection consists
of an instantaneous turning of the whole inside out.
But the lasso, delicate as it is, has still more delicate
structures on its surface. These consist of barbels
arranged in regular spiral rows, which extend
to the very extremity of the lasso. At this last

served (Beitrage z. Kenntniss d. Geschlechtsver-
haitnisse u. d. Samenfliissigkeit wirbelloser Thiere,
1841, p. 44, fig. 14). Erdl asks if these variations
of form are not coincident with an increasing or
decreasing activity of the sexual organs (see
Muller's Arch. 1842, p. 305). *

point, they almost elude the highest and best micro-
scopic powers. These barbels all point backwards
when the lasso is extended, and serve, no doubt, as
teeth, to prevent it from slipping on the objects over
which it is thrown. But these most delicate struc-
tures, which in beauty transcend that of all other
tissues, can be better appreciated by figures than
by the most minute description ; see Agassiz's
Memoir on Astrangia Danae (forthcoming in the
“Smithsonian Contributions to Knowledge”), PI.
VI. These observations, however, were made in
1848 ; see Proceed. Amer. Assoc. Advancem. Sc.
1848, p. 68.

From my own observations there would, indeed,
be nothing to add on the special points studied
by Agassiz ; but a remark or two may be made as
to the development of these forms.

The lasso-vesicle is, originally, only an epithelial
cell, of a spheroidal shape. It soon elongates, its
contents become cloudy, after which, the coil is
seen, very faintly marked, lying on the inner wall.
It would seem probable, therefore, that its forma-
tion was somewhat similar to that of the spiral
vessels in plants, although it is true that the lasso-
coils and these spiral vessels are analogous only in
form and position, and not in structure. The details
of the formation are unknown.

These lasso-cells are more widely distributed
among the Radiata than hitherto supposed. Agas-
siz (as he has informed me by letter) has observed
them on most of the Polypi and Acalephae, and even
with some of the Mollusca, and although their
general structure is the same, there are points of
difference of even a zoological value.

Editor.

§§ 29, 30.

THE POLYPI.

41

CHAPTER II.

MUSCULAR SYSTEM AND ORGANS OF LOCOMOTION.

§29.

The movements of Polyps are performed, partly by contractions of
the sides of their body, in which are found no muscular fibres, and partly
by a true muscular tissue. The fibres of this tissue have not regular trans-
verse striae, although during their contractions there are sometimes, though
rarely, seen irregular transverse bands. <n

§30.

In those Polyps having a true muscular system, this tissue is composed
of interlaced fibres, forming a layer beneath the skin. A coarse net-work
of this kind is seen in the arms of Hydra , although in the foot and rest of
the body there is scarce anything comparable to muscular fibres.11’ Under
the skin of Synhydra ^ and in the arms of Elcutheria&) this muscular system
is much more apparent. A similar layer, very distinct, is observed in Acti-
nia, which, in their mantle, is composed of both longitudinal and circular
fibres, the contraction of which draws the tentacles together, and this, com-
bined with that of the radiating fibres of the foot, gives rise to the various
forms of these animals.®

The Bryozoa have the muscular system more apparent ; in the cavity of
their body completely isolated fasciculi are seen, composed of parallel
fibres, serving especially for the withdrawal of these animals into their cells.
These fasciculi arise from the internal surface of the body, and are inserted
partly into the base of the tentacles, and partly into the neck and digest-
ive canal, — thus serving almost exclusively as retractors of these last.®

1 Milne Edwards , who declares he has seen
striated muscular fibres in Eschara (Ann. d. Sc.
Nat. VI. 1836, p. 3), must have been deceived. I
have been unable to perceive them in Eschara, Al-
cyonella, Cristatella, and other species. Nord-
mann also has not found them in Cellaria. (Ob-
serv. sur la Faune Pontique, 1840, p. 679 ; also
Miiller's Arch. 1842, p. ccviii.) The irregular bands
appearing during contraction, but afterwards disap-
pearing, have been observed by Quatre fanes with
Edwardsia (Ann. d. Sc. Nat. XVIII. 1842, p. 84,
pi. II. fig. 7, a-b).*

1 Corda, Nov. Act. Acad. C. L. C. Nat. Cur.
XVIII. 1839, p. 299. Also Ann. d. Sc. Nat. VIII.
1837, p. 363.

* [ § 29, note 1.] Busk has described and figured
the striated form of this tissue with Anguinaria
spatulata and Notamia bursaria. (Trans. Micro-
scop. Soc. of London, II.) I have been unable,
however, after considerable search upon many Bry-
ozoa, among which were several Alcyonella , to
detect any appearances of this kind ; and I would
venture a pretty confident opinion that in the spe-
4#

2 Quatrefages , Ann. d. Sc. Nat. XX. 1843, p.
238, pi. IX. fig. 3-5.

3 Quatrefages, Ibid. XVIII. 1842, p. 281, pi.
VIII. fig. 3.

4 Bertho/d, Beitr. zur Anat. u. Physiol. 1831, p.
16 ; also in the body of Edwardsia , Quatrefages
has found longitudinal and circular fibres (Ann. d.
Sc. Nat. XVIII. p. 84).

5 Similar muscles have been observed by Farre
(Phil. Trans. 1837, p. 387) in Bowerbankia , Vesi-
cularia, Lagenella and other Bryozoa. Milne
Edwards has seen them in Tubulipora and Es-
chara. (Ann. d. Sc. Nat. VIII. 1837, p. 324 ; VI.
1836, p. 23, pi. I. fig. 1, c, 1, d ; pi. II. fig. 1, a.)
Coste has given a very detailed description of the

cies examined no such form of muscle is present.
Quite lately, however, the subject has been care-
fully examined by Allman (Rep. Brit. Assoc. 1850,
p. 318), and his descriptions are such as to leave
no doubt upon the existence of the striated fibre
with the species he has examined, among which
are the Paludicellae. — Ed.

42

THE POLYPI.

31, 32.

With Eschara there are, moreover, two fasciculi in each cell, which move
its operculum, and thus close the entrance of this cavity.®

§31.

Locomotion is performed by the Polyps in various ways.

With the Hydrae, by their long-stretching arms; with Actiniae, by the
contractions of the disc of their foot ; ® while the Edwardsiae, having elon-
gated bodies which are not attached by a foot, progress by vermiform
movements.® With Cristatella mirabilis, the whole colony moves itself
along by the foot-like basis, like the Actiniae.^

Some Polyps, at a certain period of their development, move freely in
the water by discoid contractions of their body, like the pulmograde
Acalephae.®

§ 32.

A very remarkable peculiarity is the presence, in certain Bryozoa, of
organs shaped like a bird’s head, and which swing to and fro at the base
of their cells. In some species, these organs have the form of lobster’s
claws, being composed of both a fixed and a movable piece. This last is
corneous, and moved by a muscle which arises from a cavity in the first.
It is not yet known by what means either this beak is opened, or the
whole organ moves to and fro.®

Equally unknown is the function of these singular organs, the move-
ments of which persist after the death of the animal, and of which, there-
fore, they are independent.® They are perhaps organs of defence or pre-
hension, and analogous to the Pedicettarice of the Echinoderins.

muscles of Plumatella (Comp, renrl. XII. 1841, p.
724 5 Muller'’ s Arch. 1842, p. ccx).*

6 Milne Edwards , Ann. d. Sc. Nat. loc. cit. p.
24, pi. I. fig. 1, e.

1 Bert/iold , loc. cit. p. 14.

2 Quatrefages, Ann. d. Sc. Nat. XVIII. p. 74‘,
also Forbes , Ann. of Nat. Hist. VIII. 1842, p. 243.

3 I have been able to confirm the observation of
DalyeU ( Froriep's Notizen 1834, No. 920, p. 276)
upon this motion in Cristatella. Trembley , also,
has observed that the corallum of Plumatella
cristata moved half an inch in eight days (see
his M£moire pour servir a l’Hist. des Polypes d’eau
douce, 1775, p. 298).

4 See the observations of Steenstrup (Ueber d.
Generationswechsel, 1842, p. 20) upon Coryne fn-
ti/laria ; also those of Van Beneden (Mem. sur les
Campanulaires, 1843, p. 29, or Froriep's neue Noti-
zen, 1844, No. 663, p. 38) upon Campanu/aria ge-
latinosa.

* l § 30, note 5.] Allman (Report Rrit. Assoc.
1850, p. 314) has described a very complete mus-
cular system in the fresh-water Bryozoa. In the
species with bilateral lophophores, there are seven
distinct sets : 1. Retractor muscles of the polypide*,
2. The rotatory muscles of the crown ; 3. The
tentacular muscles ; 4. The elevator muscle of the
valve ; 5. Superior parieto-vaginal muscles ; 6.
Inferior parieto-vaginal muscles ; 7. Vaginal sphinc-
ter. The walls of the stomach also contain circular
muscular fibres.

1 These organs were first described by Ellis
(Essai sur l’Hist. Nat. des Corail. 1756, p. 51, pi.
XX. fig. A). Nordmann (Observ. sur la Faune
Pontique, 1840, p. 679, pi. III. fig. 4) has described
and figured them with much accuracy. In Cel-
laria avicularis , Bicellaria ciliata and Flustra
auicularis, they are formed like lobster’s claws.
In Retepora cellulosa they are pincer-like, and in
Telegraphina they are articulated stings. See
also Kro/in in Froriep's Notizen, 1844, No. 533,
p. 70.

For the organs having the form of a bird’s head
and a lash, and which are present in certain Bry-
ozoa, see also Van Beneden, Recherch. sur l’anat.
&c., des Bryozoaires, in the Nouv. M£m. de Brux-
elles, XVIII. 1845, p. 14, pi II. III., and Reid in
the Ann. of Nat. Hist. XVI. 1845, p. 385, pi. XII.

2 Darwin's Voyage of the Beagle, 1844, pt. I.
p. 252.1

With Paludicella, the muscular system is some-
what different ; there are here five sets, — the 1st.
5th, 6th, and 7th of the preceding, and the parie-
tal muscles. But with the 1st there is here only a
single instead of a double fasciculus. — Ed.

t [§ 32, note 2.] See Hincks (Ann. Nat. Hist.
VIII. 1851, p. 353), who regards these avicularia
as organs of defence, and has observed them seiz-
ing and retaining foreign bodies. — Ed.

33, 34.

THE POLYPI.

43

CHAPTERS III. AND IV.

NERVOUS SYSTEM AND ORGANS OF SENSE.

§33.

As yet only a very rudimentary and imperfectly distinguished nervous
system has been made out in the Polyps ; this consists of round masses,
which are regarded as composed of nervous matter (ganglia), situated in
the parenchyma. A ganglion of this kind has been supposed to have been
observed about the mouth.™

§34.

Investigations upon their organs of sense have rrot been more suc-
cessful. However, the sense of touch appears developed over the whole
surface of the body, but specially so in the extremely irritable arms and
tentacles. But, as yet, no tactile nerves have been found in these parts.
In the same manner, light, to which these animals show a greater or less
sensibility, is perceived rather by the general surface of the body than by
special organs.

There are, however, in some species, at particular stages of development,
during which they swim freely about, certain nicely-defined bodies situated
upon the sides of the body, and which may be regarded as special organs
of light and sound. This is the case with Syncory^e ;(I) and Coryne (2) has in
their place four red organs which correspond exactly to those found on the
border of the disc of the pulmograde Acalephre, and which have been re-
garded as organs of sense.

The organ seen at the base of the six arms of Eleutheria dlchotorna
has quite the appearance of an eye ; that is, there can be distinguished in

1 A double oesophageal ganglion has been ob-
served by Dumortier (Mem. sur V Anat. et la
Physiol, d. Polypiers composes d’eau douce 1836,
p. 41, pi. II. fig. 2) in Lophopus cristallinus ( Pin -
mateila cristata of Lamarck) ; and by Coste
(Comp. rend. XII. 1841, p. 724)in the Plumatel/ae
in general. N ordmann also has seen a similar
ganglion under the mouth of P Inmate lla campa-
nulata (Lamarck) (loc cit. p. 709), and of Teadra
zostericola (Ann. d. Sc. Nat. XI. 1838, p. 190).
According to Kan Beneden, a nervous ring sur-
rounds the oesophagus of ALcyonella (Ann. d. Sc.

* [§ 33, note 1.] Allman has observed with
Cristatella mucedo a small roundish body situated
at the upper end of the pharynx, and which he re-
gards as a nervous ganglion (Rep. Brit. Assoc. Ad-
vancem. of Sc. 1846, p. 88). This observation he
subsequently confirmed, and has observed with
Plamaltlla repens this ganglion ( which he terms
the great oesophageal ganglion) send off a large
filament to each of the tentaculiferous lobes ; also
a smaller one passing off at each side to embrace
the oesophagus, while a very short one was distrib-

Nat. XIV. 1840, p. 222). Coste asserts the presence
of a nervous system in Pennatula ( Proriep's neue
Notizen, 1842, No. 450, p. 154). That which Spix
pretended to have discovered in the foot of Acti-
nia (Ann. d. Mus. d’llist. Nat. 1809, p. 443, pi.
XXXIII. fig. 4) has been properly rejected by
most modern zootomists, as au illusion. See Ber-
thold , loc. cit. p. 6.*

1 Lov^n, fViegmann's Arch. 1837, I. p. 323.

2 Steenstrup , Ueber den Generations wechsel, p.
23.

uted in the substance of this last organ. And,
finally, another set of filaments were distributed to
the organs about the mouth. See Report of the
same, for 1849, p. 72. According to a late Report,
this observer appears to have been able to make
out a distinct nervous system in all the fresh-wa-
ter Bryozoa, except Paludicella. He has, how-
ever, been able to detect no certain organ of spe-
cial sense. See report of the same for 1850, p.
319. — Ed.

44 THE POLYPI. §§ 35, 36.

it a cornea, a crystalline lens and a red pigment layer surrounding the
whole.®

Furthermore, there are upon the border of the disc of the campanulate
Campanularia, colorless corpuscles, containing a calcareous nucleus, which
is transparent as a crystal and soluble in acid.

These organs should probably be regarded as the most simple form of
the auditory organs, for they have only a simple vestibule with its single
otolite.w

CHAPTER V.

DIGESTIVE APPARATUS.

§35.

The digestive apparatus of Polyps is formed after two different types.
With the Anthozoa it consists of a mouth and a simple stomachal sac with-
out an anus. But with the Bryozoa, there is a mouth and anus, and a
digestive canal which may be divided into the sections of oesophagus,
stomach, small intestine and rectum.

§36.

The mouth of Polyps is usually surrounded by a circle of long, very
contractile tentacles or arms. These tentacles are tubular, and connect with
the cavity of the body.(1> They are simple, (2) or pennate,® and may be dis-
posed around the mouth in a single® or a multiple® circle ; they are also
frequently covered with cilia.®

Thus, the cylindrical tentacles of Actinia are entirely covered by ciliated
epithelium. With the Bryozoa, on the contrary, the slightly-flattened ten-

3 Quatre.fages, Ann. d. Sc. Nat. XVIII. 1842,
p. 280, pi. VIII. fig. 1, d, d, and fig. 6.

4 See Krohn ( Muller's Arch. 1843, p. 176) and
Kolliker ( Froriep's neue Notizen,1843, No. 534, p.
81). Van Beneden has perceived in the campa-
nulate and free individuals of Campanularia ge-
latinosa and geniculata , not only eight marginal
bodies, each containing a calcareous nucleus, but
also four nervous ganglia about the base of the
stomach (Mlm. sur les Campanulaires de la cdte
d’Ostende, 1843, p. 24-27, pi. II. III.). I am yet
undetermined upon the question whether, as Van
Beneden thinks, these bodies have sometimes the
function of organs of vision, and sometimes that
of organs of hearing. I am also in doubt as to the
opinion of Huschke (Lehre von den Eingeweiden
und Sinnesorganen, 1844, p. 880), who regards as
otolites the calcareous bodies which have been ob-
served in the peduncle of Veretillum cynomo-
rium. Nordmann (Versuch. einer Monogr. des
Tergipes, p. 88) has described as auditory organs
the marginal bodies of the free-swimming Campa-
nulariae.

1 This cavity which is in the arms of most Polyps

*l§36, note 1.] Subsequent researches have
shown that the cavity of the tentacles does open
externally through a small papilla. See Dana,

does not open outwards at the extremity of these
organs. I doubt, in fact, if the Actinina are an ex-
ception to this. It therefore appears singular that
Rymer Jones (A General Outline of the Animal
King. p. 41, fig. 13), and Lesson (. Duperrey , Voy-
age autour du Monde. Zoophytes, p. 82, No. 1, fig.
1), expressly mention and distinctly figure these
openings •, the first with an Actinia , the second
with an Eumenides. According to Van Beneden
(loc. cit. p. 15) the tentacles of Campanularia
are without these cavities. But this is contradict-
ed by Lovdn ( Wiegmann's Arch. 1837, Bd. 1, p.
252). In Hydra the cavities open distinctly into
the stomach, as is probably the case with many other
Hydrina. Frey and Leuckart likewise doubt the
constant presence of an orifice at the apex of the
tentacles of the Actiniae .*

2 Actinia , Hydra , F lustra and Campanularia.

3 Veretillum , Lobular ia, Isis, Gorgonia , and
Zoanthus.

4 Hydra , F lustra, Zoanthus and Veretillum.

5 Actinia and Cary ophy Ilia i

6 Veretillum , Flustra , Eschara , Cristatello
and Tubulipora.

Structure and Classification of Zoophytes. Phil.
1846, p. 32. — Ed.

§ 37.

THE POLYPI.

45

tacles have only a single row of cilia, which move regularly and volunta-
rily, like the rotatory organs of the Rotatoria.

By means of the currents produced by the cilia of their tentacles, many
Polyps draw towards their mouth light particles of food ; (7' others make
use of their ciliated arms to seize larger portions.® This act is aided by
the nettling and various prehensile organs, which are more usflally^ found
upon those Polyp-arms having no cilia.® These organs are found up&n the
tentacles of Actinia, Edwardsia, Veretillum and Alcyonium, and without
doubt serve for the seizing of the prey as well as its retention until death.

But these should not be confounded with special prehensile organs found
on the tentacles of certain species. These consist of a small coriaceous
capsule, from which the animal can project a kind of sting. <10) By means of
these organs, the animal can attach itself like a bur to external objects,
and not by suction, as is generally supposed.

The circular or oval mouth is always situated in the centre of the an-
terior extremity of the body ; it is often surrounded by a lip formed of
circular fibres. (U) In a few species, the mouth projects like a cone at the
base of the tentacles. a2) With the Plumatdlaea?j) the mouth is topped by a
tonguelet covered with rapidly moving cilia. Some of the Anthozoa,
which capture animals of considerable size, can, in swallowing them, dilate
their mouth to an astonishing width. (I4)

DIGESTIVE CAVITY OF ANTHOZOA.

1 §37.

The simple stomach of Anthozoa, which is of a variable length, opens
in general directly external by means of the mouth, (1) and with a few
species, only, is there a muscular oesophagus.®

With some, the stomach blends with the walls of the body,® but usually
it is more or less isolated. There remains, therefore, a cavity of the body
of variable size, and which is directly continuous with the cavities of the
arms. In those Polyps living in colonies, it is prolonged into canals trav-
ersing the corallum, and in this way the cavities of the bodies of all the

7 Flustra , Eschar a , Tubulipora and Crista-
tella.

8 Actinina.

9 Hydra , Coryne , Eleutheria , Sertularia , Cam -
panularia and Alcyonium.

10 Such prehensile organs have been observed by
Quatre/’ages upon the clavate tentacles of Eleu-
theria. He thinks also he has observed two mus-
cles in their capsules, by which the retractile sting
is projected (Ann. d. Sc. Nat. XVIII. 1842, p. 276
and 233, pi. VIII. ; or Froriep's neue Notizen,
1843, No. 543, p. 230). The oval Vesicles which
roughen the tentacles of Campanularia , and which
Lovdn (IFiegmann's Arch. 1837, 1. p. 252) has de-
scribed as small spinous warts, are probably of the
same nature. In Hydra each hook-organ upon the
arm is surrounded by a group of similar vesicles, in
the interior of which is a rigid bristle. These or-
gans are here found only upon the arms. They
are distinguished from the organs having hooks by
their less size, and from their having no project-
ing filament. Corda has not properly distin-
guished them from the hook-organs, whose fila-

ment is still unprojected (see his Memoir in the
Nov. Act. physico-medica. XVIII. p. 300, Tab. XV.
fig. 5, 9, 10). Perhaps the organs which Erdl
( Muller's Arch. 1841, p. 424, Taf. XV. fig. 3) has
seen upon the tactile lobules of Veretillum cyno-
morium are of this kind.

11 Actinia and Edwardsia.

1‘- Hydra , Coryne and Campanularia.

13 Alcyonella and Cristatella.

14 Actinia and Hydra.

1 Veretillum , Alcyonium , Actinia and Hydra.

2 Edwardsia. See Quatrefages (Ann. d. Sc. Nat.
XVIII. pi. I. fig. 2 ; pi. II. fig. 1, 2).

3 Hydra. The stomach of the arm-polyps is not,
as has been formerly supposed, a simple excavation
in the body. It has proper walls distinct from
those of the body, by which, however, they are
closely embraced. There is, therefore, in Hydra
no cavity of the body, and the cavities of the ten-
tacles open directly into the stomach. This is also
true of Eleutheria (Quat ref ages. Ann. d. Sc. Nat.
XVIII. p. 283).

46

TIIE POLYPI.

§37

Polyps are placed in direct intercommunication. It is not rare to find
this general cavity divided into chambers by mesenteric membranes stretch-
ing longitudinally from it to the external surface of the stomach.®

The base of the stomach of many, and perhaps all of the Anthozoa, is
pierced by one or more valvular openings, which communicate with the
cavity of the body.® These animals, by controlling at will these orifices,
can alffew to pass into the cavity of the body the proper materials, which
are probably water and liquid chyle.® This digestive apparatus thus com-
municating with the cavity of the body, reminds one of the organization
of the Infusoria.®

The cavity of the stomach is lined by very delicate ciliated epithelium,
which is continuous through the orifices upon every surface of the cavity
of the body and arms, and even into the intercommunicating canals of the
corallum.

The color of the walls of the stomach is quite varied, and is due to cer-
tain pigment cells which very probably perform the function of a liver ;
for these animals arc entirely wanting in any other glandular appendix of
the alimentary canal, analogous to a liver.®

4 There are often eight of these longitudinal
chambers, as in Veretillum, Alcyonium and Al-
cyonidium (see leones zoot. Tab. XXXIV. fig. 2 ;
also Ann. d. Sc. Nat. IV. 1835, pi. XVI. fig. 3, and
pi. XII. fig. 3, 4). In Actinia there are seven
more. With Edwardsia the eighth mesenteric di-
visions do not reach the sides of the body ( Qua -
trefages loc. cit. pi. I. fig. 2).*

o These orifices were long ago observed by the
elder anatomists upon various Polyps. After-
wards their existence was incorrectly doubted by
other naturalists 5 for lately they have been dis-
tinctly made out. Thus, in Veretillum cynomo -
rium (Rapp, Nov. Act. physico-medica XIV. 1829,
p. 650), in Atcyonidium and Alcyonium ( Milne
Edwards , Ann. d. Sc. Nat. IV. p. 325, pi. XV. fig.
6), and in Edwardsia ( Quatrefages Ann. d. Sc.
Nat. XVIII. p. 91).

In Sertularia and Campanularia there are
openings between the stomach and the tubulous
cavities of the corallum ( Lister , Phil. Trans. 1834,
p. 371, and Van Beneden, Mem. sur les Campanu-
iaires, loc. cit. p. 17). There must be direct com-
munication of this kind with the Actiniae , since
they regularly reject by their mouth nettling fila-
ments, from the chambers of their body. With
Hydra , the stomach communicates, by an orifice
situated at its base, with the narrow tubulous cavity
of its cylindrical foot. But at the extremity of this
tube there is no oval opening, and the tube itself can-
not be regarded as a rectum, for it receives neither
faeces, nor fragments of food, and is not affected by
the frequent enormous dilatations of these animals
from surfeit. Cor da therefore is incorrect in as-
signingan anus to these animals. (Nov. Act. phys-
ico-medica XVIII. p. 302, Tab. XIV. fig. 2, E.) lie
appears to have entirely neglected the foot of this
animal, which, however, has been well figured by
E/irenberg (Abhandl. d. Berl. Akad. 1836, p. 134,
Taf. II fig 1); and since Roesel (Insektenbel III
Taf. LXXVIII. and LXXIX. fig. 2, and LXXXVI.
LXXXVIII. fig. 6) has perceived it in all unmuti-
lated arm-polyps. Sars (Faun, littoral. Norveg, p.

* [§ 37, note 4.] With all the Actinaria the 1am-
ellze of the visceral cavity are the multiples of
six ; all the Alcyonaria have eight of these lamellae.
See Dana loc. cit. p. 49. — Ed.

t l $ 37, note 5.] With the Actinoidea, recent
researches have shown that the stomach communi-

21) has found with a Lucernaria a stomach opening
interiorly, and communicating directly with the
cavity of the body. This communication has been
observed also by Frey and Leuckart (Beitr. p.
3) with the Actiniae and several other Anthozoa. t

6 Quatrefages (Ann. d. Sc. Nat. XVIII. p. 87,
91) has seen the stomach of Edwardsia entirely
filled with Spirorbis , and other solid food, without
any of it passing into the cavity of the body.

7 With Infusoria, the lower end of the oesophagus
is free, so that the food passes directly from it into
the parenchyma of the body, where it forms a cav-
ity ; but with the Anthozoa, there is a stomach,
from which chyle alone can pass into the cavity of
the body.

# These cells are white in Edwardsia , yellow in
Atcyonidium and Alcyonium , and brown in Vere-
tillum and Hydra. In the last, the brown is dis-
tinctly due to irregular pigment granules of that
color, floating in the clear liquid of the cell. Prob-
ably these cells, by bursting, empty their contents
into the stomach ; at least, I have been able to find
no excretory duct, such as Corda has figured with
the Hydra fusca (Nov. Act. Acad, physico-medica
XVIII. p. 302, Tab. XV. fig. 15 — 17 •, or Ann. d.
Sc. Nat. VIII. p. 366, pi. XIX. fig. 15—17).

In Hydra viridis , these brown cells of the stom-
ach can easily be distinguished from the layer of
green pigment belonging to the parenchyma of the
body. Moreover, if a transverse section of this
animal is made, there appears a wide difference of
organization between the internal and external sur-
face of the stomach; the first lias ciliated epithe-
lium and hepatic cells, the second a bare skin with
prehensile organs. This being so, how can these
animals be everted like the finger of a glove, as some
naturalists have affirmed, and yet live ? for the two
surfaces of the stomach, so different, could not re-
place each other, and then again the cavities of the
arms would open directly outward. Indeed, it is
not possible to return unmutilated an everted
Polyp, since the inextensible cavity of its foot can-
not leave the body with impunity. The gastric

cates with the cavity of the body by a single ori-
fice only, which may be closed by muscles. See
Dana , loc. cit. p. 40, 44, pi. XXX. fig. 3, a, b, c, d.
It has been since verified by Cobbold , Ann. Nat.
Hist. XI. 1853, p. 121, with figures. — Ed.

$$ 38, 39.

THE POLYPI.

47

DIGESTIVE CAVITY OF BRYOZOA.

§ 38.

The very complicated digestive canal of the Bryozoa floats freely in the,
spacious cavity of their body. It is composed of an oesophagus which, at
its lower extremity, dilates into around or oval muscular crop ;d) upon this
immediately succeeds a coecal stomach, from the upper portion of which a
small intestine arises and passes upwards in front. This, after a course of
variable length, ends by a constriction in a short but large rectum, which
opens in the vicinity of the mouth, at the external side of the base of the
tentacles.® The digestive canal here, therefore, is not in communication
with the cavity of the body. Its whole inner surface is lined with very
active, ciliated epithelium, which keeps its contents in motion, and especially
the fasces of the rectum. The sides of the stomach are often colored brown,
yellow or green, from the presence of hepatic cells.!

CHAPTERS VI. AND VII.

CIRCULATORY AND RESPIRATORY SYSTEMS.

§ 39.

A vascular system has yet been found only with a few Polyps ; but there
it is so apparent that its presence in others may be inferred. The blood-
vessels exist upon both the sides of the body and of the stomach, and are
in part longitudinal, in part circular, ending in a capillary net-work. They
are not simple canals excavated in the parenchyma, but have proper walls,
and circulate a liquid containing a great number of white (blood) globules. (1)

juice of the Anthozoa must have a very great
digestive power, since the Actinia eat hard-shelled
Crustacea, and even the soft Hydrae quickly dis-
solve the larvae of Nais and Chironomus. But
the indigestible parts ot these animals, such as epi-
dermis, bristles, hooks and jaws, are afterwards
ejected by the mouth.

1 In Bowerbankia ( Farre , Phil. Trans. 1837,
p. 392, PI. XX. fi". 5 ; PI. XXI. fig. 7) this crop
is oomposed of pyramidal corpuscles, with the
apices pointing inward, so as to act like teeth. I
have observed a very similar structure in Alcyo-
nella sta^norum.

2 In Bowerbankia and Vesicujaria the small
intestine is very long {Farre. loc. cit. PI. XX. and
XXII). I have observed it very short with Cris-
tatella mirabilis.*

k [§ 38, note 2.] According to Allman (Report
Brit. Assoc. 1850, p. 310), the oesophagus succeeds
the stomach without the intervention of any dis-
tinct crop with all the fresh-water Bryozoa. The
stomach is large and thick-walled, and may be
divided into a cardiac and a pyloric portion. The
pylorus is distinctly valvular, and the intestine,

1 Milne Edwards has perceived a vascular net-
work of this kind in the sides of the body, with
Alcyonidium elegans , and Alcyonium palma-
turn and stellatum (Ann. d. Sc. Nat. IV. p.
338). Quite recently, Will has described the vas-
cular system of Alcyonium pa/matum {Froriep's
neue Notizen, 1843, No. 599, p. 68). According to
him, white vessels may be perceived, even with the
naked eye, upon the longitudinal furrows of this
animal. These enter the lobules on the border of
the body, and there form a dense net- work, from
which a branch is sent to each arm, and this last
gives off laterally a twig to each tactile lobule. The
principal trunk of the longitudinal vessels con-
tinues upon the sides of the stomach to the base of
the tentacles. At the point where the bodies of
the Polyps continue with the corallum, there are

wide at first, passes along the side of the cardiac
cavity and oesophagus, and rapidly decreases in
diameter, until it terminates in a distinct anus just
below the mouth. — Ed.

t [ Note at end of § 38.] See in this connection
my note under § 13, note 2. — Ed.

48

TIIE POLYPI.

§§ 40, 41.

§ 40.

All Anthozoa and Bryozoa have a proper circulation ; for there rises
and falls in the cavity of their body a liquid, which is usually clear, and
•often contains round and colorless corpuscles. This rises even to the end
of the cavity of the tentacles, and then returns into that of the body
generally. In the colonial Polyps, these currents, by traversing the canals
of the corallutn, thereby pass from one animal to another. This movement
is caused by ciliated epithelium, which, as we have just seen, lines all the
cavities of these animals.

With the Bryozoa, the cavity of whose stomach does not communicate
with that of the body, these currents are continuous, regular, and have a
definite direction. But with the Anthozoa they are changed by the
reciprocal action through the stomachic orifices of the liquids of the
stomach and cavity of the body. These currents are perceived in the
arms, even when the cavities of these organs open directly into the
stomach. (1)

§ 41.

Nothing can yet be positively said as to the nature of this circulating liquid,
for it is still doubtful whether this whole phenomenon should be regarded
as an aqueous or a sanguineous circulation. If we refer to the fact that the
Anthozoa can introduce water into the system through the apertures of the
stomach, it should be admitted that this system has an aqueous character,
performing, perhaps, the function of an internal respiratory apparatus,

given off from the eight principal longitudinal
vessels numerous lateral branches, which anasto-
mose frequently in the canals of the corallum, and
finally form a capillary net-work. The white,
semi-transparent corpuscles contained in thin
blood have, according to Will, a diameter of
about 1-1200 of an inch, and out of the vessels
have a globular aspect. According to this same
observer, there is a similar vascular system in
Actinia .*

1 The circulation in question has been observed
by many investigators. Trembley (Mem. pour
servir d l’Histoire des Polyps, p. 219) has per-
ceived it in Plumatella cristata. Dumortier
(Mem. sur l’Anat. et la Physiol, des Polypes, p. 47)
has confirmed this observation. Cavoiini (see his
Memoir on the Anthozoa, p. 56, 87) has seen it in
the tubes of several Sertularina. There are various
opinions as to the cause of these currents. Gruit-
huisen (Isis. 1828, p. 506) studied them in the
arms of Hydra , and regarded them due to a com-
munication with a circular vessel surrounding the
mouth. But, according to the observations of
Meyen ( Brown's Miscellaneous Botanical writings,
IV. p. 490), of Ehrenberg (Mittheil. aus. d. Ver-
handl. d. Gesellsch. naturf. Freunde z. Berlin,
1836, p. 27) and myself, the cavities of the arms
open directly into the stomach.

The movements of the liquid in the arms of Hydra
are due not only to the general contractions of the
body, as Gruithuisen and Meyen have supposed,
but also to the cilia covering these parts. This

* [§39, note 1.] Subsequent researches have
failed to detect any true circulatory system with the
real Polyps, and there now can be but little doubt
that no such system exists. As with the Acalephs,

was first pointed out by Grant (The new Edinb.
Phil. Jour. 1827, p. 107 ; or Outl. of Comp. Anat.
1841, p. 430), who observed these currents in
F lustra, Lobular ia, Virgularia and Pennatula.
Nordmann, who has examined this circulation in
the body and tentdteles of Alcyonella diap liana,
and Plumatella campanulata, and other Bryozoa,
did not find any cilia, lie compared the currents
to those seen in the joints of Ohara (Microg.
Beitrag II. p. 75, orObser. sur la Faune Pontique,
p. 709) I feel positive about the presence of cilia
in the body of Cristatella mirabilis and Alcyo-
nella stagnorum. Lister has carefully described
this circulation with Tubular ia, Serlularia and
Campanularia ; and finding no adequate cause,
has likened it to that of Chara (Phil. Trans. 1834,
p. 366, et seq.). Ehrenberg (Abhandl. d. Berl.
Akad. 1832, p. 299) and Lovin ( Wiegmann's
Arch. 1837, I. p. 254) attribute these currents in
Sertularia and Campanularia to a peristaltic
movement of the canals of the body ; which, how-
ever, Van Beneden (M6m. sur les Cam pan. loc.
cit. p. 18) has been unable to see in these Polyps.
Erdl ( Muller's Arch. 1841, p. 426) attributes it,
in Veretillum cynomorium, to cilia; and Will
( Froriep's neue Notizen, 1843, No. 599, p. 69) has
found all the cavities of the body and corallum of
Alcyonium palmatum lined with cilia. It is,
moreover, certain that the currents observed by
Erdl ( Muller's Arch. 1841, p. 428) and Dumor-
tier (Mem. loc. cit. p. 52) in the tentacles of
Actinia are due to ciliary action.

their nutritive and digestive systems are combined;
and, as with them also, the circulating, nutritive
liquid is chyme. See also Dana loc. cit. p. 35.
— Ed.

§41.

THE POLYPI.

49

while the tentacles, in the cavities of which are regular currents, serve as
external organs of respiration, similar to branchiae.

But, if we regard the whole as a true circulation, the contained liquid
with its corpuscles will be analogous to blood. But this view is opposed
by the fact that, with A Icyonium, with Actinia , and perhaps many other
Polyps, there is a true vascular sanguineous system. a)

We ought, therefore, to compare the liquid in question to chyle, which
passes from the stomach to the general cavity of the body, in the Bryozoa
by exosmose, but in the Anthozoa by the orifices of the stomach.®

The opinion that these currents form a vascular system, moreover, is not
reconcilable with the fact that the Anthozoa can at will empty the contents
of their stomach into it, or in the same way shut off from it the water.

AYe are obliged, then, to regard all these cavities as constituting a
vascular aqueous system, performing a respiratory function, by which,
in the Anthozoa, all the internal parts are constantly bathed with fresh
water. This renewal of water is effected by its alternate ingress and
egress through the stomach,® during which chyle-corpuscles could easily,
by being mixed with water, be carried into this aqueous system.

With the Bryozoa, where this system is, without doubt, equally one of
respiration, we shall have to seek for the openings by which this renewal
of water takes place. These are situated near the anus, and place the
cavity of the body in direct communication with tfye external water.*®

1 See § 39, note 1.

2 Ehrenberg and j Lovdn regard the canals of
the corallum of Campanularia and Sertularia as
direct prolongations of the stomach, and designate
them as intestinal tubes, and then’ contents as
chyme.

3 This alternate ingestion and egestion of water
has been positively observed by Lister , Loven and
Van Beneden , in Sertularia and Tubularia.

4 By an opening of this kind, Meyen (Isis 1828,
p. 1228) saw escape the eggs of Alcyonella stag-
nalis , which were free in the cavity of the body.
Van Beneden (Ann. d. Sc. Nat. XIV. 1840, p.
222) declares that he has observed at the base of
the tentacles of Alcyonella a series of orifices,

* [End of § 41.] In this connection should be
mentioned branchia-like organs, described by Dana
(loc. cit. p. 42) with the Zoanthina. A pair of them
is attached to each of the larger lamellae. He
remarks, 4‘ The structure of these organs is such
that we can hardly doubt their branchial nature *,
yet no circulating fluid was detected within them.”
I find no other mention of these parts, except by
Lesueur (Jour. Acad. Nat. Sc. Philad. 1. 183-185,
PI. VIII. fig. 1, 5, 9), who regarded them as of an
hepatic nature. — Ed. k

t l § 41, note 4.] The true nature and relations
of the respiratory and circulatory systems of the
Bryozoa are yet imperfectly understood. There
can be but little doubt that water is by some means
introduced into the general cavity of the body, and
there mingles with the nutritive fluid, which trans-

5

which may be called aquiferous mouths , for by
them the water enters the cavity of the body.
This is perhaps the case with Actinia , also ; for
Rapp (Ueb. die Polypen u. die Aktinien, loc. cit.
p. 47) has here found numerous small orifices
scattered over the whole surface of the body, and
through which are emitted jets of water when the
animal is squeezed, thus showing that they belong
to an aquiferous system. It is quite improbable
that the hollow tentacles of Actinia are open by
an orifice at their apex for the circulation of water,
as many naturalists have supposed. Quatre-
fages (Ann. d. Sc. Nat. XVIII. p. 96) is quite
opposed to this opinion. See also above § 36,
note l.f

udes through the walls of the alimentary canal.
But the apertures for the introduction of this water
have not yet been clearly seen. It is true that
Van Beneden thinks he has found ‘^Bouches aqui-
f£res,” as above mentioned, but their existence
there has not been fully verified, and is even
denied by Allman. At present, therefore, it cannot
be said that the Bryozoa have a true aquiferous
system, like the Anthozoa. The perigastric fluid
is, separated from the water, most probably the
elaborated product of digestion, and the corpuscles
therein contained chyle-corpuscles. Allman's
view, therefore (Report Brit. Assoc. 1850, p. 319),
appears the most correct : “ The perigastric circu-
lation, therefore, unites in itself the triple function
of a chyliferous, sanguiniferous and respiratory
Bystem.” — Ed.

50

THE POLYPI.

$$ 42, 43.

CHAPTER VIII.

ORGANS OF SECRETION.

§ 42.

Nothing like urinary organs have yet been found in Polyps. Perhaps
the borders of the mantles of the cellular Polyps should be regarded as
organs of special secretion, since by them the increase and production of
these cells take place. (1)

CHAPTER IX.

ORGANS OF GENERATION.

§ 43.

Polyps reproduce by gemmation, fissuration, and by eggs.

1. Fissuration is comparatively rare; it takes place nearly always lon-
gitudinally, and the division may or may not be complete. (1>

2. Gemmation is their most common mode of reproduction. The new
individuals may be completely detached, or may remain connected with the
parent corallum.

a : In gemmation, complete separation of the young individual is, on
the whole, rare. It is best known in Hydra, with which the buds
always appear upon a certain part of the body, — that is, at its union with
the foot.® A bud of this kind consists always of a simple fold of the wall
of the stomach and the skin, so that the stomach of the young individual
is in direct communication with that of the parent, and the chyme can pass
freely from one to the other. When the foot of this new being has acquired
a proper development, it is completely detached at its inferior extrem-
ity-

b : Gemmation without separation of the new beings is quite common
with Polyps, and occurs with very various modifications. The buds are
formed sometimes upon the sides, sometimes upon the base of the body.
In the first case, the coralla have a dendroid aspect ; in the second, they
are more lamelliform, spherical or lapidescent. These variations are not
limited to certain genera or species, being often due to external influences,

1 The calcareous tubes of Tubipord , and the
corneous ones of the Sertularina and other Bryozoa,
are, without doubt, secreted by the border of the
mantle, as is true of the shells of mollusks.

1 According to Roesel (Insektenbelust. III. p.
504, 525. Taf. LXXXIII. fig. 3\ fissuration takes
place transversely with Hydra. Longitudinal
fissuration is principally observed with the Madre-
porina. When it is complete the cells of the coral-
lum are definitely limited, as in Astraea , Faviay

and Caryophyllia ; but, when incomplete, the cells
are branched, tabulated, and of irregular contour,
as in Agaricia , Maeandrinay and' Monlicularia ,
&c.

2. Roesel(\ oc. cit. III. Taf. LXXXV. fig. 2, 3, 5,
Taf. LXXXV I. and LXXXVIII. fig. g. h. and Taf.
LXXXIX. fig. 4). The exceptions to this rule,
which are sometimes observed, are probably due
to lesions of an accidental nature.

§§ 44, 45.

THE POLYPI.

51

and especially the nature of the soil upon which the colony may have been
fixed.* ®

§ 44,

3. It is probable that all Polyps reproduce by eggs. This requires two
kinds of organs, one to produce the egg, the other the semen. Both kinds,
ovary and testicle, have already been described in many species.

Their distribution is quite varied. In some, the sexes are united in the
same individual, (1> in others they are distinct;® with the colonial polyps
the sexes are separate, and each colony® may be composed of individuals
which are androgynous, or those of one sex alone.®

Some species are sexless, and remain so ; but they produce by gemmation
individuals of a particular character, which have sexual organs.® These
last, which have usually either a campanulate or discoid form, are separated
from the corallum often before the sexual organs have been formed, and
which they do not acquire until an advanced period of their lives. During
this time they swim freely about, like the pulmograde Acalephae,® for
which, as well as for young Polyps, they are often taken.®

§45.

That the relations just described really exist, may be learned from the
following facts : In Coryne echinataani vulgaris, there are formed at their
base, quadrangular and campanulate individuals, which lay numerous
eggs.® In like manner also, ovigerous capsules are formed about the base
of Syncoryne ramosa .(2) In Coryne fritillaria ,<3) the new individuals are
completely detached and swim freely about, closely resembling Medusae.
In this condition they are developed, and their eggs come to maturity.®

3 Esckara and Flustra have a lamellated form
when fixed to stones, shells, or the broad leaves of
Algae ; but are tubular when attached to the
stems of plants. Alcyonella stag norum under-
goes similar changes in the form of its corallum.
It divides in a regular dichotomous manner
( Eichhorn , Beitr. zur Naturgesch. d. kleinsten
Thiere. Tat. IV.-, alsoAoese/, loc. cit. Taf. LXXIII.
and LXXIV.), and in this form has been described
under the name of PLumatelta camparuulata by
Lamarck. But when a colony of these Polyps
is fixed upon a stone or a sunken root, they com-
mence to be developed in a dichotomous manner.
But afterwards they become lapidescent by the
branches of both modes interlacing each other. As
the mass becomes more voluminous and dense, the
tubes of the dead generation support those of the'
living. (See Lamouroux , Exposit. method, dts
Genres de l’ordre des Polypiers, PI. LXXVI. fig.
5.) Under this form this Polyp has received the
name of Alcyonella stagnorum (see Raspail ,
Hist. Nat. de l’Alcyonelle fiuviatilehf

1 Hydra.

2 Actinia. X

3 Alcyonella.

* [End of § 43.] For a full account of the
reproductive process with Polyps, and the most
philosophical exposition of the relations of gem-
mation and its analogies and affinities with other
developmental processes, see Dana, loc. cit. p. 85.
No abstract can be given of such a work. — Ed.

t [§ 43, note 3., For full details of the gemmi-
parous mode of reproduction with the Bryozoa,
see Van Beneden (Recherch. sur Forganis. des

4 According to Erdl (Froriep's neue Notizen,
1839, No. 249, p. 101) the coralla of Veretillum
cynomorium and Alcyonium have always either
male or female individuals alone. Krohn has
perceived the same of Sertularia (Midler's Arch.

1843, p. 181).

5 Coryne , Syncoryne and Campanularia.

0‘ Coryne and Campanularia.

7 Very striking, at least, is the resemblance of
Van Beneden's (M£m. loc. cit. pi. II.) figure of a
free female of Campanularia gelatinosa and those
of Sars (Beskrivelser. loc. cit. p. 28, Taf. VI. fig.
14) of small Acalephae, named by him Cytaeis
octopunctata, and by Will (Horae tergestiuae,

1844, p. 68, Taf. II. fig. 5) as Cytaeis polystyla.

1 R. Wagner. Isis, 1833, p. 256, Taf. XI. 5 also
leones zoot. Tab. XXXIV. fig. 16.

2 Lowin. Wiegmann's Archiv. 1837, 1. p. 321,
Taf. VI. fig. 19-25.

3 Steenstrup. Ueber d. Generationswechsel, p.
20, Taf. I. fig. 41-47.

4 According to Sars (Beskrivelser. loc. cit. p. 6,
Taf. I. fig. 3), these remarks are also true of Co-
rymorpha nutans.

Laguncula, &c., Mem. Acad. Iloyale de Bruxelles,
XVIII. ; also, Recherch. sur l’Anat. la Physiol,
et le developpement des Bryozoaires, &c. Ibid.
XIX.). See also Allman, Report Brit. Assoc. 1850,
p. 320. — Ed.

X ( § 44, note 2.] According to my own obser-
vations, the Actiniae have both individuals which
are hermaphrodites and those of one sex aloue.
— Ed.

52

THE POLYPI.

§46.

The Campanulariae and Sertvlariae produce at the end of their pedicle
and branches elongated sexless individuals. But in the angles of these
branches cells of another form, and containing many sphei’ical individuals,
are developed. In these last sexual organs are formed, which, in Campan-
ularia geniculata, occurs without a separation of the new individuals from
the corallum, while in Campanularia gelatinosa it is after detachment has
taken place.®

§ 46.

In the eggs of polyps both a germinative vesicle and dot may often be
seen. Frequently, however, both disappear at a very early period. The
envelopes of the egg are usually of a simple/1’ though sometimes of a
complicated structure. The spermatic particles are very active, and in
some species are filamentoid, in others composed of a solid body or head,
to which is appended a very delicate tail. Water does not appear to affect
either their form or motion.®

5 According to Krohn (Muller's Arch. 1843, p.
174), it is probable that in Campanularia and Ser-
tularia both sexes are developed in this way.
From Ellis ’ description of Campanularia dicho-
toma (Essai sur PHisfc. Nat. des Corallines, p.
116, pi. XXXVIII. fig. 3), it may be concluded
that the females, mistaken by these naturalists for
eggs, separate in this way from the corallum.
Me yen (Nov. Act. physico-medica. XVI. Suppl. I.
1834, p. 195, Tab. XXX. fig. 3, 4) has also taken
the medusoid females of this species for spawn.

[Additional note to § 45.] The series of those
polyps, the sexless (nurse-like) individuals of
which produce self-dependent, medusa-like young,
has been increased by several more recent re-
searches. See Van Reneden , Rech. sur l’embryol.
d. Tubulaires, 1844, pi. I. IV. (Tubularia and
Eudendrium) •, Sars, Faun, littoral. Norveg. p. 7,
Tab. I. (Podocoryna and Perigonimus) ; Du-
jardin , Ann. d. Sc. Nat. IV 1845, p. 257, pi. XIV.
XV. (various Ilydrina). It is true .that the de-
velopment of the genital organs has not been ob-
served in these medusa-like individuals 5 but they
have indeed in the medusiform individuals of Syn-
coryne ramosa and Coryne fritillaria, and there-
fore it may be proper to infer that the same is true
of other Hydrina and Sertularina. If it is cor-
rect to regard as the perfect state that in which
the individuals resemble Meduste, and as the im-
perfect state that in which they are polypoid, then
should we, as has been done already by many, re-
move these animals from the class of the Polypi,
and place them with the Acalephae.*

1 In most Anthozoa. Eggs of this kind, belong-
ing to Actinia , Coryne and Veretillum , have
been figured by Wagner (Wiegmann's Arch.
1835, 1. Taf. III. fig. 2 ; Prod. Ilist. Gener. hom.
atque anim. Tab. I. fig. 1, and leones zoot. Tab.
XXXIV. fig. 5, 17, 23).

2 With most Bryozoa the spermatic particles
are filamentous. Both from their size and their

* [ End of additional note to § 45.] The remark-
able relations here spoken of, and the conjectures
as to the real zoological nature of the animals in
question, have been pretty satisfactorily cleared up
by the recent researches of Agassiz. He has shown
that the Hydroid Polyps are not simply a lower
form of stemmed animals, producing at a given
period more highly-organized Medusae, but that
they are themselves, by their structure, real Medu-

motions, they have been taken for parasites.
Kblliker (Beitr. zur Kennt. d. Geschlechtsverhalt.
u. d. Saamen. Fliissigkeit wirbellos. Thiere, p. 41,
Taf. II. fig. 17) has seen the spermatic particles of
a thread-like form, of Flustra carnosa , develop-
ing in cells, and has seen them moving in the cav-
ity of the body. I have seen similar ones in Crista-
tella mirabilis and Plumatella campanulata.
Those which were seen by Farre (Phil. Trans.
1837, p. 403, pi. XXIII. fig. 5, g) in the cavity
of the body of Valckeria cuscuta , and were re-
garded by him as intestinal worms, have an oval
body, to which is attached a delicate tail. Nord-
mann (Faune Pontique loc. cit.) has found those of
Cellar ia avicularia having the same form. Those
of Actinia have also a similar form (see Erdl
Muller's Arch. 1842, p. 301, and Kblliker , loc.
cit. p. 44, fig. 13). One should be careful and not
confound the spermatic particles with the nettling
organs having a similar form 5 and especially as
the development of these last has apparently some
connection with that of the sexual organs (see
Erdl loc. cit. p. 305). According to Kblliker, the
spermatic particles of Alcyonidium gelatinosum
have a lanceolate body, with a hair-like tail (loc.
cit. fig. 10J.

Spermatic particles of a cercaria-form have been
observed by Wagner (Icon. zoot. Tab. XXXIV.
fig. 7, 12) with Veretillum and Hydra ; by Van
Beneden (Rech. sur l’organisat. d. Laguncula,
and Rech. sur l’anat. d. Bryozoaires, pi. V. in the
Nouv. M£m. de Bruxelles, &c. XVIII.), with La-
guncula and Ha/odactylus ; by Rathki (Wieg7
mann's Arch. 1844, I. p. 161, Taf. V. fig. 6) and
Steenstrup (Untersuch. iib. das Vorkommen d.
Hermaphrodit. p. 66, Taf. I. fig. 18, e) with
Coryne ; finally by Kblliker (Nene Denkschr.
VIII. p. 48, fig. 20, 21, 22, 24) with Pennaria ,
Eudendrium and Sertularia. In Crisia , on the
other hand, Kblliker found the spermatic particles
perfectly filiform, f

sae. See Lectures on Comparative Embryology,
1848 5 also Proceed. Amer. Assoc, for the Advance-
ment Sc. 1849 (“ On the Plan of Structure and Ho-
mologies of Radiated Animals”), and Mem. Amer.
Acad. loc. cit. p. 225. — Ed.

t [ § 46, note 2.] I have been able to trace the
development and character of the spermatic par-
ticles of many of the true Polyps and the Bryozoa.
The development occurs in special daughter-cells,

$$ 47, 48.

THE POLYPI.

53

§ 47.

I. With those polyps which are not sexless, and whose alimentary canal
hangs free in the cavity of the body, the sexual organs are situated in this
last. They often escape attention, since they are scarcely at all developed
except at the sexual epoch. Both ovaries and testicles frequently
appear as riband-like bodies, which, being attached by one extremity alone
to the stomach, move freely in the general cavity of the body. Sometimes,
however, they are attached longitudinally by one of their borders, like a
mesentery, the opposite border being free. In other cases, again, they are
attached directly to the sides of the body.

The eggs and spermatic particles pass directly from the sexual organs
into the cavity of the body. In Coralla having individuals of both sexes,
fecundation takes place in the cavities of their bodies, which connect with
each other.® With the others, however, the individuals of which are of
one sex alone, the surrounding water is the medium of fecundation, by
transporting the spermatic particles unaffected to the eggs ; and this being
performed by the aqueous circulation before mentioned, impregnation takes
place in the cavity of the body.

§ 48.*

The variations of the internal genital organs in the different families are
as follows :

1. With the Bryozoa, a riband-like ovary and testicle are suspended
from the extremity of the stomach. In these organs are developed only
two to four eggs or fasciculi of spermatic particles, from cells arranged like
a string of pearls.®

The eggs, of which the germinative vesicle and dot disappear at a very
early period, are detached from the ovary before their shell is well formed,,
and are set in motion by the cilia of the cavity of the body. Usually they
are flattened, and at first enveloped by a thin and colorless membrane,
which soon becomes thicker and darker, and has upon its borders a clear,

1 With Tendra zostericola, which is allied to
Flustra , the Polyps are contained in cells closely
bound to each other. But the cells of the males
communicate with those of the females by an open-
ing, through which the spermatic particles pass
into the cavity of the body of the female (see
Nordmann , Ann. d. Sc. Nat. XI. 1839, p. 191).

and the particles themselves are the metamor-
phosed nuclei of these cells, exactly as in other and
higher animals. They have invariably, as far as I
am acquainted, a cercaria-form consisting of a solid
head, to which is attached a most delicate tail.
The shape of this head, when studied carefully with
the best powers, presents differences of zoological
import. Sometimes it is pyriform ( Tubularia ,
Actinia ), sometimes conical ( Astrangia ), while
among the Bryozoa it is long-oblong with Alcyo-
nclla. I cannot therefore agree with Kdlliker
(Cyclop. Anat. Art. Semen. 1849, p. 497) as to the
mode of development of these particles with these
animals. — Ed.

1 See. for Alcyonella stagnorum , Meycn (Isis,
1828, Taf. XIV. fig. 1), for Plumatella cristata ,
IJumortier (loc. cit. pi. I. fig. 3, u, u) and for
Cellaria avicularia, Nordmann (Obs. sur la
Faune Pontique, p. 679, fig. 4, A. n).f

* [§ 48.] In an emendatory note at the end of
the volume, the author remarks: “Sections 21 and
3d of this paragraph should be omitted, since the
genital organs, with all the Anthozoa, are attached
on the internal surface of the visceral cavity. See
Frey and Lcuckart. Beitr. &c. p. 13.” I have,
however, allowed them to remain, for the sake of
their notes. — Ed.

t [ § 48, note 1.] My own researches in 1851
have shown me that with Alcyonella the sexes are
separate. The testicles and ovaries consist of pedun-
culated sacs, closed at first, but which are rup-
tured on the mature development of their contents.
— Ed.

5*

54

THE POLYPI.

§§ 49, 50.

transparent ring. In Alcyonella and Plumatella, the eggs are of an oval
shape, and of a dark-brown color. In Cristate/la mirabilis , Dal. ( Crista -
tella mucedo, Cuv.), they are lenticular and clear brown, and have this re-
markable peculiarity : (2) 3 4 Upon both sides of the encompassing ring are a
number of double-pointed hooks, which, at first, are imbedded in a gela-
tinous substance ; but as this last is dissolved by water, they become free,
and adhere to plants and other bodies.®

2. With many Anthozoa, having a cavity of the body, the sexual or-
gans are attached in the form of bands along the external face of the
stomach. These are numerous, and during the epoch of reproduction their
free borders are often plicated, and have a botryoidal aspect. This form
is quite apparent in the Actiniae, where these organs are contained in sep-
arate chambers of the cavity of the body.® The same is true of the Ed-
wardsiae .(5) 6 7 8 9 With Veretillum (G) and Alcyonium {7) these organs form mesen-
teric divisions which descend deep into the cavity of the body.

3. In Alcxyonidium elegans (8! and Tubipora musica (9) these organs are
attached to the internal surface of the cavity of the body, and have a pli-
cated mesenteric form.(l0)

§49.

The laying of the eggs takes place in different ways with those Polyps
having internal sexual organs. With the Bryozoa it probably occurs
through the openings near the anus.® With the Anthozoa, however, they
pass into the stomach through its abdominal orifices, and thence are
ejected through the mouth. In the viviparous Actinia, the young, devel-
oped at the base of the stomach, are expelled in the same manner.®

§50.

II. Many Anthozoa, which have no general cavity of the body, have
external sexual organs. This is especially true of Hydra, where in the

2 Raspail; loc. cit. pi. XII. fig. 10-12, pi. XIV.
fig. 4-S, and pi. XV. fig. 5.

3 Turpin and Gervais , Ann. des Sc. Nat. VII.
1837, pi. III. A. fig. 2-4, and pi. IV. A. fig. 1-6.

4 Wagner. Wiegmann's Arch. 1835, 1. Taf. III.
fig. 1 ; also leones zoot. Taf. XXXIV. fig. 22.

5 Quatrefages. Ann. d. Sc. Nat. loc. cit. pi. I.
fig. 7, and pi. II. fig. 10.

6 Carus and Otto. Eriauterungstafeln, Heft. IV.
Taf. I. fig. 19 *, also Wagner , leones zoot. Taf.
XXXIV. fig. 2.

7 Milne Edwards. Ann. d. Sc. Nat. loc. cit. pi.
XIV. fig. 4 j pi. XV. fig. 6, 8, and pi. XVI. fig.
3-5.

8 Ibid. p. 329, pi. XII. fig. 3, pi. XIII. fig. 2, 7.

9 Rijmer Jones. Outlines, loc. cit. p. 36, fig. 9,
after Lamouroux.

10 K olliker’s observation upon the sexual organs

* [ § 48, note 10. J With the Actinina, some of
the lamellae which partition off the visceral cavity
are margined each by a white, capillary, convolut-
ed cord. It is attached to the lamellae by a thin,
mesentery-like membrane. These cords are the
testicles. Between the spermatic lamellae are oth-
ers similarly arranged, which are the ovarian , on

of Alcyonidium gelatinosum , Johnst. ( Halo -
dactylus diaphanus of Farre), is quite remarka-
ble; for he found them wanting in the isolated in-
dividuals, but scattered here and there, in the form
of small round sacs, in the fleshy substance of the
corallum — some being ovaries, others testicles.
But he is in doubt whether or not their contents
are emptied into the cavity of the hotly or upon the
outer surfaces (Beitr. loc. cit. p. 46).*

1 See, for Alcyonella stagnorum , Meyen (Isis,

1828, p. 1228).

2 Rathkt has often found spawn in the stom-
ach of Actinia (Iteise Bernerk. aus Taurien, zur
Morph. 1837, p. 10, and Beitr. zur vergleich.
Anat. u. Physiol, in the neuesten Schrift. d. na-
turf. Gesellsch. zu Danzig, HI. lift. IV. 1843, p.
112).

which are situated the ovaries. With the Zoanthi-
dae the relations are of the same general nature;
but with the Tubipora, Dana found six spermatic
to two ovarian lamellae. See Dana, loc. cit. p. 43,
pi. XXX. fig. 3, b, c, d, e, f, and pi. LIX. fig. 1, b.
— Ed.

THE POLYPI.

§50.

55

same individual during the time of heat both ovaries and testicles are de-
veloped upon the external surface of the body.

In the place where the eggs are to appear, (1> the transparent and color-
less skin rises in the form of swellings, under which the vitelline mass
gradually forms. These end each in the form of an excrescence, which,
being constricted at its base and rounded, has the shape of an egg. At
the point of constriction there is formed from the body of the Polyp a
kind of cupel, in the cavity of which the vitellus rests by a small portion
of its surface ; at this point the skin becomes thin, and ultimately appears
like an arachnoid membrane enveloping the egg. In this last neither a
germinative vesicle nor dot has been discovered. Its separation is preceded
by a thinning of its surrounding membrane, after which the vitellus is im-
mediately clothed by a gelatinous substance. In Hydra vulgaris its whole
circumference is covered by obtuse prolongations of this kind, which, after
an increase in length, divide, each once or more, at their extremity, and so
present a dentated appearance.

The arachnoid membrane finally bursting, the detached egg becomes
fixed to some body, whilst the gelatinous coat entirely disappears. This
is equally true of Hydra viridis, with the exception that here the vitelline
prolongations are very short and compact.®

In these same individuals testicles are developed also. Between the
base of the tentacles and the place of the appearance of the egg, there
are developed small conical prominences, on the apex of which is a papil-
la. This has an orifice which leads into an internal cellular cavity. This
is the real testicle, wherein are found spermatic particles composed of a
body, or head, to which is attached a very movable tail. These particles
easily escape through the orifice, and circulate in the water surrounding
the Polyps filled with eggs.® The number of these testicles in a single
individual is not definite. (4) *

1 In the arra-polyps, gemmation always pre-
cedes propagation by eggs.

2 The eggs of Hydra were long ago observed by
Bernhard Jussieu (Abhandl. d. schwed. Akad.
1746, VIII. p. 211). But afterwards they were
regarded as exanthemata of this animal (see Roe -
sel? Insektenbelust. Th.III. p. 500, Taf. LXXXIII.
fig. 1, 2). Their true nature was lately first
pointed out by Ehrenberg (Abhandl. d. Berliner
Akad. 1336, p. 115, Taf. II.).

3 The testicles of Hydra were known to the elder
naturalists, but were taken for an eruptive disease
( Trembley Abhandl. zur Geschicht. einer Polype-
nart, p. 264, Taf. X. fig. 4, and Roesel , loc. cit. p.
602, Taf. LXXXIII. fig. 4). Latterly this same
error has been continued ( Laurent in Froriep's
neuen Notizen, 1842, No. 513, p. 104). To Ehren-
berg is due the first description of their true nature
(Mettheil. aus den Verhandl. d. Gesellsch. naturf.
Freunde in Berlin, 1838, p. 14).

* [At end of § 50.] The so-called ova, mentioned
above in the text, may be justly questioned as be-
ing true ova, for we know of no real ova which do
not contain a germinative vesicle. Then, again,
simple oval masses of cells as they are, they would
exactly resemble the bud-like eggs of Aphides, and
the “ hibernating eggs ” of Daplinia and some of
the Rotatoria, all of which are properly gemmae,
and do not require the agency of the spermatic

4 Wagner , leones zoot. Tab. XXXIV. fig. 10,
b, b. In Hydra vulgaris I have counted fifteen
testicles 5 another individual had seven eggs and
eleven testicles j and a third, four eggs and twelve
testicles.

[Additional note to § 50.] Other examples of
Anthozoa having external genital organs in the
form of egg or sperm capsules have been observed
by Van Beneden (Rech. sur l’embryog. d Tubul.
pi. V. VI.), Rathlcd ( Wiegmann's Arch. 1844, I.
Taf. V.), and Sars (Faun, littoral. Norveg. p. 7,
Tab. II.), with IJydractinia, Coryne and Podo-
coryne. See also the facts collected by Frey and
Leuckart (Beitr. &c. p. 28). These egg or
sperm capsules may, moreover, be regarded as
imperfect male or female individuals, and then the
porters of these capsules may be considered, being
sexless individuals like those mentioned in § 45,
in the category of nurse-like generations which, af-
ter a more or less complete development, produce
generations with sex.

particles for their development. It is also worthy
of remark, in this connection, that these ova sprout
from the same part of the body in which eggs are
developed. Thomson , however (Edinb. New

Philos. Jour. 1847, p. 287), speaks of having ob-
served the granular mass contained within these
so-called eggs divide and subdivide like a proper
vitellus, and this while still within the capsule, and
attached to the parent animal. This doe3 not

56

THE POLYPI.

§§ 51, 52.

§51.

III. There are Polyp-colonies which contain two kinds of individuals,
those which are sexless, and those having sexual organs only at certain
epochs. These last are campanulate or inedusoid, and their sexual organs
are developed in various parts of their body.

In Coryne (1) and Syncoryne,{'2) the eggs appear upon the external sur-
face of the stomach, then fall into the cavity of the mantle, through the
openings on the border of which they escape into the water. In the medu-
soid individuals of Coryne fritillaria and Corymorpha nutans , the sexual
organs appear to be formed in the angles of the borders of the disc,® and
in Campanularia in the disc itself. *

§ 52.

As to the embryonic developments of Polyps, it is. probable that in a
great number (perhaps all) there is a metamorphosis.

The development commences by the usual segmentation of the vitel-
lus,(1) by which it is ultimately converted into an ovoid, contractile body;
this turns upon its longitudinal axis by means of cilia, with which it is en-
tirely covered, swimming about like many Infusoria. These embryos,
often developed in the mother, have sometimes been taken for swimming
eggs.® Afterwards they attach themselves to some body, and usually lose
their cilia ; the free extremity of their body opens, allowing the escape of
the Polyp, which, in the mean while, has been developed in the interior,
with its arms in front. Many of the Polyps thus produced multiply by
gemmation, and thus become the foundation of new Polyp-colonies.®

1 fVdgner (Isis 1833, Taf. XI. fig. 8).

2 Loven ( Wiesmann's Archiv. 1837, I. Taf.
VI. fig. 19, 20).

3 Steenstrup , Ueber d. Generationswechsel, p.
23, 24.

1 It is indeed singular that with Hydra the divi-
sion of the vitellus takes place before the eggs are
either detached from the body, or are surrounded
by a dentated envelope. I do not yet know at what
epoch the development of the embryo commences,
for I have never seen the young come forth. It i3
impossible for me to say whether or not these
Polyps experience a metamorphosis. Pallas (Ka-
rakteristik d. Thierpflanzen p. 53) has seen the
young Polyps come forth from the egg, but he gives
no description. Laurent, also, only says that the
young animal escapes formed from the egg, with-
out describing the embryo (Froriep's neue Notizen,
No. 513, pi. 101). The segmentation of the vitellus
has been observed by Van Beneden in the eggs of
Pedicellina. See his Rech. sur l’anat. d. Bryo-
zoaires (suite) loc. cit. XIX. p. 18, pi. II.

2 As would be inferred from his description, Cav-
olini (loc. oit. p. 47, 50, Taf. IV. fig. 7-10 and 13-
15) has observed similar embryos to those of Gor-
gonia and Madrepora. Ilis descriptions of various
eggs of Sertularia leave no doubt that they also

make the matter any more clear ; for, even admit-
ting that they are proper ova, it is difficult to con-
ceive how the impregnation (of which the segment-
ation for a definite result is the sequela) could take
place while the ova are thus buried in the capsules.

The subject requires further research. See also
Steenstrup , Untersuch. ub. Hermaphroditismus, p.

were embryos (Ibid. p. 56, 80 et seq.). Grant also
has taken for eggs the contractile, ovoid embryos
of Lobularia digitata , which he has seen issue
from the mouth of this animal ( Froriep's Notizen
1823, No. 440, p. 340). Meyen has well described
and figured the ciliated epithelium of those of Al-
cyonella stagnorum (Isis 1828, p. 1228, Taf.
XIV. fig. 4, 5). Lovtn has observed the elon-
gated embryos of Campanularia genic alata, and
has taken the division of the vitellus for a sponta-
neous fissuration of the embryos (Wiegmann's
Archiv. 1837, I. p. 260, Taf VI. fig. 13, 14). Ac-
cording to Rathlce , who has seen movable lenticu-
lar embryos in the stomachs of Actinia, these
polyps experience a metamorphosis ( Reise Be-
merk. aus Taurien zur Morph, p. 10, Taf. 1, fig.
12).

3 This metamorphosis has already been observed
by Cavolini (loc. cit. p. 261, Taf. VI. fig. 7) with
Sertularia racemosa , and more lately by Low&n
(loc. cit. p. 261, Taf. VI. fig. 15-17) with Campa-
nularia genic ulala. There are always developed
in the interior of the embryos of Alcyonella stag-
norum two Polyps, even before the first have es-
caped from the egg ; when the escaped embryo has
become fixed, its skin bursts, and the Polyps escape,
but are able to return again as into a mouth.

116, and Hancock , Ann. Nat. Hist. 1850, Y. p.
282. — Ed.

* [End of § 51. | See Schultze (Muller's Arch.
1850, p. 57), who has found with Campanularia
seminal capsules corresponding to those for egg-
capsules pointed out by Lovdn ( loc. cit.). — Ed.

§52.

THE POLYPI.

57

This metamorphosis is completed when the skin is
covered by a brown and solid layer, and new indi-
viduals are developed by gemmation from the two
Polyps (See Meyen , Isis, loc. cit.). I have seen
the development of the coralla of Cristatella mi-
rabilis and PlumateUa campanulata occur in
the same way. With the Cristatellae, gemmae of
new Polyps are often seen to arise from the skin,
even after the escape of the two Polyps, and before
the young colony has become at all fixed. At this
epoch of development these Polyps have been taken
by Cuvier for a distinct species, and called Crista-
tella mucedo. See Roesel , loc. cit. p. 559, Taf.

* [§ 52, note 3.] The embryonic development
of the Bryozoa has been carefully wrought out by
Van Beneden. See Recherch. sur les Bryozoaires,

XCI. •, and Turpin, Ann. d. Sc. Nat. VII. 1837, p„
65, pi. II. and III.

Infusoria-like embryos have been observed also
by Steenstrup (Untersuch. loc. cit. p. 66, Taf. I. fig.
21) with Coryne squamata , and by Sars (Faun,
littoral. Norveg. p. 7, Tab. II. fig. 7-11) with Po -
docoryna carnea. The round eggs moving about
by means of cilia, which Reid (Ann. of Nat. Hist.
XVI. p. 392, 397, pi. XII. fig. 9, 13) has observed
in the visceral cavity of Pedicellina echinata ,
and in special capsules with F lustra avicularis,
were probably embryos also.*

&c., M6m. Acad. Bruxelles. XIX. See also All-
man, Report, loc. cit. 1850, p. 322 — Ed.

BOOK THIRD.

ACALEPHAE.

CLASSIFICATION.

§ 53.

•

The body of Acalephae is composed of a transparent, gelatinous sub-
stance, quite resembling the Corpus vitreum of the eyes of vertebrata. By
desiccation it almost entirely disappears, there remaining only a dry cel-
lular tissue, by which the form of the animal is imperfectly preserved.
These animals swim freely in the sea after having attained their develop-
ment.

In the arrangement of their organs in ray-like processes radiating from
a common centre or a longitudinal axis, and where also is situated the
digestive apparatus, the quaternary system prevails. Copulatory organs
are always wanting. The classification is based, according to the system
of Eschscholtz, upon difference of external form, and upon the structure of
their digestive and locomotive organs.

ORDER I. SIPHONOPHORA.

They take in their food by means of numerous tubes, which exist in
place of a stomach. Locomotion is aided, generally, by certain cartilagi-
nous capsules.

Family: Dipiiyidae.

Genera : Diphyes, Ersaea.

Family : Physophoridae.
Genera : Physophora, Stephanomia.

Family: Physalidae.

Genus : Physalia.

Family : Velellidae.
Genera : Rrtaria , Velella , Porpita.

§53.

THE ACALEPHAE.

59

ORDER II. DISCOPHORA.

They have a simple central stomach, and move by means of discoid or
campauulate contractions of their body.

Family : Aequorina.

Genera : Aequorea , Polyxenia.

Family : Oceanidae.

Genera : Oceania , Cytaeis, Thaumantias.

Family : Geryonidae.

Genus : Geryonia.

Family : Rhizostomidae.

Genera : Cephea, Cassiopea, Rhizostomum.

Family : Medtjsidae.

Genera : Pelagia, Cyanea, Chrysaora, Medusa, Aurelia, Ephyra, Slhe'no-

nia.

ORDER III. CTENOPHORA.

Their mouth and stomach is simple and central, and they move by means
of cilia arranged in longitudinal rows.

Family: Beroidae.

Genera : Beroe, Lesueuria, Medea.

Family : Mnemiadae.

Genus : Euckaris.

Family : Callianiuidae.

Genera: Cydippe, Cestum.

BIBLIOGRAPHY.

Eschscholtz. System der Acajeplien. Berlin, 1829.

Lesson. Histoire naturelle des Zoophytes. Acalephes. Paris, 1843.

Will. Horae tergestinae oder Besehreibung und Anatomie der im
Herbste, 1843, bei Triest, beobachteten Acalephen. Leipzig, 1844.

Ehrenierg. Ueber die Acalephen des rothen Meeres und den Organis-
mus der Medusen der Ostsee, in the Abhandlungen der Berl. Akad. 1835.

Mertens. Beobachtungen und Untersuchungen iiber die beroeartigen
Acalephen, in the Memoires de l’Academie des Sciences de St. Peters-
burg, 6me series, Tom. II. 1833, p. 479. Also, in Isis, 1836, p. oil.

Brandt. Ausfiirliche Besehreibung der von C. H. Mertens auf seiner
Weltumsegelung beobachteten Schirmquallen, nebst allgemeinen Bemerkung-

60 THE ACALEPIIAE. § 54.

en iiber clie Schirmquallen iiberhaupt, in the Mem. de l’Acad. des Sc. de
St. Petersburg, 6 ser. Tom. IV. 1838, p. 239.

Milne Edwards. Observations sur divers Acalephes, in the Ann. des
Sc. Nat. 2de Ser. Zoologie. Tom. XVI. 1841, p. 194.

ADDITIONAL BIBLIOGRAPHY.

Forbes. A monograph of the British naked-eyed Medusae, with figures
of all the species. London, Ray Society, 1848. Contains 'many anatom-
ical details.

Agassiz. Contributions to the Natural History of the Acalephae of
North America.

Part I. — On the Naked-eyed Medusae of the shores of Massachusetts,
in their perfect state of development.

Part II. — On the Beroid Medusae of the shores of Massachusetts, in
their perfect state of development. See the Mem. Amer. Acad. Arts and
Sc. vol. IV. 1850.

Also, Twelve Lectures on Comparative Embryology, delivered before
the Lowell Institute, Boston, 1848—49.

Busch. Beobachtungen fiber Anatomie und Entwickelung einiger wir-
bellosen Seetniere. Berlin, 1851.

[The above are among the most important larger works; but see, also,
many papers of great value, to which I have referred in my notes. — Edi-
tor.]

CHAPTER I.

SKIN AND CUTANEOUS SKELETON.

§ 54.

Generally, the body of the Acalephae is of a gelatinous substance, com-
posed of polyhedral cells. In some species certain parts of the body have
a cartilaginous hardness, but it is only in a few that there is found a carti-
laginous or calcareous nucleus, comparable to a rudimentary skeleton.

With the Diphyidae a large portion of the body has a cartilaginous
density, and with the Physophoridae it is often surrounded by plates of a
similar nature. The Velellidae have a nuclear skeleton, which in Rata-
ria is a simple, elongated disc; but in Velella this disc, which is horizon-
tal and of an elongated oval form, is surmounted by a vertical crest. The
disc is composed of four pieces joined together by two sutures which cross
each other obliquely. The crest, united to the disc along the whole length
of the two sutures, and resembling the segment of a circle, is composed of
two main pieces, joined in the middle by a third, which is shaped like a
wedge. (l)

The disc situated under the skin of the upper surface of Porpita, and

X Eschscholtz, loc. cit. Taf. XV. ; and Lesson , Acaliphes, loc. cit. PI. XII. fig. 1; also ,Duperrey,
Voyage loc. cit. Zoophytes, No. 6. fig. 1, A. A.

§§ 55, 56,

THE ACALEPHAE.

61

which encloses between its two lamellae numerous aerial canals, is said to
be of a calcareous nature.®

All these discs have upon their surface markings of concentric rings and
diverging rays.

§ 55.

The Acalephae are surrounded by a very delicate epidermis. Upon
various portions of the body, and especially upon the arms, the tentacles,
the prehensile filaments and the cirri, there exist cilia and peculiar net-
tling and prehensile organs. In those species having active irritating prop-
erties the nettling organs are situated in a mass under the epidermis.®

§50.

These nettling organs are generally composed of an oval capsule, con-
taining a spiral filament which is thrown out from the slightest disturb-
ance, and, together with its capsule, is detached from the skin.®

In some. species, there exist in place of these nettling organs others of a
prehensile nature, consisting of an oval capsule in which is a stiff bristle.
These last cause no burning sensation, but are the means by which these
animals attach themselves to contiguous objects in a bur-like manner.
They are situated, grouped in small masses, under the skin of most of the
non-nettling Discophora, and their bristles project upon the cirri situated
upon the border of the disc, upon the tentacles, the arms and the sexual
organs.®

2 Eschscholtz , loc. cit. p. 176, and Lesson , loc.
cit. PI. XII. fig. 3 ; also, Duperrcy , loc. cit. No.
7, fig. 3.

1 Wagener ( Muller's Arch. 1847, p. 183, Taf.
VIII. fig. 4, 5) has described the peculiar hair-
like productions on the sides of Beroe and Cydippe.
They have, near their free extremity, a multitude
of pedunculate small buttons, inserted on a clavate
swelling.

1 Wagner (Icon. zoot. Tab. XXXIII. fig. 8,
10, 11, A. B. 0. and Ueber den Bau der Pelagia
noctiluca, 1841. j also, in Wiegmann's Archiv
1841. Th. I. p. 39) has found in Pelagia noctiluca
that the nettling capsules are situated among the
yiigment cells beneath the epithelium of the disc.
According to this author, Oceania , which has feeble
nettling powers, has these capsules only u^on the
marginal filaments. *

Ekrenberg ( Wiegmann's Archiv 1841, Th. I.
p. 71, Taf. III.) has failed to find these organs upon
the non-nettling disc of Cyanea capillata, although
they are found among their prehensile cirri, which
have irritating power.

With these, as with the hooked organs of Hydra ,
he thought the capsule was detached before the fil-
ament. Will (Ilorse tergest. pp. 62, 65) did not
find these organs in Cepliea , except on the tenta-
cles of the genital organs •, and in Poly xenia only
on the marginal filaments. Kolliker (Beitrage,
loc. cit. p. 41) has seen them also about the gen-
itals of Chrysaora and Aequorea.

The Siphonophora have only the prehensile fila-
ments covered with them. Thus in Stephanomia ,
according to Milne Edwards (Ann. d. Sc. Nat.
XVI. p. 223, PI. VIII. fig. 9), they cover the whole
surface of these last -, while in Physophora , Diph-
yes and Ersaea , they exist only upon their en-
larged portions, according to Philippi ( Muller's
Arch. 1843, p. 62, Taf. V. fig. 9), and Will (loc.
cit. p. 79, 81, Taf. II. fig. 23-25). *

2 Siebold (Beitrage zur Naturgesch. der wirbel-
losen Thiere, 1839, p. 10, 91, Taf. II. fig. 39) ; also,
Ekrenberg (Ueber die Acalephen d. rothen Mee-
res, &c. &c., in the Abhandl. d. Berl. Akad. 1835,
p. 205, Taf. IV-VIII.). He has compared these
prehensile organs to suckers.

According to Milne Edwards (Ann. d. Sc. Nat.
XVI. p. 215), and Will (loc. cit. p. 80, Taf. II. fig.
24), they are found also upon the body of Beroe ,
and at the extremity of the prehensile filaments of
Diphyes and Ersaea.

According to Will, also (loc. cit. p. 51, Taf. I.
fig. 19, A. B.), the prehensile filaments of the Cten-
ophora have two kinds of capsules -, one, which
upon the least touch bursts and discharges a liquid-,
the other, of a somewhat different appearance,
and which contains a delicate, viscous filament.
Similar filaments, he says, are found upon the
warts on the body of Eucharis.

* For these nettling organs and their intimate structure, see my note under § 27, note 1. — Ed.

6

62

THE ACALEPHAE.

$$ 57, 58.

CHAPTER II.

MUSCULAR SYSTEM AND ORGANS OP LOCOMOTION.

§ 57.

Tlie Acalephae have a distinct muscular system. Their contractile sub-
stance is composed of a net-worlc of elongated, slender filaments and
bands ; these, in the utriculoid species, are arranged in a longitudinal and
annular manner, but in those of a discoid and campanulate form they are
disposed in a circular and radiate manner.

In the extremely irritable tentacles and tactile filaments, the longitudi-
nal fibres abound. (1)

Each fibre is smooth when relaxed, but during contraction appears trans-
versely wavy and plicated.®

§58.

The contractile and aerial natatory vesicles, which are found in the Phy-
sophoridae,(1) and the movable lamellae of the Ctenophora, may well be
regarded as accessory organs of locomotion. These last, which are arranged
in rows upon the sides of the animal, and which by some anatomists have
been regarded as respiratory organs, are not simple cutaneous lobes, but are
composed of very long cilia closely united together, and the motion of which
is voluntary with the animal.®

1 Will (loc. cit. p. 48, Taf. I. fig. 11) has observed
in the contractile excrescences of the Eucharis ,
not only circular fibres and numerous longitudinal
muscles, but large transversely-flattened ones,
which were bound together by oblique bands.

2 Will, loc. cit. p. 47, 63, Taf. I. fig. 13, Accord-
ing to Wagner (Ueber den Bau, &c. ; and Icon,
zoot. Tab. XXXIII. fig. 30), the muscles of the
Disoophora have always the transverse striae.

The cartilaginous natatory pieces of the Siphon-
ophora play a completely passive part in the act
of locomotion. The swimming is exclusively per-
formed by the energetic contractions of the mus-
cular membrane which lines their cavity, con-
stituting, therefore, a true natatory sac. See Sars
Faun, littoral. Norveg. p. 42.*

1 Lately, it has been doubted if the Physophor-
idae can sink and rise in the sea by means of their
natatory bladders, because they cannot exhaust the

* [ § 57, note 2.] For the muscular system of the
Acalephae, see also Forbes (loc. cit. p. 3), and
Agassiz (loc. cit. p. 236). This last-named author
has described this system with full details in many
genera. It is much more complex than has hitherto
been supposed, and I must refer for the details
to the memoir in question.

contained air. According to Olfers (Abhandl. d.
Bed. Akad. 1831, p. 157, 165, Taf. I.), there are
two of these bladders in Physalia , one of which
only has an opening. Philippi ( Muller's Arch.
1843, p. 63) has found neither internal nor exter-
nal opening to the bladder of Physophora tetras-
ticha. In Stephanomia it would not appear,
according to the description of Milne Edwards
(Ann. d. Sc. Nat. XVI. p. 218, PI. VIII. fig. 1. b.
2), that this organ had an external opening. Couch
( Froriep's neue Notizen, No. 273, p. 129) denies
that Physalia has the power to control the air of
its bladder. See also below, § 65.

2 Grant , Trans. Zool. Soc. London, 1. 1835, p. 9.;
Sars, Beskrivelser loc. cit. PI. VIII. fig. 18, e.*,
Milne Edwards , Ann. d. Sc. Nat. XVI. p. 201,
216, PI. IV. fig. 2, 3, PI. VI. fig. 1. c.5 and Will , loc.
cit. p. 9, 56, Taf. I. fig. 5.

In regard to the structure of these muscles,
Agassiz remarks : “ With all the power of the best
Oberhuuser Microscope, I have been unable to dis-
cover the slightest indication of striae on the mus-
cular cells ; nevertheless, it cannot be doubted
that they are voluntary muscles.” To this view I
may add my own of the same nature. — Fd.

$$ 59, GO,

THE ACALEPHAE.

63

CHAPTER III.

NERVOUS SYSTEM.

§59.

A nervous system has been found in many Acalephae. With the Cteno-
phora the oesophagus is surrounded by a ring formed of eight ganglia,®
and at the opposite extremity of the body there is a simple ganglion. Five
nervous filaments pass out from these ganglia, and along the sides of the
body are nervous fibres, which ultimately divide into delicate threads.®
The tentacles of Medusae are supplied with nervous filaments which issue
from a ganglion situated at their base.®

CHAPTER IV.

ORGANS OE SENSE.

§ 60.

With many Acalephae, there are, upon the borders and extremities of

1 These eight ganglia, which are connected
together by delicate cords, were first observed by
Grant (Trans. Zool. Soc. Lond. I. p. 10) in Cydip -
pe pileus. Compare, also, Wagner , Icon. zoot.
Tab. XXXIII. fig. 37, A. B. From each of these
ganglia two nerves pass off to the side, while a
third, traversing the interior of the body, and hav-
ing two or three swellings, is finally distributed to
the intestine. Patterson (The Edin. new Philos.
Join’. XX. p. 26), and Forbes (Ann. of Nat. Hist.
1839, p. 145), have also observed the oesophageal
ring in Cydippe , but did not perceive the ganglia.

2 Milne Edwards (Ann. des Sc. Nat. loc. cit.
I). 206, PI. IY. fig. 1) has observed at the poste-
rior extremity of the body of Lesueuria vitrea
(a new Bero'id) a ganglionic body which sends

* [ § 59, note 3.] The nervous system of the
Acalephae has been successfully studied by Agassiz
upon several genera ( Hippocrene , Tipropsis ,
Staurophora). His results are new, and different
from those of previous observers. I cannot do bet-
ter than to quote his words: “There is, unques-
tionably, a nervous system in Medusae, but this
nervous system does not form large central masses,
to which all the activity of the body is referred, or
from which it emanates. There is no regular com-
munication by#nervous threads between the centre
and periphery and all intervening parts *, and the
nervous substance does not consist of heterogene-
ous elements, of nervous globules and nervous
threads, presenting the various states of complica-
tion and combination, and the internal structural
differences, which we notice in the vertebrated ani-
mals, or even in the Mollusca and Articulata.”

out in front four filaments ; and upon the sides of
this animal a nervous cord, from which pass off
delicate branches at regular intervals. At the pos-
terior extremity of the body of Cydippe , Eucha-
ris and Medea , Will (Froriep's neue Notizen,
No. 599, 1843, p. 67, and Horse tergest. p. 44) has
likewise observed a round, yellowish ganglion, with
four prolongations, from which pass off twenty-five
or thirty nerves.

;i Ekrcnberg has found along the entire border
of the disc of Medusa aurita , and between each
two tactile filaments, a bifid nervous ganglion. He
affirms to have seen also two others similar, at the
base of each tentacle surrounding the genital organs.
See Abhandl. d. Berl. Akad. 1835, p. 203, Taf. IV.
fig. 1, x.-, and Muller'1 s Arch. 1834, p. 571.*

“ In Medusae the nervous system consists of a
simple cord, of a string of ovate cells, forming a
ring around the lower margin of the animal (PI. Y.
fig. 11, 2, 4, 5), extending from one eye-speck to
the other, following the circular chymiferous tube,
and also its vertical branches, round the upper
portion of which they form another circle. The
substance of this nervous system, however, is
throughout cellular, and strictly so, and the cells
are ovate. There is no appearance in any of its
parts of true fibres” (loc. cit. p. 232). That
this is the nervous system seems placed beyond all
controversy -, for, in a private letter, Agassiz has
informed me that in a new genus (. Rhacostoma ),
living on the shores of Massachusetts, he has seen
this system at night as an illuminated diagram. —
Ed.

THE ACALEPHAE.

64

$ 60.

their body, button and tongue-like organs, which, as they are connected
with neighboring ganglia, may well be regarded as organs of sense.

Their essential structure is a membranous capsule, containing a clear
liquid, in which are suspended crystalline corpuscles.

These organs, having sometimes a red pigment, have been taken for eyes ;
but, as most of them are without pigment, and- as the crystalline corpuscles
behave in acid like the Otolites of the higher animals, they have more
recently been better designated as organs of hearing.

The eight marginal, tongue-like bodies, found upon the disc of Medusa
aurita, have been regarded as eyes.® The sole fact for the support of this
opinion is the presence of pigment; for the small hexagonal crystals, irreg-
ularly scattered in the interior of these bodies, would scarcely allow them
to refract the light like a crystalline lens.

The Ctenophora have only a single organ of this nature, and which is
situated near the ganglion at the posterior end of the body. It has been
regarded both as an eye and as an organ of hearing.®

With many Discophora, these organs appear as pale-yellow, or even
colorless marginal corpuscles, having more or less calcareous bodies.®

It is yet doubtful whether the otolites of the Acalephae perform the same
movements as those of the acephalous and gasteropod mollusca.®

1 These marginal corpuscles, already observed in
the Medusae by Gaede (BeitrSLge zur Anat. u.
Phvs. der Medusen, 1816, p. 18, 28), and by Rosen-
thal (Zeitsch. f. Physiol. Bd. I. Hit. 2, 1825, p. 326),
were first described as eyes by Ehrenherg. See
Muller's Arch. 1831, p. 571, and Abhandl. d. Berl.
Akad. 1835, p. 190, Taf. IV. V.

2 Milne Edwards has called this body, in Lesu -

euria vitrea and Beroa Forskalii , “ Organe ocu-
liforme " (Ann. d. Sc. Nat. loc. cit. p. 206, 211,
PI. IV. 'fig. 1, k. and PI. V. fig. 4, i.). According
to Will (Froriep's neue Not. No. 599, p. 67, ami
Horse tergest. p. 45, Taf. I. fig. 2, 4, 20, b.), the red
pigment of these organs is entirely wanting in
Beroa , Eucharis and Cydippe , while the hexago-
nal calcareous corpuscles are very numerous — a
fact leading him to conclude that these organs are
auditory vesicles. •

3 According to Wagner (Ueber den Bau, &c.,
and Icon. zoot. Tab. XXXIII. fig. 31, g. 23, c. and
25), these corpuscles are pale-yellow in Pelagia
noctiluca , and colorless in Oceania , Cassiopea
and Aurelia. In Cephea, Will has observed only
pale-yellow corpuscles, filled with crystals. And,
according to him (loc. cit. p. 64, 68), the colorless
pedunculated marginal vesicles of Polyxenia leu -
costyla contain, each only a single round otolite,
while those of Cytaeis potystyla contain numbers,
colorless or yellow, and of irregular forms. He
has also observed (loc. cit. p. 72, Taf. II. fig 9,
10) that in Geryonia the number of these otolites
varies from one to nine. Milne Edwards (Ann.

* f § 560, note 4.] The organaof sense of the Aca-
lephae have been the objects of much study of late,
and to Agassiz we are indebted for the most minute
researches on these obscure points. He has shown
the eye-specks to be undoubted organs of sense,
from their connection with the nervous system.
With the naked-eyed Medusae, he regards them
light-perceiving instead of auditory organs. In
regard to the single organ found with the Cteno-
phora, and which Frey and Leuckart have re-

d. Sc. Nat. XVI. p. 196, PI. 1^ e.) has observed
upon the margin of the disc of Aequorea violacea
vesicles containing two or three spherical corpus-
cles, and which, probably, are auditory organs.
According to Sars ( Wiegmann's Arch. 1841, Th.
1. p. 14, fig. 60), and Will (loc. cit. p. 75, Taf. II.
fig. 21, A. B.), these marginal corpuscles are found
upon young Medusae belonging to Ephyra.

4 Will has never observed with the Otolites of
Acalephae similar movements to those of mollusca.
Kolliker (. Froriep's neue Not. No. 534, p. 82) has
observed vibratile cilia upon the inner surface of
the marginal corpuscles of Pelagia , Cassiopea ,
R/iizostomum and Oceania , which are pyriform,
and contain many calcareous crystals. In the
pedunculated vesicles of Geryonia , which contain
only a single crystal, these cilia are absent. In
none of the Medusae has he found collections of
pigment, and in Oceania (nov. spec.) only he has
observed a mass of brown pigment cells upon the
external and superior surface of the base of these
corpuscles 5 in the centre he perceived a round
transparent body, and upon the upper surface a
circular opening, so that the whole closely resem-
bles an eye, there being, moreover, a kind of pupil-
lary opening, and the traces of an optic nerve from
a ganglion.

According to the observations of Frey and
Leuckart (Beitr. &c. p. 39), the group of otolites
contained in the auditory organ of a Cydippe per-
form oscillatory movements, due evidently to vibra-
tile cilia situated on the auditive capsule.*

cently declared to be of an auditory nature, ho
remarks : “ I am inclined to consider this organ, or
this speck, as something similar to the central col-
ored speck which occurs in the middle of the disc
in Discoid Medusae, and which is particularly dis-
tinct in young animals soon after they have been
detached from the polyp-like stem on which they
grew, as a remnant of the connection which exists
between the mother-stem and its progeny in those
Medusae which multiply by alternate generations.”

$61.

THE ACALEPHAE.

65

Ur

CHAPTER V.

DIGESTIVE APPARATUS.

§61.

The digestive apparatus of the Acalephae is formed after several very
different types. The mouth is sometimes single and central, or there may
be many of them. It is often surrounded with arms and retractile filaments,
which are endowed with the prehensile and nettling organs just described.

The digestive cavity, which is always lined with ciliated epithelium, has
distinct walls, which are united immediately to the parenchyma of the
body, leaving, therefore, no surrounding cavity.

With those having a single mouth the stomach is of a variable size, and
has often caecal appendages. With Beroe,a) the mouth is very large and
free from tentacles, and opens into a very spacious stomach which occu-
pies nearly the whole body. But with Cestum, Cydippe and Lesueuria,
^he stomach is small, and appears like a cavity in the body and with
Cytaeis, Thaumantias and Geryonia, it is likewise small, and has the
shape of a tubular projection.®

That of Medusa has four saccular folds,® that of Pelagia ® six, and that
of Cyanea thirty-two.®

When the mouths are numerous, either, as in the Rhizostomidae,® there
are many canals which conduct the food through the arms upon which the
mouths are situated into the central stomach ; or, as in the Siphonophora,
each mouth opens into a particular tubular stomach. With these last,
however, a certain number of their tentacles are hollow, and have a mouth
at the extremity. As it has been observed that these suck in food and
digest it, their orifices have been regarded as mouths, and their cavities as
stomachs.®

1 Milne Edwards, Ann. d. Sc. Nat. XVI. pp. 5, 6.

v Esc/ischoltz , loc. cit. Taf. I. II. *, and Milne
Edwards, loc. cit. PI. III.

6 Will, loc. cit. Taf. II.

4 Baer , in MeckeVs deutschs. Ardh. VIII. 1823,
Taf IV. fig. 2 •, also, Ehrenberg in Abliandl. d.
Berl. Akad. 1835, Taf. III. fig. 1.

5 Wagner, Icon. zoot. Tab. XXXIII. fig. 5.

6 Gaede, loc. cit. Taf. II.

I Eysenhardt, Nov. Act. phystco-med. X. part
II. p. 391, Tab. XXXIV. fig. 1 ( Rhizostomum
Cuvieri).

8 This is so, for examples, in Diphyes (Will, loc.
cit. Taf. II. fig. 22) 5 in Physalia ( Offers Abhandl.
d. Berl. Akad. 1831, p. 162, Taf. I.) 5 in Stephano-
jnia (Milne Edwards, Ann. d. Sc. Nat. XVI. PI.
VII. IX. X.) 5 and in Physophora (Philippi,
Muller's Arch. 1843, Taf. V. fig. 1, 4).

(Loc. cit. p. 316.) On a preceding page he says :
“ That this may be the case seems probable when
we consider the relation of the two sorts of appa-
ratus in the two types. The upper nervous ring in
Sarsia bears the same relation to the central ali-
mentary cavity, and to the pigmented disc, that the
ganglion and eye-speck of Beroe bear to the chy-
6*

Philippi , however, affirms that in this last
genus these canals are organs of absorption, and that
the true stomach, which has a simple mouth, is
concealed at the base of the tentacles (loc. cit. p.
63, Taf. V. fig. 10).

I think, however, that this opening belongs to the
respiratory system, as also does a similar opening
in Vclella and Porpita, which Lesson (Voyage de
Duperrey, loc. cit. p. 49, 56, No. 6, fig. B. 5 and No.
7, fig. C. C.) has regarded as a mouth.

The tubular tentacles of these animals are noth-
ing but stomachs 5 and Lesson himself has called
them upoches stomacales,” since they digest
food. It would, moreover, be strange that these
organs, which, in Physalia, have been admitted to
be stomachs, should perform another function in
Physophora, Velella, and Porpita, where their
structure is the same. But further researches are

miferous system, which opens above its gelatinous
disc, notwithstanding these openings.” (p. 248.)
This point, fully as interesting from its zoological
importance as from its morphological relations,
can be settled only by a knowledge of the embryol-
ogy of these animals. — Ed.

66

THE ACALEPHAE.

§ 62.

The Acalephae have no true digestive tube. But, as such, has been
regarded a system of vascular cauals filled with water, and which, de-
parting from the stomach, traverse the whole body. But these, although
sometimes seen to contain faeces, seem to belong more properly to the
respiratory system.®

In none of the Acalephae has there been found anything like an hepatic
organ. (10)

CHAPTER VI.

CIRCULATORY SYSTEM.

§ 62.

Until lately, the longitudinal and circular canals which, in some Acale-
phae, are spread out through the entire body, have been regarded as
belonging to a vascular, sanguineous system. But more recently these
have properly been considered as aquatic-respiratory organs, there having-
been found, moreover, other vessels of exceedingly thin walls, and of a
sanguineous nature.

These last constantly accompany and surround in a tubular manner the
aquiferous canals ; and it is quite rare that small branches are distributed
to the general parenchyma.

The delicate walls of these vessels have neither longitudinal nor circular
fibres, neither are they lined with ciliated epithelium. They circulate a

required to thoroughly settle this point. See below,
the respiratory organs. See also Hollar d, who
unhesitatingly regards the canals, which, with Ve-
le.Ua , communicate externally by a central opening,
as a digestive cavity, and thinks he has observed
in their walls brownish spots representing the
hepatic cells ; see Ann. d. Sc. Nat. III. 1845,
p. 249, PI. IV. bis.

9 The aquiferous canals of the respiratory sys-
tem having been regarded as intestinal tubes, their
orifices, which in the Ctenophora are situated at
the extremity of the body, and in the Discophora
upon the borders, have been considered as anal
openings 5 and especially so, since in these two
orders, accidental faeces in these canals are expelled
through these orifices. See Will , loc. cit. p. 28,

* [§ 61, note 9.] Upon the nutritive system of
the Acalephae, see Forbes (loc. cit. p. 4), but
especially Agassiz (loc. cit.), who has studied the
subject with conscientious care. There is no dis-
tinction between the alimentary canal proper and
the vascular system, for the one opens by large
tubes into the other. The Acalephs, therefore, cir-
culate chyme , and here we have the rudest form
of circulation. If this idea is once well considered,
the relations of their nutritive apparatus in general
will be quickly appreciated.

The variations in the shape and form of the di-
gestive apparatus are wide and numerous, 'but

and Ehrcnberg , Abhandl. d. Berl. Akad. 1835, p.
189, Taf. I. IV. fig. 2, z*

19 Acalephm possess an extraordinary digestive
power, which is the more singular as no secretory
organ has been found on the sides of their stomach.
Mertens (MYm. d. l’Acad. de St. Petersburg, loc.
cit. p. 490, Taf. I. fig. 5, 6, a. ; and p. 518, Taf.

VIII. fig. 4, Taf. IX. fig. 1, f.), however, affirms to
have seen in Cestum and Cydippe four vessels in
this situation, which are perhaps hepatic organs.
The orange-colored cords found upon the sides of
the stomach of Stephanomia, and which Milne
Edwards (Ann. d. Sc. Nat. XVI. p. 222, PI. VII.

IX. X.) has taken for genital organs — may they
not also be hepatic organs ? f

their importance is rather in Zoology. See Agas-
siz for the details of Sarsia , Hippocrene , Tiarop-
sis , Staurophora , Pleurobranchia , Bolina. —
Ed.

f [§ 61, note 10.] Kblliker (Siebold and Kolli-
ker^s Zeitsch. IV. lift. 3, 4, p. 313) has observed with
Velella and Porpita a glandular mass, correspond-
ing most probably to a liver. It had before been
regarded as such by Belle Chiaje , but Kblliker
has given it a special description. It consists of a
brown mass which communicates with the bottom
of the stomachal cavity by branched, anastomosing
ducts. — Ed.

§63.

THE ACALEPHAE.

67

colored fluid and colored corpuscles ; and these corpuscles are not found
except in those vessels surrounding the aquiferous canals.

There is no regular circulation, but the shifting motion of the blood
hither and thither is due to irregular contractions of various parts of the
bod_y.(1)

CHAPTER VII.

RESPIRATORY SYSTEM.

§ 63.

The entire body of the Acalephae is traversed by canals which receive
water from the stomach, or directly from without, and which is ejected
through openings upon the extremity of the body and on the margin of the
disc.

These aquiferous canals are lined with a delicate, ciliated epithelium, by
means of which accidental particles of food or faeces are quickly removed.
They have been regarded both as digestive and as sanguineous organs.
But that they are respiratory organs is highly probable, not only from their
structure, — the cilia producing a constant renewal of water, — but also from
the fact that they are surrounded by real sanguineous vessels.

This aqueous circulation is oscillatory from one side of the body to the
other, being interrupted only by those contractions of the body which occur
when fresh water passes from the stomach into the canals. a)

1 These new details upon the sanguineous system
of the Acalephae are due to Will (Horae tergesfc.
p. 34, and Froriep's neue Not. No. 599, 1843, p.
66). In Beroe , he has been able to clearly distin-
guish the sides of these vessels from those of the
aquiferous canals contained in their interior, for
the first are covered with numerous red pigment
cells.

The blood of this animal has a greenish hue, and
contains spherical or slightly elongated red corpus-
cles, with large nuclei. But, besiue these, Will has
found in Cydippe other nucleated cells of a green-
ish color. In Polyxenia , there is no sanguineous
system separate from the aquiferous canals, which,
in Cytaeis and Geryouia are quite surrounded by
them. The vessels of Cephea contain brown cor-
puscles •, and Will has concluded that the reddish
threads found along the aquiferous canals of this
animal, and which Ehreriberg (Abhandl. d. Berl.
Akad. 1835, p. 195, Taf. VI. fig. 3, and Muller's
Arch. 1834, p. 568) has taken for striated muscles,
are really blood-vessels. Profound researches must
decide the real relations of the aquiferous canals to
the sanguineous system filled with a violet liquid
of Velelta , as described by Costa (Ann. d. Sc.
Nat. XVI. p. 188, PI. XIII. fig. 3). It should be
mentioned that the blood-system of the Acalephae,

* [§ 62, note 1.] A true circulatory system has
not been observed also by Dana (Struct, and
Class, of Zoophytes, 1846, p. 12), by Forbes (Brit.
Naked-eyed Medusae, I84S, p. 6), by Agassiz
(Contributions to the Nat. Hist, of the Acalephae
of North America, Mem. Amer. Acad. Boston,
1850, p. 260), and by Busch (Beobacht. ub. Anat.

which Will has described with so much positive-
ness, is not verified either by Bcrgmann or Frey
and Leuckart (Beitr. p. 38), after numerous spe-
cial researches.*

1 If, and especially with the Discophora, these
canals have been taken for digestive tubes, it is
because faices and particles of food have been here
found, and which have been ejected through the
openings on the borders of the body. But the real
function of these openings is to discharge the water
unfit for respiration 5 and it is only during the in-
gestion of this liquid that these foreign particles are
thus introduced. This communication between the
respiratory and digestive systems reminds one of
the Polyps, where (as in the Anthozoa) the open-
ings in the stomach allow its contents to pass into
the cavity of the body, which last may be likened
to the aquiferous system. On the other hand, the
opinion that these canals are blood-vessels would
be supported by the Ctenophora, since here they
are filled with a red liquid 5 but, according to Will
(Horae tergest. p. 34), this liquid is not in these
canals, but in proper blood-vessels surrouuding
them. He denies, also, that these blood-vessels of
the Ctenophora open upon the surface of the
body, or that the blood escapes outward mixed
with faeces.

u. Entwick. einiger wirbellosen Seethiere, 1851, p.
13). It may, therefore, be concluded that these
animals have no system of this kind, and especially
so a3 Agassiz failed to notice it after the most inti-
mate research upon the Berdid Medusae (loc. cit.
p. 313), which were the objects of Will's study.
— Ed.

68

THE' ACALEPHAE.

$64.

§ 64.

With the Ctenophora, this respiratory system consists of an infundibuli-
forrn cavity, communicating with the stomach by two orifices, situated at its
base and surrounded by sphincters.

Numerous aquiferous canals pass out of this cavity, traverse the body in
a longitudinal direction, and finally anastomose with an annular vessel
surrounding the mouth ; but, beside these, there are two short canals which
pass directly to the posterior extremity of the body, where they open
externally.

With Eucharis and Cydippe, these canals are differently distributed ;
thus, two go to the tentacles, two to the sides of the stomach, and four to
the sides of the body. The same is true with Beroe, excepting that those
to the tentacles are wanting. The lateral canals divide, at a short distance
from the cavity, into as many branches as there are sides. With Cydippe ,
the excretory canals are simple ; with Eucharis they are provided with
vibratile lamellae, and with Beroe with branching appendages. <1)

With the Discophora, numerous aquiferous canals pass from the stomach
or its appendages, traverse the disc in a radiating manner, sometimes bifur-
cating, and terminate at the borders of the disc in an annular vessel which
opens externally by numerous orifices.

In Cytaeis, Geryonia and Thaumantias, there are four of these canals,
arranged in a crucial manner ;1 (2) and in Aequorea there are seventy-four
disposed in a ray-like way. (3) 4 5

In Medusa aurita, there pass from the four folds of the stomach six-
teen of these canals, eight of which are simple, and eight bifurcating
numerously before reaching the marginal vessel of the disc.<4) With Sthe-
nonia and Aurelia (5) they are very numerous and widely branched.

With Medusa aurita , the terminal openings of the annular vessel are
eight, and regularly alternate with the organs of hearing there situated.®
But in Cephea these openings are said to be directly beneath these last-
named organs.®

With the Siphonophora, an aqueous system has not yet been well made
out. There is, however, with some, an elongated cavity which is perhaps
respiratory, and which, in some species, opens into the stomach, and in others
directly upon the outer surface.®

1 Will (Horse tergest. p. 30, Taf. I.) has made
very minute researches upon the aquiferous sys-
tem of Eucharis , Cydippe and Beroe. That of
Beroe ovatus , Forskalii , and of Lesueuria vi-
trea , has been carefully described and figured by
Milne Edwards as a circulatory system (Ann.
d. Sc. Nat. XII I. p. 320 $ XVI. p. 203, 213, PI.

ni.-vi.).

2 Will , loo. cit. Taf. n. fig. 5, 7, 8, 14, 16.

8 Milne Edwards , Ann. d. Sc. Nat. XVI. p.

197, PI. 1. fig. 1.

4 Rosenthal , Zeitsch. f. Physiol. I. Hft. 2, Taf.

XI. ; also, Ehrenberg , Abhandl. d. Berl. Akad.

1835, Taf. I. bis. HI.

5 Eschscholtz , loc. cit. Taf. IV. 5 also Brandt ,

M6m. de l’Acad. d. Sc. de St. Petersburg, IV. 1838,

PI. IX. X. XI.

0 Ehrenberg , Muller's Arch. 1834, p. 566 5
also, Abhandl. &c. loc. cit. p. 188, Taf. I. fig. 1,
w. and Taf. IV. fig. 2, z.

7 Will , loc. cit. p. 60.

8 In Diphyes , this canal terminates in this way
by an oval dilatation, lined with ciliated epithelium,
and has perhaps properly been regarded by Will
(loc. cit. p. 78, Taf. II. fig. 22, a.) as a respiratory
organ. A similar cavity, with a ccecal appendage,
is found in Ersaea (Will, loc. cit. p. 81, Taf. II.
fig. 27-31, d. e.). If the arms provided with open-
ings, of the Physophorae, are really stomachs, then
the cavity beneath them, which has a canal
passing along the axis of the animal, should be
taken as belonging to the aquiferous system, for it
receives water by an opening at the base of the
anus. This same opening has been taken for a
mouth by Philippi (Muller's Arch. 1843, p. 63,
Taf. V. fig. 10). According to Lesson (Duper-
rey , Voyage, loc. cit. No. 6, fig. B.), there is be-
tween the suckers of Velella an orifice which leads
from before backward into a large branching canal.
This structure, hitherto regarded as a digestive

§§ 65, 66.

THE ACALEPHAE.

69

CHAPTER Y III.

ORGANS OF SECRETION.

§ 65.

The air-cavity of certain Siphonophora, which is surrounded by a dou-
ble membrane, ought probably to be regarded as an organ of secretion ; for,
according to many naturalists, the air contained could not have been de-
rived from without, and consequently was secreted by the sides of the
internal membrane. (1)

CHAPTER IX.

ORGANS OF GENERATION.

§66.

Reproduction by fissuration and gemmation with the Acalephae has
been observed only in the youngest states of certain Medusae. a> But repro-

cavity, belongs probably to the aquiferous system.
That which in Porpita has been taken for a mouth,
belongs probably, also, to the same system. I
would not, however, deny that another significa-
tion may be given to the so-called respiratory and
digestive organs of the Siphonophora.

If one prefers, with Philippi , to regard the open-
ing between the tentacles of Physophora , Velella
and Porpita , as a mouth, then the cavity of these
tentacles should belong to the aquiferous system.
Moreover, these tentacles, as to their form and mo-
bility, remind one of the pedicles of the Echino-
dernis *, but it is remarkable that they can absorb
food.

Sars (Faun, littoral. Norveg. p. 34, 42, Tab. VI.
fig. 3, gg. and Tab. VII. fig. 3, e.) has observed in
the interior of the cartilaginous, natatory pieces of
the Physophoridae and Diphyidae, aquiferous
canals which are probably of a respiratory nature.

Hollard , likewise, regards the hollow and tubuli-
form tentacles of Velella as aquiferous tubes, and
in this way, as the tentacular feet of the Echino-
derms, includes them in the aquiferous system. See
Ann. d. Sc. Nat. III. 1845, p. 250.

1 Many naturalists entirely deny the presence of
openings in these aerial cavities, and do not admit
that they are filled with gas. Thus Philippi
( Muller's Arch. 1843, p. 63) affirms to have found
neither external opening nor air in the pouch at
the end of the longitudinal canal of Physophora
tetrasticha. Olfers (Abhandl. d. Berl. Akad.
1831, p. 165) has not been able to find in Physalia
the opening of the internal sac, said to be near the
one of the external sac. In fact, Bennett (Proc.
Zool. Soc. London, 1837, p. 43 ; and Wiegmann's
Arch. 1838, II. p. 332), with the same species,

* [ § 66, note 1.] See also Huxley (Ann. Nat.
Hist. VI. p. 394), who has described the reproduc-
tive processes of the Diphyidae, and shown that

has not seen an opening of this cavity, and was
unable to force air from it. Future researches
must determine if these pouches have not a respir-
atory function.

1 See, upon this subject, the Embryology of these
annuals, below. It is not yet demonstrated that
adult Acalephae reproduce by fissuration ; and
although Mertens (M6m. d. l’Acad. de St. Peters-
burg, II. p. 494, PI. I. fig. 2-4, and p. 527) has
observed detached corpuscles from the body of
Cestum and Cydippe swim freely about, and rap-
idly enlarge, yet his observations are here lim-
ited.

In the same way, Will (Hone tergest. p. 42) has
seen analogous bodies detached from Eucharisy
and has found in the water others supposed to be-
long to the Ctenophora, but has not traced their
further condition.

Propagation by buds has also been found with
the Acalephs, through the excellent researches of
Sars (Fauna littoral. Norveg. p. 11, Tab. IV. fig.
8-12), for this observer has seen on the external
surface of the tubuliform stomach of Cytaeis octo -
punctata , and upon the four ovaries of Thauman-
tias multic errata, small campanuliform Acalephs
resembling their parent, in the process of develop-
ment, and which were finally detached. In the
genus Agalmopsis which is allied to Agalma ,
Sars has observed (Ibid. p. 38, Tab. VI. fig. 14-17)
campanuliform bodies sprout out between the pre-
hensile filaments and the tubuliform stomach, and
which were finally detached, swimming freely like
the Discophora. According to Sars , also (Ibid,
p. 43, Tab. VH. fig. 11, b. 13, b, and 14), there is,
likewise, an analogous mode of propagation with
Diphyes .*

they multiply by gemmation as well as by ova.
See, also, Muller's Arch. 1851, p. 380, Taf. XVII.
— Ed.

THE ACALEPHAE.

70

§§ 67, 68.

duction by eggs, and consequently by the means of proper genital organs,
has been observed in all the families.

With the Ctenophora,(2) both sexes are combined in the same individual;
but with the Discophora, the individuals are of Oi- sex alone.®

§ 67.

The eggs are spherical, _ 1 '"'-rounded by an exceedingly thin envelope.
The vitellus is of a whitish violet or yellow color, and contains a germina-
tive vesicle, and germinative dot.®

The spermatic particles, which have generally the form of Cercaria (that
is, a head and a filiform tail), are very active, and sulfer no change in water.®

In some Siphonophora, they appear to have a linear form, and attain a
very great size.®

§68.

The genital organs are not developed except at the epoch of procrea-
tion, and this period is very brief. On this account, their existence has
often l 'j escaped the notice of observers.

The male and female organs so closely resemble each other, as to color,
form and position, that they are easily confounded. They consist either of
elongated pouches, or of riband-like bands, which are situated in different
parts of the body. In the first case, the sperm and eggs escape through
particular excretory canals ; in the second, they escape directly outwards
from the ovaries or testicles, or pass first through large cavities which com-
municate externally.

As they have no copulatory organs, the water is the medium of fecunda-
tion. In this way the unaffected spermatic particles are brought in direct
contact with the eggs.

2 Willy Froriep's neue Not. No. 599, p. 66.

3 Siebold, Froriep's neue Not. No. 1081, 1836,
p. 33 *

1 Wagner (Prodrom. loc. cit. Taf. I. fig. 2 ; and
Icon. zoot. Tab. XXXIII. fig. 15-17) and Siebold
(Beitrage z. Naturgesch. wirbelloser Thiere. loc.
cit. Taf. I. fig. A. B.) have figured the eggs of Cy-
anea pelagia, and of a Medusa.

2 The spermatic particles of Eucharis and Be-
roe consist of a round body, having a delicate and
very movable tail ( Willy loc. cit. Taf. I. fig. 6, 24).
In Cydippe they are similar ( Krohriy Froriep's
neue Not. No. 356, 1841, p. 52). This is likewise
true of those of the Discophora ; see Siebold,
Beitrage loc. cit. Taf. I. fig. c. ( Medusa ) ■, Kblli-
ker y Beitrage loc. cit. Taf. I. fig. 8, 9, 10 ; and
Milne Edwards , Ann. d. Sc. Nat. XVI. PI. I. fig.
1, d. ( Rhizostomurriy Chrysaora and Aequorea ) j

Wagner , Icon. zoot. Tab. XXXIII. fig. 20, and
Willy Horae tergest. Tab. II. fig. 12 ( Pelagia and
Geryonia ).

•• the spermatic particles of the Discophora,
see rr (tliiker in the Neue schweiz. Denkschr.

VIII. p. Taf. II. fig. 18 ( Cassiopeia ). f

3 It may be that the stout linear and active
bodies, seen by Will (loc. cit. p. 78, 81, Taf. II. fig.
26) in the respiratory cavity, the stomach and the
general cavity of the body of Diphyes and Ersaeay
and which he was inclined to regard as Entozo i
are the spermatic particles of these animals, since
they quite resemble those of Alcyonella and Cris-
tatella.

According to Sars (Faun, littor. &c. p. 38), the
spermatic particles of Agalmopsis have a cerca-
ria-form. \

* [ § 66, note 3.] Reproduction by fissuration
has been observed with the Discophora by Kblli
ker ( Siebold and Kdlliker's Zeitsch. IV. p. 325) 5
he witnessed this phenomena with Stomobrachium
mirabile. It does not appear, however, that he
has observed this process with adult forms 5 for he
remarks that there is reason to believe that this
Stomobrachium is only a young, imperfect form
of his Mesonema coerulescens. — Ed.

t [§ 67, note 2.] The spermatic particles of the
Acalephae have invariably, I think, a cercaria-

form, like those of the Polyps, and like which, also,
they are developed in special daughter-cells. — Ed.

} [§ 67, note 3.] These bodies mentioned by
Will as spermatic particles have since been exam-
ined by Huxley (loc. cit.), who thinks they are not
of this nature, a view which is otherwise probable
from the fact that he found no male generative sacs,
and also because, as I have shown (see my note
after § 46, note 5), these particles with Alcyonella
have a cercaria-form. — Ed.

THE ACALEPHAE.

71

$ 69.

§69.

The position of the sexual organs varies in the different orders, in the
following manner :

1. With the Ctenophora, which are hermaphrodites, they are situated
along the sides, under the form of elongated utricles, the testicles being
on one side and the ovaries on the other. They have a nodulated appear-
ance, and from the lower part of each passes off an excretory duct, which
runs toward the mouth, but the terminal opening of which has not yet been
well made out.®

2. With many Discophora, these organs are arranged like rays, passing
from the centre to the border of the disc. In Oceania , Cytaeis, Geryonia
and Thaumantias , the four saccular ovaries or testicles form at the centre
of the disc a cross, which is traversed by four aquiferous canals.® Their
excretory ducts pass towards the base of the stomach, but their terminal
openings are not distinct.® In the disc of Aequoreaviolacea, seventy-four
ray-like bands are spread out, and the free plicated borders of these hang
beneath the inferior surface of the disc, thus permitting the free escape of
the eggs and sperm into the water.®

8. Another group of the Discophora have at the base of their tentacles
four large openings, which lead into as many cavities in the disc.® At the
base of these cavities, which formerly were regarded as respiratory organs,
the genital organs are situated in the form of plicated bands. These as four
bands (testicles or ovaries) are bent either into an angle or the arc of a cir-
cle, forming sometimes a star with four rays,® and sometimes a four-1 obed
rosette.® If these cavities increase in number, the genital organs increase
in the same proportion.® The border of these organs is generally pro-
vided with numerous tentacles which project into the cavity.® In the riband-
like testicles numerous small sacs are observed ; each one ef these opens
separately into the genital cavity, while the eggs, on the contrary, are sep-
arated from the similarly-formed ovary only by a gradual constriction of
the latter. (1C) __

4. With the jiphonophora, all the relations of these genital organs still
require much investigation. With the Diphyidae, they consist of sacs
communicat: ,g with the general cavity of the body.<u> During the epoch

1 Will , Horae tergest. p. 38, Taf. I. fig. 22, 23.

2 Wagner, leones, zoot. Tab. XXXIII. fig. 26,
a. a. *, Will , loc. cit. Taf. II. fig. 5, 7, 8, 14, 16 ;
Bfainville, Manuel d’Actinol. 182. A'VXVTI.
fig. 3 : and Sars, Beskrivelser loc. cit. jri. » .

12, 13. „

3 Will, loc. cit. p. 71.

4 Milne Edwards , Ann. d. Sc. Nat. XVI. p. 198,
PI. I. fig. 1, a. b.

5 Gaede , Beitriige loc. cit. Taf. I. fig. 1, c. ( Me-
dusa) ■, and Lesson in Duperrey, Voyage loc. cit.
No. 12, 13 ( Chrysaora ).

0 Rhizostomum.

1 Chrysaora, Medusa , Pelagia and Aurelia.

See Ehrenberg , Abhandl. d. Berl. Akad. 1835,
Taf. I. fig. 1 ; Wagner , Icon. /not. Tab. XXX III.
fig. 1 •, and Brandt , M6m. de l’Acad. de St. Peters-
burg, IV. PI. IX. X. With the male and the female
Cephea , I have found the testicles and the ovaries
disposed exactly as with the 1 1 2 3 4 5 6

6 In Cassiopea, these organs au. in number.
9 Medusa and Pelagia ; see Ehrenberg , loc.

cit. Taf. VII. ; and Wagner , Icon. zoot. Tab.
XXXIII. fig. 13.

19 Siebold , Beitrage loc. cit. Taf. I. fig. 20, 23 ;
and Kb! Ulcer, Beitrage loc. cit. p. 40.

li In Diphyes and Ersaea, a sac filled with cells
opens into the general cavity of the body, and
communicates beside with the stomachs and respi-
ratory cavities. Will (Ilorae tergest. p. 78, 81.
Taf. II. fig. 23, c.) regards this sac as a sexual
organ ; and Me yen (Nov. Act. physico-med. XVI.
Suppl. 1, 1834, p. 214, Tab. XXXVI. fig. 2, h. and
fig. 6, 7) asserts to have seen eggs in it. Accord-
ing to Philippi ( Muller's Arch. 1843, p. 63, Taf.
V. fig. 10, a. b.), the grape-like clustered genital
organs, with Physophora, are situated between the
prehensile organs 5 the smallest containing in each
lobule six to ten eggs, and the largest a granular
liquid (Sperm ?).

Holland (Ann. d. Sc. Nat. III. ~ or’ PI.
IV. bis. fig. 33, 34) has found bolij . .. .;> of

ovaries ni 1. ' ■ ^ the tubuliform tentacles

(stomachs,. M v. „ ... p. 37, PI. V.) has also

72

THE ACALEPHAE,

§ 70.

of procreation, the females of some Discophora are easily distinguished
from the males by the numerous pouches of their tentacles, and in which
eggs and newly -hatched young are carried for a short time.*121

§70.

As yet, the development of a few only of the Acalephae has been traced.
It is attended by a remarkable metamorphosis.

After the usual segmentation of the vitellus, ovoid embryos resembling
infusoria are developed ; these turn freely on their axis, and swim about in
the water by means of ciliated epithelium. (1) Shortly after, they become
attached by the anterior extremity to some object. Upon the opposite free
extremity tentacles appear, and between them the mouth. The animal has
then the form of a Polyp. (2) It is during this period that the young ani-
mal reproduces by gemmation ,(3) and sometimes by transverse fissuration.
This last mode occurs in the following remarkable manner :

The polyp-like animal increases in length, and its body divides trans-
versely into many segments. Around each of these segments eight bifid
processes are developed ; after this, each segment is successively separated
from before to behind, and they float about for a time as eight-rayed Aca-
lephae, but soon attain, however, their adult condition. <4J

seen genital organs of the same form between the
tentacles of Agalmopsis ; but he found at the same
time (loc. cit. p. 38, 43), in the campanuliform individ-
uals produced from buds, testicles with Agalmopsis ,
and ovaries with Diphyes. It may therefore be
justly supposed that these various Siphonophora
are compound, sexless individuals, which, like the
Hydrina and Sertularina, reproduce by alternation
of generation, — that is, by buds, — individuals
having sex.

1 '2 Medusa aurita and Cyanea capillata ; see
Ehrenberg, Abhanal. &c. loc. cit. Taf. III. fig. 1,
2, Taf. VIII. fig. 1 *, also, Sars in Wiegmann's
Arch. 1841, I. p. 19.

1 The development and metamorphosis of Me-
dusa aurita and of Cyanea capillata have been
observed by Siebold (BeitrSge loc. cit. p. 21, Taf.
I. II. *, and Froriep's neue Not. No. 166, 1838, p.
177) ; and by Sars ( Wiegmann’s Arch. 1841, 1. p.
19, Taft I.-IV.). In the first stage of development
(see Ehrenberg , Abhandl. &c. loc. cit. Taf. VIII.
fig. 15-18 5 also, Siebold , Beitrage loc. cit. Taf. I.
fig. 17-19 ; and Sars , Wiegmann's Arch. loc. cit.
Taf. I. fig. 1-6), these infusoria-like Medusae have
been regarded by Baer as the larvas (MeckeVs
Deutsches Arch. VIII. 1823, p. 389).

2 Siebold, Beitrage loc. cit. p. 29, Taf. I. fig.
25^-33, Taf. II. fig. 34 ; and Sars , Wiegmann’s
Arch. loc. cit. Taf. I. fig. 7-31. During my last
visit at Trieste (autumn of 1847), I convinced
myself that the young of Cephea Wagneri are
developed wholly like those of Medusae, by passing
from infusoria-like forms to polypoid young ani-
mals.*

8 The reproduction of the polyp-form Medusae
by buds has been observed by Sars in Cyanea

* [ § 70, note 2.] See, also, for recent researches
on the development of Cephea, Ecker, Bericht iib.
die Verhandl. d. naturf. Gesellsch. in Basel. VIII.
1849, p. 51 *, Busch , Beobachtungen iib. die Anat.
&c. Berlin, 1851, p. 30 ; and Frantzius , in Sie-

capillata. He has also seen them develop pedi-
cles from the end of which new individuals would
appear, which resembled Polyps. See Wiegmann’s
Arch. loc. cit. p. 26, Taf. I. fig. 37, 41, 42, 38, 39, 40.

4 These young Medusae, whilst composed of rings,
have been taken for a new genus (Scyphistoma) of
Polyps by Sars (Isis. 1833, p. 222, Taf. X. fig. 2).
Steenstrup (Ueber d. Generationswechsel, p. 17)
has regarded them as nurses of the Medusae. At
a latter period, when the rings have been separated
and have acquired the bifid prolongations, Sars
(Isis. 1833, p. 224, Taf. X. fig. 4 ; and Beskrivel-
ser, &c., p. 16, PI. III.) has described them as a
new species of Medusae (Strobila octoradiata).
But lately he has perceived that they are the young
of Medusa aurita ( Wiegmanri's Arch. 1837, I.
p. 406) ; it did not occur to him, however, that these
young constitute, very probably, the genus Ephyra
of Eschscholtz (see Wiegmann’s Arch. 1841, Th.
I. p. 10). It will probably be discovered that
many small campanulate or discoid Medusae
are only the young of other Acalephae ; for it is very
likely that they all undergo a similar metamorpho-
sis. It may also prove that many naked Polyps
are only transitionary forms of known species of
Acalephae. In this connection the observation of
Dujardin (Comp. rend. 1843, p. 1132) deserves
the attention of naturalists. In tracing the devel-
opment of one of the Discophora allied to Oceania ,
he observed that this animal in its early condition
separated from a corallum resembling that of Syn-
coryne, and was of a form quite like an Eleuthe-
ria. However various these developing forms may
be, that one must be regarded as the real one
wliich exists during the development of the testi-
cles and ovaries. t

bold and Kblliker's Zeitsch. f. Zool. IV. p. 118,
June, 1852. — Ed.

f [ § 70, note 4.] In regard to the development
of the Acalephae, it may be mentioned that recent
researches, few as they are, have verified some

§70. THE ACALEPHAE. 73

of the hypotheses suggested in the above note.
Hitherto there has been much confusion on this
subject, from the want of complete series of obser-
vations ; even now the whole class can be regarded
only in a somewhat transitionary state, in a zoological
point of view. Many genera which have hitherto
been regarded good and permanent will no doubt,
as Siebold has remarked, prove to be only unde-
veloped forms of well-known species. As already
stated, Agassiz regards the Hydroid Polypi as true
Acalephae, and the analogy which exists between

7

the embryos of Medusae and Polypi may be the
foundation of many other important changes. At
present, however, broad generalizations must be
deferred until we have extensive and serial re-
searches in the embryology of these animals. For
separate details on the development of some forms,
see Busch , loc. cit. ( Sarsia , Lizzia , Cephea , Eu -
doxia , Diphyes ) Huxley , loc. cit. (Diphyidae,
Physophoridae) ; Agassiz and Desor , loc. cit.
(Medusidae). — Ed .

BOOK FOURTH.

ECHINODEBMATA.

CLASSIFICATION.

§71.

The Echinoderms have a more or less coriaceous envelope, filled with cal-
careous, reticulated corpuscles. These last are sometimes so numerous that
they form a real shell, composed of plates, movable, or tightly bound
together. In the ray-like, symmetrically-arranged systems of organs, the
quinquenary number prevails.

In many species the digestive canal is asymmetrical. All are marine,
and most of them move by means of particular, erectile suckers. Others
progress by vermiform motions, and some swim freely by moving their rays
like oars. Only a few are stationary. All are without copulatory organs.

ORDER I. CRINOIDEA.

The calcareous shell, composed of movable pieces, forms a true cutane-
ous skeleton. The body is ray-like ; the digestive canal, asymmetrical.

Family : Encrinidae.

Genus: Pentacrinus.

Family : Comatulinae.

Genus : Comatula.

ORDER II. AST ERO IDEA.

The calcareous shell, composed of movable pieces, forms an internal skel-
eton. The cutaneous covering is sometimes coriaceous, and sometimes cal-
careous. The body is ray-like, and the digestive canal symmetrical.

Family : Ophiuridae.

Genera : Astrophyton, Ophionyx, Ophiothrix, Ophiomastix, Ophiocoma,
Opkiolepis, Ophioderma.

§71.

THE ECHINODERMATA.

75

Family : Asteroidae.

Genera: Luidia , Astropecten, Ctenodiscus, Archaster, Stellaster, Astro go-
nium, Oreaster, Pteraster, Asteriscus, Culcita, Ophidiaster, Chaetaster ,
Solaster, Eckinaster, Asteracanthion.

ORDER III ECHINOIDEA.

The calcareous shell forms a spherical or discoid shield, composed of im-
movable plates. The digestive canal is asymmetrical.

Family : Echinidae.

Genera : Echinus, Cidaris.

Family : Clypeastridae.

Genera : Laganum, Scutella, Encope, Rotula, Lobopkora, Echinocyamns,
Mellita, Echinanthus.

Family : Spatangidae.

Genus : Spatangus.

ORDER IV. HOLO THURIOIDEA.

In place of a calcareous shell, the cutaneous envelope contains a greater
or less number of calcareous reticulated corpuscles. The oesophagus is
surrounded by a calcareous ring, constituting the rudiment of an internal
skeleton. The body is cylindrical. The digestive canal, generally asym-
metrical.

Family : Holothtirinae.

Genera : Holothuria, Pentacta, Bohadschia, Cladolabes.

Family: Synaptinae.

Genera : Synapta, Chirodota.

ORDER V. SIP UNC ULOIDEA.

The cutaneous envelope is coriaceous, and free from calcareous corpus-
cles. There is no calcareous ring about the oesophagus. The body is
cylindrical ; the digestive canal, usually asymmetrical.

Family : Sipunculidae.

Genera : Sipunculus , Phascolosoma,

Family : Eciiiuridae.

Genera : Thdlassema, Echiurus.

76

THE ECHINODERMATA.

§ 72.

BIBLIOGRAPHY.

Tiedemann. Anatomie der Rohrenholothurie, des pomeranzenfarbigen
Seesterns und Steinseeigels. Landshut, 1816.

Sharpey. Cyclop, of Anat. and Physiol. Art. Echinodermata, vol. II.
p. 30. London, 1839.

Agassiz. Monographies d’Eckinodermes vivans et fossiles. Neuchatel,
1838, 1-3% Livr.

Valentin. L’Anat. du Genre Echinus. Neuchatel, 1842. 4e Livr. des
Monographies d’Echinodermes.

Forbes. A History of the British Star-fishes, and other animals of the
class Echinodermata. London, 1841.

Muller und Troschel. System der Asteriden. Braunschweig, 1842.

ADDITIONAL BIBLIOGRAPHY.

Muller. Ueber die Larven und die Metamorphose der Ophiuren. In
the Transact. Berlin Acad. 1846.

Ueber die Larven und die Metamorphose der Echinodermen. Ibid. 1848.

Ueber die Larven und die Metamorphose der Holothurien und Asterien.
Ibid. 1849-50.

Anatomische Studien fiber die Echinodermen. Muller's Arch. 1850.

Hft. II.

Berichtigung und Nachtrag zu den Anatomischen Studien fiber die
Echinodermen. Ibid. Hft. III.

Fortsetzung der Untersuchungen fiber die Metamorphose der Echinoder-
men. Ibid. Hft. V>

Ueber die Ophiurenlarven des Adriatischen Meeres. Ibid. 1851. Hft. I.

Ueber die Larven und die Metamorphose der Echinodermen, vierte Ab-
handlung. Bead to the Berlin Acad. 7, Nov. 1850; 28 April and 10
Nov. 1851, and published in 1852.

Agassiz. Twelve Lectures on Comparative Embryology, delivered
before the Lowell Institute, in Boston, Dec. and Jan., 1848-49. Boston,
1849.

Busch. Beobachtungen fiber Anatomif? und Entwickelung einiger wir-
bellosen Seethiere. Berlin, 1851.

These writings relate chiefly to development ; but, for many special points
of Anatomy, see the writings of Muller , Krohn, Peters, and others referred
to in my notes. — Ed.

«.

CHAPTER I.

CUTANEOUS ENVELOPE AND SKELETON.

§ 72.

With the exception of the apodal Sipunculidae, the Echinoderms have a
cutaneous skeleton modified in the different orders in the following man-

ner:

§ 72. THE ECHINODERMATA. 77

I. In the Holothurioi'dea, irregular calcareous corpuscles, which often
have reticulated openings, are scattered through the skin.®

II. In the Echinoidea, the calcareous substance is separated from the soft
skin, and composed of plates of a definite form, pierced by openings.
These plates are immovably united together by means of sutures. These
last are easily seen in the Echinidae, but are indistinct in the Clypeastri-
dae; they entirely disappear with age in some species.® Among these
plates which are arranged in a regular series, those called ambulacra i
should be mentioned ; these are perforated, having upon their outer sur-
face the pedicles, and upon their inner the ambulacral vesicles. They
form, usually, five double rows, so placed between the other plates that
their openings form, sometimes five longitudinal rows extending from the
mouth to the arm,® sometimes a rosette of five lobes (4> on the dorsal sur-
face of the skeleton.®

III. The coriaceous skin of the Asteroidea, like that of the Holothurioi-
dea, contains numerous calcareous corpuscles, of which the smallest are
irregular, the largest porous.’ But beneath this is a cutaneous skeleton,
composed of porous calcareous pieces, movably articulated, and extending
on the ventral surface from the mouth to the end of the rays.

In many .species, the larger corpuscles, pressed together, form a reticu-
lated support, which is either simple® or composed of plates.®

With the internal skeleton, each articulation is usually composed of
many pieces, the intervening lacunae of which are the ambulacral pores.
The principal middle pieces unite at an obtuse angle, thus forming an
abdominal furrow.® The Ophiuridae have also an articulated internal
skeleton, but the articulations are simple. But the external envelope of
their arms consists of calcareous scales, closely knit together, and which so
tightly close up the internal skeleton that the cavity of the body does not
extend between the skin and the internal skeleton into these appendages,
as in the Asteroidae.

IV. In the CrinoVdea, the skin is soft only on the ventral surface ; that
of the back is wholly calcareous, and converted into an articulated skele-
ton, which extends upon the arms and lateral branches. The mobility of
these articulations is due to an elastic, interarticular tissue. They consti-
tute discs or short cylinders, which, joined together, form arms, lateral
branches ( pinnulae ), cirri, and in some species a peduncle.®

There is a canal in axis of all these parts of the skeleton, and upon the

1 These irregular and usually perforated calca-
reous corpuscles are mixed with the sand of the
sea, after the death and decomposition of the ani-
mal, but can then easily be distinguished with the
microscope. Quatrefages (Ann. d. Sc. Nat.
XVII. 1842, PI. III. IV.) has figured many of them
belonging to Synapta. Similar microscopic cor-
puscles, of various forms, are found in the soft
parts of most of the Echinoderms. It is very
desirable that, as has already been commenced by
Ehrenberg (Abhandl. d. Berl. Akad. 1841, p. 408),
they should be subjected to careful investigation 5
for by this way alone can correct views be ob-
tained ujrtm many enigmatical bodies of this kind
seen by the naturalist.

For the calcereous corpuscles imbedded in the
skin of the Holothurinae, see Koren in Froriep's
neue Not. XXXV. p. 18, fig. 6-9 5 and in the
Arch, skandin. Beitr. f. Naturg. I. p. 449.

7#

2 Scutella and Clypeaster,

3 Echinus and Cidaris.

4 Encope, Rotula , Scutella , tyc.

5 A very detailed description of the shell of
Echinus will be found in Mechel's System der
vergleich. Anat. II. Abth. 1, 1824, p. 31 5 and in
the monograph of Valentin , Anat. du genre
Echinus, 1841, p. 5. He has also published very
exact researches, with figures, upon the intimate
structure of the calcareous plates of this animal
(Ibid. p. 17, PI. II.).

6 Aster acanthion , Solaster.

7 Aster acanthion, Oreaster , Solaster , fyc.

8 See the figure by Sharpey , Cyclop. Anat. and
Phys. loc. cit. p. 31, fig. 8, 9 5 and Meckel's ver-
gleich. Anat. II. Abth. 1, p. 19.

9 Pentacrinus .

THE ECHINODERMATA.

78

§§ 73, 74.

ventral surface of the arms and pinnulae, a furrow, over which the soft
skin ( perisoma ) passes iu a bridge-like manner. a0)

§1-70

ID.

In many Echinoidea the buccal cavity is provided with processes point-
ing perpendicularly into the interior of the shell, and which are the
points of attachment of the masticatory muscles and ligaments.

This osseous circle is most developed in the Echinidae.® and is com-
posed of five processes. Between each of these is a smaller one, corre-
sponding to as many ambulacra! ones, each of which is perforated by
a large opening.® In the Clypeastridae. there are five simple processes
only;® and in the Spatangidae they are wholly absent.

The sub-cutaneous osseous ring about the oesophagus, in the Holothuri-
oi'dea, corresponds probably to this circle. Usually composed of ten pieces,
it may be regarded as a rudimentary, internal skeleton, for it is the point
of attachment of both muscles and tentacles.

In Hnlothuria tubulosa its anterior border is denticulated;® and in
Synapta it is composed of twelve pieces, five of which have oval openings
for the free passage of the aquiferous canals. ®

§74.

The general envelope of many Asteroldea is more or less covered with
various calcareous productions. These have the forms of lamellae, knobs,
callosities, granules, immovable rays both sharp and blunt, rough and
smooth movable points, double hooks, &c.(1)

In the Echinoidea, there are points of very variable size united to
knobs which are scattered over the external surface of the shell. These
points project through the thin skin covering this shell, having at their
base a kind of capsular articulation.®

Bemarkable cutaneous organs are found in Synapta. These are small
anchor-like hooks, by which these animals attach themselves to objects.
Each of them is obliquely inserted under a small sub-cutaneous scale,
which is perforated by a canal.®

10 In the Crinoi'dea, as well as in the Echino-
derms generally, the parts of the skeleton have a
calcareous, reticulated structure ; see Muller's
Arch. 1837, p. 93, and Ueber d. Bau. d. Pentacri-
nus caput Medusae, in the Abkandl. d. Berl. Akad.

1841, Taf. I. fig. 3.

1 Echinus , Cidaris.

2 Valentin , Monogr. loc. cit. PI. II. fig. 15.

3 Agassiz, Monogr. d’ilchinodermes, 24e Livr.
containing the Scutellal , PI. XIII. fig. 3, PI.

XXVII. fig. 7 ( Lobophora and Echinocyamus).

4 Tiedemann , Anat. d. Rcihrenholothurie, &c.,
p. 26, Taf. II. fig. 5 *, also Wagner , Icon. zoot.

Tab. XXXII. fig. 15.

Korea has observed that the osseous ring is
composed of ten pieces with Thy one fuscus and
Cuvieria squamata of the Holothurinae.

0 Quatrefages , Ann. d. Sc. Nat. XVII. 1842,
p. 47, PI. IV. fig. 5 •, PI. V. fig. 7, c. c.

1 With Oreaster and Culcita , the whole body is
covered with knobs and granulations. With As-
tropecten and Stellasler, you find flattened points
and marginal lamellae. Innumerable rays, with

bristled points, project from the surface of So -
laster and Chaetaster. With Ophiocoma and
Ophiomastix , the margins of the arms are covered
with smooth 'points, which in Ophiothrix are
spinous. In Ophionyx these spinous points have
movable double hooks ; see the beautiful figures
of Midler and Troschel (System d. Asteriden).

2 The spines of the Echinoidea have, over their
whole extent, numerous, denticulated ribs ; see
Valentin , Monogr. loc. cit. PI. III. fig. 26. In
Spatangus the spines are spatulate, and in the
Clypeastridae ( Mellita , Encope , Laganum ) they
are clavate. The minute researches of Valentin
(Monogr. loc. cit. p. 24, PI. Ill) have shown the
structure of the spines of the Echinoidea to be very
complex.

3 The burr-like roughness of the skin of Synapta
has already been observed by Eschscho/tz (Zool.
Atlas, Hft. 2, 1829, p. 12). Jaeger (De llolothu-
riis dissertatio, 1833, Tab. I. fig. 3) first figured
the cutaneous books of Synapta Beselii. Quatre-
fages (Ann. d. Sc. Nat. XVII. p. 33, PI. III.) has
given a vox -y exact description of those of Synapta

§§ 75, 70.

THE ECIIINODERMATA.

79

§75.

A peculiar calcareous plate (the madreporic plate) is observed upon the
cutaneous skeleton of the Asteroidea and Echinoidea. In the last it is
always situated in the centre of the dorsal surface, but in the first its
position varies. In the proper Asteroidae there are often several, having
an excentric dorsal situation ; while in the Ophiuridae® it is found upon
the ventral surface, and especially in the angle formed by the junction of
the two arms with the tortuous mouth. In some Asteroidae a membra-
nous sac (stony canal), filled with organized calcareous particles, is attached
to this plate ; in others, an articulated calcareous cord stretches obliquely
across the body towards the border of the mouth. The use of these parts
is not yet positively known.®

CHAPTER II.

MUSCULAR SYSTEM AND ORGANS OF LOCOMOTION.

§76.

In the Echinoderms the muscular system is well developed. Its primi-
tive fibres are flat, and without transverse striae. (1>

In the ventral surface, and between each joint of the arms and pin-
nulae of the Crinoidea, there are one or two small muscles, antagonistic to
which, upon the opposite surface, is an interarticular elastic tissue.®

In the Asteroidea, the interarticular lacunae of the internal skeleton are
filled with muscles.® The skin of these animals does not aid the motions
of the arms, except by its elasticity. But in the Echinidae the skin

Duvernaca. The similar hooks found in the sea-
mud of Vera Cruz have been taken by Ehrenberg
for stony concretions belonging to a sponge, and
figured and named Spongolithis anchor a (Ab-
hand. d. Berl. Akad. 1841, p. 323, Taf. III. No.
VII. fig. 36). He has also taken the perforated
supports of these hooks for an Infusorium with a
siliceous carapace, described as Dictyocha sp lea-
dens (Ibid. tig. 35). But, more lately, he has
perceived their true nature (Ibid. p. 407, 443).
The discovery of analogous cutaneous organs in the
marl near Streitberg, by Count Munster (Beitr.
z. Petrefafe lift. VI. 1843, p. 92, 96, Taf. IV. fig.
9), is very interesting, since it shows the antedilu-
vian existence of Synapta.

Beside the cutaneous corpuscles of carbonate of
lime, Quatrefages (loc. cit. p. 36, PI. III. fig. 15)
has found others which are of a spherical form in
the skin of Synapta Duvernaea ; and, as they
have protractile filaments, lie compares them to
nettling organs.

1 Astrophyton.

2 These parts are found in Astropecten. Ac-
cording to Tiedemann (loc. cit. p. 54), they furnish
the necessary calcareous matter for the skeleton of
the Asteroidae. But Ehrenberg {Muller's Arch.

1S34, p. 580) has shown that they do not contain or-
dinary calcareous matter, but rather that which is
organized and perforated in a reticulated manner.
A calcareous cord of a special structure is found in
Aster ac antliion ; see Siebold, Muller's Arcli.
1836, p. 291, Taf. X. fig. 14-18 ; and Sharpey ,
Cyclop. Anat. &c. loc. cit. II. p. 35, fig. 12, 13, s.*

1 According to Wagner {Muller's Arch. 1835,
p. 319), the Echinoderms do not have transversely
striated muscles. This has been confirmed by
Muller (Abhand. d. Berl. Akad. loc. cit. p, 214, Taf.
IV. fig. 9) in the genera Pentacrinus and Coma-
tula. For my own part, I have failed to perceive
them in Echinus , Asterias , Ophiurus , Holothu-
ria, and Si pun cuius. Valentin (Monogr. loc. cit.
p. 101, PI. VIII. fig. 153-155) asserts to have
seen striae upon the fibres of the masticatory, spin-
ous and anal muscles of Echinus ; and Quatre-
fages (Ann. de. Sc. Nat. loc. cit. p. 43, PI. III.
fig. 17) has observed transverse wrinkles during the
contraction of the lortgitudinal muscles of Synapta.

2 Muller , Abhand. d. Berl. Akad. loc. cit. p. 214,
220, Taf. II. fig. 8, 12.

8 The interarticular muscular layer of the
Asteroidae has been accurately described by
Meckel (System d. vergleicli. Anat. III. p. 14).

* [§ 75, note 2.] See, for further details on this stone-canal with the Ophiuvidae, Muller , Arch. 1850,
p. 122. — Ed.

THE ECHINODERMATA.

80

§ 77.

covering the shell has distinct muscular bands for the motions of the
points. <4)

In the Holothurioi'dea and Sipunculoidea there is a very thick sub-
cutaneous muscular layer. This is itself composed of two layers, — the first
and upper being made up of circular, the second and lower of longitudi-
nal fibres. In the Holothurioi'dea, <5) these fibres form five large, thick,
widely-spread bundles, which are inserted into the osseous ring. In the
Sipunculoidea, these bundles are more numerous, but more compactly
bound together.®

The muscles of mastication, of the digestive canal, and of the tentacles,
will be treated hereafter.

§ 77.

With the exception of the Synaptinae and Sipunculoidea, the Echinoderms
have special, tentacular, locomotive organs (ambulacra). These are hollow
and very contractile prolongations of the skin, and communicate through
the ambulacral pores with small contractile sacs (ambulacral vesicles), found
upon the internal surface of the coriaceous or calcareous envelope of the
body. The ambulacra and their vesicles have transverse, longitudinal fibres,
and contain a clear liquid, which, from contractions, oscillates from one to
the other through the pores. In this way the ambulacra are capable of
erection and elongation, and the animal uses them as feelers to find a
proper object of attachment ; and on this account, also, they have in some
species a suctorial extremity.

These organs, which are sometimes locomotive, sometimes prehensile,
have the following variations of structure and form :

I. With the Crinoidea they are small, delicate and cylindrical, and are
found upon the borders of a furrow, which runs from the mouth along the
soft perisoma covering the arms and pinnulae. Each one of them is cov-
ered with small cylindrical, clavate tentacles. a)

II. The Ophiuridae have upon their arms, and between the plates, pores
which connect with small cylindrical ambulacra ; these last, from numerous
small warts, present a studded aspect.®

III. With the Asteroidae they are situated in a double or quadruple
row, in the ventral furrows which extend from the mouth to the end of the
rays. They form compact cylinders of considerable size, the acute or
truncated extremity of each of which has a sucker.®

IV. With the Echinoidea they are situated upon an elongated stalk,
and have a sucker. They are found both upon the ambulacral plates and
immediately around the mouth.® Being extremely movable, they are

4 Valentin , Monogr. loc. cit. p. 35, PI. III. fig.
39.

5 The cutaneous muscular system of Holathuria
has been described by Tiedemann (loc. cit. p. 27,
Taf. II. IV.) 5 anti that of Synapta by Quatre-
fages (Ann. d. Sc. Nat. loc. cit. p. 41).

6 For the muscular system of Sipunculus nu-
dus , see Grube , in Muller's Arch. 1837, p. 240,
Taf. XI. fig. 1.

1 The ambulacra of Comat ula, which have ac-
tive vermicular movements, have no opening at
their free extremity ; see Miiller , Abhand. d. Berl.
Akad. loc. cit. p. 222, Tab. IV. fig. 13, 14.

By these the very active arms of the Ophiuri-

dae are attached to surrounding objects 5 see
Erdl in Wiegmann's Arch. 1842, I. p. 58, Taf.
II. fig. 1, a.

3 Beside the very correct description given of
these organs by Tiedemann (loc. cit. p. 56), see
Rymer Jones (A Gen. Outl. of the Anim. King,
p. 148, fig. 65). It appears that* in Astropecten
the extremity of the ambulacra can be inverted,
thus compensating for the sucker found in Echi-
naster , Asteriscus , and Aster acanthion.

4 With Echinus the suckers, which exactly re-
semble the other ambulacra, are fixed upon the
contractile membrane surrounding the mouth.

With Spatangus and Echinanthus there ia

THE ECHINODERMATA.

81

§ 78.

chiefly locomotive; for from them numerous points are prolonged, by
which they adhere to objects, and to which they become afterwards fixed
by their sucker. They are covered with ciliated epithelium, and their
suckers are made firm by a coarse calcareous network. Elongated cal-
careous corpuscles of the same nature are found also in their walls, —
some branching and others hook-like.®

V. With those Holothurioidea which have them, they have a more or
less complete sucker, and are scattered irregularly over the entire surface
of the body, or disposed in regular rows. Usually very short, they can be
retracted deeply in the skin ; but they are capable of equal prolongation,
and thus perform well the function of suckers.®

The ambulacral vesicles, which are intimately connected with the circu-
latory and respiratory systems, will be fully treated hereafter.

§78.

With the Echinoidea, and Asteroidae, there are other movable organs
(pedicellariae), which, scattered over the surface of the body, are prehen-
sile, and used in a pincer-like manner. With the Asteroidae, they usually
consist of two delicate forceps-like pieces (pedicellariae forcipatae), or of
two large valvular flaps (pedicellariae valvulatae). Generally they are
not pediculated.® Those of the Echinoidea have been carefully studied
in Echinus. They are numerous, and occur for the most part about the
mouth, presenting three different forms: 1. Those composed of three
short, lenticular pieces (pedicellariae gemmiformes). 2. Those formed of
three long delicate pieces, laterally denticulated (pedicellariae tridactyli).
3. Those with three laterally denticulated spoon-like pieces (pedicellariae
ophiocephali). They are supported by a base of calcareous, reticulated
substance; and in the Echinoidea, always rest upon a stalk, the lower part
of which contains a cylindrical, calcareous nucleus, while the remaining
portion is soft, and capable of a spiral contraction.® Here also they are
covered with ciliated epithelium, and can, by means of movable processes,
seize hold of objects, which, being passed along, may be conveyed even
from the dorsal surface to the mouth.

near the mouth, and opposite the ambulacral
rosette, a row of ambulacra having special pores.

5 See Valentin , Monogr. loc. cit. p. 37, PI. IY.

V., and Erdl in Wiesmann's Arch. 1842, I. p.

55, Taf. II. fig. 10. The corpuscles found by
Ehrenberg (Abhandl. d. Bed. Akad. 1841, p. 324,

Taf. III. No. VII. fig. 37, a. b.) in the marine
sand of Vera Cruz, and figured under the name
of Spongplithis uncinata , are only the cruciform
parts of the skeleton of Echinus. This will be
evident from comparing them with the calcareous
corpuscles figured by Valentin (Monogr. loc. cit.

PI. V. fig. 65).

6 Catalogue of the Physiol, series of Comp.

Anat. contained in the Royal Coll, of Surgeons,

London, IV. 1838, p. 196, PI. XLIX. fig. 3-5.

1 With Luidia, there are, however, three tongue-
like pedicellariae. In Aster acanthion , they have
a soft pedicle. In Asteropsis , Stellaster, and

* [ § 78, note 2.] See Adams (Ann. of Nat.

Hist. VIII. 1851, p. 237), who has found what he
regards as Podicellariae on the skin of Voluta

Astrogonium1 they are valvular and without a
pedicle ; see Muller and Troschel , loc. cit. p.
10, Taf. VI. fig. 3-6.

The pedicellariae of Echinus were, at first,
taken for parasitic Polypi by O. F. Muller (Zool.
Dan. I. 1777, p. 16, Tab. XVI.). See Lamarck ,
Ilist. Nat. des Anim. sans Vert^bres, II. p. 75.
More recently, Agassiz ( Valentin's Monogr. loc.
cit. p. 51) has expressed the opinion that they were
young individuals. The researches of Delle Chiaje
(Memor. sulla storia e notom. degli Anim. senza
Vertebr. II. 1823, p. 324, Tab. XXIII.) and of
Sars (Beskrivelser, &c., p. 42, Tab. IX.) upon
Echinus , Cidaris , and Spatangus , have dispelled
all doubts as to the real nature of these organs.
Very correct descriptions of them have lately been
published by Valentin (Monogr. loc. cit. p. 46,
PI. IV.), and by Erdl ( Wiegmami's Arch. loc.
cit. p. 49. Taf. II. fig. 1-9).*

vespertilio ; he thinks, therefore, that they are
independent parasitic organisms. — Ed.

82

THE ECHINODERMATA.

§§ 79, 80.

CHAPTER III.

NERVOUS SYSTEM.

§ 79.

The central portion of the nervous system consists of a ring which is
usually pentagonal, and surrounds the commencement of the oesophagus.
The main nervous branches are given off from this, and pass to the other
end of the body along the median line of the rays, or their corresponding
parts. The form of this ring is mainly due to that of the mouth ; and
therefore, with the reniform mouth of Spatangus, it is unequally pentago-
nal.05 Ganglia have not yet been found in it. But in Echinus and Holo-
thuria, the nerves passing from it have between their fibres, violet, green,
or red pigment granules.®

§80.

The principal nervous trunks have a longitudinal furrow, as if composed
of double cords, and give off from each side, during their course, branches
which go to the ambulacra.®

With the Crinoidea, a nervous cord passes beneath the furrow formed
by the perisoma on the ventral surface of the arms ; this has a slight
swelling opposite each pinnula, to which it sends off a branch.® With
the Asteroidae, the nervous trunks which pass off from the oesophageal ring
are lodged in the ventral furrows of the rays.® But in the Ophiuridae,
they pass in a canal, concealed by the ventral plates of the arms. The
five nerves, analogous to those of the Echinoidea, pass along the internal
surface of the ambulacral plates, between the vesicles, even to the centre
of the dorsal region. In Echinus, there are, moreover, special nerves
directly from the oesophageal ring, for the organs of mastication and
digestive canal.® In Holothuria, this ring is situated directly on the
anterior border of the osseous circle, and sends off' five nerves which pass
along the median line of the longitudinal muscles, even to the end of the
body ;(5) it sends off also special nerves to the oral tentacles.®

1 Krohn ( Muller's Arch. 1841, p. 8, Taf. I. fig.
3,4).

2 Krohn , loc. cit.

1 Krohn , ibid. p. 4, 10.

2 Muller (Abhandl. d. Berl. Akad. loc. cit. p.
233, Taf. IV. fig. 11, i. ; Taf. V. fig. 16).

3 The nervous system of the Asteroidae was first
clearly shown by Tiedemann (loc. cit. p. 62,
Taf. IX. and MeckeVs Deutsch. Archiv. I. 1815,
p. 69, Taf. III. fig. 1). This anatomist, like
Krohn (loc. cit. p. 4), did not perceive the ganglia
of the oesophageal ring, observed by Wagner
(Vergleich. Anat. 1834, p. 372).

The ganglia and nerves that Spix (Ann. du
Mus. d’Hist. Nat. XIII. 1809, p. 439, PI. XXXII.
fig. 3, 6) and Konrad (De Asteriarum fabrica
dissert. 1814, p. 13, fig. 3, o.) affirm to have seen
on the internal (dorsal) surface, opposite the ventral

* ( § 80, note 6.] Muller has furnished some
valuable contributions on the nervous system of the

furrows of the articulations of the rays, in Aster-
acanthion rubens , and glacialis , are probably
only tendinous fibres.

4 Krohn , who has studied the nervous system
of Echinus and Spatangus , has traced the fila-
ments given off from the main trunks, across the
ambulacral pores, to the suckers of the ambulacra.
See also Valentin's figures of tliis system, in
EchinHs (Monogr. loc. cit. p. 98, PI. VIII. IX.).

5 The oesophageal ring of Holothuria , observed
by Krohn (. Muller's Arch. 1841, p. 9, Taf. I. fig.
5), sends off its principal nerves across the fissures
of the dentations of the five great pieces of the
osseous rings. Then* lateral filaments, going to the
ambulacral vesicles, are so fine that Krohn could
scarcely find them.

0 Grant , loc. cit. p. 184.*

Ilolothurioidea ; see Arch. 1850, p. 226. lie
makes this statement, which is worthy of remem-

THE ECHINODERMATA.

83

$ 81.

With the Sipunculidae, as with the other worm-like Echinoderms which
approach the Annelids, the arrangement of the nervous system is quite
different. . Here, the nervous ring is a simple, aganglionic thread extend-
ing to the posterior end of the body, and may be regarded as the first trace
of a ventral cord.®

CHAPTER IV.

ORGANS OF SENSE.

§81.

The sense of touch is well developed with the Echinoderms, and seems to
have its seat in the oral tentacles, the ambulacra, and pedicellariae.

With the Asteroidea, and Echinoidea, no organs of vision have yet been
found. As such, however, have been regarded the red pigment dots sit-
uated, with the former, at the extremity of their rays,(1) and with the latter,
in the middle of the dorsal region upon five ocellary plates which alternate
regularly with those of the genital organs.® These ocellary plates are
perforated each by a very fine canal, through which passes a delicate fila-
ment from -the main nerve for the pigment dot.® Although these pigment
dots have thus a nervous connection, no proper organ to refract the light
has yet been found in them.(4)

1 According to Krohn ( Muller's Arch. 1839,
p. 348), the oesophageal ring of Sipunculus nudus
has two super-oesophageal ganglia blended to-
gether. These had already been observed by
Delle Chiaje (Memor. loc. cit. I. p. 15, Tav. I.
fig. 6. i.)j but more lately Grube had taken them for
cartilaginous rudiments of the osseous circle
(Muller's Arch. 1837, p. 244). He has also con-
founded with the muscular system the two lateral
nerves of this ring, and its abdominal branch
which in its course sends off laterally branches to
the muscular layer and to the skin, and termi-
nating at the end of the body in a swelling. Then,
on the other hand, the filaments surrounding the
digestive tube, and taken by him for nerves,
appear to be only cellular fibres (loc. cit. p. 244,

Taf. XI. fig. 4).

According to Forbes and Goodsir ( Froriep's
neue Not. No. 392, 1841, p. 279), the nervous sys-
tem of Echiurus is composed of an oesophageal
ring, with an abdominal cord, from which pass off
asymmetrical branches.

brance : “ It is a noticeable fact that the nervous
trunks of these animals throughout are contained
in a sheath, which, after the maceration of its
contents, has exactly the aspect of a blood-vessel.”

The nervous system of these animals cannot, there-
fore, be properly studied fi;om alcoholic speci-
mens. — Ed.

* [ § 80, note 7.] See also Blanchard (Ann. d.

Sc. Nat. 1849, XII. p. 57), who has well made out
the nervous system with Sipunculus rufo-Jim-
briatus. It consists of two cerebral ganglia

According to Quatrefages , Echiurus Gaertneri
has an abdominal cord which possesses ganglia,
and by this character the Echinidae approach the
Annelida *, see Ann. d. Sc. Nat. VII. 1847, p.
332, PI. VI. fig. 4*

1 In the Clypeastridae and Echinidae.

2 These dots, which Vahl (Muller Zool. Dan.
Tab. CXXXI.) had already observed in Ptcraster
militarise were first regarded as eyes by Ehren
berg (Muller's Arch. 1834, p. 577, and Abhand.
d. Berl. Akad. 1835, p. 209, Taf. VIII. fig. 11, 12).
He has seen in Asteracanthion violaceus , a small
swelling at the extremity of the nerve of the ocel-
lary dot. Forbes (Hist, of the Brit. Star-fishes,
1841, p. 152) first noticed these dots in Echinus ,
and their presence has been confirmed by Agassiz
and Valentin (Monogr. loc. cit. p. 10, 100, PI.
II. fig. 12, PI. IX. fig. 188, 189).

3 Valentine loc. cit. PI. IX. fig. 190.

4 Valentin has failed to discover in these organs
a crystalline lens. Although in Echinus they are
upon the back, and therefore favorable to vision ;

united so as to form a single cordiform mass — the
brain, which is situated under the muscles of the
proboscis. From this brain passes off a cord on
each side, forming a collar about the oesophagus }
these unite below, and then continue as a ventral
cord to the posterior extremity of the body. This
cord has slight swellings along its course, which
may be regarded as ganglia *, they send nerves to
the integuments.

This anatomist has also observed here a very
distinct splanchnic system of nerves. — Ed.

84

THE ECHINODERMATA.

$$ 82, 83.

CHAPTER Y.

DIGESTIVE APPARATUS.

§ 82.

The alimentary canal is situated in the cavity of the body, isolated, but
is retained in its place by a kind of mesentery which is composed of
fibres/1' or of a thin membrane/2'

The mouth, which is usually central, is often surrounded by a circle of
tentacles/3’ In the Asteroidea, the digestive canal is a large central pouch,
an anus and appendages extending into the rays being present in some(4)
and wanting in others/5' In the other Echinoderms, the digestive canal has
usually thin walls, is of a variable length, and tortuous quite to the anus.

The position of the anus is quite varied. In the Echinidae, and Aste-
roidae, it is in the centre of the back, exactly opposite the mouth. In the
Holothurioidea, it is at the posterior end of the body ; while in the
Clypeastridae, and Spatangidae, it opens laterally upon the margins of the
shell. In the Crinoidea, it is near the mouth upon the ventral surface, and
in the Sipunculoidea, it has a similar position.

The internal surface of this canal has generally been found lined with
ciliated epithelium/3'

§83.

With the Asteroidea, and Echinoidea, the pedicellariae already described,
are used to seize the food and convey it to the mouth. Their ambulacra
are perhaps sometimes used in the same way. In the Crinoidea, the fur-
row of the tentacles, aided by the tentacles themselves, serves well to con-
duct the food from the arms and pinnulae to the mouth/1'

In the Holothurioidea, and Sipunculidae, there are completely retractile
tentacles of a special nature. In the first, they are hollow, pinnated or
branched, and, arranged in a circle around the mouth, are attached by
their base to the osseous circle and to the elongated vesicles which project
into the cavity of the body. These tentacular vesicles contain a liquid,

and, in the Asteroidae, where they are upon the
ventral surface at the end of the furrows, the rays
bend round to the dorsal surface ; and again,
although Tiedemann {Meckel's Deutsch. Arch,
loc. cit. p. 175) thinks these last can distinguish
light from darkness, yet it is doubtful if these ani-
mals can really see by these organs. They appear,
like many other inferior animals, to perceive the
light by its action as an excitant upon their skin,
and in this way can, like plants, seek the sun-
Light. The account wliich Forbes (Hist, of British
Star-fishes, p. 139, and Froriep's neue Not. No.
420, 1841, p. 26) has given of Luidia fragilis-
sima , which, having made its escape by the loss
of an arm, looked with scornful eyes upon its per-
secutor, is pleasant to read, but is far from set-
tling this question.

l Asteroidea, Echinoidea, and Sipunculoidea.

2 Holothurioidea.

3 Holothurioidea and Sipunculoidea.

4 Asteroidae.

b Ophiuridae.

6 According to Sharpey (Cyclopaedia, &c., loc.
cit. I. p. 616) and Valentin {Wagner's Hand-
wdrterbuch der Physiol. I. 1842, p. 493), the inter-
nal surface of the stomach and its appendages, of
the Asteroidae, has a ciliary movement. Valentin
(Monogr. &c. p. 79) has also found ciliated epithe-
lium in the entire digestive canal of Echinus.

With Phascolosoma , where I have found cilia
upon the tentacular apparatus, and with Coma-
tula, where Muller (Abhandl. d. Berl. Akad.
1841, p. 233) has found them in the anus, they
extend probably through the intestine.

1 Muller , Abliandl. d. Berl. Akad. 1841, p. 222.

§ 84.

THE ECIIINODERMATA.

85

which, by their contraction, is pressed into the cavity of the tentacles for
lubrication/2'

The retraction of the tentacles is due in part toiheir own contractility,
and in part to the numerous muscles, which, arising from the internal sur-
face of the cavity of the body, are inserted into the osseous circle. By
these means, it, together with the tentacles, can be retracted into the
body/3' With the Sipunculidae the tentacular apparatus consists of a
fringed border on the margin of the mouth, which is also provided
with vesicles/4’ In Sipunculus, and Phascolosoma, there are four long
muscles, which, arising from the internal surface of the body, pass on to the
mouth, and are retractors of the tentacular membrane/5' It is possible
that these oral tentacles serve not only as prehensile organs of food, but
also as those of locomotion and respiration/61

§ 84.

The mouth of the Comatulinae presents nothing remarkable ; but with
the Asteroidae, it is covered with hard papillae, projecting from its corners
and angles. In the Ophiuridae, the inverted angles are covered with hard
papillae, while the everted ones have calcareous teeth, between which are
concealed soft cylindrical tentacles. Immediately behind all of these, the
entrance of the stomach is indicated by a membranous sphincter. In the
Asteroidae, however, this is wanting, there being a short oesophagus leading
directly into the stomach.

With the Echinoidea, and Holothurioi’dea, the mouth has a soft circular
lip, between which, with the Echinidae, and with the Clypeastridae, pro-
ject the points of enamelled teeth.

The mouth of the Echinidae, and Clypeastridae, has a very remarkable
masticatory apparatus. In the first, the calcareous basis which supports the
teeth has long been known as Aristotle's lantern. This conical basis is
divided into a base and summit ; the first being the superior part of the
animal itself, while the second is formed by points of teeth projecting
from the mouth. It is, moreover, composed of fifteen pieces, five of which
are three-sided, hollow pyramids, and so adjusted that they touch each
other by their plane surfaces, presenting externally the third surface which
is convex. This last has internally a longitudinal furrow, in which is fitted a
very long, narrow and slightly-curved tooth. Beside these five principal
pieces, which form the jaws of Echinus , there are two other kinds, much

2 These vesicles are found in Ho/othuria and
Chiroddta ; see Tiedemann , loc. cit. Tab. II. fig.
4, e. 6, i. ; also the Catalogue of the Museum, Lon-
don, &c., IV. Id. XLIX. fig. 1, 2 ( Holothuria tubu-
losa ) •, and the Atlas Zool. du Voyage de 1’ Astrolabe.
Zoophytes, PI. VIII. fig. 3 ( Chirodota fusca).
In Pentacta doliolum , I have found only a single
cylindrical vesicle fixed to the circle of tentacles.
In Synapta Duvernaea ( Quatrefages Ann. d.
Sc. Nat. loc. cit.), these vesicles are entirely want-
ing.

Cuvier (Anat. Comp. V. p. 454) and other anat-
omists (see Grant , Outlines, &c., p. 333) have
erroneously taken these parts for salivary organs.
They do not communicate with the digestive canal,
but connect freely with the circulatory and respir-
atory systems, — a point, therefore, to which we
shall further allude hereafter.

s

3 In Pentacta , there are five large cylindrical
muscles arising from the subcutaneous longitudinal
ones, and inserted into the osseous circle *, — they
are special retractors of the tentacles ; see Meckel ,
System d. vergleich, Anat. IV. p. 62.

4 I am inclined to regard as tentacular the two
vesicles of Poli, in Sipunculus ; and of which
Delle Chiaje (Memor. &c. Tav. I. fig. 6, d.) per-
ceived only one, although Grube (Muller's Arch.
1837, p. 251, Taf. XI. fig. 2, P.) has seen them
both fixed in a space circumscribed by the tentac-
ular membrane.

5 Grube , Ibid, p. 241, Taf. XI. fig. 1, u. 2, m. m.j
and Delle Chiaje , Memor. &c. Tav. I. fig. 3.

<> The oral tentacles of Synapta Duvernaea ,
which, according to Quatrefages (loc. cit. p. 63,
PI. IV. fig. 1), have suckers on their internal sur-
face, are certainly used as locomotive organs.

86

THE ECHINODERMATA.

§ 85.

smaller. Of these, five are elongated quadrilateral plates, placed at the
base of the lantern, between each two pyramids. The other five, smaller
and longer, are curved upon the first.

All these pieces ar$ united by many tendons and muscles to each other,
and to the neighboring osseous circle which projects inwards from the shell.

The muscles of mastication are in ten pairs ; five of these arise from the
longest processes of the osseous circle, and are inserted on the pyramids
below the summit of the lantern. The other five, on the other hand, pass
from the shortest processes of this circle to the base of the pyramids.

By this arrangement, when the first five contract and separate the sum-
mits of the pyramids together with their teeth, the second five, contracting
also, carry the points of the teeth again together, by separating the bases
of the pyramids.®

In the Clypeastridae, the masticatory apparatus is more simple. It is
composed of ten unequal, triangular pieces, joined together, Y-form, two
and two. Each of these pieces has in its projecting angle, a furrow in
which a tooth is fitted. These five jaws are so arranged around the mouth
that their angles and the points of their teeth meet together in its centre.®

§ 85.

The digestive cavity of the Ophiuridae is only a simple stomachal sac,
occupying the centre of the hollow disc of their body.

It is divided by walls projecting inwardly, into many caeca, which never
extend into the rays.®

There are usually ten of these caeca, which in Astrophyton are subdivided
into numerous smaller caeca.®

With the Asteroidae, the stomach is large and has a similar situation;
but it sends off radial caeca into the rays.

In those species which have an anus, the digestive canal may be divided
into three parts. The stomach is separated into two chambers by a circu-
lar, projecting fold. The first of these is the true stomach, and the second
sends off the radial caeca. A narrow, short rectum, passing off from
the stomach, forms the third part of this canal, and terminates in an
anus, situated upon the back of the animal and concealed among points,
callosities, &c. This rectum has folds which, of a variable length and some-
times branched, are called the inter-radial caeca, and are situated between
instead of in the rays.®

In the Comatulinae, this canal consists of a coecum situated at the end
of, a short oesophagus, and which, after a spiral course about the axis of
the body, terminates in an anus having the form of a short tube projecting
from the ventral surface not far from the mouth.®

In Comatula europaea, the axis, around which the digestive canal passes

1 This apparatus has been minutely described by
Tiedemann (loc. cit. p. 72, Taf. X. fig. 1, 2), by
Meckel (Syst. d. vergleich, Anat. IV. p. 56), and
by Valentin (Monogr. &c. p. 63, PI. V.). See
also the beautiful figure by Rymer Jones (Out-
line of the Anim. King. &c. p. 167, fig. 70, 71).

2 Agassiz, Monogr. Ac. 2e Livr. Scutelles. p.
15, PI. XII. XIII. XIV. &c.

1 Konrad , De Asteriarum fabrica, fig. 5.

2 Meckel , Syst. d. vergleich, Anat. IV. p. 50.

3 See also Tiedemann (loc. cit. Taf. VII.), whose
beautiful figures have been copied everywhere ;
and the original designs of the digestive cavity of
Aster acanthion, Archaster, and Culcita , by Mul-
ler and Troschel (loc. cit. Taf. XI. XII.).

4 Upon the digestive canal of Comatula , see
Heusinger , Zeitschr. f. d. organische Physik. III.
1829, p. 371, Taf. X. XI.

THE ECHINODERMATA.

87

§ 86.

spirally, consists of a spongy substance, from which projects a lamina like
the lamina spiralis of the conch of a snail shell.®

In Spatangus, the toothless mouth opens into a delicate (Esophagus .
which passes insensibly into a long tube of nearly the same size. This
last makes two convolutions in its course, and sends off at about its anterior
fourth a very long caecum. The digestive canal, situated between the origin
of this caecum and the (Esophagus, is of a dark color and has transverse
plicae, while the remaining portion below is smooth and of an orange hue.®

In the Clype'astridae, the numerous spiral turns of this canal are sup-
ported by many calcareous laminae situated upon the interior of the shell. ®

In many species of Clypeaster, this canal has at its commencement,
transverse folds, and further on numerous lateral caeca, which are sepa-
rated from each other by laminae like those just described.®

In the Echinidae the pharyngx has very thick muscular walls, and is
surrounded by masticatory organs. Upon it succeeds a proper oesophagus,
which, after a few convolutions, passes to the anus situated in the centre of
the back. The digestive canal is a caecum given off by this last, and
has many spiral turns in the cavity of the body.®

In the Holothurioidea, the very muscular pharynx is surrounded by
the osseous circle. In the Holothurinae, the intestinal canal, which is long
and equal throughout, has many turns from behind forwards, ending at
last in a large cloaca situated at the posterior part of the body. But in
the Synaptinae, it is short and nearly straight, and terminates in an anus
having no cloaca. <10)

In the Echiuridae 5 6 7 8 9 10 (11) this canal closely resembles that of the Synaptinae.

In the Sipunculidae it is long, making its first turn about the middle of
the body, and its second near the posterior extremity. The ascending
and descending portions of this last pass spirally around each other on
their way to the anus which is situated on the ventral surface of the
body.a2)

§ 86.

As to the glandular appendages of the alimentary canal, the salivary
organs are perhaps entirely wanting in these animals.

In the Holothurinae alone, are there particular appendages opening into
its anterior portion, which could be regarded as organs of this nature. In
the different genera, species, and even individuals of this family, these
appendages widely vary as to form and number.

5 Muller , Abhandl. d. Bed. Akad. 1841, p. 230,
Taf. V.

6 See Merkel, Syst. d. vergleich, Anat. IV. p.
55, and Delle Chiaje , Memor. &c. Tav. XXY.

i fig- 12 ; also Carus and Otto , Erlauterungstafeln
z. vergleich. Anat. lift. IV. Tab. I. fig. 25, and
Wagner , Icon. zoot. Tab. XXXII. fig. 8. The
nature of the canal figured by Delle Chiaje is yet
unknown. It arises from the first portion of the
intestine, and returns to it at its middle portion.
It has not been mentioned by Meckel.

7 Agassiz , Monogr. des Scutelles, p. 14, PI. III.
fig. 19, a.

8 Ibid. p. 17, PI. XXII. fig. 28 (Laganum and
Mellita).

9 See Tiedemann and Valentin , loc. cit.

10 The digestive canal of the Holothurinae was

first figured by Delle Chiaje and by T iedemann,

loc. cit. •, afterwards by Quoy and Gaimard (At-
las zool. du Voyage de 1’ Astrolabe. Zoophytes, PI.
VI. fig. 2, PI. VII. fig. 3). The cloaca is always
wholly attached to the skin by numerous tendinous
fibres. In Chirodota fusca the intestine is spiral
(Atlas zool. &c. PI. VIII. fig. 3) ; but in Synapta
Duvernaea it is nearly straight ( Qu.atrefages
Ann. d. Sc. Nat. loc. cit. PI. II.).

11 See the remarks of Forbes and Goodsir upon
the Anatomy of Thafassema and Echiurus ( Fro -
r ley's neue Notizen, No. 392, p. 273, fig. 12).

12 The alimentary canal of Sipunculus nudus ,
and of Echinorhyncus , has been faithfully de-
scribed by Delle Chiaje (Memor. &c. I. p. 9, Tav.
I. fig. 5, 6 *, p. 126, Tav. X. fig. 11) and Grube
(Muller's Arch. 1837, p. 245, Taf. XI.). I have
found a similar intestine in Phascolosoina granu-
lation.

88

THE ECHINODERMATA.

$ 86.

In Holotkuria tubulosa, they are cylindrical, pure white, and very nume-
rous, being united in bundles which are attached to the digestive canal
near the pharynx by short white pedicles. a>

In Pentacta doliolum, there is usually only one of these organs, — a
small, white, curved horn, which sends to the pharynx a very tortuous
canal, which is widely removed from the excretory duct of the genital
organs.

The whiteness of these organs in Holothurinae is due to a reticulated
calcareous skeleton in their walls.®

The radial caeca of the Asteroidae ought probably to be regarded as
hepatic organs. They are often quite developed, extending as a double
canal from the stomach into each ray. Their walls have numerous small
botryoidal vesicles, which secrete a yellow liquid. Usually each of these
ten liver-like organs arises from the stomach by a proper canal ; ® but in
some, two of them connect with this organ by a single canal. (4)

With those Asteroidae which have an anus, there is another series of
glandular appendages, the inter-radial caeca, which pass off from the rectum.
Their function is not yet known. They contain a brownish liquid, in which,
with Asteracanthion rubens, no uric acid has been found. In Astrogonium,
Solaster, and Asteracanthion, these organs are branched, and only two in
number.® In Archaster , and Culcita, there are five ; but in Culcita cori-
acea, each of these is divided dichotomously into two other long botryoidal
caeca, which, separated by a septum, are spread out between the rays.®

In Astropecten,{ 7 which is without an anus, there are sometimes found two
short, analogous caeca, which open into the base of the stomach by a com-
mon orifice. But in Luidia, which is also without an anus, these organs
are entirely absent.®

In the other Echinoderms, which are entirely without these glandular
appendages, the walls of the alimentary canal probably secrete the fluid
requisite for digestion, and thus supply also the want of the hepatic
organ.®

1 It has already been shown that the cylindrical
vesicles of Holothuria taken by Cuvier and other
naturalists for salivary organs do not communicate
with the digestive canal, but rather with the tenta-
cles. The white appendages of Holothuria tubu-
losa were first described as testicles by Delle
Chiaje (Memor. &c. I. p. 97,Tav. VIII. fig. 1. o.),
and Tiedemann (loc. cit. p. 29, Taf. II. fig. 6,
p.) assigned to them the same function. It is cer-
tain that they have no testicular character, although
I cannot affirm that they are salivary organs.
They have been figured, in Holothuria atra, by
Jaeger in his dissertation : De. Holothuriis, Tab.
III. fig. 2, e. e.

2 This calcareous tissue has been observed by
Jaeger (loc. cit. p. 38, Tab. III. fig. 7), by Wag-
ner (F'roriep's neue Not. No. 249, 1839, p. 99),
and by Krohn (Ibid. No. 356, 1841, p. 53). This
last observer, who affirms that these organs are in
connection with the great circulatory vessel sur-
rounding the digestive canal, compares them to the
stony canal of the Asteroidae.

>3 In Astropecten aurantiacus , according to

Tiedemann (loc. cit. Taf. VII. or, Wagner , Icon,
zoot. Tab. XXXII. fig. 1). It is the same, also, in
Archaster , Culcita , and Luidia ; see Muller and
Troschel , loc. cit. p. 132, Taf. XI. fig. 2 ; Taf.
XII. fig. 1.

4 Asteracanthion ; see Konrad , De Asteria-
rum fabrica, fig. 1 ; and Muller and Troschel ,
loc. cit. Taf. XI. fig. 2.

5 See Muller and Troschel , loc. cit. p. 132, Taf.
XI. fig. 1 ( Asteracanthion rubens)-, an entire
group of these rectal coeca of Asteracanthion
glacialis , has been figured by Konrad , loc. cit.
fig. 1, d.

6 Muller and Troschel , loc. cit. p. 132, Taf. XI.
fig. 2, Taf. XII. fig. 1.

7 Tiedemann , loc. cit. Taf. VII.

8 Muller and Troschel , loc. cit. p. 132.

9 According to Valentin'1 2 s figure of the inti-
mate structure of the digestive membranes of Echi-
nus, they are lined with hepatic epithelium, like
that of the Lumbricinae, and that of the Polyps,
already mentioned (Monogr. &c. PI. VII. fig. 126,
131, 133).

$ 87, 88.

THE ECHINODERMATA.

89

CHAPTEE VI.

CIRCULATORY SYSTEM.

§87.

The vascular, sanguineous system of these animals is yet imperfectly
known. The constant confusion and imperfection of its descriptions are
probably due to the fact that it has not been carefully distinguished from
the respiratory system ; and also, as was true of the Acalcphae, because it
has been confounded with the aquiferous system, which is usually pres-
ent.(1)

From all the old and new researches upon this subject, it is evident that
all the Echinoderms have an isolated system of this kind, composed usually
of both an arterial and venous trunk, between which there is, in some spe-
cies, an organ like a heart.

§88.

In the Crinoidea, there is, at the base of the, calyx, a heart-like saccu-
lus, from which pass off vessels into the central cavity of the arms, the
cirri, and the pedicle when it is present. From its centre, another vessel
is given off for the spongy axis of the cavity of the body.01

The Asteroidae have three vascular rings, one of which is under the
skin of the back, while the other two are beneath, around the mouth.
Between these vascular rings there is a long muscular heart, which, united
to the calcareous pouch or cord, extends from the madreporal plate to the
mouth.

It is probable that the Asteroidae, which have many of these plates,
have also many calcareous cords and hearts.® From these vascular rings
numerous other vessels are sent off, some to the stomach and its appen-
dages, and the genital organs, and others to the ambulacra and their vesi-
cles.®

1 The extended, and in some respects contradict-
ory works of Tiedemann and Delle Chiaje (loc.
cit. •, see, also, Meckel , Syst. d. vergleich. Anat.
V. p. 25 5 and Sharpe y Cyclopaed. &c. II. p. 41)
have not, for reasons which may be stated, cleared
up this point. The same may be said of what
relates to the blood of these animals, for it has
been confounded in part with the ambulacral liquid
belonging to the aquiferous system. S ee Wagner,
Zur vergleich Physiol, der Blutes, 1833, p. 28.

The observations of Delle Chiaje (Memor. &c.
n. p. 345) and of Cams (Analekt zur Natur. u.
Ileilkunde, 1829, p. 132, and Lehrb. d. vergleich.
zoot. 1834, p. 673) do not give correct ideas upon
the mode and direction of the circulation of these
animals ; for it is evident that they did not see it,
but only the vibratile phenomena of the aquiferous
system.

1 The vascular system of Comatula and Pen-
tacrinus has become known through Heusinger
(Zeitsch. f. organisch. Physik. III. 1828, p. 373,
Taf. X. XI.) and Muller (Abhandl. d.Berl. Akad.
1841, p. 198, 236, Taf. V.). The membranous canal,

8*

situated beneath the nervous branches of the arm,
and directly above the calcareous articulations, and
the passage of which through the arm into the
calyx Muller (loc. cit. p. 233) has not been able
to clearly make out, is probably a blood-vessel. It
is yet unknown how the blood of these vessels is
distributed to the organs.

2 As in Echinaster Solaris , and Ophidiaster
multiforis ; see Muller and TroscheL loc. cit.
p. 134.

3 According to Tiedemann (loc. cit. p. 49, Taf.
Till.), the lower extremity of the heart of Astro-
pecten aurantiacus opens into the vascular ring
which surrounds the mouth. This last sends arte-
rial branches to the stomach, the coeca, and the
genital organs •, the superior extremity of the
heart communicates in like manner with another
vascular ring upon the back, and which receives the
veins of the organs just mentioned. From a third
and reddish vascular ring, situated directly under
the skin of the mouth, Tiedemann has seen pass
into each ray a vessel placed superficially in the
furrow of the ambulacra, but he did not ascertain

90

THE ECHINODERMATA.

In the Echinidae, the heart is long,<4) and attached to the oesophagus.

In Echinus, it has several saccular enlargements, and internally has a
cavernous aspect, due to numerous irregularly arranged septa. At each
of its extremities there are two vascular rings. The two below are situated
on the top of the lantern and surround the oesophagus, while the two
above surround the anus ; all belong probably to the arterial and venous
systems. One of these last sends off five branches to the genital organs,
while the other receives one of the two trunks which pass along the whole
length of the intestinal canal. Two longitudinal vessels, which send off
branches right and left, pass between each of the five pairs of ambulacral
organs. These are, probably, a branchial artery and vein.®

In the Holothurinae, the vascular system, which is without a heart, is
very distinct. An aortal trunk arises from the vascular ring, which sur-
rounds the oesophagus, and ramifies upon the intestine and the genital
organs. By a reunion of these ramifications, a second trunk like a vena
cava, is formed. This divides into two arteries, which ramify upon the
branchiae, and from which arise two branchial veins, which return to the
aorta.® With the Sipunculidae, and Echiuridae, there is a main vascular
trunk, which, after sending off laterally small branches, passes along the
ventral median line, above the digestive canal.®

its relations with the rest of the vascular system.
Moreover, he has taken for an isolated, special
sanguineous system belonging to the ambulacra,
the aquiferous system, which communicates directly
with the ambulacra, and which forms a third ring,
situated between the two sanguineous ones of the
mouth.

VolkmanrCs description (Isis 1837, p. 513) is
wholly different. According to him, the vascular
trunks of the superficial ring, and which are
located in the furrows of the arms of Asteracan-
thion violaceus , send off laterally ambulacral
branches 5 the oral ring, situated more deeply,
sends off branches, which, passing through the
cavity of the body, go to the rays and ambulacra,
and freely communicate with the cavity of
these last. This same ring has also an anas-
tomotic connection with that of the back. Accord-
ing to this, the circulation occurs, he thinks, in the
following manner : The heart sends the blood into
the superficial oral ring *, thence it passes by the
vessels in the furrows of the arms into the cavity
of the ambulacra ; these last, acting as venous
hearts, send it, by the vessels in the interior of the
rays, to the second oral ring, from which it passes
to the third and dorsal ring, and thence to the
heart.

It is evident that Volfcmann has taken a part
of the aquiferous system for that of the sanguineous
one j and it is probable that he did not observe the
second oral ring. No correct idea can be formed
of the distribution of the arteries and veins of the
Asteroidae, or of their vascular system in general,
except by carefully separating it from the aquifer-
ous system, and considering the fact that the blood-
vessels do not open into the ambulacral vesicles,
but probably are spread as a capillary net-work
upon their walls.

4 The heart of Echinus , which is accurately
described by Valentin (Monogr. &c. p. 92, PI.

*[§88, note G.] See, for the vasoular system
of the Holothurio'idea, Muller (Arch. 1850, p.
229), who has carefully studied it with the larger
Synaptinae. lie confirms Tiedemann's observa-

VIII.), is attached to the oesophagus by a kind of
mesentery.

5 These details are supported by Valentin (loc.
cit. p. 93), who has already added much to the
labors of Tiedemann and belle Chiaje upon the
sanguineous system of Echinus , although, like his
predecessors, he has been deceived as to its con-
nections.

The received opinions upon the circulation of
these Echinoderms are, therefore, hypothetical. The
nature of the five glandular organs, which Val-
entin has seen communicate with one of the two
vascular rings situated upon the lantern, is very
problematical (Monogr. &c. p. 95, PI. VII. fig.
119, i. 120).

6 See Tiedemann , loc. cit. p. 15. The sanguine-

ous system of Synapta Duvernaea , as described
by Quatrefages (loc. cit. p. 58), corresponds,
properly, to the aquiferous system of Holothuria ,
which Tiedemann also has taken for a special
sanguineous system of the skin and ambulacra.
Hereafter we shall notice further both of these sys-
tems.* /

7 For the sanguineous vascular system of Sipun-
culus , and Echiurus , see Grube and Krolin (Mul-
ler's Arch. 1837, p. 248 *, 1839, p. 350), also
Forbes and Goodsir (Froriep's neue Not. No.
392, loc. cit.). The vascular trunk embraces tlkere
the nerve so closely, that care is necessary not to
overlook one, or confound both together.

Quatrefages has found in the anterior part of
the body of Echiurus Gaertneri three heart-
shaped swellings of the blood system, namely, a
ventral heart upon the ventral vessel, a dorsal
heart upon the dorsal vessel, and a mesenteric
heart situated beneath the digestive tube. This
last communicates with the ventral heart by a
fiexuous vascular canal, and with the dorsal vessel
by a small vascular ring 5 see Ann. d. Sc. Nat. loc.
cit. p. 324, PI. VI. fig. 4.

tion above quoted as to the general distribution of
the vessels, and especially as to the presence of a
splanchnic system, which, as is well known, Qua-
trefages has supposed to be wanting. — Ed.

§§ 89, 90.

THE ECHINODERMATA.

91

CHAPTER VII.

^RESPIRATORY SYSTEM.

§89.

The respiration of the Echinoclerms is performed in various ways. These
are : 1. By exclusively respiratory branchiae. 2. By organs serving
at the same time other functions. 3. By means of water passing
through the openings of the skin into the cavity of the body, and aerating
the blood through the capillary vessels of the viscera.

With the Asteroidea, Synaptinae, Sipunculidae and Echiuridae, every
individual has always two of these modes of respiration, and sometimes
all three, as with the Echinidae and Holotkurinae.

§ 90.

I. Organs which are exclusively respiratory are found in the Echi-
nidae, Holothurinae, and Echiuridae. They consist of external branchiae
in the first, and internal in the last two.

The external branchiae of the Echinidae are situated upon the soft
membrane of the mouth, being formed of five pairs of arborescent, hollow
lobules.® They are contractile, but cannot be retracted within the body.
They are covered both internally and externally with ciliated epithelium.

The cavity of each communicates with that of the body by a large ori-
fice situated on the internal surface of the oral membrane.® By this
means they are bathed with water upon both of their surfaces. Their
walls contain a coarsely reticulated calcareous skeleton,® and without
doubt, also a capillary net-work belonging to the branchial vessels.

The internal branchiae of the Holothurinae arise as two tubes from the
cloaca of the intestinal canal, and send off, through the whole cavity of
the body, numerous coecal branches.® In Holothuria tubulosa , one of
these tubes is closely connected with the turns of the intestine, while the
other is attached to the inner .walls of the body. With the first, espe-
cially, may be perceived the ramifications of the branchial vessels. They
are also covered with ciliated epithelium, and their contractile and expan-

1 The ramified organs of the Echinidae, already
known by Tiedemann (loc. cit. p 78, Taf. X. fig.
5, d. d.) and Delle Chiaje (loc. cit. EL p. 338),
have been more exactly described by Valentin
(Monogr. &c. p. 82, PI. IV. fig. 57 5 PI. VIII. fig.
42), and by Erdl {Wiegmann's Arch. 1842, I.
p. 59, Taf. II. fig. 12, 13).

2 Valentin , loc. cit. PI. VII. fig. 135, 1.

3 Valentin , loc. cit. fig. 143 5 and Erdl. loc. cit.
fig. 13.*

4 The branchiae of Holothuria tubulosa have

* [ § 90, note 3.] See, in this connection, Muller
(Arch. 1850, p. 122), who has confirmed Valen-

been very well described by Tiedemann (loc. cit.
p. 11, Taf. II. or Wagner Icon. zoot. Tab.
XXXII. fig. 9), and by Delle Chiaje (loc. cit.
Tav. VIII. IX.). See also Atlas Zool. du Voyage
de V Astrolabe. Zoophytes, PI. VII. fig. 2, 9, p.
{Holothuria ananas) and PI. VII. fig. 3, e ( Clad -
olabes spinosus). Pentacta doliolum has simi-
lar organs. According to Cuvier (Anat. Comp.
VII. 1840, p. 536) there is only a single branchia
in the other remaining Holothurinae.

tin's observations as to the structure of the exter-
nal gills. — Ed.

92 THE ECHINODERMATA. §§ 91, 92.

sive power, united with the action of the cloaca, enables them to receive
into and expel from their interior the water of the sea.®

The internal branchiae of the Echiuridae consist of branchless tubes. In
Echiurus vulgaris, the two branchiae, which are very movable and open
into a kind of cloaca, have, on their exterior, infundibuliform, ciliated pro-
tuberances ; and to each of these there is internally a corresponding cili-
ated sac, capable of being inverted. The very bright-red, vascular net-
work which is spread over these branchiae, communicates with the great
ventral vessel at the posterior extremity.®

§ 91.

II. Amohg the organs which are not exclusively respiratory, are the
ambulacra of the Echinodermata pedata, and the oral tentacles of the Ho-
lothurioidea and Sipunculidae, — organs which are used also for prehension
and locomotion.

These ambulacra and tentacles have always a cavity which communicates
directly with the proper vascular, aquiferous system. Their whole interior
is covered throughout with ciliated epithelium.

This aquiferous system has, until recently, been taken by anatomists as
a special vascular one, or confounded with it. Its water serves partly to
distend the ambulacra and tentacles, as shown above (§ 77), and partly for
respiration, which is performed by the vesicles over which ramify the
branchial vessels. These vesicles are therefore like internal branchiae,
their vessels being bathed by the water of the sacs, and that of the cavity
of the body. Usually this system consists of a ring situated between
the vascular rays of the mouth, which sends canals to the oral tentacles
and to the sides of the body. These canals always pass along by the rows
of ambulacral vesicles, with which they communicate by lateral branches.

§ 92.

In the Echinodermata pedata, this aquiferous system has the following
modifications :

In the Crinoidea, and Ophiuridae, a) only traces of it have been found.

In the first, there is an apparently aquiferous canal for the tentacles,
situated directly under their furrow. This may be regarded as forming a
part of such a system. In Pentacrinus, it is simple, but in Comatula, it is
divided at several points by simple septa.®

In the Asteroidae, this system is highly developed, the central ring being
provided with pediculated and often elongated vesicles.® The main

5 There is found, but inconstantly, it would
appear, upon the trunk of the branchiae of some
Jlolothurinae particular pedunculated coeca, which
in Bohadschia marmorata have been regarded as
urinary organs by Jaeger (De Holothuriis, &c.,
Tab. III. fig. 9, g.). But they require further
investigation.*

6 Forbes and Goodsir (Froriep's neue Not.
No. 392, p. 277, fig. 12, e. — 19).

l From the figures of Delle Chiaje (loc cit. Tav.

* [ § 90, note 5.] For many new details upon
the respiratory system of the Holothurioidea, see

XXI. fig. 17) it would appear that Ophiurus has
an aquiferous system.

2 Muller , Abhandl. d. Berl. Akad. 1841, p. 234.

3 These pyriform vesicular appendages are al-
ways situated between the principal vessels of the
rays, varying both as to number and volume, and
being sometimes entirely wanting. Astropecten
bispinosus has only five ; Asteriscus verrucu-
latus , Astropecten pentacanthus , and Astera-
canthion glacialis , have ten, in pairs. In tills

Muller , Arch. 1850, p. 129-155 ( Synapta , Chir-
odota , and Molpadia). — Ed.

§ 92.

THE ECHINODERMATA.

93

trunks from this oral ring pass along the furrows of the rays close to their
external surface. The ambulacral vesicles into which their lateral
branches open, are sometimes simple, <4) or, from a kind of sulcation, have a
heart-like form.®

In the Eshinoidea, the oral ring wants the pyriform appendages,® and
its main trunks pass along the internal wall of the shell. The ambulacral
vesicles of the oral membrane are conical ; but the others are flattened,
overlap each other in a tile-like manner ,)7) and have a distinct branchial,
vascular network.®

The aqueous oral ring of the Holothurinae has hollow appendages (ten-
tacular vesicles) projecting into the cavity of the body.® It has also, in
many species, a larger, longer, and sometimes double, coecal vessel (Am-
pulla Poliana).m Opposite the tentacular vesicles, the ring sends off to
the oral tentacles, vessels which are often arborescent and comparable to
external branchiae ;ai) while, between these vesicles, arise five other vessels
which descend along the internal surface of the body. As usual, they send
off lateral branches to the generally very small ambulacral vesicles. (12)

In a few species only of the Synaptinae, the aquiferous ring has hollow
appendages. (13) From it pass off vessels both to the tentacles and to the
sides of the body. As the ambulacra are here absent, the five main trunks
do not give off lateral branches. <u> *

In the Sipunculoi'dea, the aquiferous system is least developed. As yet
there has been found only a liquid moved by vibratile cilia in the doubly-
laminated cavity of the lobulated tentacles of the Sipunculidae. With
this cavity, two vesicles of Poli communicate, thus indicating the presence
of an aquiferous system. a5)

last species they are only slightly developed *, in
Astropecten aurantiacus there are three to seven
vesicles, opening by a common duct into each of
the five angles of the aqueous vascular ring ; see
Delle Chiaje , loc. cit. II. p. 296 ; Tiedemann , loc.
cit. p. 52, Taf. VIII. ; Konrad , loc. cit. fig. 3 ; and
Meckel , Syst. d. vergleich. Anat. V. p. 32. Here
should be mentioned also the glandular corpuscles
which are attached to the aqueous vascular ring,
and which resemble in some respects the glandular
organs of the vascular sanguineous rings of Echi-
nus, pointed out by Valentin ; see Dcllc Chiaje ,
loc. cit. II. Tav. XXI. fig. 12, 14 •, Tiedemann ,
loc. cit. Taf. VIII. o. o., or IVagner , Icon. zoot.
Tab. XXXII. fig. 2, ra.

4 Ophidiaster , Aster acanthion , Luidia ; see
Muller and Troschel , loc. cit. Taf. XI. fig. 4.

5 Astropecten ; see Konrad , loc. cit. fig. 4. I
am not yet settled upon the question whether the
aquiferous system of the Asteroidae is filled by the
extremity of the ambulacra, or by the oral ring. I
have not been able to convince myself of the pres-
ence of an opening at the extremity of these first.

6 Delle Chiaje (loc. cit. Tav. XXVI.) has given
very detailed figures of the aquiferous system of
Echinus and Spatangus ; but he has confounded it
with the sanguineous vessels of the intestinal canal.

1 Valentin , Monogr. &c. PI. CXXXIV. —
CXXXVI.

8 The branchial vessels ramifying upon the flat-
tened ambulacral vesicles appear to have been seen
by Monro (Vergleichung des Baues und der Phy-
siol. der Fische, 1787, p. 91, Taf. XXXIII. fig.
13-15 ; or Cyclopmdia of Anat. and Physiol. II.
p. 35, fig. 14). Krohn (Muller's Arch. 1841, p.
5) has accurately described them. It is affirmed
that the ambulacra of Echinus can be filled with
water through an opening of the sucker at their

extremity, and that it is discharged from the aquif-
erous system through ten openings between the
teeth ; see Tiedemann , loc. cit. p. 81 ; Valentin ,
Monogr. &c. p. 84, or Repertor. f. Anat. 1843, p.
237 5 and Monro , loc. cit. p. 92.

9 Tiedemann , loc. cit. Taf. II. fig. 4, e. e. fig.
6, m., and Delle Chiaje , loc. cit. Tav. VIII. IX.

19 Tiedemann , loc. cit. Taf. II. fig. 4, a. a. fig.
6, g. ; Delle Chiaje , loc. cit. Tav. IX. fig. 6, f.
(Ho/othuria tubulosa).

11 The position of the tentacular vesicle seems
exactly adapted to enable them to force, during
their contraction, their water into the tentacles,
thus causing the prominence and development of
these last. I am yet uncertain if they are not
aided by the vesicles of Poli. With some IIolo-
thurinae, as with Cladolabes spinosus (Atlas
zool. du Voyage de l’Astrolabe. PI. VII. fig. 3, f.),
and with Pent acta doliolum according to my own
observations, the aquiferous ring has only one ve-
sicular appendage, and it would be questionable
whether this is analogous to a tentacular vesicle,
or to one of Poli.

Thyone and Cuvieria have, according to Ko-
ren (loc. cit. p. 20, 36, fig. 2, 11), only a single
large, vesiculiform appendage upon their aqueous
ring.

12 See Delle Chiaje , loc. cit. Tav. IX. fig. 6
(Ho/othuria tubulosa ) ; but here also the aquife-
rous is confounded with the sanguineous system.

13 In Chirodota Doreyana , and fusca , these
hollow tentacular vesicles are very apparent *, see
Atlas zool. du Voyage, &c., loc. cit. PI. VII. fig. 16,
PI. VIII. fig. 3.

14 Quatrefages , loc. cit. p. 58, Tl. IV. fig. 1,
PI. V. fig. 5.

15 That the tentacular membrane of the Sipun-
culidae has the function of a branchia, is indicated

94

THE ECIIINODERMATA.

§§ 93, 94,

§ 93.

III. In nearly all the Echinoclerms, as has been seen, all the viscera are
bathed with water which certainly affects their delicate blood-vessels. It
is very probable that from ciliated epithelium covering the entire cavity of
the body and the viscera this water circulates in a definite manner. It
is rejected at last through many respiratory openings, through which also
fresh water is introduced.

In the Ophiuridae, there are in each inter-radial space two or four large
openings of this kind, leading into the cavity of the Sody.(1)

In the Asteroidae, water passes freely in and out the cavity of the
body, through small contractile trachean tubes, which have been known for
a long time, and which are very numerous upon the back. They are cov-
ered within and without with ciliated epithelium, and have an opening at
their extremity.® As yet it is unknown how the cavity of the body of
the Echinoidea and Holothurioidea receives the water. Only in Synapta
Duvernaea, have there been found proper respiratory openings ; these are
four or five papillae, covered with cilia, concealed at the base of the oral
tentacles, and connecting with the cavity of the body through a narrow
canal. V In the Sipunculidae, the water is received through an opening
at the posterior end of the body.(4)^

CHAPTER VIII.

ORGANS OR SECRETION.

§ 94.

The Echinoderms appear to have special organs of secretion. In differ-
ent parts of the body there are glandular organs, the real nature of which,
however, has not yet been determined.®

by the presence of delicate and tortuous vessels,
observed by Grube {Muller's Arch. 137, p. 253)
upon that of Sipunculus nudus. The same con-
clusion might be drawn from the liquid moved by
cilia observed by myself in the interior of the ten-
tacular lobules of Phascolosoma granulatum.
Grube (. Muller's Arch. 1837, p. 251, Taf. XI. fig.
2, P.) has seen in Sipunculus nudus the two vesi-
cles of Poli, communicating with the cavity of the
tentacular membrane.

1 Muller and Troschel , loc. cit. Taf. IX. X.

2 Ehrenberg , Abhandl. d. Berl. Akad. 1835,
Taf. Tin. fig. 12, e. $ aixl Sharper) , Cyclopaedia
of Anat. &c. I. p. 615, fig. 298, C.

* [ End of § 93.] In Echinarachnius and Cly-
peaster Agassiz has observed that trachean tubes,
similar to those of the Asteroidae, perform the
function of carrying the water in and out of the
body. They are situated chiefly along the margin

3 Quatrefages, Ann. d. Sc. Nat. loc. cit, p. 64,
PI. V. fig. 7, f.

4 The manner in which the water enters into the
interior of the Echinridae is not quite clear to me
from the description of Forbes and Goodsir {Fro-
riep's neue Not. No. 392, p. 277).

• The attention has already been directed to
these glandular organs, when speaking of the parts
to which they are attached. The calcareous sac,
or stony canal as now understood, of certain Aste-
riae, can scarcely be regarded as organs of secre-
tion.

of the disc, emptying first into a circular tube, anal-
ogous to the circular tube of the Discophora, from
which extend ramifications into the main cavity of
the body $ see Compt. rend. 1847. — Ed.

§§ 95, 96.

THE ECHINODEHMATA.

95

CHAPTER IX.

ORGANS OP GENERATION.

§ 95.

Although, most Echinoderms have extraordinary jiowers of reproduc-
tion, yet this, apparently, is not for the multiplication of the individuals,
for they do not reproduce either by fissuration or by buds.

The Holothurioidea alone, perhaps, form the exception. (1) All propagate
by the sexual organs of separate male and female individuals, and her-
maphroditism is very rare.

The eggs which are usually round, are covered by a thin chorion, and
contain beside a little albumen, a variously colored vitellus with its germi-
native vesicle and dot.(2) The sperm is always milky, and the spermatic
particles which are unaffected by sea-water, are nearly always composed'1
of a round or oval, rigid body, to which is attached a delicate, very active
tail.®

§ 96.

Externally, the organs of both sexes exactly resemble each other, and
especially during the interval of procreation ; but at the sexual epoch they
often differ in color. Their situation is very varied, and they are composed of
simple or branched tubes, with proper excretory ducts. These last, however,
are sometimes wanting, and then the contents of the former escape by rup-
ture, and, falling into the cavity of the body, pass out through the respira-
tory openings.

Here, as in the Polyps and Acalephs, the copulatory organs being absent,
the water is the medium of the fecundation of the eggs, by bringing the
spermatic particles in contact with them.

1 The Holothuria , which, when captured, dis-
charge all then’ viscera through the mouth, can,
according to Daly ell (Fr or Up's neue Not. No.
331, p. 1), not only reproduce all these, but also
can divide spontaneously into two or more parts,
each of which becomes a complete individual. This
multiplication by fissuration occurs also, perhaps,
with Synapta Duvernea ; see Quatrefages, loc.
cit. p. 26.

2 See the eggs of Comatula Europaca ( Mul-
ler, AbhaneU. d. Berl. Akad. 1841, Taf. V. fig. 17),
of Aster acantkion, violaceus ( Wagner , Prodro-
mus, &c., Tab. I. fig. 3, or Carus and Otto , Erlftute-
rungstafeln, lift. V. Taf. I. fig. 1), of Echinus livi-
dus and sphaera (, Valentin Monogr. &c. fig. 167,
169), of Holothuria talmlosa ( Wagner , Icon,
zoot. Tab. XXXII. fig. 12), and of Synapta Du -
vernaea ( Quatrefages , loc. cit. PI. Y. fig. 1).

* [ § 95, note 3.] The spermatic particles of the
Echinoderms are developed, like those of the other
Radiates, in special cells, and like them also have,
I think, invariably a cercaria-form. The differ-
ences in the shape of the head of these particles

3 See, for the spermatic particles of Aster a-
canthion , Solaster . and Echinus ( IColliker ,
Beitrfige, loc. cit. fig. 1-4, and Valentin , Monogr,
&c. fig. 168), of Holothuria and Synapta
(Wagner, Icon. zoot. Tab. XXXEI. fig. 13, and
Quatrefages loc. cit. PI. Y. fig. 2). Those of sim-
ilar form have been seen in Comatula by Muller
(Monatsbericht d. Berl. Akad. 1841, p. 189, or tho
Abhandl. of the same, loc. cit. p. 235). Accord-
ing to Valentin (Repertorium, 1841, 301),

those of Spatangus violaceus have an elongated
body, pointed in front, with a very delicate hair-like
tail. Those of Ophioderma longicauda , and
Ophiothrix fragilis , according to my own obser-
vation, h£ve a round body, with an equally deli-
cate hair-like tail.*

are wide, and of zoological import. Thus it is
sometimes round (Asterias, Urastes ), sometimes
pyriform ( Echinocidaris ), and sometimes long-
conical (Mellita). — Ed.

96

THE ECHINODERMATA.

§97.

§ 97.

In the Crinoi'dea, these organs, in the form of tubes, are situated under
the soft perisoma of the pinnulae, and probably are without proper excre-
tory ducts. a)

In the Ophiuridae, they consist of lobular, pedunculated sacs, which are
suspended in pairs in the inter-radial spaces of the disc.

These ten organs are usually deeply fissured, and the lobules thus formed
appear as so many proper sacs attached to the peduncle.® These last are
sometimes subdivided also.®

Sometimes each organ, divided in its whole length into lobules, is turned
in the shape of a ram’s horn.® The peduncle of these organs is directed
towards the mouth, but it is yet uncertain whether their contents escape
this way or fall into the cavity of the body. In the first case, the pedun-
cle would be the excretory duct ;® and in the second, the eggs and sperm
would escape through the respiratory openings.®

In the Asteroidae these organs consist of varicose lobular sacs, situated
in the angles of the inter-radial spaces.® In those species which are without
*an anus, there are no proper genital openings ; <8) these openings are also
wanting in those Asteroidae which have an anus.® In these last, the sperm
and very small eggs pass into the cavity of the body, and probably have
their escape through the respiratory openings. °0>

But in some species,0® there are upon the back and near each angle of
the inter-radial spaces two small approximated plates, perforated by small
openings ( Laminae cribrosae). These are the simple openings of these
organs, which here consist of multi-ramose sacs, situated all along each side
of the inter-radial septa, to the common duct which opens through one of the
plates.

The number of these genital sacs varies widely in the different genera
of the Asteroidae. In many, a single trunk of them hangs on each side of
the inter-radial septa ;a2>.in others, there is a whole row of them;<18) and in
others still, there are two rows attached to the dorsal surface of the cavity
of the body, and extending into the rays.°1 2 3 4) 5 6

In the Echinoi'dea, these organs descend along the internal surface of

1 The development of the genital organs of
Comatula was first observed by Dujardin , who
asserts that the red vesicles situated on both sides
of the tentacular furrows secrete, during the epoch
of rut, a very beautifully red liquid (L’Instit. No.
119, p. 268, or IViegmann's Arch. 1836, II. p.
207). Thompson has seen the eggs of Comatula
escape in clusters through the openings of the pin-
nulae (Edinb. New Philos. Jour. No. XX. p. 295,
or Froriep's neue Not. No. 1057, 1836, p. 4, fig.
8) *, while, according to Muller , they escape by
rupture (Abhandl. d. Berl. Akad. 1841, p. 234, Taf.
Y. fig. 17, 18).

2 Ophioderma longicauda , and Ophiolcpis
scolopendrica ; see Rathki , ForiepKs iifeue Not.
No. 269, p. 65*, and, Neueste Schrift. d. Natur-
forsch. Gesellsch. in Danzig. III. lift. IV. 1842,
116, Taf. II. fig. 3, 4.

3 Ophiocoma nigra ; see Rathki, Danzig.
Schrift. &c. loc. cit. Taf. II. fig. 5-7.

4 Ophiothrix fragilis.

5 Rathkt, loc. cit.

6 Muller and Troschel , loc. cit. p. 133.

1 Muller and Troschel have very interesting
details upon the various arrangements of the geni-
tal organs of the Asteroidae (loc. cit. p. 132).

8 As in Astropecten and Luidia.

9 As in Ophidiaster.

10 According to Sars , the ventral surface of the
disc and arms of the female Echinaster sanguin-
olentus and Aster acanthion Mullcri have at cer-
tain times a kind of incubating cavity, in which the
eggs remain during their development. He thinks
they get there from the cavity of the body, through
particular openings upon the ventral surface of this
last *, see Wiesmann's Arch. 1844, I. p. 169, Taf.
YI. fig. 1, 2.

The genital parts of Echinaster sanguinolentus
have been described with much detail by Sars ,
Faun, littor. Norveg. p. 48.

11 Aster acanthion r likens, and Solaster pap -
posus ; see Muller and Troschel , loc. cit. Taf.
XII. fig. 2-4.

12 Echinaster , Astrogonium , Asteriscus , and
Ctenodiscus.

13 Astropecten , Oreaster , and Culcita ; see
Tiedemann , loc. cit. p. 61, Taf. VIII. L. L.

14 Archaster , Chaetaster , Luidia and Ophidi-
aster ; see Muller and TroschcL loc. cit. Taf.
XII. fig. 5.

§97.

THE ECHINODERMATA.

97

the shell, filling the empty spaces between the double rows of ambulacral
vesicles.

They consist of widely ramified, deeply interlocked coeca, having always
proper excretory ducts, which open upon the genital plates of the back of
the shell. a5) There are here always five of these organs, and the genital
plates, alternating with the ocellary ones, surround the anus.<16) In some
species of the Clypeastridae, and Spatangidae, there are, perhaps, only four
of these organs, judging from that number of the plates. °7> In the Holo-
thurinae, these organs have a very- different arrangement. They consist of
widely-branched coeca, (18> floating, as loose clusters, freely in the cavity of
the body, and opening through a single common excretory duct, situated
below the osseous circle, and between the oral tentacles.

The testicle, which is of a whitish color, consists of a cluster of cylindri-
cal sacs, branched and interlocked with each other. (19) But the ovary is
pale red, very long, branched, a little flattened, and extends even to the
posterior end of the body/201

As the only exception among these animals, the Synaptinae are her-
maphrodites. But it should be stated that we know of them only through
Synapta Duvernaea. It is said that here the testicles and ovaries are
united in one and the same organ. (21) Three or four long cylindrical sacs
float in the cavity of the body, and have an excretory duct which opens
back of the osseous circle. At the epoch of procreation, vesicular pro-
longations appear on their interior surface, in which are formed spermatic
particles. The spaces between these prolongations are filled by a pultace-
ous mass, in which appear eggs/221

In the Sipunculidae, and Echiuridae, there are only two or four simple
cylindrical contractile pouches attached to the ventral wall. It is yet
undetermined whether their contents escape by rupture, or through special
openings/231

15 The separate sexes of Echinus were first
shown by Peters ; see Muller's Arch. 1840, p.

143.

16 See Tiedemnnn , loc. cit. p. 85, Taf. X. fig. 1,
4, 8 ; and especially Valentin , Monogr. &c. p. 103,

PI. VIII.

17 With Echinanthus , Mellita , Rotu/a, Scutella
(see Agassiz. Monogr. des Scutelles), and Spa-
tangus arcuarius , and ovatus , I can count only
four genital plates, while in Encope , and Clypcas-
ter , I find five •, yet Valentin (Repertorium, 1840,
p. 301) expressly speaks of five genital organs in
Spatangus violaceus.

18 IVagner and Valentin were the first who
noticed the Sexual differences of Holothuria t.ubu-
losa ; see Froriep's neue Not. No. 249, p. 99.

19 See Wagner , Icon. zoot. Tab. XXXII. fig. 11
(. Holothuria tubulosa). I have already remarked
{§ 86), that the white cylindrical pedicellm, taken
by some zootomists as testicles {Belle Chiaje , loc.
cit. I. p. 97, Tav. VIII. fig. 1. o.), are distinct from
the genital organs, and communicate directly with
the intestinal canal.

20 See the Catalogue of the Physiol. Series, &c.,
loc. cit. IV. PI. XLIX. fig. 1. c. {Holothuria tub-
ulosa).

21 Qualrefagcs , Ann. d. Sc. Nat. loc. cit. p. 66,
PI. IV. tig. 1, q. PI. V. fig. 1.

22 This deep confusion of the organs of two sexes

is something so remarkable, that one cannot but
believe that Quatrefages has here taken the
parent sperm cells for the eggs.

23 In Sipunculus , and Phascolosoma , there is
observed on each side, a little front of the anus, a
sac attached to the side of the body (see Belle
Chiaje , loc. cit. Tav. I. fig. 5, s. s. and Grube ,
Muller's Archiv. 1837, Taf. XI. fig. 1. v°).

These have been regarded as genital organs. In
Sipunculus 7iudus , Grube has found eggs not
only in these sacs, but in the cavity of the body
also. It may, therefore, be questioned if the eggs
escape from the sacs into the cavity of the body,
whence they are expelled through an opening at its
posterior extremity, or if they are accidentally
introduced from without with the water, during
respiration. In this last case, these sacs should
have excretory ducts ; and there are, indeed, in
Sipunculus nudus , two external fossm opposite
the point of insertion of the sacs (see Belle
Chiaje , loc. cit. Tav. I. fig. 2, f.), and in which, it
is said, there are two very small openings. Ac-
cording to Forbes and Goodsir , the genital sacs
of the male Echiurus vulgaris contain a seminal
liquid, with very active spermatic particles, while
those of the female are filled with eggs ; see Fro-
riep's neue Not. loc. cit. p. 281, fig. 20, 22, 12,
f. f.*

* [§ 97, note 23.] For the sexual organs of Sipunculus , see Peters {Muller's Arch. 1850, p.

9

98

THE ECHINODERMATA.

§ 98.

§98.

The few observations hitherto made upon the embryology of the Eehino-
derms belong solely to the Asteroidae. Here, the vitellus undergoes the
usual segmentation, and then is changed into a long, cylindrical, infusorial
embryo, covered with cilia.

A few days after, four papillae are formed upon the anterior part of
the body, and by these the embryo is attached to the walls of the incubat-
ing cavity (Bruthohle). It then begins to be flattened laterally, and
upon one of these lateral surfaces, ray-like tentacles appear, while the
margin of the body forms five angles, upon the extremity of each of which
is a red pigment dot. Then the cilia upon its surface disappear, and the
young individual, deprived of its papillae and set free, moves about by its
ambulacra. (1)

1 These interesting observations of Sirs (IVieg-
mann's Arch. 1837, I. p. 401, 1841, I', p. 160, Taf.
VI. fig. 4-22) were made upon Echinaster san-
guinolentus , and Asteracanthion MxiUeri. lie
has also observed that during the development,
the point of attachment is gradually changed, until
it reaches the back *, thus supporting the view that
the madreporal plate is the relic of this last, which,
in Comatula , has been well compared by Muller
and Troschel (Syst. d. Asteriden, p. 134), to a
button, since from- it the young individuals are
attached by a pedicle, as Thomson has shown
upon (formerly) Pentacrinus Europaeus ; see
Zeitsch. f. die Organisch. Physik. 1828, p. 55, and
the Edinb, new Philos. Jour. 1836, p. 296, or Fro -
riep's neue Not. No. 1057, 1836, p. 1. The asser-
tion of Sirs (fViegminn's Arch. 1844. I. p. 176)
that the animal which he formerly called Bipin-
naria asterigera (Beskrivelser, &c., p. 37, Tab.
XV. fig. 40) is probably only a developing As-
teroid endowed with a great swimming appara-
tus, deserves to be considered. The remark of
Dalijell ( Froriep's neue Not. No. 331, p. 2) that
the young of Holothuria are of the size of bar-
ley-corns, and resemble white maggots, is not one
that affords us any data upon the development of
these animals. There remains, therefore, a vast
field open to observers concerning the development
of the Echinoderms.

Sirs (loc. cit. p. 47, Taf. VIII.) has furnished
numerous data on the development of Echinaster.
It appears, moreover, that all the Asteroidae are
not developed after this type ; for, Koren and
Danielssen (Ann. d. Sc. Nat. VII. 1847, p. 347,
PI. VII. fig. 7-9) have shown that Bipinnaria
asterigera first observed by Sars , is a young As-
teroid which moves by means of a particular

332, Taf. IV. fig. A— II), and Krohn (Ibid. 1850, p.
368, Taf. XVI.).

Peters has found that the fine whitish line de-
scribed by Grube as lying contiguous with the blood-
vessel of the intestine is an oviduct, being filled with
ova, which move along by the action of the cilia
with which it is lined. Connecting with this ovi-
duct are botryoidal appendages, situated on the
intestine, and filled with eggs •, these are the ovaries.
The eggs, when matured, escape into the general
cavity of the body, and thence are transferred out-
wardly through two brownish tubes, which open
externally, and whose internal extremity is not
closed, as has hitherto been supposed, but opens

appendage, which is very complicated, and provided
with numerous oars, — an appendage which is sub-
sequently detached, but which continues then to
execute natatory movements. There were, per-
haps, similar appendages detached from young
Asteroids that Muller and Warner found at
Helgoland, and which they have described and
figured under the name of Actinotrocha branch -
iata ; see Muller's Arch. 1846, p. 101, Taf. V.
fig. 1, 2, and 1847, p. 202, Taf. IX. fig. 1-6.

Various naturalists have noticed interesting facts
on the development of the Echinidae in endeavor-
ing to produce artificial fecundation. In the fir3t
of these experiments, by Baer, in 1845 (Bull. de.
la Classe physico-math. de l’Acad. des Sc. de St.
Petersburg, V. p. 234, Froriep's neue Not. XXXIX.
p. 36), the eggs of Echinus esculentus, and livi-
dus , thus fecundated, were transformed, after a
complete segmentation of the vitellus, into a round,
infusoria-like body, covered with cilia. Dufossd
and Derbcs (Ann. d. Sc. Nat. VII. 1847, p. 41, and
VIII. p. 80, PI. V.) followed still further, with
Echinus esculentus , the development of these
infusoria-like embryos. They gradually became
pyriform, and acquired a peduncle at their smaller
anal extremity ; while at the larger, oral end, ten-
tacles and several long calcareous spines were
developed. At the same time the digestive canal
was formed in the interior of the body.

A small marine animal, first described by Mul-
ler (Arch. 1846, p. 103, Taf. VI. fig. 2, 3, and 1847,
p. 160) under the name of P/uteus paradoxus , has
been recently found by this same naturalist to be
the young of an Ophiura. This animal swims by
means of vibratile cilia, and is supported by a
frame composed of ten diverging, calcareous pro-
longations, resembling a painter’s easel.*

into the general cavity of the body. These tubes,
or oviducts, have been regarded Hitherto as respir-
atory or secreting organs. Krohn's observations
confirm those of Peters on this point. — Ed.

* [ § 98, note 1.] The development of the Echino-
derms has been much and successfully studied of
late, and chiefly by Muller , who, by several suc-
cessive memoirs (see loc. cit.), has changed the
zoological face of this class, beside making himself
the great authority on all that relates to its embry-
ology. The writings of Agassiz and others fur-
nish also many details, but in any account I may
give I shall depend mainly on the first-mentioned
authority.

THE ECIIIN ODERMATA.

99

§ 98.

The first condition of every Echinoderm is the
same, — an oval, ciliated body, resembling an in-
fusorial animalcule, and without external organs,
or distinction of parts. This is the starting-point,
and upon it succeed variations according to the
different families. Upon this ciliated body are
developed, at one part, peduncles for its attachment
to other bodies, while the rest of the germ increases
in size, and assumes a star-fish form.

The larvae thus formed may be divided into two
groups :

1. Those of the Ophiuridae and Ecliinidae.

2. Those of the Asteroidae and Ilolothuridae.

The first are somewhat hemispherical bodies,

with one edge of their truncated side prolonged
into a single flat and wide process, which carries
the mouth and oesophagus ; while from the oppo-
site extremity project rods, of four, eight or more
in number, and which form the internal skeleton.
(See Ueb. d. Ophiurenlarven d. Adriat. Meeres.
Taf. I. II.) These larvae have a globular stomach
in their hemispherical portion, and from which pro-
ceeds a short intestine terminating in a circular
anus. They have, moreover, a ciliated fringe,
which consists of a ridge covered with large cilia,
passing above the mouth and before the arms, com-
pletely encircling the body in an oblique manner.

With the second group there is no internal cal-
careous skeleton, and they form Muller’s Auricu-
laria (of the Ilolothuridae), and Bipinnaria (of the
Asteroidae).

The first of these are concavo-convex bean-
shaped bodies, with an irregular transverse fissure
answering to the hilum of the bean, in which the
mouth is placed. The margins of this fissure are
ciliated *, the anus opens on the ventral surface.

The Bipinnaria closely resemble these last, but
they have a distinct ciliated circle in front of the
mouth *, as they increase in size, the anterior part
of their body is covered with long processes, which
vary according to different forms.

Out of these larvae, all of which have a strictly
bilateral symmetry, the more or less radiate adult
Echinoderms are developed by a process which is
a sort of internal gemmation.

The changes and variations of this metamor-
phosis I will give in Muller's own words :

“1. The change of the bilateral larva into the
Echinodei'm takes place when the larva yet re-
mains an embryo, and is universally covered with
cilia, without a ciliated fringe. A part of the body
of the larva takes on the form of the Echinoderm ;
the rest Js absorbed by the latter (a part of the
Asteroidae, Echinaster , Aster acanthion, Sars).

“ 2. The change of the bilateral larva into the
Echinoderm takes place when the larva is perfectly
organized *, that is, possesses digestive organs and
a special ciliated fringe.

“ The Echinoderm is constructed within the Plu-
teus like a picture upon its canvas or a piece of
embroidery in its frame, and then takes up into
itself the digestive organs of the larva. Hereupon,
the rest of the larva vanishes ( Ophiura , Echinus ),
or is thrown off ( Bipinnaria ).

“ 3. The larva changes twice. The first time it
passes out of the bilateral type with lateral ciliated
fringe into the radial type, and receives, instead of
the previous ciliated fringe, new locomotive larval
organs, the ciliated rings. Out of this pupa-condi-
tion, the Echinoderm is developed, without any part
being cast off ( Holothuria , some Asteroidae).

“ If we call embryonic type the condition in
which the animal leaves the egg, and when the
internal organs are not ytt developed, we have four
stages or types, — the embryonic type, the larval
type, the pupa type, and the Echinoderm type.
The animal may pass from either of the first three
forms into the Echinoderm, or may run through
them all.” See Ueber. d. Larven u. d. Metamorph.
d. Hoioth. u. Aster, p. 33. See, also, a review of
Muller's researches, by Huxley (Ann. Nat. Hist.
VIII. 1851, p. 1), and by Dareste (Ann. d. Sc.
Nat. XVII. 1852, p. 349).

These results are highly interesting in both a
zoological and a physiological point of view, and I
need only suggest their important relations to the
doctrine of “ alternation of generations.”

In this connection, it may be proper to allude to
another point. It is well known that Vogt (Na-
turgesch. d. lebend, u. uutergegang. Thiere. 1.
Liefer. 3, p. 254) has removed the Bero’id Medusae
from the Acalephae to the a Molluscoida,” re-
garding them bilateral animals. In a private
letter from Agassiz, there is a passage bearing
directly on this point. He says : “ The young
Echinoderms are structurally and morphologically
homologous with Bero'id Medusae, showing that
Beroids are genuine Radiates, and truly belong to
the class of Acalephae, and cannot be referred to
the Molluscoids. These relations will be plain by
comparing Taf. I. fig. 6, of Muller’s Larven und
d. Metamorph. d. Ophiuren und Seeigel. 1848, with
the figures of PI. VIII. of Agassiz’ Memoir on the
Bero'id Medusae, in the Mem. of the Amer. Acad,
of Arts and Sc. Vol. IV.”

For further writings on the development of the
Echinoderms, see Muller's papers, published in
his Arch. 1843, p. 113 ; 1849, p. 84, 364 ; 1851, p.
1, 272, 353 *, but these papers are all included in
his large memoirs already given. See, also, Krohn,
Beitriig. zur Entwickelungsgeschichte der Seeigle-
larven, 1849, and in Muller’s Arch. 1S51, p. 338,
344, 368 i and Desor , Muller’s Arch. 1849, p. 79.
— Ed.

BOOK FIFTH.

.HELMUT HE S.

CLASSIFICATION.

§ 99.

It is very difficult to characterize the class Helminthes, for it con-
tains animals having widely dissimilar organization. On this account, the
separation of its groups, and their distribution among the other classes of
the invertebrata, has been attempted. But such various difficulties have
arisen from this, that for the present, it is best that all these animals
should remain together. If a common character is not furnished by their
structure, it must be sought for in their manner of life; for nearly all
are parasites,® and during their whole life, or at least during some of its
periods, seek their abode and nourishment in or upon other living animals.

ORDER I. CYSTIC I.

The body is swollen in the form of a bladder, and filled with a serous
liquid. Digestive and genital organs are wanting.®

Genera : Echinococcus, Coenurus , Cysticercus, Anlhocephalus.
ORDER II. CESTODES.

The parenchymatous body is riband-like, having often incomplete trans-
verse fissurations ; often it is wholly divided transversely into rings. Di-
gestive organs are wanting. The genital organs of both sexes are com-
bined in the same individual, and generally are often repeated. Copulatory
organs are present.

Genera : Gymnorhynchus, Tetrarhynchus, Bothriocephalus, Taenia , Tri-
aenophorus , Ligula, Caryophyllaeus.

1 Anguillula is the only exception to this. some Cestodes ; from which it might be inferred

2 The head of the sexless Cystici, as to its form, that they are only the larval forms of these last,
its hook and suckers, strikingly resembles that of

THE HELMINTHES.

101

§ 99.

ORDER III TREMATODES.

The body is parenchymatous, and usually flattened. The intestinal canal,
which is often branching, has a mouth, but nearly always is without an
anus. The genital organs of both sexes are combined in the same indi-
vidual. Copulatory organs are present.

Genera : Gyrodactylus, Axine, Octobothrium, Diplozoon, Polystomum,
Aspidocotylus , Aspidogaster, Tristomum, Monostomum, Holostomum,
Gasterostomum , Pentastomum N

ORDER IV. ACANTHOCEPHALI.

The sack-like body is flattened, transversely striated, and swollen cylin-
drically by the absorption of water. Digestive organs are wanting. The
genital organs are situated in separate individuals. Copulatory organs
are present.

Genus : Echinorhynchus.

ORDER V. GORDIACEI.

The body is filiform and cylindrical. The digestive organs are without
an anus. The genital organs are situated upon separate individuals.
Copulatory organs are sometimes present.

Genera : Gordius, Mermis.

ORDER VI. NEMATODES.

The body is sack-like and cylindrical. The digestive canal has a
mouth and an anus, and passes in a straight line through the cavity of the
body. The genital organs are situated upon separate individuals. Copu-
latory organs are present.

* In this connection, and especially in reference
to the remarks made by the author under § 99, it
may be well to notice that Fan Beneden does not
regard the Linguatulae as true Helminthes, but
that they belong rather to the division of articulated
animals, — coming nearest to the Lerneae. His
reasons are the following :
u These animals, on their extrication from the
egg, ar£ provided with two pairs of articulated feet
terminated by hooks.

“ The nervous system differs from that of the
Lerneae only in having two cords which form the
ganglionic chain, separated throughout their whole
length, whilst in the Lerneae they are separated
for only half their length.

“ In both cases the males are comparatively
very small. The ovisacs of the females are equally
bulky ; but in the Lerneae which live in water
they project externally, whilst in the, Linguatulae,
which always live in a different medium, they
remain in the interior.

9*

“ Besides the ring of nerves, the sub-oesophageal
ganglion, and the cords which represent the
ganglionic chain, the Linguatulae are provided
with different ganglia representing the great sym-
pathetic. I detected four perfectly distinct ganglia
spread over the sides of the lower surface of the
oesophagus in the new species from the Mandrill.
In another species M. Blanchard detected these
ganglia and stomato-gastric nerves; but he referred
them to the system of the nerves of relation or
those of animal life, judging, at least, from the
name which he has assigned to them.

“ Another point, which, however, had not escaped
the attention of naturalists, is that the muscles
exhibit in their primitive fibres the transverse
lines which are not met with in the lower ani-
mals.”

See Bull, de '.’Acad. Royale de Belgique, 1848,
XV. No. 3. See also Blanchard , Comp. Rend.
1850, XXXI. p. 629. — Ed.

102

THE HELMINTHES.

§ 99.

Genera: Sphaerularia, Trickosoma, Trichoccphalus, Filaria, Anguillvla,
Physaloptera, Liorhynchus, Lecanocephalus, Chair acanthus, Gnalhosoma,
Ancyr acanthus, Spiroptera, Hedruris, Strongylus, Cucullanus, Oxyuris,
Ascaris.

B I B L I 0 G K. A'P II Y .

Goeze. Versuch einer Naturgeschichte der Eingeweidewiirmer. Blank-
enburg, 1782.

Zeder. Erster Nachtrag zum vorhergehenden Werke. Leipzig, 1800.

Brera. Vorlesungen iiber die vornehmsten Eingeweidewiirmer des
menschlichen lebenden Korpers. From the Italian by Weber. Leipzig,
1803.

Rudolphi. Entozoorum Historia Naturalis. Amstelaedami, 1808—10,
and Entozoorum Synopsis. Berolini, 1819.

Bremser. Ueber lebende Wiirmer im lebenden Menschen. Wien, 1819.
Translated into the French under the title: “ Traite zoologique et physio-
logique sur les Vers intestinaux de VHomme, par Bremser, traduit par
Grundler, revu et augmente de notes par De Blainville. Paris, 1824.”
To this Leblond has added a new Atlas. Paris, 1837.

Bremser. leones Ilelminthum. Viennae, 1824.

Cloquet. Anatomie des vers intestinaux Ascaride lombrico'ide et Echin-
orhynque geant. Paris, 1824.

Creplin. Observationes de Entozois. Gryphiswaldiae, 1825 ; and Novae
Observationes de Entozois. Berolini, 1829.

Mehlis' excellent remarks upon this work in the Isis, 1831, p. 68, 166.

Bojanus. Enthelminthica, in the Isis, 1821, p. 162.

Nitzsch. In Ersch's and Gruber's Encyclopaedic, articles : Acantho-
cephala, Acephalocystis, Amphistoma, Anthocephalus, Ascaris, &c.

Creplin. In the same work, articles: Distomum, Echinococcus, Echino-
rhynchus, Eingeweidewiirmer, Enthelminthologie, &c.

Belle Chiaje. Compendio di elmintografia umana. Napoli, 1833.

Leuchart. Versuch einer naturgemiissen Entheilung der llelminthen.
Heidelberg, 1827 ; and his Zoologische Bruchstiicke, lift. I. llelm.sta.dt,
1820, and lift. III. Freiburg, 1842.

Baer. Beitrage zur Kentniss der niederen Thiere, in the Nov. Act.
Acad. Leop. Carol. Vol. XIII. p. 525.

Nordmann. Micrographische Beitrage zur Naturgeschichte der wirbel-
losen Thiere. Berlin, 1832.

E. Schmalz. XXIX. Tabulae Anatomiam Entozoorum illustrantes.
Dresdae, 1831. These contain mostly copies.

C. Th. E. Sielold. Helminthologische Beitrage und Jahresberichte iiber
die Helminthen, in Wiegmann's Arch, fur Naturgeschichte.

Diesing. His excellent Monographs in the Annalen des Wiener Muse-
ums.

F. J. C. Mayer. Beitrage zur Anatomie der Entozoen. Bonn, 1841.

R. Owen. His excellent article, Entozoa, in the Cyclopaedia of Anat-
omy and Physiology.

Dujardin. Histoire naturelle des Helminthes. Paris, 1845.

§ 100.

THE HELMINTHES.

103

ADDITIONAL BIBLIOGRAPHY.

The following are among the more important contributions to the Anat-
omy of the Helminthes which have been published since the issue of the
original work. I should mention, however, that I have not had very much
access to recent German contributions in this department, from the tardi-
ness with which such matters reach this country. However, I am happy
in not being ignorant of the late publications of Siebold , who is truly at
the head of Helminthology.

Blanchard. Recherches sur l’organisation des Vers., in the Ann. d. Sc..
Nat. VII. 1847, p. 87, VIII. 1847, p. 119, 271, X. 1848, p. 321, XI.

1849, p. 106, XII. 1849, p. 1.

Van Beneden. liecherches sur l'organisatiqn et le developpement des
Linguatules (Pentastoma, Rud.), &c. in the Mem. de l’Acad. de Bruxelles,
1848 ; also, in Ann. d. Sc. Nat. 1849, XI. p. 313.

Note sur le developpement des Tetrarhynques, in the Bull, de l’Acad. de
Belgique, XVI. 1849.

Recherches sur les Vers Cestodes, in the Mem. de l’Acad. de Belgique,

1850, XXV.

Siebold. Ueber den Generationswechsel derCestoden nebst einer Revi-
sion der Gattung Tetrarhynchus, in Siebold and IV Hiker's Zeitsch. II.
1850, p. 198.

Ueber die Verwandlung des Cysticercus pisiformis in Taenia serrata
Ibid. IV. p. 400.

Ueber die Verwandlung der Echinococcus-Brut in Taenien. Ibid.
IV. 1853, p. 409.

See, also, various valuable though small contributions, in the form of
letters to Siebold , in Siebold and Kollikcr's Zeitsch. IV. p. 52, 116, 451,
454 ; as well as the references in my notes. — Ed. -

CHAPTER I.

CUTANEOUS SYSTEM.

§ 100.

The body of the Helminthes is generally surrounded by a firm skin,
which may be separated into a thin epidermis, and a pretty hard dermis.
The epidermis of the adults is never ciliated ; but not unfrequently it has
horny spines pointing backwards, which sometimes are limited to the ante-
rior part of the body, and sometimes spread over a large surface, in trans-
versely serrated rows.a> In the first case, the spines serve to attach them

I In many Nematodes, Acanthocephali, and Tre-
matodes, the epidermis is spinous like a rasp.
These spines are simple in Liorhynchus dentic-
ulatus , Lecanocephalus spinulosus (according
to Diesing , Annalen des Wiener Museums, II.
Abth. 2, 1839, Taf. XIV. fig. 14-20), Echinorhyn-
chus pyriformis , and hystrix (> Bremser , Icon.
Helmint. Tab. VII.), Distomum Lima , maculo-

sum , scabrum , ferox , and perlatum (Ibid. Tab.
X. and Nordmann , Micograph. Beitrage. lift. 1.
Taf. IX.), and Pcntastumum denticulatum (Die-
sing, loc. cit. I. Abth. 1, Taf. III. fig. 10-13).
But they are polydenticulated in C/ieiracanthus
(Diesing, loc. cit. II. lift. 2, Taf. XIV. XVI. .
XVII.). **

THE HELMINTHES.

104

§ 101.

to other animals, and therefore will be specially described with the locomo-
tive^organs.

With most of the Nematodes, the epidermis has very fine and closely
approximated transverse folds, which are but occasionally so prominent
that the body appears annulated.(2) 3 4 Sometimes, but rarely, the body is also
plicated in a longitudinal manner.® The dermis has a fibrous structure,
consisting of two fibrous layers, — one longitudinal and the other transverse,
— which cross each other at right angles ; and of two other layers, which
intersect each other more acutely.® The skin of these animals has a
great absorptive power which during life is voluntary, but which contin-
ues to a certain extent after death, so that then these worms often swell
enormously, and sometimes burst.®

§101.

Directly beneath the skin of the Cystici, and Cestodes, are found hard
corpuscles containing carbonate of lime, and which may be regarded as the
vestige of a cutaneous skeleton. But, as they are scattered here and there
more deeply in the parenchyma, they certainly may be compared to the
spicula and calcareous net-works found in the skin of many Polyps and
Echinoderms. Oval or discoid, they are usually of equal size in the same
individual. Sometimes, however, they present irregular and unequal
forms. Always colorless and transparent, and composed of concentric
layers, they refract the light like small vitreous bodies.

In Taenia , Triaenophorus, Bothriocephalus, and the young of Echino-
coccus, they are subcutaneous, and more or less scattered; but in the
wrinkled and vesicular body of Coenurus, and Cysticercus, they are so very
abundant that they form quite thick layers. They are absent in the cau-
dal vesicle of Cysticercus, but in Coenurus, and Echinococcus , they are
found in the vesicular walls beneath the delicate epithelium which lines the
interior of the body.®

2 This is so, for instance, with the anterior
extremity of Liorhynchus denticulatus , and
Strongylus annulatus , mihi (from the trachea
of the wolf).

The epidermis o? Ascaris nigrovenosa has such
long and loose folds that its body, seen laterally,
has a fringed appearance.

3 Excepting the longitudinal folds of the epider-
mis, which form lateral wings of variable form and
length at the cephalic extremity of the N ematodes,
or on both sides of the extremity of the tail of many
males of this order ( Bremser , Icon. Helminth.
Tab. IV. fig. 20-24), I have as yet found the epi-
dermis longitudinally plicated over the whole
body only with Strongylus striatus , and injlexus.

4 These different dermic layers are distinct, espe-
cially with Gordius and Mermis ; see Dujar-
din\s figure in the Ann. d. Sc. Nat. XVIII. 1842,
PI. VI. I have found this structure also in Asca-
ris my stax, microcephala , Distomum echina-
tum , Ilians , linea , and in Monostomum verru-
cosum.

In Amphistomum giganteum , Diesing (Annal.
d. Wiener Museums, I. Abth. 2, p. 239, Taf. XXII.
fig. 1, c, d), has regarded these layers as muscu-
lar. The same is true of Bojanus (Isis, 1821, p. 166,
„ Taf. II. fig. 12), and Laurer (De Amphistomo
f conico, p. 6, fig. 15).

But the structure of the skin of Echinococcus

is quite different. Here no epidermis can be
separated from the dermis or the sac of the body ;
and the whole is a thick membrane, resembling
coagulated albumen and composed of numerous
very thin layers, tightly bound together.

5 This absorbent power of the skin is particularly
prominent with the Acanthocephali. It is here
really, a vital act *, for Echinorhynchus , which
naturally absorbs only a little liquid into its con-
stantly flattened and wrinkled body, swells and
relaxes alternately when in contact with water.
This has been observed with many species by
Creplin (Nov. Observ. de Entozois. 1829, p. 44,
and in Ersch and Grube's Encyclopaedic XXX.
1838, p. 384), by Mehlis (Isis. 1831, p. 161), and
by myself. With the Nematodes it is otherwise.
These cannot voluntarily govern this absorbing
power, and when, therefore, they are put in water,
they swell to bursting and die. With the Gordia-
cei this power is purely physical, so that the dead
and dried individuals of Gordius aquaticus , when
placed in water, quickly become round again, and
perform very active hydroscopic motions.

1 These calcareous corpuscles, which are always
without an envelope and are scattered through the
whole body of these Helminthes, have been taken
by Pallas , Goeze , Zeder , and by most Helmin-
thologists until lately, for eggs, and as such were
often figured.

$ 102.

THE HELMINTHE3.

105

CHAPTER II.

MUSCULAR SYSTEM AND ORGANS OF LOCOMOTION.

§ 102.

The muscular system is well developed with the Helminthes ; its primitive
fibres are flattened, and never transversely striated. In the Cystici, and
Cestodes, the muscles are least distinct, although in Cysticercus there can
be no question as to the muscular fibres which traverse in every direction
the walls of the caudal vesicle.® Equally distinct is a subcutaneous layer
of longitudinal fibres in the rings of Bothriocephalus and Taenia.® More-
over from the great contractility of the rings, and especially those of the
cephalic portion of the Cystici and Cestodes, there must be muscular fibres
concealed in the parenchyma, but which from their tenuity escape our
observation. In the Trematodes, having also an extreme contractility, a
large portion of the parenchyma of the body is composed of a muscular
reticulated tissue, the transverse and longitudinal muscles of which embrace
the various organs in a retiform manner.® In the Acanthocephali, the
Gordiacei, and Nematodes, the general movements of the body are due to
a subcutaneous muscular layer, which surrounds the visceral cavity in a sac-
like manner. Its longitudinal and transverse muscles are quite distinct
from each other ; and their fibres, although parallel, communicate with each
other by angular anastomes, and in this way form a net-work. (4>

In most of the Nematodes, the longitudinal muscles form four, large
bands, two upon the ventral, and two upon the dorsal surface. These

In the Cestodes, this error is unnecessary, for in
the posterior portions of their body the eggs can
easily be distinguished from the corpuscles ; more-
over, these last are the most numerous about the
neck and anterior rings, — localities where the
genital organs are scarcely and sometimes not at
all developed. It may be added, also, that these
bodies dissolve in a weak acid with the escape of
gas, while the eggs of Taenia under the same cir-
cumstances remain unaffected. In the Cystici,
which are sexless, and where therefore eggs are
vainly sought for, these corpuscles, as to their
structure, chemical composition, and position, so
closely resemble those of the Cestodes, that it ap-
pears strange that they have always been taken
for eggs. Eschricht (Nov. Act. Acad. Leopold
Carol. Vol. XIX. Suppl. alter. 1841, p. 59, 103),
not having perceived that they contain carbonate
of lime, has described them as elementary gran-
ules, and thinks that they have a nutritive function
analogous to that of the blood and lymph corpus-

Gulliver (Med.-Chir. Trans. VI. London, 1841,
p. 1; see Wiesmann's Arch. 1841, II. p. 314) has
given an exact description of those of Cysticercus ,
but he also has taken them for eggs. In Taenia
Jilum , linea , serrata , and infundibuliformis ,
they are spherical or oval 5 and in the first two
species, Goeze (Versuch einer Naturgesch. d.
Eingeweidewiirmer, p. 399, Taf. XXXII. A. fig. 6,
7, 12) has taken them for eggs, and the concentric
rings of the calcareous layers for the coils of the
embryo. With those of Cysticercus cellulosae ,
and pisiform is, the discoid form prevails ; I have
often seen here four to six calcareous layers about

the nucleus ; and sometimes there are two nuclei
thus enclosed, and then the corpuscles have ex-
actly the aspect of the precious stones of Imatra.

Those of Taenia cucumerina, Bothriocephalus
solidus, and Cysticercus fasciolaris, are usually
of an oval form, sometimes irregular, and of a
variable size. Tschudi (Die Blasenwiirmer, 1837,
p. 24, Taf. II. fig. 21) has figured those of the last
species as eggs.

1 I have easily seen these muscular fibres in the
caudal vesicle of Cysticercus cellulosae, and
tenuicollis. But they are wholly absent in the
parent-vesicle of Echinococcus hominis, and vete-
rinorum. This vesicle, therefore, has probably
no spontaneous movements, whilst the embryos it
contains at certain times have distinct locomotive
organs.

2 The longitudinal fibres of the subcutaneous
muscular layer, have been observed in Bothrio-
cephalus latus, by Eschricht (loc. cit. p. 55)
and in Taenia angulata, lanceolata, nasuta, and
villosa , by myself.

3 The reticulated muscular parenchyma of the
Trematodes ( Amphistomum giganteum) has been
represented by Diesing very beautifully (Ann. d.
Wiener Museums I. Abth. 2, Taf. XXII. fig. 4-8).

4 In Ascaris lumbricoides , as in most Nema-
todes, the muscular fibres are so closely approxi-
mated that the meshes of their net-work are not
seen except by tearing asunder the muscles ; see
Bojanus, Isis 1821, Taf. III. fig. 48. The reticu-
lated form of the longitudinal muscles is very dis-
tinct in Cheiracanthus gracilis ; see Diesing ,
Annal. d. Wiener Museums, LL. lift. 2, p. 225, Taf.
XVII. fig. 1, 2.

106

THE IIELMINTHE3.

$ 103.

bands are separated by the same number of longitudinal lines, the two nar-
rowest of which are above and below ; while the others, which are large
and riband-like, are on the sides.®

In the Acanthocephali the transverse muscles are more superficial than the
longitudinal,® while in the Nematodes and Gordiacei the inverse is true.®

§103.

There are with the Helminthes a great variety of organs for tne move-
ments of the body. With the Cystici, Cestodes, and the Trematodes, there
are often sucking-cups and cavities; the first of these are more or less
alveolate, being formed of numerous layers of circular and radiated muscu-
lar fibres,® while the second are only excavations in contractile paren-
chyma of the body, and are divided into many chambers by septa, or have
very variable lobular appendages.® Many of these suctorial organs have,
— some at their bottom, others on their borders, hooks with a horny sup-
port, by which these animals can firmly attach themselves to objects.®

6 Bojanus, Isis, 1821, p. 186, Taf. III. fig. 43,
55, B. ( Ascaris lumbricoides).

6 In Acanthocephalus the transverse muscles
intercommunicate with each other by short and nar-
row anastomoses, and form a complete ring, which
surrounds the longitudinal ones like a large girdle.
See, in reference to this, Eckinorkynchus gigas.
In Eckinorkynchus gibbosus these annular mus-
cles have been found only above the swelling of the
body.

7 The transverse muscular bundles of the N ema-
todes, which are not so closely united as the longi-
tudinal ones, do not form closed rings, but produce
four segments, which are separated from each other
by the crossing over of the longitudinal muscles.
At least, this is so in Ascaris lumbricoides , Stron-
gylus gigas , and most of the species of this order.
Bojanus (Isis, 1821, p. 187, Taf. III. fig. 51, 54)
and Cloquet (Auat. des Vers intestin. p. 35, PI. II.
fig. 3) have taken these transverse muscles for
vessels 5 and Diesing has made the same mistake
with the ramified muscles of Cheiracanthus and
Ancyracanthus (Ann. d. Wiener Museums II.
Abth. 2, Taf. XVI. fig. 1, and Taf. XVIII. fig. 2).

In Ascaris infiexa , and Filaria attenuata , I
have seen the transverse muscles ramified in the
same manner. In Ascaris spiculigera they have
a peculiarity 5 their more or less long fibres pass
off from the longitudinal muscles at a right angle,
and are inserted into one or the other of the two
narrow longitudinal rays. In the Gordiacei, the
longitudinal layer is not broken by any ray of this
kind, but forms continuous tubes which have thin
walls and a satin aspect, and where the flattened
and riband-like fibres are bound together by their
faces, and at the same time anastomose with each
other.

This would at least appear to be so, judging from
the net-work with long meshes which is produced
by a little traction. I have not found the trans-
verse muscles in Gordius ; but in Mermis nigres-
cens , there is, under the longitudinal muscular
layer, a net-work like the preceding, but with very
large meshes. Dujardin appears to have observed
it, but he regarded it as connected with the eggs
of this worm (Ann. d. Sc. Nat. XVIII. 1842, PI.
VI. fig. 13).

1 The young Echinococcus , the Coenurus ,
Cysticercus, and Taenia, have usually upon the
cephalic extremity four imperforate cup-like cavi-
ties, which can serve only as suckers. It must
have been an oversight of Nitzsch ( Ersck and
Gruber's Encyclopcedie XII. 1824, p. 95), who
regarded these in Taenia as so many oral orifices

leading into the alimentary canals. It is only with
Distomum, Ampkistomum , Polystomum, and
other Trematodes, that this sucker, which is sit-
uated in front, is perforated at its bottom, and
serves also the function of mouth.

The ventral sucker of Distomum , and that
found at the posterior extremity of Ampkistom um ,
and Polystomum , as well as the numerous analo-
gous organs upon the back of Monostomum ver-
rucosum , and upon the terminal dilatation of
Aspidocotylus mutabilis (Diesing, Ann. d. Wiener
Mus. II. Abth. 2, p. 234, Taf. XV.), are all im-
perforate. That upon the posterior extremity of
Ampkistomum subclavatum , and unguicu latum,
is remarkable ; it has a small duplicate at its bot-
tom, which Diesing (loc. cit. I. Abth. 2, p. 254,
Taf. XXIV.) has erroneously regarded as the
opening of the genital organs. In Polystomum ,
six large muscles pass from the interior of the body,
and are spread upon the convex surfaces of as
many suckers, situated at the posterior extremity,
and which they properly move during the animal’s
creeping.

^ Upon the head of Bothriocephalus , Tetra-
rhynchus, and Anthocephalus , there are two to
four simple cup-like fossae , with Tristomum ,
Polystomum , and some other Trematodes, there
are two on each side of the mouth, and with Axine,
Octobothrium., and Diplozoon, there are two
which are subcervical and behind the mouth.

With Bothriocephalus tumid ulus (Bremser
Icon. Helminth. Tab. XIII. fig. 21, or Leuckart ,
Zool. Bruchstiicke. lift. I. Taf. I. fig. 4, 5), there
are four, which are divided into chambers by many
septa 5 and with Aspidogaster (Baer, Nov. Act.
Acad. Leop. Carol. Vol. XIII. pt. 2, Tab. XVIII.),
the whole ventral disc is divided by septa into quad-
rangular suctorial fossae. The head of Bothrio-
cephalus auriculatus has a singular aspect, due to
numerous partly crenulated lobes, which flank its
four suckers (Bremser, loc. cit. Taf. XIII. fig. 17,
19, and Leuckart, loc. cit. Taf. I. fig. 6-11). A
very simple structure is found upon the head of
Bothriocephalus tetrapterus , mihi (from the
intestine of the seal) 5 here the points of junction
of the fossae are prolonged into four triangular
lobes, by which the animal can adhere tightljr to
its object. Holostomum , which lives in the intes-
tines of birds and mammals, lias analogous appen-
dages around the cavity which is situated at the
anterior extremity, and which it fastens to the
intestinal villosities *, see Nitzsch, in Ersch and
Gruber's Encyclop. III. p. 399, IX. 1822, fig. 1.

3 This condition of things is found especially in

§ 103.

THE HELMINTHES.

107

The young of Echinococcus, Coenurus, Cysticercus, and many of the
Taenia, have their head armed with a circle of single or double hooks,
which were known to the oldest Helminthologists. Each hook consists of
a strongly-curved point, situated upon a round, straight pedicle, of varia-
ble length. At the point where the curve ceases, there is, upon the con-
cave side of the organ, a small conical process. When this circle of hooks
is unfolded, the points project around the anterior part of the head, whilst
the pedicles point towards the inner and their processes towards the poste-
rior portion of the body, and are buried in the parenchyma. Both are
surrounded by muscular substance. When, therefore, the muscles of the
pedicles contract, the hooks are drawn downwards and outwards, and then-
points are brought together upon their convex surface in the long axis of
the head ; but when, on the other hand, the muscles of the processes con-
tract, these last arc depressed, the pedicles are again elevated, and the
hooks project outward. With many Cestodes, this circle of hooks is situ-
ated upon a particular proboscis (rostellum), which can be retracted into a
sheath which is concealed between the four suckers of the head.14’

With A/ithocephalus, Gym.norhynchus, and Tetrarkynchus , there are
upon the head four long and completely retractile probosces, which are
armed with an extraordinary number of small, backwardly-curved hooks
which are attached by a large base to the external surface of the organ,
and are without special muscles; by these, these animals can penetrate the
most compact animal tissues. Each proboscis is a hollow muscular tube,
which can be voluntarily retracted within a sheath of the same nature, and
then the hooks, with their points directed in front, are drawn together in
its axis. The length of the sheath, which is usually enlarged at its base,
depends upon that of the proboscis. In many species of Tetrarhyuchus,
they reach far into the neck of the animal.®

The Acanthocephali have only one of these organs, and the hooks, which
are without special muscles, form rows arranged one after another. Both
the number of these rows and the form of the hooks vary in different
species. Usually their size decreases from before backwards, so that those

the suctorial apparatus of the Trematodes. In Tris-
tomum. hamatum (see Rathke , Nov. Act. Acad.
Leop. Carol. XX. 1843, p. 241, Taf XII. fig. 11),
several sharp points project from the bottom of the
sucker at the posterior extremity. With Polysto-
mum appcndiculatum ( Nordmann , Micrograph.
Beitr'age, lift. I. p. 82, Taf. Y. fig. 6, 7), the borders
4>f the six suckers at the posterior extremity are
armed with a sharp claw. The disc of Gyrodac-
tylus (Ibid. Taf. X.) has its borders provided with
six horny points, and its base is supported by two
sides of the same nature, curved like an arc.

A very complicated support, formed of horny
arches and ridges, sustains the eight suckers at the
posterior extremity of Octobot/irium sagittatum,
Merlangi , and of Diplozoon paradoxum ; an
analogous support wholly surrounds the large foot
at the end of the body of Axine ( Leiiclcart , Zool.
Bruchstiicke lift. 3, Taf. II. and Nordmann ,
Micogr. Beitr. lift. 1, Taf. VII.; also Diesing ,
Nov. Act. Acad. Leop. Carol. XVIII. pt. 1, Tab.
XVII.).

The four fossae found on each side of the mouth
of Pentastomum contain simple and double very
curved hooks, which the animal can erect at will
( Diesing , Ann. d. Wiener Mus. I. Abth. 1, Taf.
III. IV.). A remarkable exception among the
Nematodes is found with Hcdruris androphora ,

of which Nitzsch ( Ersch and Gruber's Encyclo-
pmd. VI. p. 49, IX. Taf. II. A.) has made a sep-
arate genus ; the females have a protrusive sting
in the supker situated at the posterior extremity.

1 With Echinococcus , Coenurus , and Cysti-
cercus , the number of hooks is twenty to thirty ;
and I have seen as many with Taenia scolecina ,
and infundibuliformis ; but I have found only
eighteen with Taenia angulata , ten with Taenia
setigera , and eight with Taenia lanceolata.

Taenia scolecina , crassicoUis , and Cysticer-
cus, have an equal number of large and small
hooks alternating with each other, and, at a cer-
tain point, forming a double circle.

With Taenia , and especially those which have
these organs on the proboscis, they may be partly
or even wholly detached.

Rudolphi lias regarded Taenia gracilis, angu-
lata, infundibuliformis, setigera , and stylosa, as
naturally without these organs, but I have often
found them having a complete circle.

With Taenia cucumerina , the structure is dif-
ferent ; its seven rows of hooks are in all respects
like those of Echinorhynchus.

•5 See Leblond, Ann. d. Sc. Nat. VI. 1830, PI.
XVI. fig. 5, 6, 7 ; and Goodsir, Froriep's neue
Notiz. 1841, No. 429, fig. 18 ; also Mayer , Mul-
ler's Arch. 1842, Taf. X.

I

108 THE HELMINTHES. § 104.

of the last row are only rudimentary. The sheath of the proboscis is very
muscular, and terminates behind in a caecum ; it extends across the neck of
the animal even into the cavity of the body, and its movements are aided by
some special muscles. In all the species whatever, there are three muscles
which act as retractors of the sheath and neck. Two of these arise as
delicate cords at the anterior extremity of the body from both sides of the
internal surface of the subcutaneous muscular sac ; they traverse thence
the cavity of the body obliquely, and are inserted, in Echinorhynchus acus,
angustatus, fusiformis, and proteus, upon the sides of the sheath; but in
Echhiorhynckus gigas, haeruca, polymorphus , hystrix, and strumosus, the
insertion is at its inferior extremity. Between these two muscles, and
below their points of origin, there is a third, which divides from the sub-
cutaneous muscular sac ; this is simple, riband-like, and is inserted at the
lower extremity of the sheath. In Echinorhynchus polymorphus , and pro-
teus, its form is pyramidal. In Echinorhynchus gigas, and gibbosus, two
thin muscles arise from the anterior extremity of the body, and are inserted
upon the sides of the sheath ; they serve, probably, for the protrusion of
this organ and the neck.®

There are, moreover, upon the different parts of the body of some Hel-
minthes, horny hooks and spines, which serve for their creeping about and
permanent attachment to objects.®

CHAPTER III.

NERVOUS SYSTEM.

§ 104.

The apparently quite feebly-developed nervous system of the Helminthes
is yet but very incompletely known.

Our whole knowledge is limited to that of a small obscure ganglion found
in some species, which, as it sends off several nerves, may be regarded as

6 Helminthologists are not yet agreed as to the
number and arrangement of the proboscideal mus-
cles of the Acanthocephali ; see Nitzsch , in Ersch
and Gruber's Encyclop. 1. 1818, p. 242 ; Bojanus ,
in Isis, 1821, Taf. III. fig. 34; Westrumb, De
Helminthibus Acanthocephalis 1821, p. 50 ; and
Cloquet , Anat. des Vers, intestin. p. 76, PI. VII.
Mehlis (Isis 1831, p. 82) has taken the probosci-
deal sheath for an oesophageal organ, and its two
muscles for vessels. Burow (Echinorhynchi stru-
mosi Anatome, 1836, p. 16, fig. 1, e) has fallen
into a similar error, in regarding these same mus-
cles as intestinal tubes.

7 With many Trematodes, as, for example, with
Polystomum , Octobotlirium, fyc. (see Baer, Nov.
Act. Acad. Leop. Carol. XIII. pt. 2, Tab. XXXII.
fig. 7, f. and Mayer , Beitr&ge, &c., Taf. III. fig.
3, m. m. fig. 8), there are found between the suck-
ers at the posterior extremity, special hooks, and
to which, with Polystomum , I have seen proper
muscles proceed from the interior of the body.

With certain Cercariae (larvse of Distomum) one
can distinctly observe the use which they make of

a sting which projects from the back above the
oral sucker (and not from the mouth itself, as Wag-
ner has supposed, Isis. 1834, p. 131), and which,
serves to open a passage through the parenchyma
of the animals they infest. An entire group of
Distomum, as Distomum echinatum, militare ,
uncinatum ( Bremser , Icon. Helminth, Tab. X.
fig. 5), which Rudolphi has designated as Echinos-
tomata, have around their oral sucker an annular
collar, upon which are numerous straight spines
arranged in a circular manner. An armature of
this kind is found upon a Cercaria. These spines
are as easily detached as the hooks of the armed
Taeniae. With Spiroptera crassicauda, I have
found on each side of the mouth a doubly-pointed
sting pointing backwards, and behind this two
others three-pointed. A still more remarkable
form is seen in the four penniform stings, which
project behind the mouth of Ancyr acanthus
pinnatijidus (see Diesing, Ann. d. Wiener Mus.
II. Abth. 2, Taf. XIV. XVIII.). These Nematodes
undoubtedly use these instruments for piercing the
stomachal membranes of the animals they infest.

§ 104.

TIIE HELMINTHES.

109

a central nervous organ. There are, however, various other parts which
have been taken for nerves, but some of these, certainly, do not belong to
this system.

In the Cystici, no nervous system has yet been found, and the researches
made upon the Oestodes have ended equally unsatisfactory. A single
observation upon a Tetrarkyncus would lead us to think that in these last
the nervous system is situated at the cephalic extremity.

In Tetrarhynchus attenuatus, there is a small flattened swelling between
the sheaths of the four probosces, and from which pass off filaments to both
of these organs..’11

The observations upon the nervous system of the Trcmatodes are more
numerous and positive. Immediately behind the oral sucker, and upon
the sides of the oesophagus, are two nervous swellings, connected by a
transverse cord, which passes beneath this canal. Among the branches
given off in all directions from these, there are two, large and long, extend-
ing from each side of the body to its extremity, and which give off in their
course many lateral branchlets.®

In Pentastomum , the central portion of this system consists of a single
large ganglion, sub-oesophageal, and due perhaps to the fusion of two lateral
ganglia. From this, filaments pass off in every direction ; two of these
surround the oesophagus in a ring-like manner, while two others, analogues
of the two main trunks of the Trematodes, pass to the very extremity of
the body, giving off on their way, very fine filaments.3

1 Muller , not without reason, regards this organ
as the nervous system of Tetrarhynchus (Arch.
1836, p. CVI.). New observations are needed to
decide if, as Lereboullet (Institut. 1839, No. 812,
p. 118) supposes, there can be included in this sys-
tem the two longitudinal stripes, which, with Ligu-
la simplicissima , extend along both sides of the
ventral surface, and from which I, at least, have
seen pass no filaments.*

2 Our very exact knowledge of the nervous sys-
tem of Amphistomum subtriquetrum , and coni-
cum , and of Distomum hepaticum , we owe to the
researches of Bojahus (Isis 1821, p. 168, Taf. II.
fig. 14, 15, 19), of Laurer (De Amphistomo co-
nico, p. 12, fig. 21, 26), and of Mehlis (De Disto-
mate hepatico, p. 22, tig. 13).

By continuing the methods of these helmintholo-
gists, this system will undoubtedly be found in
other Trematodes. Diesing (Ann. d. Wiener Mus.
I. Abth. 2, p. 246, Taf. XXLI. fig. 9) has found in
Amphistomum. giganteum , and I have done the
same in Distomum duplicatum (which is prop-
erly only a larva of a species of this genus) the
same disposition noticed in Amphistomum coni-

cum. In Distomum holostomum , I have found
also a similar structure, except that the two oesoph-
ageal ganglia are widely separated, and united
by a very long cord-like commissure. Laurer
alone affirms to have seen enlargements upon the
principal nervous trunks of the Trematodes. But
their existence may be yet doubtful for no other
anatomist has mentioned them, and in no case have
I myself been able to see them. ^

3 Miram (Nov. Act. Acad. XVII. pt. 2, p. 632. *

Tab. XLVI. fig. 8) did not, apparently, notice in
Pentastomum taenioides the nervous ring which
surrounds the oesophagus ; although it had already
been noticed by Cuvier (Regne Anim. III. 1830,
p. 254), and by Nordmann , in a work in common
with Mehlis (Microgr. Beitr. lift. 2, p. 141). The
existence of this ring has been placed beyond a
doubt by the figures of it as found in Pentasto-
mum taenio'ides , and proboscideum , given by
Owen (Trans, of the Zool. Soc. I. p. 325, PI. XI.
fig. 13, or Cyclop. Anat. and Phys. II. p. 130, fig.

*78), and Diesing (Ann. d. Wiener Mus. I. Abth.

1, p. 13, Taf. I. H.).f

* [ § 104, note 1.] Blanchard (Ann. d. Sc. Nat.
1848, X. p. 338) appears to have distinctly made
out a ribrvous system in Taenia. With Taenia
serrata , there are directly behind the proboscis two
small medullary nuclei united by a commissure *,
from these pass off on each side a nerve which is
distributed to the lateral parts of the head, and
connects with a ganglion situated at the base
of each sucker, which sends filaments to the
muscles of this last. Posteriorly there are given
off filaments which run parallel to the intestinal
tubes. This, however, has not been confirmed by
other observers, and Agassiz has made a statement
in a private letter to me which is worthy of notice.

10

He says : u I believe the nervous system described
by Blanchard to be bands of muscular fibres which
cross each other between the fossae of the probos-
cis •. at least, this is so in the new species of Taenia
from Amia calva which was observed alive for sev-
eral hours ; and I could discover no nervous
threads, but only muscular fibres, which had ex-
actly the arrangement of Blanchard's nervous sys-
tem.” See, however, Valenciennes' report to the
Acad, des Sc. in the Comp. Rend. 1847, XXIV. p.
1034, also Blanchard's response to Dujardiny
Ibid. 1849, XXIX. p. 60.— Ed.

t [ § 104, note 3.] Blanchard has found with
Linguatula another ganglion above the cesopha-

110

THE HELMINTHES.

$ 104,

The central nervous system of the Acanthocephali is very distinct. It is
always concealed at the bottom of the sheath of the proboscis, which this
last, being never in a state of complete retraction, does not fill. It consists
of a dense mass of ganglionic, cellular globules blended together, and here
and there may be seen through the cell-membranes their nuclei and corpus-
cles. This comparatively large mass sends off nerves in every direction, but
the tenuity of these prevents their being traced, especially after they have
entered the muscular walls of the proboscideal sheath. (4)

With the Glordiacei,® and Nematodes, a nervous system has been found
with certainty only in Strongylus gigas. Here a cord arises from a swell-

ing in the head, traverses the whole
ventral line, and terminates at the
swelling. It sends off in its course
nervous system of the Sipunculidae.®

4 I have thus found the nervous system of the
Acanthocephali in Echinorhyncus gigas, angus -
tatus , haeruca , and proteus. It can be easily ob-
served by carefully pressing or tearing the probos-
cideal sheath. In thus tearing, you sometimes
completely expose the ganglionic mass with the
roots of the nerves. In no species that I have dis-
sected have I been able to find the ganglionic ring
mentioned by Henle ( Froriep's neue Not. No.
285, p. 330, and Muller's Arch. 1840, p. 318) ‘as
found about the genital orifice of Eckinorhyncus
nodulosus.

Dujardin also (Hist. Nat. d. Helm. p. 495, 491,
PI. VI I. fig. D. 4), has not observed it, but he dis-
tinctly perceived the central mass at the base of
the proboscis, and has figured and named it as un
corps glanduleux oil ganglionaire.

5 As yet no nervous system has been found in
the Gordiacei. Bert ho Id (Cber den Bau des Gor-
dius aquaticus, 1842, p. 12) has been inclined to
regard as nerves two delicate filaments which
traverse the cavity of the body of Gordius ; but,
a3 these give off no lateral branches, this opinion
cannot be admitted.*

6 Many Helminthologists have erroneously taken
for nerves the delicate projecting fines which, situ-

gus, which he regards as a brain ; these observa-
tions have since been confirmed by Van Beneden
(Ann. d. Sc. Nat. XI. 1849, p. 319), who, however,
regards this mass as belonging to the sympathetic
system. But, however viewed, an oesophageal col-
lar has been distinctly made out, thus confirming
the views of Cuvier.

In regard to the splanchnic system of nerves
with these animals, Van Beneden (loc. cit.) de-
scribes it as consisting of two ganglia lying on the
oesophagus back of the oesophageal collar, and
from which pass off two filaments, which run along
the oesophagus, and enter the collar laterally. He
thinks the two ganglia are united by a transverse

length of the body upon the median
posterior end of the body in another
lateral filaments, thus resembling the

ated directly subcutaneous and often blended with
the skin, traverse the whole length of the body of
many Nematodes, and have been called the ventral
and dorsal lines. Their lateral branches, as already
observed, are only transverse muscular bands.
Quite different from these is the longitudinal cord,
which Otto (Magaz. d. Gesellch. naturf. Freunde
zu Berlin, 7^ Jahrg. 1816, p. 225, Taf. V.) has
described and figured as belonging to the nervous
system •, a view which I am disposed to adopt, in
spite of Nitzsch ( Erscli and Gruber's Encyclop.
"VI. 1821, p. 45) and other Helminthologists.

In a large female Strongylus gigas , now under
my eyes, there is a simple longitudinal cord beneath
the muscular envelope, and therefore in direct con-
nection with the skin, and which extends along
the ventral surface. In its course it sends off
numberless lateral branches, which in their inti-
mate structure are quite different from the trans-
verse muscular bands. But neither here nor upon
the nerves of other worms have I ever seen the
enlargements spoken of by Otto. Grant's figure
of a double nervous filament traversing the body
of Ascaris is probably imaginary j see Outlines of
Comp. Anat. p. 186, fig. 82, A.

commissure. Further behind is another and larger
ganglion on each side, and from which pass off
filaments to the digestive cavity. See also my note
under § 99. — Ed.

* [ § 104, note 5.] This view of Berthold is sup-
ported also by Blanchard (Ann. d. Sc. Nat. 1849,
XII. p. 6), who affirms that he has observed on
both sides of the body a double longitudinal cord,
which is usually very distinct. This, examined
microscopically, appeared to be composed like the
nerves of the other Ilelminthes. Blanchard , how-
ever, did not succeed in tracing these cords to any
cephalic centres. Nothing of special value, there-
fore, is known on this subject. — Ed.

§$ 105, 106.

THE HELMINTHES.

Ill

CHAPTER IY.

ORGANS OF SENSE.

§ 105.

The sense of touch is probably the only one well developed with the Hel-
minthes. The granulations, warts, papillae, filaments, and retractile lobes,
found upon the head of some species, (,) are, without doubt, the organs of
this function. The red and black points upon the back of many, both adults
and larvae, and which have been regarded by some naturalists as organs of
vision, appear to be only pigmentary spots ; for they contain nothing like a
light-refracting body.®

CHAPTER V.

DIGESTIVE APPARATUS.

§ 106.

The digestive organs with the Helminthes have a variable degree of
development in the different orders.

In the Cystici, Cestodes, and Acanthocephali, neither mouth nor alimentary
canal is perceived. In the first two orders, there is, however, a system of
vessels which may be regarded as a digestive apparatus ; but these are
designed for circulation, rather than for digestion, since their walls are com-
plete throughout and have no openings, as has erroneously been supposed,
which communicate with the suckers of the head ; and their contained nutri-
tive material is received by them through the skin in an endosmotic manner.®

1 These tactile granulations are found with many
species of Ascaris , as, for instance, in Ascaris
osculala , between the large oral collars ; in Physa-
loptera alata , they surround the oral extremity of
the body as a single row 5 but they form a double
one in Ascaris trunculata. With Distnmum
laureatnm , and nodulosvm , they are found upon
the borders of the oral sucker. With Holostomum
excavatum , and podomorphum, there are two re-
tractile lfibules protruding from the sides of the
mouth ; and in Holostomum alatum, these have
antenna-like filaments •, see Nitzsch' s figures of
Holostomum, in Ersch and Gruber's Encyclop.
III. p. 399, IX.

2 These dark pigment-dots upon the infusori-
form embryos of many Trematodes when they es-
cape from the egg, and of which there is only one
upon the neck of Distomum nodulosum , and Ilians,
and two upon Monostomum mutabile, have been
taken for eyes by Nordmann (Microgr. Beitr. lift.
2, p. 139), and formerly by myself also (Wies-
mann's Arch. 1835, I. p. 69, Taf. I. fig. 3, 4, 5).
Three of these dots have been observed upon a
larva of a Monostomum which Nitzsch (Beitr.

zur. Infusorienkunde, p. 29, Taf. I.) has described
in Cercaria ephemera ; I have seen only two
upon the back of many cercarian larvae. Of this
same nature are the two red dots of Scolcx poly-
morphus ( Muller , Zool. Danica. Tab. LVIII. fig.
16, 17), as also the brown ones upon the neck of
Gyrodactylus auriculatus (Nordmann Microgr.
Beitr. lift. I. p. 108, Taf. X. fig. 4). Finally may
be mentioned Amphistomum subclavatum. which
has two large oval black dots upon its neck. These
pigment-cells are physiologically, without doubt,
simply colored spots, which in Polystomum inte-
qerrim um are highly developed, forming a widely-
spread subcutaneous net-work. Sometimes, and
especially in the various Cercariae, and in many in-
dividuals of Amphistomum subclavatum , these
dots have a very effaced aspect ; this is probably
due to a dissolution of the walls of the cells, — the
pigment-granules being then scattered through the
skin.

1 It has already been observed that the four
suckers of Taenia, regarded by Nitzsch as oral
orifices, are imperforate at their bottom. Oiven
(Cyclop. Anat. &c. II. p. 131) has fallen into c.

112 THE IIELMIjSTTHES. § 107.

The food enters the cavity of the body of Echinorhyncus probably in the
same manner, for their skin has great power of absorption.®

The Acanthocephali have this peculiarity, that between the skin and the
muscular walls of the cavity of the body there is a thin layer of finely-
granulated parenchyma, often of an orange or yellow color, which is traversed
by longitudinal and transverse canals.

These canals, having no proper walls, form a continued vascular system,
and contain a liquid filled with granules and vesicles. As this system is
completely closed, and cannot therefore receive nutritive substances from
without, it must be regarded as nutritive or circulatory, and not digestive,
as it has been by many naturalists.

§ 107.

In the other groups of the Helminthes the digestive organs are pretty
generally well developed.

The Trematodes have a mouth situated usually upon the border of the
cephalic extremity, and where there is a sucker occupying its bottom. From
this there passes along the middle line of the neck a thin-walled oesophagus,
which is often of an S-like form. Directly behind the mouth or oral sucker,
but sometimes a short distance removed from it, the oesophagus is surrounded
by a round or oval muscular pharynx.® From the extremity of this pass
off, usually, two blind intestinal tubes, which, passing along both sides of
the body, extend generally to its posterior extremity.® The other forms
of the digestive canal are as follows : in Monostomum mutabile,iS) and jla-
vum, the two intestinal tubes, instead of ending coecally, form the arc of a
circle ; <4) in Aspidogaster , a simple and uniform intestine succeeds upon the
pharynx, and ends in a coecum at the posterior extremity of the body ;<5>
in Gasterostomum Jimbriatum, this canal is very short, and terminates in
the same way, but there is a mouth in the middle of the ventral surface ;
in Bucephalus polymorphus , (G) the structure is similar; and in Pentastomum,

similar error in regarding these organs as mouths,
not only in Taenia and Cysticercus , but also in
Bothriocephalus. I have been unable to find a
mouth upon the cephalic extremity of the Cestodes,
as has Mehlis (Isis, 1831, p. 131), or upon that of
Taenia solium , as has Owen (Lect. on the Comp.
Anat. kc. p. 48, fig. 21, a.). The fossa sometimes
found upon this last, is due to the retraction of the
circle of hooks, or of the proboscis, within the
sheath.

2 Most Helminthologists admit that Echinorhyn-
chus receives its food through a small orifice at
the extremity of the proboscis, the sheath of the
last aiding in suction and deglutition. I have been
unable to convince myself of the existence of this
orifice, and never have found food in the cavity of
the sheath. On the other hand, I have often, like
Creplin and Mehlis , seen Echinorhynchus re-
ceive and reject liquids through the skin.

1 With Distomum globiporum , the pharynx is
somewhat removed from the oral sucker ; see Bur -
meister , in Wiegmann’s Arch. 1835, II. fig. Taf.
1, 3. In Distomum echinatum , militare and
allied species, the oesophagus is usually very
long. But in Distomum oxycephalum , it is very
short *, and in Distomum appendiculatum , it is
entirely wanting, and consequently the intestinal
bifurcation is directly behind the pharynx.

2 In Monostomum , Amphistomum , Holosto -

mum , Distomum , and Polystomum ;, the intestinal
bifurcation extends to the posterior extremity of
the body. With Distomum chilostomum , and
many other species of this genus living in the Neu-
roptera, the whole intestine is reduced to two short
right and left coeca, which are given off from the
end of the oesophagus.

3 Creplin , Nov. Observ. de Entozoi's, fig. 10, 11.

4 This arrangement has been also, but errone-
ously, assigned to Distomum ter eticolle ; see
Wagner , Lehrbuch der vergleichenden Anat. 1834,
p. 75, and Creplin , in Ersch and Gruber’s Ency-
clop. XXIX. 1837, p. 314.

This error is probably due to the inaccurate copy-
ing of figures *, see Ann. d. Sc. Nat. II. 1824, p.
493, PI. XXIII. fig. 4, 5 *, and Schmalz , Tabulae
Anat. Entozoorum, Tab. VIII. fig. 3, 3. By refer-
ring to the original figure in the Memoir of Jurine
(M<jm. de la Soc. de Phys. et d’Hist. Nat. de
Geneve, II. pt. 1, 1823, p. 149, fig. 4, 5), from which
these have been copied, there is found no trace of
a closed, arcuate intestinal canal behind. More-
over, Jurine expressly says that he has seen the
intestinal tubes of Distomum terreticolle , as coeca.

5 Baer , in Nov. Act. Acad. &c. XIII. pt. 1, p.
536, Taf. XXVIII. ; also Diesing, Med. Jahrbuch.
d.k. k. bsterreichischen Staates. XVI. 1834, p.423,
fig. 8-11.

6 Bucephalus polymorphus is probably a larval

§ 108.

THE HELMINTHES.

113

this canal is simple, straight, and ends posteriorly in an anus.® In many
Trematodes, the intestinal tubes have in all their course simple or ramified
caeca, and in some, these caeca are so fully developed that the intestinal
canal appears to fill the whole body.® The intestinal walls here are very
thin, but this does not prevent peristaltic and anti-peristaltic movements, by
which their contents move backwards and forwards, and are often rejected
through the mouth.®

§ 108.

In the Nematodes, and Gordiacei, the intestinal canal passes straight from
the mouth which is at the anterior extremity, through the cavity of the
body to the anus, which, in the first, opens front of the caudal extremity. a)
In very many Nematodes, the mouth has nodosities and swellings, but it is
seldom that its cavity has horny, tooth-lilce processes.®

From the mouth extends a long and very muscular oesophagus, which is
usually dilated claviform at its lower extremity. When the oesophagus is
very long, it has one or more constrictions.® It is nearly always composed
of three longitudinal muscles which are united by longitudinal seams. The
triangular cavity circumscribed by these muscles is lined by a very firm
epithelium, which is sometimes horny, and in some species so thickly set in
the clavate dilatation that it resembles a masticatory apparatus.® The
intestine consists of a straight tube, with thin walls and without dilata-

Gasterostomum ; and the species above men-
tioned I have discovered in the intestinal canal of
Perea Jhiviatilis , and Lucioperca.

7 See Miram , Owen , and Diesing, loc. cit. The
opening at the posterior extremity of many Trema-
todes, and by many Helminthologists taken for an
anus, belongs to a special secretory organ, which
will be mentioned hereafter.

8 In many species allied to Monostomum trigo
nocephalum, the two intestinal tubes have simple
caeca upon both sides of their entire length. In
Octnbothrium lanceolatum, the structure is the
same ■, see Mayer , Beitr. p. 21, Taf. III. fig. 3.
These lateral caeca are more or less ramified in Oc-
tobothrium palmatum, sagittatum, Merlangi ,
Polystomum app endiculatum, and Tristomum
elongatum ( Leuckart , Zool. Bruchstiicke, lift. 3,
p. 26, 54, Taf. I. fig. 4, c. b. Taf. II. fig. 5, d. •,
Nordmann , Microgr. Beitr. lift. 1, p. 79, 81, Taf.
VII. fig. 2, Taf. V. fig. 6 ; and Baer, Nov. Act.
Acad. Leop. XIII. pt. 1, p. 665, Taf. XXXII. fig.
2). With Distomum hepaticum, these ramifica-
tions are very fully developed ; see Mehlis, Observ.
de Listomate, fig. 1, 2, 7, 8. In the very remark-
able genus Diplozoon , the digestive canal consists
of a single tube which traverses the whole body
upon the median line, and sends off laterally
ramified caeca, while at the point of junction of
the two -bodies of the animal it dilates into a stom-
achal cavity $ see Nordmann, loc. cit. lift. 1,
p. 67, Taf. V. fig. 2. The blackish ramifications
of Polystomum integerrimurn , and which have
been regarded by Baer (Nov. Act. Acad. Leop.
loc. cit. p. 682, Taf. XXXII. fig. 7, 8) and other
authors as a digestive canal, belong to the subcu-
taneous pigmentary net-work already mentioned.

9 The digestive canal of Trematodes is usually
partly filled with blood which they have absorbed,
and partly with brown or yellowish chyme •, it is
therefore evident how, from the thinness of its
walls, it would, when empty, entirely escape the
observation.

1 Among the Nematodes, and Gordiacei, there

are, moreover, species which have very rudiment-
ary digestive organs. In Sphaerularia bombi,
there is neither mouth nor anus, and in the place
of the intestinal canal there is a row of long sacs
clinging together, and around which the genital or-
gans are coiled ( Wiegmann's Arch. 1838, I. p.
305). In Filaria rigida , living in the intestines
of Aphodius Jimetarius, I have found no digest-
ive canal whatever (Muller's Arch. 1836, p. 33).
In the various species of Mermis, there is a dis-
tinct mouth, oesophagus and intestine, but this last
ends in a caecum. I have been unable as yet to
positively determine a mouth with Gordius aqua-
ticus ; the anus is certainly wanting, and it might
be questioned if the two tubes which traverse the
body should be regarded as an intestine ; see
Wiegmanri's Arch. 1843, II. p. 305.

2 With Strongylus armatus, hypostomus, den-
tatus, and tetracanthus, the entrance of the mouth
is provided with a circle of horny teeth, which are
moved by special muscles -, see Mehlis, Isis. 1831,
p. 78, Taf. II. fig. 5, 6. With Spiroptera stron-
gylina, I have seen the entire internal surface of
the mouth provided with a spiral, horny swelling.
In Cucullanus , there is a very complicated appa-
ratus for opening and closing the mouth, composed
of solid, horny pieces.

3 With Anguillula fluviatilis, Oxyuris vermi-
cularis , Ascaris acuminata, brcvicaudata, dac-
tyluris , oxyura, and vesicularis, the oesophagus
has this enlargement. But it is divided into two
portions by a prominent constriction with Cucul-
lanus elegans, Physaloptera alata, Spiroptera
anthuris , europtera , obvclata , and crassican-
da. In Trichocephalus, it is very long, and has
behind very many constrictions, which are succes-
sive at short intervals •, see Mayer, Beitr. &c. Taf.
I. II. With Trichosoma falconum, it is equally
long and divided into many sections, which give it
an articulated aspect.

4 By many Helminthologists this tube has been
called oesophagus , and its dilatation stomachus.

114

THE HELMINTHES.

§ 109.

tions, and which terminates in a short muscular rectum. The proper intes-
tine is of a brown, greenish, or dirty yellow color, which is due to its walls
being formed of compact cells filled with colored granules. The loose and
cellular walls, having very feeble peristaltic movements, are surrounded
externally by a kind of deuse peritoneum, and lined internally by a very
fine epithelium.® In some species of Ascaris, the intestine is lengthened
into a caecum at its junction with the oesophagus.®

§ 109.

There are observed, here and there, only traces of appendant organs of
the digestive canal.

In many Trematodes, there are upon each side of the neck, two more or
less developed cords or canals, of a cellular aspect, and of a pale yellow
color by direct light. They pass towards the mouth, open perhaps into its
cavity, and have a function, probably, like that of salivary organs .(1> In
many Nematodes, two or four caeca extend from the cephalic extremity
along the oesophagus, and as they open distinctly into the oral cavity, it is,
therefore,- the more probable that they should be regarded as salivary
organs.® The same signification should be given to the coecal appendage
found in many species of Ascaris, which extends from the constriction of
the oesophagus to the beginning of the intestine.®

Hepatic organs have been found nowhere but in the Nematodes; but it
may be that the granular cells in the- thick walls of the intestinal canal,
take their place.

0 This epithelium has sometimes special inequali-
ties. which, with Ascaris osculata , and spiculige-
ra , form a regular zig-zag series, resembling the
valves of the intestinal mucous membrane of some
vertebrates. With Ascaris aucta, they have the
form of long, sharp villosities.

G This eaecal appendage, accompanied usually
with a constriction of the posterior end of the
oesophagus, was first observed by Mehlis (Isis.
1831, p. 91, Taf. II. fig. 16, 17, 18). It is found
with many Ascaris , but its length is very variable.
In Ascaris hcterura , semiteres , and ensicaudata ,
it is very short, and protrudes scarcely beyond the
oesophageal constriction ; while in Ascaris depress
sa, aucta, angulata, and mucronata , it reaches to
the middle of the oesophagus, and in Ascaris spi-
culigcras osculata , and the species described as
Filaria piscium, it extends nearly to the cephalic
extremity.*

1 These glandular-like organs are often very
distinct in* the cercarian larvae of the Trematodes,
and in many adults of Monostomum , and Disto-
mum ; see Wiesmann's Arch. 1843, II. p. 322.

2 Mehlis (Isis, 1831, p. 81, Taf. II. fig. 6) has
observed with Strongylus armatus, an annular
vessel surrounding the mouth, which communi-

* [ § 103, note 6 ] See, for the alimentary canal
of Ascaris infecta , Leidy (A Flora and Fauna
within living animals, Smithsonian Contrib. V. Art.
2, p. 43, PI. VI. fig. 1-7). He divides it into a
strongly muscular gizzard, a cylindroid intestine
lined with hexahedral epithelium, and a pyriform
rectum.

See also his description of that of Streptoso-
mum , Thelastomum, &c. (Ibid. p. 49). In The -

cates with it directly, and also with two cords
accompanying the oesophagus. According to him,
there is also a similar disposition with $trongylus
hypostomus, and tetracanthus.

Similar appendages, analogous to salivary or-
gans, occur, according to Owen , in the new genus
Gnathosoma , as four caeca surrounding the oeso-
phagus, and opening into the mouth ( Wies-
mann's Arch. 1838, I. p. 134). With Cheir acan-
thus, and Ancyr acanthus, there are four similar
organs, and Diesing is certainly in error in
regarding them as analogous to the ambulacral
vesicles of the Echinoderms (Ann. d. Wiener Mus.
II. Abth. 2, p. 224, 226, 223, Taf. XVII. fig. 8, 9,
Taf. XVIII. lig. 3). 1 am disposed to regard as
salivary organs, also, the two long caeca which
pass from the mouth along the oesophagus of
Strongylus strialus.

3 I have discovered a similar oesophageal ap-
pendage in a group of Ascaris known as Filaria
piscium ( Wiegmann's Arch. 1838, I. p. 309) *,
such are, Ascaris mucronata, angulata, oscu-
lata, spiculigera , aucta, anus, and labiata. It is
remarkable that with the exception o the last two*
all these have also a caecum upon the intestine.

lastomum appendiculatum, there is this pecu-
liarity, that the intestine commences by a broad,
deeply sinuate, cordiform dilatation, which rapidly
narrows to a short, cylindroid portion, and then
sends off a long, capacious, gourd-form receptacle,
or diverticulum, and afterwards proceeds back-
wards to the rectum, and in its course, in the vi-
cinity of the generative aperture, performs a single
short convolution. — Ed.

$ 110.

THE HELMINTDES.

115

CHAPTER VI.

CIRCULATORY SYSTEM.

§ 110.

Most of these animals have a vascular system. The circulating liquid
is usually wholly colorless, and often contains vesicular or granular cor-
puscles, which are difficult to perceive from their delicacy and transparency.
The circulation is due to the general contractions of the body or of the
walls of the vessels.

In the Acanthocephali, the vessels have no proper walls, but are spread
out, as has already been said ( $ 106), in the subcutaneous parenchyma.
There are two larger, lateral canals, which pass from the neck to the caudal
extremity, sending off laterally numerous small canals, which anastomose
with each other. A similar net-work is found in the proboscis through its
whole length. (1) These two canals connect also with the lemnisci, upon
each side of the neck. These last, of which there are always two upon the
sides of the proboscis, passing from the neck to the cavity of the body, are
usually riband-like, and composed of a finely-granulated parenchyma,
which, like the cutaneous one, has a system of vascular canals. (2)

In most species of Echinorhynchns, this system consists of a main canal
upon the border of the lemniscus, from which are sent off' inwardly, nu-
merous small branches. These last form the net-work which fills the paren-
chyma of the proboscis.®

In many,(4> the lemnisci are surrounded by muscular fibres, which, con-
verging to the posterior extremity of these organs, form two short muscles,
which, in their turn, are blended with those passing obliquely to the pro-
boscideal sheath. The point of junction is at a short distance from the
place where they are detached from the subcutaneous muscular layer.
Each lemniscus is constricted into a narrow neck at its base, which passes
into the skin at the base of the proboscis. The junction of the cutaneous
with the lemniscian vascular system occurs at this point, as is indicated by
the contained liquid passing backwards and forwards between the two from

1 This vascular system, taken by many Hel-
minthologists for a digestive canal, has been fig-
ured by IVestrumb (De Helminth Acanthocephalis
Tab. II. fig. 10, HI. fig. 10, 12, 21), and Burow
(Echinorhynchi strumosi Anat. 1836, fig. 1, 8).
The movements of the nutritive liquid may be
distinctly seen by placing these animals alive and
undilated as natural under the microscope. One
will then be quickly convinced that the circulation
is due to the general movements of the body. If
Echinorliynchus is placed in much water, the
absorption distends not only., the body, but the
canals of the vascular system are so filled that the
subcutaneous parenchyma is swollen, and the
skin is raised here and there into vesicles.

2 With Echinorhynckus angustatus, acus ,
fusiformis, proteus, and polymorphus, the two
lemnisci have a riband-like form. In Echino-
rlnynchus gigas , they are very long j and in Echi-

norhynchus claviceps , they are longer than the
body, and lie coiled in its cavity. In Echino-
rhynchus gibbosus , hystrix. and strumosus ,
they are discoid and very short.

3 Echinorliynchus angustatus , haeruca , poly -
morphus, proteus, and gibbosus. As a wide
exception, the principal canal occupies the median
line of the lemniscii, and sends off laterally small
branches, with Echinorhynchus gigas. Here
and there its course is broken by oval, voluminoun,
transparent and apparently vesicular bodies •, see
IVestrumb loc. cit. Tab. II. fig. 7. Similar bodies
in the lemnisci and subcutaneous parenchyma, are
found with Echinorhynchus claviceps ; see Mul-
ler, Zool. Danica. Tab. LXI. fig. 3. These bodies
are, moreover, regular neither as to their number
nor position, and I have not learned their nature.

4 Echinorhynchus acus , angustatus , fusifor-
mis , and proteus.

THE HELMINTHES.

116

§ 111.

the peristaltic actions of the body and the alternate retraction and pro-
traction of the proboscis.®

In the Gordiacei, and Nematodes, no vascular system has as yet been
found. Only in a group of species described as Filaria piscium, has there
been found a riband-like organ concealed in the cavity of the body, and
traversed by a net-work of canals, which resemble those of the lemnisci of
the Acanthocephali.®

§ 111.

In the Cystici, Cestodes, and Trematodes, the vascular system is well
developed. Its canals have proper walls, the contraction of which pro-
duces the circulation. In the first two orders, it consists of two pairs of
longitudinal canals, which pass along the sides of the body and head, and
intercommunicate occasionally, by transverse canals. These four vessels
open, in the head, into an annular ring which surrounds the proboscideal
sheath; there is here, therefore, a completely isolated system.® In the

Trematodes, this system consists of
the whole body; and in which are
the sides of the neck and body.®

5 Mehlis (Isis, 1831, p. 82) affirms to have seen
on the neck of Echinorhynchus gigas two small
orifices by which the lemnisci open outwards. But
I have been unable to see them in this species, or
others of this same genus. If they really exist,
they will shed light upon the doubtful functions of
these organs. From what we know of their struc-
ture, it is not improbable that they belong to the
nutritive system, and transude a liquid which
bathes and nourishes the organs in the cavity of
the body.*

6 With the Nematodes, the liquid appears to
transude through the walls of the intestine into the
cavity of the body, and there bathe, without a vas-
cular system, all the organs. The riband-like organ
found in the Filaria piscium (see Wiesmann's
Arch. 1838, 1. p. 310), and which I have also found
in Ascaris osculata , has the same vascular rami-
fications as the lemnisci of Echinorhynchus gi-
gas, and the vesicle-like bodies are not wanting
upon the course of the principal canal. Perhaps
they also transude the nutritive liquid, for I have
not found any communication between them and
the intestinal canal.

The two lateral enlargements also, which, as
already mentioned (§ 102), are extended between
the longitudinal muscles of the skin, have often
been regarded as sanguineous vessels ; but I have
observed with them neither longitudinal nor lateral
canals. t

1 These lateral vessels, regarded by some Hel-
minthologists as intestinal tubes, give off in their
course no lateral branches, except these transverse
canals. With the articulated Cestodes, these last
are always situated at the posterior extremity of
the articulations, thus giving a ladder-like aspect
to the entire vascular system. They are also
found, however, in Caryophyllaeus mutabilis ,
which is not articulated.

* [§ 110, note 5.] The observations of West-
rum b and Bur ovu on the circulatory system of the
Acanthocephali, have recently been thoroughly
verified by Blanchard, who has illustrated it with
excellent figures ; see Ann. d. Sc. Nat. 1849, XII.
p. 21, and R£gne animal, nouv. Edit. Zoophytes,
PI. XXXV. fig. 2. — Ed.

a contractile net-work spread over
two larger trunks, which pass along

Platner (Muller's Arch. 1838, p. 572, Taf.
XIII. fig. 4, 5) affirms to have seen semilunar valves
at the orifices of the transverse canals of Taenia
solium.

The four lateral cervical vessels which I have
observed not only in Taenia , but also in Bothrio-
cephalus , and Cysticercus , may be traced with
perfect distinctness in Taenia cyathiformis, and
serrata, to the vascular ring which surrounds the
proboscideal sheath. With Caryophyllaeus mu-
tabilis, and Taenia ocellata, which are without a
proboscis, this vascular ring does not exist any
more than with Bothriocephalus ,• here also the
four lateral vessels widely ramify in the head, and
form by anastomoses, a distinct net-work. Both-
riocephalus claviceps has a similar organization.
It should, moreover, be here observed that from
the contraction of its very thin walls the vascular
system will easily elude the observer.

2 The vessels of the Trematodes are remarkable
for their prominent flexures *, see Distomum cir-
rigerum , tereticolle , duplicatum, and the various
species of Diplostomum (Nordmann Microgr.
Beitr. lift. 1, Taf. II. fig. 8, IV. fig. 5, 6). One
should not confound with the sanguineous vessels,
as has often been done, the very finely-ramified
canals of the excretory organ, which will hereafter
be mentioned. Thus I think that the vascular
net-work of Distomum hepaticum described by
Bojanus (Isis, 1820, p. 305, Taf. IV.) belongs to
this excretory organ. Laurer also (de Amphis-
tomo conico. p. 10, fig. 22), has not carefully dis-
tinguished them ; and Nordmann appears to have
fallen into the same error (loc. cit.).

With Diplostomum, the vessels open each side
into a large reservoir situated at the extremity of
the body. Between these two receptacles, the
excretory organ passes to the extremity of the
body, and Nordmann has taken its orifice as

t [§ 110, note 6.] Berthold (Heber den Bau
des Wasserkalbes. &c. loc. cit.) has described a
vascular system with the Gordiacei; but Blanchard
(Ann. d. Sc. Nat. 1849, XII. p. 7) has failed to
confirm his statements after very careful research.
— Ed.

§112.

THE HELMINTHES.

117

CHAPTER VII.

RESPIRATORY SYSTEM.

§ 112.

A respiratory system has not yet been found with certainty in the
Helminthes.

The pedunculated vesicles of many Nematodes, situated under the skin,
and projecting into the cavity of the body, and which have great absorp-
tive power, have been compared to trachean pouches and branchiae ; but
their structure is so little known, that any opinion as to their function
ought to be deferred.®

A remarkable fact is the presence in some Trematodes of extremely
active vibratile lobules, situated intermittingly on the inner surface of the
walls of the vessels.® It may be questioned if these vessels have a special
function, different from that of the others. They somewhat resemble the
aquiferous system of the Polyps, Acalephs, and Echinoderms, and like it,
belong, perhaps, to the respiratory system. They differ, however, in not
having openings which communicate outwardly ; but, probably, they receive
by endosmosis, water absorbed by the skin.® But another objection to this
view, is, that in this order there has been found nothing like blood-vessels.

belonging to the nutritive vessels. The nutritive
liquid of the vascular system differs from the
coarsely-granulated excretion of the excretory
organ, by its homogeneous and colorless aspect.

It is remarkable that in Distomum tereticolle
this liquid has a reddish color, which, in the finest
capillaries has a yellowish cast ; see Wiesmann's
Arch. 1835, I. p. 59.

//. Meckel , likewise, thinks that the above-de-
scribed vascular system of the Trematodes, is in
direct communication with the secreting organ
peculiar to these Helminthes j see Muller's Arch.

1846, p. 2, Taf. I. fig. 2.*

1 Bojanus (Isis, 1821, p. 187, Taf. III. fig. 51-
55) affirms to have observed in Ascaris lumbri-
co'ides these pedunculated vesicles, which are
found also in Ascaris depressa, and Strongijlus
gigas, in connection with the lateral swellings ;
but this throws no light upon the nature of these
vesicles, for we are yet ignorant of that of these
swellings. The stigmata which he affirms (loc. cit.
p. 187, Taf. III. fig. 56) to have observed upon
these lines with Ascaris acus , are, according to
my own observations, only subcutaneous cell-like
bodies.

2 I have quite distinctly seen these vessels with
Diplozoon paradoxum, Aspidogaster conchi-
cola , Distomum echinatum , and an allied species
of this last from the intestine of Falco apivorus.

* [ § HI, note 2.] Van Beneden (Ann. d. Sc.

Nat. 1852, XVIII. p. 23) has recently expressed
doubts upon the presence of a circulatory system

I am yet uncertain if the vibratile organs found
in the neck of Distomum globiporum and nodu-
losum. ( Wiegmann's Arch. 1836, I. p. 218), and
in the parenchyma of Distomum duplicatum be-
hind the ventral sucker, are of the same nature.

Ehrenberg (JViegmann's Arch. 1835, II. p.
128) was the first who observed this ciliary move-
ment in the vessels of Diplozoon. When the
motions of these lobules are free, there is a rapid
current of the liquid, as Nordmann has remarked
(Microgr. Beitr. lift. I. p. 69). But if an animal
is compressed between two plates of glass, and
their motions thus impeded, it will be quickly seen
that these last are the cause of the circulation *, in
fact, when the lobules cease moving, the colorless,
homogeneous, and, without doubt circulatory liquid,
is no longer perceived.

3 Burin eister (Handbuch d. Naturgesch. 1837,
p. 528) compares, not without reason, this system
to the trachean system of insects, the first being
aqueous , and the second aerial respiratory organs,
thus confounding this vascular system of Helmin-
thes with the excretory organ and duct found in
most Trematodes. There may be, however, a com-
parison between these two systems, if we except
the insects with stigmata, and take those which are
aquatic and have a completely closed trachean
apparatus (see below), admitting no air from with-
out.

with the Cestodes and Trematodes, but see the
beautiful plates of Blanchard , Ann. d. Sc. Nat.
1848, X. PI. XI. — Ed.

118

THE HELMINTHE3. .

§113

CHAPTER VIII.

ORGANS OF SECRETION.

§ 113.

No organs of secretion have been found, except in the Trematodes and
Nematodes. In most of the Trematodes, there is, upon the median line of
the posterior part of the body, a contractile sac, which usually opens out-
wards/0 at the caudal extremity, and seldom at the posterior part of the
back.® This sac is single,® bifurcate,® or multiramose. In the last case,
its branches are spread usually over the whole body.® Its walls are quite
thin, and therefore, it is seen with difficulty when wholly contracted or
empty. It contains a colorless liquid filled with numerous granules or
vesicles, which, during the contractions, pass up and down, or escape
through the external opening.® This organ is sometimes so crowded with
clear, solid corpuscles, composed apparently of earthy matter, that exam-
ined by reflected light, it has a cretaceous aspect.®

In many Nematodes, there is on the ventral surface and at a variable
distance from the head, a small oblique opening surrounded by a sphincter.
In some species, two canals pass from it and run backwards on each side
of the intestinal canal ; and in others, there are also two other canals which
extend forwards in the same way. The use of the colorless and homoge-
neous secretion of these organs is yet unknown.®

1 This opening, known as the Foramen caudate
with Distomum , Holostomum, Monostomum ,
Aspidogaster , and Diplostomurn , has formerly
been compared to an anus by Nardo (Heusi ti-
ger's Zeitsch. fur organische Phys. 1827, I. p. 68),
and by Baer (Ibid. II. p. 197). Mehlis (Observ.
de Distomate,p. 16) having shown that it belonged,
in Distomum hepaticum , to a particular organ
which is ramified like a vessel, has properly re-
jected this analogy ; see Isis, 1831, p. 179. With
the larvae of Trematodes, known as Cercaria,
Bucephalus, and Distomum duplicatum, the
base of the tail is thrust into the excretory opening
of this organ, and its contents cannot escape until
the animal has lost the tail.

2 Amphistomum.

3 Monostomum faba , Distomum cirrigerum ,
Gasterostomum Jimbriatum, and Bucephalus
polymorphus.

4 Distomum chilostomum, clavigerum, lima ,
maculosum, tereticolle , variegatum , and many
species of Monostomum , — where the two closed
ends of the sac often extend to the cephalic ex-
tremity. With Distomum appendiculatum , the
two branches of the excretory organ unite directly
behind the oral sucker. With Aspidogaster con-
chicola , it divides into two canals near the Fora-
men caudale , which extend to the anterior ex-
tremity. In Amphistomum, two similar canals
wind from the head along each side of the body, to
the middle of the posterior back, where they open
outwards, after having formed by reunion a pyri-
form reservoir. Laurer (De Amphistomo conico.
p. 10, fig. 22) has given a figure of this reservoir,
in which he has confounded the secretory canals
with the nutritive vessels.

5 Beside Distomum hepaticum , Holostomum
urnigerum , the Distoma also with a spinous
head, have a widely-ramified excretory organ j see
Mehlis, Isis, 1831, p. 182.

6 With the spinous-headed Distomum militare,
and echinatum, this organ is often so reduced in
substance, that here and there are perceived only
isolated groups of the ramified canals.

7 The solidity of these corpuscles may have been
the reason why Ehrenberg (Symb. Physic. Anim.
Evertebr. Ser. I. Phytozoa entozoa) has taken those
of Cercaria ephemera for eggs, and the two canals
of the excretory organ for ovaries j and why
Nordmann (Microgr. Beitr. lift. 1, p. 54, Taf. I.
fig. 7) has regarded their escape from the body
with Distomum annuligerum, as an act of ovi-
position.

The corpuscles of this kind found in the excretory
organ of certain Trematodes, as for instance in a
larva of Monostomum known as Cercaria ephem-
era, remind one from their aspect, of the small
calcar . ous subcutaneous bodies of many 1 'aeniae,
and it may be asked if they are not an effete mate-
rial, which, not being contained in proper organs,
is with these IIelminthe3 thus subcutaneously
deposited.

8 This organ, to which I first called the attention
in the dissertation of Bagge (De evolutione S'.ron-
gyli auricularis et Ascaridis acuminatae, 1841, p.
13), is composed of two canals which run back-
wards in Strongylus auricularis , Ascaris brevi-
caudata, and acuminata (Bagge, loc. cit. fig. 30,
A. B.) •, and in Ascaris dactyluris, and pauci-
para, mihi (from the intestine of Testudo graced),
of two anterior and posterior canals, the common
opening of which is near the middle of the body.

§§ 114, 115.

THE HELMINTHES.

119

CHAPTER IX.

ORGANS OP GENERATION.

§ 114-

Although most of the Helminthes propagate by means of genital organs,
yet there are a few species which multiply by fissuration and gemmation.

The fissuration is always transverse, and differs from that of the Proto-
zoa and Zoophytes in the fact that complete individuals are not produced,
there being only a separation of certain organs from the perfect animal, as,
for instance that of the segments of the body in the Cestodes. This fissu-
ration is complete or incomplete. In the first case, occurring in the Taenia ,
the segments are detached from the body, and continue to live independ-
ently, without, however, ever forming a new individual.®

Gemmation has been observed in the sexless Coenurus and Echinococcus.

In Coenurus cerebralis, it is incomplete. The buds are formed on the
internal surface of the parent-vesicle, and never separate from ity nor
become perfect individuals. They have only a head and neck which pro-
ject outwardly after the complete development. In Echinococcus , however,
the gemmation is complete. The buds appear as in Coenurus, but the
young animals are sooner or later detached and fall into the liquid of the
parent vesicle. When completely developed, this vesicle bursts, and thoy
are set at liberty. That their development occurs in this way is shown by
their hanging by a cord, which, like the tail of Cercaria, is inserted into a
fossa at the posterior extremity of the body. Like this last, also, this cord
subsequently disappears, and the young animal moves freely about, by the
aid of its double circle of hooks and its four suckers.®

§ 115.

In those species which reproduce by male and female genital organs, these
last are sometimes upon a single animal, and sometimes upon two separate
individuals. The eggs and spermatic particles are formed after very differ-
ent types. In all, the copulatory organs are extraordinarily developed.

The Cestodes and Trematodes are hermaphrodites.® The structure of

1 The imperfect fissuration with Ligula and
Triaenophorus is limited almost to a constriction
of the lateral borders. With Bothriocephalus
punctatus , it is only here and there that a ring is
detached, and over most of the body the transverse
and opposite sulcations do not extend near to the
median line. With Bothriocephalus tetrapterus ,
the fissuration is more complete *, but even here,
there are only some incompletely limited rings
among numerous others which are completely so.

Of all Helminthes the Taeniae have the most
complete fissuration ; here not only is the separa-
tion of the rings indicated by a complete furrow,
but the rings are sometimes detached and live thus
independently. The separated rings of Taenia
solium , cucumerina , and others, move freely, and
are so individualized, that they resemble some
Trematodes.

2 See Chemnitz , He Hydatibus Echinococci
hominis commentatio, 1834 *, Muller, in his Arch.

1836, p. CVII. ; and Siebold , in Burdach's Phys-
iol. II. 1837, p. 183.

1 According to Nordmann (Microgr. Beitr. lift.
2, p. 141), Diesing (Ami. d. Wiener Mus. 1.
Abth. 1, p. 9), and Miram (Nov. Act. Acad.
XVII. pt. 2, p. 636), the male and female genital
organs of the genus Pentastomum , classed by
many modern Helminthologists among the Trema-
todes, are situated upon different individuals. But
Owen affirms to have observed the opposite
(Trans, of the Zool. Soc. of London, 1835, I. p.
325). The only way to settle this point is by
analyzing accurately the contents of these organs *,
a method pursued by Valentin (Repertorium III.

1837, p. 135), who found filamentoid spermatic
particles in the organs of an apparently female

120

THE HELMINTHES.

$115.

the genital organs of the first is yet imperfectly known ; while that of those
of the second is well understood. The female apparatus of the Tremato-
des consists of a germ-forming organ (ovary), with its excretory duct;
then, two others for forming the vitellus, which have also excretory
ducts ; and then a simple uterus with its vagina. The male apparatus con-
sists of testicles with their excretory canals, an internal seminal vesicle, a
cirrhus-sac, an external seminal vesicle, and a penis.®

The ovary consists of a round or pyriform ® reservoir, situated, usually,
upon the median line of the body,® from which it is distinguished by its
pale color and transparency. It is filled with simple round cells — the
egg-germs. The nucleus of these cells is the germinative vesicle, and the
nucleolus, the germinative dot.®

The short and small excretory duct of the ovary opens at the commence-
ment of the uterus. The organs which secrete the vitellus are two in num-
ber, of variable length, and situated upon each side of the body near the
dorsal surface ; they occupy either the cervical, the central, or the posterior
portion of the animal, and sometimes extend over them all. They are
nearly always composed of ramified caeca filled with white, granular,
vitelline corpuscles. By reflected light these caeca appear through the
skin as a white, ramified, botryoidal mass,® and from each of them, pass
off inwardly, numerous excretory ducts, which reunite opposite the ovary
into two common canals. These last approach each other transversely,
and form a single canal upon the median line, which, after a short course,
opens at the bottom of the uterus by an orifice which is common to it and
the ovary.®

Pentastomum taenioides , organs which are re-
garded by Diesing as caeca for secreting the en-
velope of the eggs.

Since all the parts of the genital organs of Pen-
tastomum have not been examined with this same
precision, I can give no opinion as to their use.*

2 See Siebold , in Wiesmann's Arch. 1836, I. p.
217, Taf. VI., and in Muller's Arch. 1836, p. 232,
Taf. X. fig. 1.

3 The ovary here is always smaller than the
testicle, and sometimes as to form very closely
resembles it, as in Distomum globiporum , and
longicolle, mihi (from the urinary bladder of
Cottus gobio ) ; consequently it may easily be
taken for a third testicle.

4 With Monostomum , it lies wholly at the pos-
terior extremity.

5 In Polystomum , Octobothrium and Diplo-
zoon , the germs are so large that they may easily
be taken for perfect eggs.

There is here, moreover, between the cell-wall
and the nucleus (the germinative vesicle), quite a
thick layer of albuminous substance, somewhat

representing a vitellus. But in the other Trema-
todes it is so thin as scarcely to be perceived.

0 With the following Trematodes there is a wide
deviation from this usual arrangement. In Dis-
tomum longicolle the organs producing the
vitellus are two simple round caeca located behind
the ventral sucker ; in Distomum cygnoides ,
they are two very small deeply-fissured bodies j
and in Distomum gibbosum , there is one only,
which is star-shaped and located nt the middle of
the body.

7 These organs, until now regarded as ovaries,
secrete only vitelline cells. With most Trematodes
their nuclei are clear, and have been taken for
eggs. In eggs recently formed, one can always
distinguish these cells from the germs. In passing
the excretory canals they are compressed and
elongated, but never run into each other. When
these canals are crowded, they have the aspect of
white cords, which have often been taken for
nerves. But when they are empty, they, as well
as the vitellus-segreting organs, are almost invis-
ible.!

* [ § 115, note 1.] See upon this subject Van
Beneden (Ann. d. Sc. Nat. XI. 1849, p. 326), who
has described in detail the sexual organs of Lin-
guatula Diesingii , and has shown the sexes to be
separate. See also my note under § 99. — Ed.

t[§ 115, note 7.] To say that certain organs
secrete vitelline cells, is a little obscure, and no
doubt Siebold intended to convey the meaning
that they secreted the plastic material out of which
these cells are formed. I make _ this perhaps
seemingly unnecessary reference to the matter,
since it concerns the subject of the development of
the ovum. In the Ascaris , where the origin and
development of the ovum can be satisfactorily

studied, you first notice the germs as nucleolated
cells, of which the nucleus is the future germina-
tive vesicle and the nucleolus the germinative dot.
These cells jncrease in size, and as they move
along there appear in the liquid which lies between
the nucleus and the cell-wall minute granules
which ultimately become cells ; in this way the
vitellus is formed, the formation being endogenous
and not exogenous. These special organs or
tubes therefore are vitellus-forming organs, in vir-
tue of their secreting the formative material out
of which the vitellus is formed within the original,
nucleolated germ-cell. — Ed.

§115.

THE HELMINTHES.

121

The neck of the internal seminal vesicle ( Vesicula seminalis interior ),
discharges its contents at this same place into the uterus, through a special
Vas deferens from one of the testicles. The Uterus commences as a narrow
tube, which may be regarded as a Tula Fallopii. Its dilated portion,
which has powerful peristaltic motions notwithstanding its thin walls, is
throughout of nearly an equal diameter. It winds through a large portion
of the body and terminates iu a narrow, more or less straight, muscular
vagina, which always opens externally by the side of the penis.®

The testicles, of which there are usually two,® are generally of a round
or oval form/101 and located in the posterior region of the body, nearly
always one before the other. ai) They are transparent and colorless, and
the filiform spermatic particles are extremely small and active. <12> The
two Vasa deferentia open into the cirrhus-sac, which is perforated at its
bottom to communicate with the Vesicula seminalis exterior .(13) From
each testicle there passes off, also, a third Vas deferens which opens into
the neck of the Vesicula seminalis interior .(14) The cirrhus-sac is pyri-
formjiy elongate, or round, (IS) and the Vesicula seminalis exterior is always
situated at its base. This last is prolonged, opposite the openings of the
vasa deferentia, into usually a very long, tortuous Ductus ejaculatorius,
which opens into a tubular penis/1® There is one common genital open-
ing for the penis and vagina which are usually side by side, and out of
which the penis often considerably projects. (17) In most Trematodes, these
two organs are located at the anterior extremity of the body, and only in
Holostomum, and Gasterostomum , are they removed to the other extrem-
ity/1®

8 The length of the uterus varies very much in
different genera and species, and its coils are
always irregular. With Monostomum mutabile ,
and verrucosum , the oviduct arising in the poste-
rior extremity, passes in front with numerous
transverse coils.

9 I have found one testicle only, in Amphisto-
mum subclavatum , and Aspidogasler conchicola ,
although I have seen three or four in Distomum
appendiculatum , and cygnoides.

10 With Distomum ovatum , the two testicles are
side by side behind the ventral sucker •, with Dis-
tomum chilostomum , they are on each side of this
sucker, and with Distomum crassum , mihi (from
the intestine of Hirundo domcstica ), they are in
front of it, on each side of the neck.

11 With Distomum longicolle , lanceolatum ,

oxyurum, echihatum, globiporum , and Amphis-
tomum conic urn, the testicles have many depres-
sions •, see Bojanus, Isis, 1821, Taf. II. fig. 25-27 ;
Burmeister and Sieltold , in IViegmanns Arch.
1835, II. Taf. II. 1836, I. Taf. VI. ; also Laurer}
De Amphistomo conico. lig. 21, 24, 25. With
Amjihistomjim subtriquetrum , giganteum , and
Distomum Ilians , the number and depth of these
depressions gives the testicle the aspect of a bundle
of caeca ; see Bojanus , loc. cit. Taf. II. lig. 14-17,
and Diesing Ann. d. Wiener Mus. I. Abth. 2,
Taf. XXII. ,

12 In the testicles of the Trematodes, the devel-
opment of the spermatic particles occurs after the
usual mode.

The bundles which they form are separated in
their passing the vasa deferentia, and they collect
into irregular masses in the seminal vesicles.

Their extremely active movements cannot be

* [ § 115, note 12.] Thaer ( Muller's Arch. 1850,
p. 602, Taf. XXI. fig. 19) has described and fig-

li

perceived unless they are quite isolated. When
put in water they become twisted together, and
assume a loop-like arrangement, — their motions
instantly ceasing.

For the development of the spermatic particles
of the Trematodes, see Kolliker , Die Bildung du
Saamenfliden in Blaschen, loc. cit. p. 44, fig. 31.*

13 These two vasa deferentia are sometimes
blended together before reaching their destina-
tion } this is so in Distomum variegatum , and
longicolle.

14 The internal seminal vesicle is so extraordi-
narily large in Distomum variegatum that it
exceeds that of the ovary and two testicles.

15 This cirrhus-sac, together with the penis, is
very long with Distomum lima , maculosum ,
variegatum , and ovatum ; but it is especially so
with Aspidogaster conchicola , and Monostomum
verrucosum.

1G The protruding cirrhus or penis of Distomum
holostomum is provided with small bunches 5 and
that of Monostomum verrucosum with num-
berless little warts.

17 When the penis is protruded, it may then be
seen how the contents of the vagina are emptied at
its base. When the common genital opening is
closed, the very flexible penis can be turned into the
vagina and there discharge its contents, and in
this way the self-impregnation of these animals
may occur.

18 The common genital opening is usually sit-
uated on the middle of the neck, and with Dis-
tomum, it is directly in front of the ventral sucker.

With Distomum clavigerum, and ovatum , it is
upon the sides of the neck, and with Distomum
caudale , and holostomum , exceptionably, it is on

ured the spermatic particles of Polystomum ap-
pendiculatum as Cercaria-form. — Ed.

122

TIIE IIELMTNTHES.

§ 115.

In the terminal, constricted portion of the uterus, eggs, vitelline cells,
and spermatic particles are often found mixed together. It is probably here
that the eggs are formed, their fecundation occurring without copulation,
and by means of the Vesicula seminalis interior. The succeeding folds of
the uterus contain already, nicely-defined, oval eggs containing a germ and
many vitelline cells. Their recently-formed envelope is still colorless, and so
thin and flexible, that the peristaltic contractions, of the uterus give it a
variety of forms. But in passing from the uterus they lose this flexibility ;
their envelope becomes more solid, — of a yellow and then a brown color;
and the whole, at the same time, undergoes a decrease in size, due prob-
ably to a condensation ofljjtheir substance. The eggs of most of the Trema-
todes have an opercular opening at one extremity. (19>

In the Cestodes, the walls of the genital organs are so very thin, and so
intimately blended with the parenchyma of the body, that their structure
and relations have not yet been well made out.

With the exception of in Caryophyllaeus, (20) these organs are repeated many
times one after another, having in the same individual different deglfjes of
development. They are always most complete in the posterior portion of
the body, being only rudimentary near the neck, while in the neck itself
they do not exist at all. In the articulated Cestodes, each ring contains
both male and female sexual organs ; and in their two Groups, the arrange-
ment of these is the same as in the Trematodes. It is probable that the
ovaries and the secreting organs of the vitellus are separate. (21) In Ligula,
Triaertophorus , and Bothriocephalus , the uterus consists, exactly as in the
Trematodes, of a very tortuous tube filled with oval eggs.(22> But in

the posterior extremity of the body. Its position
is indicated, even when the penis is not protruded,
by a small papilla.

With Octobothrium , and Polystomum ., there
is a round muscular sac concealed directly behind
this opening, which contains a circle of delicate
horny ribs, the lower extremities of which are
bifid and form a support like a bownet. Mayer
(Beitr. loc. cit. p. 21, Taf. III. fig. 3, 6) has seen
ten similar ribs with Octobothrium lanccolatum.
I have found eight with Polystomum integerri-
rnum, and forty with Polystomum ocellatum.
Their use is wholly unknown to me.

19 The eggs of the Trematodes have apparently
only a single envelope. Among the normal eggs in
the uterus may often be found others which are mal-
formed, also very irregular bodies of a yellowish or
brown color, formed almost entirely of the sub-
stance of these envelopes. These bodies were
most probably secreted by the walls of the uterus
(the Tuba Fallopii ) at a time when the ovaries and
the secreting organs of the vitellus were inactive,
so that the substance of the envelopes was hard-
ened before receiving their usual contents. With
Amphistomum subclavatum , Octobothrium lan-
ceolatum , Polystomum integerrimum , and ocel-
latum , and Diplozoon paradoxum , the eggs are
very large, and in the last-named species their ex-
tremities are narrowed and lengthened into a spiral
filament, wherefore one of these eggs has been taken
for a testicle and penis ; see Nordmann Microgr.
Beitr. lift. 1, p. 73, Taf. Y. VI. fig. 1, h.$ also Togt,
in Muller's Arch. 1841, p. 34, Taf. II. fig. 11.

The eggs of Monostomum verrucosum , and
some other species of this genus which live in the
intestine of Chelonia esculenta , have a very dif-

* [§ 115, note 19.] See also for the structure of
the genital organs Thaer, Muller's Arch. 1850,

ferent form •, they are oval and colorless, and at
each extremity have two papillae, which are grad-
ually developed into very long, sharp appendages •,
see Dujardin , Hist. Nat. d. Helminth. PI. VIII.
fig. G, B. 3 *

20 With Caryophyllaeus mutabilis , there is only
a single cirrhus-sac upon the ventral surface of the
posterior body, and from which a delicate long
penis often protrudes.

21 I think I have seen an ovary in each of the
segments of Bothriocephalus punctatus, and Tae-
nia ocellata. As such, ought, perhaps, to be re-
garded those organs which Eschricht (Nov. Act.
Acad. Leop. XIX. Suppl. 2, Tab. I. fig. 2, e, e)
has considered with Bothriocephalus latus to be
ovaries. The organs secreting the vitellus are a
mass of irregularly arranged granulations situated
upon both the dorsal and the ventral surfaces, and
which have very fine excretory ducts. This mass,
called by Eschricht (loc. cit. p. 25, Tab. I. fig. 5)
the ventral and dorsal granules, cannot, together
with its excretory ducts, be made out, except when
filled with the vitelline substance, ^ith Taenia
ocellata , the vitelline organs are limited to the
sides of each segment, at the anterior border of
which two main excretory ducts are easily seen ;
these form a single short canal in the middle of the
body. In this same place are two transversely-
placed oval sacs, and which are probably the two
ovaries.

22 The uterine convolutions are generally in the
middle of the body, and when filled with mature
eggs, appear through the skin as a brown rosette ;
see Eschricht loc. cit. Tab. I. II. ( Bothriocepha-
lus latus).

p. 602, Taf. XX. fig. 17 ( Polystomum appcndi -
culatum). — Ed.

§115.

TUB HELMINTHE3.

123

Taenia , it is a reservoir, composed of numerous ramified coeca, and inti-
mately blended with the parenchyma of the body.(23) The vagina is a nar-
row, muscular canal, which usually opens close to the penis by a special
orifice (Vulva), or by a common genital opening ( Porus genitalis).

It is difficult to decide whether the testicles, which always form the
middle layer of the body, consist of a collection of inter-opening caeca, or
of a single spirally-rolled tube. The cirrhus-sac with the Vas deferens open-
ing at its bottom, is always very distinct. As in the Trematodes, it has a
Vesicula serninalis, with a Ductus ejaculatorius and a muscular penis. (24)
The contents of the different canals, the seminal vesicle and the ejacula-
tory duct, are always very active, filiform spermatic particles. (-s> The
genital openings are upon the middle of the ventral surface, or on the
lateral borders of the body ; but in those species where the sexual openings
are separate, they are lateral for the male, and ventral for the female. (S6)

The e"2;s of the Cestodes, situated like those of the Trematodes in a
spiral, pouch-like uterus, have also a similar structure. Their simple, oval,
brownish-yellow envelope, has also, sometimes, an operculum. The eggs
of Taenia have a very different structure ; the envelope is colorless, and
of a very variable, and sometimes quite remarkable form.(27)

23 With most Taeniae the borders of the cellular
uterus are very difficult to distinguish. But its
lateral caeca with Taenia ocetlata, and its arbo-
rescent divisions with Taenia solium , are very
easily seen *, see Delle Chiaje , Compendio di
Ehnintografia umana, Tav. III. fig. 10.

24 The cirrhas-sac is either sltf>rt and pyriform,
or very long. With very many Taeniae, as with
Taenia amp hi trie a, lanceolata, multistriata ,
scolecina , and setigera, the penis has numerous
small spines pointing backwards ; see Dujardin,
Hist. d. Helm. PI. IX.-XI. That of Taenia
infundibuliformis is surrounded with very large
bristles 5 and according to Dujardin (loc. cit. PI.
IX. B. 210) this is also true with Taenia sinuosa.

25 By very slight pressure, the spermatic parti-
cles contained in the Vesicula serninalis of the
cirrhus-sac are pressed out through the penis •,
this is so with Bothriocephalus punctatus, latus ,
Taenia cucumerina, planiceps (from the intes-
tine of Hirundo urbica ), inflata , pectinata , ser-
pentulus, and villosus. As with the Trematodes,
the spermatic particles here cease to move when
put in water, and are twisted into loops.*

26 With Ligula , Bothriocephalus nodosus ,
latus , claviceps , ditremus , punctatus , and te-
trapterus, the two genital openings are situated
on each side of the ventral surface, while the penis
protrudes from a special opening directly in front
of the vulva •, see Mehlis in Isis, 1831, Taf. I. fig.
1, 2, and Eschricht , loc. cit. Tab. I. fig. 5.

With Bothriocephalus punctatus , there are
two pairs of these openings upon each segment,
one under the other, but in Bothriocephalus te-
trapterus, these are side by side. With Triaeno-
phorus , nodulosus,nn(\ Taenia ocellata, the vulva
is upon the ventral surface, and the penis upon
the lateral border. With Bothriocephalus fra -

* [ § 115, note 25.] I have observed the de-
velopment of the spermatic particles with Taenia.
They are developed in special cells, and before
they have escaped, are therein coiled up resembling
those of the coleopterous insects. They are simply
filiform. — Ed.

t [ § 115, note 26.] The Cestodes have been the
objects of much careful study during the last few

gilts , proboscideus , rugosus , and with most Tae-
niae, the cirrhus-sac and the vagina open by a
common genital orifice upon the lateral border,
and usually through a papilla. With Taenia
cucumerina, and bifaria, mihi (from the intestine
of Anas leucophthalmus ), I have found an orifice
of this kind upon the two lateral borders of each
segment, and behind which were the genital or-
gans.!

27 Although I have not seen either the germina-
tive vesicle or dot in the eggs of the Cestodes,
probably from their delicacy, yet I do not for a
moment doubt their presence there, since Kblliker
(Muller's Arch. 1843, p. 92, Taf. YII. fig. 44) has
seen them in the eggs of a Bothriocephalus.
Many species of this genus produce oval eggs
which have a simple brown envelope. Of an oval
form, but colorless, are those of Caryophyllaeus ,
Ligula, Triaenophorus, Taenia literata, and
scolecina. Those of Taenia amphitricha, bifa-
ria, macrorhyncha, serpentulus , and serrata, are
round, and have two colorless envelopes ; this is true
also of the oval eggs of Taenia angulata, villosa ,
6fC. There are three of these envelopes with the
round or oval eggs of Bothriocephalus infundibul-
iformis, proboscideus , Taenia porosa, lancco -
lata, ocellata, setigera, and solium. With Tae-
nia infundibuliformis, and planiceps, each ex-
tremity of the envelope is lengthened into a long
and delicate appendage. Two similar but fibril-
lated appendages exist upon those of Taenia
variabilis. With Taenia cyathiformis , the ex-
ternal pyriform envelope of the eggs has, at its
attenuated extremity, two round, bladder-like ap-
pendages. Dujardin (Hist. d. Helm. FI. IX.-
XII.) and I (Burdach's Physiol. 1837, II. p. 201)
have seen many other forms with the eggs of
Taenia. The round and doubly-enveloped eggs

years, by Blanchard (Ann. d. Sc. Nat. X. 1848,
p. 321) and Van Benedcn (Mem. Acad. Belgique,
1850, XXY.) and the sexual parts pretty clearly
made out. They both agree that, internally, the
male and female organs are wholly distinct, and
therefore that impregnation of the ova must be by
self-copulation. — Ed.

124

THE HELMINTHES.

§116.

§116.

In the Aeanthocephali, the genital organs occupy a large portion of the
cavity of the body. They arise in the posterior portion, and are supported
by a Ligamentum suspensorium,* which extends from this last to the base
of the proboscideal sheath.

In the females, there are neither proper ovaries, nor an uterus ; but in
their place there are numerous oval, or round, flattened bodies of consider-
able size, which float freely in the liquid of the cavity of the body ; they
have nicely-defined borders, and are composed of a vesicular, granular
substance, and, as eggs are formed within them, they may be regarded as
so many loose ovaries. a>

When the eggs have reached a certain size, they fall from the ovaries
into the cavity of the body. At this time they are ovo-elongate, have
only a single envelope, and contain both a vesicular and a finely-granular
substance, but no trace of a germinative vesicle. They continue to in-
crease in size, and two new envelopes are formed about them.(2) The
muscular canal which passes off from the simple vulva which is situated at
the posterior part of the body, may be regarded as a uterus.

At the point where it is attached to the Ligamentum suspensorium, it
becomes a campanulate or infundibuliform organ, whose borders float freely
in the cavity of the body, and thus the whole is comparable to a Tuba Fal-
lopii. The bottom of this bell-shaped organ communicates with the
superior extremity of the uterus by a narrow, valvular opening, which
presents a lateral, semilunar fissure.

This whole organ is endowed with very active peristaltic motions, by
which the loose contents of the cavity of the body are absorbed ; and while
the larger ovaries are thrown out, the little immature eggs are returned into
the cavity of the body by the lateral fissure, — the more mature ones only,
reaching the uterus.® This uterus, which is of variable length, opens
outwardly through a very short and narrow vagina.

The males of Echinorhynchus have usually two oval or elongated testi-
cles, one before the other, and attached to the Ligamentum suspensorium.

of Taenia cucumerina ( Creplin , Observ. de
Entozois fig. 12, 13) and crater if ormis, have the
remarkable arrangement of being grouped in tens
to twenties, and each group is surrounded by a
gelatinous envelope.*

1 The ovaries of Echinorynchus were formerly
taken both for mature eggs, and for cotyledons ;
and to this is due the very inaccurate figures of
them by W estrumb and Cloquet (loc. cit.). Du-
jardin , however (Ilist. d. Helm. PI. VII. fig. D.
6), perceived their true nature.

A state of development which I have observed
with many females of Echinorhynchus gibbosus ,
would appear to throw some light upon the ques-
tion as to the part of the body where the ovaries
are first formed. Here the Ligamentum suspen-
sorium had, over most of its extent, large granu-
lar globules, while the cavity of the body contained
neither ovaries nor eggs. I think, therefore, that
this ligament is the elementary material from which
the ovaries are developed under the form of glob-
ules, which, being subsequently detached, continue
their development in the liquid of the cavity of the
body.

* [§115, note 27.] See Van Bencden (loc. cit.
p. 67), who has observed the eggs of the Cestodes

2 The long eggs of many Echinorhynchi are
formed by the same process. They are all colorless,
and may be distinguished by the peculiar aspect
of their middle envelope which at both extremities
is constricted like a neck. Hut those of Echino-
rhynchus gigas form an exception ; for they are
shorter and oval, their middle envelope is yellowish,
and, like the two others, has externally numberless
small obtuse spines. With Echinorhynchus stru-
mosus , hystrix , angustatus , and proteus, the
external envelope of the eggs presents the peculiar
phenomenon that when pressed between two plates
of glass, it separates into very fine fibrillae.

3 The nature of this campanulate Tuba Fallopii
has been wholly mistaken by Bojanus1 fVestrumb
and Cloquet. Burow (Echinorhynchi strumosi
Anat. p. 22, fig. 1. g, fig. 6) was the first to
describe it, without however conveying the correct
idea. See my description ( Burdach's Physiol,
loc. cit. p. 197), which has been confirmed since
by Dujardin (Hist. d. Helm. p. 495, PI. VII. fig.
D. 5).

composed like those other animals, — with a germin-
ative vesicle, &c. — Ed.

§ 117.

THE HELMINTHES.

125

tf

They send off two varicose Vasa deferentia to the posterior portion of
the body, where, after uniting very probably with the neck of an odd
elongated vesicle ( Vesicvla seminalis ?), they are prolonged into a copula-
tory organ.® There are six pyriform bodies, which secrete a finely-granu-
lar substance, and are attached behind the testicles to the Vasa deferentia.
Their six excretory ducts successively unite, ending finally in two which
open into the copulatory organ.® The penis is usually folded inward, but
when projecting outwardly, it is a muscular, cup-shaped appendage, whose
fossa receives the posterior portion of the body of the female during
copulation.®

The spermatic particles are developed after the usual mode ; they are
filiform and very active, and quickly die iu water, interlooping and
twisting together.®

The very adhesive, viscous, yellowish-brown wax-like substance, often
found about the vulva, is apparently the secretion of the pyriform bodies
during copulation.®

§

With the Nematodes, the genital organs consist of a long, simple or
partly double caecal tube, which winds around the straight intestine.

In the female it has the following parts : Ovarium , Tuba FaUopii,
Uterus, and Vagina; and in the male, Testes, Vas deferens, Vesicula
seminalis, and Ductus ejaculatorius.

With Trichosoma, Trichocepkalus, and Sphaerularia, the genital tube is
simple in the females, and usually so in the males. But in Filaria , Asca-
ris, Strongylus, Spiroptera, Oxyuris, and Anguillula , the ovary, Fallopi-
an tube, and uterus, are double. (1> In the females, the ovary is the poste-
rior portion of this genital tube, and in its terminal portion are small round

4 "With Echinorhynchus strumosus , these two
round testicles are side by side. Having always
found the odd, long vesicle empty, I cannot decide
whether or not it serves the function of a seminal
vesicle.

5 These six pyriform bodies were formerly taken
for seminal vesicles } see fVestrumb , de Helminth.
Acanthocephalis, p. 55, Tab. III. fig. 24 •, and
Nitzsch , in Ersch and Gruber's Encyclop. VII.
1821, plate for the Acanthocephala, fig. 2, 3, i.
With Ecninorhynchus claviceps , I have found
only one of these bodies.

6 The copulatory organ, which protruded has
mostly an oblique direction, has been very exactly
figured by Dujardin (Hist. d. Helm. p. 493, PI.
VII. fig. D, 1, D, 2).

7 For the spermatic particles of the Acanthoce-
phali, see my observations in Muller's Arch.
1836, p. 232.

8 This waxy substance incrusts sometimes the
whole caudal extremity of females •, this is so with
Echinorhynchus gigas, and globocaudatus ; see
Cloquet (Anat. &c. &c. p? 100, PI. VIII. fig.
4, 5) and Nitzsch ( Wiegmann's Arch. 1837, I.
p. 64.*

1 For the simple genital tube with its various
parts of the female of Trichocepkalus dispar , see
Mayer , Beitr. &c. Taf. II. With Filaria rigida ,

* [ § 116, note 8.] For some further details on
the genitalia of the Acanthocephali, see Blanchard
(Ann. d. Sc. Nat. 1849, XII. p. 23), and R£gne

n*

and Asc.aris paucipara , I have found the female
organs likewise simple. When these organs are
double, either one uterus with its ovary and ovi-
duct passes in front from the simple vagina, while
the other passes behind, as is the case with Ascaris
brevicaudata , nigrovenosa , Oxyuris vermicu-
laris , Spiroptera anthuris , Strongylus auricu-
laris , and striatus ; or both pass side by side
behind, as in Ascaris aucta, mystax , lumbri-
coides ( Cloquet , Anat. &c. PI. I. fig. 2) and aus-
culata. With Cuculfanus elegans , and micro -
cephalus (from the intestine of Emys lutaria\
the uterus alone is double *, one horn terminating
posteriorly in a caecum without an ovary or Fallo-
pian tube, while the other, which has these parts,
passes in front. There are, moreover, species of
Ascaris into whose vagina open three or four geni-
tal tubes. Thus with Ascaris microcephala , I
have seen the uterus divide upon reaching the
vagina into three tubes, each having an ovary and
oviduct. According to Nathusius ( Wiegmann's
Arch. 1837, I. p. 57), the uterus of Filaria labiata ,
which is at first simple, divides at its posterior ex-
tremity into five tubes.

The double uterus of Strongylus inflexus has,
posteriorly, numerous constrictions, giving it a
moiTiliform aspect.

animal nouv. Mit. Zoophytes, PI. XXXV. fig. 3bf
3c, 3d, 3e, 3f). — Ed.

126

THE HELMINTHES.

§ 117.

cells; in the anterior portion, these cells are more numerous and begin to
be surrounded by a granular vitelline substance, in which the primitive
nucleated cells are still seen ; these cells therefore, ought perhaps to be
regarded as germinative vesicles. In front, these eggs, which are of a dis-
coidal form, are arranged in a row, or are grouped closely around a rachi#
which traverses the axis of the ovary. In the Fallopian tube, which may
be known by its less diameter, the eggs become more mature, and, having
been surrounded by a double colorless envelope, pass into the base of the
uterus. (2) This last is the largest portion of the genital tube, and is dis-
tinguished by its well-marked power of peristaltic action. The vagina,
which is distinguished from the uterus by its narrowness and its muscular
walls, opens at very different points of the body. Generally, as for
instance in Ascaris , Spiroptera, Strongylus, Oxyuris, Cucullanus, and Tri-
chocephalus, the Vulva, consisting of a transverse fissure, and often sur-
rounded by a very remarkable fleshy swelling, is situated either a little in
front of, or near the middle of the body ; but sometimes it opens just in front
of the anus.(3) The sperm is usually so accumulated in the bottom of the
uterus, that this is probably the locality of fecundation. (4)

In the males, ^he posterior portion of this tube is the testicle; another
portion of it, which is short and constricted, is the Vas deferens, which
passes into a dilated portion, — the Vesicula scminalis. Usually this last is
separated by a constriction from the Ductus ejaculatorius, which opens into
another muscular tube (sheath of the penis).® At' the anterior portion of
this last, is a horny, copulatory apparatus. The simple or double penis is
of variable length, and isf. protruded by the muscular contractions of its
sheath through the external opening, which is always situated at the poste-

4 /

borders of the vulva appear quite swollen. With
Trichosoma , this swelling is so attached to the
vulva as to resemble a prolapsus of the vagina
( Dujardin , Ilist. d. Helm. PI. I.).

With Filaria attenuatci, injlexo-caudata , mihi
(from the pulmonary cysts of JJelphinus pho-
caena ), and papillosd (see Leblond , Quelques
materiaux pour servir & l’histoire des FiJaires et
des Strangles, 1836, PI. II. fig. 1), the vulva is at
the side of the mouth.

With Strongylus paradoxus , it is swollen to the
form of a bladder, and is situated near the caudal
extremity ; while that of Ascaris paucipara is
directly upon the anus.

4 See Bagge , loc. cit. p. 12 ; and KOlliker , in
Muller's Arch. 1843, p. 72.

5 For the male genital tube, see Mayer , Beitr.
Taf. I., and Cloquet , Anat. &c. PI. I. fig. 5, PI.
II. fig. 8. As yet I have observed only a few
exceptions to this typical form with male Nema-
todes.

With Filar ia attenuata , the posterior portion
of the testicle is bifurcate, and with Ascaris vesi-
cularis , there are two moderately large caecal pro-
longations which arise from the Vesicula semi -
nalis at the place where it empties into the Vas
deferens.

become developed into cells, and in this way the
mature ova are formed. Probably no better op-
portunity is afforded to perceive that morphologi-
cally the ovum is at first only a nucleolated or
nucleated cell ; see Leidy , loc. cit. p. 43, PI. VII.
fig. 14, c. — Ed.

2 The formation of eggs in various Nematodes
has been described by Siebold ( Burdach's Phys-
iol. loc. cit. p. 208), by Bagge (Dissert, de. Stron-
gylo, &c., fig. 1-5), and Kbllifcer ( Muller's Arch.
1843, p. 69, Taf. VI. fig. 20). I have found a
racliis in the ovaries of Ascaris aucta , lumbri -
coides , my stax , osculata , Cucullanus elegans ,
and Strongylus inflexus. The eggs of these,
while yet immature and flattened, have a point on
one of their extremities by which they are attached
to the rachis.

With those of Ascaris lumbricoides , this point
is very long during a certain period of develop-
ment, and the opposite end has many deep sulca-
tions, giving it a remarkable appearance ; see
Henle , in Muller's Arch. 1835, p. 602, Taf. XIV.
fig. 11.

In the mature eggs, which are nearly always oval,
it is rare that the double colorless envelope can be
clearly perceived. With Trichosoma , and Tri-
choc ephalus , there is a short diverticulum at each
extremity of the egg. But in Ascaris dentata ,
there is at this same place a long fibrillated filament;
see Mayer , Beitr. Taf. II. fig. 8, and K’Olliker ,
in Muller's Arch. 1843, Taf. VI. fig. 16-19.*

3 With Ascaris dactyluris , Cucullanus ele-
gatis , Strongylus nodularis , and striatus , the

* [§ 117, note 2.] Primitively, the ova of Asca-
ris consist of nucleolated cells, which are pol^he-
vdral from mutual pressure. These increasedn size
gradually, in their passage down towards tne ovi-
duct, and the granules of the liquid lying between
the nucleus or germinative vesicle and the cell-wall

§ 117.

THE HELMINTHES.

127

rior portion of the body.® It has a great variety of forms, and from its
sheath arise t.wo antagonistic muscles, which are inserted at its base.® The
spermatic particles, which are always motionless, have usually a cell-form,
or, at least, are never filiform corpuscles.® For aiding the union of the
sexes during copulation, the males have lobular appendages, papillae, and
suckers, situated about the genital opening. Without doubt, the spiral pos-
terior extremity also of the animal, is often used for the same purpose.
Moreover, in many instances, there is secreted a wax-like substance in-
tended to fasten the two sexes together.®

6 According to Leblond (loc. cit. p. 20, PI. III.
fig. 1), both the male and female genital opening's
with Filaria papillosa are quite near the oral ori-
fice. I ha ve^ been unable to confirm this observa-
tion, at least with Filaria attenuata , inflexo-cau-
data , and another species found in the thoracic

‘ cavity of Sturnus vulgaris.

7 With Trichoc ephalus, and Trichosoma , the
penis is simple and very long, and, beside the mus-
cular sheath, has another which is membranous,
and sometimes covered with small spines pointing
backwards. This sheath, being folded outwards
when the penis is protruded, is comparable to a
Praeputium j see Mayer, Beitr. loc. cit. Taf. I.,
and JJujardin , Hist. d. Helm. PI. I. -III. With
nearly all the other Nematodes the penis is double.
It is very long with Ascaris acuminata , brevi-
caudata , depressa , spiculigera , and Strongylus
paradoxus ; but is very short with, Ascaris ensi-
caudata , semiteres , Cucullanus elegans , Fila-
ria attenuata , injlexo-caudata , Spiroptera an-
thuris , and Strongylus injlexus. With Spirop-
tera, the two penises are of unequal length, and
with Ascaris paucipara, brevicaudata, and Stron-
gylus, there is an additional horny piece like a
third penis.

With most Nematodes, the penises are sulcated,
and those of Strongylus have a singular form due
to the presence of numerous appendages. The two
delicate, retractor muscles of this organ, arise from
the internal surface of the cavity of the body, and
when the penis is double there are two pairs.

With Ascaris osculata, vesicularis , and spicu-
ligera, I have found these four muscles very long.
See upon the penis of the Nematodes, Mayer,
Beitr. Taf. I., and Du jar din , Hist. d. Helm. PI.
I.-VI.

8 For the spermatic particles of the Nematodes,
see Bagge, Dissert, de Strongylo, &c., p. 12,
fig. 27, 23. The development of these cell-like
spermatic particles may be easily observed with
Ascaris paucipara, where the parent-cells are
very large. In the posterior end of the testicle the

* [ § 117, note 8.] The statement here made that
Reichert has observed the development of the'
spermatic particles of an Ascaris by fours in each
cell, deserves attention from its histological relation.
According to my own observations, the histological
formative conditions of the development of the
spermatic particle are exactly analogous to those
of the development of the. embryo. The nucleus
of the sperm-cell divides or segments like the vitel-
lus of the ovum, and this process continues until
the sperm-cell which has now attained a large size,
is filled with numerous small nucleated cells
(daughter-cells) 5 and the nucleus of these last is
changed into the spermatic particle.

I think, therefore, that, invariably, the spermatic
particle is only a metamorphosed nucleus of a

nuclei with their nucleoli are first formed 5 after-
wards these nuclei are surrounded by a finely-
granular substance around which the cell-mem-
brane is formed.

In this state the testicle exactly resembles an
ovary filled with germinative vesicles and eggs.
Still later, the parent-cell membrane increases more
and more, and the granular substance is found
only upon the internal surface of the cell. During
these changes, the nucleus which resembles a ger-
minative vesicle,- is transformed into a long, solid,
and neatly-circumscribed corpuscle. With Stron-
gylus auricularis, the spermatozoal [laughter ?]
cells are pyriform •, and with Oxyuris ambigua
theh form is similar ( Kblliker , loc. cit. p. 73, Taf.
VII. fig. 26).

It is very probable that Mayer's assertion (Neue
Untersuch. aus dem Gebiete der Anat. u. Physiol.
1842, p. 9) that he had seen thread-like spermatic
particles with Oxyuris vermicularis , has led
Kblliker t6 regard these pyriform cells as so many
bundles of filamentoid spermatic particles. But
never have I seen filaments of this kind in the Ne-
matodes.

The pyriform spermatic particles of Strongylus
auricularis, which have a short peduncle, as well
as the round, cell-like, and nucleated ones of As-
caris acuminata, have been figured by Reichert
(Beitr. zur Entwickel. der Saamenkdrp. bei den
Nematoden). This same naturalist has shown that
these spermatic particles arise by endogenous gen-
eration, by fours in each cell 5 see Muller's Arch.
1847, p. 88, Taf. VI*

9 The large caudal valve of the male Strongylus,
and the spiral tail of the male Spiroptera , may be
here instanced. With very many male Ascaris ,
there are two rows of papillae upon the sides of Che
genital opening, and with Ascaris vesicularis ,
and inflexa, I have found a copulatory sucker
directly in front of this opening. The male of
Hedruris androphora winds himself about the
female during copulation, and the caudal valve of
the male Strongylus trachealis glues itself so

daughter-cell (see my Memoir, The Origin, De-
velopment, and Nature of the Spermatic Particles
in the four classes of Vertebrata, in the Mein.
Amer. Acad, of Arts and Sc. V. 1853). The view
of Reichert , therefore, that four spermatic parti-
cles are here formed in one cell, does not appear to
me admissible, although I have no observations
upon the instance in question. It appears to me
explicable in this way : the nucleus of the parent
sperm-cell underwent here only a second segment-
ation, thereby only four daughter-cells being pro-
duced. The nucleus of each of these became a
spermatic particle, and these four particles passed
into the cavity of the parent-cell. Reichert there-
fore, probably saw four spermatic particles in a
parent and not in a daughter cell. — Ed.

128

THE HELMINTHES.

$ 118.

The few observations hitherto made upon the genital organs of the Gor-
diacei have shown that they are wholly tubular as in the Nematodes. But
their intimate structure, and the development of their spermatic particles
are so strikingly different, that this point alone would justify their separ-
ation from the Nematodes. (10)

§ H8.

With the exception of the Nematodes, and Gordiacei, the development of
all Helminthes, which reproduce by means of genital organs and eggs, is
metamorphotic. A complete series, from beginning to end of these meta-
morphoses has yet never been observed with any species. From the separate
parts of it here and there which have been observed, there appears the
remarkable fact, that the embryos after escaping the egg, are not always
changed at the end of the metamorphosis, into individuals like the parent, but
appear as larva-like animals, capable in their turn of producing other larvae.
These last larvae alone, change into individuals, which are like the parent.

This particular kind of transformation and development which is quite
common among the Trematodes, has received the name of Alternate Gene-
ration. (1) Whether it occurs among the Cestodes and Acanthocephali,
cannot now be stated positively, for as yet we are unacquainted with the
first period of their metamorphosis, — the embryo as it escapes from the
egg.(2) In many Cestodes and Trematodes, the embryos are developed
before the eggs are cast, and in some of the last order, they make their
escape while the eggs are in the uterus.

The development of the Cestodes occurs as follows : After the disap-
pearance of the germinative vesicle, large, transparent embryonic cells
appear in the midst of the vitellus, which undergoes fissuration. These
multiply by division, increasing at the expense of the vitellus, which in the

tightly to the vulva of the female in this act, that
they cannot disengage themselves ( Siebold and
Nathusius , in Wiegmann's Arch. 1836, 1. p. 105,
Taf. III. 1837, I. p. 60, 66). With many other
species of Strongylus, and Ascaris , it is not rare
to find a brownish gum about the vulva, and in
which there is, sometimes, the very distinct impress
of the male caudal valve (. Mehlis , Isis, 1831, p. 87).*

10 In the genus Mermis formed by Dujardin ,
the tubular uterus, the muscular vagina, and the
vulva situated far from the caudal extremity, — all
remind one much of the Nematodes. The eggs of
Mermis nigrescens , like those of Ascaris den-
tata , have long fibrillated appendages ( Dujardin
Ann. d. Sc. Nat. 1842, XVIII. p. 133, PI. VI., and
Siebold , in Wiegmann's Arch. 1843, II. p. 309) $
and at the caudal extremity of the males of Mermis
albicans, mihi (Entom. Zeit. 1843, p. 79), there
are, as in most Nematodes, two horny penises.

But with Gordius, the structure of the genital
organs is very different (see Siebold, and Dujar-
din, loc. cit.). In both sexes the cavity of the
body is completely filled with a double genital
tube, straight, and simple posteriorly, the sides
of which aie formed of large cells. The genital

* [ § 117, note 9.] For many details of the re-
productive organs of Ascaris infecta , with beauti-
ful illustrative figures, see Leidy, A Flora and
Fauna, &c., loc. cit. 4 B. PI. VII. 14, 16, b. 19. —
Ed.

t [ § 118, note 2.] The view here suggested of

opening is always at the posterior extremity of the
body. The testicular tubes of Gordius aquations
.contain anteriorly, cell-like bodies ; but posteriorly
there are others, staff-like, and which, being found
among the eggs in the uterine tube, I have regarded
as perfect spermatic particles. The genital open-
ing of the male Gordius is between the two more
or less prominent lobes of the caudal extremity,
and is without copulatory organs. The simple,
round, colorless eggs, are bound together at the
posterior part of the uterus by an albuminous sub-
stance, and are deposited in a very long row. It
is this row of eggs which Lion Dufour has
described as Filaria Jilariae (Ann. d. Sc. Nat.
XIV. 1828, p. 222, PL XII. fig. 4).

1 See Steenstrup, Ueber den Generationswech-
sel, &c., 1842.

v In various marine fish there is a trematode
larva of a Tetrarhynchus (Miescher, Bericut
ueber die Verhandl. d. Naturforsch. Gesellsch. in
Basel. 1840, p. 29, and in Wiegmann1 s Arch
1841, II. p. 302), which would lead one to con-
clude that alternate generation exists also with the
Cestodes.t ,

the alternating generation of the Cestodes, has
recently been confirmed most thoroughly by Sie-
bold, who has treated the subject in a most com-
prehensive manner, in a Memoir in Siebold and
Kblli/ceFs Zeitsch. II. 1850, p. 198. — Ed.

§118.

THE IIELMINTHES.

129

end they completely replace. When this has taken place, there is a mass
of extremely small cells, which, being covered with a delicate epithelium,
form a round or oval embryo, upon one extremity of which there are grad-
ually formed six small horny hooks. <S)

The embryos of the Acanthocephali are perhaps developed in the same
manner, but they have only four hooks. (4)

The Trematodes are developed exactly like the Cestodes, excepting that
their oval embryos have usually ciliated epithelium, and there is an oral
sucker in place of the hooks. (5)

Beside this first period of development, or embryonic state, there are
other more advanced or larval states, during which many Helminthes
have been described and figured as separate species in the science.*6'
Among these may be especially noticed two forms of the Trematodes — the
cylindrical and the cercarian larvae. The first (the germinative tubes of
Baer), form one of the phases of the alternate generation, and have a more
or less complete organization. In the cavity of their body, germinative
corpuscles are formed ; these consist of a vesicular, granular substance,
and resemble eggs neither by their structure nor mode of development.

These corpuscles produce larvae of a cylindrical or cercarian form, which,
deprived of their tail, are changed into perfect animals which have genital
organs; and thus the series of metamorphoses is terminated. <7)

3 For the embryonic development of Bothrioce-
phalus , and Taenia , see Siebold ( Burdach's
Phys. loc. cit. p. 200), Dujardin (Ann. d. Sc.
Nat. X. 1838, p. 29, PI. I. fig. 10, also XX. 1843,
p. 341, Pl. XV., and his Hist. d. Helm. PI. IX.-
XII.), and Kolliker ( Muller's Arch. 1843, p. 91,
Taf. VII. fig. 44-56).

The small hooks which the cestoid embryos so
actively protrude and retract, somewhat resemble
those which are circularly arranged with the adult
Taenia *

4 As yet, with Echinorhynchus gigas alone
have I succeeded in liberating the embryos from
the egg by compression. The four hooks of these
embryos resemble, by their form and position, those
of the Cestoid embryos. It does not appear, how-
ever, that the embryos of all Echinorhynchus
have them ; at least Dujardin has not found them
with those of Echinorhynchus transversus , and
globocaudatus (Hist. d. Helm. PI. VII.).

5 For the embryonic development of Monosto-

mum , and Distomum , see Siebold ( Burdach's
Phys. loc. cit. p. 206), and Kolliker (Muller's
Arch. loc. cit. p. 99). The embryos which swim
about like Infusoria by means of ciliated epithelium,
and which escape the egg while yet in the uterus,
have been observed of Distomum hians , by Meh-
lis (Isis 1831, p. 190) ; of Distomum nodulosum
and globiporum , by Nordmann and Creplin
(Microgr. Beitr. Hft. 2, 139, and in Ersch and

Gruber's Encyclop. XXIX. 1837, p. 324) j of
Distomum cygnoides , longicolle , Amphisto-
mum subclavatum , and Monostomum mutabile ,
by mj'self (Wiegmann's Arch. 1835, I. p. 66, Taf.
I.). See also Dujardin , in the Ann. d. Sc. Nat.
VIII. 1837, p. 303, PI. IX. fig. 3. I have seen the
embryos of Distomum tereticolle , and Aspido-
gaster conchicola , without the ciliated epithelium.

* f § 118, note 3.] The history of all our best
embryological studies shows that the segmentation
of the vitellus is the invariable preface to the be-
ginning of development with all true ova. In the
case of the Cestodes, if, as above mentioned, there
is no such process, it is highly probable that such

Those of Distomum. longicolle , cygnoides , Mon-
ostomum mutabile , and Aspidogaster conchi-
cola:, have an oral sucker. In this last species,
there is another sucker also, at the posterior ex-
tremity of the body ( Dujardin , Hist. d. Helm. p.
325).

6 In this category are the genera Cercaria ,
Histrionella , Bucephalus and others, which as
yet have been founded only upon different species
of Trematode larvae. The Helminth described by
Leblond (Ann. d. Sc. Nat. VI. 1836, p. 289, PI.
XVI. fig. 3) as Ampliistomum ropalo'ides , is only
a larva of a Tetrarhynchus. The species forming
the genus Scolex are certainly only imperfect
Bothriocephalus ; and the Gryporhynchus pu-
si.llus of Nordmann (Micr. Beitr. Hft. I. p. 101,
Taf. VIII. fig. 6, 7), is probably only a young
Taenia. There may also be a doubt here, if the
Cystici can be considered as real species.

It is very probable that they are imperfect Ces-
todes whose genital organs are to be afterwards
developed, as with Cysticercus fasciolatus, while
the Rodents in which it lives are devoured by car-
nivorous animals. Taenia crassicollis is, per-
haps, to Cysticercus fasciolar is, what Bothrioce-
phalus nodosus is to Bothriocephalus solidus-,
see Creplin, Nov. Observ. &c. p. 90.

7 The cylindric larvae of the Trematodes have
been termed by St eenstr up (loc. cit. p. 50) nurses
(Ammen). They are yet known only as living
parasitically upon Mollusks, as for instance, upon
Paludina, Lymnaeus, Planorbis, Ancylus, Suc-
cinea, Anodonta, and XJnio ; also upon Helix
pomatia, and Tellina baltica, according to Boja-
nus, Baer , Carus, Steenstrup, and n^'self. The
cylindric larvae of Bucephalus polymorphic, are
very long tubes, varicose here and there, some-
times ramified, and which do not exhibit any

development is not from true eggs but rather from
buds, a view which is the more worthy of attention
from the recent developments made by Siebold
with Gyrodactylus ; see below, my note under
§ 118, note 7. — Ed.

130

THE HELMINTHES.

§ 119.

«

§ 119.

With the Nematodes, of which very many are viviparous, the embryos

are developed within the egg in two

movements ( Baer , in the Nov. Act. Acad. Leop.
XIII. pt. 2, p. 570, Tab. XXX.). Those of Dis-
tomum duplication have simple, oval, and rigid
germinative utricles (Baer, Ibid. p. 558, Tab.
XXIX.). Those of Cercaria ephemera , are also
very simple, but of a cylindrical form ( Siebold , in
Burdocks Phys. loc. cit. p. 187, and Steenstrup ,
loc. cit. p. 78, Taf. III. fig. 1-6). Those of Cer-
caria furcata are simple and cylindrical, but very
long and endowed with quite active peristaltic
motions (Baer, loc. cit. p. 626, Tab. XXXI. tig. 6).
The curious animal, Leucochloridium paradox-
um , consisting of only a cylindrical sac with a
tail, is only a trematode larva (Carus, in the Nov. *
A^ct. Acad. Leop. XVII. pt. 1, p. 85, Tab. VII.).

\V ith the slow-moving, cylindrical, orange-colored
nurses of Cercaria ephemera, there may be easily
seen a mouth, a pharynx, and a simple coecal
intestine (Siebold, in Burdock's Phys. loc. cit. p.
187). Those of Cercaria echinata, are similar,
but they have also two short oblique prolongations
in front of the obtuse caudal extremity (Baer, loc.
cit. p. 629, Tab. 31, fig. 7, and Steenstrup, loc. cit.,
p. 51, Taf. II. fig. 2-4). The germinative bodies
from which Cercaria is developed, have nothing
comparable to a chorion or germinative vesicle.
Their larvae have always a tail, which is simple
(Cercaria armata, ephemera, Distomum dupli-
catum ), or bifurcated (Cercaria furcata ), or
double (Bucephalus polymorphus). The move-
ments of this tail are very slow with Distomum
duplicatum, but extremely lively and vortical
with Cercaria. With Bucephalus, the two fili-
form tails lengthen and shorten considerably, at the
same time jerking all about.

When the larvae are developed, they leave the
corpuscles and pass into other animals to complete
their final metamorphoses. Many Cercariae appear
to prefer the larvae of insects whose bodies they en-
ter by means of their cephalic hooks. In this way
I have seen the Cercaria armata easily enter the
larvae of Ephemera, Nemura , and Perla. By the
aid'of its sting it can perceive the intersegmental
membrane of these larvae. Frequently it loses its
tail in passing through a narrow opening it has
made.

Immediately upon reaching the cavity of the
body of the larva, it is surrounded by a vesicular
membrane, in which the sting is rejected, and the
animal enters upon its final metamorphosis. But
I have a doubt whether it is there completed, for
among the numerous similar parasites which I have
found in the most different insects whose larvae are

* [§ 118, note 7.] In this connection should be
noticed the remarkable phenomena of reproduction
with Gyrodactylus as recently observed by Sie-
bold (Siebold and Kolliker's Zeitsch. I. 1849, p.
345). Individuals are here developed viviparously
as in the so-called alternating generations, and
Siebold has observed a mother in which was a
daughter and in this last a grand-daughter, the
series being therefore three-fold. These viviparous
individuals contain no sexual organs proper, but
the new individual is developed out of a group of
cells situated within the body. The whole repro-
ductive conditions which Siebold has detailed with
his usual care appear to me to closely resemble
those of the viviparous Aphides which I have

different ways : Either the embryo-

aquatic, as of Libellula. Agrion, Ephemera, and
Phryganea, I have never met with one whose
genital organs were in a state of advanced develop-
ment.

The full development of these organs, the deli-
cate contours of which may be seen while the par-
asites are in the bodies of these animals, is not
perhaps attained, until the insects have been
swallowed by birds and other animals, — being
thereby furnished with more proper conditions for
their complete formation.

Some Cercariae lose their tail and are surrounded
with a capsule without leaving the Mollusks which
are their first habitat. This is probably so, be-
cause these Mollusks are liable to be eaten by
aquatic birds, in which these parasites may prop-
erly reach their final development. It should,
however, be remarked that when these larvae be-
come chrysalides, their investing capsule or cyst,
is a secretion from their bodies, and not a product
of the animals in which they live. It is probable
that very many of these larvae never attain a per-
fect state, for, in their migrations, they fail to reach
their destined and final habitat.

These migrations undoubtedly occur with many
Cestodes while young •, at least Mi esc her (loc. cit.)
has observed it with Tetrarhynchus. But although
we have followed these in their migrations, and the
transformation of many of them into Monostomum
and Distomum has been observed, and therefore
the completion of their metamorphoses, yet we are
but slightly informed as to their beginning by the
alternation of generation.

There is yet little known as to the manner in
which these embryos are changed into the cylin-
dric nurses. There are now only two isolated facts
throwing light upon this point. According to my
own observations (Wiegmann's Arch. 1835, I.
p. 75, Taf. I.), each embryo of Monostomum
mutabile contains a germinative tube, which, at
the death of the embryo, is freed and quite resem-
bles the nurse of Cercaria echinata. I have also
observed in the embryos of Amphistomum sub-
clavatum a tubular body, but I could not satisfy
myself of its germinative nature. According to
Steenstrup (loc. cit. p. 98), there is an animal like
a Paramaecium, and probably an embryo of a
Distomum , living in Muscles, and which finally
is deprived of its epithelium, and changed into the
rigid, germinative tube of Distomum duplicatum ;
see upon this, my Jahresbericht in Wiegmann's
Arch. 1843, II. p. 300.*

recently investigated •, and I believe this mode of
reproduction to be only a peculiar form of gemmi-
parity or budding suited to some ulterior, econom-
ical purpose of the animal’s life. On a future page
I shall speak more fully on this point and attempt
to show that the whole set of phenomena known
under the name of “ Alternation of Generations n
is, when divested of its paraphernalia, only a kind
of Gemmiparity.

See also for further details on that curious ani-
mal Leucochloridium paradoxum , Piper, in
Wiegmann's Arch. 1851, I. p. 313, but especially
Siebold , in Siebold and Kolliker's Zeitsch. IV.
1853, p. 425, Taf. XVI. B. This last-named ob-
server has shown that this animal form is only a

§ 119.

THE HELMINTHES.

131

nic cells present the same successive phases as in the Cestodes and Trema-
todes, without the appropriated vitellus undergoing any segmentation ; or,
the whole vitellus after a complete segmentation, is changed into an em-
bryo.®

In both cases, the embryo has the parent’s form. A muscular oesopha-
gus and straight intestine appear in its body in the midst of the refuse
vitelline granules; and thus the young animal attains its perfect state by
simple increase and by the development of its genital organs, but without
any metamorphosis.®

From the few observations hitherto made upon the development of the
Gordiacei, it appears that the embryos exactly resemble the parents.®

1 Kolliker was the first to call the attention to
these two types of development with the Nema-
todes ( Muller's Arch. 1843, p. 68, Taf. YI. VII.).
With Ascaris dentata , Oxyuris ambigua , and
Cucullanus elegans , free embryonic cells are
formed in the vitellus without its fissuration. But
there is a complete segmentation with Ascaris
nigrovenosa , acuminata , succisa , osculata ,
labiata , and brevicaudata , Strongylus auricu-
laris , dentatus , Filaria inflexo-caudata,rigida ,
and Sphaerularia bombi. After I had already
noticed this vitelline segmentation with the Ne-
matodes ( Burdock's Phys. loc. cit. p. 211), which
Bagge (Dissert, loc. cit.) described very fully,
Kolliker (loc. cit.) attempted to reconcile it with
the cell-theory, by regarding the cells which
appear in the segmented, vitelline globules, as the
embryonic cells, and in the multiplication of
which by segmentation, the enveloping vitellus
participates.

2 It appears that, as with the Trematodes, so in
the Nematodes, a migration of the young precedes
their complete development.

In the tissues of the most different insects and
vertebrates, there are found small Nematodes
without genital organs, and contained in a cyst.
They could not get there except by a migration,
and they cannot attain the full development of

kind of nurse of a Distomum , containing peculiar
germ-bodies which are developed into Distomum.
But the most important result obtained is that all
Distomum are not developed by means of a cer-
carian, larval stage, — the economy of some making
it seemingly requisite that the developmental pro-
cess should be more direct. — Ed.

* [ § 119, note 2.] In regard to Trichina spi-
ralis, the various researches upon its structure,
made in England and America, would show that it
is a true animal having genital organs. The fol-
lowing are some of the references upon this sub-
ject : Owen , London Med. Gaz. April and Decem-
ber, 1835, or Transact. Zool. Soc. London, IV., or
Cyclop. Anat. and Phys. Art. Entozoa ; Wood ,
London Med. Gaz. May, 1835 j Farre , Ibid. De-
cember, 1835 *, Harrison , Report of the Brit.
Assoc, for the Advancem. of Sc. 1835 ; Knox , Edinb.
Med. and Surg. Jour. 1836, XLVI. p. 86 Hodg-

their genital organs or their bodies in general,
except through a transplantation upon other ani-
mals 5 exactly as occurs with the trematodal larvae.
(See the observations of Creplin and myself upon
the sexless Trematodes, in Wiegmann's Arch.
1838, I. p. 302, 373.)

The Trichina spiralis of man is undoubtedly an
encysted and imperfect form of one of the Nema-
todes, and in which one may seek in vain for gen-
ital organs. Some of these Nematodes appear to
increase in their cysts without their genital organs
being developed in the same proportion. Thus, the
Filaria piscium are sometimes found very large,
while their genital organs are very little developed ;
and these last do not probably attain their perfect
state, until, as with Bothriocephalus solidus ,
these worms have passed into other animals. For
the same reason, I agree with Steenstrup (loc. cit.
p. 113), who doubts that the Filaria piscium
become, as Miescher has affirmed (loc. cit. p. 26),
a globular capsule out of which there afterward
appears an animal at first resembling a Trema-
tode, but which finally becomes a Tetrarhyn -
chus.*

3 S ee Du jar din (Ann. d. Sc. Nat. XVIII. loc.
cit. PI. VI. fig. 15, 16) upon Mermis nigrescens,
researches which I have been able thoroughly to
confirm.!

kin , Lect. on Morbid Anat. of Serous and Mucous
Membranes, I. p. 212 ; Curling , London Med.
Gaz. February, 1836 ; Bowditch, Boston Med. and
Surg. Jour. April, 1842 ; Luschka , Siebold and
Kolliker' s Zeitsch. III. 1851, p. 69, Taf. III., and
Gairdner , Edinb. Monthly Jour, of Sc. May,
1853. The subject is one that deserves especial
attention from Helminthologists. — Ed.

t [§ 119, note 3.] Grube (Wiegmann's Arch,
fur Naturgesch. 1849, p. 358) and Leidy (Proc.
Acad. Sc. Philad. V. 1850, p. 98) have observed
the development of Gordius. It corresponds
pretty closely with that of Ascaris as described by
Bagge ; but the embryo on escaping from the egg
is annulose and tentaculated, and differs much
from the adult form. Nothing is known of the
history of the animal between these two conditions.
— Ed.

BOOK SIXTH.

TUO ELL AM A.

CLASSIFICATION.

§120.

The Turbellaria receive their name from the ciliated epithelium, which
covers their whole body. Their flattened, or cylindrical, non-articulated
body, is formed of a loose parenchyma, in which lie hid the viscera. The
nervous system appears very little developed, and when visible, consists only
of a cervical ganglion, from which there never extends a ventral cord.
The multiramose intestinal canal is always without an anus. The genital
organs are either very much developed, or entirely absent.® In the first
case, these animals are always hermaphrodites, and have copulatory organs.

The Turbellaria have been shifted from one zoological system to another,
but their organization has sufficient peculiarities to entitle them to a special
class by themselves.

Ehrenberg was the first to found the group Turbellaria ; but he has in-
cluded therein many different animals ; and we are, therefore, indebted to
Orsted, for a late revision of this group.

ORDER I. RHABDOCOELI.

The alimentary canal is simple and cylindrical ; the oesophagus, non-
protractile; locomotion, mostly natatory.

Genera : Vortex, Derostomum , Gyratrix, Strongylostomum, Mesostomum,
Typhloplana, Macrostomuvi, Microstomum.

ORDER II. DENDROCOELI.

Intestinal canal dendritically ramified ; oesophagus completely protrac-
tile ; locomotion reptatory.

1 I cannot here omit the question, if these small era, and if they are not rather the larvae of other
sexless Turbellaria, as for example, Derostomum , inferior animals.

•and Microstomum , really constitute distinct gen-

§ 121. THE TURBELLARIA. 133

Genera : Polycelis, Monocelis, Planaria, Leptoplana , Eurylepta, Planoce-
ra, Thysanozoon.

BIBLIOGRAPHY.

Baer. Ueber Planarien, in the Not. Act. Acad. Leop. XIII. 1826,
p. 691.

Duges. Recherches sur ^organisation et les moeurs des Planariees, in
the Ann. d. Sc. Nat. XY. 1828, p. 139 ; and XXI. 1830, p. 72. See
Isis 1830, p. 169, or Froriep’s, Not. 1829, No. 501.

Mertens. Ueber den Bau verschiedener in der See lebender Planarien,
in the Mem. de l’Acad. de St. Petersbourg, 6eme Ser. Tom. II. 1833, p. 1.

Ehrenlerg. Phytozoa turbellaria, in the Symbolae physicae, Ser. I.
1831.

Foci re. Ueber Planaria Ehrenbergii. in the Ann. des Wiener Mus. I.
Abth. 2, 1836, p. 193.

F. F. Schulze. De Planariarum vivendi ratione et structura penitiori
nonnulla. _ Dissertatio. Berolini, 1836.

A. S. Orsted. Entwurf einer systematischen Eintheilung und speciel-
len Beschreibung der Plattwurmer. Copenhagen, 1844.

ADDITIONAL BIBLIOGRAPHY.

Beside the writings referred to in my notes, see the following :

Schmidt. Die rhabdocoelen Strudel wiirmer des siissen Wassers. Jena,
1848.

Neue Beitriige zur Naturgesch. der Wiirmer. Jena, 1848. Erster
Abschnitt, Turbellarien.

Handbuch d. vergleich. Anatomie, 1849, p. 294.

M. S. Schultze. Ueber die Microstomeen, eine Familie der Turbellarian,
in Wiegrnann's Arch. 1849, p. 280, Taf. VI.

Beitrage zur Naturgeschichte der Turbellarien. 1851. — Ed.

CHAPTER I.

CUTANEOUS SYSTEM.

§121.

The whole body of the Turbellaria is covered with ciliated epithelium,
under which lies a loose cellular parenchyma. In this parenchyma, and
directly beneath the epithelium, there are found, in many species, particu-
lar cell-like bodies, which sometimes remind one of the nettling organs of
certain zoophytes, and sometimes exactly resemble the prehensile organs
12

134

THE TURBELLARIA.

§ 122.

of the arms of Polyps. (,) These bodies contain six or eight, or even more,
staff-like, colorless corpuscles, which are parallelly arranged side by side,
or curved a little spirally. With their further development, the envelope
disappears, and they then remain free under the skin, but sometimes pro-
jecting through it.1 (2)

CHAPTER II.

MUSCULAR SYSTEM AND LOCOMOTIVE ORGANS.

§122.

Although their parenchyma is extremely contractile, yet the Turbellaria
have only a very feebly-developed muscular system.

In many small species of the Rhabdocoeli, the parenchymal muscles
may be made out ; and in the larger Planariae, when the muscles are visi-
ble, their fibres appear unstriated.

The small Rhabdocoeli swim by means of their ciliated epithelium, like
many Infusoria, their bodies revolving on its longitudinal axis ; while the
flattened Dendrocoeli crawl along like the Gasteropoda. a> Many larger
species of the first order,® appear to float from place to place by means of
their epithelium, thus really neither creeping nor swimming.

1 With Microstomum lineare , Orsted , these
prehensile organs so closely resemble those of
Hydra that they need not be described. According
to Orsted they are urn-shaped glands in the centre
of which are parabolic bodies which are constantly
in motion (loc. cit. p. 73, Taf. II. fig. 18). But
had he pressed these organs between two plates of
glass, he would have seen the protruding filament,
together with its double hooks.

2 I have seen these corpuscles protruding through
the lateral border of the body of Planaria lactea.
In the dorsal papillae of Thysanozoon Diesingii ,
a part of these corpuscles are contained in cells j
but the others are free and often protrude through
the skin. With Mesostomum Ehrenbergii , and
rostratum , they are arranged in rows in the
anterior half of the body, forming striae, which
quickly catch the attention. Orsted has taken
these corpuscles for as many muscular columns
(loc. cit. p. 70, Taf. II. fig. 26, 37). The spines
which, according to him (loc. cit. p. 72, Taf. II. fig.
29, 34) cover the entire surface of Macrostomum

hystrix , are probably of the same nature, as may
also be said of the delicate short bristles found
everywhere under the skin of Derostomum leu-
cops, Duges.

Quatrefages , in his monograph on marine
Planariae (Ann. d. Sc. Nat. IV. 1845, p. 146, PI.
VIII. fig. 9, 10), also mentions various formations
which, partly as spines, partly as nettling or-
gans, are found in the skin of certain Dendrocoeli.

1 The mode of locomotion by which these animals
move over solid bodies, or upon the surface of the
water, has not yet been satisfactorily explained.
The ciliated epithelium cannot here be the principal
agent. According to Schulze , loc. cit. p. 32, the
staff-like corpuscles projecting from the back of
these animals, and which he terms bristles, are used
as oars.

According to Mertens (M4m. de l’Acad. de St.
Petersbourg, 0eme, s£r. II. 1833, p. 5), Planaria
lichenoides moves by means of the protruded
lobes of its pharyngx.

2 For example, Mesostomum.

123, 124.

THE TUllBELLARIA.

135

CHAPTERS III. AND IV.

NERVOUS SYSTEM AND ORGANS OF SENSE.

§123.

The nervous system with the Turbellaria, is quite indistinct, for it has
not yet been observed in the small species, and in the larger ones its dis-
position is yet doubtful. A double ganglion in the cervical region appears
to form its central part, and from this nerves pass off in different direc-
tions.(1)

§ 124.

Among the organs of sense, those of vision are the most developed with
very many species.

The red, brown, or black spots on the anterior extremity, two or
more in number, are not always simple pigment cells, (]) but may be regard-
ed as eyes, for they have a cornea, — a light-refracting body surrounded
with pigment, and a nerve-bulb. (2)

As to the sense of touch, no special tactile organs have yet been found,
but the whole surface reacts sensitively from the lightest contact; and this
sensibility appears particularly prominent at the anterior extremity, which,
with many Dendrocoeli, is furnished with lobular and other appendages.®

1 Ehrenberg has seen two disconnected ganglia
with Planaria lactea (Abhand. d. Berl. Akad.
1835, p. 243). With other Dendrocoeli, as with
Planocerasargassicola,ai\d pellucida, these two
ganglia are blended into one 5 at least, the organ
which Mertens has here described as a heart, has
exactly the appearance of two united ganglia (loc.
cit. Taf. I. fig. 6, Taf. II. fig. 3, ra. or Isis 1836, Taf.
IX. fig. 3, c. m.). The light pulsations which this
author affirms to have here observed, are perhaps,
as Ehrenberg has supposed (loc. cit. p. 244), due to
the contractions of neighboring organs. According
to Schulze (loc. cit. p. 39), with Planaria torva ,
the double central ganglion gives off two nerves,
which pass backwards on both sides of the intes-
tine.

This double ganglion, situated in the cervical re-
gion, and the nervous filaments which it gives off,
have been demonstrated by Quatrefages (loc. cit.
p. 172, PI. IV .-VI.).

1 Most commonly there are two eye-dots. With
Planocera , and Leptoplana , there arc many which
are grouped together, and with Polycelis nigra ,
the whole anterior part of the body is covered with
them. In many small species, they appear to be
of a simple pigmentary nature.

2 With Planaria lactea , there is, between the
cornea-like bulging of the skitf, and a semilunar,
pigment layer, a small, conical, transparent body,
corresponding exactly to a crystalline lens j see
Ehrenberg , loc. cit. p. 243, and Schulze , loc. cit.

* [ § 124, note 2.] See also Leidy (Proc. Acad.
Nat. Sc. Philad. m. 1848, p. 248) on the eye-specks
of Phagocata gracilis , a sub-genus made by him
from Planaria , and Schmidt (Die Rhabdocoglen
Strudelwiirmer,&c., p. 7, and Neue Beitrilge Zur
Naturgesch, der Wiirmer, &c., p. 11). Both of
these observers agree in considering these parts in

p. 37. With Monocelis , these organs are very
remarkable, being composed of two eyes blended
into one, and the simple and spherical ball of the
eye is filled, according to Orsted , with a transpa-
rent vitreous body, in which two conical crystalline
lenses are buried with their apices pointing in-
wards (loc. cit. p. 6, 56, Taf. I. fig. 1, 2, and in
the text, fig. 10). Orsted has distinctly seen two
optic nerves passing laterally to this organ. It is
quite remarkable that with one of the three known
species, the Monocelis unipunctata , the eye is
entirely without pigment. Ehrenberg affirms that
he has observed with Polycelis , many star-like
ganglia in the middle of the anterior part of the
body, which are for the long row of eye-dots (loc.
cit. p. 243).

For the eyes of the marine Planaria*, see also
Quatrefages , loc. cit. p. 178, PI. III. The organ
which with Monocoelis has been taken for an eye
by Orsted , appears to be, according to the re-
searches of Frey and Leuckart (Beitr. p. 83, Taf.
I. fig. 18), an auditory organ. That which Orsted
regarded a vitreous body, is an otolite, and his two
crystalline lenses, are two semicircular prolonga-
tions attached loop-like to the otolite. Frey and
Leuckart are also convinced that Convoluta par-
ado xa- Orst ., has a single auditive capsule, situated
on the median line of the cervical region, and con-
taining an otolite which floats in a lilac-colored
fluid 5 see Beitr. loc. cit. p. 82, Taf. I. fig. 17.*

3 There are contractile and antenniform append-

question as visual organs. Schmidt has often
failed to find anything like an otolite 5 but, on the
other hand, has often found with various Derosto -
mum a complete visual apparatus. This point,
therefore, is still unsettled, unless, as Schmidt in-
geniously suggests, it may be that one organ serves
the functions of two separate senses. — Ed.

136

THE TURBELLARIA.

§ 125.

CHAPTER V.

DIGESTIVE APPARATUS.

§ 125.

With the two orders of Turbellaria, this apparatus is formed upon very
different types. But in both orders, the location of the mouth varies so much,
that it serves as the basis of genera, according as it is at the anterior extrem-
ity, or a il’ tie behind it, — or, at the middle of the belly, or a little behind
that also. The walls of the intestinal canal are always intimately blended
with the parenchyma of the body.

With the Rhabdocoeli, the mouth leads to a muscular oesophagus, which
is either an annular sphincter, or a longer or shorter tube, but which, in no
case, can be everted from the mouth. The intestinal canal is a simple cae-
cum extending from the oesophagus to the posterior extremity ; but with
those species which have the mouth situated more or less posteriorly, it
stretches forward as a coecum to the anterior portion of the body.® With
the Dendrocoeli the mouth opens into a large throat, containing a protrac-
tile and very movable deglutitory organ (Pharynx).

This organ, which can be protruded entirely out of the throat while the
animal is eating, is either a tube comppsed of longitudinal and transverse
muscles, or a collection of lobular and ramified tentacles circularly ar-
ranged about the mouth.

Its base is prolonged into the proper intestine, whose dendritic ramifi-
cations extend over the whole body.®

Scarcely a trace of salivary or hepatic organs have here been found
with these animals. (3)

ages on the anterior part of the body of Planaria
tentaculata , and Eurylepta cornuta , and upon
the neck of Planocera. With the last, they sup-
port a part of the eye dots.

1 The mouth and cylindrical oesophagus of Gy-
ratrix hennaphrodilus, and Vortex truncata , are
at the cephalic extremity ( Ehrenberg , Abhandl.
d. Bcrl. Akad. 1835, p. 178, Taf. I. fig/ 2, 3). But
the mouth and annular oesophagus of Derosto-
mum is situated just back of this extremity, into
which, however, the coecal intestine extends. The
oesophagus is also annular with Mesostomum ,
and Typhloplana. In the first, the mouth is at the
middle of the ventral surface ; and in the last, a
little behind this point, while the intestine projects
coecally far into the anterior extremity ( Orsted ,
loc. cit. Taf. II. fig. 26, 31, and Focke , loc. cit.
Taf. XVII.).

- The genus Planaria has become famous for its
movable organ of deglutition, which, being sepa-
rated from the body, still continues for a while to
swallow all presented to its mouth (Baer, loc. cit. p.

* [ § 125, note 2.] With Phagocata ( Planaria )
gracilis , Leidy (Proceed. Acad. Nat. Sc. Phil. in.
1848, p. 248) found, instead of a single sucker,
twenty-three, In the full-grown animal. These are
all protruded when the animal feeds, but when
not in use, are closely packed together within the
animal. They all connect separately with portions
of the dendritic alimentary cavity. — Ed.

716, Tab. XXXIII. fig. 8-11, and Duges, loc. cit.
XV. p. 152, PI. IV. fig. 18, 19).

The large and plicated oesophagus of Planaria
treme llaris, constitutes the transition to the ten-
tacular form of the deglutitory organs (Dugds, loc.
cit. XV. PI. IV. fig. 20, 21). Fully ramified ten-
tacles are found with Planocera sargassicola,
pellucida , and Leptoplana lichenoides. When
collected in the throat, they present exactly the as-
pect of a ramified intestine ( Mertens , loc. cit. Taf.
I. fig. 2, 3, 6, Taf. II. fig. 3, 4, and the Isis, 1836,
Taf. IX. fig. 3, b. 3, c.). The ramified intestine of
many Dendrocoeli has been figured by Baer, Du-
g£s, and Mertens , in their works already cited.*

3 Focke (loc. cit. p. 196, Taf. XVII. fig. 11, c.
f.) is inclined to regard as salivary and hepatic or-
gans, two large lateral vessels, and a glandular or-
gan which he has discovered near the oesophagus
and intestine of Mesostomum Ehrenbergii ) but
he himself admits that this view is not yet well
founded, t

t [ § 125, note 3.] Will (Muller's Arch. 1848,
p. 508) has shown that the brownish layer covering
the whole extent of the intestine of Planaria is
composed of hepatic glands (Dendrocoalum lac-
teum , Planaria torva , and nigra). — Ed.

$126.

THE TURBELLA RIA.

137

CHAPTERS VI. AND VII.

CIRCULATORY AND RESPIRATORY SYSTEMS.

§126.

As yet, only a very imperfect vascular system has been observed in the
parenchyma of these animals. With the Dendrocoeli, there are constantly
two principal vessels, extending along each side of the body, which give
off many lateral branches and anastomose together at their two extremi-
ties.

This system has no central heart-like organ, and the walls of the vessels
not being contractile, the circulation is probably effected through the gen-
eral contractions of the body.(1) The contained homogeneous and colorless
liquid ought therefore to be considered as a nutritive fluid.

With the Rhabdocoeli, the disposition is different. In many there are
one or two vessels which traverse the body and loop at its extremities,
without either giving off branches or diminishing in size. The movement
of their colorless liquid is due to isolated vibratile lobules situated here and
there in the vessels.

This organization reminds one more of an aquiferous than a sanguineous
system.®

Special respiratory organs are here wholly absent, if we do not regard as
such the aquiferous system just mentioned. There remains, therefore, only the
conjecture that the ciliary epithelium upon the entire surface of the body is
subservient to a general cutaneous respiration, by constantly bringing the
water in contact with the skin.

1 Dugis has described and figured very com-
pletely the vascular system of Planaria (loc. cit.

XV. p 160, PL V. fig. 1, 2, XXI. p. 85, PI. H. fig.

24, 25). The cordiform organ which Mertens (loc.
cit. p. 12, Taf. I. fig. 6, Taf. II. fig. 3) refers to the
vascular system of Planocera sargassicola and
pelfucida, is probably, as seen above, the central
part of the nervous system. Dug Us is the only
observer who affirms to have seen with the Den-
drocogli proper movements of the vessels *, while
Mertens , Ehrenberg (Abhandl. d. Berl. Akad.
loc. cit. p. 243), Schulze (loc. cit. p. 18), and Ors-
ted (loc. cit. p. 16), have observed only the con-
trary.

2 With Derostomum leucops , Dug., I have
seen two intertwined vessels of equal size through-
out, extending from the caudal extremity to the
head where they form a simple loop. At the cau-

* [ § 126, note 2.] See for these two systems, Neue Beitr. zur Naturgesch. d. Wiirmer, &c.,
Schmidt , Die Rhabdoc, Strudelw. &c., p. 11, and p. 15. — Ed.

12*

dal extremity, they approach so near to the cuta-
neous surface that it is impossible to decide whether
they terminate there by a loop, or open externally.
Ehrenberg (Abhandl. d. Berl. Akad. loc. cit. p.
178, Taf. I. fig. 2) has figured two pairs of such
vessels with Gyratrix hermaphroditus , and which
loop at the posterior extremity, but in front termi-
nate indistinctly. The trembling in the interior of
these vessels observed by Ehrenberg , indicates
certainly the presence of vibratile lobules, and
which Orsted (loc. cit. p. 17, Taf. III. fig. 48) has
distinctly found in the vessels of Mesostomum
Ehrenbergii , while Foclce (loc. cit. p. 200) could
see only their effects. These are the very vessels
which this author supposes connect with the pha-
rynx •, but this is not so according to my own ob-
servations.*

138

THE TURBELLARIA.

$§ 127, 128.

CHAPTER Y 1 1 1.

ORGANS OF SECRETION.

§ 127.

No special organs of secretion have yet been found with the Turbellaria,
although these animals, and especially the Dendrocoeli, secrete from their
cutaneous surface an extraordinary quantity of mucus. (1)

CHAPTER IX.

ORGANS OF GENERATION.

§ 128.

The Turbellaria propagate by transverse fissuration, and by the means
of genital organs.

In the smaller Rhabdocoeli, which have no trace of genital organs, the
transverse fissuration is the rule.(1> It is, however, probable that at cer-
tain epochs of their lives, genital organs are developed, and therefore, that
they multiply also by eggs.®

With both the larger Rhabdocoeli, and the Dendrocoeli, the genital and
copulatory organs of both sexes are situated upon one and the same individual,
so that they are capable of self-impregnation ; but there is generally a re-
ciprocal copulation.® This genital apparatus is very complex, and as the
contents of its various parts have not yet been subjected to a careful analy-
sis, it is not positively certain that the right interpretation of them is
given.

1 It is yet undecided whether the subcutaneous
cell-like bodies of the Dendrocofcli have any relation
to this secretion.

1 Duges (Ann. d. Sc. Nat. XV. p. 169, PI. V. fig.

15) has observed a voluntary transverse fissuration
with Derostomum leucops. I have been able to
follow the very regular fissuration of Microsto-
mum lineare , where each unseparated half of the
body began to halve again, and then these four pieces
also each divided, and so finally the body appeared
worked by seven transverse furrows, into eight
divisions.

I must here remark, to prevent an error, that I,
contrary to Orsted (loc. cit. p. 73), regard these
two mentioned species as distinct 5 for Derosto-
mum leucops , Dug., is without the reddish brown
eye-dots and the prehensile organs, which are found
with Microstomum lineare, Orst. The wonder-
ful reproductive power of the sexless Planariae,

* [ § 128, note 1.] See Lcidy (loc. cit.) 5 he
found that with Phagocata ( ' Planar ia ) gracilis ,

and which can be multiplied artificially by divisions
in all directions, would lead us to infer that they
propagate also from accidental divisions, to which
their vulnerable nature is constantly exposed.*

2 Orsted (loc. cit. p. 21, Taf. III. fig. 53) and
Ehrenberg (Abhandl. d. Berl. Akad. loc. cit. p.
178, Taf. I. fig. 2, 3) affirm to have seen ovaries,
testicles, copulatory organs, and eggs with Micro-
stomum lineare , and many other allied Rhabdo-
co&i, such as Gyratrix, Vortex, and Strongylo-
stomum ; but the details they have given are too
Imperfect to allow definite opinions upon this or-
ganization. I must here ask if these animals have
not been confounded with the sexless larvae which
multiply by fissuration like those of Medusae.

3 Coition has often been observed with Planaria
and Mesostomum, and has been figured by Baer ,
Dugis, and Focke.

this subdivision could not be carried successfully
beyond three or four parts. — Ed.

$ 129.

THE TURBELLARIA.

139

The following are the parts usually found : an ovary or organ of vitel-
line secretion, which is double, and, extending into the parenchyma of the
body, opens by a common excretory duct into a large cavity, — a vagina or
oviduct ; a double testicle sends its seminal liquid, full of filamentoid and
motionless spermatic particles, into the seminal vesicle through two tor-
tuous vasa deferentia ; to this seminal vesicle is attached a very erectile
penis, situated by the side of the vagina. There is a common genital open-
ing, situated always behind the mouth, for the protrusion of this penis and
the escape of the eggs.

With Planaria, there are, beside, two special, hollow organs, with narrow
excretory ducts, which open into the vagina. Of these, one very probably
secretes the envelope of the egg, while the other serves as a Receptaculum.
seminis .(4)

§ 129.

The embryonic development of the Turbellaria is yet unknown except
with the Planariae.

It differs wholly from anything yet known with other Invertebrates.
Many of these embryos are developed, always simultaneously, in one
large egg; but it is impossible at first to determine their number, since

4 See, for the genital organs of Mesostomum Eh-
renbergii , Focke (loc. cit.)’, for those of Plano-
cera, and Leptoplana , Mertens (loc. cit.); and for
those of Derostomum, and Planaria , Dug is ,
Baer , and Orsted (loc. cit.). But the interpretation
here given of the different parts of these organs
must be much changed. For, to speak here only
of the genus Planaria , what Baer has regarded
as the ovaries and oviducts, are certainly the two
testicles with their vasa deferentia, since I have
always found them filled with spermatic particles
(loc. cit. Tab. XXIII. fig. 18, a. b.). The two sem-
inal canals open into a hollow, flask-shaped body
like a Vesicula seminalis or a Ductus ejacu-
latorius , the neck of which is continuous with a
very contractile and erectile tube (Penis). This
penis is in a cavity separated by a septum from
the large vulva, with which, however, it communi-
cates by a special orifice, and consequently can be
protracted through the common genital opening.
There is, beside the intestinal canal, another rami-
fied organ in the body of Planaria , and which
very probably is an ovary, or at least a vitellus-
secreting organ. But its caeca contain only simple
vesicular bodies, which have no germinative vesi-
cles. The canal which Dugis (loc. cit. XV. PI. V.
fig. 4, b.) has taken for an oviduct, belongs prob-
ably to the ramifications of this organ. The other
two organs which this author (Ibid. PI. V. fig. 4,
8, c.) has described as Visicule copul.atrice ou
reservoir du sperme et des oeufs , do not appear
to me to exist in all Planariae. ^hey consist of two
hollow, pyriform organs, not blended together as
Dugis has figured them, but distinct ; one opens
by a long, and the other by a shorter canal, into

* [ § 128, note 4.] See, for many details on the
sexual organs of the Turbellaria, and illustrated
with figures, Schmidt , loc. cit. (Protostomum,
Vortex , Hypostomum, Derostomum , Meso-
stomum, Opistomum, Macrostomum, Microsto-
mum , Stenostomum , Schizostomum , Typhlo-
plana ; according to this author, Dinophilus vor-
ticoides is separate-sexed, — the exceptional in-
stance among the Rhabdocoeli. The subject of the

the vulva. As I have found many spermatic par-
ticles in the first of these, I am led to regard it as
a Receptaculum seminis. But in the other,
which Baer (loc. cit. Tab. XXXIII. fig. 18, e.) has
taken for a penis, I have never found either eggs
or germs, but always only a granular substance ;
from this I am inclined to think that this organ se-
cretes the material which envelops the vitelline
cells grouped in the vulva. With the Planariae,
one egg at a time is always formed in the round
vagina ; this is very large, and when it is de-
posited others succeed it in the same way. This is
not true, however, with Mesostomum Ehren-
bergii ; here the vagina is short and narrow,
and receives various organs whose nature is
not yet well determined. One of these contains,
according to my own researches, a confused mass
of active, filamentoid spermatic particles, and may
therefore be regarded as a Receptaculum sem-
inis. Two canals which pass off right and left
from the vagina, bifurcate into two simple coeca,
one of which passes forwards, and the other back-
wards, and in which very large eggs remain for a
long time. This therefore may be regarded as an
uterus. See Focke , Taf. XVII. fig. 1, 11, g. g.

According to the very minute researches of
Quatrefages (loc. cit. p. 163, PI. IV.-VIII.) made
upon various marine Planariae, both the male and
the female organs of these DendrocoSli have two
distinct orifices situated in the ventral region, one
behind the other. The posterior is a vulva and
opens into a more or less long coecum (vagina or
copulatory pouch) upon which are laterally inserted
two oviducts. The anterior orifice is for the pro-
trusion of the protractile penis.*

spermatic particles of the Planariae is littleunder-
stood. They probably have not a hair-like form as
mentioned in the preceding note, but are Cercaria-
like ; see Kdlliker , loc. cit., Quatrefages, loc. cit.
PI. VIII. fig. 5-9, and Schmidt , Die Rhabdoc.
Strudelw firmer, &c., p. 16 ; this author, however,
describes those of Opistomum pallidum as some-
what different, there being a filament beyond the
head (Taf. V. fig. 14b). — Ed.

r

140

THE TURBELLARIA.

§ 129.

their chorion contains only loosely-arranged vitelline cells, among which
there is seen no trace of one or more germinative vesicles. The vitelline
cells always contain, beside a finely-granular albuminous substance, a round
nucleus which has a nucleolus. Both the nucleus and the granular sub-
stance are shifted from one side to the other of the cell by the very re-
markable peristaltic movements of the cell-membrane. After a time, these
movements cease, the cell-membrane disappears, and the contents mix with
those of other cells which have been affected in the same way : by these
means, little collections of vitelline substance here and there are formed,
which increase by the addition of other cells, — and finally are transformed
into roundish, nicely-defined embryos which become covered with ciliated
epithelium. From this time the embryos do not increase as before by the
external fusion of cells, but there is a muscular, discoid oesophagus formed
upon their periphery, and through this the remaining cells are ingested and
assimilated within the animal.

Still later, the embryo, hitherto spherical, becomes flat and elongated at
two opposite points ; — ultimately, and upon the appearance of the eye-
specks, it assumes exactly the form of the adult Planariae.

The size of the young Planariae depends upon the number of embryos
developed in the same egg, for the smaller this number, the larger the
embryos at the time of their hatching, and vice versa.

The cause regulating the number of embryos in an egg is yet un-
known.* (1>

1 See my details upon this subject in the Bericht.
ueber die Verhandl. d. Berl. Akad. 1841, p. 83.
During the development of Planar ia , one can,
after a while, ascertain the number of vitelline cells
assimilated by fusion and deglutition, by counting
their nuclei which are easily seen in the parenchy-
ma of the body. According to Focke (loc. cit. p.
201), the eye-specks, and the oesophagus are de-
veloped very early in the young Mesostomum
Ehrenbergii ; — a species with which each egg
contains a single embryo only, and which is devel-
oped while the egg is in the uterus.

* [ End of § 129.] Recent embryological studies
have thrown some light upon this point — the
alleged plurality of embryos in a single egg. The
so-called egg in these cases is almost undoubtedly
an ovarian sac. iu which are developed many germs-,
some of these germs may perish, and the fewness
of those remaining would give the appearance of
an egg with many germs. — Ed.

f [ § 129, note l.J The development of Plana -
ria has been also observed by Schmidt. Die Rhab-

The remarkable movements of the vitelline cells
in the eggs of the Planariae , and which I was the
first to observe, have since been confirmed by Kdl-
liker , with Planaria lactea ; see Wiesmann's
Arch. 1846, I. p. 291, Taf. X. I am unable to say
whether or not the spontaneous movements observed
by Quatrefages (loc. cit. p. 169, PI. VII. fig. 6-9)
upon the larger portions of the vitellus of Polycelis
pallidus while in the oviducts, are of the same na-
ture this naturalist himself supposes that these
portions were the embryos of this Planaria .f

doc. Strudelwiirmer, &c., p. 1Y-, by Agassiz (Proc.
Amer. Assoc. Advancem. of Sc. 2nd meeting, 1849,
p. 438), who made the interesting observation that
the Infusoria-genera, Kolpoda and Paramaeciumt
are only larvse of Planaria ; by Girard (Ibid. p.
398), and by Muller ( Muller's Arch. 1850, p.
485). Muller has here some interesting remarks on
the relations of the study of these forms to the
class Infusoria. — Ed.

$ 130.

THE ROTATORIA.

141

BOOK SEVENTH.

ROTATORIA.

CLASSIFICATION.

§ 130.

I The body of the Rotatoria is covered with a smooth, hard epidermis,
and, from transverse incisions* at least at its posterior portion, usually ap-
pears articulated ; while its anterior portion has vibratory retractile parts —
the so-called rotatory organs. The very indistinct nervous system is almost
wholly comprised in a cervical ganglionic mass. The fully-developed digest-
ive canal lies in the large cavity of the body, and its anterior portion is
provided with masticatory organs, while posteriorly, it terminates in an
anus. Female genital organs alone have as yet been found with certainty.

No one would deny that the Rotatoria, whose organization is so high,
ought to be separated from the Infusoria, whose stricture is scarcely advanced
above that of a simple cell-nature. One can be in doubt only as to their
other and proper place in the animal kingdom ; — whether, with Burmeister,
they are to be placed among the Crustacea ; or with Wiegmann, Wagner ,
Milne Edwards , Berthold , and others, among the Worms. Rut the choice
here between these two classes will not be difficult, for, as will soon be shown,
they differ widely from the Crustacea. Aside from the absence of a ven-
tral cord and of striated muscular fibres, these animals have vibratile or-
gans upon the surface of their body, as well as upon their respiratory and
digestive organs — a structure not found with the Crustacea, nor with the
Arthropoda in general.’ Their development is non-metamorphotic, and
they do not have articulated feet when they escape from the egg ; while
the Crustacea, and even those which, from a retrograde metamorphosis, be-
come vermiform, have at least three pairs of articulated legs when hatched.
On the other hand, they have, in common with most worms, an articulated
body, internal and external vibratile organs, absence of a ventral cord,
and, with all, the want of articulated feet.

Although the uniformity of their organization does not admit of these
animals being divided into orders, they can at least be considered as a sep-
arate class in the great section of Worms.

142

THE ROTATORIA.

$ 131.

Family : Monotrocha.

Genera : Ptygura, Ichtkydium, Chaetonotus, Oecistes, Conochilus.
Family : Schizotrocha.

Genera : Megalotrocha, Tubicolaria , Stephanoceros, Lacinularia, Melicerta,

F loscularia.

Family : Polytrocha.

Genera : Enteroplea, Pleurotrocha , Hydatina, Notommata, Synchaeta,
Polyarthra , Diglena, Triarthra, Eosphora, Cycloglena, Theorus, Masti-
gocerca, Eucklanis, Salpina, Stepha?iops, Squamella.

Family : Zygotrocha.

Genera : Rotifer , Actinurns, Philodina, Noteus, Anuraea, Brachionus.

BIBLIOGRAPHY.

See the works already cited under Infusoria.

ADDITIONAL BIBLIOGRAPHY.

Besides the writings of Brightwell, Huxley, Leydig, and others, quoted
in my notes, see the following :

O. Schmidt. Yersuch einer Darstellung der Organisation der Itader-
thiere, in Wicgmann's Arch. 1846.

Frey. Ueber die Bedeckungen der wirbellosen Thiere. Gottingen,
1848.

D'Udehem. Bull, de ’1 ’Acad. Boy. des Sc. de Belgique, XVIII. 1,
1851.

See also the new edition of Pritchard's Infusoria, given under Book
first. — Ed.

CHAPTER I.

CUTANEOUS SYSTEM.

§131.

Nearly all the Rotatoria are covered with a smooth, hard skin,a> which
is thrown into folds by the contractions of the subcutaneous parenchyma ;
at the anterior extremity only, it is very delicate, and covered with vibra-
tile organs, which also move to and fro with the parenchyma. With many,

1 With Chaetonotus , and Philodina aculeata ,
the structure of the skin is quite different from
this ; for its surface bristles with stiff points and

spines. With Noteus, and Anuraea , there are
species whose faceted skin is roughened by innumer-
able granulations.

THE ROTATORIA.

143

§§ 132, 133.

the annular sulcations of the skin, partial, or over its whole extent, give
the body an articulated aspect.® Many others have a skin so hard and
Btifij as to be like a carapace.®

CHAPTER II.

MUSCULAR SYSTEM AND LOCOMOTIVE ORGANS.

§132.

The muscular system of the Rotatoria is quite distinct in many parts of
the body. There can at once be observed, distinctly separated from the
general parenchyma, unstriated muscles, of which some are transversely
annular, and many others narrow and longitudinal. (1) The first, subcuta-
neous and widely separated from each other, are usually upon the borders
of the segments of the body. The second, divisible into dorsal, ventral and
lateral portions, arise from the internal surface of the skin, and are inserted
at the cephalic or opposite extremity.®

The posterior extremity of those species which move freely, has two stiff
points of variable length, which are moved as tentacles by two cylindrical,
or clavate, caudal muscles. Some have long, movable bristles or pedicles,
by which they row along or move by quick leaps.®

§ 133.

The prominent characteristic of the Rotatoria is the retractile, vibratile
apparatus at their cephalic extremity, known as the rotatory organs. By
these, they swim freely about, revolving upon their axis, or, when at rest,
produce vortex-like motions of the water. The form, number, and arrange-
ment of these organs varies much according to the genera, and may bo
used even to characterize families. \

The rotatory organ is either single, double, or multiple. Often it con-
sists of a disc, supported by a pedicle of variable length, upon whose bor-
ders are successive rows of regularly-arranged cilia, the motion of which
gives the appearance of rotation to the disc itself. This apparent motion

2 With Conochilus , Megalotrocha , Lac inula -
n'a, Brachionus , Noteus , Squamella , Notom -
mata , and Stephanops, the tail is transversely
marked or articulated. With many species of If y-
datina , Rotifer , Philodina , Actinurus , and Eos-
phora , not only the caudal extremity, but the whole
body, is regularly segmented, and capable, espe-
cially at the posterior extremity, of being intussus-
cepted or drawn out, like a telescope.

3 A solid carapace, like the shell of Daphnia , is
found with Brachionus, Anuraea, Noteus, Salpi-
na and Euchlanis.

1 The muscles are smooth when at rest, but when
contracted, they appear more or less distinctly pli-
cated transversely. The assertion of Ehrenberg
is therefore remarkable, that the longitudinal mus-

cles of Euchlanis triquetra are transversely stri-
ated like those of the higher animals (Die Infus-
iongthierchen, p. 462, Taf. LVII. fig. 8).

2 For the muscles of the Rotatoria in general, see
Ehrenberg, loc. cit. and his description of the Ily-
datina senta, in the Abhandl. d. Berl. Akad. 1830,
p. 47.

3 Many Rotatoria use their caudal pincers as a
fulcrum when creeping along. Philodina moves
along in a leech-like manner, using its mouth and
tail as suckers. Polyarthra has many bundles of
bristles upon the sides of its body, which it uses as
oars. Triart hr a has under the throat and at the
posterior extremity of the body, long stiff bristles,
articulated with the body, and by which these ani-
mals can leap like a flea.

144

TIIE ROTATORIA.

§ 134,

is quite remarkable with those species whose single or double disc is not
crenulate, but entire.® With those whose organs are more numerous, but
smaller, this appearance is not observed.®

With Floscularia , and Stephanoceros, the rotatory organs have quite a
different form. With the first, there are five or six button-like processes
about the mouth, covered with very long bristles ; these bristles produce
usually but very feeble motions, and rarely give rise to vortexes. But Ste-
phanoceros reminds one much of the Bryozoa, for its rotatory apparatus con-
sists of five tentacle-like processes covered with vibratile cilia® The rota-
tory organs differ, moreover, from the ordinary vibratile cilia of epithelium,
in being under the animal’s control, — that is, moved or kept at rest, at
will.®

CHAPTERS III. AND IY.

NERVOUS SYSTEM AND ORGANS OE SENSE.

§ 134.

Notwithstanding the transparency of the Rotatoria, and the distinctness
with which their organs are separated from each other, yet their nervous
system has not yet been made out with certainty, for their bodies are so small
that their peripheric nerves elude the microscope, and their principal nerves
and ganglia cannot be distinguished from the muscular fasciculi, the liga-
ments, and the contractile parenchyma of the body.

It appears certain, however, that in all, there is, as a nervous centre, a
group of cervical ganglia, from which pass off threads in various direc-
tions.®

1 Conochilus , Philodina, and Actinurus.

2 Htjdatina , Notommata , Synchaeta , and Dig-
lena.

3 See Ehrenberg , Die Infusionsthierchen, Taf.
XLV.

4 According to Ehrenberg , there are, at the base
of each cilium of the rotatory organs, many striated
muscles, which, acting antagonistically, produce the
motion (Abhandl. d. Berl. Akad. 1831, p. 34).

But neither Dujardin (Infusoires, loc. cit. p.
579), nor Rymer Jones (Compar. Anat. &c. p.
120), has been able to perceive this apparatus.
The contractile parenchyma on which the virbra-
tile discs are situated, appears to be destined only
for the protrusion and retraction of the rotatory
organs.*

1 Ehrenberg , to whom we are indebted for our
chief information upon the nervous system of these
animals, first took for a cerebral ganglion the gland-

* [ § 133, note 4.] Dobie (Ann, of Nat. Hist. 1848)
speaks of two kinds of cilia with Floscularia ; “ one
of the usual short vibratile kind, covering the inte-
rior of the alimentary tube 5 the other extremely

uliform body found upon most Rotatoria, and in
the neck of Hydatina senta, and Notommata col-
laris (Abhandl. d. Berl. Akad. 1830, p. 52, Taf.
Yin. 1833, p. 189, Taf. IX., and, Die Infusionsthier-
chen, p. 386, &c.). Besides this ganglion, he has
mentioned with Hydatina , Synchaeta , and Dig-
lena , many others scattered through the anterior
part of the body, and connecting with the cerebral
one by nervous filaments. Likewise, with Enter-
oplea, Hydatina , Notommata , and Diglena , he
has regarded as a nervous loop, the two filaments
which pass off from the cerebral ganglion, and go to
the cervical respiratory orifice. Finally, he refers
to the sensitive system, a white sacculus, single or
double, and situated behind the cerebral ganglion,
with Notommata , Diglena , and Theorus (Die
Infusionsthierchen, p. 425). Grant's description of
the nervous system of the Hydatina , as being
composed of many ganglia and a ventral cord.

long and filiform, of uniform thickness, and not
vibratile under ordinary circumstances.” They are
slowly moved, being spread out by the contractile
substance of the lobes of the rotatory organ. — Ed.

4

$§ 135, 136. THE ROTATORIA. 145

§ 135.

Beside the sense of touch, apparently located (j^iefly in the rotatory-
organs and their tentaculiform processes,10 these animals have also an
organ of vision. Usually this consists of a single or double eye-speck
upon the neck ; and sometimes, though rarely, of three or four red specks
upon the forehead.® These specks are usually very small, but nicely defined,
and covered by a kind of cornea. They are situated immediately upon the
cerebral ganglion, or are directly connected with it, by nervous filaments.®

CHAPTER V.

DIGESTIVE APPARATUS.

§ 136.

The digestive apparatus is well developed with the Rotatoria, and has
the following parts :

The mouth opens into a muscular pharynx which has two horny, masti-
catory organs, which move laterally upon each other. Succeeding this
pharynx is a narrow oesophagus of variable length, which leads to a stomachal

(Outlines, &c., p. 88, fig. 82, B.), is founded, un-
doubtedly, upon supposition, and not upon real ob-
servation.*

1 The vibratile disc of Conochiius has upon its
centre, four cylindrical processes, terminating usu-
ally by a bristle, and quite resembling antennae.
The two or four styles projecting from the front of
Synchaeta , are probably of the same nature.

2 The eye-speck is simple with Euchlanis , No-
tommata , Synchacta , Cycloglena , and lirachio-
nus ; double with Conochiius , Megatotrocha,
Diglena , Rotifer , and Philodina ; with Eosphora ,
there^are three, and with Squamella , four •, while
Hydatina , Entcroplea, Ptygura , Tubicolaria ,
and the adult Flosculariae , have none at all.

3 Ehrenberg , who was the first to regard these
red dots as eyes, has given their intimate structure
in none of his writings j this is the more to be

* [ § 134, notel.J Gosse (Ann. Nat. Hist. 1850, p.
21) describes the nervous system of Asplanchnd
priodonta as follows : “ Each of the three eyes rests
on a mass that appears ganglionic j the clubbed
masses at the lateral apertures are probably of the
same character •, and the interior of the body con-
tains a number of very delicate threads, floating
freely in the contained fluid, which have thickened
knobs here and there, especially where they anas-
tomose.”

Ley dig (Zur Anat. und Entwickelungsgeschichte
der Lacinularia socialis, in Siebold and Kollikcr's
Zeitsch. Feb’y, 1852, p. 457) describes a very pecu
liar nervous system with Lacinularia , consisting
of : u 1. A ganglion behind the pharynx, composed

13

regretted since Du jar din has not regarded them
as visual organs (Infusoires, p. 591). He sup-
ports this view by the fact that they disappear with
the adult individual 5 but this objection will appear
valueless when it is remembered that this is also
true of certain parasitic Crustacea. At all events,
the small ocular dots of Conochiius , Rotifer , and
Philodina , are nicely-defined organs surrounded
with a solid capsule, and appear to me wholly dif-
ferent from the ddfused masses of red pigment
which Ehrenberg has erroneously taken for eyes
with the Infusoria. The disproportionate size of
the red dots which Ehrenberg (Die Infusionsthier-
chen, Taf. LI. LIII. LVI.) has figured with Notom -
mata forcipata , Synchacta baltica , Cycloglena ,
and Eosphora , lead one to suppose that they are
only collections of pigmentary granules.

of four bipolar cells with their processes. 2. A gan-
glion at the beginning of the caudal prolongation,
similarly composed of four larger ganglionic cells
and their processes.” But, that these parts belong
to the nervous system, appears by no means posi-
tive ; for, as, this observer candidly observes, and
it is, I think, a capital comment on this whole
class of study •. “ That these cells, with their radiat-
ing processes, are ganglion globules and nerves, is
a conclusion drawn simply from the histological
constitution of the parts, and from the impossibility
of making anything else out of them, unless in-
deed, organs are to be named according to our
mere will and pleasure.” — Ed.

146

THE ROTATORIA.

§ 136.

dilatation. This dilatation is continuous into an intestine which opens exter-
nally by an anus.

The mouth is always between the rotatory organs, so that it receives
what is drawn in by t&eir vortical action, — the animal swallowing or re-
jecting the particles at will. cl)

The pharyngeal masticatory apparatus is round, and composed of two
jaws having one or several teeth, which are brought together laterally by
the action of special muscles. <2)

Usually these jaws are formed of two knee-shaped divisions ( Processus
anterior and posterior). The posterior division gives insertion to the masti-
catory muscles, but the anterior terminates with a tooth,® or as a multi-
dentate apophysis.® With some which have this last arrangement,® the
two jaws are formed of three horny arches, and noted for their stirrup-like
form. Two of these arches [Arcus superior and inferior ), form the arched
portion of the stirrup, pointing inwards, while its base is formed by the
third arch [Arcus externus ), pointing outwards. The masticatory muscles
are inserted upon the inferior arch, and move against each other — the
transversely-arranged teeth passing over the other two.

With the multidentate Monotrocha, and Zygotrocha, the pharynx rests
always in the same locality ; but with the unidentate Polytrocha, it can
move up and down, and even be protruded through the mouth. In this
last case, the teeth serve as pincers for the seizure of food. The intestine
usually traverses the cavity of the body in a straight line, rarely loop-
ing,® and is lined throughout with ciliated epithelium.

Prom the stomachal dilatation to a point near the anus, its walls are
very thick. The walls of the stomach and intestine are formed of large
cells with a colorless nucleus, and which, as they contain a brownish or
greenish granular substance, are of an hepatic nature.

With mogt species, two caeca, rarely more, with thick walls and lined
with ciliated epithelium, open on the right and left of the beginning of the
stomach. Their walls are also composed of large cells, which, as they
differ widely from the hepatic ones by their colorless contents, may perhaps
serve the function of salivary glands or pancreas.®

The term Rectum has been given to a short and terminal portion of the
intestine, which has thin walls, capable of being widely distended by faeces.
Its orifice is excretory not only of the faeces, but also of the contents of
the genital organs and of the aquiferous system — and may therefore be
regarded as a cloacal as well as an anal opening. It is nearly always at
the base of the caudal extremity.

1 The tentaculiform, rotatory organs of Stephano-
ceros , are also used for the seizure of food 5 see
Ehrenberg , Abhandl. d. Berl. Akad. 1832, Taf.

XI. fig. 1, e., also, Die Jnfusionsthierchen, Taf.

XLV. fig. II. 5.

2 For the structure of the teeth, see Ehrenberg ,

Abhand. d. Berl. Akad. 1831, p. 46, Taf. III. IV.

3 Pleurotrocha , Furcularia, and many species
of Notommata , and Diglena.

4 Hydatina , Euchlanis , Salpina , Anuraea ,

Brachionus , and many species of Notommata ,
and Diglena.

5 Philodina , Lacinularia , Melicerta , and
Conochilus.

6 With Euchlanis , and Brachionus , the stom-
ach is separated from the intestine by a constric-
tion, and with Philodina , the intestine is of equal

size throughout, except the rectum which is dilated.
But it is coiled, especially with those which are
enclosed in a carapace, as with Tubicolaria , and
Melicerta , since here the anus is far in front.

7 These two pancreatic caeca are nearly always
present, being wanting only with some species of
Ichthydium. With Notommata clavulata , and
Diglena lacvstris , there are, besides these caeca
which are long, attached to the stomach many
smaller sacs, which are colorless and perhaps of
the same nature.

With Megalotrocha albo-Jlavicans , there are
also two like caecal appendages entering the base
of the stomach, and which are independent of the
short pancreatic ones of the same locality $ see
Ehrenberg , Abhandl. d. Berl. Akad. 1831, Taf.
III. and, Die Infusionsthierchen, Taf. L. LIV.

$§ 137, 138.

THE ROTATORIA.

147

CHAPTERS VI. AND VII.

CIRCULATORY AND RESPIRATORY SYSTEMS.

§137.

As no sanguineous system has yet been found with the Rotatoria, it must
be admitted that all the organs are bathed directly by the nutritive liquid
which transudes through the intestine. a)

§ 138.

The vessels observed with the Rotatoria belong probably to the aquiferous
system, which, from its structure and limited distribution, must be regarded
as of a respiratory nature. In most species, a straight and riband-like organ
is seen upon each side of the body, which contains a stiff, tortuous, Yasculi-
form canal. At the anterior extremity of these two lateral bands, their
canals connect with many short lateral vessels which open into the cavity
of the body, — their orifices being furnished each with a very active, vihra-
tile lobule. (1)

These lateral orifices have the appearance of pyriform, or oval corpus-
cles, in the interior of which, the vibratile lobule, produces the aspect, when
its motions are diminished by pressure between plates of glass, of a small,
flickering flame.

The number of these organs varies with the species, and also, it would
appear, even with different individuals of the same species. Usually there

1 The sanguineous vessels which Ehrenberg has
frequently described and figured, have not ap-
peared as such to Dujardin (Infusoires, p. 689),
Rymer Jones (Comp. Anat. p. 125), Doy&re
(Ann. d. Sc. Nat. XVII. 1842, p. 201), and my-
self.

The so-called annular vessels encircling the body
of many species at regular and wide distances, and
which, as he himself avows (Die Infusionsthier-
chen, p. 415), are not connected by longitudinal
vessels, are undoubtedly only the transverse sulca-

*(§ 137, note 1.] Dalrymple (Phil. Trans.
1849, p. 334) has described with Asplanchna
Brightwellii what he regards as a peculiar cir-
culatory system. It “ consists of 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 sym-
metrical when viewed in front. These filaments,
above and below, are interlaced loop-like 5 while
another fine filament passes in a straight line, like
the chord of an arc, uniting the two looped extrem-
ities. To this delicate filament are attached tags.

tions, or muscles. From their extreme tenuity, it
is difficult to determine the nature of the other fili-
form organs in the body of the Rotatoria, and which
Ehrenberg has also referred to the sanguineous
system. But, equally well might they be taken for
muscular fasciculi, ligaments or nerves.*

l Ehrenberg was the first to point out these
vibratile organs, and designated them as the inter-
nal gill-like respiratory organs (Abhandl. d. Berk
Akad. 1833, p. 183).

or appendices, whose free extremities are directed
towards the interior of the animal, and are affected
by a tremulous, apparently spiral motion, like the
threads of a screw. This i3 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.” He
thinks these organs fulfil their function by the cil-
iated tags producing currents in the fluid which
fills the body of the animal.

These observations are curious and deserve fur-
ther attention. — Ed.

TIIE ROTATORIA.

148

§ 139.

are two or three on each side, and sometimes there are from five to eight
pairs,® but rarely more.®

The lateral bands approach each other at the posterior extremity, and
their canals join in a common, highly-contractile vesicle with thin walls,
which empties externally its aqueous contents through the cloacal open-
ing.®

An orifice, situated usually upon the neck, and sometimes pedunculated,
serves probably to introduce the water into the cavity of the body. This
water enters the aquiferous system through the lateral vessels which float
free in this cavity, and at last is expelled through the contractile vesicle.
In this way, a constant renewal of water can occur, and the opening upon
the neck may therefore be properly termed a respiratory orifice or tube.®

There can be but little doubt that the rotatory organs also, have a respir-
atory function, for their surface is covered with thin epithelium, and their
cilia produce a constant change of the water.

CHAPTER VIII.

ORGANS OF SECRETION.

§ 139.

Some of the Rotatoria secrete a gelatinous substance, which, hardening,
forms the cells and tubes into which they can partly or wholly withdraw
themselves. The organ of this secretion is yet unknown ; but the secretion
appears to be derived from the posterior extremity, and especially from the
cloacal opening. a)

2 Notommata copeus , and syrinx.

3 With Notommata clavulata , and myrmeleo ,
the number of these organs is remarkable ; each
lateral band has thirty-six to forty-eight ; see
Ehrenberg , Die Infusionsthierchen, Taf. XLIX. L.

4 Ehrenberg was the first to direct the atten-
tion of naturalists to these two lateral bands and
their contractile vesicles 5 but he regarded them
as two testicles with their vesiculae seminales
(Abhandl. d. Berl. Akad. 1830, p. 51). The incor-
rectness of this opinion, and which he has main-
tained in his grand work, cannot be doubted, if it
is considered that these two bands with their
appendages are already developed and in activity
with the young animals, and this even before they
have escaped the cavity of the parental body.

In all Ehrenberg's published figures, one 110-
tioes nothing of the flexuous canals of these or-
gans, and which, therefore, he does not appear to
have observed.

5 The respiratory orifice is cervical with j Enter 0-
plea, Hydatina , Diglena , and many species
of Notommata j but, with Rotifer , Philodina ,

Brachionus , and some species of Salpina , Euch-
lanis , and Notommata , it is replaced by a tube.

With Actinurus1 exceptionally, a simple res-
piratory tube is placed under the throat j and with
Tubicolaria , and Melicerta , there are two in the
same region.

1 With Conochilus , and Lacinularia , where
several individuals are attached by their tails
around a common centre, the nucleus of one of
these colonies is formed by a loose, gelatinous sub-
stance, in the cells of which these animals can par-
tially withdraw themselves. With Oecistes , Tu-
bicolaria, Stephanoceros , Floscularia , and Lim-
nias , each individual occupies an isolated and
more or Jess hard gelatinous tube ( Ehrenberg , Die
Infusionsthierchen). The tubes of Melicerta , of
which Schaffer has given an excellent figure (Die
Blumen-polypen der siissen Wasser 1755, Taf. I.
II.), are very remarkable, and according to Ehren-
berg, are composed of brown polygonal cells which
are excreted through the cloacal opening and
glued together (Die Infusionsthierchen, p. 406).

$ 140.

THE ROTATORIA.

149

CHAPTER IX.

ORGANS OF GENERATION.

§ 140.

Although it is certain that the Rotatoria propagate only by genital
organs, yet the female organs only are yet well known. These consist of a
single or double ovarian tube of variable length, situated upon the sides of
the intestinal canal at the posterior part of the cavity of the body, and
opening into the cloacal cavity through a short oviduct. These ovaries
never develop but a few eggs at a time. The mature eggs are always
oval and surrounded by a simple, solid, colorless envelope. They contain
a finely granular and usually colorless vitellus, in which there is a distinct
germinative vesicle. Many species are ovigerous, but a few only are vivi-
parous. a)

It would be naturally supposed that these animals, which have such dis-
tinct female organs, would have also those of the other sex. But as yet the
most minute researches have failed to detect them. It is therefore doubt-
ful whether these animals are hermaphrodites or of separate sexes.t <2>

1 For the various forms of the ovaries see the
classical works of Ehrenberg. With Philodina
roseola , Brachionus rubens , and Mastigocerca
carinata , the vitellus of the eggs as well as the
parenchyma of the body is of a reddish color.
With those species which live in the tubes, the
eggs are usually deposited in the cavity of these
last. But with Triartkra , Polyarthra , and
Brachionus , they remain glued to the cloacal
opening.

With Philodina , the young are often hatched
in the cavity of the parental body, and are, accord-

* [ § 140, note 1.] The view here expressed that
the young of the viviparous Ph ilodinae may find
their escape from the body of the parent through
an opening near the anus — the oviducts being
perhaps wanting — is probably correct, since, in the
viviparous Aphides, where the processes of repro-
duction occur likewise by a kind of gemmiparity,
there are, according to my observations, no ovi-
ducts proper, but the young, having fallen into the
abdominal cavity, thence escape through a Porus
genitalis situated near the anus. — Ed.

t { End of § 140.] The discovery of distinct
males with the Rotatoria is due to Brightwell
(Ann. Nat. Hist. Sept. 1848) who has positively
determined it with Asplanchna. Here it is about
half the size of the female, being also of a different
form ; it is exceedingly transparent and easily eludes
observation. The testis appeared as a round ves-
sel situated at the bottom of the body on one side,
and filled with spermatic particles. This author

13*

ing to Ehrenberg (Die Infusionsthierchen p. 483),
always surrounded with an extensible membrane
of the ovary (uterus). But it has always appeared
to me that the mature eggs of the viviparous Phi-
lodinae, are detached from the ovaries and fall into
the cavity of the body, where afterwards the
hatched young move about. Perhaps oviducts are
here wanting and the young escape from their
parent through an orifice near the cloacal open-
ing.*

^ Admitting that there are here male genital
organs, the respiratory tube upon the neck of

thinks also that he observed a well-defined intro-
mittent organ connected with the testis, and a
passage for its extension from the body of the
animal.

In verification of this observation it may be men-
tioned that Brightwell observed the actual coitus
between the sexes, and Gosse (loc. cit. p. 22) has
witnessed the development of the males from the
ovum.

Huxley , on the other hand (Quat. Jour. Mic.
Sc. No. I. Oct. 1852, p. 1), has found with Lacin-
ularia no trace of a male individual, but in some
specimens he observed singular bodies which
answered precisely to Ko/li/cer's description of the
spermatic particles of Megalotrocha. He says,
“ They had a pyriform head about 1-1000 in. in
diameter by which they were attached to the parietes
of the body, and an appendage four times as long
which underwent the most extraordinary contor-
tions, resembling however a vibrating membrane

160

THE ROTATORIA.

§141.

§141.

Their embryonic development occurs, as in most invertebrate animals,
through a complete segmentation of the vitellus ; aud the embryonic cells
then appear in the segmented portions.

The newly -hatched embryo has already rotatory and masticatory organs,
eye-specks, &c., and the general form of the adult animal.t ®

many species was formerly taken for a penis. But
Li incorrectness of this view has since been seen,
1 -r no one lias here observed the copulatory act.
According to Ehrenberg, who regards these ani-
mals as hermaphrodites, certain parts of the aquif-
erous system represent the male organs. He
regards the two lateral bands as testicles, and
their inferior extremities as vasa deferentia, while
the contractile vesicle is the vesicula seminalis.
But these organs contain only an homogeneous
aqueous fluid, m which there is at no time anything
1:. • spermatic particles j moreover they are fully
developed in the young individuals which then
have no trace of female organs.

It would be wholly anomalous that these ani-
mals should constantly secrete sperm during their
whole life. One would therefore wholly assent to
the doubts of Dujardin (Infnsoires, p. 587), upon
this view of Ehrenberg , and some contradictions
into which this last has fallen upon this subject,
have been noticed by Doylre (Ann. d. Sc. Nat.
XVII. 1842, p. 199). Kblliker has also thought
this view unfounded, and has sought to remove
the doubts by a search after the spermatic parti-
cles. He regards as such, with Megalotrocha
albojlavicans , the peculiar trembling bodies which
he has seen in the cavity of the body, since they
are composed of a pryiform body, to which is
attached a movable tail. These bodies he affirms
are developed in round cells, often nucleated, and
he has often counted ten to twenty in the same
individual. As he also asserts to have seen eggs
at this time in the same individual, this would cer-
tainly be a proof of the hermaphroditism of these

more than the tail of a spermatozoon.” He very
justly concludes that they cannot at present be
definitely regarded as spermatic particles. — Ei>.

* [ § 140, note 2.] The subject of the form and
character of the spermatic particles of the Rotatoria
is quite interesting, as it may perhaps throw some
light on the position of these animals in the animal
kingdom. As yet, however, we have very few
observations, and even these are not fully defi-
nite.

Schmidt (Vergleich. Anat. &c. p. 268, note)
speaks of the spermatic particles of Euchlanis
macrura , as being cercaria-form.

Leydig ( Siebold and Kolliker's Zeitsch. III.
lift. 4, p. 471) has given those of Lacinularia as
composed of a nuclear body from which radiate
many tails, like these particles with the Decapods.
See Taf. XVII. fig. 2. — Ed.

t [End of § 141.] We are indebted to Ley dig
(Zur Anat. u. Entwickelungsgesch. d. Lacinularia
socialis, in Siebold and Kblliker' s Zeitsch. III. p.

animals (Fr or tip's neue Not. No. 28, 1843, p.
17). But this whole observation is somewhat sus-
picious, for Kblliker has very probably confounded
the vibratile lobules of the aquiferous system with
the spermatic particles, and of which there are four
witli Megalotrocha in the anterior extremity.

The observation of R. Wagner (Isis, 1832, p. 386,
Taf. IV. fig. 1, 7) is particularly worthy of atten-
tion, for followed out, it might lead to the discovery
here of male genital organs. He has described
peculiar eggs, found frequently by him with Hy-
dat.ina senta , and whose whole surface is covered
with very fine, thickly-set hairs. He has regarded
these as in their first stages of development,
although Ehrenberg (Abhandl. d. Berl. Akad.
1835, p. 154, and, Die Infusionsthierchen p. 415)y
has taken this villous envelope for an alga of the
genus Hygrocrocis. But these villous envelopes
have always reminded me of the masses of sperm-
atic particles in the testicles of leeches and which
have been figured by Henle as whitish felt-like
globules {Muller's Arch. 1835, p. 584, Taf. XIV.
fig. 6. a).

[Additional Note.) Kblliker (Neue Schweiz.
Denkschr. VIII. Taf. II. fig. 31, a.) having since
figured the spermatic particles of Megalotrocha
albo-Jiavicans, my former view that he had con-
founded these with vibratile organs, is incorrect.’*'

1 Kblliker was the first to observe the complete
segmentation of the eggs, with Megalotrocha
(Froriep's neue Not. loc. cit.). It wholly escaped
the observation of Ehrenberg amid his numerous
researches upon the eggs of these animals •, see
Abhandl. d. Berl. Akad. 1835, p. 152.]:

452) and to Huxley (loc. cit. p. 11-15), for extend-
ing our knowledge in this direction. They have
carefully observed the development of Lacinu-
laria, and the phases correspond exactly with
those of Megalotrocha as described by Kblliker..
But beside this ordinary mode of reproduction,
they have observed another which is a sexual and
analogous if not identical with what has been
observed with some of the lower Crustacea (see
infra § 292), — propagation by the so-called hiber-
nating eggs. Their observations throw light on the
whole of this interesting subject, and have fully
confirmed me in my previous conjectures that these
u Ova ” are only gemmae having their exact repre-
sentative in the bud-like eggs of the viviparous
Aphides. — Ed.

% [§ 141, note 1.} Kblliker's observation above-
mentioned on Megalotrocha , has since been con-
firmed by Leydig (Isis, 1848, p. 170) who has
observed it likewise with Notommata and Each r-
lanis. — Ed.

•s

BOOK EIGHTH.

ANNELIDES.

* CLASSIFICATION.

§142.

I

The Annelides are distinguished from all other worms by their ventral',
ganglionic cord, and by their annulated body, at the two extremities of
which there is a mouth and anus. They resemble the Arthropoda, but at
the same time differ from them in having a completely closed vascular sys-
tem, and in wanting articulated, locomotive organs. The epithelium of
their body is not ciliated except where it covers the external branchiae.

The Nemertini, which have hitherto been classed among the Turbellaria,
belong more properly to the Annelides, since their body is more or less dis-
tinctly articulated, and its parenchyma closely reseipbles that of the Hiru-
dinei. Moreover, the power which many of them have to divide sponta-
neously into many segments, is another affinity with various Annelides. It
will therefore appear proper to unite the Nemertini with the other Anne-
lides in the following manner : (1)

ORDER I. APODES.

Body without bristles.

%

SUB-ORDER I. NEMERTINI.

Posterior extremity of body without a sucker; cephalic extremity often
provided with lateral respiratory fossae.

1 Since Kolliker (Verhandl. d. Schweiz, naturf.
Gesellsch. zu Chur. 1844, p. 89) and Quatre-
fages (Ann. d. Sc. Nat. VI. 1846, p. 173) have
published their researches on the anatomy of
the Nemertini, I have, also, during my last

visit at Trieste in 1847, been convinced that
these animals should be classed among the Tur-
bellaria, and that they especially cfeserve this name
since their entire body is covered with very dis-
tinct vibratile cilia. — Additional note.

152 TIIE ANNELIDES. § 142.

Genera : Tetrastemma, Polysiemma, Micrura, Notospermus, Meckelia,

Folia , Nemertes, Borlasia.

SUB-ORDER II. HIRUDINEI.

Posterior extremity of body provided with a sucker.

Genera : Branchiob della, P'iscicola , Clepsine, Nephelis, Haemopis, Aulaco-
stomum, Sanguisuga, Pontobdella.

ORDER II. CHAETOPODES.

Body provided with bristles.

SUB-ORDER III. LUMBRICINI ( ABRANCHIATI .)

Body without feet.

Genera : Chaetogaster, Enchytraeus, Na'is, Lumbriculus, Euazes, Saenu-
ris, Lumbricus, Sternaspis.

SUB-ORDER IV. CAPITIBRA NCHIA TI.

Body provided with feet; branchiae situated upon the cephalic ex-
tremity.

Genera : Siphonostomum, Chloraema, Amphicora, Serpula, Sabella, Am~
phitrite, Terebella.

SUB-ORDER V. D ORSIBRANCHIA TI.

Body provided with feet ; branchiae situated upon its segments.

Genera : Arenicola, Ammotrypane, Chaetopterus , Aricia, Aricinella, Cir-
ratulus, Peripatus, Glycera, Goniada, Nephtys, Alciopa, Syllis, Phyllo-
doce, Hesione, Lycastis, Nereis, Oenone, Aglaura, Lumbrinere'is, Eunice ,
Amphinome, Sigalion, Polynoe, Aphrodite.

BIBLIOGRAPHY.

Pallas. Miscellanea zoologica. Hague, 1766, p. 72.

O. F. Muller. Yon den Wiirmen des siissen und salzigen Wassers.
Copenhagen, 1771.

Savigny. Description de PEgypte. Histoire Naturelle. Tom. XXI.

1826. Annelides. Also, Isis, 1882, p. 937.

Mocpuin-Tandon. Monographic de la famille des Hirudinees. Paris,

1827.

Morren. De lumbrici terrestris historia naturali, nec non Anatomia.
Bruxelles, 1829.

§ 142. THE ANNELIDES. 153

Andouin et Milne Edwards. Classification des Annelides, et descrip-
tion des especes qui habitent les cotes de la Prance, in the Annales des
Sciences. Tom. XXVII.— XXX. 1882—33, but published separately under
the title, Recherches pour servir a Vhistoire naturelle du littoral de la
Fratice. Tom. II. Paris, 1834.

Ehrenberg. Symbolae physicae. Phytozoa turbellaria.

Milne Edwards. Cyclopaedia of Anatomy and Physiology, vol. 1,
1836. Art. Annelida.

Grube. Zur Anatomie und Physiologie der Kiememviirmer. Kfinigs-
berg, 1838; also, Aktinien, Echinodermen und Wiirmer des Adriutischen
und Mittelmeers. Konigsberg, 1840.

Orsted. Gronlands Annulata dorsibranchiata. Ivjobenhaven, 1843.
Annulatorum Danicorum conspectus. Fasc. I. Maricolae. Ilafniae, 1843.
Entwurf einer systematischen Eintheilung und speciellen Beschreibung der
Plattwfirmer. Copenhagen, 1844.

Hoffmeister. De vermibus quibusdam ad genus lumbricorum pertinen-
tibus. Berolini, 1842.

Rathke. Zur Fauna der Krim. St. Petersbourg, 1836, p. 117. De
Bopyro et Nerei'de. lligae, 1837. Beitrage zur vergleichcnden Anatomie
und Physiologie; in the Neuesten Schriften der Naturforschenden Gesell-
schaft in Danzig, III. Hft. 4, 1842, p. 56. Beitrage zur Fauna Norwe-
gens; in the Nov. Act. Acad. Nat. Cur. XX. pt. 1. 1843, p. 149.

ADDITIONAL BIBLIOGRAPHY.

Besides the references in my notes, see the following writings :

Moquin-Tandon. Monographic de la Familie des Hirudinees. Nouv.
Ed. revue et augmentee, accompagnee d’un Atlas de 14 planches gravees
et coloriees. Paris, 1846.

Schmidt. Neue Beitrage zur Naturgeschichte der Wiirmer. Jena. 1848.
(zweiter Abschnitt, Ringelwiirmer).

Quatrefages. Etudes sur les types inferieurs de l’embranchement des
Anneles, containing: Memoire sur la Familie des Hermelliens, Ann. d. Sc.
Nat. 1848, X. p. 1.; Sur la Circulation des Annelides, Ibid. XIV. 1850,
p. 281 ; Sur la Respiration des Annelides, Ibid. XIV. 1850, p. 290; Me-
moire sur le Systeme Nerveux des Annelides, Ibid. XIV. 1850, p. 329;
Memoire sur le Systeme Nerveux, et les affinities et les analogies des Lom-
bries et des Sangsues, Ibid. XVIII. 1852, p. 167 ; Memoire sur le Bran-
chellion de D’Orbigny, Ibid. XVIII. 1852, p. 279. Note sur le Systeme*
Nerveux et sur quelques autres points de l’Anatomie des Albiones, Ibid.
XVIII. 1852, p. 328.

Memoire sur l’Embryogenie des Annelides. Ibid. X. 1848,

p. 153.

Leydig. Zur Anatomie von Piscicola geometriea mit theilweiser Ver-
gleichung anderer einheimischer Hirudineen, in Siebold and KUliker's
Zeitsch. I. 1849, p. 103.

Anatomisches fiber Branchellion und Pontobdella. Ibid.

III. 1851, p. 315.

Leidy. Descriptions of some American Annelida abranchiata, in the
Jour. Acad. Nat. Sc. Philad. 1850, II. p. 43 [contains many anatomical
details]. — Ed.

154

THE ANNELIDES.

§§ 143, 144.

CHAPTER I.

CUTANEOUS SYSTEM.

§143.

The skin of the Annelides consists of a very thin, non-ciliated epidermis, (1)
and a more or less compact dermis composed of solid, but delicate fibres
obliquely intertwisted.

The iridescence and often splendid colors of many of the Chaetopodes,
are not due to a pigment, but to an optical effect produced by the reticu-
lated union of the dermic fibres.

But the Apodes, on the other hand, owe their many colors to a pigment
net-work and cells. Usually the epidermis is separated with difficulty from
the dermis, but with many Capitibranchiati, and Dorsibranchiati, the oppo-
site is true. With the Apodes, the skin is closely united with the subja-
cent muscular layer.

With many Dorsibranchiati, the skin has filiform or lamellar appendages
sometimes so much developed that they overlap each other like scales. <a
With some Chaetopodes, there are, beside the bundles of locomotive bris-
tles and hairs, numerous appendages of this kind covering most of the
body.®

CHAPTER II.

MUSCULAR SYSTEM AND LOCOMOTIVE ORGANS.

§144.

The muscles of the Annelides, although highly developed, are never stri-
ated.

The whole body is enveloped by a subcutaneous muscular layer divisi-
ble into three sheets : an external, of circular fibres; an internal, of longi-
tudinal fibres; these are the most developed. Then a middle one com-
posed of obliquely intertwisted fibres ; this is less distinct, and sometimes
entirely wanting.®

I The external respiratory organs alone are
covered with ciliated epithelium. Orsted (Beschreib.
d. Plattwiirmer, loc. cit. p. 77) however, affirms
that the body of the Nemertini is provided with
vibratile cilia. But this is to me improbable at
least with the large species of Borlasia , Nemertes ,
and Folia .

At all events this statement of his requires new
proof. See additional note under § 142.

- Scaly appendages of this kind cover the back
of Aphrodite , Polynoe , and Sigalion. With
Polynoe squamata , they are very easily de-
tached.

3 The back of Aphrodite hystrix has numerous
bristles and hairs ; with Aphrodite aculeata , these
hairs are so thickly set that they conceal the back
by a kind of felt.

1 The middle muscular sheet is found with the
Hirudinei and Lumbricini ; see Brandt and Rat -
zeburg , Med. Zool. II. p. 244, Taf. XXIX. fig. 1,
2, and Morren , loc. cit. p. 83.

But with the Nemertini it is wanting *, see
Rathkd, Neueste Schrift. d. naturf. Gesellschaft, in
Danzig, loc. cit. p. 95.

§ 145.

THE ANNELID ES.

155

With the Apodes, this muscular envelope so closely embraces the viscera,
that the cavity of the body is made very small. But with the Chaetopo-
des, this cavity is larger.

With many of the Branchiati, the muscular fibres form distinct fasciculi
— so that instead of a common muscular envelope there are longitudinal
and annular muscles distinct from each other.®

With many Chaetopodes, the internal surface of this envelope sends off
annular muscular septa into the cavity of the body, at the junction of the
segments, — thus dividing this last into as many chambers as there are
segments ; sometimes these septa bind the intestinal canal so closely, as to
regularly constrict it.(3)

§ 145.

Besides the common subcutaneous muscles, which produce the vermicu-
lar motions of the body, there are other groups : 1st. For the auxiliary
locomotive organs, and 2nd, for many other organs.

1. The Hirudinei are distinguished, as is well known, by a sucker situ-
ated at their posterior extremity, which contains both circular and radiating
muscular fibres. This sucker serves both to move and to attach the body.

All the Chaetopodes have short, horny stings ( aciculi ), and long bristles
[setae), united in fasciculi of various forms, which they use as fulcra
when they creep, or as oars when they swim.

With the Branchiati, these organs are most fully developed, and are nearly
always situated laterally upon a double row of fleshy knobs ; and those of
the two inferior rows may be regarded as rudimentary feet.

The Lumbricini have short and usually S-shaped stings which are ar-
ranged in many rows upon the belly, and may be wholly withdrawn into
the abdominal cavity.

Beside these last, Na'is has also a row of bristles each side of the
body.®

2 These separate muscles are found in Aphro-
dite, Polynoe , and Nereis , with which the longi-
tudinifl ones especially, are seen separated into
dorsal, ventral and lateral layers. See for the
subcutaneous muscles of the Branchiati in gen-
eral, Rathfcd , De Bopyro et Nere'ide, p. 29, Tab.
II., and in the Danzig. Schrift. loc. cit. p. 62, Taf.
IV. fig. 6 •, also Grube , Zur Anat. und Physiol, d.
Kiemenwurmer, p. 4. et seq.

•'3 When these septa are largely developed, and
embrace closely the digestive canal, as in Lum-
bricus , Sabella , Serpula , and Eunice, there are
always foramina in these diaphragms or septa,
through which the contents of the cavity of the
body can pass from one chamber into another.*

1 The stings and bristles of the Abranchiati,
upon whose various forms see Orsted (Conspectus
generum specierumque Na'idum, in Kr dyer's
Naturhistor. Tidskrift. IV. 1842, p. 128, PI. III.),
are easily lost from use, but are as easily repro-
duced.

* [ § 144, note 3.] The development and inti-
mate structure of the muscles of the Annelides has
been carefully studied by Leydig ( Siebold and
Kolliker's Zeitsch. I. 1849, p. 103) upon Pisci -
co/a, Clepsine , Nephelis , and other Hirudinei.
The muscular fibre is here developed as in the
higher animals out of large nucleated cells arranged
in rows, and the adult fibre often shows the relics

The number of these organs may therefore vary
very much upon the different segments of the same
individual. It is remarkable that with the Lum
bricini the stings are often detached interiorly, and
falling into the cavity of the body form there tough
masses which are glued together by a viscous sub-
stance lodged in the posterior chambers of the
body ; see Hoffmeister , De vermibus quibusdam
loc. cit. Tab. II. fig. 3, and in JViegmann's Arch.
1843, I. p. 196. These agglutinated masses in
which are lodged usually various kinds of vibrioid
parasites, have been taken by Montigre (Observ.
sur les Lombries, in the M6m. du Museum I. p.
246, fig. 5, 6, g) for the eggs and fcetuses of the
Lumbricini. Moreen (loc. cit. p. 195, Tab. XXV.-
XXLX.) has gone even further, by taking these
stings for the chrysalids, and their enclosed vibrios
for the embryos of these animals.

of these elementary parts. The fibre is not trans-
versely striated, and is composed of a structureless
envelope or sheath which is filled with a fine
granular substance ; see loc. cit. Taf. VIII. fig.
13- 23.

See also Holst , De struct. Muscul. in genere et
annulat. musculis in specie, Diss. Dorpate, 1846,
— Ed.

156

THE ANNELIDES.

§ 146.

With the Branchiati, these organs are often of a cultrate, lanceolate,
or sagittate form. Often too, they are denticulated, or barbed upon one
or both of their sides, and sometimes they appear articulated.® These
stings and bristles are moved by a special, muscular apparatus, consisting
of many short muscles which arise from the internal surface of the cavity
of the body and pass obliquely front and behind to the bases of these
organs. These bases project into the cavity of the body, and as their fas-
ciculi are surrounded by a common membranous sheath, when all the mus-
cles contract at once, these organs are thrust out : but they move in va-
rious ways, when the muscles contract separately. The other transverse
muscles which pass either from the median line of the belly, or from the
anterior and posterior parts of the body, and are inserted at the base of
these organs, retract them anew into the cavity of the body.®

2. With many Branchiati, there is a group of longitudinal muscles at
the cephalic extremity, which, arising from the internal wall of the ante-
rior segments, act as elevators and depressors of the oesophagus,2 * (4) as well
as retractors and protractors of the fasciculi of the cephalic bristles and
tentacles.®

CHAPTER III.

NERVOUS SYSTEM.

§ 146.

The nervous system is highly developed in all the Annelides excepting
the Nemertini.

The central is distinctly separated from the peripheric portion. The
first is usually composed of a row of ganglia, joined together by nervous
cords upon the median line of the body.

The most anterior ganglion, and which in some respects may be consid-
ered analogous to the brain of the higher animals, rests upon the oesoph-
agus, although the rest of the ganglionic chain which is situated on the
median line under the digestive canal, may be regarded as a ventral cord.
This cerebral ganglion differs from the others in its larger volume, and
appears to be the product of a fusion of two or more symmetrically-arranged
unequal-sized ganglia. These ventral ganglia are of uniform size, although
not always of the same number with the segments of the body.
Strictly, each of them is composed of two ganglia blended together either
very perfectly, or very incompletely. The cerebral ganglion is joined to
the first of the ventral chain by two cords which surround the oesophagus

2 For the nearly inexhaustible variety of form
of these horny locomotive organs, which, when

cultrate, or lanceolate, are used as weapons of de-
fence, 6ee Audouin and Milne Edwards , Classifi-
cation des Annelides, loc. cit. XXVII. p. 370, and

Orsted , Grdnlands Annulata und Annulatorum
Danicorum Conspectus, fasc. I. PI. I.

3 See Rathkt, De Bopyro et Nereide, p. 31, Tab.
II. fig. 7, 12 *, Grube , Zur Anat. d. Kiemenwiirmer
p. 5 •, and Gruithuisen , Anat. d. geziingelten
Naide, in the Nov. Act. Acad. XI. p. 240, Tab.
XXXV.

4 Aphrodite , Nereis , and Arenicola.

I Amphitrite , and Siphonostomuim

§§ 147, 148.

THE ANNELIDES.

157

laterally, thus forming a ring (the oesophageal ring) through which the
oesophagus passes.

§147.

The histological elements of the nervous system of these animals, are
arranged in the following manner: (1)

o o

The central mass of the nervous system is enveloped by a fibrous tissue
( Neurilemma ), of longitudinal and transverse fibres which are often covered
with special pigment cells.

The nervous cords and filaments are composed of extremely fine, primi-
tive fibres, between which in the ganglia are situated various-sized cell-like
ganglionic globules.® Some of these primitive fibres pass from the cere-
bral ganglion through all the ventral ganglia, while others pass off
from the central ganglia to the peripheric nerves. Many of the ganglionic
globules of the brain and abdominal cord are remarkable for their longer
or shorter prolongations which may be traced even into the roots of the
nerves.®

§ 148.

The nerves are given off usually from the ganglia, and rarely from the
interganglionic cord. The cerebral ganglion sends off nerves to the organs
of sense in the head, and to the labial, proboscideal, and masticatory organs
about the mouth. Its development therefore corresponds exactly to the
more or less complicated condition of the cephalic extremity.

The ventral ganglia send off from each side usually two or three sym-
metrically-arranged main nerves to the muscles and skin.

It is with the Annelides that there have been found the first traces of a
vegetative or splanchnic nerve ( Nervus splanchnicus). This consists of deli-
cate filaments which are distributed upon the intestinal canal, with here and
there enlargements, and which anastomose, some directly with the oesophageal

1 Our knowledge of the intimate structure of the
nervous system of the Annelides is as yet based
upon researches of that of the Hirudinei only *, see
Helmholtz , De fabrica systematis nervosi everte-
bratorum dissertatio. Berol. 1842, p. 12 •, Hanno-
ver, Recherches microscopiques sur le systthne
nerveux, Copenhague, 1844, p. 72-, Will , Vorlau-
fige Mittheilung fiber die Struktur der Ganglien
und den Ursprung der Nerven bei wirbellosen
Thieren, in Muller's Arch. 1844, p. 82 •, Ehren -
berg, Beobachtung einer auffallenden, bisher uner-
kannten Struktur des Seelenorgans bei Menschen
und Thieren, in the Abhandl. d. Berl. Akad. 1834,
p. 720, Tab. VI. fig. 7 *, and Valentin, Ueber den
Verlauf und die letzten Enden der Nerven, in the
Nov. Act. Acad. XVIII. 1836, p. 202, Tab.
VIII.

2 Valentin declares that he has seen in the brain

* [ § 147, note 3.] This alleged relation of the
elements of the nervous tissue is a point of no little
histological importance and I shall give it a special
consideration in noticing the minute structure of
this tissue with the higher animals. I have made
no observations on the animals in question, but

14

and ventral ganglia of the leech so regular and
symmetrical an arrangement of the ganglionic
globules, that those of the two lateral halves cor-
responded exactly as to number, volume and posi-
tion 5 see Valentin , loc. cit. p. 208, Tab. VIII. fig.
62, &c. This symmetry must appear highly aston-
ishing.

3 These prolongations give the ganglionic glob-
ules a clavate aspect, as already seen and figured
by Ehrenberg (loc. cit. Tab. VI. fig. 7, and fig.
7. ll., 7.12 ).

Further researches must decide if these prolon-
gations are really continuous with the primitive
nervous fibres, as Helmholtz (loc. cit. p. 15), and
Hannover (loc. cit. p. 73, Tab. VI. fig. 78), affirm
to be the case ; for, Valentin in his apparently so
careful researches, has never Seen any trace of a
clavated or pedunculated ganglionic globule.*

Ley dig, an excellent observer, confirms the gen-
eral view here advanced of the direct connection
of the ganglionic globule with the nerve-tube ; see
loc. cit. p. 130, Taf. X. fig. 67 ( Piscico/a ). See
also Bruch , Siebold and Kb Hiker's Zeitsch. 1849,
p. 175, Taf. XII. fig. 7, 8, 9. — Ed.

158 THE ANNELIDES. § 148.

ring, and others with the cerebral ganglion by means of other small gan-
glia near the cephalic extremity.®

With the different orders and sub-orders of the Annelides, the nervous
system has the following modifications:

1. The Nemertini differ remarkably from the other Annelides in this
respect ; for their ventral cord is without ganglionic enlargements, and
composed of two separated cords, one on each side of the body, which
send off, right and left, lateral branches along their course. These two
cords arise at the anterior extremity in two ganglia blended together above
the oesophagus, which represent the cerebral ganglion, and send off many
nervous branches in front.®

2. With the Hirudinei, the ventral ganglia are much fewer than the
segments of the body, and are bound together by two contiguous cords.
The first and last of these ganglia are remarkable for their size. The first
sends filaments to the lips, the second to the caudal sucker.®

The Splanchnic system is composed of a small ganglion situated in front of
the cerebral one, and with which it is connected by two filaments. By its
side are two others, which are also small and connect with the cerebral by
delicate threads. All three send branches to the oral parts, while a deli-
cate filament goes to the inferior surface of the intestinal canal, and repre-
sents an inner splanchnic nerve.®

3. The ventral medulla of the Lumbricini consists of two nervous cords

1 Brandt , Bemerkungen fiber die Mundmagen-
oder Eingeweide-nerven der Evertebraten. Leipzig
1835, p. 37.

2 Rathkt (Danzig. Schrift. loc. cit. p. 100, Taf.
VI. fig. 10, 11) has thus described the nervous
system of Borlasia striata.

He has seen particularly two pairs of cephalic
nerves arise from the cerebral ganglion. One and
the larger of these is principally distributed to the
respiratory fossae of the head, while the other, the
smaller, passes directly in front, probably for the
vermiform organ upon the cephalic extremity.
Or s ted (Besehreib. d. Plattw firmer loc. cit. p. 5,
18), appears to be wrong in suspecting that Rathki
has taken the vascular for the nervous system, for
Quatrefages (Icon, du ll^gne anim. de Cuvier.
Zoophytes, PI. XXXIV. fig. 1) has figured by the
side of the vascular system, the nervous system of
Nemertes Camillae , exactly as it is described by
Rathke.

* [ § 148, note 3.j Leydig (loc. cit. p. 129) has
found the structure of the cerebral nervous centre
of Piscicola , quite different from that as described
by Leo. The cerebral mass is composed of cap-
sules containing ganglionic globules 5 these cap-
sules are symmetrically situated on each side of
the median line, but are connected by a well-
marked transverse commissure composed of nerve-
fibres ; see Taf. X. 67, 68, 69. See also upon the
nervous system of the Leeches, Bruch (Ueber
das Nervensystem des Blutegels : Ein Beitrag zur
topographischen Histiologie des Nervensy stems,
in Siebold and K olliker’s Zeitsch. 1849, p. 164).
This memoir is principally histological, and bears
upon that disputed point, — the alleged direct con-
nection between the ganglion-corpuscles and the
nerve-fibres. It has, however, some topographical
anatomical details, and the accompanying figures
would make the whole subject very clear. — Ed.

3 See Brandt and Ratzeburg , Med. Zool. II. p.
250, Tab. XXIX. B . (Sanguis uga medicinalis ),
and Leo, in Muller’s Arch. 1835, p. 422, Taf. XI.
fig. 10 ( Piscicola geometra). Wagner has found
an arrangement quite different from the above, in
Pontobdella muricata (Isis, 1834, p. 131,
Taf. I. fig. 3). He saw here the ventral gan-
glia united by a single cord which sends off
from each side only a single nerve. This nerve,
after a short course, has a ganglion, and then
divides into lateral branches. According to Stan -
nius , these lateral branches are not united together
by longitudinal cords as is the case with the Am-
phinome.*

4 See Brandt , Med. Zool. II. p. 251, Tab. XXIX.
B. fig. 7, and, Bemerk. fiber die Mundmagennerven
loc. cit. p. 39 ( Sanguisuga medic inalis).\

t [§ 148, note 4.] See, for some further remarks
on the Splanchnic system of the Hirudinei and
Lumbricini, Quatrefages , Ann. d. Sc. Nat. VIII.
1847, p. 36. According to him that of the Hiru-
dinei resembles that of the Insects, and is com-
posed of a chain of ganglia from which pass off
filaments, some to the abdominal chain, others to
the jaws, and others still to the walls of the oesoph-
agus. There is also a frontal ganglionic chain
which forms in front a real arcade, and from which
filaments are given off anteriorly.

With the Lumbricini it is considerably different,
and he thinks unlike that which has yet been
described of all the other Annelides.

See further, Ann. d. Sc. Nat. XIV. 1850, p. 282.
and XVIII. 1852, p. 167.

See also Ley dig, Siebold and Kblliker’s Zeitsch.
III. lift. 3, p. 315, and Quatrefages , Ann. d. Sc.
Nat. XVHI. 1852, p. 316 (Branc hellion).— Ed.

$ 148.

THE ANNELIDES.

159

which are nearly blended together into one, and whose closely-successive
ganglia correspond numerically with the segments of the body.®

4. With those Chaetopodes which have external branchiae, the nervous
system is most highly developed, but has wide variations as to its whole or its
details, according to the more or less complicated structure' of the cephalic
extremity and segments of the body. With those species which are without
antennae and eyes, the ventral medulla is composed of two contiguous
cords the enlargements of which are indistinct and not sharply defined. <B)
These two cords are separated at the cephalic extremity, and terminate
either, by a ganglion on each side without apparently forming by a commis-
sure an cesophageal ring,<7) or by encompassing the oesophagus, and forming
a ring through a ganglion lying upon it.(8)

With some, the two parallel cords- are without ganglia but are reunited
at each segment of the body by two transverse threads.® With others,
this connection occurs through transverse threads and ganglia. (10) There
are many Branchiati with which the two cords are so closely contiguous
that they are separated only by a longitudinal furrow. Their round or
elongated ganglia are then common, and succeed each other at longer or
shorter intervals.™ With an entire series of the Dorsibranchiati, the
ventral ganglia are so closely approximated that the interganglionic cords
appear wholly wanting.™

The brain is composed of only two ganglia, which are more or less blended
into one with the Gapitibranchiati, and with those Dorsibranchiati whose
head is very slightly developed ; u3) while with the other Dorsibranchiati
whose head is distinct and the eyes and tentacles very much developed, it
is the product of the fusion of many ganglia. <14)

5 See Gruithuisen , in the Nov. Act. Acad.
XIV. 1828, p. 412, Tab. XXV. fig. 3-5 (Chaeto-
gaster diaplianus ) Henle , in Muller's Arch.
1837, p. 85, Taf. VI. fig. 2, 3, 8, x, y ( Enchi -
traeus) ; Roth, De Animalium invertebratorum
systemate nervoso. Wirceburg, 1825, fig. 3 ; and
Morren , loc. cit. p. 117, Tab. XIX.— XXIII.
( Lumbricus terrestris).

In the common Lum bricus, two pairs of nerves
( Nervi annulares ) pass off laterally from the cen-
tre of the ganglionic enlargements ; and between
every two ganglia, exceptionally, there passes off
another pair (Nervi inter annulares) which are
distributed to the transverse muscular septa ; see
Morren loc. cit. The nervous system of Sternas-
pis thalassemoides i3 quite different, and appears
retrograded to the type of that of the Sipunculidae,
for the ventral medulla consists only of a simple
cord which is enlarged at the caudal extremity j
see Will, in Muller's Arch. 1842, p. 427.

6 Arenicola , Ammotrypane , and Terebella.

7 Arenicola ; see Grube , Zur. Anat. d. Kiemen-
wiirmer, p. 17, Tab. I. fig. 7 and Stannius , in
Muller's Arch. 1840, p. 379, Taf. XI. fig. 15.

8 Ammotrypane ; see Rathki, in the Nov. Act.
Acad. XX. p. 197, Tab. X. fig. 14, 19.

9 Sabella ; see Wagner , Isis, 1832, p. 657, Taf.
X. fig. 14 5 and Grube , Zur. Anat. d. Kiemenwur-
mer, p. 30, Taf. II. fig. 16.

10 Phyllodoce. Here, the transverse threads
commence only at the border of the 7ll» or 9lh gan-
glion. They alternate regularly with these and
disappear towards the last segments of the body ;
see Quatrefages, Ann. d. Sc. Nat. II. 1844, p. 95,
PI. If. fig. 2, 3.

11 Siphonostomum , Amphitrite , Amphinome ,
Aricinella , Polynoa , and Aphrodite. With Si-

phonostomum, the ventral ganglia are very long ;
see Rat like, Danzig. Schrift. loc. cit. p. 90, Taf. VI.
fig. 3. Here, the peripheric nerves are given off
from the interganglionic cords and not from the
ganglia themselves.

With Amphitrite , the ventral ganglia are long
also, but from the fifth segment of the body they
alternate with others that are round, so that each
segment has two ganglia. Both of these ganglia
furnish exclusively the peripheric nerves, but in
front where the round ganglia are wanting, they
are furnished also by the interganglionic cords ;
see Rathki f, loc. cit. p. 75, Taf. V. fig. 7, 15. With
Aricinella ( Quatrefages , loc. cit. p. 96, PI. II.
fig. 5), and Amphinome ( Treviranus , Beobacht.
aus d. Zoot. u. Physiol. 1839, p. 83, Taf. XI. fig.
72), the ganglia are very closely set together. With
Aphrodite , and Polynoe , the number of ventral
ganglia exceeds that of the segments of the body ;
see Grube , loc. cit. p. 66.

12 Nereis , Eunice , Glyccra ; see Wagner , in
Isis, 1834, p. 133, Taf. I. fig. 11 ; Muller , in the
Ann. d. Sc. Nat. XXII. 1831, p. 22, PI. IV. fig. 10 *,
Rathki , De Bopyro et Nereide p. 41, Tab. II. fig.
13 Grube , Zur. Anat. d. Kiemenw firmer, p. 43,
Taf. II. fig. 9 ; and Quatrefages , Ann. d. Sc.
Nat. loc. cit. PI. I. fig. 1, 2, 3.

13 Amphitrite, Siphonostomum (Rathki, Dan-
zig. Schrift. loc. cit. Taf. V. fig. 7, 14, Taf. VI. fig.
3), and Glycera (Quatrefages, Aim. d. Sc. Nat.
loc. cit. p. 96, PI. I. fig. 3)/

H Nereis, Eunice, and Phyllodoce ; seeil ful-
ler, Ann. d. Sc. Nat. loc. cit. PI. IV. fig. 10 -,
Rathki, De Bopyro et Nereide, p. 43, Tab. II. fig.
4, 5, 13 -, and Quatrefages , loc. cit. p. 81, PI. I.
fig. 1, 2, PI. II. fig. 1.'

* [§ 148, note 13.] See Quatrefages, Ann. d. Sc. Nat. X. 1848, p. 47 ( Hermella ), and XII.
1849, p. 300 ( Chloraema ). — Ed.

160

THE ANNELIDES.

$ 149.

With the Dorsibrancbiati, the many delicate threads which arise from
the cerebral ganglion by special roots and pass to the different portions of
the digestive canal with a ganglion here and there upon their course, may
be regarded as splanchnic nerves. (15>

With the Amphinomae, Euniceae, Nerei'deae and Ariciae, there arise
from the posterior border of the cerebral ganglion two roots which may be
regarded as Nervi pkaryngei superiores, and which unite near their origin
into a Ganglion pharyngeum superius. From this last pass off posteriorly
delicate threads which form many ganglia upon the oesophagus, and after-
wards spread over probably many other parts of the digestive canal.

Beside this Plexus splanchnicus superior, there is sometimes a Plexus
splanchnic//, s inferior — formed by other roots which pass off inferiorly
from the brain ; part of these form under the oesophagus a Ganglion pha-
ryngeum inferius, while others, passing backwards, constitute Nervi pha-
ryngei and cesophagei. aG>

The Amphinomae have on each side of the abdomen a very remarkable
ganglionic chain. Their ganglia intercommunicate, not only by longitudinal,
but also by transverse anastomoses, with the central mass of the nervous
system. Among these last, those which are given off from the anterior
lateral ganglia, join the connecting filaments of the oesophageal ring ; while
the others, arising from the posterior lateral ganglia, go to the various
ganglionic enlargements of the ventral cord.(17>

It has not yet been possible to ascertain the signification of these lateral
ganglionic chains.

CHAPTER IV.

ORGANS OF SENSE.

I. Organs of Touch.

§ 149.

With the Annelides, the sense of touch is particularly developed at the

cephalic extremity.® With some Li
into a kind of tentacular proboscis.®

15 Cuvier (Le<j. d’Anat. Comp. II. 337) has no-
ticed with Aphrodite two nerves passing back-
wards which ought to be regarded as of a splanch-
nic nature ; but Grube (Zur. Anat. d. Kiemen-
w firmer, p. 58) has been unable to find them even
in the same species.

16 Stannius (Isis, 1831, p. 986, Taf. VI. fig. 8, r.
r.), and Grube (De Plelone carunculata, 1837, p 9,
fig. 5, r.), have seen with certain speeies of Amphi-
nome the two roots of the Plexus splanchnicus
superior , but were unable to trace them further.
However, with Eunice Harassii , Grube (Zur.
Anat. d. Kiemenwiirmer, p. 43, Taf. II. fig. 9, i.) has
found beside these two roots, the Ganglion pharyn-
geum superius which they form, and the nervous
filaments which pass off from this last. Quite lately,
Quatrefages has given very exact and detailed
descriptions and figures of the expansions of the
Plexus splanchnicus superior and inferior , with
Eunice Nereis, Glycera , Phyllodoce , and Arici-
nella ; see Ann. d. Sc. Nat. 1844,11. p. 81, PI. I. II.

unbricini, this extremity is prolonged
The Branchiati have special and

17 These two ganglionic chains were first de-
scribed by Stannius with Amphinome rostrata
(Isis, 1831, p. 986, Taf. VI. fig. 4). He saw three
ganglia connect with the oesophageal ring on each
side. But Grube (De Pleione carunculata, p. 10,
fig. 5) has seen six on each side with Amphinome
carunculata. These lateral ganglia, moreover,
remind one of those described by Wagner , as al-
ready noticed with Pontobdella muricata.

1 According to Rathki (Danzig. Schrift. loc. cit.
p. 94, 100), the two cephalic and respiratory fossae
with the N emertini, are the seat of a most delicate
sense of touch and their white, long and protrac-
tile proboscis is also a tactile organ. But other
naturalists attribute wholly different functions to
these organs.

9 The proboscis is non-articulated with Nals pro-
boscidea , and Euaxes jiliformis {Grube, Wieg-
jnann's Arch. 1844, I. p. 204, Taf. VII. fig. 1).
But it is articulated with Rhynchelmis {Hoff-
meistcr , Ibid. 1843, 1. p. 192, Taf. IX. fig. 8).

§ 150.

THE ANNELIDES.

161

often very prominent tactile organs, in the form of processes of variable
number and shape, which are situated principally though not entirely upon
the cephalic extremity of the body. Those upon the head have been
named Antennae , and the others Cirri. These last are often very numer-
ous upon the first segment of the body. Both are contractile and usually
unarticulated, though sometimes having very distinct joints.® The an-
tennae receive their nerves directly from the cerebral ganglion/4’ while
those of the cirri of the first segment, are given off from the base of the
two lateral cords of the oesophageal ring, and from the first ventral gan-
glion/5’

II. Organs of Vision.

§150.

With nearly all the Capitibranchiati/” and with many Nemertini, and
Lumbricini, the eyes are wanting. But, as visual organs, have been re-
garded the brown or black dots, which are two in number with many Nais,
four with Tetrastemma, but are innumerable and arranged irregularly or
in rows upon the neck, with Polystemma and Nemertes. But these are
scarcely more than simple pigment dots/2’

With the two to ten eye-specks of the Hirudinei/3’ however, the structure
is quite different. Here the eye(4) is composed of a transparent cylindrical
body, a little attenuated and rounded at its inferior extremity, while the oppo-
site one causes the skin to bulge out like a cornea. Its remaining portion is

3 The antennae of the Annelides have been dis-
tinguished from those of insects by being termed
Tentacula ; for they are non-articulated, while
those of insects are articulated. But this distinc-
tion is not valid, for, with the Branchiati, there are
insensible transitions from the non-articulated ten-
tacula to the articulated antennae. But another
and more essential difference is, tifat those of the
Annelides are contractile, while those of insects are
not. These organs are articulated with Eunice ,
Peripatus , and Syllis. In this last it is true of
the cirri also. The modifications and varieties of
the antennae and cirri belong, however, to the
province of Zoology.

4 With Nereis , four nerves pass off from the
anterior portion of the brain to the four antennae *,
the two external as gustatory nerves and which go
to the larger antennae, are largely swollen at their
extremity *, see Ralhkt, De Bopyro et Nereide, p.
43, Tab. II. fig. 4, 5.

3 See Rathki , Ibid. Taf. II. fig. 18, d. d. and in
the Danzig. Sehrift. loc. cit. p. 70, Taf. Y. fig. 14,
d. d.

l A remarkable exception to this occurs with
Amphicora Sabella as described by Ehrenberg
(Mittheil. aus d. Verhandl. d. Gesellsch. naturf.
Ereunde zu Berlin, 1836, p. 2). It has, it would

* ( § 150, note l.| Quatrcfages (Ann. d. Sc.
Nat. X. 1848, p. 48, PI. II. fig. 10, y.) describes
two colored points situated on the middle of the
brain of Hermella , as eyes. They are composed
of pigment and rest directly on the nervous sub-
stance. — Ed.

t [ § 150, note 2.] Quatrefages (Compt. rend.

14*

appear, two eyes not only at the cephalic extremity,
but at the opposite one also.*

2 Gruilhuisen (Nov. Act. Acad. Nat. Cur. XI. p.
242) has described the two eyes of Nais probosci -
dea as particles of pigment enveloped by a sensi-
tive parenchyma. But this is not based upon ob-
servation, and is an hypothesis only, as Muller
has very judiciously remarked (Ann. d. Sc. Nat.
XXII. 1831, p. 20). The assertion of Quatrefages
is of more weight (Comp. rend. XIX. 1844, p. 195).
He affirms that the pigment specks of many Ne-
mertini and of amarine species allied to Nais, con-
tain really light-refracting bodies, and connect
with the nervous centre by particular nerves.
The last of these Annelides has similar pigment
specks also upon each side of the segments of the
body, which receive each a distinct nerve from the
ventral marrow. Is not this species identical with
the Nais pictn described by Dujardin (Ann. d.
Sc. Nat. 1839, XI. p. 293, PI. VII. fig. 9) ? t

3 Clepsine has two, four or six eyes •, Nephelis,
eight *, and Haemopis and Sanguisuga, ten ;
while with Brnnchiobdella , they are wanting.
With this family (the Hirudinei), these organs are
always symmetrically arranged upon the neck.

4 At least with Sanguisuga officinalis.

Dec. 31, 1849) has found very perfect eyes with
Torrea vitrea , consisting of a crystalline lens, a
choroid coat, a vitreous humor, a transparent cor-
nea, &c. He thinks also that he has discovered,
with Sabella eyes situated on the branchiae • —
Ed.

162

i

§ 151.

THE ANNELIDES.

enveloped with a layer of black pigment.® Each of these bodies receives
a nervous filament from the cerebral ganglion. Undoubtedly, these fila-
ments are optic nerves, and the cylindrical bodies are light-refracting and
1 ight-con cent rat ing organs. (6>

Many of the Dorsibranchiati are entirely without eyes, having only the
eye-specks ; but others, belonging to the Amphinomae, Nereideae, Euniceae,
and Aphroditae, have two to four very distinct eyes.® In these, there is
an eye-ball invested with a black or brown pigment layer : and this layer
often has, above, a very distinct round pupillary opening, covered by the
skin, which bulges out like a cornea. At the central portion of this
layer, there is concealed a transparent body, which is very probably sur-
rounded by a retina-like expansion of the optic nerve. The optic nerves
which are given off usually from the upper surface of the brain have, after
a short course, and before entering the pigment layer of the eye, an enlarge-
ment. It is said that with some the light-refracting body and the pupillary
opening are wanting. In such cases, the eyes could only distinguish light
from darkness.®

III. Organs of Hearing.

§ 161.

Although it has never been doubted that the Annelides can perceive
sounds, yet it is of late only that the attention has been directed to the
locality of the auditory organs. The two vesicles, which, with some Chae-
topodes, are situated near the oesophageal ring, and contain crystalline
bodies, may be regarded as simple Vestibula , containing many otolites. (1)

5 Weber was the first to show that the black
specks of Sanguisuga officinalis were really eyes
(Meckel's Arch. 1827, p. 301, Taf. III. fig. 24).
This has been confirmed by Brandt (Med. Zool. i.
p. 251, Taf. XXIX. A. fig. 10-12), and more re-
cently, Wagner has discovered in the interior of
the pigment layer, a transparent body, composed,
he thinks, of two parts, a crystalline lens and a vit-
reous portion ; see Wagner , Lehrbuch, d. ver-
gleicli. Anat. 1835, p. 428 ; also Lehrb. d. speziellen
Phys. 1843, p. 383, and, Icon, physiol. 1839, Tab.
XXVIII. fig. 16.

6 Brandt has been able to trace the ten optic
nerves of Sanguisuga officinalis from the brain
even to the eyes (Med. Zool. loc. cit. p. 250, Taf.
XXIX. B. fig. 2).*

7 With Glycera , Aricia , Arenicola , and Cir -
ratulus , the eyes are wanting. With Goniada ,
and Nephtys , there are only simple pigment specks
upon the head. With Eunice , Phyllodoce , and
Alciopa . there are two eyes ; and four with Nereis ,
Syllis , Hesione , and Amphinome. The genus Al-
ciopa is well suited, from its large size, for the dissec-
tion of these organs.

& For a most detailed description of the eyes of
Nereis, we arc indebted to Muller (Ann. d. Sc.
Nat. XXII.. 1831, p. 22, PI. IV. fig. 6 10), and Wag-

* [ § 150, note 6.] For further details on the ocu-
lar organs of the Hirudinei, see Moquin-Tandon ,
loc. cit. Ed. 1846, p. 80, PI. VIII. fig. 11. Accord-
ing to him, they contain neither a lens nor a vitre-
ous humor, and are only light-perceiving organs.
Bee also Ley dig (loc. cit. p. 129) who makes the
following statement upon the nature of these bodies

ner (Lehrb. d. Physiol, p. 383, and Icon, physiol.
Tab. XXVIII, fig. 15). Wagner , who, formerly
(Zur vergleich. Physiol, d. B lutes, 1833, p. 55),
could not, any more than Muller, perceive the
light-refracting body, has at last seen it distinctly.
For my own part, I can confirm its presence in the
two eyes of Eunice gigantea , which have a circu-
lar pupil. According to RathkC (De Bopyro et
Nere'ide, p. 44, Tab. II. fig. 4, 5) the eyes of Ne-
reis pu/satoria and lobu/ata want the pupil,
although it is present with those of Nereis Dumer-
ilii. According to Wagner , the pupil is wanting
with the two posterior eyes, but is present with the
two anterior ones, with most of the Nereideae.

1 I have compared the swellings noticed upon the
oesophageal ring of Arenicola , by Grube and Stan-
nius (see Wiegmann's Arch. 1841, I. 166), to the
auditory vesicles of Mollusks, and their contents to
otolites *, since then, Quatrefages has recognized
the presence of similar auditory organs containing
many otolites with two species allied to Amphicora
(Compt. rend. XIX. 1844, p. 195, and Ann. d. sc.
Nat. 1844, II. p. 94). Frey and Leuckart (Beitr.
&c. p. 81), after a very careful examination of the
organs of Arenicola , which I have regarded as au-
ditive, have confirmed this opinion.

with Piscicola : “They receive no nerve, neither
do they contain a light-refracting body. I regard
them as simple ornaments, wholly analogous to the
corresponding pigment dots on the pedal shield,
with which they also correspond in color and dis-
tribution.”— Ed.

$$ 152, 153.

THE ANNELIDES.

163

CHAPTER V.

DIGESTIVE APPARATUS.

§ 152.

The digestive canal of the Annelides, which is organized after very dif-
ferent types, opens always at the anterior part of the body by a mouth, and
at the posterior part by an anus. It is situated upon the axis of the body,
and is usually straight, rarely having convolutions. Often it is divided
into many sections, to which the names of pharynx, oesophagus, stomach, and
intestine, may be given. The mouth is usually surrounded with thick lips,
and, with many Capitibranchiati, it has very erectile tentacles and cirri,
which may be not only tactile but prehensile organs.™ With others of
this group, the food is taken in by the action in the water of the ciliated
branchial rays which surround the mouth in an infundibuliform or spiral man-
ner.™ Rut usually the food, both soft and solid, is seized by the protube-
rant lips, and swallowed by the very muscular pharynx. Many Annelides can
also suck in liquid food through their organs of deglutition.™ The stomach
and intestine is lined with ciliated epithelium. The intestinal canal, whose
walls are in general very thin, is either closely embraced by the parenchy-
ma of the body,™ or, when there is a cavity of the body, is supported and
constricted by numerous muscular septa.®

I. Organs of Deglutition and Mastication.

§ 153.

The mouth of the Nemertini is situated upon the ventral surface, and
usually at some distance from the cephalic extremity. It is a longitudinal
orifice opening into a long, muscular and very spacious pharyngeal tube.™
This tube is intimately united with the parenchyma of the body, and after
passing a short distance backward, joins directly with the intestinal canal.™
With many Hirudinei, the mouth is at the anterior extremity. Its ante-
rior border projects so as to form a kind of lip, which the animal can vol-

untarily change into a sucker. Other

1 Terebella , Amphitrite , and Siphonostomum.

2 Sabella , and Serpula.

3 Many Hirudinei.

4 This is true of the Hirudinei, and many Nemer-
tini.

5 With the Chaetopodes.

1 See Eelle Cliiaje , Memorie loc. cit. Tav.
LXXVIII. fig. 8. b. ( Folia genic ulata) ; Huschke ,
Isis, 1830, Taf. VII. fig. 2 ( Notospermus drepa-
nensis) ; Grube, Aktinien, Echinod. und Wurmer,
&c., loc. cit. fig. 7, a. ( Meckelia annulata ) ,• Rat/i-
k<l, Danzig. Schrift. loc. cit. Taf. VI. fig. 8. b. (Bor-
lasia striata ) ; and Ehrenberg, Symbol. Physic.
Phytozoa Turbellaria, Tab. IV. fig. 4. g. ( Micrura
fasciolata). Ehrenbers, ’, moreover, was deceived
in regarding this mouth as the opening of the gen-
ital organs, and in taking the proboscideal organ of
this species, for the true mouth. There is yet in
this respect much contradiction among naturalists.

species have a complete oral sucker,

Thus Dugds, with Polystemma (Prostoma) arma-
turn (Ann. d. Sc. Nat. XXI. 1830, p. 74, PI. II.
fig. 5), and Quatrefuges, with Nemertes man-
dilla (Icon, du Il^gne anim. de Cuvier, Zooph. PI.
XXXIV. fig. 2), regard the long canal which opens
at the cephalic extremity, as the pharyngeal tube,
and the spines at its base as masticatory organs j
while Orsted (Beschreib. d. Platt w firmer, p. 22,
Taf. III. fig. 41, 49, 50) regards this whole appa-
ratus with Tetrastemma as a copulatory organ
(see below). In my opinion, the animals here cited
do not belong even to the Nemertini.

2 Borlasia ( Rathki , loc. cit. p. 96, Taf. VI. fig.
10, 11) and Polia ( Delle Chiaje, loc. cit. II. p.
407, Tav. XXVIII. fig. 3, j., or Isis 1832, p. 648,
Taf. X. fig. II. 3, j ). With Meckelia annulata, 1
have found the pharyngeal tube arranged in the
same way.

/

164

THE ANNELIDES.

§ 154.

entirely distinct from the rest of the body.® These suckers serve not only as
locomotive organs, as the one, for instance, which is situated at the posterior
end of the body, but also for the drawing in of liquid food, and particularly
blood. For this purpose; many Hirudinei have a short and spacious^pha-
rynx, possessed of muscular walls, which are blended with the parenchyma
of the body, and which are armed with horny teeth, by which they cause
the wounds necessary for sucking the blood. With Branchiobdella, the
pharynx has horny upper and lower jaws, of a pyramidal form.® With San-
guisuga, and Haemopis, on the contrary, the base of the pharynx has three
fleshy swellings, the projecting arciform border of which is edged with bicus-
pid teeth.® In this respect, Clepsine is quite different. The pharyngeal
tube is very long, and from its base a movable fleshy tube can be protrud-
ed out of the mouth, and which the animal can use as a proboscis.® With
the Abranchiati, and Capitibranchiati, the pharynx is simple, short and
muscular, and presents nothing remarkable. With the Dorsibranchiati, if
is very muscular, of variable length, and stretches freely into the cavity of
the body. By the aid of special muscles, it may be folded upon itself, and
project far out of the mouth.® With many Annelides, the pharynx has a
horny, masticatory apparatus of sometimes a very complicated structure,
and which, when the pharynx is protruded, often extends out beyond it, and
serves as a prehensile organ.® These two, four, seven, eight or nine jaws
always move laterally upon each other. They are usually curved like
hooks, and denticulated upon their concave side. When numerous, they
are of dissimilar forms with the same individual.®

II. Intestinal Canal.

§ 154.

The intestinal canal of the Nemertini passes directly from the mouth to
the anus, without forming a stomachal dilatation. Its walls are closely
•united with the parenchyma of the body, audits internal surface throughout
is thickly set with annular folds, which, projecting far into the canal, form
there pouch-like divisions. (1)

3 Pise? coin, and Pontobdella.

4 See lienle , Muller's Arch. 1835, p. 575, Taf.
XIV. fig. 1.

5 See Moquin-Tandon, Monog. des Hirud. p.
43, PI. I. fig. 2. 11, PI. IV. V. ; Brandt, Med. Zool.
U p. 245, Taf. XXIX. A. fig. 13-18, 21, Taf.
XXIX. B. fig. 13-17. The swellings of these
leeches are carried in front during suction, so as
to resemble a three-rayed star — the form of the
wound which they produce.

6 See Moquin-Tandon, loc. cit. PI. IV. This
proboscis quite reminds one of the pharyngeal tube
of the Planar iae, which also can be protruded from
the mouth, but without being reversed.

7 This pharyngeal tube is short with Amphi-
nome, Nereis , Eunice, and Peripatus ; but very
-long with Aphrodite, Polynoc, Hcsione, Phyllo-
dor.e , Glycera, and Goniada ; see Audouin and
Milne Edwards, Recherches, &c.,loc. cit. That of
Aphrodite , Polynoe , Amphinome , and others,
has been regarded as a stomach ; see Treviranus .
in Tiedemann's Zeitsch. f. Phys. III. p. 161. Taf.
XII. fig. 9. 10, k *, Grube , Zur Anat. d. Kiemen-
wiirmer p. 54, et seq. and Stannius , Isis, p. 982.
But the position, structure and muscular appara-

tus of this organ are against this view, and quite in
favor of its being a pharynx.

8 The jaws are wanting with Amphinome, Phyl-
lodoce, Aricia, Chaetopterus , and Arenicola.

9 There are two strongly-curved jaws with Ne-
reis, Lycastis, and Peripatus ; four with Polynoil ,
Aphrodite, and Glycera ,• and eight with Lumbri-
nereis. Of the seven with Eunice , there are
four, one on one side, and three on the other. The
same asymmetry exists with those of Aglaura ami
Oenone ; see Audouin and Milne Edwards, Re-
cherches, &c., loc. cit.

1 According to Rathki (Danzig. Schrift. loc. cit. p.
96), these transverse folds do not exist with Borlasia
striata , except when the body is shortened by con-
traction, and they disappear when it is again extend-
ed. But it did not appear thus to me with the nu-
merously folded intestine of Meckelia annulata.
Delle Chiaje had already observed these folds
with Polia sipunculus, but figured them as iso-
lated pouches (Memorie, loc. cit. II. p. 407, Tav.
XXVIII. fig. 3, 6, or Isis, 1832, Taf. X. fig. II. 3,
4). According to Quatrefagcs (Ann. d. Sc. Nat.
VI. 1846, p. 243), the intestinal canal of the
Nemertini. which occupies the axis of the body.

}

$ 154.

THE ANNELIDES.

165

With the Hirudinei, the intestinal canal varies very much, especially as
to the number and volume of its appended coeca/2' Its very narrow anal
opening is upon the back directly above the pedal sucker.® With Nepke-
lis, the canal is simple and gradually enlarges from before backwards, but
has no coeca.

With Branchiobdella , it is deeply constricted in several places.® With
Pontobdella, it is simple with its two anterior thirds, but there is a caecum
on each side of its remaining portion.® This last is also true of its posterior
third with Haemopis, Clepsine, and Sanguisuga.{6) With this last genus,
the other portions of the canal are divided by ten or eleven constrictions
into as many parts which send oil’ on each side short caeca; (,) while that
of Clepsine has on each side five or six coeca, all of which may be rami-
fied. There is a kind of valve directly behind the last two caeca, and so,
the part of the intestinal canal in front of this may be regarded as a stom-
ach and a small intestine, while the remaining portion behind it, represents
the rectum.*'

With the Abranchiati, the intestinal canal is short, and its oesophagus '
which is usually narrow passes into a muscular pharynx, which leads into
a stomachal dilatation. Upon these parts follow the remaining portions of
the intestine which are separated from each other by the transverse septa
of the body and often resemble the stomach. With a few species only, the
stomach is remarkable for its thick, muscular walls.®

With some of the Capitibranchiati, the digestive canal arises directly
behind the oesophagus and has bulging portions like those of the colon/®
assuming, posteriorly, sometimes a spiral form.(11) With others, the oesoph-
agus is continuous directly into the intestinal canal, which, free and un-
attached by diaphragmatic septa, makes many turns in the cavity of the
body, and by constrictions is divided into a stomach, small intestine, and
rectum/12'

With many Dorsibranchiati, the intestine follows directly upon the
oesophagus, and is either straight and divided by constrictions/18' or assumes
a spiral form114' or is without constrictions and irregularly tortuous/®
With others, the portion of intestinal canal between the pharynx and in-

forms with the buccal orifice, a cavity distinct from
that of the abdomen, and its anus has a kind of
sphincter. But this is certainly an erroneous view
of the organization of these worms : the contents
of the cavity are sufficient alone to confute it.

2 Moquin-T andon, loc. cit. PI. I. -IV.

3 With Piscicola , exceptionally, the anus is up-
on the ventral surface of the last segment of the
body •, see Leo, in Muller'1 s Arch. 1835, p. 420.

4 Uenle, Muller's Arch. 1835, Taf. XIV. ti g. 1.

5 Wagner, Isis, 1834, p. 130, Taf. I. fig. 1, 2.

G Brandt and Ratzeburg, Wed. Zool. II. p. 246,
Taf. XXIX. B. fig. 12.

7 Ibid. -Taf XXIX. A. fig. 19, 20, 55.

8 With Clepsine mar ginata, this rectum has
coecal appendages also *, see F . Muller , in Wieg-
tnann's Arch. 1844, I. p. 371, Taf. X. fig. 14.*

9 With Lumbricus , the stomach is very muscu-
lar ; see Morren , loc. cit. Tab. XI.-XIV. This is
also true of Na is proboscidea, but not with Lum -
briculus , and Enchitraeus.

* ( § 154, note 8.] For many special details
illustrating as well the histology as the anatomy of
the intestinal caDai of the Hirudinei { Piscicola,

10 Terebella , and Sabella ; see Grube , Zur
Anat. d. Kiemenw ii rmer, p. 20, 27, Taf. II. fig.
12, and Milne Edwards, Ann. d. Sc. Nat. X.
1838, PI. X. XI.

11 Sabella ,* see Cams and Otto, Erlauterungs-
taf. lift. IV. Taf. III. fig. 4, 6, and Wagner, Icon,
zoot. Tab. XXVII. fig. 21.

12 Amphitrite, and Sip/innostojnum. With the
first, the stomach is long, spiral, and divided into
an ascending and a descending portion ■, see Rath -
k<[, Danzig. Schrift. loc. cit. p. 64, 86, Taf. V. VI.

13 Amphinome, Arenico/a, Eunice, and Neph-
tys ; see Stannius , Isis, 1831, Taf. VI. fig. 10 j
Milne Edwards, Ann. d. Sc. Nat. X. 1838, PI.
XII. XIII. ; Grube, Zur Anat. d. Kiemenw ii rmer,
Taf. I.

14 According to Grube (Ibid. p. 34), the intes-
tine of Cirratulus is spiral like that of Sabella.

15 Ammotrypane (according to Grube, see
Rathfce , Nov. Act. Acad. Nat. Cur. XX. p. 197,
Tab. X. fig. 13).

Clepsine , Nephelis ), see Ley dig, loc. cit. p. 110,
Taf. VIII. IX. fig. 24-37. — Ed.

166

THE ANNELIDES.

§ 155.

testine, receives the excretory ducts of glandular appendages and is there-
fore, more properly a stomach than an oesophagus. <16) With many, the
stomach and its appendages are wanting, but then the entire canal stretch-
ing directly across the cavity of the body has on both sides long analogous
appendages which sometimes consist of dilated sacs, so that the.se append-
ages have wholly the aspect of caeca. <17>

III. Glandular Appendages.

§ 155.

The glands appended to the digestive canal of the Annelides may be di-
vided into the salivary and hepatic organs. The first of these are some-
times absent, but the last are never wanting.

The organs regarded as salivary glands are attached either, to the pha-
rynx or to the beginning of the intestinal canal. With the Nemertini,
they are absent. But with Sanguisuga, as abdominal salivary glands,
may be regarded the many groups of round corpuscles which surround the
commencement of the intestine, and whose excretory ducts open into it by
many orifices, after anastomosing together.® With Lumlricus , there is
a long lobular body on each side of the pharyngeal tube which secretes a
whitish liquid, and which is analogous perhaps to an oral salivary gland. <2)
The four pairs of transparent vesicles, which, with Enchytraeus, open afc
the inferior extremity of the oesophagus, are possibly of the same nature.®
With Siphanostomum, there are two riband-like caeca which pass along the
oesophagus and open separately into the oral cavity.® With many Dorsi-
branchiati, the commencement of the intestine has two glands of probably
a pancreatic nature.® It is difficult to decide as to the hepatic or sali-
vary nature of the numerous and usually white appendages, which belong
to both sides of the whole alimentary canal of the Aphroditae. With Pol-
yno'c, these consist of six cylindrical, caecal, and sometimes bifid tubes,
lying between the muscles of the walls of the body.®

With Aphrodite hystrix, there are twenty of these tubes on each side

10 Nereis ; see Rathk.6 , De Bopyro et Nereide p.
35, Taf. II. fig. 7, 8.

17 With Aphrodite hystrix , and aculeata , the
intestine has on each side twenty glandular append-
ages with long peduncles. In this last species,
these appendages are caeca also, for they have at
their extremities saccular dilatations filled with
chyme •, see Pallas , Miscell. Zool. p. 85, Tab. VII.
fig. 11 ; Treviranus , in his Zeitsch. f. Physiol.
III. p. 162, Taf. XII. fig. 9, 10 •, and Milne Ed-
wards, in Cyclop. Anat. and Phys. I. p. 169, fig.
70.

1 Brandt , Media. Zool. II. p. 247. Taf. XXIX.
A. fig. 22, 23*

2 Morreii, loc. cit. p. 129, Tab. X. XI. ( [Lum -
bricus terrestris).

3 Henle , in Muller's Arch. 1837, p. 79, Taf. VI.
fig. C, d. d.

* [ § 155, note 1.] For the salivary glands of
Hirudinei, 6ee Moquin-Tandon , loc. cit. Edit.
1846, p. 108, PI. X. fig. 4 ( Hirudo medicinalis ),
PI. VI. fig. 11 ( [Haemopis ), PI. I. fig. 5 ( Branch -
ellion). — Ed.

4 Rathke , Danzig. Schrift. loc. cit. p. 87, Taf. V»
fig. 5, c. c.

5 With Nereis , these two salivary glands com-
municate by two narrow ducts with that portion of
the intestinal canal which should be regarded as a
stomach ; see Rathke, De Bopyro et Nereide, p.
38, Tab. II. fig. 7, g. 8. Grube has found these
two appendages at the beginning of the intestinaR
canal with Arenicola (Zur Anat. d. Kiemenwur-
mer, p. 6, Taf. I. fig. 1, 5, h.), and with Ammotry-
pane (Nov. Act. Acad. XX. p. 197, Tab. X. fig.
13, 19, h.). See also Milne Edwards, in the Ann.
d. Sc. Nat. X. 1838, PI. XII. fig. 1, j. (Nereis), and
PI. XIII. fig. 1, e. e. (Arenicola) ; and fVagner *
Icon. zoot. Tab. XXVII. fig. 18, g. g. (Nereis).]

6 Grube , Zur. Anat. d. Kiemenwiirmer, p. 62*
Taf. II. fig. 13 (Polynoe squamata).

t f § 155, note 5.] For the salivary glands of
Branchellion , see Leydig , Siebold and Kblliker's
Zeitsch. III. lift. 3, p. 315, and Quatrefages , Ann.
d. Sc. Nat. XVIII. 1852, p. 296, PI. VI. fig. 3* a
c. — Ed.

§ 156.

THE ANNELIDES.

167

of the intestinal canal ; these are narrow and their botryoidal extremities
lie in the interstices of the dorsal wall of the body.

With Aphrodite aculeata , the structure is analogous but differs in that
these appendages have more the aspect of coeca with thin walls, and have
not the ramified diverticula except in their central part and between the
already-mentioned saccular dilatations. (7)

As an hepatic organ may be regarded with more certainty a particular
tissue colored in part brownish yellow, and partly greenish yellow, which
closely surrounds the whole intestinal canal of most Annelides. Carefully
examined, this tissue is found composed of closely-aggregated glandular
sacs which empty their contents into the intestine either directly, or by
many common excretory ducts. <a> This contained liquid is, with most
species a transparent fluid in which are suspended brown granules, and it
resembles the bile of the higher animals.

C II APT Ell VI.

CIRCULATORY SYSTEM.

§ 156.

This system is highly developed with the Annelides. The blood is usu-
ally colored, and the vascular system, remarkable for many peculiarities,
is complete and closed.

This system may be divided into a central and a peripheric part.

The first consists of large contractile vessels taking the place of a
Heart. There are also various heart-like organs in the shape of varicose
dilatations upon the course of the contractile vessels. The principal ves-
sels have a longitudinal course, occupying the whole length of the median
line of the body, — one as a dorsal, and the other as a ventral vessel.

With many Hirudinei, there are also lateral vessels. The dorsal and
ventral vessels unite at both extremities, beside anastomosing by transverse
branches in the separate segments.

When there are lateral vessels, these also connect with the median ves-

7 See Pallas, Trcviranus , Milne Edwards ,
loc. cit., and Grube, loc. cit. p. 54.

& According to Henle ( Muller's Arch. 1837, p.
81, Taf. VI. fig. 2), this glandular envelope forms a
villous envelope about the intestine. This is also
true of Lumbricus , Lumbriculus , Nais, and
Chaetogaster. The glandular sacs are greenish
with Branchiobdella ( Henle, loc. cit. 1835, p. 575),
yellowish with Amphitrite ( Rathki , Danzig.
Schrift. loc. cit. p. 65). With Sanguis uga, the ex-
cretory ducts of the hepatic sacs inter-anastomose
and form a kind of net-work around the stomach
and its coeca 5 see Brandt , Med. Zool. p. 247, Taf.

* { § 155, note 8.] The hepatic organs with the
Annelides have been successfully studied by Will
( Muller's Arch. 1848, p. 508), who has used chem-
ical tests. lie has found the glandular layer

XXIX. A. fig. 28, 29. With many, this hepatic
layer envelops also the blood-vessel upon the dorsal
surface of the intestine. It is passible that the
yellow canal described by Morren , with Lumbri-
cus terrestris as Chloragogena, is only this hepat-
ic mass (loc. cit. p. 142, Tab. XV. XVI.). Another
canal which is traversed by blood-vessels and closed
at both extremities, and which is contained in a
longitudinal enlargement upon the internal sur-
face of the intestinal canal, and is called by Mor-
ren , Typhlosolis (loc. cit. p. 13S, Tab. XI. XII.
XVI. XVII.) may perhaps be regarded as a recep-
tacle of chyle.*

( Lumbricus , Nais), and the long, thread-like and
coecal glands ( Hirudo , Haemopis , Aulacostoma,
Jfelluo , Piscicola , Clepsine ) which surround the
intestinal canal, to be organs of this nature. — Ed.

168

THE ANNELIDES.

§ 157.

eel by transverse anastomoses. The peripheric vessels arise by means of a
capillary net-work, from the most various points of the longitudinal and
transverse vessels. The circulation has on the whole a determinate direc-
tion,— the dorsal vessels force by a kind of peristaltic movement the
blood from behind forwards into the ventral vessel, which returns it
into the dorsal vessel. The blood can, however, pass from the dorsal
to the ventral vessel by a much shorter way, — by traversing the
capillaries, or directly through the transverse anastomoses. It is, more-
over, very probable that the course of the blood in the transverse vessels
is not always in the same direction, and that it may under certain circum-
stances pass from the ventral into the dorsal vessel. This makes it difficult
to decide which of these vessels are arteries, and which veins. The respir-
atory organs, which usually form the limit between the venous and arterial
systems, are, with most Annelides connected with the transverse vessels,
and therefore throw no light upon this doubtful point. From the multitude
of these transverse anastomoses, it must appear impossible to distinguish
the arterial from the venous blood, and the distinction of veins from arte-
ries with most Annelides must be wholly arbitrary.

The blood of the Annelides, although red like that of the vertebrates,
is, however, quite different. It is composed of a liquid containing glob-
ules. These last, which are always colorless, of unequal size, and of a
spherical form, are granulated on their surface. a) The blood liquid is
either colorless, or contains a coloring matter, which is usually red, but
sometimes yellow or green.

§157.

With the Nemertini, whose blood is red (1> but as yet imperfectly known,
the circulation appears to be due to two cardiac dilatations concealed in the
cephalic extremity.1 (2)

The Hirudinei have, beside the two median vessels, two lateral ones also,
which intercommunicate by very numerous transverse vessels.® From the
contractions of these vessels, the blood is driven sometimes forwards, and

1 For the blood-globules of the Annelides, see
fPagner, Zur vergleich. Physiol, d. Blutes, lift. I.
p. 23, lift. II. p. 39. According to him, those of
TerebeLla (Ibid. lift. I. fig. 8) are pale red, circu-
lar discs. Here the exception is remarkable, sup-
posing there was not an error of observation. It
appears that beside the blood which circulates in
the vessels the fluid contained in the visceral cav-
ity of the Chaetopodes plays also an important
part in the act of nutrition, for the eggs and the
spermatic particles which with these animals are
often detached from the ovaries and testicles at
a time when still quite imperfect, attain their com-
plete development while remaining in the visceral
cavity, probably by means of this nutritive fluid.
See Quatrefages , Ann. d. Sc. Nat. Y. 1846, p. 379.

1 According to Milne Edwards (Ann. d. Sc. Nat.
X. 1838, p. 197), the blood of the Nemertini is color-
less.

2 The vascular system of Polystemma has been
distinctly seen by Dugis (Ann. d. Sc. Nat. XXI.
1830, p. 75, PI. II. tig. 6), and by Orsted (Bes-
chreib. d. Plattwurmer, p. 17). It is composed of
many longitudinal vessels, which intercommunicate
not by transverse ones, but by arcuate anastomo-
ses at the cephalic extremity, and by two hearts in
the cervical region. According to Orsted , these

hearts are divided into two chambers, the anterior
having deep-colored blood, while that of the posterior
one is more clear. This arrangement has led this
naturalist to regard as hearts the bodies described
by Ratkkt. with Borlasia striata , as cerebral gan-
glia, and as blood-vessels, the nerves which are given
off from them laterally (see above, § 148, note 2)*
But if Quatrefages' figures of the nervous and
vascular systems of Nemertes mandi/la are exam-
ined (Regneanim. de Cuvier £d. illustr. Zoophytes.
PI. XXXIV. fig. 1), it will be seen that there are
here three main trunks, a median and two lateral.
These last accompany the lateral nerves, while a
bifurcating vessel which passes from the median to
the two lateral trunks, embraces closely, iu a loop-
like manner, the two cerebral ganglia, so that they
easily escape observation. This is perhaps true
also of Borlasia.

3 The sanguineous system of Sanguisuga has
been very carefully described by Brandt (Med.
Zool. II. p. 247, Taf. XXIX. B.) ; see also Boja-
nus , in the Isis, 1818, p. 2089, Taf. XX YI. fig. 3. 4.
With Nephelis , there are only two lateral vessels
and an abdominal one, lying along the ventral me-
dulla •, see Muller , in Meckel's Arch. 1828v p. 24v
Taf. I. fig. 1.

§ 157.

*

TIIE ANNELIDES.

1G9

sometimes backwards and oscillates from one side to the other, through the
transverse vessels.® With most genera, the blood is red, being colorless
with a few only, and it is always poor in corpuscles.® The Chaetopodcs
have no lateral vessels. Their circulation is often due to pulsatory organs,
and there is a great variety in the disposition of their vascular trunks and
sinuses.

With the Abranchiati, the dorsal vessel lies close upon the intestinal
canal, and is almost wholly enveloped in the hepatic tissue. At the ante-
rior extremity, it divides in many bifurcating branches, which, after encom-
passing the pharynx, unite below it, and form the ventral vessel.® This
vessel accompanies the ventral cord to the posterior extremity, and connects
with the dorsal vessel by bifurcating branches, as before. (7) The transverse
anastomoses connecting the dorsal and ventral vessel, form at each segment
simple, or torose canals.® With the small Lumbricini, these are usually

4 The irregularity of the blood-currents has, un-
doubtedly, given rise to the numerous different
opinions upon the circulation of these animals ; see
Dugis, Ann. d. Sc. Nat. XV. 1828, p. 30S ; Weber ,
in Meckel's Arch. 1828, p. 399 ; Muller , Ibid. p.
24 5 and in Burdach's Physiol. IV. 1832, p. 143 ;
and Wagner , Isis, 1832, p. 635. If the valves
which Leo ( Muller's Arch. 1825, p. 421, Taf. XI.
fig. 9) lias found in the dorsal and ventral vessels
of Piscicola , should be found also with other Hiru-
dinei, it would throw some light upon the real course
of the circulation.*

5 With Sanguisuga , Haemopis , Pontobdella ,
Nephelis , Piscicola , and others, the blood is red •,
it is colorless with some Clepsine , according to Fi-
lippi (Lettera sopral’Anat. e losviluppo delle Clep-
sine, 1839, Pavia, p. 11) ; it is also brown, violet or
red, according to the species. He also declares (loc.
cit. p. 8), that with Clepsine and Piscicola , which
live wholly upon the blood of the lower animals, the

* [§ 157, note 4.'1 The memoir of Gratiolet
(Mem. sur. ^Organisation du systdme vasculaire de
la Sangsue m^dicinale et de l’Aulostome vorace, pour
servir d Phistoire des mouvements du sang dans les
Hirudinees bdelliennes, in extract in the Comp.
Rend. 1850, XXXI. p. 699), is worthy of a special
reference in this connection. lie says : “ The lat-
eral vessels, whose walls are very muscular, are
the principal organs for the movement of the blood;
they contract alternately, as has been well observed
by Dugis, Weber Sind Muller , and their contained
blood moves in a circular manner, sometimes one
way, sometimes the opposite.

“ The branches given off by these lateral vessels
are of two kinds :

“ A. Those destined for the skin, and which are
ramified in the respiratory net-works ; they never
anastomose with those of the opposite side. Before
their final and minute ramifications, they form a
large varicose net-work under the skin, which hith
erto has been regarded as a plexus of hepatic ves-
sels, but which is positively an interlacement of
blood-vessels.

“ B. The other branches are destined for the
small intestine, and its spiral valve for the testicles,
the copulatory apparatus, to the loops and to the
muciparous vesicles.

<;AU these branches arise from the branches or the
large arches which form a free anastomosis between

15

vascular system communicates directly through
small canals with the coeca of the digestive canal,
so that the contents of this last may pass into the
blood without being changed.!

6 See Hen/e , in Muller's Arch. 1837, p. 83, Taf.
VI. fig. 5 ( Enchytraeus ), and Hojfmeister , De
vermibus quibusdam, &c-, loc. cit. p. 14, Taf. II. fig.
4 ( Saenuris variegata).

1 With Lumbricus , there are, beside the princi-
pal ventral vessel, three others smaller, and in di-
rect connection with the ventral cord. Two of these
pass off laterally, and the third underneath ; see
Leo, De Structura Lumbrici terrestris, p. 27 ; Dugis
Ann. d. Sc. Nat. XV. 1828, p. 298; and Morren,
loc. cit. p. 152, Tab. XXI.-XXIV. fig. 5, who
especially has carefully described the vascular sys-
tem of Lumbricus terrestris.

8 The transverse anastomoses are simple with
Lumbricus , but torose with Saenuris ; see Hojf-
meister , loc. cit.

the two lateral vessels. The consequences of this
form of structure may be easily summed up. The
blood oscillates from the alternate contractions
from one pulmonary net-work to another. It circu-
lates in the principal organ of the intestinal ab-
sorption, in the testicles, and in the muciparous
glands.

“ This circulation, very different from that which
Dugis admits in the alleged pulmonary vesicles,
shows how various are the means employed by na-
ture. Here she determines the course of the blood
by means of valves and stoppers ; while elsewhere
she accomplishes the same end by causing certain
blood-currents to prevail over others.”

The valvular structure of the vessels with Pisci-
cola , as mentioned by Z>o, has since been con-
firmed by Ley dig (loc. cit.), who has found it also
with Clepsine. Leydig calls the attention to
another kind of circulatory system in Piscicola ;
see loc. cit. p. 116. But this point has not yet been
well made out ; see also Mor/uin-Tandonr loc. cit.
p. 133, PI. X. fig. 10, 15, 16, and PI. XII, fig. 13.
-Ed.

! [ § 157, note 5.] The recent observations of
Leydig (loc. cit. p. 119), have shown the blood of
Piscicola to be always colorless. This view is proba-
bly the correct one, since it better accords with the
histological relations of the blood of these animals.
— Ed.

170

THE ANNELIDES.

§ 157.

only in the anterior segments of the body.® With the genus Lumbricus,
the cardiac organs consist of five to nine pairs of moniliform, transverse
canals, situated above the stomach, and whose pulsations are very dis-
tinct.(10) With all the Abranchiati yet examined, the blood is red.

With the Capitibranchiati, there are often two dorsal vessels, one imme-
diately subcutaneous, the other lying, as usual, on the intestine. al) This
duplicity of the dorsal vessel is observed particularly with those species
which have a coiled intestinal canal/13’ In this case, there is also a second
ventral vessel accompanying the coils of the intestine. All these longitudi-
nal vessels interanastomose very frequently, and send many transverse
branches to the intestine and the walls of the body, where they blend with, the
capillary system. Not unfrequently, the dorso-intestinal vessel is dilated
at its anterior extremity, above the pharynx, into a large, pulsatory, heart-
like canal, which sometimes has two lateral arcuate, sinuses situated at the
commencement of the intestine/13’ The extremity of this vessel sends off,
right and left, many branches to the branchiae, which are situated in this
region. Leaving these organs, these vessels are distributed, some in front
to the tentacles, and to the other organs surrounding the mouth ; while
others pass below to unite with the ventral vessel. As the blood is thrown
from behind forwards in the dorsal vessel, and thence passes into the bran-
chiae, this vessel may be called a dorsal vein, and its dilatation a branchial
heart ; while the ventral vessel, which receives the returning blood from the
branchiae, would be an abdominal aorta. But there are other reasons for
this view. The dorso-intestinal vessel, from its intimate connection with the
liver, might well serve the function of a Vena portarum, while the close
union of the ventral vessel to the ventral cord, is undoubtedly for the purpose
that the latter, as a central nervous mass, may receive arterialized blood di-
rectly from the branchiae. With these animals (the Capitibranchiati), the
blood is red in some, and green in others/14’

The Dorsibranchiati often have double dorsal and ventral vessels, two of
which belong to the intestinal canal, and two to the walls of the body/15’
With some, these longitudinal vessels are divided into two or three branch-
es/16’ The principal dorsal vessel is sometimes dilated at its anterior ex-
tremity, above the pharyngeal tube, into a cardiac sinus, to which, at the
beginning of the intestine, there are added two lateral, arcuate dilatations. a7>

0 Enchytraeus , Chaetogaster, and Nais. The
vascular system of Euaxes and Lum brie ulus is
very remarkable in this respect. Instead of trans-
verse anastomoses, there are, in each segment of the
body, two vessels which pass off from the dorsal
trunk, and divide into many coecal branches ; see
Treviranus , Beobacht. aus d. Zoot. loc. cit. p. 60 ;
and Grube , in Wiesmann's Arch. 1841, I. p. 205,
Taf. VII, tig. 1, 2, d.

10 See Dugts, loc. cit. PI. VIII. fig. 1, and Mor-
ren , loc. cit. p. 162, Tab. XX.-XXIIL, XXI.-
XXIV. fig. 1.

11 Milne Edwards has made very beautiful re-
searches upon the vascular system of the Capiti-
branchiati ; see Ann. d. Sc. Nat. X. 1838, p. 193,
PI. X. XI.

1 2 Ampfiitrite and Siplionostomum', see Rath-
kc. Danzig. Schrift. loc. cit. p. 76, 88, Taf. V. fig. 4,5.

13 With Terebella, there is a vascular heart and
two lateral sinuses} see Milne Edwards , loc. cit. PI.
X. XI. fig. 1. With Siplionostomum , there is a
similar cardiac dilatation upon the pharynx, and it
is divided into two chambers by a well-marked

constriction at its posterior part ; see Rathlci , loc.
cit. p. 89, Taf. VI. fig. 5, f. g.

14 With Terebella , Amphitrite , and Serpula ,
the blood is red ; with Siplionostomum , Chlorae-
ma , and some species of Sabella and Serpula., it is
green.

15 We are indebted to Milne Edwards for very
detailed accounts of the vascular systsm of the Dor-
sibranchiati ; see Ann. d. Sc. Nat. loc. cit. PI. XII.
XIII.; see also, for that of Arenicola , Stannius ,
in Muller's Arch. 1840, p. 357.

16 With Eunice sanguinea , there is a double
dorso-intestinal vessel ( Milne Edwards , loc. cit.
PI. XII. fig. 2, 3 1 ) ; and a double ventral one
with Nephtys Hombergi. With Arenicola , there
are three ventral vessels accompanying the ventral
cord (Muller, in Burdach's Phys. loc. cit. p. 147).
and with Amphinome, Grube has found three
dorsal ones beside, all widely separated from each
other.

17 Eunice ; see Milne Edwards , loc. cit. PI.
XII. fig. 2. The vascular system here resembles
that of Terebella.

$ 158.

THE ANNELIDES.

171

These last are sometimes found alone.08' With many of these An-
nelides, the transverse vessels are dilated, before branching, into real
branchial hearts.09' As their branchiae are variously situated among the
transverse anastomoses, the distinction between the arterial and venous
blood is not as marked as with the Capitibranchiati ; it must be arbitrary,
as with the Hirudinei and Abranchiati. The blood is usually red, but
sometimes is yellow or nearly colorless/20'

CHAPTER VII,

RESPIRATORY SYSTEM.

§ 158.

With the various families of the Annelides, the respiratory organs are
formed after wholly dissimilar types.

With the Nemertini, they are least developed, for, excepting two longitu-
dinal fossae upon the sides of the cephalic extremity,01 there are no organs
which can be regarded as of this nature.

These two respiratory cavities are of variable depth, and their lateral
borders are so approximated as to have the aspect of a longitudinal open-
ing, and with some they are situated so far out on the cephalic extremity as
to be blended together.® They are lined with a delicate ciliated epithe-
lium, quite different from that covering the rest of the body,® and by the
vortex actions of which, fresh water is brought constantly in connection
with the blood.® Considering the smallness of these organs, it is very
probable that the whole skin has also a respiratory function.

18 Arenicola ; see Milne Edwards, loc. cit. PI.
XIII.

19 Eunice ; Ibid. PI. XII. fig. 2.

20 With Eunice, Nephtys,Glycera , and Areni-
cola, the blood is red ; with Phyllodoce, it is yel-
low 5 and it is nearly'’' colorless with Aphrodite,
Polynoa, and Sigalion ; see Milne Edwards, loc.
cit. p. 196.*

1 See Muller, Zool. Danica. Tab. LXVIII. fig.
1-4 ( Tetrastemma ( Planar ia ) viride ) ; JJe/le
Chiaje, Memor. loc. cit. Tav. LXXVIII. fig. 8, a
( Polia genicu/ata); Quay anti Gaimard, Atlas
Zool. de P Astrolabe Zooph. PI. XXIV. fig. 10 ( Bor -
lasia viridis ) ; and the Diet. d. Sc. Nat. LVII. Art.
Ters, p. 574, PI. Parentomozoaires, Nemert£s, fig.
1, 2 ( Borlasia Angliae, and Cerebratulus hiline-
atus ) ; also Huschke , Isis, 1830, Taf. VII. fig. 1-3.
Notospermus drepanensis.

^ Tetrastemma vi/ide, Polia genicu/ata, and

Micrura fasciolata ( Ehrenberg , Symb. phys.
Phytozoa Tab. IV. fig. 4. e. i. g.).

3 See Quatref rges, lt£gne anim. illustr. Zooph.
PI. XXXIV. fig. 1, b. b. ( Nemertes Cainillae ).

4 Rathkc (see above, § 149, note 1) is of the opin-
ion that these two cephalic fossae are the seat of
touch -, but the view of Orsted (Beschreib. d. Platt-
wurmer, p. 18, 77), who thinks them of a respira-
tory nature, is, perhaps, the more correct. In sup-
port of this last, is the fact of the presence of cili-
ated epithelium, and of a very large blood-vessel
directly beneath them (see Quatref ages, loc. cit.
PI. XXXIV. fig. 1, g. g. {Nemertes Camillae ))
and which, in many Nemertini, is clearly seen
through the thin epithelium *, see Muller, Zool.
Dan. Tab. LXVIII. ( Tetrastemma vivire ) ; Belle
Chiaje, Memor. Tav. LXXVIII. fig. 8 ( Polia
geniculata ), and Isis, 1830, Taf. VII. ( Notosper-
mus drepanensis).

* [ § 157, note 20.] See also for the blood of the Annelides, Quatref ages, Ann. d. Sc. Nat. XIV.
1850, p. 287. — Ed.

172

THE ANNELIDES.

§ 159.

§ 159.

With the Hirudinei, and Lumbricini, the peculiar canals found in the
abdominal cavity may be regarded as internal branchiae, or as aquiferous
vessels.

The intimate structure of this aquiferous system is difficult to unravel
with the Hirudinei. It is most easily observed with the Branchiobdella ; here
there are only two pairs of curved canals whose inner surface is ciliated.
One of these pairs opens upon the ventral surface at the beginning of the sec-
ond third of the body, while the other opens at the extremity near the median
line. Each of these four canals is dilated just before its external opening
into a round, yellow cavity, from which pass off many loop-like vessels. (1)
With the other Hirudinei, these organs in pairs are more numerous, and
situated one after another from the second third to the extremity of the
body.

It is remarkable that the ciliated epithelium lining these canals with Bran-
aiiobdella, is absent in all the other species.®

The structure of the respiratory system of the Lumbricini is not less
difficult to be understood. With all the genera there are, at the commence-
ment and on each side of the intestine, very tortuous canals which open
upon the ventral surface, by a narrow orifice near the median line. These
canals are lined with long cilia which have an undulatory movement ; <3)
they also are colorless and sometimes have dilatations before opening exter-
nally, but they never contain air, so that the terms tracheae or pulmonary
cells, have been erroneously applied.® Often they float loosely in the
cavity of the body, and their free extremity has an orifice surrounded by
long vibratory cilia.® With some, however, they terminate by thickly-

1 See Henle, in Muller's Arch. 1835, p. 576,
Taf. XIV. fig. 1. This epithelium would undoubt-
edly favor the constant renewal of water in these
canals.

2 With Sanguisuga, there are seventeen pairs
of these organs. They have been taken by Brandt
(Med. Zool. II. p. 251, Taf. XXIX. A. fig. 55-58)
for organs of special secretion, since he has seen a
whitish liquid escape from their ventral orifices.
The riband-like organ of these Annelides is not,
moreover, as is usually supposed, a simple canal,
but is composed of numerous interwoven and fre-
quently interanastomosing canals, having no trace
of ciliated epithelium.

From Dugts' remark (Ann. d. Sc. Nat. XV.
1828, p. 303, PI. VIII. fig. 2), I think it probable
that this net-work is formed of blood-vessels which
are occasionally empty, for I have always found
them colorless.

In this case, the real aquiferous canals are prob-
ably concealed in the net-work, and from their want
of ciliated epithelium not easily seen.

With Nephelis vulgaris , I have seen the same
number of internal branchiae as with Sanguisuga.
Here, the aquiferous system appears as a knot of

* [§ 153, note 2.] See, upon the circulatory sys-
tem of Branchellion , Quatrefages (Ann. d. Sc.
Nat. XVIII. 1852, p. 314). According to him, the
general cavity of the body here, is represented by
a collection of canals which are lacunae. This
forms a vascular lymphatic system which circulates
chyle to the branchiae ; these last are, therefore,
li branchies lymphatiques.”

colorless, non-ciliated canals connecting with a
vesicular pouch which is filled with red blood 5 so
that in the posterior two-thirds of the body there
is a double row of seventeen sanguineous sinuses,
inside the lateral vessels. These sinuses, already
carefully described by Muller ( Meckel's Arch.
1828, Taf. I. fig. 1), take no part in the pulsations
of the main vessels, and are not alternately emp-
tied and filled during the transverse circulation of
these animals.

A very interesting fact to me, is the existence
with this Nephelis , of a multi-lobulate, rosetted,
ciliated, colorless organ in the interior of these
sanguineous sinuses.*

3 See Henle, in Muller's Arch. 1837, p. 84, Taf.
VI. fig. 7, 8, v. w (Enchytraeus) ; and Gruithvi-
sen , Nov. Act. Acad. Nat. Cur. XI. 1823, p. 238,
Tab. XXXV. fig. 1, i., XIV. 1828, Tab. XXV. fig.
5 ( Nais and Chaetogaster).

4 An aqueous respiratory fluid circulates in
these canals undoubtedly by the aid of cilia. The
terrestrial Lumbricini which live only in the damp
earth obtain this fluid therefrom.

•5 I have observed this with Saenuris varie-
gata, Luinbriculus variegatus , Nais elinguis ,

lie also states as conclusions :

1. The non-communication of the abdominal ves-
sels with the branchiae.

2. The existence of a subcutaneous lymphatic
vessel.

3. The origin from this vessel of trunks which
go to the branchiae. — Ed.

§ 160.

THE ANN ELIDES.

173

arranged loops.® With Lumbricus, these aquiferous canals are sur-
rounded by a very distinct vascular net-work, which has a botryoidal
aspect from its numerous pedunculated, vesicular dilatations which are filled
with blood.®

§ 160.

With most of the Capitibranchiati, and Dorsibranchiati, the respiratory
organs consist of external branchiae, which are very apparent, although
having variations in their development. They always consist of lobules or
filaments covered with ciliated epithelium, and in which are very con-
siderable vessels as branchial arteries and veins. (1) The branchiae are
here always situated between the venous and arterial systems, so that a
portion only of the whole blood is made to pass through the respiratory
organs.

It is possible that the two bundles of tentacles which are found with
many Capitibranchiati, as infundibuliform,® or spiral® tufts, arc also res-
piratory ; for their vibratory organs not only draw in food, but also pro-
duce a constant change of the water.

Other Capitibranchiati have distinct and exclusively respiratory organs
in the cervical region, which are either dendritic,® or semi-pinnate.®

With the Dorsibranchiati, nearly every segment of the body has branchiae
upon both sides of its dorsal surface. These are so simple and rudiment-
ary with the Ariceae, and Nereideae, that they consist only of simple lob-
ules, exactly resembling the cirri of the feet.®

Enchytraeus albidus , and others. Those canals
thus situated remind one of the trembling organs
of Rotatoria, connecting the two lateral canals
with the cavity of the body 5 see above, § 138.

6 With Lumbricus terrestris , and its allie<J
species, I have as yet been unable to find any ori-
fices of the aquiferous canals. He rile also ( Mul-
ler's Arch. 1835, p. 580) has always found them
looped upon themselves. They may however exist,
although they have eluded the notice of Henle and
myself, for the respiratory organs of Lumbricus
are so difficult to study that there is yet no de-
scription or figure giving any idea of their com-
plexity 5 see the poor figures of Lumbricus ter-
restris by Leo (loc. cit. p. 25, Tab. I. fig. 4), and
Morren (loc. cit. p. 53, 148, Tab. XIV. XV.).
Those of Hoffmcister , although more detailed, are
scarcely less unsatisfactory (loc. cit. p. 15, Tab. I.
fig. 35, 36). It now remains to inquire as to the
relations existing between these aquiferous canals
and the glands at their base which have been
taken by many for mucous pouches. I cannot, for
my own part, perceive that these glands with the
Lumbricus terrestris , excrete any liquid what-
ever upon the ventral surface. On the other hand,
I have often seen escape from the back of this
animal, a watery liquid which was only the con-
tents of the cavity of the body, issuing through
small orifices upon each side of the median line
between the segments of the body. Although I do
not know, yet I suppose, that similar orifices exist
with the other Lumbricini, and thus, by these ori-
fices and by those of the internal branchiae, the
necessary renewal of water for these last, can take
place. This hypothesis appears admissible since
the cilia of the aquiferous canals always move in
the same way.

*l§ 159, note 7.] See, for many details on
these parts, Gegenbaur (Ueber d. sogenannten

15*

7 These vesicular dilatations do not pulsate, and
are undoubtedly analogues of the simple sinuses
which communicate with the aquiferous canals of
Nephelis vulgaris.*

1 These respiratory organs may be taken as
analogous to the aquiferous vessels of the Lumbri-
cini, which can be everted so that the internal cil-
iated surface becomes external, and the external
blood-vessels internal.

2 Serpula , and Pro tula.

3 Sahella.

4 Terebella ; see Delle Chiaje , Mem. loc. cit.
Tav. XLIII. fig. 1-5, Tav. XLV. fig. 2, 10 ; and
Milne Edwards , Ann. d. Sc. Nat. X. 1838, p. 200,
PI. X. XI. fig. 1. There are here on each side of
the neck three multiramose, contractile branchiae
which are placed close together. Into these a
large portion of the blood of the median dorsal ves-
sel enters by six lateral branches, while the re-
maining portion passes on through the dorsal ves-
sel to the tentacles and the borders of the lips.

In each branchial tuft there are a simple artery
and a vein placed side by side, which anastomose
at its extremity in an arcuate manner.

The returning blood from the six branchiae
passes by as many veins into the median dorsal
vessel, and the frequent strong contractions and
dilatations of the branchiae, certainly very much
aid the current.

5 Amphitrite ; see Pallas , Miscell. zool. p. 120,
Tab. IX. fig. 1, 5, 0, 8, e, e ; Rathkt , Danzig.
Schrift. loc. cit. p. 59, Taf. V. fig. 1, 3. Here the
four semi-pinnate branchiae are upon both sides of
the second and third rings of the body, and each
lamella contains a tightly-closed vascular net-
work.

6 The filaments of these branchiae are very short

Respirationsorgane d. Regenwurms, in Siebold
and Kblliker's Zeitsch. IV. p. 221). — Ed.

174

THE ANNELIDES.

§160.

It is remarkable that the branchiae are perhaps entirely wanting, with
the Aphroditae,<7, while they ate often highly developed, partly in a
pectinate and partly in a fasciculate manner, with the Euniceae, Amphino-
mae, and Arenicolae.®

with Glycera, Nereis , Lycastis , Nephtys , and
others ; but with Cirratulus , they are very long.
With Phyllodoce , and Alciopa , there are flat-
tened lobules. But with Lumbrinereis, Aglaura ,
and some other allied genera, these are wholly
wanting ; see Milne Edwards , Classif. loc. cit.
The question here arises if the Dorsibranchiati
which have atrophied branchiae, have not there-
fore internal respiratory organs. It is at least
probable that the two pairs of remarkable net-
works surrounding the pharynx of Nereis and
which have given rise to various interpretations
(see Rathk.i, Be Bopyro et Nere'ide, p. 48, Tab. II.
lig. 5, bb, tig. 8, f, g, h, and Tab. III. tig. 14 ;
also Milne Edwards, Ann. d. Sc. Nat. X. 1838,
p. 210, PI. XII. fig. l,o, p) are properly internal
branchiae. They receive the blood from the dorsal
vessel through two lateral vessels, and it is returned
to the median ventral vessel by two others which
are also lateral. Moreover, according to Rathkt !
(loc. cit. p. 40), there is, between every two feet
upon both sides of the segments of the body, a small
orifice opening into the cavity of the body and
through which water for respiration can pass.

1 Different observers have equally different
opinions upon the branchiae of these animals. For
my own part, I have found no trace of these
organs, either internal or external with Aphrodite
aculeata , and hystrix. I suppose, therefore, that
water enters the cavity of the body by orifices
which are very small and difficult to be seen, and
comes in contact with the entire vascular system.

Milne Edwards (Regne anim. illustr. Ann6-
lkles, PI. XVIII. fig. 2-1, c) has figured rudiment-
ary branchial lobules with Aphrodite acnlatea ,
which are crenulated and concealed between the
scales, and are, perhaps, invisible, when the animal
is in a fresh state. Moreover, Sharpe y (Cyclop.
Anat. and Phys. I. p. 618), having observed with
the same species a very active ciliary motion espe-
cially upon the external surface of the intestine
and its coeca, it is very probable that here, as with

* [ § 160, note 8.] The respiratory organs of the
Annelides have been much studied by Quatrefa-
ges (Ann. d. Sc. Nat. XIV. 1850, p. 290), and the
following is his resume :

“1. The respiration is at first general and en-
tirely cutaneous ( Lumbrinereis , Lysidice, He-
sione, &c).

“ 2. It is still cutaneous, but is confined or concen-
trated upon particular rings of the body {Chae-
topterus).

“ 3. It is localized upon certain points of each
ling, without the structure of these points being
sensibly modified {Nereis).

“ 4. The first degree of the specialization of the
respiratory organ appears under the form of a sim-
ple cul-de-sac, or an ampulla into which the blood
flows {Glycera).

“6. The branchiae become gradually character-

the Astero'idae, the respiration occurs by water
entering the cavity of the body and bathing the
intestine.

8 With On up his , and Eunice , the branchiae
are pectinate or semi-pinnate •, see Milne Ed-
wards, Classific. loc. cit. With Diopatra, and
Chlotia, each branchia consists of a single ramified
fasciculus ; but with the Amphinomae, and Areni-
colae, there are several fasciculi 5 see Milne Ed-
wards, loc. cit. and his plates annexed to Regne
anim. de Cuvier, Annelides j also Stannius, Isis,
1831, Taf. VI. With Eunice, the blood of the
median dorsal vessel passes first into the inferior
lateral vessels which have the form of cardiac
sinuses, and by the pulsations of which it passes
into the branchial vessels, whence it returns into
the other two dorsal vessels by the superior lat-
eral ones ; see Milne Edwards, Ann. d. Sc. Nat.
X. 1838, p. 207, PI. XII. fig. 2.

With Amphinome , there is at the base of each
branchial fasciculus, in the cavity of the body, a
Plexus branchialis, closely resembling the won-
derful net-works of Nereis , and from which the
blood passes into two lateral vessels which here
exist •, see Catal. of the Physiol. Ser. &c. II. PI.
XIV. fig. 10, or Rymer Jones, Outlines, &c., p.
218, fig. 93.

With Arenicola piscatorum, only the thirteen
middle segments of the body have branchial fas-
ciculi. These communicate with the ventral and
dorsal vessels by simple lateral vessels.

As there exist here at the extremity of the body
between the two dorsal and ventral vessels, two
cardiac sinuses, it is probable that these force the
blood from before backward into the ventral vessel,
and thence by the lateral vessels into the branchiae j
90 that these inferior lateral vessels would be
balled arteries, and the superior lateral vessels
which return the blood to the dorsal vessel, veins j
see Milne Edwards, Ann. d. Sc. Nat. loc. cit. p.
215, PI. XIII.*

ized by the formation of a canal which communicates
with the more or less spacious lacunae.

“ 6. These true branchiae may be distributed all
along the body {Eunice sanguinea).

“ 7. They may be concentrated upon a certain
number of rings situated near the middle of the body
{Eunice Bellii , Arenicola, Uerrnella, Polydora).

“ 8. They may be concentrated towards the ante-
rior extremity of the animal, and occupy only a few
rings ( Terebella , Pcctenaria).

u 9. Finally, they may be located wholly at the
extremity of the body, and form only a double tuft
(Sabella, Serpula).

“ 10. In considering sometimes the entire body,
sometimes each ring separately, a real distinction
between the venous and the arterial system may
nearly always be made out.”- Ed.

§§161, 162.

THE ANNELIDES.

175

CHAPTEll VIII.

ORGANS OF SECRETION.

§ 161.

Many Annelides are covered with a mucus which is secreted by small,
simple follicles situated in the skin.'1'

The calcareous tubes of the Serpulini, appear to be secreted by a collar
surrounding the first segment of the body.® It is not yet decided that
the leathery tube in which many other Branchiati are concealed,® is
secreted by an analogous organ.

Those Oapitibranchiati which form tubes with grains of sand, bits of
shells, &c., have, perhaps all, an opening close behind the mouth upon the
ventral surface. This opening is in connection with many glands situated
at the anterior extremity of the body, which probably secrete a substance
for the gluing together of the materials of these tubes.®

CHAPTER IX.

ORGANS OF GENERATION.

§162.

The Annelides reproduce partly by
by a sexual apparatus.

l Similar muciparous follicles are arranged in
curved rows with the Hirudinei, upon both the ven-
tral and dorsal surfaces, giving the skin a granu-
lated aspect 5 see Brandt , Med. Zool. II. p. 244. I
have seen similar groups of follicles with the larger
Lumbricini.*

v The secretion of the calcareous matter occurs
here probably as upon the border of the mantle of
Mollusks.

3 Sabella , Onuphis , and Ckaetoptcrus.

4 As secreting organs of this glue, Rathkd has
correctly described four yellowish glands situated,

* [ § 161, note 1.] Ley dig ( Siebold and Kblli-
icer's Zeitsch. 1849, p. 109) has described with Pis -
cicola , Clepsine , Nephelis , and other Hirudinei,
cutaneous glands. These consist of an infundibu-
liform sac, which, exactly resembles a nucleated
cell, from which passes off a long, tortuous duct.

a transverse nssuration, and partly

with Amphitrite , upon the ventral surface of the
first and second segment of the body, and
opening by a common canal at the first seg-
ment •, see Danzig. Schrift. loc. cit. p. 71, Taf. V.
fig. 6, aa. fig. 2, d. With Terebella , and Sa-
bella , the two glands near the cephalic extremity,
are perhaps of the same nature. Grube , however,
thinks them male genital organs ; see, Zur Anat. d.
Kiemenwiirmer, ]>. 31, Taf. II. fig. 12, y.5 and
Milne Edwards , Ann. d. Sc. Nat. X. 1838, PI. X.
n. PI. XI. fig. 1, h. fig. 2, f.

With Piscicola , these are situated in the cephalic
and pedal shield, but in Clepsine, and Nephelis ,
they are also present in the skin throughout $ see
loc. cit. Taf. VIII. fig. 23. This structure is re-
markable from its resemblance to some of the cuta-
neous glands of the liigher animals. — Ed.

176

TI1E ANNELIDES.

$ 163.

Spontaneous transverse fissuration occurs particularly with the Abran-
chiati,'1* but has also been observed with the Nemertini,® and Branchiati.®
It occurs usually at the middle portion or at the border between the
second and third segments of the body. Very often there may be per-
ceived at this point, when this process has somewhat advanced, the place
where, with the two future individuals, there will be a new fissuration. If
the animal has a proboscis, tentacles, or eyes, these organs are developed
with the posterior individual before its final separation.®

These animals have no trace of genital organs, while this process of divi-
sion lasts. The individuals thus produced, re-divide, and this division
continues until a certain time of the year. It then ceases, and genital
organs being developed, reproduction takes place by eggs.

The extreme vulnerability and reproductive power of many Chaetopo-
des, give rise to their frequent multiplication by artificial and accidental
division. The fragments thus produced are finally developed, and the mu-
tilated animal ultimately regains its lost parts.® Some have the power of
voluntary division from the least handling of their body,® and these sep-
arated parts are probably developed to new individuals.

§ 163.

Most of the Annelides reproduce by sexual organs, and the few Lumbri-
cini which, as just observed, multiply by fissuration, have probably, like their
allied species, genital organs at certain seasons of the year.11’

The eggs of the Annelides present nothing remarkable ; they are always
spherical, and have a chorion and thin vitelline membrane containing a
finely-granular vitellus with a germinative vesicle and dot.® This

1 Lumbriculus , Na'is , Chaetogaster and Aeolo-
soma.

2 See Johnston , in the Mag. of Zool. and Bot. I.
1837, p. 534.

3 With the Nere'ideae.

4 Fissuration with many species of Na'is , has
already been noticed by O. F. Muller (Naturgesch.
einiger Wurm-Arten des siissen und salzigen Was-
sers. Taf. II. &c.). For that of Na'is proboscidea
and Chaetogaster diaphanus , see Gruithuisen ,
Nov. Act. Acad. Nat. Cur. XI. p. 243, Tab. XXXV.
fig. 1, 3 *, XIV. p. 412, Tab. XXV. fig. 2. For that
of Aeo/osoma , see Orsted in Kr dyer's Naturhist.
Tidskrift. IV. PI. III. fig. 7 ; and for that of Ne-
reis prolifera , see Miiller , Zool. Dan. II. p. 16,
Tab. LII. fig. 6. This last species is a very young
Nereis. It is probable that many other Branchi-
ati multiply in the same way. Quat ref ages ( Fro -
ricp's neue Not. No. 726,1845, p. 344) has recently
recognised a Syllis in Nereis prolifera.

Sars (Faun. litt. &c. p. 87, Taf. X. fig. 18, 19)
has observed multiplication by transverse division
with Filograna implexa , a young animal detach-
ing itself from the caudal end of this Serpula. I have
observed a like division with a Protula , a genus
allied to Serpula. According to Milne Edwards
(Ann. d. Sc. Nat. III. 1845, p. 180, PI. XI.) a sin-

* [§162, note 4.] See in this connection, Schultze
(Ueber die Fortpflanzung durch Theilung bei Na'is
proboscidea, in Wiegmann's Arch. 1850, p. 293).
He has carefully described this form of multiplica-
tion with tills animal, and according to him it is a
true fissuration , and not a gemmation , as that of
Syllis, described by Frey and Leuckart. See fur-

gle individual of Myrianida fasciata, which is al-
lied to Phyllodoce, produces six young by as many
successively disposed divisions. According to Frey
and Leuckart (Bcitr. &c. p. 94, Taf. II. fig. 1),
there are with Syllis prolifera also, several young
developed simultaneously, one after the other, at
the caudal extremity.*

5 See the experiments upon this subject with the
Lumbricini by Reaumur , Bonnet , Trembley , and
Roesel. Daly ell (Froriep's neue Not. No. 331,
18-10, p. 1) has observed a similar mode of repro-
duction with Sabella.

6 This has been observed by Grube , with Polia
delineata (Zur Anat. d. Kiememv firmer, p. 58).
Meckclia annul ata has also the same property.

1 Aeolosoma.

2 See Wagner , Prod. Ilist. gener. loc. cit. Tab. I.
fig. 9, 10 (Sanguisuga and Nephelis) ; S tannius,
in Muller's Arch. 1840, Taf. II. fig. 1, 2 ( Areni -
cola piscatorum ) ; Milne Edwards , Ann. d. Sc.
Nat. Ill, 1845, PI. V. fig. 2, 3, PI. IX. fig. 43, 44
( Terebella and Protula ); and Sars , in Wieg-
mann's Arch. 1845, I. Taf. I. fig. 13 (Polynot cir-
rata). If the bodies which H. Meckel has figured
(Muller's Arch. 1844, p. 481, Taf. XIII, fig. 13-
23) as the eggs of Lumbricus terrestris , are really
such, which I think is doubtful, they differ much

ther Leuckart , Ueber die ungeschlechtlichte Ver-
mehrung bei Na'is proboscidea, in Wiegmann's
Arch. 1851, p. 134, Taf. II. fig. I.-III. ; and Krohn,
Ueber die Erscheinungen bei der Fortpflanzung von
Syllis prolifera und Autolytus prolifer. Ibid. 1852,
p. 66. — Ed.

$ 164.

THE ANNELIDES.

177

vitellus is usually whitish or yellowish, but rarely of a more marked
color.®

With the Hirudin ei and Lumbricini, the spermatic particles are filamen-
toid and very active, while with the other Annelides they have the form of
Cercariae. m

§ 164.

With the Hirudinei, and Lumbricini, the two sexes are always united in
the same individual. The sexual organs consist of testicles, vasa deferen-
tia, and vesiculae seminales ; then, ovaries, oviducts, and the male and
female copulatory organs. The female copulatory organs are upon the
ventral surface of the anterior part of the body and behind the male
organs — so that two individuals by placing together their anterior ventral
surfaces in an inverse position, can be mutually impregnated. (1)

The excretory ducts of both sexes are often lined with a very delicate
ciliated epithelium.

from the eggs of other Annelides, in containing be-
tween the vitellus and vitelline membrane a layer
of caudate cells. These cells, of variable number
and size, but always of uniform size in the same
egg, have often been compared, from their form, to
Naviculacae 5 see Henle , in Muller's Arch. 1835,
p. 591, note, and Hojfmeister , De vermibus qui-
busdam, &c., Tab. II. fig. 14-17.

3 The vitellus is rose-colored, or greenish, with
Clepsine , and violet with Polynoc.

■l The development of the spermatic particles of
the Hirudinei and Lumbricini is very remarkable.
The cell-membrane of the parent cells, in which the
spermatic particles are usually developed, disap-
pears before these last are developed. There are then
small cells grouped around a discoid nucleus. These
cells lengthen out, and finally become spermatic
particles, and they remain attached to the disc until
fully developed. If a bundle of these is placed
in water, they separate and become intertwisted in
the usual manner 5 see Henle, in Muller's Arch.
1835, p. 584, Taf. XIV. fig. 4, 6, 7, 9 j Kolliker ,
Beitr. zur Kenntn. d. Geschlechtsverh&ltnisse, p.
17, Taf. II. fig. 16, 18, 19 $ H. Meckel , Muller's
Arch. 1844, p. 477, Taf. XIII. fig. 2-10 ( Sangui -
suga , Pontobdella , and Branchiobdella ) ,• and
Hojfmeister , De vermibus quibusdam, &c., Tab.
II. fig. 6-10. From Stannius ’ description and fig-
ures of the sperm of Arenicola ( Muller's Arch.
1840, p. 375, Taf. XI. fig. 3-6)*, • and Rathki of that
of Amphitrite auric oma (Danzig. Schrift. loc. cit.
p. 67, Taf. V. fig. 13) 5 and Quatrefages , of that
of Nemertes mandilla (RAgne anim. illustr. Zooph.
PI. XXXIV. fig. 3-5), we can conclude that the
spermatic particles of the other Annelides are de-

* { § 163, note 4.] For the spermatic particles
of the Hermella , see Quatrefages (Ann. d. Sc.
Nat. X. 1848, p. 167) 5 he describes them as being of
a cercaria-form. My own results on the spermatic
particles of the Annelides and their development,
do not agree with the view above expressed. Here,
as elsewhere, I have found them to be the metamor-
phosed nucleus of the daughter-cells. It is true
that with the Lumbricini they present some pecu-
liarities, but these are apparent only. The mul-
berry-like mass to which they are here found ad-
herent, is composed of the remains of the develop-
ment, and the spermatic particles which seem to ra-
diate from it in all directions present this appear-

veloped like those of the Hirudinei and Lumbricini.
While in the excretory* ducts of the sperm, the
spermatic particles are found in bundles •, and when,
as at the procreative period, many of these bundles
are collected together, their very active, undula-
tory movements give a most wonderful appearance
beneath the microscope ; see Morren , loc. cit. p.
178, Tab. XXIV.-XXVIII., and myself in Muller's
Arch. 1836, p. 42. Among the filamentoid sperm-
. atic particles of Hirudinei, those of Branchiob-
della are worthy of special mention. One of their
extremities is delicate and spirally turned (see my
observations, Muller's Arch. 1836, p. 42, Taf. II.
fig. 8), and terminates, according to Kolliker , by a
small vesicle (loc. cit. p. 18, Taf. II. fig. 16, f.).
With the Branchiati, the cercarian-form predomi-
nates, according to Quatrefages (Comp. Ilend.
XVII. 1843, p. 424). With the Nemertini, they are
either simply filamentoid ( Notospermus , accord-
ing to Orsted, Entwurf. einer Einth. d. Plattwiirm.
loc. cit. Taf. III. fig. 54) or more cercarian-form
( Nemertes , according to Quatrefages , Regne
anim. illustr. Zoojdi. PI. XXXIV. fig. 6 5 and Kol-
liker ^ Verhandl. d. schweiz. naturf. Gesellsch. bei
ihrer Versammlung zu Chur. 1844, p. 91).

For the spermatic particles of the Annelides, see
especially Kolliker in the Neue schweiz. Denkschr.
VIII. p. 33.*

» See Bojanus , Isis, 1818, Taf. XXVI. fig. 1 :
Brandt , Med. Zool. II. Taf. XXX. fig. 25 ( Sangm -
suga m&dicinalis) ; Leo , Muller's Arch. 1835,
Taf. XI. fig. 3 ( Piscicola geometrai) ; Morren ,
loc. cit. Tab. XXVII.-XXXI.; and Hojfmeister ,
De vermibus quibusdam, &c., Tab. I. fig. 29, 30
(Lumbricus and Enchytraeus).]

ance because they are then just escaping from the
daughter-cells, and the more or less adherence of
the membrane of these last to the particles, gives
the appearances above mentioned in the note. I
have observed the same appearances with some of
the Coleopterous insects, where the development
occurs unmistakably in special cells. These par-
ticles are, according to my own observation, hair-
like with the Hirudinei, and Lumbricini, but are
pin-shaped with some of the Capitibranchiati. — Ed.

t [ § 164, note 1.] See also Ley dig, Siebol eland
Kolliker' s Zeitsch. III. lift. 3, p. 318, and Quatre-
fages, Ann. d. Sc. Nat. XVIII. 1852, p. 299
(Branchellion). — Ed.

178

TIIE ANNELIDES.

$§ 165, 166.

With the Nemertini, and Branchiati, the sexes are upon separate individ-
uals, and the genital organs are composed simply of testicles and ovaries.

§ 165.

The structure of the genital organs of the Nemertini is yet quite obscure.
The few researches hitherto made only furnish the general result that the
sexes are separate.

There are numerous glandular follicles situated laterally in the paren-
chyma of the body between the skin and the intestinal canal, which are
closely aggregated and serially arranged.

With some individuals, these follicles contain eggs, and with others,
sperm. They ought, therefore, to be regarded as ovaries and testicles.
Each follicle opens separately upon the surface of the body.(1) 2 There are
very contradictory statements as to whether these animals have, or have
not, copul atory organs.

According to some Naturalists, the worm-like organ, concealed in a canal
extending along tire back, and which, with both sexes, is often protruded
and moved actively about, ought to be regarded as an excitatory organ, —
although no connection between it and the testicles or ovaries, has as yet
been found. According to others, it is a proboscis unconnected with the
genital organs.®

§166.

The disposition of the genital organs of the Hirudinei and Lumbricini,
is essentially different.

The first have only two simple genital openings, — one male, the other
female, both situated, one after the other, upon the median line of the ven-

1 See Dupes, Aim. d. Sc. Nat. XXI. 1830, p. 76,
PI. II. fig. 5 ( Polystemma ( Prostomum ) arma-
tum ) ; Johnston, Mag. of Zool. I. p. 532, PI. XVII.
fig. 2'*, 6*% Pi. XVIII. fig. 3* {Nemertes and
liorlasia) ; Orsted , Entwurf. einer Beschreib. d.
Plattwiinn. p. 22, Taf. III. fig. 41 ( Tetrastemma
varicolor ) -y Kolliker, Verhandl. d. Schweiz, na-
lurf. Versamml. zu Chur. p. 91 {Nemertes)-, and
Rathkd, Danzig. Schrift. loc. cit. p. 98 ( Borlasia
striata). This last author lias not seen the orifices
of the genital organs. Quatrefages (R££ne anim.
illustr. loc. cit. PI. XXXIV. fig. 1, n. n.) did not
see them with Nemertes Camilla, and Johnston
is also silent on this subject. According to Orsted
(Entwurf. kc. loc. cit. p. 25, Taf. III. fig. 47, of
Notospermus Jlaccidus) the Nemertini secrete
from the whole surface of their body, a gelatinous
mucus, which surrounds the eggs, and thus forms
an envelope into which they can draw their bodies.
Something similar to this occurs with the Lumbri-
cini and Ilirudinei. See below.

2 The Nemertini being of distinct sexes, this or-
gan can be regarded neither as a penis, nor as an
everted spermatic vessel, as Huschke has done
(Isis, 1830, p. 682, Taf. \ II. fig. 5). More prop-
erly could it be considered, with Orsted (Entwurf.
kc. p. 25), as an excitatory organ-, although RathlU
(Danzig. Schrift. loc. cit. p. 100, and Nov. Act. Acad.
Nat. Cur. XX. p. 233) regards it as of a tactile,
and Kolliker of a prehensile nature (Verhandl. d.
schweiz. p. 90). Other observers agree with
Ehrenberg (Symb. phys. loc. cit.) that it is an in-
testine and an everted oesophagus, its orifice being
a mouth ; but this is undoubtedly erroneous. With

Poti/slcmma armatum {Dupes, Ann. d. Sc. Nat.
loc. cit. p. 75, PI. H. fig. 5) Tetrastemma vari-
coior {Orsted, Entwurf. &c. p. 23, Taf. III. fig.
41), and Nemertes {Johnston, Mag. of Zool. I. p.
530, fig. 2 Quatrefages, Iiegne anim. illustr. loc.
cit. PI. XXXIV. fig. 2, and Kolliker , Verhandl. d.
schweiz. kc.) there is at the centre of this organ a
dart pointing forward*, which is homy, accord-
ing to Dupes, and calcareous, according to Orsted.
On each side of this dart, there is a reservoir of
many others, smaller and yet imperfect, destined,
probably, to replace the former when lost. Dupes.
Johnston, and Quatrefages, who regard this or-
gan as an intestinal canal, and Kolliker, who con-
siders it prehensile, all regard these darts as a kind
of teeth 5 but Orsted thinks they serve to excite
the genital organs. For my part, they involunta-
rily remind me of the darts of the Helicina.

[Additional Note.] — I have now satisfied myself
upon living individuals of Tetrastemma, that the
eggs can escape from the visceral cavity through
numerous lateral openings in the wall of the body.
I am also satisfied that with the Nemertini, the
walls of the digestive canal (the middle body-cavity
according to Quatrefages) are not the points of
departure of the genital organs, as Quatrefages
thinks, and who also would regard as a digestive
tube the snout of these animals, an organ which is
yet enigmatical. The very detailed figures which
this naturalist has given (loc. cit.) of the walls of
the digestive canal of these animals, present nothing
like an ovary, and show no trace of the presence
of germs.

P 166.

THE ANNELIDES.

179

tral surface. The posterior opening connects with a short muscular canal
which may be regarded as a reservoir of eggs.

From the base of this reservoir, a narrow spiral canal passes off, and
bifurcating into two oviducts, terminates with two round ovaries. (1) 2

From the anterior opening, a long filiform penis may be protruded,
which, when not erected, lies spirally concealed in a bulbous muscular
sheath. A. Ductus ejaculatorius extending from the seminal vesicles, opens
into each side of this sheath. These seminal vesicles are formed each by a kind
of continuation of the vas deferens into a varicose tortuous canal, which lies
in the midst of a dense cellular tissue. The Vasa deferentia are narrow,
and passing backwards along the sides of the body, receive upon their
internal surface the short excretory ducts of the five, nine, or twelve pairs
of round isolated testicles, which form a double row near the ventral
cord.®

With many Hirudinei, a portion of the skin is connected with the sexual
function. Such is the case with Nepkelis, with which numerous cutaneous
glands are developed upon the back and belly near the female genital
opening. The skin soon has a bloated, transparent appearance, so that the
animal appears to have a girdle about its anterior extremity. Before the
deposition of the eggs, these glands secrete a substance which hardens in
water, and surrounds the body of the animal like a horny belt. ' This belt
is filled with a greater or less quantity of eggs ; the animal then withdraws,
or slips out from it, while its two extremities are closed up by its own
elasticity; but the embryos developed in this egg-capsule are not thereby
prevented from making their escape.®

The Sangaisugae form cocoons in a similar manner ; but they are sur-
rounded with a very thick, spongy substance.® The various species of
Clepsine form sac-like capsules for their eggs, and which they usually carry
about with them, attached under their belly, — shielding them with their
body at the approach of danger.®

1 See Brandt, Mediz. Zool.II.p. 252, Taf. XXIX.

A. fig. 45, 46 ; Moquin-T andon, Monogr. loc.
cit. p. 80, PI. I .-III.; Leo , Muller's Arch. 1835,
p. 424, Taf. XI. fig. 10 ( Sanguisuga , Aulacosto-
inum , Nephelis, Pontobdella, and Piscicola.

According to the careful researches of Filippi
(Lettera sopra l’anat. e lo sviluppo delle Clepsine,
p. 16. Tav. I. fig. 5), Grube (Untersuch. iib. d. Ent-
wickl. d. Clepsinen. p. 6, Taf. III. fig. 3), and Fr.

Muller (. Muller's Arch. 1846, p. 138, Taf. VIII.),
the two ovaries of Clepsine and Nephelis , consist
of long flexuous cords surrounded by two more or
less long muscular sheaths, which are uninterrupt-
edly continuous into the oviducts ; they receive the
eggs as they are detached from the ovaries, and pass
them along by peristaltic movements.

2 Sanguisuga has nine pairs of testicles ( Brandt
Med. Zool. II. p. 252, Taf. XXIX. A. fig. 32-44).

The Vasa deferentia of the seven pairs with Pis-
cicola are dilated before reaching the two seminal
vesicles into two long and very flexuous tubes ( Epi-
didymis., according to Leo , loc. cit. 1835, p. 423,

Taf. XI. fig. 10). With Pontobdella , there arc

five pairs of these organs ; with Haemopis, eight ;
and with Aulacostomum , twelve ( Moquiu-T an -
don , Monogr. loc. cit. PI. III. fig. 8 ; PI. I. fig. 3,
PI. II. fig. 10). With Nephelis , the arrangement
is different, there being on each side of the poste-
rior part of the body, numerous testicular vesicles
united in a botryoidal manner ; see Moquin-Tan-
don , Monogr. loc. cit. PI. III. fig. 4.*

3 See Raycr , Ann. d. Sc. Nat. IV. 1824, PI. X.
fig. 1-6, and Moquin-T andon, loc. cit. PI. VI. fig.
4, e-h. These cocoons are often found as brown
scales, glued to aquatic plants. Piscicola forms
similar cocoons, but they never have more than one
egg each ; see Leo , loc. cit. p. 425, Taf. XI. fig. 6 ;
and Brightwell , Ann. of Nat. Hist. IX. 1842, p.
ll.t

4 See Rayer , loc. cit. PI. X. fig. 10, and Moquin-
T andon , loc. cit. PI. V. According to Wedeke
(Froriep's neue Not. No. 452, 1842, p. 183). the
medicinal leech ejects from the mouth as a scum,
the spongy envelope of these cocoons.

5 See Grube , Untersuch. fiber die Entwick. d.
Clepsinen, 1844, p. 1.

* [§> 166, note 2.] For many valuable details on
the genitalia of the Hirudinei, see the often-quoted
and valuable works of Leydig , loc. cit. p. 120. It
contains histological, as well as anatomical results.
According to him, Piscicola has six, and not seven
{Leo) pairs of testicles. — Ed.

t [ § 166, note 3.] See, for an histological exami-
nation of these genital glands in Piscicola , Ley-
dig, loc. cit. p. 122, Taf. IX. fig. 43, e. 49, a. b. c.
— Ed.

180

THE ANNELIDES.

§ 167.

§ 167.

The genital organs of the Lumbricini are very difficult of dissection ;
for often those of both sexes are intimately united together into a common
mass. It is certain, however, that the male and female orifices are always
in pairs and situated at the anterior extremity of the body, ne»r the ven-
tral median line.(1>

These orifices communicate with more or less numerous glands, sacs, and
pyriform or cylindrical vesicles.

Their nature as testicles, ovaries or sperm-receptacles, is known only by
their contents. As yet it has been possible to trace only very imperfectly
their excretory ducts. With some, two of these caecal organs have been
observed intersuscepted in each other. The internal one contained sperm-
atic particles, and should therefore be regarded as a testicle; while the
outer one contained at its base, eggs and egg-germs, and ought therefore to
be taken for an ovary.®

The larger Lumbricini appear to be without copulatory organs, the
collar situated back of the genital orifices, taking their place. With many,
it is situated chiefly on the back, but terminates on the belly with two long
lateral swellings, which, during coition, seize those of the other individ-
ual.® This collar, moreover, is composed of a mass of glandular follicles,
which copiously secrete, during the sexual period, a white, viscous liquid.
It is then very fully developed, but at other periods it is scarcely visible.
The belt which is developed near the genital openings of the smaller Lum-

1 With Lumbricus terrestris , the two anterior
genital openings are male, and the two posterior,
female. These have been figured by Montigre
(loc. cit. fig. 2, a. c.), Leo (De Struct. Lumbr. ter-
restr. Tab. I. fig. 2), and by Morren (loc. cit.
Tab. III. fig. 2). With Saenuris , and Nats , I
have also found these two pairs of genital openings.

2 This invagination of the testicle in the ovary
has been distinctly observed by me with Saenuris
variegata , and Nais proboscidea. From //.
Meckel's late researches upon the very compli-
cated genital apparatus of Lumbricus terrestris , it
appears that there are three pairs of seminal vesi-
cles and testicles ; these last being intimately joined
with as many ovaries ( Muller's Arch. 1844, p.
480, Taf. XIII. fig. 12). It is probable that here
the testicles and ovaries are also invaginated, and
that the vesicles which have usually been taken for
testicles are only vesiculae seminales •, see Mor-
ren , loc. cit. p. 175, Tab. VII.-X. and Treviranus ,
in his Zeitsch. f. Physiol. V. p. 154, Taf. VII. How-
ever, as yet I have been unable to trace to their ter-
mination, the excretory ducts of the testicles and
ovaries which are invaginated together.

This point is all the more difficult, for, as Dug is
appears to represent (Ann. d. Sc. Nat. XV. 1828,
p. 328, PI. IX. fig. 2, or Isis, 1830, Taf. III.
Tab. 9, fig. 2), the vas deferens is probably
invaginated in the oviduct. Many observers have
gone so far as to think that the eggs having escaped
from the ovary, and fallen into the cavity of the
body, pass gradually to its posterior portion, and
are there evacuated through invisible openings.
On this account, several of them have taken for
eggs and embryos, the collections of horny spines,
and vibrios, which are often found in these animals.
See above, § 145, note 1 ; and E. Home , Lect. on
Comp. Anat. IV. 1823, PI. CXLIX.

1 have always been astonished that, at the epoch
of procreation with Saenuris , Euaxes , and Nais,
the two anterior genital openings should communi-
cate with two caeca which contain sperm and long

bundles of spermatic particles, but never their cells
of development. Dugis has made a similar obser-
vation with his Nais Jilif or mis (Ann. d. Sc. Nat.
loc. cit. p. 320, PI. VII. fig. 2), only he does not
specify the contents of the organs. Menge , also,
has observed these two caeca with Euaxes. but he
unhesitatingly regards them as testicles ( Wieg -
mann’s Arch. 1845, I. p. 32, Taf. III. fig. 2, aa.
fig. 3). Never having seen any connection between
these caeca and the testicles behind them, I am
disposed to think that the two posterior genital
openings of some Lumbricini, are the common ori-
fices of the invaginated testicles and ovaries, while
the anterior caeca, which are filled at certain times
with sperm, are two isolated Receptacula seminis.
During the mutual copulation, the sperm will pass
from the testicles into these reservoirs, in order to
be used during the subsequent deposition of the
eggs.

From Hojfmeister's description (Die bis jetzt
bekannt. Arten aus der Familie der liegenwiimier,
1845, p. 15) of the copulatory act with Lumbricus
agricola , it would appear that the sperm remains
equally distant from the female organs, being re-
ceived into special fossae, which correspond per-
haps to th z Receptacula seminis. Nais probos-
cidea, although having a pair of genital openings,
has only one testiculo-ovarian canal, both of which
although invaginated, have a very active and inde-
pendent peristaltic action. They are bifurcated an-
teriorly. See Gruit/iuisen (Nov. Act. Acad. Nat.
Cur. XI. p. 246, Tab. XXXV. fig. 4, 5), who has
very correctly perceived the eggs in the bottom of
the ovarian sac, but not the nature of the invagi-
nated testicular canal.

3 With Lumbricus olidus, the two copulating
individuals seize each other so tightly by their col-
lars, that each of these animals completely envel-
ops the other by this organ ; see Hojfmeister , in
fViegmann's Arch. 1843, I. p. 190, and, De ver-
mibus quibusdam, Tab. I. fig. 30.

§ 168.

THE ANNELIDES.

181

bricini at this period, is of an analogous nature. It is also composed of
numerous cutaneous glands, closely aggregated, and extending completely
over many segments of the body.<4) The secretion of this collar is like that
observed with the Hirudinei, probably for the formation of cocoons. But
these cocoons differ from those of the Hirudinei in having the place of their
opening prolonged into a long, narrow neck.®

§ 168.

The Branchiati resemble the Arthropoda in their annulated body, their
distinct head endowed with organs of sense, the structure of their nervous
system, and the development of their locomotive organs; but, from the
simplicity of their locomotive apparatus, and the complete absence of cop-
ulatory organs, they would be carried towards the Zoophytes.

Here the sexes are separate, and the genital organs of both the Capiti-
branchiati, and Dorsibranchiati, appear as simple glandular bodies, ovaries
or testicles, which project from the ventral surface into the cavity of the
body between the fasciculi of the cutaneous muscle.® At the sexual period,
they are filled with eggs, or spermatic particles, although at other times they
can scarcely be seen.®

Neither the testicles nor the ovaries have excretory ducts which open
upon the surface of the body. The sperm and eggs escape into the cavity
of the body, which, during this period is thereby tilled throughout.®

It is possible that the scarcely visible orifices said to be concealed be-

4 Saenuris , Nais , &c.j see Gruithuisen, loc. cit.
Tab. XXXV. fig. 5, b.b.

0 With the large species of Lumbricus , each co-
coon has from one to six eggs (L. Dufour , Ann. d.
Sc. Nat. XIV. 182S, p. 216, PI. XII. B. or, Froriep's
Notiz. No. 472, 1828, p. 149, fig. 13-16 ; and Hojf-
meister , De vermibus quibusdam, Tab. I. and Die
Arten aus der Familie, &c., p. 16, 25, 42). With
the smaller Lumbricini, as with Saenuris , Euaxes ,
Nais, &c., the cocoons contain nearly always five
to eight eggs (Dugas, loc. cit. XV. PI. VII. fig. 5,
Nais ). Most of these cocoons have appendages
by which they are attached to vegetables and other
bodies. Hojfmeister (Die Arten aus der Fam. &c.
p. 42, fig. 9, c.) has figured a very remarkable
husk-shaped cocoon of a new species, Criodrilus
lacuum.

1 See Treviranus , Zeitsch. f. Physiol. III. 1827,
p. 165, Taf. XIII. fig. 17, 18 ( Aphrodite ) ; Rathka,
De Bopyro et Nereide, p. 39, Tab. II. fig. 12, 1.
(Nereis), and Danzig. Schrift. loc. cit. p. 66, Taf. V.
fig. 6, hh. fig. 11, aa. (Amphitrite) ; Grube ,
Zur Anat. d. Kiemenw firmer, p. 16, Taf. I. fig. 1,
2, m. ( Arenicola ), p. 44, Taf. II. fig. 6, y. z. (Eu-
nice); also, Nov. Act. Acad. XX. p. 201, Tab. X.
fig. 13, 15, m. (Ammo try pane). Rathke's and
Grubers opinion upon the presence of both male
and female organs with the same individual is only
an uncertain supposition, founded upon no histo-
logical examination of the parts.

2 This condition of the genital glands after the pro-
creative season, is the reason why, as yet, we pos-
sess so few facts as to their structure. Most ob-
servers, and among them Rathke and Grube , are

* [§168, note 2.] According to Quatrefagcs
(Ann. d. Sc. Nat. X. 1848, p. 46) the sexes are sep-
arate with the Hermella. Both the testicle and the
ovary consist of a delicate areolar tissue adherent to
the inferior internal surface of the general cavity of
the body. These genital organs are evidently tern-

16

of the opinion that the Branchiati, like the Lumbri-
cini, are hermaphrodites. But Quatrefages , from
his knowledge of the development of the spermatic
particles, has recognized separate sexes with the
most different species, thus : Terebella , Sabella ,
Aricinella, Nephtys , Syllis , Glycera, Eunice ,
Sigalion , Phyllodoce , Nereis, and Aphrodite ;
see Comp. Rend. XVII. 1843, p. 423. But before
this, Stannius had concluded that the sexes were
separate with Arenicola, from a difference in the
contents of the cavity of the bodies of different in-
dividuals (Muller'' s Arch. 1840, p. 375). The
glands at the cephalic extremity of the Branchiati
which live incases, and which Grube has regarded
as male genital organs, are certainly not such, for
they occur with both sexes, and do not change in size
during the procreative season. (See § 161, note 4.) *
3 According to Quatrefages (Compt. rend.
XVII. 1843, loc. cit.), the parent sperm-cells
leave the testicle before the formation of the
spermatic particles, which occurs in the cavity of
the body. This is confirmed with Arenicola, by
Stannius (Muller's Arch. 1840, loc. cit.). Ac-
cording to Krohn (IViegmann's Arch. 1845, I. p.
182), the eggs and the spermatic particles, with Al-
ciopa, are developed free in the visceral cavity,
without the intervention of special organs, ovaries
and testicles. Frey and Leuckart (Beitr. &c. p.
88) think they have observed the same fact with
Nereis, Syllis, Phyllodoce, Aonis, Arnmotry-
pane, Ephesia, Hermella, Perm ilia, Fabricia,
and Spirorbis ; they speak of the presence of ova-
ries and testicles in certain Annelides (Aphrodite,
Arenicola) as the exception.

porary, for they are not found in many individuals,
having, probably, quite disappeared from atrophy
after the procreative period. This fact should be
remembered in the study of the genitalia of other
Annelides. — Ed.

182

THE ANNELIDES.

§ 169.

tween the feet of many Branchiati, serve for the escape of the sperm and
eggs.(4) With others, the cavity of the body opens outwardly, probably by
a loss of the last segment, especially with those which are viviparous.®

The water is undoubtedly the medium of fecundation, and receives the
sperm from the males, probably through orifices like those which serve for
the escape of eggs with the female.

With the viviparous Branchiati, water filled with sperm can enter the
body and fecundate the eggs through these same openings.

§169.

The development of the Annelides as far as yet known, occui’S after two
different types ; but it always commences with a complete segmentation of
the vitellus.

I. With the Hirudinei, after the vitellus has divided into many large
cells, a central one becomes distinguished from the others by its still further
division ; this becomes the digestive tube. The others, still dividing, form
a primitive embryonic part in which appears the future ventral and nervous
portion.

The embryo is at first spherical, and ultimately is covered with a delicate
ciliary epithelium. A kind of sucker is then developed upon a certain
point of its surface; this connects with the stomach, and through it is re-
ceived, for food, the albumen surrounding the embryo. It then gradually
lengthens, and, losing its ciliary epithelium before the escape from the egg,
a sucker appears upon the posterior extremity, and it finally becomes
fully developed without a Metamorphosis.®

II. With the Branchiati, there is a complete metamorphosis. The seg-
mentation of the vitellus is uniform throughout, and this last is finally
changed into a round embryo — which, escaping from the egg, swims freely
about like an Infusorium, by means of the ciliated epithelium which covers
its whole body. The embryo then lengthens, and the epithelium disappears

4 According to Milne Edwards ’ observations
upon several Capitibranchiati, as Terebella, Ser-
pula , Protula , &c., the eggs are glued together in
masses by an albuminous substance, and attached
to the stones of the anterior border of their cases ;
see Ann. d. Sc. Nat. III. 1845, p. 143, 161, PI. V.
fig. 1, PI. VII. fig. 23, PI. IX. tig. 42. With Poly-
nog cirrata, on the other hand, masses of eggs are
attached and borne about on the scales of their
body ; see Sars , in Wiegmann’s Arch. 1845, I. p.
13, Taf. I. fig. 12. With the females of Exogone
and Cystonereis , the eggs are situated in longi-
tudinal rows upon the ventral surface *, see Orsted ,
in Wiegmann's Arch. 1845, I. p. 21, Taf. II. fig.
4, and Kolliker , in an as yet unpublished memoir
for the Helvetic Society, titled : Einige Worte zur
Entwickelungsgeschichte von Eunice, von H. Koch
in Trieste, mit einem Nachwort von Kolliker.

[Additional note.] The often-quoted memoir of
Koch and Kolliker on the development of the An-

* [§ 168, note 4.] According to Felix Dujar-
din (Ann. d. Sc. Nat. XV. 1851, p. 298) Exogone
pusilla is androgynous. Beside the well-known
pediculated ovarian sacs on the ventral surface,
each segment of the body, except the first two,
ha3, with this species, a dorsal, fusiform cirrus, in
which are developed spermatic particles. This ob-

nelides has recently appeared in the Neue Schweiz.
Denkschr. VIII.*

5 According to my friend H. Koch of Trieste (in
the MS. just indicated), the eggs of a species allied
to Eunice sanguinea , are developed in the cavity
of the female body, whence the young escape
through a rupture of its posterior extremity.

1 See F. de Filippi, Lettera sopra l’Anatomia, e
lo sviluppo delle Clepsine, Pavia, 183'J, Tav. II. y
Grube , Untersuch. fiber die Entwick. d. Clepsine,
p. 15, Taf. I., and Frey , Zur Entwickel. von. Nephe-
lis vulgaris, in Froriep's neue Not. No. 807,
1846, p. 228. The old observations of E. II. We-
ber ( Meckel's Arch. 1828, p. 366, Taf. X. XI.;
and R. Wagner (Isis, 1832, p. 398, Taf. IV.) agree
very well with those of Filippi

As yet, we possess nothing upon the develop-
ment of Lumbricini, whose young, as is known, like
those of the Hirudinei, leave their cocoons without
undergoing any metamorphosis.!

servation, from its singularity, requires confirm-
ation. — Ed.

t [ § 169, note 1 ] For the embryology of Ne-
mertes, see Desor , Boston Jour. Nat. Hist. VI. p.
1. The general facts accord with those mentioned
in the text. — Ed.

§ 169.

THE ANNELIDES.

183

except upon the belt-like parts of the two extremities. The future ante-
rior extremity is directed in front during the motions of the animal, and
eyes appear upon it ; while the other extremity is gradually divided into
segments upon which bristles and feet appear.®

While the embryos are thus acquiring the adult form, there appear upon
the cephalic extremity and upon the sides of the body, tentacles, cirri, and
branchiae, of forms which vary according to families, genera and species.
The development of the digestive and circulatory organs occurs also with
equal pace,®'

2 See Lovdn in Wiesmann's Arch. 1842, I. p.
302, Taf. VII. (Nereis); Sars , Ibid. 1845, I. p.
12, Taf I. fig. 1-21. ( Polynoe ) ; Orsted, Ibid,
p. 20. Taf. II. (Exogone) ; and Milne Edwards ,
Ann. d. Sc. Nat. ill. 1845, p. 145, PI. V.-IX.,
or, Froricp's neue Not. No. 721, p. 257 (Tere-
belia , Protula , and Nereis). Kblliker (in MS.
already cited) has also observed the development of
an Exogone , and of a Cyst oner e is , an allied ge-
nus. Here the embryo is not formed through a
complete and uniform segmentation of the vitellus,
but, as with the Ilirudinei, the formation is preced-
ed by an irregular division of that portion to be the
ventral and nervous parts. lie, at the same time,
calls the attention to a figure of Milne Edwards ,
representing the development of Protula , from
which it would appear that other Branchiati also are
developed like the Ilirudinei ; see Ann. d. Sc. Nat.
loc. cit. PI. IX. fig. 47.*

3 One ought therefore to be careful about form-
ing distinct genera from these larval Branchiati.
Thus, Sabellina br achy c era, described by Du -
jardin (Ann. d. Sc. Nat. XI. 1839, p. 291, PI. VII.

* [ § 169, note 2.] For the embryology of Poly-
noa, see Desor , loc. cit. p. 12. It agrees closely
with that of N emeries ; see also Max Muller , in
Muller's Arch. 1851, p. 323. — Ed.

fig. 6), is only a larval Terebella , as will be seen
by referring to Milne Edwards' figures of the de-
velopment of Terebella nebulosa (Ann. d. Sc.
Nat. loc. cit. PI. VII. fig. 24, 25). Anisomelus
luteus , of Templeton (Transact. Zool. Soc. II.
1841, p. 27, PI. XV. fig. 9-14), is perhaps only a
young Serpula.

The absence of branchiae and blood-vessels
which Qu at ref ages has noticed with many small
Branchiati of which he has made new genera
(as Aphlebine, and Doyeria , &c.), would lead one
to suspect that they are only larvae ; see Ann. d.
Sc. Nat. 1. 1844, p. 18, or Froriep's neue Not. No.
726, p. 341. H. Koch (see (ibove, § 168, note 5)
has lately observed that the young individuals
found in the body of Eunice are identical with
the Lumbrinereis of De Blainville.

The new animal described bv Muller and Busch
(Miiller's Arch. 1846, p. 104, Taf. V. fig. 3-5, and

1847, p. 187, Taf. VIII. fig. 1-3) under the name
of Mesotrocha sexoculata , appears likewise to
be only a young larva of an Annelid. +

f [ § 169, note 3.] See Quatrefagcs (Sur l’Em-
bryogenie des Ann61ides, in Aim. d. Sc. Nat. X-

1848, p. 153). - Ed.

BOOK NINTH.

ACEPHAIA.

CLASSIFICATION.

§ HO.

The Acephala are principally characterized in having a headless body,
and a very large mantle, which so envelops the body, that there is a spa-
cious and more or less closed cavity in which the oral and anal orifices are
often entirely concealed.

Their body is either wholly asymmetrical, or divided into a right and a
left side. In this last case, the organs, excepting the digestive canal, are
in pairs ; and the two sides are perfectly symmetrical, or one is developed
at the expense of the other. All Acephala are aquatic ; many are perma-
nently attached during life ; others creep about, and a few only can swim
freely. Copulatory organs are wanting throughout.

ORDER I. TUNIC AT A.

Body wholly asymmetrical and so enclosed in the mantle, that there are
only two narrow openings.

Family : Ascidiae.

Genera : A. Compositae.

Didemnum , Diazona, Aplidium, Botryllus, Botryllo'ides, Leptoclinum,
Eucoelium, Synoecium, Polyclinum , Sigillina, Perophora , Pyrosoma.
B. Simplices.

Clavelina, Phallusia , Rhopalaea , Boltenia, Cynthia , Chelyosoma.

Family : Salpinae.

Genus : Salpa.

ORDER II. BRACHIOPODA.

Animals which are symmetrical and bivalved, and whose widely-open
mantle encloses two fringed, arm-like, protractile tentacles.

t

§ 170.

THE ACEPIIALA.

185

Genera : Orbicula, Terebratula , lingula.

ORDER III. LA MELLIBRA NCHIA .

Animals which are symmetrical and bivalved, and whose more or less
closed mantle encloses two pairs of lamelliform tentacles and branchiae.

SUB-ORDER I. MONOMYA.

Family : Ostracea.

Genera : Ostrea, Anomia.

Family : Pectinea.

Genera : Pecten, Spondylus, Lima.

Family : Malleacea.

Genera : Malleus, Perna, Crenatula.

SUB-ORDER II. DIMYA.

Family : Aviculacea.

Genera : Avicula, Meleagrina, Pinna.

Family : Arcacea.

Genera: Area, Pectunculus, Trigonia, Nucula.

Family : Naiades.

Genera : Anodonta, XJnio.

Family : Mytilacea.

Genera: Mytilus, Modiola, Lithodomus, Tickogonia.

Family : Chamacea.

Genera : Chama , Isocardia.

Family : Cardiacea.

G enera : Cardium , Lucina, Hiatella, Cyclas, Piscidium , Tellina, Psam-
mobia, Venus, Cytherea, Venerupis, Mactra, Lutraria, Ungulina.

Family : Pyloridae.

Genera : My a, Soleii, Solenomya, Panopaea.

SUB-ORDER III. INCLUSA.

Family : Teredina.

Genera : Pholas, Teredo.

16*

186

THE ACEPHALA.

$ 170.

Family: Aspergillina.
Genera : Aspergillum , Clavagella.

BIBLIOGRAPHY.

Poll. Testacea utriusque Siciliae eorumque historia et anatome.
1791-95.

J. Rat It ke. Om Dammuslingen, in the Skrivter af Naturhistorie-Sels-
kabet, IV. Kjobenhavn, 1797, p. 139.

Cuvier. Memoire sur l’animal de la Lingule, in the Ann. du Mus.
d’Hist. Nat. I. 1802, p. 69. Memoire sur les Thalides et sur les Bipho-
res, Ibid. IV. 1804, p. 360. Both of these are included in his Mem.
pour servir a l’histoire et a l’anatomie des mollusques. Paris, 1817.
Schalk. De Ascidiarum structura, Dissert. Hal. 1814.

Savigny. Memoires sur les animaux sans vertebres, Pt. II. 1816. Re-
cherches anatomiques sur les Ascidies composees et sur les Ascidies simples.
Also, Isis, 1820, lit. Anz. p. 659, Taf. XI.-XXI.

Carus. Beitrage zur Anatomie und Physiologie du Seescheiden (Asci-
diae), in Meckel's deutsch. Arch. 1816, p. 569, and Nov. Act. Acad. Leop.
Carol. X. 1821, p. 423, Tab. XXXVI. XXXVII.

Cuvier. Memoires sur les Ascidies et sur leur Anatomie ; in the Mem.
du Mus. d’hist. Nat. II. 1815, p. 10; also Isis, 1820, p. 387, Taf. 8, 9.

Chamisso. De animalibus quibusdam e classe vermium Linnaeana. Fasc.
I. De Salpis. 1819.

Bnjanus. Ueber die Athem-und Kreislaufwerkzeuge der zweischaligen
Muscheln. Isis, 1819, p. 42, Taf. I. II., 1820, p. 404, and 1827, p. 752,
Taf. IX.

Eysenkardt. Ueber einige merkwiirdige Lebenserscheinungen an Ascid-
ien, in the Nov. Act. Acad. Leop. XI. 1823, p. 250, Tab. XXXVI.
XXXVII.

Pfeiffer. Naturgeschichte deutscher Land-und Siisswasser-Mollusken.
Abth. II. 1825.

Unger. De Anodonta anatina. Dissert. Vindobon 1827.

Carus. Neue Untersuch ungen iiber die Entwickelungsgeschichte unserer
Flussmuschel, in the Nov. Act. Acad. Leop. XVI. 1832, pt. I. Tab. I.— IV.

Meyen. Beitrage zur Zoologie. Abhandl. I. ; Ueber die Salpen. Ibid,
p. 363, Tab. XXVII.-XXIX.

Owen. On the Anatomy of the Brachiopoda, in the Trans. Zool. Soe. I.
1835, p. 145, PI. XXII. XXIII.; also, in Isis, 1835. p. 143, and Ann.
d. Sc. Nat. III. 1835, p. 52.

Deskayes. Conchifera. Cyclop. Anat. Phys. 1. p. 694. London, 1836.
Esckrickt. Anatomisk-physiologiske Undersogelser over Salperne.
Kjobenhavn, 1840; also, in Isis, 1842, p. 467, Taf. II. III., and : Anato-
misk Beskrivelse af Chelyosoma Mac-Leayanum. Kjobenhavn, 1841.
Milne Edwards. Observations sur les Ascidies composees. Paris, 1841.
Garner. On the Anatomy of the Lamellibranchiate Conchifera, in the
Trans. Zool. Soc. of London, II. 1841, p. 87, PI. XVIII.-XX.

Neuwyler. Die Generationsorgane von Unio und Anodonta, in the
Neuen Denkschrift. der allg. schweizerischen Gesellsch. f. die gesammten
Naturwissensch. VI. 1842, p. 1, Taf. I.-III.

§ 171.

TIIE ACEPHALA.

187

Vogt,. Anatomie der Lingula anatina. Ibid. VII. 1843, p. 1, Taf. I. II.
Van Beneden. Memoire sur l’Embryogenie, l'Anatomie et la Physiologie
dcs Ascidies simples, &c., in the Bullet, de l’Acad. royale de Belgique,
XIII. No. 2.

ADDITIONAL BIBLIOGRAPHY.

Kiilliker. LTeber das Vorkom. d. Holzfas. im Thierreich., in the Ann. d.
Sc. Nat, 1846, P. 193, PI. V.-VII.

Van Beneden. Recherches sur l’Embryogenie, l’Anatomie, etla Physi-
ologie des Ascidies simples, in the Mem. de l’Acad. Roy. de Belgique, XX.
1847.

Frey and Leuckart. Beitragen zur Kenntniss der wirbellosen Thierc
mit besonderer Berucksichtigung der Fauna des Norddentschen Meeres.
Braunschweig, 1847, p. 46, Anatomie des Pfahlwurmes (Teredo navalis).

Deshayes. Exploitation scientifique de l’Algerie, pendant les annees
1840, 1841, 1842. Histoire naturelle des Mollusques, avec un Atlas de
117 Planches. Paris, 1847.

Ed. Forbes and Hanley. A History of British Mollusca and their
Shells. 4 vol. London, 1853. [Contains many anatomical details.]

Dalyell, T. G. Rare and remarkable animals of Scotland, represented
from living subjects, with practical observations on their nature. Vol. II.
London, 1848, p. 138-173, PI. XXXIV.-XLIII. (Ascidiae).

Loren. Om utvecklipgen af Mollusca acephala, Oversigt af k. Vet.
Akad. Fbrhandi. 5te Argangen, Dec. 1848. Stockholm, 1849, p. 233—257 ;
or, its translation in Muller's Arch. 1848, p. 531 ; or, in Wiegmann's Arch.
1849, p. 312.

Quatrefages. Memoire sur le Genre Taret ( Teredo Lin.), in the Ann.
d. Sc. Nat, Xl. 1849, p. 19.

Memoire sur 1’embryogenie des Tarets. Ibid. p. 102.

T. Rupert Jones. Cyclop. Anat, and Physiol. IV. p. 1185, Art. Tuni-
cata.

G. A. F. Keber. Beitr'ige zur Anatomie und Physiologie der Weich-
theire, Konigsberg, 1851. [Devoted to the nervous, circulatory, and res-
piratory systems of the fresh-water Bivalvia.] — Ed.

CHAPTER I.

CUTANEOUS SYSTEM.

§ in.

The body of the Acephala is enveloped in a special mantle, which, with the
Tunicata, is composed of a leathery, cartilaginous, or gelatinous substance,
scarcely at all irritable. (1> But with the Lamellibranchia, and Brachiopoda,
it is composed of a contractile, fleshy membrane. With the Tunicata, it corn-

1 The mantle is leathery with Cynthia . cartilagi- soft with Salpa, and gelatinous with Clavelina , Di-
nous and hard with Phal/usia , cartilaginous and azona , Aplidium , Botrijllus , and Pyrosoma .

188

THE ACEPHALA.

§ 172.

pletely surrounds the body and has only an oral and anal opening ; (2) 3 and
with the compound species, it is continuous with the common substance which
contains the individuals and binds them into more or less regular groups,
and is, therefore, analogous to a corallum. With the Lamellibranchia, and
Brachiopoda, it is more or less open, or even may be wholly divided into
halves ; ® it has here the property, especially upon its borders, of secreting
calcareous matter for the formation of the shell.

§ 172.

With the Tunicata, the mantle is remarkable both for its histological
structure, and its chemical composition. Recent investigations have shown
that, with the Ascidiae and Salpinae, it is composed of Cellulose and there-
fore of a non-azotized substance. (1)

Its anatomical structure is quite complicated. Usually it can easily be
separated into two or three layers, the internal one of which is composed, in
some species, of a lamellated epithelium formed of a single layer of poly-
gonal nucleated cells.®

Its principal mass in both the compound and simple forms of this order,
is formed of a single, or a double confluent layer of' a homogeneous trans-
parent substance, through which are scattered granules, nuclei, groups of
pigment molecules, cells, fibres, and crystals of carbonate of lime, — all
varying according to genera and species, and often differently arranged in
one and the same species.® But in each specie^, they are variously ar-
ranged in the inner portion of this mantle-substance.® In some species

2 These openings are properly only simple ori-
fices of the cavity of the body, and correspond to the
respiratory tubes of certain Lamellibrancliia ; see
below, § 190.

3 With Mya , Panopaea , Pholas , Teredo , As-
pergillum, the mantle is almost entirely closed,
but it has two long fissures at each extrem-
ity with Soleh, Cyclas , Tellina , Mytilus , Litho-
domus and others *, with the Ostracea, Pectinea,
Arcacea, Naiades, and Brachiopoda, it is entirely
open.

1 This important fact was first stated by Carl
Schmidt (Zur. vergleich. Physiol, d. wirbellosen
Thiere. 1845, p. 61), with Cynthia mamillaris ,
and has subsequently been confirmed by Liiwig
and Kolliker , after the most careful investigations
upon the entire order of Tunicata (Corapt. rend.
1846, p. 38). These two authors found this non-
azotized substance, particularly in the different spe-
cies of Phallusia , Cynthia, Clavelina, Diazona ,
Botryllus , Didemnum , Aplidium , Salpa , andPy-
rosoma ; but not with the other Mollusca, nor
with the Annelides, the Helminthes, the Echino-
dermata, the Acalephae, and the Polypi. It is
certainly wanting in the true Infusoria, for Frus-
tulia salina , which Carl Schmidt cites as be-
longing to this order and as containing cellulose,
is evidently a vegetable. Lowig and Kolliker
justly fear, moreover, that this discovery will be
quickly seized by those who deny that there is any
limit between the animal and vegetable kingdom
(see loc. cit. p. 8). They seek, therefore, to oppose
this view by insisting upon the circumstance that
this cellulose is never found in a pure state in the
mantle of the Tunicata, but always combined with
other substances, and that, moreover, no animal
has as yet been found entirely composed of this
substance.

2 Phallusia mamillaris, sulcata, Cynthiapapil-
lata , pomaria, and Salpa bicaudata.

3 This basement substance is homogeneous, and
has the same chemical properties as cellulose.

4 Kolliker has made very detailed investiga-
tions upon the structure of this mantle. He has
kindly allowed me to communicate his results, and
authorized me to make use of them without waiting
for the publication of his work in common with
Lowig (Ueber das Yorkommen von Holzfaser im
Thierreich). According to them, the middle layer
of the mantle of Phallusia monachus, and sul-
cata, Clavelina lepadiformis, and Aplidium
gibbulosum , contains numerous nuclei and star-
like crystals lodged in a transparent structureless
substance. But the external layer of this organ is
filled with very large round cells with very thin
walls, containing no nucleus, but filled with a
transparent liquid. With Clavelina lepadifor-
mis, the peduncle and branches of the whole man-
tle are so crowded with non-nucleated cells, some
round and others elongated, that the basement-
substance is apparently absent. It has therefore
quite the aspect of a vegetable tissue. With
Aplidium gibbulosum, and Botryllus violaceus ,
the cells of the external layer contain carbonate of
lime which ultimately so iricreases that it gives
them a petrified aspect. With Didemnum candi-
dum , these petrified cells have calcigerous rays
and are so numerous that the whole mass of this
compound Ascidian appears filled with white star-
like corpuscles.

According to Milne Edwards, this is true also
of Leptoclinum macu/osum (Observ. sur les As-
cidi£s composes, p. 81, PI. VIII. fig. 2b).

With Diazona vio/aceum, Pyrosoma gigan-
teum , Botryllus polycyclus, Salpa maxima, and
bicaudata , the mantle is without these elegant cells,
and in the basement-substance are found only
granules and nuclei, and with Diazona, in addi-
tion, are pigment-granules, and crystalline points, or
calcareous concretions.

§ 172.

THE ACEPHALA,

189

of this order, the mantle receives, moreover, numerous blood-vessels, or
ramified prolongations of the body of the animal. (S)

These last are spherical or star-like, with Salpa
maxima , and dendritic with Salpa bicaudata ;
with these species they are not soluble in hydro-
chloric acid, and are therefore probably composed
of silex. In the mantle of Botryllus , there are,
in certain places, peculiar flexuous fibres running
in all directions. If these are treated with potassa
they will appear evidently composed of cellulose.

According to Kblliker , the structure of the man-
tle of Cynthia papillata is still more complicated.
Its middle layer is composed of longitudinal and
circular flexuous non-azotized fibres. Between
these lie granules, nuclei, crystals and cells *, these
cells are nucleated, and contain, sometimes pigment
granules, and sometimes daughter-cells which gives
them the appearance of those of cartilage.

Kblliker was unable to determine the structure
of the third and external layer which is horny, for
he had at his disposal only alcoholic specimens
of this Cynthia. He saw however that it united
with the middle layer to form the spines which pro-
ject from the surface of the skin.

In the mantle of Cynthia pomaria , the longitu-
dinal fibres predominate, and between them lie
crystals, round pigment-cells, and other cells which

* [ § 172, note 4.] The presence of cellulose in
animal tissues is a fact of no inconsiderable import-
ance in animal and vegetable physiology. The
subject has recently received much attention from
Schacht {Muller's Arch. 1851, p. 176), and his
conclusions are sufficiently interesting to be pre-
sented in full.

“1. In the mantle of the Ascidiae there is a
substance insoluble in caustic potass, but soluble in
sulphuric acid, which is turned to a beautiful blue
by iodine and sulphuric acid, and which therefore
consists entirely of cellulose. This substance con-
stitutes the interstitial substance of the cells ; in
the mantle of Ph alius ia it is homogeneous, but in
Cynthia it occurs for the most part in a fibrous
form.

“ 2. The mantle of the Ascidiae contains beside
this cellulose, another material which is soluble in
caustic potass, but insoluble in sulphuric acid, and
not colored blue by iodine and sulphuric acid, and
which consequently is not cellulose ; in the mantle
of Phallusia it is only sparingly present, but in
Cynthia and the new Chilian Ascidian, it is much
more abundant and alone constitutes the corneous
epidermis of their mantle.

“ 3. The membrane of the cells in the mantle of
Phallusia does not consist of cellulose, it is colored
brown by iodine and sulphuric acid } it is soluble
in caustic potass, and behaves exactly like an ani-
mal membrane as do the nuclei and vessels.

“ 4. In the mantle of Phallusia , cells abound in
a homogeneous, interstitial substance composed of
cellulose j it is only at the inner margin of the mantle
that fibres composed of cellulose, with nuclei among
them, make their appearance. In Cynthia , &c.,
there are scarcely any traces of cells, while the
nuclei and cellulose fibres abound.

“ 6. A tessellated epithelium, containing no cellu-

are peculiar and filled with yellow corpuscles ; and
finally, a third variety arising from the transform-
ation of the pigment-cells, whose walls are gradu-
ally thickened and ultimately split up into fila-
ments, forming concentric layers around the cell-
cavity. When subjected to potassa, these cell-
membranes are decomposed, like the principal
fibres, into an insoluble, non-azotized substance,
while all the other elements of the mantle entirely
disappear under the action of this agent.

The researches of Koliiker and Lowig up-
on the mantle of the Tunicata, have been r -
cently published in the Ann. d. Sc. Nat. V. 1816,
p. 193, PI. V.-VTI.*

5 Blood-vessels are found in the mantle of vari-
ous Phallusiae ; they are spread out in a reticu-
lated manner, especially in the external layer.
See Cuvier , Mem. sur les Ascidies,-&c., p. 18, PI.
III. fig. 1 {Phallusia mamillaris ) ; Savigny ,
Mem. &c. p. 102, PI. IX. fig. 1. B. {Phallusia.
sulcata ) ,• and Dclle Chiaje , Descrizione e noto-
mia degli animali invertebrati della Sicilia citermr •
Tom. III. 1841, p. 33, Tav. LXXXIV. fig. 2 {Phal-
lusia monachus).

lose, covers the inner surface of the three Ascidiae
which I examined ; the outer surface of the man-
tle of Phallusia appears to have a similar epithe-
lium.

“ 6. There are two essential points of difference
between the modes in which cellulose occurs in the
Ascidiae and in the vegetable kingdom :

“ (1.) In Phallusia , the cellulose constitutes the
inter-cellular substance, but does not, as in plants
form an integral part of the cell-wall itself.

“(2.) In Cynthia and other species, the cellulose
forms free fibres, a form in which it is never ob-
served in the vegetable kingdom.

“ 7. The substance of the mantle of the Ascidiae
is not disintegrated by boiling with caustic potass
and nitric acid, like the vegetable cellular tissue,
into its elementary parts *, there is in it none of the
inter-cellular substance universally present in veg-
etable tissues, and by which the cells are connected
but which inter-cellular material is never composed
6f cellulose, as it resists sulphuric acid, but is solu-
ble in caustic potass, as well as by maceration •, ”
see loc. cit. p. 197, 198. This valuable paper is
accompanied with three colored plates representing
sections, &c., of the mantle-tissues, drawn by the
camera lucida.

From this it is clear that this discovery of cellu-
lose in animals is very far from confounding the
animal and vegetable kingdoms, for whatever else
may be said, the previously established law that
the animal cell-membrane always contains nitrogen,
retains its force.

See, also, the report of Payen on Kblliker and .
Lb wig's paper, before the Institute, in the Compt.
Rend. 1846, XXII. p. 581.

But see for some dissenting views on this subject,
Huxley (Quarterly Jour, of Microscop. Sc. No.-.
1, Oct. 1852, p. 22). — Ed.

190

THE ACEPIIALA.

§§ 173, 174.

§173.

With the Bivalvia, the mantle exhibits (especially near its free borders),
contractile motions upon the slightest touch. These are due to numerous
muscular fibres which traverse in every direction its granular parenchyma,
but are most abundant in the borders. It contains here, moreover, nerves,
blood and aquiferous vessels, and in some species, even genital organs.
The borders of the mantle of the Lamellibranchia are often provided with
very sensitive contractile tentacles ; (1) these are rarely wanting around
the anal opening, — an orifice which serves also for the respiration.® In
many, this anal opening is divided by a septum into a round, superior and
inferior orifice.® The borders of these two orifices are often prolonged
each into a longer or shorter fleshy tube ( Sipho ). These two tubes,

which are often blended together, project considerably out beyond the
mantle and shell, but usually can be wholly withdrawn.®

With the Brachiopoda, the border of the mantle has, instead of retract-
ile tentacles, — hyaline, radiating filaments, which are hollow and deeply
inserted in the substance of the mantle.®

With the Lamellibranchia, and Brachiopoda, the internal surface of
the mantle is covered with ciliated epithelium, which extends also upon the
abdomen, foot, oral tentacles, and branchial lamellae.

This epithelium is of great importance, since it constantly directs cur-
rents of water into the mantle, and thereby food is brought to the mouth,
fresh water to the branchiae, the eggs and sperm are carried away from the
genital openings, and the faeces are rejected outwardly. The existence of
this epithelium makes it clear how these animals can continue to live when
buried in wood or stone.

§ 174.

The mantle of the Bivalvia is covered by two shells, whose infinite vari-
ety of form serves for their zoological classification into genera and species.
These shells are composed for the most part of carbonate of lime so closely

With many of the compound Ascidiae, the body
sends fleshy ramified prolongations into the man-
tle. These have been regarded as blood-vessels by
Savigny (M6m. &c. p. 47, ( Diazona and Botryl-
lus )), and DelLe Chiaje (Descriz. &c. III. p. 34,
Tav. LXXXIII. fig. 13, 15 (Polyclinum viride)) ;
but Milne Edwards (loc. cit. p. 41, PI. VII. fig. 1,
lb. lc. 5'i. ) has regarded them with Botryllus
rotifera , and Didemnum gelatinosum , as hollow
prolongations, — a view entirely assented to by Kol-
liker.

1 With Avicula , Anomia , Pecten , and Spon-
dylus , there are two or three rows of cylindrical
tentacles along the border of the mantle •, with
Lima , these tentacles are highly developed, and
are situated upon the convex edge of the fold of the
mantle. With Mytilus edulis , they are peculiar,
being flattened and digitiform.

2 With the Naiades ((fn-io and Anodonta ), there
are no tentacles around the anal fissure, while the
principal mantle-orifice which is separated from
this last by only a narrow isthmus, has them quite
numerously upon its borders ; see Pfeiffer, Nat-
urg. deutsch. Land-und Siisswasser Mollusken,
Abth. II. Taf. I. fig. 2, 5, 9, p. h. These Naiades
have also a third fissure, which is dorsal and situ-
ated quite distant from the anal one 5 it was first
pointed out by Bojanus. I am y -t unsettled as to
its nature. See Pfeiffer , loc. cit. Taf. I. fig. 5, t.

3 Isocardia, Tridacna, and Chama.

4 With Psammobia , Tellina and Venus, the

siphon is double and very protractile. With Cy-
clas , and Teredo, the two respiratory tubes are
more or less blended together at their base ; and
they are united so as to appear as a single organ
with Mactra , Mya, Panopaca, Solen , Pholas, Lu-
traria, C lavage/ la, and Aspergillum.

In these two last genera, the mantle is prolonged
directly into a siphon without any appreciable line
of separation. It is almost entirely closed, and
beside the siphon and the narrow anterior open-
ing, there is in the middle of its ventral border, a
very small aperture, whose nature is yet with me
doubtful ; see Rupp ell and Leuckart, Neue wirbel-
lose Thiere des rothen Meeres. p. 41, Taf. XII.
fig. 4, a *, and Owen, On the Anatomy of Clava-
gella, in the Transact, of the Zool. Soc. London, I.
p. 270, PI. XXX. fig. 13, 14, or the Isis, 1836, p.
440, 1837, Tab. II. fig. 13, 14.

5 These filaments appear to be composed of a
horny substance. They are smooth and very
small with Terebratula , and very long and jointed
with Orbicula and Lingula.

W’ith Orbicula , each article of the filament is
surrounded with short bristles 5 see Owen, Trans.
Zool. Soc. p. 147, 154, PI. XXII. XXIII. ; or the
Isis 1835, p. 144, 151, Taf. V. YI. •, or in the
Ann. d. Sc. Nat. IIL 1835, p. 55, 66, PI. I. II. ■,
and Vogt, Neue Denkschriften der allg. schweizer-
ischen Gesellschaft fur du gesammten Naturwis-
senschaften, loc. cit. p. 3, Taf. I.

§ 174.

THE ACEPHALA.

191

blended in a homogeneous organic base, that this last is not apparent ex-
cept by the aid of acids. In a few only, does this organic base predomi-
nate over the calcareous matter. a)

The intimate structure of shells is quite varied,® but nearly always an
external fibrous, and an internal lamellated layer may be distinguished by
aid of a simple lens. The external layer appears to have a crystalline
texture, being composed of thickly-set, calcareous prisms, attached perpen-
dicularly or obliquely upon the internal layer. These prisms, however, are
not the result of a crystallization, but, as is shown from their development,®
are only cells filled with lime, and if dissolved in acid, delicate prismatic
cells remain as the organic base. The internal layer is made up of numer-
ous superposed, non-cellular lamellae composed of the organic base, and
arranged intricately in various ways. To the plicae thus formed, and
between which the carbonate of lime is deposited, is due the pearly aspect
of this internal layer. The relative thickness of these layers varies,
sometimes one, and sometimes the other, being the greater.® The exter-
nal layer is undoubtedly secreted by the borders of the mantle, while the
internal is formed by a secretion of its external surface.

The growth of the shell is not continuous, but occurs only at certain pe-
riods of the year ; hence the formation of concentric lines and furrows
upon its surface, analogous to the yearly rings of trees.

The external layer is often colored, either uniformly throughout, or only in
spots ; while the internal one rarely contains any pigment. By examining the
cicatrized wounds which these animals accidentally present, it will appear
plain that this pigment is secreted by the borders of the mantle. For, if
these wounds are situated at a distance from these borders, the shell is
never filled except by a layer of colorless matter.®

In the shells of some Bivalvia there are, moreover, special, narrow ca-
nals, which are either simple and traverse the shell obliquely from within
outwards, or branched in a reticulated manner throughout its whole
extent.®

The shells are not attached to the animal except by muscular insertions
along their borders, and by an epidermis belonging to the borders of the
mantle. This epidermis, composed of a horny, yellowish-brown substance,
stretches from the borders of the shell over its whole external surface,® and

1 The shells of Lingula contain very little lime,
and there is even still less in the flexible valves of
Qrbicula.

2 The microscopic structure of shells has of late
been studied by several naturalists *, see Deshay es ,
Cyclop, of Anat. kc. I. p. 707 Shuttleworth ,
ueber den Bau d. Schalen, &c., in the Mittheil. d.
naturforsch. Geselisch. in Bern 1843, p. 43 •, and
Carpenter , Annals of Nat. Hist. XII. 1843, p.
373, PI. XIII. XIV. and especially the Rep. of the
Brit. Assoc. 1844, p. 1, with many figures.*

3 My a arena? ia forms an exception to this $ the
tooth of its shell contains true prismatic crystals
bound together in a star-like manner 5 see Car-
penter■, Annals of Nat. Hist. loc. cit. PI. XIV.
fig- 8.

4 These two layers, of which the outer one quite
resembles the enamel of the teeth, are very dis-
tinctly seen with Malleus , Perna , Crcnatula ,
Avicula , Meleagrina , Pinna , Anodonta , Unio ,
&c. With Ostrea , and Chama , they alternate
with each other several times. In many Pectinea,

* [ § 174, note 2.] For the complete labors of
Carpenter in this direction, see Cyclop. Anat. and

and Cardiacea, and with Anomia , the fibrous
layer appears to be wholly absent.

5 The formation of pearl occurs only upon the
inner surface of the mantle. It has, therefore, the
same lamellated structure and iridescent property,
as the natural layer of shells.

6 With Terebratula, these canals are quite dis-
tinct— occupying the whole thickness of the shell.
I have observed the same arrangement with Cy-
clas , while with Lingula , they are confined to the
internal layer. By direct light they appear black.
I am yet uncertain whether this color is due to
their extreme tenuity, or to calcareous matter ir»
their interior. If the first, they would be compar-
able to the canaliculi of the dentine of teeth ; but if
the second, to the corpuscles of bone. Carpenter
(Annals of Nat. Hist. loc. cit; p. 384, PI. XIII. fig.
5), has observed that in the shells of Lima rudis ,
those canals are divided and form a kind of net-
work.

1 See Mytilus , Anodonta , Unio, Solen , Lutra -
ria and My a.

Physiol. Art. Shell, IV. p. 556. It is replete with
figures. — Ed.

192

THE ACEPHALA.

$§ 175, 176.

in some species covers even the whole of the siphon.® Very often, how-
ever, this epidermis is worn away upon old portions of the shell, which
is quite striking with those which have lamelliform or pilous prolongations
around the borders of the shell.®

The two shells are joined together partly by a hinge [Car do), and partly
by an elastic tissue [Li g amentum).9 (10) This last, either external or inter-
nal, is antagonistic to the adductor muscles of the shell. It is composed
of elastic fibres, the internal of which, when the shell is closed, are com-
pressed between the borders of the hinge, while those which are external
are lengthened out. In both cases, their natural action is to open the two
shells. (U)

§ 175.

The Terelratidae have a very remarkable internal calcareous support situ-
ated upon the inner surface of the two shells. It consists, first of two delicate
outwardly curved peduncles, which arise from the sides of the two cardinal
teeth situated upon the non-perforated valve ; then there are two other pe-
duncles which are shorter, and arise from a longitudinal ridge upon the
centre of the same valve ; these pass in front and unite in an arcuate man-
ner. The two branches thus formed are abruptly recurved after a short
course, and unite, forming a common arc behind the centre of the shell.®
With many, this structure is much more simple, consisting only of a median
apophysis, from which j^ass off two alar prolongations which are curved at
their extremity.® This structure serves principally for the insertion of
the tentacles.®

CHAPTER II.

MUSCULAR SYSTEM AND ORGANS OF LOCOMOTION.

§176.

The muscles of the Acephala are composed of simple, smooth fibres.

9 With My a, and Lutraria , the epidermis forms
a complete sheath around the siphon.

9 Mytilus hirsutuSy Area barbata , lacerata ,
and ovata.

10 I must omit a description of the various forms
of the hinge and ligament, for they belong properly
to the department of Zoology. The hinge is wholly
wanting with the Inclusa, and the ligament is ab-
sent with the Brachiopoda ; and with Orbicula ,
and Lingula. , both are absent.

The Aspergillina are distinguished from all the
other Acephala, by a singular disposition of their
valves. Their mantle ceases early to secrete the
matter for the shell-formation. The two valves are
then joined at a point, where, most probably, they
would have been articulated, while the mantle
which has only two stflall openings, and its long
siphon with a double canal, is covered with a calca-

reous formation which constitutes, with the two
united valves, the singular tube of these animals.

11 The ligament is internal with Pecten , Spon -
dyluSy Myay Lutrariay and Pholas ; but external
with the Chamacea, Cardiacea, Arcacea, and Nai-
ades. It is half external and half internal with
Malleus, and many other species.

1 Terebratula chilensiSy dorsatay dentatay and
Sou>erbyi ; see Oioew, loc. cit. PI. I. fig. 4.

3 Terebratula rubicunday and psittacea.

3 According to Oweny in those species which
have this apparatus highly developed and bent
backwards, these arches, notwithstanding their cal-
careous nature, are somewhat elastic ; and when
the valves are closed, they are slightly depressed,
and thus may serve in the absence of the elastic
ligament, for the opening of the shell.

v»

§177.

THE ACEPHALA.

193

But Salpa presents a remarkable exception to this, for here the fibres are
striated. (1)

With the Tunicata, the muscular system is most simple, being limited
to a subcutaneous layer, which, with the Ascidiae, envelops like a sac the
body of each individual, and is attached to the skin only at the two open-
ings of the cavity of the body. It is formed of numerous circular and lon-
gitudinal interlaced muscles, among which there are, here and there,
oblique fasciculi.®

With Salpa, this cutaneous muscle consists only of a few isolated bands
bound together by a thin, homogeneous membrane. These bands, which vary
much in number, distance apart, and direction, surround the cavity of the
body, usually in a belt-like manner. They are sometimes straight, some-
times curved, and their extremities never meet upon the ventral surface so
as to form a complete belt, but terminate loosely, or are blended by anas-
tomoses with adjoining bands. Around the two openings of the body, they
form real sphincters.®

By means of this muscle, the Tunicata can enlarge or diminish the cav-
ity of the body, and thus cause the necessary renewal of water for nutri-
tion and respiration, beside ejecting the faeces and products of generation.
The Salpa, by rhythmical contractions of their body (its anterior superior
opening, being closed by a membranous valve), eject water through its pos-
terior opening, and thus are propelled along.

§ 177.

With the Bivalvia, the muscular system is much more complicated. Not
only are muscular fibres scattered through nearly the whole body, but in
certain points, they are so aggregated as to form distinct isolated muscles.

The largest of these muscles are the Adductores of the valves. With
the Lamellibranchia, these consist of a single or a double mass of thickly-
set, parallel fibres, the ends of which are inserted at opposite points of the
two valves. Those species which have two of these muscles are called
Dimya ; here one of these muscles is anterior, and the other, larger, pos-
terior. With the Monomya, there is one muscle alone ; this is large and
situated near the centre of the valves.

With Brachiopoda, these muscles are more complicated, there being four
pairs. Part of these, only, are doubly inserted to the valves, a> while the
rest, which arise from one of the valves, are inserted upon the peduncle.

1 See Eschricht , Over Salperne, &c., p. 64, Tab.
III. tig. 16. These striae are due to a zig-zag pli-
cation, as I have satisfied myself from a specimen
of Salpa zonaria preserved in alcohol. Will has
observed the same in the muscles of other inverte-
brates (Muller's Arch. 1843, p. 359). The mus-
cular fibrillae of Salpa are bound together in prim-
itive riband-like fasciculi which are plicated during
contraction like the frill of a shirt 5 this is easily
seen when one of these fasciculi is observed in an
edgewise position.

2 See Savigny, M4m. &c. PI. V. fig. 1, 2 ( Bol
tenia and Cynthia) ; Delle Chiaje , Descriz. &c.,
III. p. 23, Tav. LXXXIV. fig. 3, 5 ( Phallusia ) ,•
and the Catal. of the physiol. Series, &c., I. PI. V.
( Phallusia ).

3 Salpa cordiformis and zonaria have from
five to seven isolated and equi-distant muscular
girdles ; see Eschricht , loc. cit. Tab. I. III.

17

Salpa cylindrica has ten or eleven of these gir-
dles, the anterior of which converge upon the back
and are curved from before backwards •, see Cuvier ,
Mem. sur les Thalides. loc. cit. fig. 9 ; and Savigny ,
Mem. loc. cit. PI. XXIV. fig. 1. With Salpa mu-
cronata , and maxima , these girdles are blended
together upon the back •, see Meyen , Ueber die
Salpen, loc. cit. Tab. XXVIII. fig. 5, Tab. XXIX.
fig. 2. Salpa pinnata (cristata) is remarkable
for having numerous anastomoses uniting the gir-
dles upon the sides of the body and presenting a
trellis-like aspect ; see Chamisso , De Salpa, fig. 1,
G. II., and Cuvier , loc. cit. fig. 1, 2.

1 Several of these muscles do not always arise
directly from the shell, but from the visceral sac;
so that here their action is not solely for displacing
the viscera, but also for the movement of the valves,
to which this sac is attached.

194

THE ACEPIIALA.

§ 178.

As the points of the insertion of these muscles do not always correspond
with the two valves, (2) 3 their direction is often oblique, or, they sometimes
even cross each other.® Orbicula and Lingula, which want both the liga-
ment and hinge, have this disposition of the adductors which terminate
usually by a delicate tendon, and the contraction of either of these muscles
alone, produces the lateral movements of their valves.

The spirally-pointed tentacles of the Brachiopoda are moved by a par-
ticular apparatus. The fringes of these organs are inserted upon a carti-
laginous tubular prolongation which tapers to a point. This is closed at
both extremities and contains a liquid, which, by the contractions of the
circular muscular fibres, is propelled from the base to the extremity, thereby
unrolling the spiral turns.® These tentacles here certainly take the place
of the elastic ligament of the bivalves, for their extension probably tends
to slightly open the valves.

With the Lamellibranchia, the tentacles which are not rolled, are ar-
ranged quite differently. Like their branchiae, they are scarcely at all
irritable, — this being due to the fewness of their muscular fibres. But in
the mantle these fibres are very abundant, and especially near their free
borders. This is true also of the Siphon, in which both longitudinal and
circular fibres can be easily seen ; here, two very distinct flattened muscles
arise from the base of the siphon and are inserted upon the two valves, ex-
ternal to the posterior adductor muscle : these serve as a Retractor siphonis.

§ 178.

Very many of the Lamellibranchia have a highly-developed organ of
locomotion, — the foot. a) This is a muscular prolongation from the ventral
surface, which passes obliquely forward to be inserted upon the internal sur-
face of the back of the shell, by four, rarely more, tendinous cords.®

These cords surround the abdominal viscera, and becoming gradually
thicker and more muscular, finally blend with numerous, interlaced muscu-
lar fasciculi which compose the foot. This last varies considerably as to its
size and form, and can be protruded a long way out through the open shells,
but may also be wholly withdrawn.®

2 Lingula forms an exception. Here the prin-
cipal adductor is a short, solid muscle, which
stretches straight across from one shell to the
other, at their posterior extremity.

3 This muscular apparatus has been particularly
described and figured by Owen, and Vogt (loc.
cit.) with Terebratula, Orbicula , and Lingula.

With the Terebratula , two pairs of muscles
arise from each valve. The two anterior ones
arising from the imperforate valve, are the longer,
and have their origin back of its centre. After the
crossing of their delicate tendons, they pass
through the opening of the valve and terminate in
the peduncle, together with the two posterior ones
which are short and fleshy, and which arise at the
base of the hinge. Of those of the perforated
valve, the two posterior ones only pass to the
peduncle — the two anterior being attached to the
base of the other valve. With Orbicula , there
are two posterior, and two anterior fleshy muscles,
all of which pass obliquely from one valve to
the other, while the anterior ones sometimes send
off fibres to the short peduncle. In the space cir-
cumscribed by these four muscles, lie four others,
which are small and interlaced, and extend from the

visceral sac to the valves. With Lingula , there
are, beside the principal adductor, four pairs of in-
terlaced muscles, which pass obliquely through the
centre of the cavity of the valves, and are attached
by their two ends to the visceral sac.

*1 Owen , loc. cit. •, and Vogt , Anat. d. Lingula,
p. 8, Tab. II. fig. 16-18.

1 The foot is absent, particularly with those mol-
lusks which are fixed to rocks and other solid
bodies, by a calcareous cement.

2 Usually one pair of these delicate cords passes
above, and another below, and are inserted upon
the valves, quite near the four points of insertion
of the two adductor muscles. This is so with Ano-
donta , Unio , Cardiumy &c. With Isocardia , I
have found a third pair of cords inserted upon the
posterior extremity of the summits of the shelL
These serve not only as Retractores of the foot,
but when this last is fixed to some point, draw the
animal towards it.

3 The laterally-compressed foot of Anodonta , and
Unio , arises, by a large base, from the abdomen,
and has carinated borders. That of Pectunculus
and Venus , is quite similar, but its free border i&
hollowed by a furrow, and is therefore bi-carinated.

<4 179, J 80.

THE ACEPHALA.

195

Most of these animals use this organ to dig in the sand, or to creep along
on soft surfaces. For this purpose, they reach it out in front, and then by
alternate contractions and elongations, drag their body after it. Some spe-
cies can in this way glide freely along like the Gasteropoda, or even seize
hold of aquatic plants. <4) Sometimes this foot is truncate and hollow at its
extremity, and probably, therefore, acts like a sucker.®

f

§ 179.

With many of the Lamellibranchia,(l) the foot appears imperfectly de-
veloped, and has a secretory organ of the Byssus, a part by which these
animals are attached to wood, stone, and other bodies. In this case the
foot is a delicate, protractile, tongue-like body,® capable of a stiffness suf-
ficient for creeping, but used chiefly as a feeler to find the points of attach-
ment by the byssus.® It always points towards the oral extremity, and
upon its inferior surface there is a longitudinal furrow which has a cavity
at its base. The walls of this furrow and cavity secrete the byssus. From
their glandular aspect, they differ much from the rest of the organ, which is
formed of numerous interlaced muscular fibres.®

The bottom of this cavity from which the furrow arises, is regularly di-
vided by numerous delicate, parallel lamellae, from which arises the compact
root of the byssus.® This byssus is, therefore, inserted into the base of the
cavity as are our finger-nails into their matrix. Its base has a fibrous, or
lamellated structure, and passes into a longer or shorter trunk composed of
numerous cylindrical, or flattened filaments,® whose extremities are some-
times discoid.®

§ 180.

Many Eivalvia, which are likewise wanting in locomotive organs, and
have, moreover, no organs of the byssus, attach themselves to bodies in
another and peculiar way. Thus, with Anomia, one of the valves is marked
by a deep fissure, across which, like a short peduncle, a portion of the ad-

With Tellina , Dona: f, and Cyclas , it is very long
and more or less -ridged, and often quite small at
its base.

With Cardium , Nucula , Trigonia , Mactra ,
and Isocardia , it is curved like a hook or knee
from behind in front. With So ten , it is very long,
straight and nearly cylindrical.

1 Cyclas and Pisidium. It is probable that those
species whose foot is furrowed upon its inferior bor-
der ( Pectunculus ), or bent in front {Nucula and
Trigonia ), can also creep like the Gasteropoda.

•'» P kolas.

1 The Malleacea, Aviculacea, Mytilacea, with
Pectcn , Lima , Area , Tridacna , &c.

Quite singularly there exists with Anodonta ,
Unio , and Cyclas , when hatched, a secretory
organ of the byssus ; see below, § 197, note 13.

2 For the byssus-forming organ, see Deshay es ,
Cyclop, of Anat. &c. I. p. 702 5 and especially A.
Muller , De Bysso Acephalorum, Dissert. Berolini.
1836 ; or, his Memoir in Wicgmann's Arch. 1837,
I. p. 1, Taf. I. II.

f The manner in which Mytilus and Tichogo-
nia act in spinning their byssus has been described
by Marion de Procl in the Ann. d. Sc. Nat.
A VIII. 1842, p. 69 ; and by A. Muller , loc. cit.

4 I do not yet clearly understand the true nature
of the walls which secrete the byssus. A. Muller
has designated them as Glandula byssipara , corn-
loosed of round cells. He affirms to have seen at
the base of the furrow of Mytilus edulis , orilices
of the excretory ducts of this gland 5 see JVieg-
7nann',s Arch. loc. cit. Taf. I. iig. 6. On the other
hand, neither J. Muller {Do glandul. structura, p.
39), with Tridacna ; nor 11. Wagner (Lehrb. d.
vergleich. Anat. 1835, p. 271), with Area , and
Pinna , has been able to find these glands.

5 See A. Muller , in IViegmann' s Arch. loc. cit.
Taf. I. fig. 5, c. ( Tichogonia ), and Poll , loc. cit.
II. p. 132, Tab. XXIV. fig. 5-7 {Area).

0 For the intimate structure of the byssus see
the Memoir of A. Muller , loc. cit. With Area , its
form is very remarkable, consisting of a solid, lat-
erally-compressed trunk, carinated above and be-
low, and having filaments upon no portion. With
that of Pinna , on the contrary, its filaments remain
ununited even to the very root.

7 Avicularia and Mytilus; see Poll , loc. cit.
Tab. XXXI. {Mytilus edulis ), and Tab. XXXIV.
'fig. 2 {Pinna muricata).

THE ACEPHALA.

196

§§ 181, 182, 183.

ductor muscle of the other valve® passes, in order to be attached to for-
eign bodies by its smooth, calcareous extremity.

With the Brachiopoda, there is a real peduncle which constantly pro-
jects through an opening near the hinge. It is a soft tendinous or muscu-
lar tube, which is, perhaps, only a prolongation of the mantle.®

*

CHAPTER III.

NERVOUS SYSTEM.

§181.

The nervous system, which has been observed in all the orders of the
Acephala, consists of a central and a peripheric portion.

The first is composed of one, or several (usually three) ganglia ; the second
consists of nervous trunks of variable size, which pass off in the most dif-
ferent directions. When^the number of these ganglia is considerable, they
are arranged in pairs which are situated more or less near the median line,
according to the different regions of the body. The ganglia of each pair
intercommunicate by a transverse commissure of variable length. They
connect, moreover, with others, which are even far removed, by anastomosing
filaments. It is difficult to decide which of these ganglia is the brain. Many
species want a complete ganglionic ring surrounding the buccal cavity.

§ 182.

Prom its extreme softness, the internal structure of the nervous system
of the Acephala is very difficult of study. Its primitive fibres are very
delicate, and are surrounded, in the nervous trunks, by a distinct and very
thin neurilemma. In the ganglia, through which orange-colored granules
are usually scattered,® these fibres pass into a very loose tissue composed
of small transparent vesicles, which probably take the place of the gan-
glionic globules which are so distinct with other invertebrates.®

§ 183.

1. The nervous system is most simple with the Tunicata. It here consists
of a single ganglionic mass, which is subcutaneous, and situated between
the two respiratory tubes.

1 Carefully examined, Anomia will be found to
have three unequal adductor muscles arising from
the imperforate valve. The largest of these, together
with one of the others, passes into the lissure of the
other valve ; while the third is inserted upon the
same valve.

2 It has already been remarked ( § 177), that with
the Brachiopoda the peduncle receives mus-
cles both from the body and from the valves. It
has, moreover, muscles of its own, and ought,
therefore, to be contractile. This contractility is
quite prominent with the very large and long pe-
duncle of Lingula , especially in comparison with

the very short, sucker-like one of Orbicula. Ex-
ternally, it is composed of a thick cartilaginous tis-
sue, while its interior is occupied by a hollow,
muscular cord, composed of longitudinal filaments
see Owen , loc. cit. ( Terebratula), and Vogt , loc.
cit. Tab. I. fig. 1-6 (Lingula).

1 These orange-colored ganglia aro quite distinct
with Unio , and Anodonta.

2 Although the Naiades have very large ganglia,
yet their microscopic examination has furnished no
further results, for neither by the compressorium,
nor by chemical means, can these globules be sep-
arated from the intervening tissue.

§ 183.

THE ACEPHALA.

197

With the Salpinae, the central nervous mass is upon the dorsal surface
in front of the middle of the body. It consists of many closely-aggre-
gated, yellowish ganglia, from which nerves pass off' in all directions. a>

With the Ascidiae, it consists of a single large ganglion, which is easily
found within the muscular envelope, in an angle formed by the oral and anal
tubes. The nerves which pass off’ in different directions from this gan-
glion, belong chiefly to the muscular envelope. Some of them, however,
pass to the organs of sense situated near the two respiratory tubes, and form
around the orifice of that one of them which is buccal also, a complete cir-
cle which corresponds perhaps to an oesophageal ring.®

2. The nervous system of the Brachiopoda is as yet little known.
However, from the presence, in some species, of two or three ganglia about
the oesophagus, it may be concluded that it is analogous to that of the
Lamellibranchia. (3)

3. AVith the Lamellibranchia, the nervous system is the most distinct.®
Its very symmetrical arrangement is prominent, except in the unequivalved

species.

1 Meyen was the first to describe with care this
nervous mass with Salpa ; for, before him, many
other parts of the animal had been erroneously
taken by Savigny (Mem. &c. II. p. 127), and
Chamisso (De Salpa, &c., p. 5), for the nerves and
ganglia ; see Meyen , Nov. Act. Acad. Leop. loc.
cit. p. 394, Tab. XXVII. fig. 5, d. 18 ( Salpa pin-
jiata ), Tab. XXVIII. fig. 5, h k. 12 ( Salpa mucro-
nata). Quoy and Gaimard have also observed a
central nervous system in the dorsal region of se\r-
eral ScUpa ; see Voyage de l’Astrolabe, Zool. III.
p. 559, and the Atlas zoologique of the same, Mol-
lusques, PI. LXXXVI.j or Isis, 1836, p. 113, Tab.
VI.

EschrichVs description is still more minute ; but
he has taken for the ventral surface that portion of
the body in which this lobulated ganglionic mass is
situated 5 see his Memoir, Over Salperne, &c., p.
12, Tab. II. fig. 8, 10, u, v. ( Salpa cordiformis ),
and Tab. III. fig. 22 {Salpa zonaria). See, also,
Belle Chiaje , Descriz. &c. III. p. 45, Tav.
LXXVIII. fig. 3, n. 12 ( Salpa maxima). I am
yet undecided whether the nervous ring, which,
according to Eschricht , is formed by the junction of
the two nerves surrounding the anterior respiratory
orifice, really corresponds to the oesophageal ring.

2 A very detailed description accompanied with
figures of the nervous system of the simple Asci-
diae, may be found in the works of Cuvier (Sur
les Ascidi(*s, &c., loc. cit. p. 24, PI. II. fig. 2 c. 5,
g. III. fig. 2, 3 c. {Cynthia and Phallusia));
Eschricht (Beskrivelse af Chelyosoma, loc. cit. p.
8, fig. 4, c.) 5 Belle Chiaje (Descriz. &c. III. p.
28, Tav. LXXXII. fig. 2, and LXXXIV. fig. 3, 5,
{Phallusia)) ; and Savigny , who has included also
the compound Ascidiae (Mem. &c. p. 32, PI. IX.
fig. 22. XI. fig. lh D\ {Phallusia); also PI.
XXI. fig. 1&. XXII. fig. lh XXIII. fig. I8. D‘. d*.
{Botryllus and Pyrosoma)).

The principal ganglionic mass is always nearer
the anal than the oral tube, and does not give off
branches except at its extremities. The nervous
ring of the Ascidiae, has been observed by both
Cuvier , and Belle Chiaje.

The last of these authors has also mentioned a
particular ganglion which he has observed with
Phallusia mamillaris , in this ring, and which he

* [ § 183, note 4.] See, also, Buvernoy (suite)
Compt. Rend. XXXIV. 1852, p. 665, and XXXV.
1852, p. 119 j also, Frey and Lcuckart , loc. cit.

17*

regards as the brain ; while he has given the name
of Ganglion sympathicum to a principal gangli-
onic mass, lying near the anal tube.

3 Cuvier (Sur la Lingula, loc. cit. p. 8) thinks
he has observed two ganglia at the base of the
arms, but which give off no nerves. Owen (loc.
cit.) has found two ganglia in front of the oesopha-
gus of Orbicula , and one behind it 5 and also two
nerves arising from the two anterior ganglia at-
tended with two arteries which go to the two hearts.

1 The nervous system of the Lamellibranchia
was discovered by J. Rathki. In 1797, he had
well represented the anterior pair of ganglia of An-
odonta (loc. cit. p. 162, Tab. IX. fig. 10, 11). Po/z',
it is true, had already figured the nervous system
of several species of this order (loc. cit. Tab.
XXXVI. fig. 1, n. {Pinna); Tab. VIII. fig. 1, i.
{P ho las) ; Tab. IX. fig. 10, a. {Unio) ; Tab. X. fig.
15, Tab. XI. fig. 1, Tab. XIII. fig. 6, ( Solen ) ; Tab.
XXV. fig. 1, {Area) ; Tab. XXXII. fig. 18, r. {My-
tilusj). But he erroneously took it for a lymphatic
system.

The following works may be consulted upon this
system : Mangili , N uove ricerche zoot. sopra
alcune specie di conchiglie bivalvi, Milano, 1804
(translated in ReiVs Arch. IX. 1809, p. 213, Taf.
xb. {Anodontaj); Brandt , Medizin.Zool. II. p. 310,
Taf. XXXVI. fig. 10,-12 (of the Oyster) ; Garner.
On the Nervous System of Molluscous Animals, in
the Trans, of the Linn. Soc. XVII. 1837, p. 485,
PI. XXIV. ( Ostrea , Pecten , Modiola , Mactra ,
My a, and Pholas) ; and, O11 the Anatomy of the
Lamellibranch. loc. cit. p. 89, PI. XIX. fig. 5 {Fe-
nerupis) ; Keber , De Nervis Concharum, l)iss.
Berolini, 1837 5 Buvernoy , Sur l’animal de PO11-
guline, in the Ann. des. Sc. Nat. XVII I. 1842, p.
118, PI. V. B. fig. 8 5 and, Sur le Systeme nerveux
des Mollusques Acephales bivalves, in the Comp,
rend. 1844, Nos. 22, 25, 1845, No. 8 ; or in Froriep's
neue Not. 1845, No. 731 j Blanchard , Observ. sur
le Systeme nerveux des Mollusques Acephales testa-
c6s ou Lamellibranches, in the Ann. des Sc. Nat.
III. 1844, p. 321, PI. XII. and in Froriep's neue
Not. No. 741 (, Solen , Mactra , and Pecten); and
John Anderson^ Art. Nervous System , in the Cy-
clop. of Anat. III. p. 604.*

p. 46 5 Beshayes , loc. cit. p. 69, PI. VIII. IX. ;
and Quatrefages, loc. cit. p. 63, PI. I. fig. 3, 6
{Teredo). — Kd.

198

THE ACEPHALA.

§ 183.

A. The central nervous mass is composed of three pairs of principal

ganglia, as follows: Par anterius or labiale, Par pas terms, and Par

inferius or abdominale. This last pair is extraordinarily developed with
those species which have a foot, and has, therefore, received also the name
of Par pedale.

The ganglia of the Par anterius are situated one on each side of the di-
gestive canal, and are connected by a filament which extends arcuately
over the circumference of the oral cavity.® They send off two long
nerves, which pass along the back to the Par posterius, which is the larg-
est of all and usually situated upon the anterior surface of the posterior
adductor muscle. Its two ganglia are either blended together, or connected
by a transverse commissure.® In this way, the anterior and posterior
pairs with their commissures form a kind of oesophageal ring which sur-
rounds the base of the abdomen.

The inferior or pedal pair is situated at the point where the base of the
foot is joined to the abdomen. Its ganglia are contiguous upon the median
line, or are blended together into one.® They connect also with the labial
ganglia by two nerves, thus forming a second (esophageal ring.®

Besides these principal ganglia, there are others, smaller, and situated in
various parts of the body. But these are not constant, for their presence is
always due to an unusual development of the muscular system.

B. The peripheric nerves arise almost exclusively from the three pair of
principal ganglia, for the nerves of connection do not usually give off
branches. The few and very delicate filaments which sometimes pass off'
from these last, belong, probably, to the splanchnic system, for the princi-
pal ganglia appear to furnish only sensitive and motory nerves; these are
usually distributed in the following manner :

The Par anterius sends nerves to the anterior part of the mantle,® to
the anterior adductor muscle, and to the tentacles of the mouth and its cir-
cumference.

The Par posterius sends two vex-y large trunks to the bi-anchiae ; also
other nerves to the lateral and posterior pai’t of the mantle, <10> to the pos-
terior adductor muscle, and delicate filaments to the heart and rectum.

5 The length of the arc of this filament of con-
nection depends upon the position of the two labial
ganglia. Thus with Pecten , where these ganglia
are situated unusually in the rear, it is very long
and very arched •, while with Pholas, and Solen ,
where they are close upon the oral opening, it is
short. With Venus , and Mactra , these ganglia lie
so close to each other, that this anastomotic fila-
ment is replaced by a very short, transverse com-
missure.

0 The Par posterius , which, from its relations
to the branchiae, is also called the Par branchiate,
is blended into a single ganglion in those species
whose branchiae are united at their lower part •, as
Unio , Anodonta , Mactra , Mya , Solen, and Pho-
tos. On the other hand these ganglia are separate,
and connected simply by a transverse commissure,
with those whose branchiae are isolated ; as Os-
trea, Pecten, Avicula, Mytilus , Lithodomus,
Modiola, and Area.

7 According to the earlier Zootomists, the Par
pedale was wanting in those species which have
no foot, although careful investigation has shown
that there is a pair corresponding to the Par infe-
rius. I refer to that found with Ostrea ( Brandt ,
loc. cit. Tab. XXXVI. fig. 11, a. o.), directly behind
the labial ganglia, and with Pei ten ( Grube , Mul-

ler's Arch. 1840, p. 33, Taf. 111. fig. 3, g. } and
Blanchard, loc. cit. p. 336, PI. XII. fig. 3, a. b.),
between these ganglia with which it is in connec-
tion by commissures.

8 Of these three ganglia, the Par anterius has
often been regarded as the brain. But others have
rather taken the Par posterius for the principal
nervous mass. For my own part I think that all
three, together with their commissures, correspond
to the pharyngeal system of Gasteropoda.

9 The anterior nerves of the mantle of Solen ,
which is prolonged far beyond the oral opening,
and is strengthened by a muscular mass — have
ten to twelve ganglia lying along the border of the
mantle. With Pecten, the mantle-nerve has also
a small ganglion upon the muscular mass which is
found upon each side of the anterior border of this
organ 5 see Blanchard, loc. cit. p. 333, PI. XII.
fig. 1, f. (Solen), fig. 3, c. (Pecten).

10 In the mantle of Ostrea , Spondylus, Pecten,
Lima , and in general those species in which its
borders have numerous sensitive organs, the
branches of the anterior and posterior mantle-
nerves unite and form a common marginal nerve
whose size depends upon the number of the sensi-
tive organs to which it sends filaments.

$$ 184, 185.

THE ACEPHALA.

199

The siphon and its muscular apparatus receive their nerves also from this
same pair. (1) -

The nerves of the Par inferius being destined chiefly for the foot, cor-
respond in number and size with the degree of development of this organ.
This number, however, varies between two and six for each side.

§ 184.

The Acephala have, certainly, a Splanchnic nervous system, but as yet it
has been found only with the Lamellibranchia ;(1) and even here it is
seen with difficulty and imperfectly on account of the extreme tenuity of
its filaments.

With some species, delicate, lateral filaments pass off from the nerves of
communication, which connect the Par gangliorum inferius and posterius
with the Par anterius ; these may be properly termed sympathetic nerves,
for they are distributed partly to the walls of the digestive canal, and the
heart, and partly to the liver, the gland of Bojanus , and the genital or-
gans.(2)

CHAPTER IV.

ORGANS OF SENSE.

§ 185.

Of the organs of sense with the Acephala, those of Touch are the most
highly developed. They usually consist of conical, or flattened, protractile
prolongations of the skin, which are extremely irritable, covered with cili-
ated epithelium, and often of a deep color.

11 When the two retractor muscles of the siphon
are large, as is the case with Snlcn , Mactra , Ve-
nus, and Cytherea, their two nervous trunks have
several ganglionic enlargements along their
course, connected by transverse filaments ; see
Blanchard , loc. cit. p. 333, PI. XII. fig. 1, 2, d.
(So/en and Mactra).*

1 With the simple Ascidiae, as a sympathetic
system may perhaps be considered the ganglion,
which, according to Schalk (loc. cit. p. 9, fig. 4, g.
q.) is concealed between the intestinal convolutions,
at the posterior extremity of the body of Phallu-
sia, and send off filaments in various directions.
But, as yet, the existence of this ganglion needs
confirmation.

2 Garner , Duvernoy , and Blanchard have seen
the filaments, which issue from the principal ganglia,
enter the vegetative organs ■, but as they could not
further trace them, they hesitate to regard them as
organic nerves. Keber is more positive in favor of
the existence of a sympathetic system with the

* [ § 183, note 11.] See Quatrefages (M£m.
sur le genre Taret. in Ann. d. Sc. Nat. 1849, XI. p.

Lamellibranchia. He has observed (loc. cit. p.
15) that the commissural filaments, which pass
into the Par posterius , give off branches to the
intestinal canal, to the liver, and gland of Bojanus-,
and that those of the Par pedale give off similar
branches to the genital organs ; and also, that
these nerves form several Plexus between these
organs, and from which are given off filaments to
the heart. From this disposition, he ought to con-
clude that these are real organic nerves.

If this is so, the same signification would be
given to the nervous filaments which Blanchard
(loc. cit. p. 335, PI. XII. fig. 1, e.) has seen arise
with an Area , and a Solen , from the two small
ganglia which belong to the commissures of the
Par posterius. More profound Researches upon
the destination of their nerves, must determine
whether the two ganglia situated between the labial
ganglia, with the apodal Lamellibranchia (see above
§ 183 note 7), really correspond to the Par pedale ,
or do not rather belong to the sympathetic system.

63, PI. I.), who has described in detail this system
with the Teredina. — Ed.

200

THE ACEPHALA.

§ 185.

With both the simple and the compound Ascidiae, there are, atthebaseof
the oral tube and at the entrance of the respiratory cavity, numerous fili-
form and sometimes fringed tentacles inserted upon a kind of ring.®
With the Lamellibranchia, there are often conical tentacles around the
respiratory and anal openings of the mantle,® and the orifice of the
siphon.® Among those which have an open mantle, there are many the bor-
ders of whose mantle, either wholly, or only posteriorly,® are provided with
thickly-set conical tentacles.® These receive all their nerves from those of
the mantle.

Instead of these retractile tentacles, the Brachiopoda have long radi-
ating bristles upon the borders of their mantle.® These project a consider-
able way beyond the borders of the valves, and having perhaps sensitive
nerves at their base, they are thus tactile organs like the vibrissae of some
Mammalia.

The oral opening of all the Lamellibranchia is provided, moreover, with
two pairs of contractile, foliated lobes, pointing backwards, which are per-
haps oral tentacles.® Each pair is composed of two lobules, an internal
and an external, which are united at their base, and whose surfaces lie
against each other. Behind, the border of these four lobes is somewhat
thinned, while in front, the two on the same side usually pass into each
other, the external being above, and the internal below, the oral opening.®
The free surfaces of the lobules are smooth and covered with a very thin
epithelium, while the other and opposite surfaces are furrowed transversely
throughout, and the borders of these furrows are fringed with very large
vibratile cilia.®

As tactile organs, may be mentioned the two remarkable arms which,
with the Brachiopoda, are spirally rolled up near the oral opening. The
long, pectinate fringes upon their borders are united at their base by a soft,
hollow membrane which is probably contractile, and is provided with vibra-
tile cilia. (10j

1 See the figures in Savigny , M£m. &c. loc. cit.

2 Cardium ., Chama , Tridacna , and Isocardia.

3 Solen, Pholas , Aspergillum , Mactra , Venus ,
Donax, &c. With Dnnax trunculus , the respir-
atory tube is remarkable for its ramified tentacles j
see Po/i, loc. cit. Tab. XIX. fig. 15-20.

4 Unio , Anodonta.

5 With Donax , Mactra , and Tellina , this row
of tentacles is single •, but it is multiple with Avic-
ula , Anomia , Ostrea , Pecten , Spondylus , and
Lima.

0 See Owen , and Vogt , loc. cit.

7 As to the oblong organ which, with Salpa cordi-
formis. projects into the cavity of the body as
two parallel cutaneous fold%jbetween the anterior
respiratory opening and the central mass of the
nervous system, I am yet undetermined whether or
not it corresponds to the tactile lobes of the Lamel-
libranchia. It appears smooth upon its free
border, and receives, at its transversely striated
base, two nerves from the principal ganglia. With
Salpa zonaria , a simiiar organ lies directly in
front of the central nervous mass •, see Eschricht ,
Over Salperne, loc. cit. p. 14, fig. 8, 10, 22, t. With
Salpa mucronata , this singular organ is situated
in front of the nervous centre, and has been taken
by Meyen for a male genital organ •, see Ueber die
Salpen, &c., p. 397, Tab. XXVIII. fig. 5-10.

6 Avicularia , Isocardia , Pinna , Cardium ,

Pec tunc ulus , Mactra , Anodonta , Aspergillum ,
&c. But Spondylus and Pecten form, in this re-
spect, an exception. Here, the lobes upon each side,
instead of being continuous, are separated by nu-
merous curiously-branched tentacles which sur-
round the oral orifice and strikingly resemble those
surrounding the mouth of certain llolothurioidae
when contracted j see Poli , loc. cit. Tab. XXII. fig.
8, 13, 14, XXVII. fig. 6, 10.

9 The branchial lamellae of the Lamellibranchia
have these furrows upon all their surfaces, and
in their outward aspect closely resemble these tac-
tile lobes. It is therefore probable that, like the
oral tentacles of the Polyps and Holothurians, they
have a varied function. Thus, they could serve not
only as gustatory organs for the food entering the
mouth, but also as those of ingestion, beside taking
a part also in the respiration.

10 The researches of Cuvier , Owen , and Vogt
(loc. cit.) upon the arms of the Brachiopoda, were
made upon specimens preserved in alcohol.

The relations, therefore, of these organs and
their fringes during life are not known. Muller
also (Zool. Danica,!. p. 4), and Poli (loc. cit. II. p.
190, Tab. XXX. fig. 22, 23), say nothing upon the
motions of the fringes of Orbicula and Terebra-
tula. If they are really contractile and ciliated,
the whole apparatus is quite analogous to that of
the Atcyonellae .

§§ 186, 187.

THE ACEPIIALA.

201

§ 186.

As yet, organs of hearing with the Acephala have been found only among
the Lamellibranchia. They are here feebly developed, consisting only of
two simple round capsules filled with a transparent liquid. Their very thick
and somewhat solid walls are homogeneous and transparent ; they enclose a
vitreous spherical otolite, of a crystalline structure, (1) and composed of car-
bonate of lime. These otolites constantly keep up very singular swing-
ing and rotatory motions, which instantly cease, however, when the capsule is
ruptured.® These auditory capsules when present, are situated in the foot
in front of the pedal ganglia with which they- always communicate,® either
contiguously, or by two auditory nerves which they receive.®

§ 187.

Organs of vision are very common with the Acephala, and always many
in number. With some, they occupy a large portion of the borders of the
mantle ; with others, they are confined to the external orifices of the longer
or shorter mantle-tubes. (1)

1 These organs were first noticed by me with the
Naiades, Cardiacea, and the Pyloridae ; but were
regarded as of a doubtful nature. Since then, after
comparing them with the auditory organs of the
embryos of fish, I am satisfied that they are really
very simple organs of hearing *, see Muller's Arch.
1838, p. 49, and Wiegmann's Arch. 1841, 1. p. 148,
Taf. YI. fig. 1, 2 ( Cyclas cornea) ; or, the Ann. d.
Sc. Nat. X. 1838, p. 319, XIX. 1843, p. 193, PI.
II. B. It appears, moreover, that similar corpus-
cles are found in other orders of these animals.
Thus, Delle Chiaje mentions with Salpa neapoli-
tana , an organ situated above the .nervous centre
which exactly resembles the auditory capsules I
have discovered in the foot of Cyclas. Unfortu-
nately he has neither figured nor carefully described
this organ (Descriz. &c. III. p. 45, Tav. LXXYI.
fig. 1, 1.). Eschricht (Anat. Beskriv. af Chelyo-
soma Macleayanum, p. 9, fig. 4, 6, d. '/. and fig. 5)
has also regarded as an auditory organ a remarka-
ble apparatus which he found near the nervous cen-
tre of a simple Ascidian. This consists of a pyri-
form vesicle filled with whitish matter, and of a
clavate body which has, upon its large end, a fis
sure and two lateral depressions.

Delle Cliiaje's figure (Descriz. Ac. III. Tav.
LXXXII. fig. 4.), of the principal ganglionic mass
of Cynthia papillata , reminds me of the cla-
vate body of Chelyosoma and leads me to think
that this author has confounded it with the nervous
centre! I think that this organ exists generally
with both the simple and compound Ascidiae, for
Savrgny has noticed with Cynthia , Phallusia ,
Aplidium , Polyclinum , Botryllus , Eucoelium ,
Synoecium , Pyrosoma , Ac., two tubercles near the
nervous ring which surrounds the respiratory tube
( Tubercule antirieur et postirieur). And, to
judge from his figure (Mem. Ac. PI. VI. fig. 1^, 2,
4 , h. PI. VII. fig. 2<), of one of these tubercles, with
Cynthia , these organs appear analogous to the cla-
vate body just mentioned. At all events, these
tubercles deserve, with Zootomists, more attention
than has hitherto been given them.

2 These motions are probably due to the ciliated
epithelium lining the cavity of the capsules , see,
below, the auditory organs of the Gasteropoda

3 I have been unable as yet to find these capsules
with the apodal Lamellibranchia, — at least, with
Tichogonia , and Mytilus. They appear to exist,
however, for recently j Deshay es has found them both
in Teredo. Here they were situated at the extrem-

ity of the septa lying between the pericardium and
the elevator of the anus, and upon which the ante-
rior extremity of the .branchiae is inserted 5 see
Comp. rend. 184G, XXII. No. 7 ; or Froriep's
neue Not. No. 813, p. 323.

4 With Cyclas , and Tellina , the auditory cap-
sules are contiguous with the ganglia of the Par
pedale. With Anodonta , XJnio , Cardium , and
My a, they are a little removed.

It is remarkable that these organs appear very
early in the embryos of certain Lamellibranchia
( Cyclas ), while in others ( Anodonta and Unio ),
no trace of them is seen during the embryonic
life.

1 Poli (loc. cit. II. p. 153, 107, Tab. XXII. fig.
1, 4 ; and Tab. XXVII. fig. 5, 14, 15), was the
first to compare to human eyes these remarkable
bodies, which, brilliant as diamonds, lie upon the
borders of the mantle of Pecten and Spondylus,
with this expression : Orelli smaragdino colore
roruscantes. Nevertheless, it is only of late that
these organs have received much attention. Gar-
ner (On the Anat. of the Lamellibr. Conchifer. Ac.
PI. XIX. fig. 1, c. 3) was the first to notice anew
the Ocelli of Pecten. Grant (Outlines, Ac., p.
258) has described those of Pecten and Spondylus
as organs long known. Grube ( Muller's Arch.
1840, p. 24, Taf. III. fig. 1, 2), and ICrohn (Ibid,
p. 381, Taf. IX. fig. 16) have described the struc-
ture of these organs, and, quite recently, Will ( Fro -
riep's neue Not. 1844, No. 622, 623) has treated
this subject most profoundly.

Deshay es is not satisfied of the existence of or-
gans of vision with the Pectinea, while Duvernoy
regards as such the bodies situated on the border
of their mantle (Instit. 1845, p. 52, 88). It is astonisl
ing that Deshay es should have denied eyes to the
Pectinea, where they are so complete. lie could have
better denied them to Phallusia , Area , Ostrea , and
other Acephala. During my last visit at Venice
and at Trieste, I examined living individuals of the
genera Area, Ostrea , Pinna , as well as other Lam-
ellibranchia and various Ascidiae ; but with nil
possible care, I was unable to verify Will's descrip-
tion (loc. cit.) of the eyes of these animals. In
most cases, the bodies which he has described as
eyes, have appeared to me only as simple excres-
cences of the mantle, which are variously colored,
but are wholly without the indispensable optic ap-
paratus for a visual organ.

202

THE ACEPHALA.

§ 187.

Each eye is composed of a ball formed of a fibrous Sclerotica, which is
situated upon a small eminence, or is sunken in a contractile prolongation of
the mantle from which projects a cornea, covered by the general skin. Within
the sclerotica there is a reddish-brown pigment which is continuous in front
into a brownish or bluish-green Iris which has a circular pupil ; while behind,
at the base of the eye, it has the appearance of a kind of Tapetum. This
is composed of staff-like corpuscles, which produce that beautiful emerald-
green appearance of the eyes of certain species.

The Retina surrounds a vitreous body, composed of non-nucleated cells,
and which receives in front a very flattened crystalline lens. The optic
nerves which enter the eye-ball at its posterior part, are, together with those
of the tentacles, received from those of the mantle, and especially from the
marginal branches.®

The following are the modifications which have already been observed
with the eyes of these animals :

With the Ascidiae, there are eight eyes at the entrance of the respiratory
tube, and six of a deep-yellow color at the entrance of the anal tube. They
arc situated in the special fissures around the openings, and in the midst of
a mass of orange-colored pigment.®

With Pholas, Solen, Venus, and Mactra, these organs are very numerous
and non-pedunculated, and are situated at the base of the tentacles sur-
rounding the two orifices of the siphon. With Cardium, the borders of
the orifices of the short siphons have an extraordinary number of protract-
ile tentacles which can be protruded through the open valves, each of which
bears an eye of diamond brilliancy.®

With Tellina, the two borders of the mantle have small, reddish-yellow,
pedunculated eyes, which are quite numerous at the posterior portions.

With Pinna, the anterior part of the mantle near the adductor muscle
has, on each side, about forty brownish-yellow eyes situated, upon short pe-
duncles. But with Area, and Pectunculus, the numerous reddish-brown
eyes, usually sessile, are scattered irregularly over the borders of the
mantle.®

Anomia has about twenty brownish-yellow sessile eyes concealed among
the tentacles, upon each border of the mantle. With Ostrea, the number
is still larger ; for, for more than a third of the length of the mantle, there
is a very small short-pedunculated yellowish-brown eye between every
second tentacle.

But the beautiful emerald-green eyes of the Pectinea are the most re-
markable. They are pedunculate and situated between the tentacles of the
marginal fold of the mantle, being very much more numerous upon the
side of the plane, than upon that of the convex valve.®

2 See Garner , loc. cit. fig. 3 5 Krohn , loc. cit.
fig. 16, and Grube , loc. cit. fig. 2.

3 Phallusia , Cynthia , and Clavellina , accord-
ing to Will) loc. cit. No. 623, p. 102. Grant (Out-
lines, &o., p. 361) has seen, at least with Phallusia ,
these fourteen eyes.

4 See Will , loc. cit. p. 100. The color of the eyes
appears reddish blue with Mactra , and of a
yellowish brown with others.

5 See Will , loc. cit. The pupil is an elongated
oval with Pinna. With Pectunculus pilosus ,

the very numerous eyes are partly isolated, and
partly grouped in twenties and thirties.

a Beside the figures already cited, all of which
belong to Pecten and Spondylus , see also those
which Delle Chiaje (Descriz. &c. Tav. LXXV.
LXXVI.) has given of the eyes of Pecten. In this
same genus, Will has seen sixteen to twenty-four
of these organs upon the convex portion of the
mantle, and thirty-five to forty-five upon the plane
portion ; and with Spondylus gaederopus, sixty
upon the convex, and ninety upon the plane side,.

$$ 188, 189.

THE ACEPHALA.

203

CHAPTER V.

DIGESTIVE APPARATUS.

§ 188.

i

The digestive canal of the Acephala is formed, throughout the class, upon
a single plan. It always consists of irregular convolutions which are sepa-
rated with difficulty, for their walls are generally not covered by a peritoneal
envelope, but are intimately blended with contiguous organs and especially
the liver and genital gland. The oral and anal openings, which are always
present, are not upon the surface of the body, but are situated in a cavity
circumscribed by the mantle.®'

The mouth has always tumid lips and often tentacular appendages. Its
cavity has neither distinct muscular walls, nor any trace of a masticatory
apparatus. It passes either directly, or by a short oesophagus, into a kind
of stomach which gradually contracts into a longer or shorter intestine,
scarcely different from it in its intimate structure. The extremity of the
intestine often projects into the cavity of the body, as a kind of papilla^
upon the end of which the anus is situated. Internally, this canal is lined
throughout with a very distinct, ciliated epithelium.

The food of these animals, which consists of slime and small organized
bodies, is taken into the cavity of the body with the water, and is conduct-
ed to the mouth by the ciliated epithelium which lines this last. In a sim-
ilar manner the faeces are rejected with the refuse water.

§189.

The very feebly-developed digestive canal of Salpa consists only of a
small knob ( Nucleus ) situated in the posterior part of the cavity of the
body. It connects with a furrow formed by two narrow folds situated
along the ventral median line.

This furrow may become a canal by the joining of its borders, and its
posterior extremity, which is a little lateral, opens directly at the entrance
of the intestinal canal which is surrounded with a lip, and ought therefore
to be regarded as a mouth. The folds of this furrow arise directly behind
the anterior respiratory orifice, and are very probably covered with cilia,
by which, solid particles of food taken into the body during respiration, are
borne towards the mouth.®

1 With many Acephala, as with the Ascidiae and
Salpinae whose mantle is entirely closed with the
exception of the two respiratory orifices, it is only
in an improper manner that the terms oral and
anal can be given to these orifices.

1 With Salpa cordiformis , and maxima, I have
seen this furrow quite distinctly. It appears to be
present in all species. Cuvier has already men-
tioned and figured it (Mem. sur lesThalides, &c.,
p. 12, fig. 1, 2, 3, &c., </'.), and it has also been no-
ticed by Savigny (Mem. &c. p. 124, PI. XIV. fig.

1, 2, 1.), and Eschricht (Over Salperne, p. 26,
fig. 4, 8, 18, m.) 5 but they describe it as a dor-
sal furrow and a dorsal fold, for they have taken
the abdominal cavity of these animals for the back.
That of Salpa gibbosa is quite distinctly figured in
the Catalogue of the Physiological Series, &c., I.
PI. VII. fig. 1, k. This furrow corresponds, prob-
ably, less to an open oesophagus, than to the ten-
tacle-furrow which, with all the Lamellibranch-
ia, is situated upon the two sides of the mouth.

204

THE ACErnALA.

$ 189.

*

The intestinal canal is short, without a distinct stomach, and somewhat
spirally convoluted.® Its extremity opens by a large anal orifice near the
mouth.®

With the Ascidiae, the intestinal canal is quite distinct. The mouth is
situated in the respiratory cavity, far removed from the so-called oral tube,
or more properly speaking, the respiratory orifice. It is surrounded with
thick lips, and has at its posterior extremity with many species, a semi-canal
• closely resembling, and undoubtedly of the same signification as the ventral
furrow of Salpa. This canal is formed by two narrow folds arising below
the circle of teutacles which surround the interior of the oral cavity ; it passes
along the large curvature of the respiratory cavity, and rising upon its oppo-
site side, ends, after a longer or shorter course, below the oral cavity.® The
mouth opens into a short oesophagus, and this last ends in a long or round
stomach, which is often quite circumscribed and plicated longitudinally
on its inner surface.® The intestine passes first towards the base of the
body by a short arch, then by a longer one it rises towards the mouth,
and thence passes to the anal tube, opening, by a fringed anus, sometimes
close behind the mouth, and sometimes further below it.®

With the Brachiopoda, the mouth is simple and concealed between the base
of the two tentacular arms. With Terebratula, the oesophagus is very long and
curving, opening into a large stomach ;(7) but with the other Brachiopoda,
the stomachal dilatation is wanting, and the intestine is simply convoluted.
With Orbicula, and Terebratula , the intestine is short, and has only a single
convolution which passes to the right and terminates in a lateral anus hid-
den between the lobes of the mantle. But with Lingula, it is much longer,
and its turns are quite numerous ; the anus here is lateral also, and opens
through a small papilla which projects from the cavity of the body into
that of the mantle.®

With the Lanxellibranchia the intestinal canal is highly developed, but
always buried in the midst of other abdominal viscera. The mouth, situated
at the bottom of the cavity of the mantle, and beneath the anterior adduc-
tor muscles, is surrounded by two pairs of tentacles in the form of tactile
lobes; these often form a furrow leading to the mouth, and along which pass
the particles of food drawn in by the cilia.® The mouth opens, either

2 See Home , Lect. on Comp. Anat. II. PI.
LXXII. {Salpa Tilesii).

3 For the oral and anal orifices of Salpa , see the
figures of Cuvier , ancl Savigny , loc. cit. Some
species however differ from the descriptions here
given. Thus, according to a preparation in Hun-
tePs Museum, the intestine of Salpa gibbosa has
two caecal appendages {Home, Lect. &c. PI. LXXI.
fig. 2, 3, and Catalogue of the Phys. Series, I. p.
132, PI. VII. tig. 1, 2, i. i.). The intestinal canal
of Salpa pinnata presents a still more remarkable
exception. No nucleus is formed, but the mouth
opens directly into the stomach which is curved
and sends off an intestine in front, and the anal
orifice is situated near the anterior extremity of the
ventral groove ; see Cuvier , loc. cit. p. 11, fig. 2 5
Home, loc. cit PI. LXXIII. fig, 2, and the Catalogue
of the Phys. Series, I. PI. VI. fig. 4.

4 Savigny has described this canal with the most
different Ascidians as a Sillon dorsal ; see the
figures (loc. cit. PI. VI. &c.) of Cynthia, P/iallu-
sia, Diazona, Synoicum , Aplidium, Eucoelium,
Polyclinum, Botryllus, Pyrosoma, fyc.

Carus also has called the attention to this canal
with Cynthia microcosmus (Nov. Act. Acad.
Physico-Med. loc. cit. p. 432, Tab XXVII. fig. 1, 2,

q).

With Phallus ia intestinalis , there is, opposite
this canal and upon the side of the respiratory cav-
ity corresponding to the anal tube, a longitudinal
row of very long thickly-set filaments, extending
even to the oral aperture. Eschricht has seen a
row of similar tentacles with Chelyosoma ; see loc.
cit. p. 10, fig. 4, 6, z.

5 The stomach is elongated with Bo/tcnia, Phat-
lusia, Cynthia, Sigillina, and spherical with
Aplidium, Eucoelium, &c. Its longitudinal folds
are often very distinctly marked externally by deep
grooves, as is the case with Sigillina , Aplidium ,
and Botryllus ; see for this, Savigny , loc. cit.
According to him also there is a small caecum at
the base of the stomach with Botryllus Schlos-
seri, and polycyclus ; see M6m. &c. p. 201, PI.
XX. fig. 52, PI. XXI. fig. I4, c.

0 Upon the course of the intestine with the Asci-
diae, see Cuvier, Savigny, and Home, loc. cit, PI.
LXXIV. and the Catal. of the Phys. Ser. I. PI. V.
{Phallusia).

1 See the figure given by Owen , loc. cit.

8 For the intestinal canal of several Brachio-
poda, see Cuvier, Owen, and Vogt, loc. cit.

9 With Cardium, Isocardia, Avicula, Ac., these
two pairs of gustatory lobules are very distinctly
seen passing towards the mouth by as many lateral

*

§ 190.

THE ACEPHALA,

205

directly, or by a short oesophagus, a0) into a large stomach lined with numer-
ous papillae and apparently perforated by many biliary canals. The
intestine, when short, forms a single arch only ; but when long, it has many
convolutions ; it terminates in a rectum which lies along the dorsal surface
of the abdomen, (U> and passes between the lobes of the mantle, under the
hinge and above the posterior adductor muscle, finally terminating above in
a ciliated anus, situated upon a small prominence. (ba With the majority
of this order, the rectum traverses the heart. (13) There is often, near the
pylorus, a long caecum11'1' extending between the convolutions of the intes-
tine to the lower extremity of the abdomen, and which contains, through its
whole extent, a cylindrical transparent cartilaginoid body — the so-called
crystalline-stalk. (l0) A longitudinal fold extends along the inner surface
of the entire intestine and a large part of that of the rectum, and thereby
the intestinal surface is increased.

§ 190.

The anterior portion of the digestive canal of the Acephala is entirely
without a Salivary gland. (1) The Liver , however, is always present; it is

grooves, whose borders as already mentioned
( § 185) are blended above and below with the oral
orifice. With Pectunculus , and Area , there is a
still more remarkable arrangement.

Their lobules of this kind consist only of two
narrow folds upon each side of the mouth, and be-
tween which is a transverse furrow, resembling the
ventral-groove of Salpa , or the semi-canal of the
Ascidiae. The important part which this appara-
tus serves in the prehension of food, can be seen
by covering those of Anodonta and Unio with a
powdered colored substance.

This powder is carried by cilia from the surface
to the borders of the tentacles, thence upon their
transversely grooved internal surfaces even into the
angle formed by these last, thence into currents of
the grooves, and so direct into the mouth.

10 A distinct but short oesophagus is found with
Area . Chama , Pinna, Cardium, and Mactra.

11 The intestine is short and has a single arch
with Spondylus , Pecten , Area , and Chama. It is
long and has many turns with P kolas , Tellina.
Cardium , Mactra , Pinna, Ostrea, &c.

12 The anus is short and situated directly behind
the anal fissure of the mantle with Unio, Ano-
donta, Cardium , Isocardia , &c. } while with As-
pergillum, Lutraria and Solen , it is situated far
removed from the siphon. With Area, Pectuncu-
lus, Pinna , and Avicula, the rectum passes
around a large portion of the adductor muscle and
ends in front in a papilla, which, in the last two
genera is quite long. With Lima, it ascends a
little way along the anterior surface of the adduc-
tor muscle, and with Pecten and Ostrea, it leaves
the median line upon the back of this muscle and
passes obliquely towards the smaller valve.

13 To this, Area , Ostrea , and Teredo, form an
exception, and especially with the last, where the
intestinal canal is distinguished for several other
peculiarities. Thus, the stomach is double and
anteriorly divided to its base by a longitudinal sep-
tum ; see Home , Lect. &c. PI. LXXX., and Des-
hay es, Comp. Rend. 1846, XXII. No. 7 j or Fro-
riep's neue Not. No. 813.

14 For the caecum of Solen , Mactra, and Car-
dium, see the figures of Garner , On the Anat. of
the Lamellibr. &c. PI. XVIII. fig. 8-10 ; and for
the disposition of the intestinal canal in general,
see the Plates of Poll , loc. cit.

18

According to Owen (Anat. of Clavagella, &c.,
PI. XXX. fig. 16, r.), Clavagella has a very short
and rudimentary caecum.

15 With the exception of Anomia, the crystalline
stem is wanting in all the Monomya ( Garner , loc.
cit. p. 89). But it exists with many Dimya, as
Pholas, Solen, Area, Mactra, Donax , Cardium,
Tellina, Anodonta, Unio, Mya , &c. ; see Poli,
loc. cit. Tab. VII. XIII. XIV. XVI. XIX. XX.
XXIV. With many of these, there is no caecum
and the crystalline stem is situated in the intestine
itself. It has always a cylindrical form, and is of a
decreased size at its lower end, while at the oppo-
site one it is usually divided in several irregular
lobes which project into the cavity of the stomach
and appear to close up the orifices of the biliary
canals. With the Naiades, where the caecum is
wanting, I have found this singular body, which
extends from the stomach into the intestine, com-
posed of a cortical and a medullary portion. The
first which forms a kind of tube, is homogeneous,
transparent, and formed of concentric layers of the
consistence of the white of an egg. The second is
equally homogeneous and transparent, but is of a
more gelatinous nature and contains a quantity of
small granules (Unio), or batons (Anodonta), in-
soluble in acid, which, at the points where most
aggregated, give this organ a whitish color when
examined by reflected light. According to Poll's
description and figure of this organ with Pholas
dactylus, it has an analogous structure with the
other Lamellibranchia (loc. cit. I. p. 47, Tab.
VII. fig. 11). As yet nothing positive can be said
of the fuhetion of this organ. It may be also added
that often Avith some individuals it is looked for in
vain, while with others it is very distinct though
variable as to its development and the number of
layers composing its cortical portion. Ilence it
seems that it disappears at certain times, to be
developed anew.

That of Anodonta as figured by Bojanus (Isis,
1827, Taf. IX. fig. 9, 10) was undoubtedly in the
state of being formed, or disappearing.

1 Cuvier (Sur la Lingule, loc. cit. p. 7, fig. 10,
11, a.), and Vogt (loc. cit.) have regarded the gland-
ular mass which, with Lingula, opens into the di-
gestive canal, as a solitary organ. But Owen (loc.
cit.) is opposed to this view and says that all the

THE ACEPHALA.

206

§ 191.

connected with the walls of the intestine, almost inseparably, and opens
into it through numerous canals.

With the Tunicata, its structure is quite simple, being composed of
small, single, or ramified glandular follicles, thickly-set together and cover-
ing a large portion of the stomach and intestine.®

With the Brachiopoda, there are groups of green follicles removed from
the digestive canal but communicating with it by excretory canals.®

With the Lamellibranehia, this organ is voluminous and composed of
lobes which occupy the upper part of the abdominal cavity. These lobes
are made up of distinct Acini formed of brownish-yellow hepatic cells.®
The biliary ducts which open into the stomach or the anterior part of the
intestine, are always few in number.

CHAPTER VI.

CIRCULATORY SYSTEM.

§ 191-

This system with the Acephala, as well as that of the Mollusca in gen-
eral, is of a higher grade than that of the Zoophytes and Worms, in hav-
ing the movement of the blood due always to a contractile central organ,
or Heart. This heart is, it is true, very simple in some, but then with oth-
ers it is so developed as to contain both auricles and ventricles. It receives
the blood from the respiratory organs and distributes it over the body, and
is therefore an Aortic heart. As to the blood-vessels themselves, the hith-
erto received opinions have been of late quite seriously objected to ; and it
appears very probable that all these animals have only arteries and veins,

glandular appendages of the intestine of Brachi-
opoda are hepatic organs.*

2 The intestinal nucleus of Salpa owes its yellow-
ish-brown color to tljese hepatic organs. But
with Salpa democratica , aud caerulescens , it is
of a beautiful blue color.

Salpa pinnata , whose straight intestine has al-
ready been mentioned, is distinguished also by its
liver which is separated from and runs parallel
with the intestine •, see Cuvier , and Meyen , loc. cit.
This last-mentioned author affirms that he has seen
with this species a kind of green gall-bladder (loc.
cit. p. 389, Tab. XXVII. fig. 19, m.) ; but probably
he confounded the stomach of the animal with its
liver. For the intimate structure of the glandular
layer upon the intestine of Salpa cordiformis ,
see Eschricht , Over Salperne, p. 27, Tab. III. fig.
20. With the Ascidiae, the liver is a simple gland-
ular layer upon the stomach and intestine in the
various species of Phallusia and Diazona ; while
with Cynthia , it is isolated near the pylorus, and
composed of large follicles } see Savigny , loc. cit.
PI. XII. fig. ld {Diazona').

3 With Terebratula , there are two groups of

follicles opening into the stomach 3 with Orbicula ,
these are replaced by a mass of long hepatic ones 5
and with Lingula , by three principal glandular
masses, opening at different points into the intesti-
nal canal 3 see Owen , Cuvier , and Vogt , loc. cit.

4 Poll (loc. cit. Tab. XI. XV. XVI.) has given a
good representation of some hepatic lobes with their
interanastomosing ducts of several species. See
also Bojanus ’ figures of the liver and its ducts
of Anodonta (Isis, loc. cit. p. 757, Taf. IX.).
As to the intimate structure of this organ, I have
found with Cyclas cornea , lacustris , and rivi-
cola , Unio pictorum, and Tichogonia polymor-
pha , short, cylindrical, transparent filaments, a lit-
tle flexed, but projecting stiffly from the base of the
follicles into their cavity. I am yet ignorant as to
their function, but have in vain sought for it, with
Unio batava , tumida , Anodonta anatina, cyg-
nea , Mya arenaria , Cardium edule , and Mytilus
edulis.

For the intimate structure of the liver of Lamelli-
branchia, see //. Meckel {Muller'' s Arch. 1846,
p. 9, Taf. I.) and Karsten (Nov. Act. Nat. Cur.
XXI. p. 302, Tab. XX.).

* [§ 190, note 1.] Frey and Leuckart declare the presence of salivary glands with Teredo nava-
lis j see loc. cit. — Ed.

§ 192.

THE ACEPHALA.

207

which are connected by no capillary net-work except that situated in the
respiratory organs. The blood leaving the open ends of the arteries passes
into the interstices ( Lacunae ) of the parenchyma of the body; thence it is
taken up by the open mouths of the venous radicles. (1) 2

The Blood is colorless and contains many pale, granular globules, which
are indistinctly nucleated.®

§ 192.

With Salpa , the circulatory system is composed of two main trunks, one
upon the dorsal, and the other upon the ventral median line. At the ante-
rior extremity of the body these trunks connect by two arcuate vessels ;
and at the posterior extremity by a single slightly-dilated canal situated
directly in front of the intestinal nucleus. This last-mentioned canal is
divided into several chambers by two or three constrictions, and, from sits
rhythmical contractions, may be regarded as a heart. (1) It is surrounded
with a delicate pericardium,® and by its pulsations the blood is thrown across
the walls of the body in different ways,® thus forming extra-vascular cur-
rents. But it will here be observed that the heart, thus forcing the blood
alternately in one direction and then in. another, will regularly change the
arterial into a venous current, and vice versa.(i)

With the Ascidiae, this system is equally feebly developed. The blood
passes for the most part out of the vessels into the lacunae which often con-
sist of ramified canals resembling vessels. The Heart is always present,
and is surrounded with a very thin pericardium. It consists of a long
canal, which, at both extremities, passes into a vessel which lies loop-like
between the vascular sac and the intestine at the lower part of the cavity of
the body.® Its pulsations quite resemble the peristaltic movements of the

1 This effusion of the blood into the parenchyma
of the body and its return into the veins without
the intervention of capillaries, or in general with-
out walled canals, has been maintained recently, es-
pecially by Milne Edwards (Observ. et expel*. sur
la circul. chez les Mollusques, Comp. Rend. XX.
1845, p. 261), and by Valenciennes (Nouv. observ.
sur la constit. de l’appareil de la circul. chez les
Mollusques, Ibid. p. 750). Their observations
were not limited to Salpa , and the Ascidiae, but
were extended upon Ostrea , Pinna , Mantra , Ve-
nus, Cardium and Solen. See also Ann. d. Sc.
Nat. III. 1845, p.289, 307, *01* Froriep's neueNot.
Nos. 732, 733, 743.

Milne Edwards is about to publish an extended
work on the circulation with the Mollusca. He has
figured from his beautiful injections the partly la-
cunal circulatory system of Pinna ; see Ann. d. Sc.
Nat. VIII. 1847, p. 77, PI. IV.

2 For the blood of Pkallusia , Cynthia , and Ano-
donta , see Wagner , Zur vergleich. Physiol, d.
Blutes lift. I. p. 20, II. p. 40. The blood-corpuscles
of the Naiades have always appeared to me of an
irregular form ; and they run together when placed
in a watch-glass. This is probably due to the fibrin
cementing them together. When treated with ace-
tic acid they become separated again, their contour
becomes very clear and almost imperceptible, and
a hitherto invisible nucleus is seen.

1 See Cuvier , loc. cit. p. 10, fig. 2, p, &c. Ac-
cording to Meyen (loc. cit. p. 375, PI. XXVIII. fig.
1, d.) the heart of Salpa mucronata lias two con-
strictions •, and, according to Eschricht , that of
Salpa cordiformis is divided into four chambers
(loc. cit. p. 26, fig. 8, a).

2 Meyen (loc. cit. p. 376) has denied the pres-
ence of a pericardium with Salpa ; but Cuvier (loc.
cit. p. 10), Savigny (loc. cit. p. 127), and Delle
Cilia je (Descriz. &c. III. p. 43, Tav. LXXVIII.)
affirm the contrary.

3 The direction of these blood-currents in the
body of Salpa is satisfactorily shown by the de-
scriptions and figures of Quoy and Gaimard (loc.
cit.) and especially of Delle Chiaje (Descriz. &c.)

Sars (Faun. litt. &c. p. 66), has also observed
with Sa'pa runcinata , that the blood beyond the
aorta and vena cava, circulates in wall-less pas-
sages.

4 This remarkable alteration of the blood-currents
which is possible only with a valveless heart, has
been observed and described by different observers
in a conformable manner. Before the heart chang-
es the direction of its contractions it remains still
for a short time, and this slackens the course of the
blood-currents in the body a little, before they re-
ceive an impulse in the opposite direction ; see
Van Hassc/t (Ann. d. Sc. Nat. III. 1824, p. 78).
Eschsc/io/tz (. Muller's translation of the annual
report of the Swedish Academy upon the progress of
Natural History, &c., 1825, p. 94), Quoy and Gai-
mard (loc. cit. p. 559, or Isis. 1836, p. Ill), and
Delle Chiaje (Descriz. &c. III. p. 43).

5 For the heart and blood-system of the Asci-
diae, see especially, Milne Edwards (Sur les Asci-
dies composees loc. cit. p. 4), who has indicated the
presence of the heart in Phallusia and Ctave-
lina , as well as in P oiyclinum , Botryllus , Di-
demnuniy Pyrosoma , 6fC.

208

THE ACEPHALA.

§ 192.

intestine ; and, as with Salpa, the direction of the current is changed so
alternately that the two terminal vessels serve in rotation as an Aorta and
a Vena cava.®

The blood not only traverses the lacunae of the intestinal sac, but also
penetrates the walls of the mantle, and even passes into the common sup-
port of the compound forms. In this last case, it circulates in ramified
canals, which, as prolongations of the cavity of the body, extend even into
this portion of the mantle.®

With the Brachiopoda, this system is quite remarkable. The branchial
afferent veins of the mantle do not open into a single heart, but into two
hearts which are situated right and left of the intestinal sac.®

These hearts, by pulsation, throw the blood into the intestinal canal,
which ought therefore to be considered as a common visceral sinus.®

With the Lamellibranchia, the heart, situated at the posterior extremity
of the back, is divided, usually into three chambers, and surrounded with
a large pericardium. Two lateral, triangular, thick-walled auricles receive
the blood from the branchiae and send it into a simple muscular ventricle
which is nearly always traversed by the rectum. Thence the blood passes
into the body by a posterior and an anterior aorta. Its return into the
two auricles is prevented by valves. <10) The walls of these aortae disappear
after considerable ramification, and the blood passes into a system of lacu-
nae which extends through the whole body and forms a net-work of sinuses
and anastomosing canals. (11) The venous blood is received into special

6 This change in the direction of the blood-cur-
rents was first noticed by Lister (Philos. Trans.
1834, Pt. II. p. 365, or Wiegmann's Arch. 1835,
I. p. 309) with Perophora , a new genus of the
compound Ascidiae ; and Milne Edwards has
since confirmed it with Pyrosoma (Ann. des Sc.
Nat. XII. 1839, p. 375), and several other Ascidiae
both simple and compound : see his Observ. sur
les Ascidies simples et composees, p. 7.

These inter-alternating peristaltic and anti-peris-
taltic motions show that the heart of the Ascidiae
is valveless. It is therefore surprising that Belle
Chiaje has described it with valves ; but this is
not the only point in which he differs from other
observers on this subject, for he describes the heart
of the Ascidiae as bifurcated into two auricles ; see
his Mem. kc. loc. cit. III. p. 193, Tav. XLVI. fig.
13, ab. ( Cynthia papillata ), and Descriz. kc. III.
p. 29, Tav. LXXXII. fig. 11, 12 ( PhalLusia in -
testinalis).

7 This circulation of the blood in the common
Ascidian-stock has been observed by Lister (loc.
cit.). Milne Edwards has seen also the ascending
and descending currents in the ramified and coecal
prolongations of the peritoneal sac, in Botryllus ,
Diazona , Didemnum , and Polyclinum ; see Sa-
vigny , Mem. loc. cit. p. 47 Belle Chiaje , Descriz.
&c. ill. p. 34, Tav. LXXXIII. fig. 13, 15 ; and
Milne Edwards , Sur les Ascidies, loc. cit. p. 41,
PI. VII. fig. 1, lb. lc. This last-mentioned author
has also observed that, with Clavelina (Ibid, p.
9. PI. II.), these canals terminate in caeca which
communicate with the cavity of the body, and are
extended into digitiform prolongations upon the ex-
tremity of the peritoneal sac, and herein the blood
moves alternately up and down. The ramified ca-
nals which abundantly traverse the mantle of Phal-
lusia , are, according to authors, real blood-vessels *,
see Cuvier , loc. cit. p. 16, PI. III. fig. 1 •, Savigny ,
loc. cit. p. 102, PI. IX. fig. 1, B., and Belle Chiaje ,

Descriz. &c. III. p. 33, Tav. LXXXIV. fig. 2.
According to Kolliker (Ueber das Vorkommen der
Ilolzfuser im Thierreich. loc. cit.), these multira-
mose vessels which come directly from the heart
and whose extremities are penicillated, appear to be
continuous directly beneath the skin with other
vessels returning by the course of these arteries.

8 See Cuvier , Owen , and Vogt , loc. cit.

9 Owen was the first to notice this analogy of
the circulation of the Brachiopoda with the extra
vascula r one of other Acephala ; see his Lettre sur
1’ Appareil de la circulation chez les Mollusques de la
Classe des Brachiopodes (Ann. d. Sc. Nat. III. 1845,
p. 315, PI. IV., or Froriep^s neue Not. No. 793).

10 For the arrangement of this central part of the
circulatory system, see Poll , loc. cit. Tab. IX. fig.
12 ( Unio ); Tab. XIII. fig. 5 (Solen) ; Tab. XXII.
fig. 10 (Spondylus) ; Tab. XXVII. fig. 8, 12 (Pec-
ten)} Tab. XXIX. fig. 7,8 (Ostrea) ; Tab. XXXI.
fig. 8, 9 ( Mytilus ), and Tab. XXXVIII. XXXIX.
(Pinna). Also Bojanus, in the Isis, 1819, p. 42,
Taf. I. II. (Anodonta) ; Treviranus , Beobacht. aus
d. Zoot. u. Physiol, p. 44, fig. 67 69 (Mytilus and
Anodonta) ; and Garner , Trans, of the Zool.Soc.
II. p. 90, PI. XIX. fig. 4 (Pecten).

An arrangement quite different from this type is
found with Area , whose two auricles are attached
to the two widely-separated ventricles, and send
out on each side an anterior and posterior aorta,
which meet and join upon the dorsal median line ;
see j Poll, loc. cit. Taf. XXV. fig. 2, 3.*

11 This system of lacunae forms, especially in the
mantle, a beautiful net-work of delicate canals
which, with the Naiades, are visible to the naked
eye. It should not, however, be confounded with
another net-work more difficult to be seen, and
which probably constitutes a system of aquiferous
canals, which is easily seen in the mantle, foot and
other parts of the body by inflation. Belle Chi-
aje has called it Rete lymphatico-vasculosurn ,

* [ § 192, note 10.] See also Beshayes , loc. cit. p. 63, 64, &c.y PI. VIII. fig. 1, 2, 3, and Quatrc-
fages , loc. cit. p. 47, PI. I. fig. 7 (Teredo). — Ed.

§§ 193, 194.

THE ACEPHALA.

209

lacunae situated at the base of the branchiae, and into which it thence
passes.

CHAPTER VII.

RESPIRATORY SYSTEM.

§ 193.

With all the Acephala, the blood, just before returning to the heart,
passes through a branchial, or distinctly respiratory organ, which, either
simple or multiple in structure, is always hidden in the cavity of the man-
tle. The renewal of water takes place by special openings of the body, or
through the slits of the mantle, which are often prolonged into two respir-
atory tubes. One of these openings is for the ingress, and the other for
the egress of the water, and their currents carry in and out, respectively,
food and faeces. In the cavity of the mantle, the water circulates in a
definite direction and passes over the branchiae by means of the cilia cover-
ing their external surface.

§ 194.

The Branchiae of the Acephala are formed after four different types: —

1. With Salpa, there is one only of these organs which stretches, from
above downwards and from before backwards, across the cavity of the body.
The water enters through an anterior orifice which is usually valvular, and is
expelled through a posterior opening by the contractions of the body.*"
The branchia itself, which, near the heart, is bent a little in front at its
lower posterior extremity, consists of a narrow band having upon one of
its sides numerous transverse, thickly-set folds.®. Its remaining portion is
flat,® or the lateral borders are rolled up like tubes.® The branchial ves-
sels are ramified in the interior, communicating, at the superior extremity

and has figured it very beautifully ; see his Des-
cm. &c. Tav. LXXV. fig. 6, and Tab. XC. fig. 1,
2 (Mantle of Pecten and Solen ), Tav. LXXXIX.
fig. 11 (foot of a Mactra).

The vascular net-work which Pali (loc. cit. Tab.
XXXVIII.) has figured in the mantle of a Pinna ,
is probably only one of aquiferous canals.

I shall again ( § 195) allude to this confusion
between the blood and aquiferous vessels.*

l These respiratory motions aid also for the lo-
comotion of Saipa i for, when water escapes by the

* [§ 192, note 11.] This lacunal system is well-
marked with Teredo according to Quatrefages ,
who denies that these animals have a proper venous
system. The grounds of this conclusion are, that
these lacunae are always filled by injecting the
18*

posterior orifice, the animal closes the valve of the
anterior one, so that the body is thrown forwards.
On this account the cavity of the body is often
called natatory.

3 See Cuvier , and Savigny , loc. cit.

3 Salpa costata , and maxima.

4 Salpa pinnata , cylindrical octofora. When
the branchia is contained in a tube it has often been
compared to a Trachea ; see Savigny , loc. cit. PI.
XXIV.

heart, and on the other hand, all the other lacunae
and the arterial system beside may be filled by in-
jecting through one lacuna ; see M^moire, loc. cit.
p. 55. — Ed.

TIIE ACEPIIALA.

210

§ 194.

of the branchiae with those of the body, and at its opposite one with the
heart. Externally, it is covered with large cilia.®

2. With the Aseidiae, the walls of the body are, for the most part, lined
with a membranous branchial apparatus. In the place of respiratory or-
ifices, there are, what are usually called an oral and an anal tube. By the first
of these, the water containing food passes directly into that part of the cav-
ity of the body which contains the branchial apparatus, and which is there-
fore called the respiratory cavity. By the second, this cavity is emptied
of the refuse water containing faeces.®

The branchial membrane, which, in some of the simple Aseidiae, <7) forms
numerous longitudinal folds extending entirely over the respiratory cavity,
presents a trellis-like aspect with rectangular meshes.® These meshes which
form prominent lines, have often small fleshy papillae,® and are always pro-
vided on each side with a row of very long cilia which produce regular cur-
rents of water.

Two longitudinal sinuses pass off from the base of the respiratory cav-
ity and ascend along its greater and lesser curvature even to the oral tube,
where they intercommunicate by a circular canal. These sinuses send
numerous transverse vessels into the branchial membrane, where they anas-
tomose vertically and thus form a net-work corresponding to the trellis
just mentioned.

, From the continual changes in the direction of the blood-currents it is
impossible to determine which is the arterial and which the venous of these

sinuses.5 6 7 8 9 (10)

3. With the Brachiopoda, the internal layer of the mantle serves as
a branchia. The internal surface of the halves of this organ is occupied
with a system of very apparent blood-canals.

With Terebratida, and Orbicida, there are four large canals upon the
surface corresponding to the imperforate valve, and two upon the other sur-
face. These arise from two hearts, and are subdivided into numerous mi-
nute branches. Parallel to these last, are others, smaller, and which appear
to communicate with them on the borders of the mantle ; perhaps they are
the branchial arteries, while the larger canals are veins. (11)

With Lingula , the branchial vessels are contained in collar-lilce projec-
tions, giving the inner surface of the mantle a very peculiar aspect. <12)

4. In the cavity of the mantle with the Lamellibranchia, there are two
pairs of branchiae, which, as four lamellae, embrace each side of the abdo-
men, and the foot.<13) The water which bathes them comes in partly
through an opening in the mantle, and partly by a particular respiratory
orifice upon the border of the abdomen, or by the respiratory tube of the
siphon. It passes out through the anal orifice, or by another tube of the
siphon. (W)

5 These ciliated organs were first described by
Meyen , loc. cit. p. 385.

6 With the compound Aseidiae, the arrangement
is such that several individuals are disposed in a
star-like manner about a cavity in which their anal
tubes open.

7 Cynthia microcosmus , momus , &c.

8 See the figures of Savigny , and Milne Ed-
uards, loc. cit.

9 Phallusia sulcata, monachus, intestinalis,
and Diazona violacea ; see Savigny, loc. cit. PI.
IX -XII.

10 See Milne Edwards, Sur les Ascidies compo-

ses, p. 7. Cuvier , and Savigny , had already

partly known this arrangement of the branchial

vessels.

11 Owen, loc. cit.

12 See Cuvier, Owen, and Vogt , loc. cit.

13 The two external branchial lamellae are usu-
ally a little smaller than the two internal ; and this
difference is well marked with Cardium. Accord-
ing to Valenciennes (Comp. Rend. XX. p. 1688,
XXI. p. 511), there is only a single pair of branchiae
with Lucina jamaicensis , and c olumbella, Cy-
therea tigerina, Tellina crassa , uu&Solen radi-
atus. In this last species, they consist only of two
narrow, longitudinal swellings.

14 The ingress and egress of the water through

$194.

THE ACEPHALA.

211

These four branchial lamellae, whose lower border is free while the other
is attached to the viscera, always extend along the abdomen, and not un-
frequently come together above. (15) ^

Each lamella is formed, essentially, by a widely-projecting cutaneous
fold, the two leaves of which are connected by numerous transverse septa, to
which correspond externally as many furrows which pass from the base of
the branchia to its borders. All these furrows have upon each margin a
row of long cilia, which, upon the borders of the branchia, connect with an
ordinary ciliated epithelium. (10) The compartments formed by these inter-
leaved septa are also lined with a very delicate ciliated epithelium, and
connect with the cavity of the mantle at the base of the branchiae. (17)

With an entire group of this order, the branchial structure is quite dif-
ferent from that just described. Externally, these organs appear like ordi-
nary branchiae, but examined more closely it will be found, that, instead of
lamellae, they are composed of numerous thickly-set ribands arranged in
rows.(18) These ribands are formed of two lamellae blended together at
their extremity. Their circumscribing space is without doubt solely for the
lodging of the branchial vessels: for, at their base, there is no orifice anal-
ogous to those found in the other species of this order. The blood collects
at the base of the branchiae in the longitudinal canal, from which the lat-
eral vessels are given olf, at right angles. Thence it passes into the branch-
iae, traversing a trellis-like net-work quite resembling the analogous one of
the Ascidiae.(ia) Another series of lateral vessels serves as the branchial
veins, pouring the blood into other longitudinal canals, whence it passes
into the two auricles of the heart. (-0)

the different orifices of the mantle may be clearly
seen by observing these animals, when they, at rest,
protrude between the valves either their siphon or
the borders of the mantle and tinge the surround-
ing water with coloring matter, which makes the
currents quite distinct.

15 With Unio , Anodonta , Mactra , Cardium ,

Isocardia , Lutraria , &c., the four branchial layers
are united at their posterior extremity. But with
Pecten, Avicula, Area , Pcctunculus , and Pin-
na, they are disconnected and extended backwards
by two free prolongations.

10 These ciliary movements tend to carry the wa-
ter, with the internal branchiae, towards their free
border •, and with the external, towards their base.

17 These orifices of the branchial compartments
are easily seen at the base of these organs ; ex-
cepting, however, those belonging to the two exter-
nal branchiae, which are concealed beneath a kind of
canal formed by the mantle. These two canals,
closed in front, open behind between the end of the
abdomen and the anus into that portion of the cavity
of the mantle leading to the anal fissure or tube, and
which maybe regarded as a Cloaca •, see Unio ,

Anodonta , Venus , Cardium , Isocardia , Mactra ,

&c. With many, as for instance with Unio, and
Anodonta , the compartments of the external bran-
chiae are much more developed than those of the
internal, and their orifices can be closed in a lip-
like manner by the vesicular enlargement of the
septa which limit them on each side. With Pinna ,
the branchiae are quite different. Their leaves are
united by short filaments instead of by septa *, and
thus, although not divided into compartments,
there are orifices at their base which lead into the
interior, and which are situated upon the internal
surface of the internal, and upon the external sur-
face of the external branchiae.

18 This pectinated form of the branchiae has
been observed by Baer ( Meckel's Arch. 1830, p.
340), with Mytilus , and by Meckel (Syst. d. ver-
gleich. Anat. VI. p. 60), with Spondylus , Pecten ,
and Area ; see, also, the Rdgne animal de Cuvier ,
nouv. £dit. Mollusques. PI. LXXIV. fig. 2, a. I
have seen similar branchiae with Pcctunculus .
Avicula , and Lithodomus. Philippi (JVieg-
mann's Arch. 1835, I. p. 274) has seen them even
still more developed with Solenomya.

This peculiar branchial apparatus with Mytilus
has been described with much detail by Sharpey
(Cyclop, of Anat. I. p. 621). I have myself, dur-
ing the autumn of 1847, completely verified the
statements of this author, upon living specimens of
the genera Mytilus, Area , and Pecten , and would
insist here only on a single remarkable fact. Each
riband-like branchial filament has, upon both of
its surfaces, several cap-like papillae by means of
which these filaments are united together in a trel-
lis-like manner. When the branchiae are forcibly
distended, the papillae of the filaments are separ-
ated from each other. But this separation is not
very extended, for there is a cord composed of del-
icate fibres, between each two papillae and binding
them together •, but sometimes, from undue force,
this cord is broken in its middle, and then each
broken extremity appears as a bundle of moving
vibratile cilia which projects from the cavity of the
capsule (see Sharpey , loc. cit. fig. 305, E. a). The
function of this apparatus, which ceases to be visi-
ble when the papillae are united together, is yet
wholly doubtful.

19 Unio, Anodonta Lima , Pinna , Ostrea , &c. •,
see Treviranus , Beobacht. aus d. Zoot. &c. fig. 62,
63, 65 {Ostrea and Anodonta) ; and Poli, loc. cit.
Tab. IX. fig. 17 (Unio).

W For the branchial vessels, see, especially, Bn-

212

THE ACEPIIALA.

$ 195.

§ 195.

It now remains to speak of a particular system of canals traversing in
all directions the body of the Lamellibranchia, which as yet has been
called the aquiferous system, because it is supposed to serve for an internal
respiration like that of the tracheae of insects. (1) But, in the first place,
the existence itself of such a system has been denied, although there are
certain facts in its favor.

When one of these animals is suddenly taken from the water, numerous
fine jets of water are seen to pass from these organs while the animal is
withdrawing its foot and the borders of the mantle within the shell. From
this fact it is evident that these orifices connect with aqueous reservoirs.
But these openings are very small and probably are closely contracted, for
they cannot be discovered either before or after the jetting out of the wa-
ter. (2) Orifices of this kind have as yet been found in a few species only ;
such are those in the extremity of the foot of So!en,(’’) and that singular
tube found. above the pedunculate anus of Pinna.w

The aquiferous canals themselves are not very apparent, being seen only
after injection. This last is easily performed by blowing through a small
tube inserted under the skin. There will then be seen a very beautiful net-
work of canals, which, nearly all of the same size, are spread out under
almost the whole skin and enter the interior of the body by larger canals.
These canals appear to be without walls, and have, in general, the aspect of
simple lacunae traversing the parenchyma of different parts of the body.

By some naturalists, this net-work of canals is regarded as a system of
lacunae circulating the blood ;(5> but when they are inflated, another net-

Janus, Isis, 1819 *, Treviranus , Beobacht. kc. p.
44. anti the beautiful figures of Poll, loc. cit.*

1 Baer was the first to call the attention to this
aquiferous system with the Naiades ( Froriep's neue
N ot. N o. 265, 1826, p. 5) after an analogous one
had been pointed out with the Gasteropoda by
Delle Chiaje. Poll , it is true, had recognized it
before this, but he had taken them partly for tra-
cheae and partly for lymph oi blood-vessels.

Meckel (Syst. d. vergleich. Anat. VI. p. 64)
went certainly too far when he affirmed that these
orifices are only accidental fissures. 1 have been
unable to find the orifices, which, according to Poll
(loc. cit. Introductio, p. 42, 52), are upon the summit
of the cirri of the mantle and lead into a tracheal
system.

3 Orifices of this kind have been described and
figured by Delle Chiaje with So/en siliqua , as
Fori aquiferi (Descriz. kc. III. p. 60, Tav. XC. fig.
!*)• These pores communicate probably with an
aquiferous system which Treviranus has seen in
the foot of Solen ensis (Die Erschein. u. Gesetze

* [ § 194, note 20.] For full details on the branch-
ial vessels of Teredo, and beautifully illustrated,
see Deshayes , loc. cit. p. 69, PI. VII. and Quatre-
fages, Me moire, loc. cit. p. 57, PI. II. See also
Williams, On the Structure of the Branchiae and
Mechanism of Breathing in the Pholades and other
Lamellibranchiate Mollusks, in the Report of the
Brit. Assoc, for the Advancem. of Sc. for 1851, p. 82,
Dis first four conclusions are :

“1. That the blood of all lamellibranchiate mol-
lusca is richly corpusculated.

des organisch. Lebens. I. p. 276). The orifice
which Garner has figured upon the middle of the
foot of Psammobia and Cardium, and to which
he has given the name of Porus pedalis, belongs
undoubtedly to this system *, see Trans, of the Zool.
Soc. II. PI. XVIII. fig. 2, 13, f.

4 I have easily inflated the reticulated aquiferous
canals of this animal by this tube, which, in Pinna
nobilis, sometimes protrudes far beyond the bor-
ders of the mantle, and which Poli (loc. cit. II.
p. 241, Tab. XXXVI. fig. 3, N. fig. 7, Z. and Tab.
XXXVII. fig. 1, S.) has figured as a Trachea.

"> See above §192, note 11. The vascular net-
work which Poli (loc. cit. I. p. 8, Tab. IX.) has in-
jected with mercury in the mantle of a Unio, and
which he regarded as a lymphatic system, belongs
probably to the aquiferous system. The same in-
terpretation ought perhaps to be put upon a san-
guineous net-work which he has figured in the man--
tie of a Pinna (loc. cit. Tab. XXXVIII.). Delle Chi -
aje (Descriz. kc. III. Tav. LXXV. fig. 6, Tav.
LXXVI. fig. 3, 6, and XC. fig. 1, 2, LXXX1X. fig.

u 2. That the branchiae in all species are com-
posed of straight parallel vessels returning upon
themselves.

“ 3. That the heart is systemic and not branchial.

“4. That the parallel vessels of the gills are
provided with vibratile cilia disposed in a linear se-
ries on either side of the branchial vessel, causing
currents, which set in the direction of the current
of the blood in the vessels.” — Ed.

$ 196.

THE ACEPHALA.

213

work of muck smaller canals is seen expanded between and above them,
and which can be only the blood-canals that were already visible before
inflation.® But the existence with these animals of a double system of
lacunae having this interpretation, is attended with many difficulties. For
then it must be admitted that one of these systems contains only water, and
the other blood ; and it is difficult to understand how two kinds of wall-less
canals can traverse the body without passing ihto each other. But then, on
the other hand, if the aquiferous canals are regarded as veins, and the other
canals as arteries, how can this be reconciled with the fact that, in this c.ise,
the blood system would open externally and the blood escape through the
natural orifices, while the water would be mixed with it from passing into
the body?® At all events, this portion of the organization of these ani-
mals still requires a more thorough investigation.

CHAPTER VIII.

ORGANS OF SECRETION.

§ 196.

The relations of the mantle to the secretion of the shell-substance and
the byssus-forming organ, have already been spoken of.(1) It now only

V

11) has given very beautiful figures of the aquifer-
ous system of the mantle and foot of Pec ten , Pin-
na, So ten and Mactra , but has regarded it as a
Rete lymphatico-vasculosum. Milne Edwards
(Compt. Rend. XX. p. 271, or Ann. d. Sc. Nat. III.
1845, p. 300, or Froriep's neue Not. No. 733, p.
99), who has seen these canals in Pinna , Mactra ,
Ostrea , &c., regarded them simply as a system of
lacunae common to all the Acephala.

0 I have seen it thus, at least with Unio , and
Anodonta.

1 DeLle Chiaje (Descriz. &c. III. p. 53) thinks
that, with the Lnmellibranchia, the sanguineous
system opens externally through special orifices.

* [§ 196, note 1.] The means by which the
Teredina penetrate the woody or stony substances
ip which they live, have received some investiga-
tion of late, and I refer here to the subject from its
alleged anatomical relations.

According to Hancock (Proceed. Brit. Assoc,
for the Advancem. of Sc. 1848, or Ann. of Nat.
Hist. 1848, II. p. 225, PI. VIII. or Silliman's
Amer. Jour, of Sc. 1849, VII. p. 288), “On a mi-
nute examination of the surface of the foot of Te-
redo Norvegica it is found under the microscope
to be crowded with minute brilliant points which,
on being compressed, consist of comparatively
large crystalline bodies imbedded within them.
These crystals are numerous and of various sizes
and shapes, chiefly five and six sided, but not by
any means regularly so. They all agree in having
one or more elevated points near the centre. These

1 See above §§ 174, 179. According to Deshay cs,
Teredo has, at the anterior extremity of the body,
a gland concealed between the valves and which
communicates with the mouth of the animal. Its
product would serve to dissolve the wood in which
this animal bores. This glandular apparatus
which, according to Deshayes exists also with
other Teredina which live in calcareous matters,
demands a further examination ; see Comp. Rend.
XXII. p. 38, 300, or Froriep's neue Not. XXXVII.
p. 324, XXXVIII. p. 103.*

bodies are highly refractive, and are for the most
part pretty regularly distributed over the whole con-
vex surface of the foot, but are occasionally congre-
gated in masses.” This author thinks that this, as
also all other boring Mollusks, excavate by means
of these parts which rasp down the substance to be
removed. See as corroborative of these views, Clark
Ann. Nat. Ilist. 1850, V. p. 6. But naturalists
are not agreed on this point, and however it may
be with Teredo , yet with Pholas , other observers
have failed to find these rasping particles in ques-
tion j see a report on the discussion of Hancock's
paper in the Athenaeum No. 1086 3 also Quatre-
fages , M^moire sur le Genre Taret, Ann. d. Sc.
Nat. 1849, XI. p. 33, and History of British Mol-
lusca by Forbes and Hanley , p. 105.

After all, it would seem that it is most probable
that this process is effected by the action of cilia

THE ACEPIIALA.

214

§ 196.

remains to notice a very remarkable organ found in all the Lamellibranehia,
and known as the Gland of Bojanus.

This organ, undoubtedly of a renal nature, is always double, and consists
of a large long sac with glandular walls, and of a dirty-yellow or dark-
green color. It is situated each side of the back between the pericardium
and the inferior adductor muscle, and extends usually upon the sides of
the abdomen to the base of the branchiae.

Quite often these glands are united upon the median line of the back —
their cavities being separated only by a thin septum. They communicate
with the cavity of the mantle by two small openings which have swollen
borders and are situated sometimes at the upper, and sometimes at the lower
end of the sac.®

The usually very thin walls of these two sacs have numerous folds or
plicae, which form compartments or areolae, all of which are covered with
a very delicate ciliated epithelium. The parenchyma of these walls is
composed of a very loose tissue, which, upon the least disturbance, sepa-
rates into small granular cells.® Most of these cells contain a blue-black
round nucleus, to which is due the more or less deep color of these
organs.®

2 With Unio , and Anodonta , these orifices are
at the superior extremity of the renal sacs close
beside the two genital openings’, see Bojanus , Isis,
1819, p. 46, Taf. I. fig. 1 ; Baer , in Muller's Arch.
1880, p. 319, Taf. VII. fig. 1, 2 ; Pfeiffer , Natur-
gesch. deutsch. Land-und Susswasser-Mollusken,
Abth. II. Taf. IL. fig. 19, b. •, and Neuwyler , in
the Neue Denkschr. VI. p. 22, Taf. I. II. They
lie in. the angle formed by the abdomen and the in-
ternal branchiae, and concealed beneath the inter-
nal leaf of these last. They had already been ob-
served by Poli (loc. cit. I. p. 6, Tab. IX. fig. 15,
i. i.), who, however, did not recognize their true
nature.

With Pecten , and Spondylus , these renal sacs,
which are situated in front of the adductor muscle,
have their two orifices at the lower extremity ; see
Garner, Trans, of the Zool. Soc. loc. cit. PI. XIX.
fig. 2, j. {Pecten).

With many, the genital organs open into the
urinary ones. This is so according to Garner (loc.
cit. p. 92), with Tellina , Cardium , Mactra , Pho-
las, and My a. I have very distinctly seen with
Pinna nobilis, the two orifices common to the kid-
neys and genital organs. Their borders were
swollen, and they were situated upon the anterior
surface of the dorsal wall a little in front of the
posterior adductor muscle. They opened into a
very large sac with thin walls which had no gland-
ular structure except at their lower extremity
near the principal adductor muscle 5 see Poli, loc.
cit. Tab. XXXVII. fig. 2, D.

The genital orifices open into the two sacs di-
rectly back of these external orifices. With Myti-
lus edulis , the kidneys have a yet more singular
arrangement 5 their two sacs situated at the base
of the branchiae are open their whole length, so

alone. This would seem inefficient did we not re-
member their unceasing action ; and this view is
the only one which will explain the exact conform-
ation of the excavation to the shape of the body in
all its parts. It is the view of Agassiz , and others,
who have specially examined the subject. I have
here thus noticed the matter in a suggestive point of
view for microscopical anatomists. — Ed.

that by spreading apart the branchiae, the com-
partments and cells of these glands can be distinct-
ly seen 5 see Treviranus. lleobacht. aus d. Zool. u.
Phys. p. 51, fig. 68, b.*

3 It is only recently that the intimate structure
of these organs was known. Neuwyler was quite
mistaken in regarding them as two testicles (loc.
cit. p. 25). He speaks of tubes in which he affirms
that he has seen spermatic particles, but he gives
neither a detailed description nor a figure of one
or the other. I have never been able to find
anything of this kind in the Lamellibranehia. If
the walls of these organs are prepared in any way
for microscopic examination, a part of their paren-
chyma separates into a vesiculo-granular mass,
the particles of which have a very lively dancing
motion. The motions are due to portions of ciliated
epithelium adhering to the cells and granules. It
is in this way, probably, that Neuwyler has been
deceived, taking these moving bodies for spermatic
particles.

4 These round nuclei, usually of a deep brown or
blue color, can easily be seen in the kidneys of
Unio , Anodonta, and Cyclas ; but with the young
individuals their number and size are quite limited,
making the kidneys very pale. They resemble,
moreover, perfectly the bodies contained in the
renal substance of the Gasteropoda (see below).
This analogy is particularly striking with Asper-
gillum vaginiferum , whose renal sacs are tri-
angular and situated between the heart and the
extremity of the rectum, thus resembling in all re-
spects the kidneys of the Gasteropoda, although
Leuckart has taken them for the liver (Neue. wir-
bellose Thiere d. roth. Meeres, loc. cit. p. 46, Taf.
XII. fig. 6, g.).

* [§ 196, note 2.] According to Frey and
Leuckart , the bodies of Bojanus are absent in
Teredo navalis, but these observers think the kid-
neys are present in another part of the body j see
loc. cit. p. 46. — Ed.

$' 197.

THE ACEPHALA.

215

These nuclei are very solid and ought to be regarded as the secreting
bodies. They are sometimes so large as to be visible to the naked eye as
inorganic concretions, and, as they contain uric acid, they may well be
compared to renal calculi.® The walls of these kidneys are surrounded
by a distinct net-work which arises from the large venous reservoir in
which the afferent blood of the body is accumulated. A small portion of
the blood which circulates in the kidneys passes directly to the heart ; but
the rest is emptied into the pulmonary arteries.®

CHAPTER IX.

ORGANS OF GENERATION.

§ 197.

The Acephala throughout, propagate by genital organs. With the
Tuuicata only, is there also observed multiplication by gemmation.

This occurs with the compound and some of the simple Ascidiae, which
remind one of the Zoophytes and more particularly the Polyps„which they
resemble from other conditions of the organization. The buds are always
developed at the lower extremity of the body, appearing first as small pyri-
form projections, covered by the general envelope of the mantle, into which
the circulation is prolonged.

Gradually, an Ascidian is developed upon the round summit of this pro-
jection, while its peduncle is lengthened and somewhat constricted ; this
continues until the body of the new individual is entirely separated from

5 Similar concretions had already been seen and
described with several of the Lamellibranchia by
Poli) who has regarded the kidneys as organs for
the secretion of the lime of the shell ; see his classic
work, Introductio, p. 18, also Tom. II. p. 86,
Tab. XX. fig. 4, 6, k, fig. 12, 13 ( Cytherea chio ),
p. 143, Tab. XXVI. fig. 11, 12, 13, y. [Pectun-
culus pilosus ), and p. 241, Tab. XXXVII. fig. 5,
6, 3, D ( Pinna nobilis).

These concretions were irregular and of a red or
yellow color. I have recently found, in several in-
dividuals of Pectunculus pilosus , amber-colored
concretions, mostly round, of variable size, giving
these two organs the appearance of a fish’s ovary
filled with eggs. Having collected a considerable
quantity of these concretions, I sent a part of them
to Herrn Von Babo of this city, who has favored
me with their qualitive analysis. The result was
that those with a conchoidal fracture were com-
posed principally of phosphate of lime with a trace
of magnesian phosphate, and a small quantity of
organic matter which behaved with nitric acid ex-
actly like uric acid. Notwithstanding Bojanus
(Isis, 1819, p. 46, 1820, p. 404) has taken much
pains to prove that these organs are pulmonary,
yet the view that they are kidneys has found most
support ( Treviranus , in Tiedemann's Zeitsch. f.
Bliys. I. p. 53, and Carus , Zoot. 1834, II. p. 650),

aside from the fact of their containing uric acid
( Garner , Trans, of the Zool. Soc. loc. cit. p. 92, and
Owen , Lect. on Comp. Anat. &c. p. 284), a point
upon which I was not before satisfied.

The chemical composition of these concretions,
however, satisfies me that these organs are truly
kidneys.

0 This is the mode of circulation of the blood
through the kidneys, according to Bojanus , loc. cit.
But the opinion of Treviranus is different. Ac-
cording to him all the blood returning from the
branchiae traverses the glands of Bojanus before
reaching the heart (Beobacht. aus. d. Zoot. &c. p.
49). As these organs are not easily found, it will
be difficult to determine this point positively by
direct observation. It is only by following analogy
that Bojanus ’ opinion can be probable in its essen-
tial point, — which is, that if the glands of Bojanus
are the analogues of the venous appendages of the
Cephalopoda, and of which I am persuaded with
Van der Hoeven (. Meckel's Arch. 1828, p. 502) is
the case, then they connect with the veins which
go to the branchiae, and not with the arteries which
go from the branchiae to the heart.

The blood-current in the glands of Bojanus ,
therefore, ought to pass towards the branchiae and
not towards the heart.

THE ACEPIIALA.

216

§ 198.

that of the parent, and the envelope of the mantle alone is common to
both.(l)

§ 198.

With the Acephala, the sexes are sometimes separate, sometimes united
in one individual. But the genital organs are very fully developed, and,
as with the Zoophytes, consist of an ovary and a testicle with an excretory
duct ; but in none are there copulatory organs, or uterine reservoirs for the

eggs-

The eggs are usually spherical, rarely pyriform or elliptical. The pale
yellow or reddish vitellus is finely granular, and surrounded with a vitel-
line membrane and a smooth colorless chorion.

The germinative vesicle has usually two nucleoli cemented together.
Often there is a layer of white substance interposed between the chorion
and the vitelline membrane. (1)

The sperm is milky, and, at the epoch of procreation, quite full of very
active spermatic particles. These always consist of an oblong, oval, or
pyriform body, to which is abruptly attached a delicate tail, whose motions
are not affected by the water in which these animals live.(2)

With the Acephala of separate sexes, the ovaries and testicles so closely
resemble each other, not only as to their form and the arrangement of
excretory ducts, but also as to their locality in the body, that they are
with difficulty distinguished each from the other, except at the period of
procreation.

The copulatory organs being absent, here, as with the Zoophytes, the
water is the fecundating medium.

1 This multiplication by buds has been observed
by Milne Edwards with Botryllus , PoLyclinum ,

Amaroucium, Didemnum , and Perophora. It
occurs also, undoubtedly, with other compound
Ascidiae, and is the cause of the increase of the
Ascidian-stock with the colonies of these animals.

With the simple Ascidiae — Clavelina lepadifor-
mis , and producta , the buds take the form of
suckers ( Stolones ), and the new individuals are
separated from their parents with the separation of
the mantle •, see Milne Edwards , Sur les Ascidies
composees, loc. cit. p. 41, PI. III. fig. 2°. ( Ama -
roucium prolifer um ), PI. VII. 1, lb. 1'. (Bo-
try llo ides rotifer a), and PI. II. fig. lc. 3 (Clav-
elina), Eysenhardt (Nov. Act. Acad. Lsop. Carol.

XI. p. 263, Tab. XXXVI. fig. 1, Ac.), has also ob-
served these stolons upon a simple Ascidian.

1 These eggs have been figured by Wagner , Pro-
dromus, &c., p. 7, Tab. I. fig 5 •, Carus , Erlauter-
ungstafeln, &c., lift. V. Taf. 1, fig. 2, and Nov. Act.

Acad. Leop. Carol, loc. cit. p. 26, Tab. I. (Ano-
donta and Unio), and by Milne Edwards, Sur les
Ascid. comp. p. 25, PI. IV. fig. 1-3 ( Amaroucium ).

2 The spermatic particles of the Acephala have
been described and figured by Wagner , in Wieg-
mann's Arch. 1835, II. p. 218, Taf. III. fig. 8
(Cyclas)} Siebold , in Muller's Arch. 1837, p.
381, Taf. XX. fig. 12-14 ( Unio , Anodonta , My-
tilus , Tichogonia , Cardium , Tellina, My a and
Cyclas)-, Kolliker , Beitrage, loc. cit. p. 37 (Pho-
tos), and Krohn , in Froriep's neue Not. No. 356,
p. 49, 52 (Phallusia and Salpa). Those of Ama-
roucium described by Milne Edwards (loc. cit. p.
21, PI. III. fig. lc.) differ from the usual type in
being fusiform and very long, — their tail not being
distinct from the body. Those of a Cynthia have
appeared to me of a similar fonn, — only the tail
was much longer and more delicate. With Phal-
lusia, on the contrary, I have distinctly seen them
with an oblong body to which is abruptly attached
the tail. The sperm of Polyclinum , Botryllus,
Didemnum , Diazona , and Phallusia , contains
spermatic particles of a Cercaria-fonn •, while those
of Salpa are filamentoid *, see Kolliker , Neue
schweiz. Denkschr. VIII. p. 43, fig. 30, 49, 53-57.*

* [ § 198, note 2.] The spermatic particles of
the Acephala throughout, are according to my own
observation, of a Cercaria-like form, — that is, hav-
ing a distinct head to which is attached a more or
less delicate tail. Their development, which I
have traced in many cases, is in special, daughter-
cells as with all other animals. They may, as
indeed they often do, assume various groupings
afterwards, but the real development appears sim-
ple and invariable. The shape of the head of the

particle I have found to differ widely, yet in each
case to present an uniformity of a zoological value.
Sometimes it is perfectly globular (Polyclinum),
sometimes oval (Unio, Anodonta ), sometimes ovo-
globular ( Ostrea ), sometimes oblong ( Ascidia ),
sometimes pyriform (Mytilus), sometimes conico-
pyriform (My a), and sometimes long-conical ( Cy -
prina). These forms may seem a refinement more
ideal than real, but the exact forms are determined
by micrometrical measurements. — Ed.

$ 199.

THE ACEPHALA.

217

§199.

The genital organs of Salpa are yet quite imperfectly known. They
cannot be found except at the procreative period, and in a very few species
only Ovaries have been discovered.

These consist of two flexuous zigzag cords, situated each side of the
median line of the back, between the mantle and peritoneum. Sometimes
they are prominent from their violet color.® The young are always
developed near the nucleus, in a cavity circumscribed by the peritoneum,
but it is yet not determined whether it communicates with the ovaries by
an oviduct, and whether it has distinct walls, so as to be comparable to an
uterus.

As to the Male genital organs, we are yet in almost complete want of
reliable researches.

From a single observation, it would appear that there is a testicle con-
cealed in the nucleus, between the coils of the intestine, and communicat-
ing, near the anus, with the cavity of the body.® But this still leaves it
uncertain whether these animals are hermaphrodites or of separate sexes.®

The Ascidiae are evidently hermaphrodites, for the male and female
organs, varying as to numbef and position, are found upon one and the
same individual between the walls of the muscular and branchial sacs.

With the compound forms, as well as with many of the simple ones, the
long, compact and usually yellowish ovarian mass is situated at the base
of the cavity of the body. From this there arises a large thin-walled ovi-
duct lined with ciliated epithelium, which ascends along the rectum towards
the anal tube and opens into the cloaca through a papilla. Along its side
and often beneath it, there is another long mass, which is evidently, from
its contents, a testicle. It has a narrow and very tortuous Vas deferens
filled with sperm, which runs parallel with the oviduct to its very extrem-
ity.® Cynthia presents a remarkable exception in this respect. The gen-

1 These two ovaries have been most thoroughly
observed with Salpa pinnata , see Forskul , Des-
crip. in itinere orient, observ. p. 13, Tab. XXXV.
B. bl, 4 5 Cuvier , loc. cit. p. 12, fig. 1. 2, *1' 5

Chamisso, loc. cit. p. 6, fig. 1 ; Del/e Chiaje , Me-
mor. &c. III. Tav. LXV. fig. 8, h. 5 Me yen , loc.
cit. p. 399, Tab. XXVII. fig. 1, 21, f. ; and the

Catal. of the Phys. Series, &c., I. PI. VI. fig. 1-4,

p. Cuvier (loc. cit. p. 22. fig. 8) has also^observed

two ovaries with Salpa cylindrica. It must also

be added here that, according to Forskul and Cha-

misso. there are two violet ovaries, with Salpa pin-

nata both in a simple and an aggregated form.

9 It was Krohn (loc. cit. p. 52) who recognized
with Salpa maxima a round testicle in the centre
of the nucleus. It was composed of numerous
seminiferous delicate canals filled with a white sem-
inal liquid, and opening by a short canal into the
natatory cavity. This testicle is probably the same
organ that Delle Chiaje (Descriz. &c. III. Tav.
LXXVIII. fig. 4, d.) has described as an ovary.
The assertion of Meyen , on the other hand (loc.
cit. p. 397, Tab. XXVIII. fig. 5-10), that a coni-
cal organ which, with Salpa mucronata , is situ-
ated in front of the cervical ganglion, belongs to
the male genital organs, is unfounded and cer-
tainly incorrect. But the observation of Krohn ,
on the contrary, gives support to the opinion
of Delle Chiaje (Mem. &c. III. p. 62, and De-
fccriz. &c. III. p. 42) that this white canal which,

19

with Salpa pinnata , lies along the intestinal canal,
is a Vas deferens.

3 At all events, the question needs careful exam-
ination, whether both the simple and the compound
forms of Salpa have male organs, or only one of
them. In this last case, these animals would have
some resemblance to the Aphides. Sars (loc. cit.
p. 77) having declared that the solitary individ-
uals of Salpa are sexless, then the aggregate indi-
viduals ought to be considered as representing the
perfect state of these animals ; but as yet neither
this author, nor Krohn ( Froriep's neue Notiz. XL.
p. 151, and Ann. d. Sc. Nat. 1846, VI. p. 110) have
been able to show the existence of ovaries in these
animals. At least these two naturalists pass in
silence the violet ovarian striae of Salpa , mentioned
by other observers.

4 Cuvier and Savigny have known, and often
figured the female organs of the Ascidiae. Those
of both sexes have been figured by Milne Edwards
(Observ. sur les Ascid. comp. p. 21, PI. III. fig. 1,
2l * * * * * * * 9. II. fig. 1, 3) with Clavelina , Amaroucium ,
and Polyclinum. The testicle of F/iullusia and
Rhopalaea is quite peculiar. It consists of a white
multiramose canal widely spread over the hepatic
layer of the intestinal canal *, while the ovary al-
ways lies in a loop of the intestine ■, see Delle Chi-
aje, Memor. III. p. 192, Tav. XLV. fig. 16, i.,and
Descriz. &c. III. p. 27, Tav. LXXXII. fig. 13,
LXXXIV. fig. 1, i. ( Fliallusia intestinalis and

218

THE ACEPHALA.

§ 199.

ital organs are situated upon both sides of the body between the branchial
membrane and the muscular wall with which they are intimately blended.
They form,, sometimes several round or angular projections divided into
two groups, and sometimes four long crests whose four distinct secretory
ducts open, after a short course, into the space included between the
branchial membrane and the muscular sac, at a variable distance from the
anal tube.®

With the Brachiopoda, ovaries only have as yet been found. These
surround the liver, and stretch upon both valves of the mantle around the
minute branches of the branchial vessels.®

With the Lamellibranchia, there are both hermaphrodites and separate
sexes. But the last are much the more common ; for the fh-st have as yet
been confined to Cyclas ,(7) Pecten ,® and Clavagella .(9) The testicles and
ovaries lie directly behind each other on each side of the body, between
the liver, intestine, and kidney. Their excretory ducts have not yet been
satisfactorily made out ; all that has been observed, is, that with Gyclas , the
eggs pass between the lamellae of the base of the external branchiae, and,

being here developed, produce sac-lik
With those species which are of
testicles are situated usually in the

mentula). The same arrangement has been ob-
served by Krohn (Froriep's neue. Not. No. 356, p.
49) with the testicle of Phallusia , and by Philippi
with that of a Rhopalaea ( Muller's Arch. 1843, p.
48, Taf. IV. fig. 9).

•5 Carus has distinguished, with acuteness, from
the ovarian group, as being a testicle, a collection
of projecting angular glands lying with Cynthia
microcosmus , upon the internal surface of the
muscular sac (. Meckel's Arch. II. 1816, p. 577,
Tab. II. fig. 1, 2, &c. — and, Nov. Act. Acad. loc.
cit. Tab. XXXVII. fig. 1, 2, k. k.). Savigny
also (loc. cit. p. 92, PI. VI. fig. 2, 3) has seen with
Cynthia microcosmus , and pantex , two glandu-
lar groups with their excretory ducts as the sexual
organs, but without determining that one of these
was a testicle ; while Cuvier (loc. cit. p. 28, PI. I.
fig. 3. d. d.) who has observed the testicular
group with Cynthia microcosmus , did not know
what to call it. According to Delle Chiaje (Me-
mor. &c. Tav. XLV. fig. 2, h. h.), the genitaj or-
gans of Phallusia phusa consist of numerous gland-
ular projections united into two groups, and hav-
ing two distinct excretory ducts. With Cynthia
canopus , the genital glands lie upon four long
crests, from the upper extremity of each of which
passes off an excretory duct towards the anal tube
( Savigny , Mem. loc. cit. p. 96, PI. VIII. fig. li,
2-). With Cynthia papillata , there are two of
these crests curved in a loop-like manner. ( Savig-
ny, loc. cit. p. 92, PI. VI. fig. 41, 42, or Delle
Chiaje , Memor. III. p. 191, Tav. XLVI. fig. 1, 1. 1.
and Descriz. &c. III. p. 27, Tav. LXXXII. fig. 11,
li h.). From the two extremities of each of these
p .sses off an excretory duct ; and in comparing
this arrangement with that of Cynthia canopus ,
it might be inferred that this loop-like disposition is
due to the fusion of two glandular crests. As to
winch of these crests are ovaries and which testi-
cles, it would appear from Krohn (. Froriep's neue
Not. No. 356, p. 50) that all are ovaries, for he has
observed, with a species perhaps identical with
Cynthia canopus , near the four oviducts, four other
excretory ducts not easily seen, and which, as Vasa
defer entia, arise from the ramified seminiferous
tubes spread out over the ovaries.

♦; For the ovaries of Terebratula and Orbicula,
see Owen , loc. cit. The figure of Muller (Zool.

:e swellings. (10)

separate sexes, (11) the two ovaries or
sub-hepatic region of the abdomen.

danica, I. p. 4, Tab. 5, fig 1, 7) of those of an Or-
bicula is very beautiful ; while that of Poll is not
as good (loc. cit. II. p. 191, Tab. XXX. fig. 19,
20).

7 For the hermaphroditism of this genus see my
memoir in Muller's Arch. 1837, p. 383.

8 According to Milne Edwards (Ann. d. Sc.
Nat. XVIII. 1842, p. 322, PI. X. fig. 1), with
Pecten glaber , the male gland is situated at the
upper, and the female gland at the lower part of
the abdomen. The two orifices found at the base
of the groove of the byssus belong to the testicles.
With another species of Pecten which I have ex-
amined, I was unable to confirm this hermaphro-
ditism, for I found in the abdomen only either
testicles or ovaries alone. Moreover the orifices
just alluded to, appear to me to belong to a gland
secreting the byssus ; see above § 179, note 4.

9 With Clavagella , Krohn found the testicles
beneath the liver, while the ovary surrounded it
and the stomach (Froriep's neue Not. No. 356,
p. 52).

19 These pouches, which, with Cyclas , contain
but a single egg, have been figured by Carus (Erl-
iiuterungstafeln, lift. III. p. 10, Taf. II. fig. 29. 3)
after Jacobson.

11 Leeuwenhoek (Contin. arcan. natur. detec.
Lugd. Batav. 1722, Epist. 95, p. 16) had already
distinguished male and female .individuals with
certain Lamellibranchia. Notwithstanding this,
he afterwards affirmed that all these Mollusks
were exclusively females, — an opinion still en-
tained by some naturalists (see Deshayes , in the
Cyclop. Anat. I. p. 700, and Garner, in the
Trans, of the Zool. Soc. II. p. 96). I had, however,
several years before, shown that the sexes were
separate with Unio , Anodonta , Mytilus , Ticlio-
gonia , Cardium , Tellina , and My a ( Muller's
Arch. 1837, p. 380). The fact has been con-
firmed by Milne Edwards (Ann. d. Sc. Nat.
XIII. 1840, p. 375) with Venus, by Owen
(Lectures, &c., p. 287) with Anomia, and by K al-
ii Jeer (Beitr&ge, loc. cit. p. 37) with Pholas. I can
also add to this list, Area, Pectunculus, and
Lithodomus. I have already mentioned (§ 196,
note 3) how Neuwyler , in taking the ciliary mo-
tions for those of spermatic particles, regarded the
kidneys of Anodonta and Unio as the testicles,

/

§ 200.

THE ACEPHALA.

219

They surround the coils of the intestine, and often ascend along the back,
covering the liver with their folds. Their excretory ducts are lined with
ciliated epithelium, and open each side of the bottom of the abdomen
through a fissure with smaller borders, communicating either with the cav-
ity of the mantle close by the renal opening, or with the renal sacs.(12) With
those species which have a very small abdomen, these organs are spread out
by numerous ramifications into the substance of both halves of the mantle. a3>

The two external branchiae serve, for the most part, the function of an
uterus ; for the eggs, having escaped from the oviduct, are lodged in their
compartments, and, by the aid of the cilia covering the cavity of the mantle,
receive the sperm which is introduced in the water for respiration. (U) The
quantity of eggs thus accumulated is so great, that with Anodonta these
organs are extraordinarily enlarged during the development of the young ;
and on this account the shells of the females of this genus are more convex
than those of the males. In this way the sexes of these Naiades can be
quickly distinguished from each other by the shell alone. (15)

§ 200.

Most of the Acephala undergo during their development, which always
begins by a complete segmentation of the vitellus, a metamorphosis which
is quite remarkable in many respects.

Among the Tunicata, the embryology of the Ascidiae is the best known.
An oval embryo follows upon the segmented vitellus, (1) and is quickly
changed into a Cercaria-like larva.® The tail is not formed from a grad-

and therefore considered the Naiades as hermaph-
rodites.*

12 The genital and urinary openings are contigu-
ous with the Naiades ; see above § 196, note 3, and
Neumann , De Anodontarum etUnionumoviductu.
Diss. llegiomont. 1827. This is the same also with
Tichogonia ; see Van Beneden Ann. d. Sc. Nat.
VII. 1837, p. 128. With Pinna nobilis , I have
found the genital orifice close behind those of the
renal sacs. According to Garner (loc. cit. p. 92),
a similar arrangement exists with Tcllina , Car-
dium , Mactra , Pfiolas , Mya, and Pecten. The
two genital orifices which Valenciennes (Arch,
du Mus. &c. I. PI. II. fig. 5) and JJelle Chiaje
(Descriz. &c. III. Tav. XC. fig. 2) have seen at the
lower end of the abdomen of Panopae a and Solen ,
belong probably also to the urinary system.

13 Mytilus ( Poli , loc. cit. II. p. 202, Tab. XXXI.
fig. 3), Anomia , Hiutella , JModiola , and Lithodo-
mus ( Garner , loc. cit. p. 97). With Lithodomus
dactytus , I have, however, always found the abdo-
men filled with testicular or ovarian masses.

H it is with the Naiades that the branchiae as
reservoirs of eggs, are best known ; see Poli , loc.
cit. I. p. 5, Tab. IX. fig. 18 ; Pfeiffer , loc. cit.
Abth. II. p. 11, Taf. II. fig. 16-18 ; Carus , Nov.
Act. Acad. &c. p. 17, Taf I. fig. 8 ; and Neu-
luyler , loc. cit. p. 18, Taf. III. fig. 14 ( Unio and
Anodonta). While remaining in the compart-
ments of the branchiae the eggs are slightly glued
together. With Unio , they often escape through

* [ § 199, note 11.] The hermaphrodite character
of the Naiades has recently been urged, and Rut-
land's marks of the different sexes by the shape of
the shell called in question 5 see article Zoology in
the Iconographic Encyclopaedia, edited by Spencer
F. Baird , p. 70. But see Rutland's criticism of

the anal fissures under the form of oval discs
shaped like the branchial compartments. For a long
time it was inexplicable how the eggs should al-
ways pass exclusively into the external branchiae,
when the cavities of the internal ones were so
much nearer the genital orifices. But Baer
( Meckel's Arch. 1830, p. 313) has shown that
their route is circuitous 5 they glide along the base
of the internal branchia to the cloaca, they then
ascend by a special canal of the mantle and pass
into the external branchiae. This course is the more
easily understood from the ciliated structure of
these organs. Will ( Froriep's neue Not. No. 620,
p. 57) affirms that with Tcllina the sperm of the
males is evacuated in an analogous manner through
the anal tube, and being there taken up by the
females through their respiratory tube is conducted
to the external branchiae.

I have also found embryos within the branchiae
of Teredo navalis.

15 At present, this difference in the convexity of
the valves appears to me to exist only with Ano-
donta ( Wiegmann's Arch. 1837, I. p. 415) ; but
Kirtland (Ibid. 1836, I. p. 236) has succeeded very
well in distinguishing, by this character, the males
and females of Unio, of North America.

1 The complete segmentation of the vitellus has
been observed by Milne Edwards (Sur les Asckl.
&c. p. 30, PI. IV. fig. 1-4) with the eggs of Ama-
roucium.

2 These Cercaria-like foetuses had already been

this article in the Proceed. Amer. Assoc. Advancem.
of Sc. 5th meeting, Cincinnati, 1851, p. 85. I have
examined this subject with some care by the micro-
scope, and have satisfied myself from an analysis
of the contents of the organs that the genera in
question are of separate sexes. — Ed.

220

TIIE ACEPIIALA.

§ 200.

ual elongation of the posterior part of the body of the embryo, but is pro-
duced by the fusion of a series of globules which result from the vitelline
segmentation. These globules lie upon the surface of the embryo and, in
their separation from it, assume a tail-like body which is folded in front,
and only latterly is extended out behind. With some of the compound
forms, it forms also two eye-specks upon the back of the larva.® At this
period of development the eggs are still in the cloaca, or perhaps have been
discharged through the anal tube. Subsequently, the embryos rupture
their shell, and then swim freely about by means of their very active
tails. Soon after this, the larvae are completely surrounded by a transpa-
rent structureless envelope, which ultimately becomes the mantle. They
are then fixed by their anterior extremity, — lose their tail and assume
their adult form.®

With the compound forms, before the larvae have become fixed and
deprived of their tails, numerous button-like prolongations arise from the
anterior extremity and extend into the mantle ; these, after the fixation of
the embryo, are changed into as many individuals.®

The development of the Salpae has yet been incompletely observed, for
its earlier conditions have received no attention. But the later ones pre-
sent very curious phenomena.

In the first place, it is quite remarkable that the two forms of these ani-
mals which are always viviparous, produce young wholly dissimilar. The
solitary individuals produce others joined together in a chain-like manner,®
while these last give rise again to the solitary forms. But in neither case
do the embryos undergo a metamorphosis. This chain of individuals is
usually composed of two rows joined together by several cords and envel-
oped in a common membranous tube. The individuals at the anterior
extremity of this tube are the more developed, — there being a gradation
in this respect to the posterior extremity, where they appear only as simple
punctiform bodies. This tube usually surrounds also the nucleus of the
parent, into the cavity of whose body its anterior extremity often widely

observed by Savigny (Mem. &c. PI. XI. fig. 23,
PI. XXI. fig. I1.) with Clavelina and Botryllus.

Subsequently they have been described by Au-
douin and Milne Edwards (Ann. d. Sc. Nat.
XV. 1828, p. 11) •, Sars , Beskrivelser, &c., p. 69,
PI. XII.), and Daly eU (Edinb. new Philos. Jour.
Jan. 1889, p. 158). Latterly Milne Edwards (Sur
les Ascidies, &c., loc. cit.) has furnished an exact
embryology of these Ascidians, but which has been
completed by Van Bene den (Mem. sur Pembryog.
l’anat. et la physiol, des Ascid. loc. cit.), and by
Kolliker (Ueber das Vorkommen tier Holzfaserim
Thierreicli loc. cit.).

[Additional note.] The memoirs cited above
have since been published, that of Van Beneden
in Mem. de PAcad. de Bruxell. XX. 1847, PI. II.
III.; that of Kolliker in Ann. d. Sc. Nat. V. 1846,
217, PI. VII.

8 Amaroucium and Aplidium , according to
Kolliker , and as confirmed by Van Beneden.

* [ § 200, note 5.] The embryology of the Ascidiae
has been followed out by Agassiz (Proceed. Amer.
Soc. for the Advancem. of Sc. 2d meeting, 1849,
Cambridge, p. 157), and by Krohn ( Muller's Arch.
1852, p. 312). The observations of Agassiz are
complete throughout, but unfortunately not yet all

4 For the development of a simple Ascidian, see
Daly ell , loc. cit.

5 According to Milne Edwards (loc. cit. p. 30),
these animals use these processes like suckers to fix
themselves. But this is contradicted by the obser-
vations of Kolliker , and Van Beneden.*

G This mode of propagation first described by Clia-
misso (loc. cit.), has been doubted by Eschricht ,
who thinks that the young Salpae produce solitary
foetuses, while those of a more advanced age pro-
duce the aggregated form. But, as Steenstrup (Le-
ber den Generationswechsel, p. 36), has justly ob-
served, there is no observation to support this view.

The alternate generation of the<S alpae, as first
described by Chamisso , has been confirmed in all
particulars by Sars , and Krohn (loc. cit.). It is how-
ever, singular that, according to Krohn , the single
egg of the aggregate Salpae is formed in an ovary,
while the whole development of these same animals
when solitary occurs from an internal gemmation.

published ; the published portion (loc. cit.) refers
more particularly to the formation and intimate
structure of the egg. Those of Krohn ure chiefly
confirmatory of those of Edwards and other ob-
servers above mentioned. — Ed.

$ 200.

THE ACEPHALA.

221

extends, while its opposite end appears attached near the nucleus to the
dorsal portion of the walls of the body.(,)

The solitary individuals, which are produced by the chain-like forms,
are also developed near the nucleus, and adhere quite singularly to the
dorsal wall of the parent by a peduncle resembling an umbilical cord.
These pedunculated embryos are always few in number, and have a proper
vitcllus. Often, however, there is only one.(l) * * * * * * (8) * * It may be questioned,
moreover, if these eggs are not gradually developed with their peduncle at
their place of incubation, or whether they become fixed at this place after
having been developed in, and separated from the ovary. At least, one
might almost think that, after all, this is only an internal gemmation.

With the Lamellibranchia, the Naiades particularly, are those whose
embryology has been observed. When the vitellus begins to segment, there
are two superficial contiguous vitelline cells that do not participate in this
process. ('J| These are gradually changed into two three-sided valves, while
the remaining portion of the vitellus is transformed into a round embryo
covered with cilia, which turns upon itself in the egg — being partly
enveloped by the valves. a0) This rotatory movement, however, soon
ceases, and the embryo divides itself into halves, each covered by a valve. (11)
Each of these valves has a ciliated mouth near the hinge, and a proper
intestinal canal. (12)

In the middle of the angle formed by these halves is raised a short, hol-
low cylinder, — the byssus-forming organ, and out of which- projects a very
long transparent bysstfk.<13)

(l) See the figures of Chamisso , loc. cit., of Quoy
anti Gaimard (Ann. d. Sc. Nat. X. 1825, p. 226,

1*1. VI LI. fig. 3-6, and Voyage de l’ Astrolabe loc.
cit.), of Delle Chiaje (Deseriz. &c. III. p. 42, Tav.
LXXVI. fig. 1), and especially those of Eschricht
(loc. cit. p. 35, Tab. I. II. IV. V.).

6b See Chamisso , loc. cit. fig. 1, D. 1, J. (Sal-
pa pinnata, with a very developed foetus), fig. 3,
F. (Salpa zonaria with three button-like foetuses
little developed), Quoy and Gaimard, Isis, 1836,
Taf. VI. fig. 12 (Salpa pinnata , with a very large
foetus), and Ann. d. Sc. Nat. loc. cit. PI. VIII.
fig. 7-0 (Salpa microstoma , with four button-
like foetuses); Meyen, loc. cit. p. 399, Tab.
XXVII. fig. 9-10 (Salpa pinnata ), Tab. XXVIII.
fig. 1, 2 (Salpa mucronata)) Tab. XXIX. fig. 1.
h. (Salpa antarctica ), fig. 2-4 (Salpa maxima),
Eschricht , loc. cit. p. 65. fig. 27, q. 36 (an individ-
ual from the ch£in of Salpa cordiformis contain-
ing five, isolated, pedunculated foetuses ; perhaps
here should be mentioned the five pedunculated
bodies which he (p. 39, fig. 18, p. 23) has de-
scribed and figured with Salpa zonaria ) ; finally

Delle Chiaje , Deseriz. &c. loc. cit. Tav. LXXVIII.
fig. 3 (Salpa maxima , with a pedunculated body),
and fig. 8, 13 (Salpa scutigera , with a developed
foetus).

9 These may be easily distinguished with Unio
and Anodonta , a clear nucleus in each segmented
division of the vitellus. Carus (Nov. Act. Acad,
p. 43, Tab. II. fig. 1, 3, 10, 11) has seen the vitel-
line cells nucleated, but he thought that the eggs,

which contained the faceted cells out of which are

ultimately formed the valves, were diseased and

dead.

10 This rotation of the embryo of mollusks had
already excited the astonishment of Leeuwenhoek
(Continuat. arcan. nat. Epist. 95). Its cause was

explained in a very unsatisfactory manner by

Home (Philos. Trans. 1827, pt. I. p. 39, or in Hen-

singer's Zeitsch. fur organische Physik. I. p. 394),

19*

and by Corns (loc. cit. p. 27), for they did not know
of the existence of cilia.

11 This division of the embryo with valves often
lying entirely open, has perhaps led RathkS
(Schrivter af Naturhist. Selsk. loc. cit. p. 166, Tab.
X. fig. 3), and Jacobson (Observ. sur le develop,
pretendu des oeufs des Moulettes ou Unio et des
Anodontcs dans leurs branohies, An. d. Sc. Nat.
XIV. 1828, p. 22, and De Blainville's report upon
this work) to regard the young of Naiades for
parasites, under the name of Glochidium parasiti -
cum. See also the works of Carus (loc. cit.), and
of Qu at ref ages (Sur la vie interbranchiale des
petites Anodontes, Ann. d. Sc. Nat. IV. 1S35, p. 283,
V. 1836, p. 321, PI. XII.).

Loven informs us that the young of Modiola ,
and Kellia are formed upon a wholly different
type. Their two valves, which are only slightly
separated, are overlapped by two lobes (as Man-
tle ?) which are everted and provided with very
active vibratile cilia ; the young swim by means
of these lobes (Arch, skandinav. Beitr. zur Natur-
gesch. Th. I. p. 155, Taf. I. fig. 9-11). I also have
observed with Teredo navalis , the embryos swim-
ming freely about by means of a foot-like organ
which protrudes between the valves and presents
an active ciliary movement.

12 Quatrefages , loc. cit. PI. XII. fig. 20.

13 Quatrefages (loc. cit.) has figured with
each embryo two byssus-organs out of which pro-
jects a double byssus. I have been unable to ob-
serve this, and, like Carus , have always found a
single byssus-organ with a single byssus.

It is quite remarkable that not only the Naiades,
but other Lamellibranchia also, have this byssus-
organ when quite young. Thus in the young of
Cyclas cornea , I have distinctly seen a hollow
pyriform glandular organ in the foot, and from
which projected a long simple byssus.

The embryos of Kellia have also a byssus ac-
cording to Loven (loc. cit.).

222 THE ACEPHALA. § 200.

Internally, the embryonic halves have three tentacular, stiff points, whose
bases are surrounded by collars/14’

Near the hinge a large muscle passes from one valve to the other ; this,
from convulsive contractions which occur from time to time, gradually
approximates the valves, which are wide open when the young individual
escapes from the egg. These valves are trigonal and slightly convex. One
of their sides goes to form the hinge, while the two remaining, which are
a little arched, unite at an angle opposite. With this angle is articulated
a prolongation curved downwards and inwards, and whose convex side has
several spines/15’ After their escape from the eggs, these embryos are held
together by their entangled byssuses. Subsequently, when the adductor
muscle has definitely closed the valves, the embryonic halves are blended
together, probably by a new metamorphosis.*

14 Cams, loc. cit. Tab. IV. fig. 14. 15 See Rathlci , Carus , and Quatrefages , loc. cit.

* [ End of § 200.] For the embryology of the 1848, p. 531, or in Wiegmann's Arch. 1849,
Acephala with almost a profuseness of detail, see p. 312). This observer has observed with care
Lovin (Ofversigt af Kongl. Vetenskaps-Acad. the formation of all the organs and their mu-
Forhandlingar, 5t0 Argangen, 1848, Stockholm, tual embryonic relations ; even the resume is too
1849, or its transl. into German in Muller's Arch, lengthy to be here quoted. — Ed.

BOOK TENTH.

CEPHALOPHORA.

CLASSIFICATION.

§201.

The organization of the animals composing this class is quite dissimilar;
and, as in the preceding class there were species which approached the
Zoophytes, so here there are those which are scarcely above the Worms.
Thus, it is a question whether the genus Sagetta, which is placed at the
head of this class, is really in its right place, although all the attempts to
place it in another group have furnished results no more satisfactory.

Then again, it may bo objected that the name Cephalophora should have
been given to a class composed of the Pteropoda, Heteropoda, and Gastero-
poda, since it belongs equally well to Cephalopoda ; but I have adopted it
for the sole reason of being unable to fin'd a better. (1)

The sub-order Apneusta with its two families Anangia and Angio-
phora, has been established by Kolliker in opposition to the other Gastero-
poda, which have distinct respiratory organs.® This division, composed
of small and very interesting species, is the more admissible since it is
based upon the anatomical structure of these animals ; and also as the
most recent investigations have shown that the term Phlebenterata used by
Quatrefages, is improper.

ORDER I. PTEROPODA.

Animals with natatory organs composed of wing-like or fin-like cutane-
ous lobes, symmetrically arranged upon the two sides of the body.

1 Meckel (Syst. der vergleich. Anat.) has al-
rt ady used this word in the same way.

- Kolliker has communicated to me a yet un-
published work in which he has described, beside
Flabellina and Polycera , three new genera of the
inferior Gasteropoda, under the names of Acan-
thi na, Lissosoma , and Rhodope

He has placed these, with those which Quatre-
fages has described under the name of Phleben-
terata , in the division of Apneusta which he
divides into two sections: 1. Angiophora, having

a heart and rudimentary vascular system. 2.
Anangia, without either heart or vessels.

224

TIIE CEPIIALOPIIORA.

$201.

Family : Sagittina.

Genus : Sagitta.

Family Hyaleacea.

Genera : Hyalea, Cleodora, Cymbulia , Tiedemannia, Cuvieria, Creseis ,

Limacina.

Family : Clioidea.

Genera : Clio, P neumodermnn, Spongiolranchaea.

ORDER II. HETEROPODA.

Animals whose locomotion is performed by a carinated natatory appara-
tus situated under the abdomen and provided often with a sucker.

Genera : PhyllirrhoU, Pterotrachca, Carinaria, Atlanta.

ORDER III. GASTEROPODA.

Animals which creep by means of a muscular disc situated under the
body.

SUB-ORDER I. APNEUSTA.

Without distinct respiratory organs, and without a shell.

Family : Anangia.

Genera : Rhodope, Pelta, Ac/aeon, Actaeonia, Lissosoma, Chalidis, Flabel-
lina, Zephyrina, Amphorina.

Family: Angiopiiora.

Genera : Tergipes, Venilia (Proctonotns), Calliopoea, Eolidina, Aeolis

(Eolidia).

SUB-ORDER II. HETEROBRANCHIA.

The branchiae inserted more or less freely upon various parts of the
body. Sometimes there is a very simple patelliform shell.

Family : Nudibranciiia.

Genera: Scyllaea, Tritonia, Thetis, Doris, Polycera, Plocamophorus.
Family : Infekobrancuia.

Genera : Diphyllidia, Phyllidia, Ancylws.

Family : Cyclobranciiia.

Genera : Patella, Chiton.

Family : Scutibranciiia.

Genera : Haliotis, Fissurella, Emarginula.

$ 201.

THE CEPHALOPHORA.

225

Family: Tectibranchia.

Genera : Gasteropteron, Umbrella , Boridium, Bulla, Bullaea, Aplysia,
Notarchus, Bolabella, Pleurobranchus, Pleurobranchaea.

SUB-ORDER III. TUBICOLAE.

Animals which are enclosed, together with their branchiae, in simple
slightly curved or irregularly flexuous tubes.

Family : Cirribrancuia.

Genus : Dentalium.

Family : Tubulibranciiia.

Genera : Vermetus, Magilus.

SUB-ORDER IV. PECTINIBRANCHIA.

Branchiae in a special cavity situated at the anterior part of the back.
Shell regularly spiral.

Family: Sigaretina.

Genus : Sigaretus.

Family : Purpurifera.

Genera : Buccinum, Harpa, Cassis, Purpura, Eburnea, Terebra.
Family : Canalifera.

Genera : Murex, Struthiolaria, Tritonium, TurbineUa , Fasciolaria.
Family: Alata.

Genera : Strombus, Rostellaria , Pterocera.

Family : Ceritiiiacea.

Genus : Cerithium.

Family: Volutacea.

Genera : Voluta, Oliva, Mitra.

4

Family : Involuta.

Genera : Cypraea, Ovula.

Family : Conoidea.

Genus: Conus.

Family: Trochoidea.

Genera : Scalaria, Turbo, Trochus, Phasianella, Rotella, Littorina, Jan-

thina.

Family : Neritacea. ;

Genera : Natica, Nerita.

226

THE CEPHALOPHORA.

$ 201.

Family : Potamopiiila.

Genera : Rissoa, Paludina, Ampullaria, Ceratodes, Valvata.

SUB-ORDER V. PULMONATA.

Family : Ampiiipneusta.

Genus : Onchidium.

Family : Lymnaeacea.

Genera : Lymnaeus, Plannrbis , Amphipeplea, Pkysa.
Family : IIelicina.

Genera : Helix, Caracolla, Succinea, Bulimus, Achatina, Clausilia.
Family : Limacina.

Genera : Lirnax, Arion , Testacella, Parmacella.

Family: Auriculacea.

Genus : Auricula.

Family : Operculata.

Genus : Cyclostoma.

BIBLIOGRAPHY.

Cuvier. Memoires pour servir a l’Histoire et a PAnatomie des Mollusques.
Paris 1817. A collection of monographs upon Clio, Hyalea, Pneurnoder-
mon, Tritonia, Doris, Scyllaea, Aeolis, Glaucus, Thetis, Phyllidia, Pleuro-
branchus, Aplysia, Bullaea, Bulla, Lirnax, Helix, Dolabella, Testacella,
Parmacella, Onchidium, Lymnaeus, Planorbis, Phasianella, Janthina,
Paludina, Turbo, Buccinum, Sigaretus, Haliotis, Fissurella, Emarginula,
Patella, Chiton, and Carinaria. Most of these appeared separately in the
Ann. du Museum d’Hist. Naturelle.

Mechel. Beitriige zur vergleichenden Anatomie. Bd. I. Hft. 1, 2,
Deutsches Archiv fiir die Physiologie, Bd. VIII. p. 190, and Archiv fur
die Anatomie und Physiologie, 1826, p. 13, containing anatomical details
upon Thetis, Doris, Diphyllidia, &c.

Wohnlich. Do Helice pomatia. Wirceburg, 1813.

Leue. De Pleurobranchaea. Diss. Halae, 1813.

Kosse. De Pteropodum ordine. Diss. Halae, 1813.

Feider. De Ilaliotidum structura. Diss. Halae, 1814.

Stiebel. Lymnaei stagnalis anatome. Diss. Gotting. 1815.

Deshayes. Anatomie du genre Dentale, in the Mem. de la Soc. d’Hist.
Nat. de Paris, II. 1825.

Rang. Observations sur le genre Atlante. Ibid. III. 1827, p. 372.
An Abstract of both treatises may be found in the Isis. 1832, p. 462, 471.

§ 201.

THE CEPHALOPHORA.

227

Treviranus. Ueber die Zeugungstheile und die Fortpflanzung der Mol-
lusken, und iiber die anatomischen Verwandtschaften des Ancylus fluviati-
lis, in his Zeitsch. fiir Physiologie. Bd. I. p. 1, and Bd. IV. p. 192.

Leiblein. Beitrag zu einer Anatomic des Murex brandaris, in Heusing-
er's Zeitschrift fur die organiscke Physik. Bd. I. p. 1, or Ann. d. Sc. Nat.
XIV. 1828, p. 177.

Quoy and Gaimard. Voyage de la corvette l’Astrolabe sous le com-
niandement de Dumont Durville. Zoologie, II. III. 1832 ; also in abstract
in Isis, 1834, p. 283, 1836, p. 31. Contains many observations on the
anatomy of the Cephalophora.

Rymer Jones. Cyclopaedia of Anatomy and Physiology, II. p. 377.
London, 1839. Art. Gasteropoda.

Eschrickt. Anatomische Untersuchungen iiber die Clione borealis.
Kopenhagen, 1838.

Van Beneden. Exercices zootomicjues, Faso. I. II. Bruxelles, 1839.
Monographs on Amphipeplea ( Dymnaeus glutinosus), Pneumodermon ,
Cymbulia, Tiedemannia, Hyalea, Cleodora, Cuvieria, and Limacina, ex-
tracted from the Nouv. Mem. de l’Acad. Royale de Bruxelles. That upon
P neumodermon is contained in Midler's Arch. 1838, p. 296.

Vogt. Bemerkungen iiber den Bau des Ancylus fluviatilis, in Muller's
Arch. 1841, p. 25.

Pouchet. Recherches sur l’Anatomie et la Physiologie des Mollusques.
Paris, 1842.

Quatrefages. Memoire sur l’Eolidine paradoxale, and Memoire sur les
Gasteropodes Phlebenteres, in the Ann. d. Sc. Nat. XIX. 1843, p. 274, I.
1844, p. 129.

Nordmann. Versuch einer Monographic des Tergipes Edwardsii. St.
Petersburg (1843), from the Mem de l’Acad. imperiale de St. Petersburg,
IV. ; abridged in the Ann. d. Sc. Nat. V. 1846, p. 109.

Krohn. Anatomisch-physiologische Beobachtungen fiber die Sagitta
bipunctata. Hamburg, 1844, also Ann. d. Sc. Nat. 111. 1845, p. 102, and
Annals of Nat. Hist. XVI. 1815, p. 289.

Hancock and Embleton. On the Anatomy of Eolis, in the Annals of
Nat. Hist. XV. 1845, p. 1.

Allman. On the Anatomy of Actaeon. Ibid. XVI. 1845, p. 145.

ADDITIONAL BIBLIOGRAPHY.

Rymer Jones. Cyclopaedia of Anatomy and Physiology. Art. Ptero-
poda , IV. p. 170.

Wilm. Observationes de Sagitta mare germanieum circa insulam Hel-
goland incolente. Berol. 1846. [Refers especially to the sexual and ner-
vous systems.]

Middendnrff. Beitriige zu einer Malacozoologia Rossica. St. Peters-
bourg, 1847 (from the Mem. Sciences Nat. Tom. VI.).

Mollusken, from the author’s Sibirischer Riese II. Th. I. St.

Petersbourg, 1851. [These works although chiefly zoological contain many
anatomical details.]

Milne Edwards. Observations sur la circulation chez les Mollusques
(Patella. Haliotis^Aplysia, Thetis, Limax , Triton), in the Ann. d. Sc. Nat.
VIII. 1847, p. 37.

Blanchard. Recherches sur l’organisation des Mollusques Gasteropodes

228

THE CEPIIALOPHORA.

$ 202.

de l’ordre des Opisthobranches (Milne Edwards), Tectibrancbes, Nudi-
brancbes, Inferobranches (Cuvier) ; Ann. d. Sc. Nat. IX. 1848, p. 172, XI.
1849, p. 74.

Alder and Hancock. A Monograph of the British Nudibranchiate Mol-
lusca with figures of all the species. Part I. 1844. Part Y. 1851. Un-
finished. [This fine work contains very valuable anatomical details and
includes Hancock's contributions upon these animals given also in the Ann.
of Nat. Hist.]

On the Anatomy of Qithonia, in the Ann. of Nat. Hist. IX.

1852, p. 188.

Hancock and Embleton. On the Anatomy of Eolis (Contin.). Ann.
Nat, Hist. 1848, I. p. 105, also 1849, III. p. 183.

Hancock. On the olfactory apparatus of theBullidae. Ibid. IX. 1852,

p. 188.

On the Anatomy of Doris, in the Philos. Trans. 1852, Part-

II. p. 1.

Souleyet. Memoire sur le genre Acteon d’Oken, Journal de Concholo-
gie, 1850, No. I. p. 1.

Leidy. The Terrestrial air-breathing Mollusks of the United States, &c.
Described and illustrated by Amos Binney. Edited by Aug. A. Gould,
M.D. 2 vol. Boston, 1851. Special Anatomy by Joseph Leidy, M.D.
[For beauty of execution Leidy's drawings are unsurpassed.]

Leydig. Ueber Paludina vivipara : im Beitrag sur naheren Kenntniss
dieses Thieres in embryologischer, anatomischer und histologischer Bezie-
hung; in Siebold and Kolliker's Zeitsch. II. 1850, p. 125.

Anatomische Bemerkungeu fiber Carinaria, Firola und Amphi-

cora. Ibid. III. 1852, p. 325.

Koren and Damelssen. Bitrag til Pectinibranchiernes Udviklingshisto-
rie, Bergen, 1851, or its Transl. into the French, in the Ann. d. Sc. Nat.
XVIII. 1852, p. 257.

Gegenbaur. Beitrage zur Entwickelungsgeschichte der Landgastropo-
den, in Siebold and Kolliker's Zeitsch. III. 1852, p. 371.

Bau der Heteropoden und Pteropoden. Ibid. IY. 1853, p.

334.

Moquin-Tandcm. Histoire naturelle des Mollusques terrestres et fluvi-
atiles de la France, 1847, avec un Atlas de 25 Planches, &c. Anatomie
de Ancyle fluviatile, in the Jour, de Conchol. 1852, No. I. p. 7, No. II. p.
121, and No. IV. p. 337.

Rang and Souleyet. Histoire naturelle des Pteropodes, Paris, 1852.

CHAPTER I.

CUTANEOUS SYSTEM.

§ 202.

The cutaneous envelope of the Cephalophora consists of a dense dermis,
of a cellular structure, often containing pigment matter which is free
or in cells. It is covered with a delicate ciliated epithelium, which, with

TIIE CEPHALOPnORA.

229

§ 203.

the aquatic species, is extended over nearly the whole body, but with
those which are terrestrial, is confined to certain spots.® With the Gas-
teropoda, its external surface is striated or tuberculated ; on the whole, the
skin of these animals closely resembles a mucous membrane and secretes
constantly a large quantity of mucus.

It has an extraordinary contractility, due to a muscular layer intimately
blended in its texture.

With many species, the skin forms around the neck or back a fold, which
is usually circular ; the posterior or the upper part of this fold is dilated
into a hernial sack containing a portion of the viscera. This portion of
the skin is called the mantle. & With many, it can be wholly withdrawn
into the body, and then the orifice of the fold acts as a sphincter.®

§ 203.

Very many of the Cephalophora carry upon their back a univalve shelf1 2 *'
which is formed by the border and external surface of the mantle, and, in a
few cases only, in its interior.®

The border of the mantle is the tissue most concerned in the formation
of the shell. The shell’s increase depends upon it, and for this purpose
it is always in contact with the orifice.

With the majority of the terrestrial Gasteropoda <3) the completed shell has
a lip at its orifice, 'which, in some aquatic species/4 *' is repeated several times
at regular intervals during the development. In many Pectinibranchia,
the border of the mantle has prolongations, which also secrete lime and pro-
duce around the orifice of the shell wing-like or spinous processes.® With
many species of this sub-order, one of these processes has a kind of canal,
called the Siphon, which conducts the water into the respiratory cavity.
With some, this siphon is contained in an appendix to the orifice of the
shell/6’ while, with others, it is protruded through a fissural opening of this
last. (7)

With some Gasteropoda, the mantle is folded over a large portion of the
external surface of the shell, which it covers with a calcareous substance.®

The borders of the mantle have numerous, short, glandular follicles, whose
walls are composed of large cells, some of which contain a finely-granular

1 Ciliated epithelium covers the entire surface of
the body with Lymnaeus , Planorbis , Pluysa,
Paludina , Valvata, Tcrgipcs , Flabellina , and
Polycera. With the terrestrial Gasteropoda, I
have found it only on the surface of the foot, and
with Arion , upon also the borders of this organ,
which is separated from the rest of the body by a
longitudinal furrow. I cannot, therefore, support
the assertion of Valentin {Wagner's Handwort
erbuch der Physiol. I. p. 429) that with Helix and
Lirnax , the whole surface of the body and even the
tentacles are covered with this epithelium.

2 With Limax , Arion , and some allied genera,
tills mantle is quite rudimentary, — covering like a
shield only a small portion of the back.

•3 The genus Sagitta differs, in this respect, from
all the other Cephalophora. Its skin is without
folds, forms a kind of cylinder, and consists of a
dense dermis perfectly smooth and non-contractile.

At first, its structure appears to be homogeneous,
but a more careful examination shows extremely
delicate parallel fibres running from before back-

wards in uninterrupted and apparently varicose

rows ; they resemble nuclear fibres [of Henle).

20

1 With Chiton , exceptionally, the shell is
formed of several imbricated pieces so united as to
be movable. In some species the organic so much
exceeds the calcareous substance, that the shell
has a horny aspect, as with Aplysia , Hyalea ,
and Cleodora. With Cymbulia , the shell is even
cartilaginous ; that of Cypraea , on the contrary, is
composed almost exclusively of lime, — the quan-
tity of organic substance being very small.

2 With Bullaea , Limax , and Testacella, the
shell is wholly concealed in the mantle. With
Arion , the lime secreted in the interior does not
unite with the shell, but forms a mass of loosely
juxtaposited granulations.

3 With the Auriculacea, and many of the Heli-
cina.

4 Murex , Harpa , Scalaria.

5 Strombus , Pterocera , Murex.

G Cerit hium, Murex, Rostellarict, Turbinella ,
Fasciolaria.

I Harpa , Oliva , Voluta, Buccinum , Do Hum,
Conus.

8 Ovula , Cypraea.

230

THE CEPHALOPHORA.

§ 203.

substance (carbonate of lime) wbicb effervesces with acids,® while the oth-
ers enclose pigment granules. <10) Calcareous cells are also found, but
fewer, in the parts of the mantle covered bj the shell. These portions of the
mantle serve to increase the thickness of the shell, and to repair the loss
of substance in places removed from the mantle-borders.

The intimate structure of the shells of these'animals is much simpler than
that of the Acephala. They are homogeneous throughout, and correspond to
the internal layer of the Bivalvia. When the carbonate of lime has been
extracted, the remaining organic base consists of a homogeneous membrane
having numerous folds varying very much as to form and number, accord-
ing to the genera.

This organic base is produced by the external surface and border of
the mantle, in the form of a mucous liquid containing calcareous and pig-
ment granules, and which, hardening, forms the successive layers of the
shell. ffl)

Usually there is no epidermis connecting the border of the mantle with
the orifice of the shell ; it can, therefore, together with the body of the
animal, be drawn deeply into the shell. With some Gasteropoda, how-
ever, the shell is covered with a kind of epidermis, which has even hair-
like processes. <la

Many of this same order have, upon the posterior dorsal surface of the
foot, a peculiar plate, by which they can tightly close the opening of their
shell after having withdrawn their bodies.

This plate, or operculum, composed, sometimes of concentric rings,
and sometimes of lines spirally rolled together in the same plane, is
composed of a calcareous, or a horny substance. (13) In both cases its organic
base is lamellated or plicated like that of the shell. The operculum ( Oper-
culum caducum ) with which certain Helicina close their shell at the begin-
ning of winter, is completely structureless, and without rings, spiral lines
or lamellae.

Beside these external calcareous products, there are certain species of
these animals, which have other deposits of the same nature inside the skin
and in various parts of the body, which, in the form of needles, form super-
posed, reticulated masses. (14)

9 See //. Meckel , Ueber die KalkdrCisen der
Gartenschnecke, in Muller's Arch. 1846, p. 17.

10 According to Gray (Lond. Med. Gaz. pt. V.
1837, 38, vol. I. p. 830), some Gasteropoda have, in
the border of their mantle, numerous glands which
secrete pigment matter ; and the shell will be
marked according as this secretion is continuous or
irregular.

11 The only solid particles I have been able to
find in this mucus are calcareous molecules which
disengage gas when dissolved in acids.

In the shells of Helix, Bulimus , Cyclostoma ,
Paludina, Neretina , and Cypraea, I have also
been unable to find the cellular structure which
Bowerbank (Ann. of Nat. Hist. No. 68, 1843) af-
firms exist in those of several Gasteropoda.

12 Helix hirsuta , hispida, villosa , and the
young of Paludina vivipara.

13 The operculum is horny with Paludina, Co-
nus, Buccinum, Cassis, Mur ex ; and calcareous
with Nerita , Turbo , Cyclostoma.

14 With Paludina vivipara, there are, between
the cutaneous layers, numerous globular calcareous
bodies formed of concentric lamellae ; and with
Limax , not only is there a calcareous plate in the
mantle, but also a powder of the same nature scat-
tered here and there in other parts of the skin.
The white striae which adorn the sides of the neck
and foot of Helix are composed of short, cylindri-
cal, thickly-set calcareous needles.

According to Kblliker , the entire skin of Poly-
cera is crowded with analogous, but ramified
needles.

Similar, probably, are the concretions which,
with Tergipes, are found everywhere beneath the
skin ( Nordmann , loc. cit. p. 9, Taf. III. fig. 4 a.),
and the calcareous net-work found in the mantle
and foot of several species of Doris ( Lovin , Isis,
1842, p. 361, Taf. I. fig. 3).

§ 204.

THE CEPnALOPHORA.

231

CHAPTER II.

MUSCULAR SYSTEM AND ORGANS OF LOCOMOTION.

§ 204.

The muscles of the Cephalophora are composed of smooth, primitive
bundles, which are easily separated into short oblong fragments, and often
have numerous nuclei scattered through their substance.*

The cutaneous muscular system is highly developed ; it consists of a
muscular layer made up of oblique, longitudinal and transverse fibres,
which are not divisible into separate muscles, and are intimately united
with the skin.(1> Upon the ventral surface, with the Gasteropoda, this
cutaneous layer is very thick and forms a long disc, — the foot. The fibres
of this foot, by contraction, produce wrinkles which succeed each other
from behind forwards in a wave-like manner ; by this means the whole
foot glides easily over solid bodies or on the surface of the water.® Many
Gasteropoda use their foot for a sucker also, and then there are circular,
tendinous fibres inwoven between those of the muscle proper. <3)

With the Heteropoda, there is, upon the ventral surface, a laterally com-
pressed process which has numerous muscular fibres. These animals swim
upon their back and use this as an organ of locomotion ; while a sucker,
situated upon its borders, is used, it is said, as an organ for attachment.®
The Pteropoda, Thetis , and Aplysia, have, upon certain places of their body,
wing-like expansions, which are traversed by numerous muscular fibres,
and are used as oars for swimming.® The horizontal fins which are found

1 Here again the genus Sagitta forms an excep-
tion. Its muscular fibres are distinctly striated,
and its whole muscular system consists of a simple
cutaneous layer composed only of longitudinal
fibres.

V The breadth of this foot varies much according
to the species. With Scyllaea , and Tritonia , it
forms only a very narrow furrow, with which these
animals can embrace marine algae.

3 Thus, with Patella and Haliotis.

4 See Forskdl , leones, &c., Tab. XXXIY. fig. A.j
Delle Chiaje , Memor. loc. cit. Tav. XLI. fig. 1,
and Descriz. loc. cit. Tav. LXIII.-IY. 5 Quoy and
Gaimard , in the Ann. d. Sc. Nat. XYI. 1829, PI.
II. fig. 4-6, or in Isis, 1833, Taf. YI. ( Pterotra -
chea and Carinaria ) ,• and Rang , in Mem. de la
Soc. d’Hist. Nat. de Paris, loc. cit. p. 375, PI. IX.
fig. 1, 10, a. d. (Atlanta).

5 See Eschricht , loc. cit. Tab. I. fig. 5 (Clio)
and Van Beneden , Exercises, &c., Ease. II. PI. I.
II. (Cymbulia and Tiedemannia). It is possible
that Thetis uses as natatory organs, beside its
large cephalic fin, the contractile appendages
which exist on each side of the back. These last

* [ § 204.] For histological studies on the muscu-
lar tissue of the Cephalophora, see Lebert and
Robin (Muller's Arch, 1846, p. 129) and Leydig
loc. cit. (Siebold and Kbllilcer's Zeitsch. II. 1850,
p. 191). According to the first-mentioned observers,
the intimate composition of this tissue with species
they examined (Mytilus edulis , Buccinatum
tin datum , and Pec ten), is very delicate primitive
fibrillae which are either smooth and uniform, or

have had various interpretations as to their na-
ture, from the ease with which they are detached
(see Meckel in his programme ; Additamenta ad
historian! Molluscorum, Pisciuin et Amphibiorum.
Halae, 1832).

Rudolphi (Synop. Entoz. p. 573), and Otto
(Nov. Act. Nat. Cur. XI. p. 294, Tab. XLI. fig. 1,
a-f.) have taken them for parasites under the
names of Phocnicurus varius , and Vertumnu.s
thetidicola.

Delle Chiaje , who formerly described them
under the name of Planar ia ocellata , has since
concurred in the opinion of the last two natunalists;
but he suggests that they may be the young of The-
tis attached to the back of their parents to obtain
nourishment 5 see his Memor. loc. cit. I. p. 59, Tav.
II. fig. 9-15, II. p. 265, III. p. 141, Tav. XXXIX.
fig. 1, and his Descriz. &c. II. p. 37. Although the
real nature of these appendages was made known
long ago by Macri (Atti della reale academia delle
scienze di Napoli. II. 1778, p. 170, Tav. IV.), yet it
is only recently that it has been confirmed by Ve-
rani (Isis, 1842, p. 252) and Krohn (Muller's' Arch.
1842, p. 418).

are finely punctated through their whole length.
With Paludina , Helix , Bulimus , Carocolla ,
Leydig found the essential element of this tissue
to consist of a tube, formed by the fusion of cells
linearly arranged j the nuclei of these cells were
often visible.

My own observations on Natica heros agree
with those of Leydig — that the essential structure
is a fibre and not a fibrilla. — Ed.

232

THE CEPHALOPHOKA.

§§ 205, 206.

upon various points of the body of Sagitta, differ from the locomotive
organs of the other Pteropoda in being composed wholly of parallel, homo-
geneous fibres, which decrease in size from the base to the border of this
organ, but which have not the least resemblance to those of muscle.®

Some Pteropoda have tentacle-like processes situated in bundles about
the mouth, which have a small sucker at their end ; they are, therefore,
probably used as organs of attachment.6 (7) 8

§ 205.

Beside this cutaneous muscular system, the cavity of the body contains
isolated muscles which serve different uses. With the turbinated Gastero-
poda, a large muscle arises from the columella, and, after dividing into
many parts, is spread over the sides of the body to be inserted into the foot,
and serves as its retractor. Several other muscles of variable size arise
also from the columella, and are distributed, some to the tentacles, and
others to the pharynx and the penis — serving also as retractors of these
organs. With the shell-less Cephalophora, the retractors of these various
organs arise from the inner surface of the mantle, or from the foot.(1>

CHAPTER III.

NERVOUS SYSTEM.

§ 206.

The central part of the nervous system of the Cephalophora consists of a
group of closely approximated ganglia, connected together by several nerv-
ous filaments, and which surrounds, like a ring, the base of the pharynx or
the oesophagus. This oesophageal ring may be divided into several por-
tions ; one situated above, one below, and one each side of the oesophagus.
The portion lying above consists usually of two very large contiguous
ganglia, which may be called the brain, since they furnish nerves to most of
the organs of sense, — that is, the tactile organs, the eyes, and sometimes
also the organs of hearing.

The portion lying below, varies much in its form and size. It consists,
sometimes of a group of ganglia blended together, or circularly united by
short connecting filaments, and sometimes of a simple transverse cord.
The two lateral portions consist always of two cords connecting the upper
and lower parts just mentioned. The lower portion, which sends nerves
principally to the muscles of the foot and to several viscera, is often asym-
metrical. The peripheric nerves are always given off from the ganglia
and never from the connecting cords, of the oesophageal ring.

6 See Krohn , cit. p. 6.

7 See Cuvier , > in. loc. cit. p. 8, PI. 1. B. fig.

8 ( Pneumoden/i ) ; D'Orbig'ny, Yoy. dans
1’Amer. merid., or i-is, 1839, p. 497, Taf. I. fig.
IX. 1-15 ( Spongiouranchaea and Pneumoder-

mon ), and Eschricht , loc. cit. p. 8, Tab. II. fig.
12, 13 ( Clio ).

1 For these isolated muscles, see Cuvier , Mem.
sur la limace et colima^on, loc. cit. p. 11, PI. IL
fig. 2, 3.

§§ 207, 208.

THE CEPHALOPHORA.

238

§ 207.

The nervous system of the Cephalophora is enveloped by a very distinct
fibrous neurolemma containing often various pigments, which, in some
species, give it, and especially the ganglia, a well-marked color. (,) The
neurolemma enters the ganglia and forms there numerous septa which
separate the ganglionic globules into groups. These are very distinct,
and although of variable size, always contain a very large nucleus
composed of obscure granules in the midst of which are seen usually two
to four transparent nucleoli of unequal size.®

These ganglionic globules are very often pedunculated,® and then their
very slender peduncles or processes usually extend far into the nerves
which are given off from the ganglion, thus leading one to infer that these
globules are the origin or termination of the nervous fibres.® Moreover,
these primitive fibres which traverse the ganglia, are always situated in
that portion of them which is contiguous to the oesophagus or pharynx,
while the opposite portion is occupied by the ganglionic globules.

§ 208.

There is a great variety in the form and arrangement of the different
parts of the nervous centre, according to the' orders and families, as fol-
lows.®

1. The Heteropoda quite resemble the Lamellibranchia by their
widely-separated ganglia connected by very long commissures. At the
anterior extremity of their body, and above the oesophagus, there is a
cerebral mass which sends backwards two long nervous cords, which, after
passing along each side of the intestinal canal, terminate by entering the
inferior ganglionic portion ( Ganglion peddle ), situated near the ventral
surface. The cerebral portion furnishes nerves to the organs of sense, to
the skin, and to the lips, while the posterior portion sends them chiefly to
the foot, and to the muscles of the tail.®

1 These ganglia are orange-colored with Lym-
naeu$ and red with Planorbis , Paludina , Hya-
lea , Pleurobranchus.

2 Hannover (Recherch. microscop, sur le Sys-
t£me nerveux, 1844, p. 69, PI. VIII. ) has very well
described and figured the ganglion-globules of
Helix and Limax.

3 Judging from Ehrenberg's figure (Uner-
kannt. Struktur &c. Tab. VI. fig. I. I2.) of the
pedunculated ganglion-globules of Arion empiri-
corum , he was not aware of the large nuclei which
they contained.

* [ § 207, note 4.] Leidifs results, after very
careful dissection, do not accord with these, for he
observed none of the nerve-fibres originate or ter-
minate in the ganglionary globules ; see loc. cit.
vol. I. p. 243. — Ed.

t [ § 208, note 1.] See also Alder and Hancock ,
loc. cit. Part. II. PI. II. fig. 9 ( Dendronotus ), PI.
IV. fig. 16 ( Doto ); Part. III. PI. VIII. fig. 8
(Eolis); Part. IV. PI. V. fig. 1, k. (Scyllaea) ;
Part V. PI. II. fig. 13 (Doris), PI. XLIII. fig. 10
(Anliopa) ; then Lcydig , Ueber Paludina vivi-
20*

4 See Helmholtz , De fabr. Syst. nerv. evert, loc.
cit. p. 10 5 Hannover , loc. cit. and Will , in Mul-
ler's Arch. 1844, p. 76.*

1 For the descriptions and figures of the nervous
system of several Cephalophora, see Cuvier , Mein,
loc. cit. ; Garner , Trans, of the Linn. Soc. XVI L.
p. 488 •, Rymer Jones , Cyclop, of Anat. p. 392,
Art. Gasteropoda ; Anderson, Ibid. III. p. 605,
Art. Nervous System ; and Pan Beneden , Exer-
cises zoot. loc. cit.f

2 See Milne Edwards , Ann. d. Sc. Nat. XV III.
1842, p. 326, PI. XI., and Delle Chiaje , Descriz. II.

para, &c., loc. cit. p. 152, Taf. XIII. fig. 49, a. fi.
(Paludina)-, Blanchard , Ann. d. Sc. Nat. XI.
1849, p. 78, PI. III. fig. 1, PI. IV. fig. 1 (Janus) ;
Middendorjf', loc. cit. p. 75, Taf. I X. (Chiton) ;
Leidy , loc. cit. PI. I. fig. I. 11-14 (Limax), PI.
IV. fig. V. 15-17 ( Vaginulus ), PI. V. fig. I. 32, 33,
34 (Bulimus), PI. VI. fig. II. 25, PI. VII. fig.
VIII. 20, PI. IX. fig. IV. 26, 27, PI. X. fig. IV.
24, 25, 26 (Helix)-, PI. XIII. fig. IV. (Helicina),
PI. XIV. fig. IV. PI. XVI. (Glandina). — Ed.

234

THE CEPHALOPIIORA.

§ 208.

The nervous centre of the genus Sagitta is in many respects like that
of the Heteropoda. A hexagonal cerebral ganglion lies upon the upper
surface of the oesophagus-; another quite large is situated in the centre of
the ventral surface of the trunk. These intercommunicate by two large,
very long cords. The cerebral ganglion gives off two pairs of nerves;
— of these the anterior are distributed to the base of the oral hooks, and
the posterior to the organs of vision ; each sends, internally, a filament
which passes backwards and joins at the middle of the posterior part of the
head with the one from the opposite side, thus forming a loop. The ven-
tral ganglion sends off backwards two considerable, diverging nerves, from
whose external surface pass off numerous, delicate, cutaneous filaments.®

2. With some Tectibranchia, a simple cerebral ganglion above, and
two others, quite widely separated, below, are, all three, connected together
by as many cords, thus forming a large oesophageal ring.®

3. With many Pteropoda the cerebral ganglia are wanting, while the
lower portion is highly developed. This last is composed of two or three
pairs of ganglia blended together, and from which passes off a simple
commissure embracing the oesophagus.®

4. With very many of the Apneusta and Nudibranchia, as also with
several other Heterobranchia, the cerebral mass is highly developed,
while the remaining part of the oesophageal ring consists of a simple nerv-
ous cord. The two or four cerebral ganglia are either connected by trans-
verse commissures, or intimately blended together.®

p. 99, Tav. LXm. ( Carinaria ). Plerotrachea
has a similar disposition. According to Delle
Chiaje (loc. cit. Tav. LXIII. fig. 14, Tav. LXIV.
fig-. 11), a short commissure arising from the cere-
bral ganglionic mass, embraces, in a ring-like man-
ner, the oesophagus of Carinaria and Pterotra-
chea ; but this is not mentioned by either Cuvier ,
or Milne Edwards.

3 See Krohn , loc. cit. p. 12, fig. 2, 5, 13.*

4 With Aplysia , according to Cuvier , Mem. loc.
cit. p. 22, PI. III. IV., and with Pleurobranchus ,
according to Delle Chiaje , Memor. loc. cit. Tav.
XLI. tig. 8, o. v. v. I have found the oesophageal
ring arranged in the same way with Pleuro-
branchaea.

o This form is found especially in those species
where the eyes and tentacles are abortive or en-
tirely wanting ; see Van Beneden , Exercices zoot.
Fasc. II. ( Hyalea , T iedemannia, Cleodora , Cu-
vieria , Limacina , and Cymbulia). Probably to
the absence of these organs is due, with the Ptero-
poda, the often confounding of the dorsal with the
ventral surface. It is, moreover, interesting that,
among the Gasteropoda, Chiton , which is without

* [ § 208, note 3.J For the cutaneous nerves
and their mode of distribution with Carinaria ,
see Leydig ( Siebold and Kdlliker's Zeitsch. III.
1851, p. 325). Here, the nerves branch into finer
and finer filaments, and finally lose themselves in
a terminal net-work 5 these terminal branches have
frequent ganglionic corpuscles in their course.
These corpuscles appear to be developed in the
nerve-tube *, see loc. cit. Taf. IX. fig. 5. — Ed.

t (§ 208, note 5.J Middendorff (loc. cit. p. 75)
has described with Chiton a flat and almost per-
pendicular nervous band situated on the internal
sphincter of the mouth, and which he thinks is
probably two ganglia cerebralia fused together
(Taf. IX. fig. 6, a) ; this band sends off numerous

eyes and tentacles, has a transversal row of six
sub-oesophageal ganglia, but no cerebral ganglia j
see Cuvier , Garner , and Rymer Jones , loc. cit.

For the nervous system of the Pteropoda, see
also Souleyet , Comp. rend. XVII. No. 14 5 or
Froriep's neue Not. XXVIII. p. 84. t

G With Bullaea , Doridium , and Phyllidia ,
there are two cerebral ganglia united by a more or
less long commissure 5 while with Tritonia , and
Scyllaea , there are four united by short commis-
sures ; see Cuvier , loc. cit. With Aeolis , the
cerebral mass is also composed of four ganglia
transversely arranged ( Delle Chiaje , Descriz.
loc. cit. Tav. LXXXVIII. fig. 12, 15, and Han-
cock and Embleton , loc. cit. PI. V. fig. 16). With
Eolidina , Zephyrina , Amphorina , Pelta , and
Chalidis , there are two pairs of fused ganglia
which are connected together by a delicate com-
missure ( Quatrefages , Ann. d. Sc. Nat. XIX.
1843, p. 293, PI. XI. fig. 3, 4, I. 1844, PI. VI. fig.
1-4). With Thetis , and Doris , on the other
hand, the brain is a single mass, of considerable
size, and situated in the neck ( Cuvier , loc. cit.).J

Nervi labiates to borders of the mouth (Taf. IX.
fig. 6, ft). — Ed.

J [ § 208, note 6.] Blanchard (Ann. d. Sc. Nat.
XI. 1849, p. 78) describes the central nervous sys-
tem of Janus ( Eolidia ) as consisting of six med-
ullary masses around the oesophagus, — the cere-
bral, the cervical and the pedal ganglia 5 see his
figures, PI. III. fig. 1, and PI. IV. fig. 1. For the
Cephalic nervous system of the Nudibranchia, see
Alder and Hancock , loc. cit. Part II. PI. II. fig.
9 ( Dendronotus , Doto ), cerebral ganglia, four,
and give off ten pairs of nerves ; Part III. PI.
VIII. fig. 3 ( Eolis ), cerebral ganglia, four, and
give off twelve pairs of nerves •, Part IV. PI. V. fig.
13 ( Eumenis ), cerebral ganglia, four, and give

§ 209.

THE CEPHALOPIIORA.

235

5. With other Apneusta, the oesophageal ring is composed of several
contiguous ganglia which closely bind the oesophagus, but have no appar-
ent commissures. (7)

6. The other Gasteropoda, and especially the Pectinibranchia and
Pulmonata, have a highly-developed superior and inferior ganglionic mass ;
the oesophageal ring is formed by these ganglia, being connected on each
side by a cord, which is oftener double than single.® The superior mass
is composed usually of two ganglia which are connected by a transverse
commissure, or are contiguous, and sometimes even blended together.®

The inferior mass also presents many variations. With some species it
consists of a circle of distinct ganglia, connected by commissures ;(10> while
with others, it is composed of a group of ganglia more or less fused
together. <n)

§ 209.

With many of the Cephalophora,® there is a Splanchnic nervous system.
This can be divided into a Plexus splanchnicus anterior and posterior.
The first is composed usually of a double Ganglion pharyngeum inferius,
connected by a transverse commissure, or contiguous, but rarely blended
together. They are situated under the oesophagus and connect with the
cerebral mass by two filaments ; they send off nerves principally to the
pharynx, to the oesophagus and the salivary glands; and when the posterior
plexus is wanting, they send nerves also to the liver and the genital glands.®

1 This oesophageal ring is composed of eight gan-
glia with Tcrgipes ( N ordmann , loc. cit. p. 35,
Tab. II.), but with Actaeon , there are only seven,
the lower one of which, asymmetrical, sends two
very long cords of communication to two large
cerebral ganglia, while the two lateral ganglia con-
nect by a short commissure passing under the
oesophagus ( Allman , loc. cit. p. 194, PI. VII. fig.
1). According to a communication which Kolliker
has made to me, this ring, with Flabellina , has
only live ganglia.

8 See Barthold , in Muller's Arch. 1835, p. 378.

9 There is a transversal commissure between the
two cerebral ganglia with Patella , Haliotis , Pha-
sianella , Janthina , Turbo , Paludiiia, Lijmna-
eus , Plan or bis, and with many other species having
a shell. These two ganglia are contiguous with
Helix , Limax , and Cypraea ; but they are fused,
into one with Buccinum , Mur ex, Oliva, Harpa ,
Voluta, and other Pectinibranchia.

19 Haliotis has two, and Patella four inferior
ganglia disposed transversely, which send off
from each side a double cord of communication to
the brain. With Ancylus , Lymnaeus , Planor-
bis, Physa , Succinea , Bulimus , the inferior por-
tion is composed of live to seven ganglia, unequal and
disposed asymmetrically, and connected together by

off eight pairs of nerves •, Part V. PI. II. fig. 13
(Doris), cerebral ganglia, five pairs, and a single
ganglion, — the pairs are symmetrically placed
with regard to the median line and give off fifteen
pairs of nerves ; the single or visceral ganglion
gives off four nerves which are distributed to the
organs of reproduction, to the stomach, to the two
hearts, and to the branchiae, and can be traced
into ganglia of the sympathetic system belonging to
these several organs } Part V. PI. XLIII. fig. 10
( Antiopa ), cerebral ganglia, six, and give off ten
or eleven pairs of nerves.

commissures ; see Barthold, loc. cit., and my ob-
servations in Wiesmann's Arch. 1841, I. p. 153,
Taf. VI. fig. 3 (Lymnaeus stagnalis). Judging
from the figure of Van Beneden (Exercices zoot.
loc. cit. Ease. I. Mem. sur le Lymnaeus gluti-
nosus, p. 30, PI. I. fig. 12, and Ann. d. Sc. Nat.
VII. 1837, p. 112, PI. III. B.), of the oesophageal
ring of Amphipeplea, this genus resembles, in this
respect, Lymnaeus. With Pneumodermon vio-
laceum (Van Beneden, loc. cit. p. 45, PI. I. fig. 2),
and with Clio (Eschricht, loc. cit. p. 6, Tab. III.
fig. 28), the lower portion appears also to consist
of a circle of ganglia.

11 Helix, Limax , Arion. With Limax (Pou-
chet , Recherch. loc. cit. p. 8), there remains in the
middle of the fused ganglia only a small opening,
which, with several species of Helix , entirely disap-
pears.*

1 See Brandt, Ueber der Mundmagennerven der
Evertebraten, loc. cit. p. 43.

2 The two ganglia of the Plexus splanchnicus
or Sympathicus anterior, which is situated more
or less in front of the inferior portion of the oesoph-
ageal ring, have, together with their correspond-
ing nervous filaments, already been regarded
by Cuvier as a sympathetic system, with several
Gasteropoda j see his M6m. sur le Genre Aply-

With all these genera, the oesophageal ring is
formed by lateral commissures which unite with the
sub-oesophageal ganglia which are sometimes two
(Dendronotus, Doto, Eumenis ), sometimes four
(Eolis, Doris, Antiopa). — Ed.

* [§ 208, note 11.] The nervous system of the
terrestrial Gasteropoda has been most carefully
described and beautifully figured by Leidy (loc.
cit.). The details are so full that I can only indi-
cate the work. — Ed.

236

THE CEPHALOPIIORA

§210.

The posterior plexus is composed of a single mass, rarely of two separate
ganglia. It is situated under the digestive canal or between its coils, and
from it pass off nerves to the intestine, the liver, and the genital glands,
beside two cords of communication with the lower portion of the oesophageal

ring.®

CHAPTER IV.

ORGANS OF SENSE.

§210.

The Tactile organs of the Cephalophora consist of two to four contractile
tentacles situated upon the head, or the anterior part of the back.(1) They
receive nerves of considerable size from the cerebral mass, which have some-
times a ganglionic enlargement in the extremity of the tentacle.® With
some Gasteropoda these tentacles are hollow and button-like at their ex-
tremity, and can be inverted like the finger of a glove.® But with the

sia, p. 23, PI. IV. fig. 1, c. •, sur la Lymnee, p.
9, PI. I. fig. 11, u. 5 sur l’Onchidie, p. 14, PI. I.
fig. 6, o. Brandt (Med. Zool. II. p. 328, Tab.
XXXIV. fig. 11, 13) has described it with Helix
pomatia ; Van Beneden (loc. cit.), with Amphi-
peplea , and Treviranus (Beobacht. aus. d. Zoot.
und Physiol, p. 42, Taf. IX. fig. 60), with Limax.
See also the researches of Sclilemm (Dissert, de he-
pate ac bile crustaceorum et molluscorum quorun-
dam, Berol. 1844, p. 22, Tab. I. fig. 2, 3), upon the
hepatic nerves of Gasteropoda. Belle Clviaje also,
has seen this plexus with Tioridium and Pleuro-
branckus (Memor. II. p. 123, Tav. X. fig. 7, p.
and III. p. 153, Tav. XLI. fig. 8, p.). According
to Garner (loc. cit.), there is a double Ganglion
pharyngeum inferius with, also, Scyllaea , Doris ,
and Eolis. With Patella , on the contrary, he
found this anterior Plexus splanchnicus composed
of three ganglia, two upon the sides, and the third
median and a little behind.

According to Van Beneden (Exercices zoot.
Fasc. I. p. 30, PI. I. fig. 12, c.), there is a similar
disposition with Amphipeplea. With the Hetero-
poda, this plexus is highly developed, composed of
two ganglia, from which pass off long cords of com-
munication to the cerebral mass ; see Milne Ed-
wards, Ann. d. Sc. Nat. XVIII. p. 327, PI. XI.
fig. 1, s. x. and fig. 2, e. f. 5 and Belle Chiaje ,
Descriz. &c. loc. cit. Tav. LXIII. fig 14, 1. and
LXIV. fig. 11, d. ( Carinaria and Ptero trachea).
The Pteropoda also have this plexus •, but its two
ganglia are more or less intimately fused, and as
the cerebral mass is here replaced by a simple col-
lar, it does not connect with it, but with the infe-
rior portion of the oesophageal ring •, see Van Be-
neden, Exercices zoot. Fasc. II. p. 11, et seq. PI. I.
fig. 9, 10, II. fig. 8, 10, III. fig. 6, 9, and V. fig.

*[§209, note 2.] For the splanchnic .nervous
system of the terrestrial Gasteropoda, see Lcidy,
loc. cit. PI. XIII. fig. IV. 2 ( Helicina ), PI. XIV.
fig. IV. 3 ( Glandina ), and PI. XVI. fig. II. 2
{Helix).

See also for that of the Nudibranchia, Alder

13 ( Cymbulia , Tiedemannia, Hyalea and Lima-
cina.) *

3 The Plexus splanchnicus posterior with its
two long cords of communication is quite apparent
with Aplysia (see Cuvier , loc. cit. p. 23, PI. IV.
fig. 1, II.). Belle Chiaje (Memor. Tav. V. fig. 1,
m, X. fig. 7, o. and XLI. fig. 8, y. y.), has observed
it with Boridium, and Pleurobranchus, be-
side the genus just mentioned , and in Pleuro-
branchus, he found it composed of two entirely
separated ganglia. Van Beneden (Exerc. zoot.
Fasc. I. p. 46, PI. I. fig. 3-5) has found it com-
posed of only a single ganglion with Pneumoder-
mon. Milne Edwards (loc. cit. p. 329, PI. XI.
fig. 1, u. v. 6), has observed in the visceral sac of
Carinaria, first, a double Ganglion abdominalc ,
which receives two long cords of communication
from the cerebral mass and from the Ganglion
pedale, and then a Ganglion anale, communi-
cating with the two abdominal ganglia.

1 There are most usually two tentacles. But with
Limax, Arion, Helix, Achatina , Clausilia, and
other Helicina, there are four. They are wholly
wanting with Sagitta, Cleodora, Cuvieria, Hya-
lea, Pterotrachea, Lissosoma, Rhodope, Phyl-
lidia, and Dentalium.

2 This swelling exists not only with the inferi-
or and eyeless tentacles, but also the superior ones
bearing eyes, with several Limacina and Helicina.
However, no ganglionic globules are seen in it, and
only a finely-granular substance lies interposed be-
tween the primitive fibres.

3 With the Limacina and Helicina, these organs
are invested by a muscle which arises upon the
columnella or upon the internal surface of the
mantle, and is inserted at the extremity of each
tentacle.

and Hancock , loc. cit. {Eolis, Doris , Antio-
pa, &c.).

According to Middendorff (loc. cit. p. 76), Chi-
ton has a complex splanchnic nervous system
which is widely distributed over the digestive or-
gans and their auxiliary glands. — Ed.

§ 211.

THE CEPHALOPHORA.

237

majority of the Cephalophora, they are solid and usually conical, and some-
times are replaced by two groove-like, cutaneous processes, which, from
contractions of their muscular fibres, can be shortened, but not inverted.'4'

Beside these tentacles, many Cephalophora have also as tactile parts,
organs, which consist of two contractile lobes situated on each side of the
cutaneous fold which rests over the mouth like a second lip.(5) The prehen-
sile organs about the mouth of certain Pteropoda, and the contractile fila-
ments and processes on the border of the mantle of other Cephalophora, are
also used, probably, as tactile parts.®

§ 211.

The organs of Hearing, which as yet have been found in all the orders
of these animals, are, as in the Acephala, of a very low order. Like them
also they consist only of two simple round auditive capsules whose transparent,
solid walls contain sometimes a single, sometimes several otolites, suspended
in a clear liquid, and which are composed of carbonate of lime.(1) When

4 With the Pectinibranchia, there are usually
two conical tentacles j more rarely are there four
as with Amphorina , Eolidina, F labellina , and
Aeolis. Cutaneous furrow-like prolongations are
observed with Notar chus, Dolabella , Pleuro-
branchus, Pleurobranchaea, and Aplysia. With
Doris , Tritonia , and Scyllaea , the two conical
tentacles can be withdrawn into particular tubular
excavations of the mantle.*

5 F labellina, Aeolis, Doris, Phyllidia , Dori-
dium, Aplysia, Pleurobranchus, Pleurobran-
c.haea , Dolabella, Ampullaria, Ceratodcs. These
cutaneous lobes are often so large, that one is dis-
posed to include them among the real tentacles.

6 I refer here to the tentacle-like organs by which
Clio, Pneumodermon, and Spongiobranchaea
fix themselves upon marine bodies (§ 204), to the
filaments of the anterior lobes of the mantle of
Thetis, Plocamophorus, and Tritonia thetidea,
and to the prolongations of the lateral border of the
same organ with Haliotis, Doris Jimbriata, and
Cypraea erosa.

1 Eudoux and Souleyet (Institut. 1838, No.
255, p. 376, or Froriep's neue Not. No. 174,

1838, p. 312,) were the first to notice the auditive
organ with the Cephalophora. They found with
Pterotrachea, Carinaria , Pneumodermon, and
Phyllirrhoe , as also Gaudichaud with Atlanta,
that the auditive capsules are small round semi-
transparent bodies attached by a peduncle upon
the cerebral mass. Laurent (Append, aux re-
cherch. sur les organes auditifs des Mollusques, in
the Ann. franc, et etrang. d’Anat. et de Physiol.
Mai, 1839, p. 118, fig. 1-16) has described these
organs with their crystalline contents a little more
fully, for, beside the figures of Eudoux and Sou-
leyet relative to Hyalea, Cleodora, and Creseis ,
he has added others concerning Limax and Helix.
Since then these organs with their otolites of differ-
ent Ileteropoda, Pteropoda, and Gasteropoda have
been described in detail by Krohn (Muller’’ s Arch.

1839, p. 335, or Froriep\s neue Not. XIV. 1840,
p. 310, XVIII. 1841, p. 310). In another series
of the terrestrial and fresh-water Gasteropoda, I

* [ § 210, note 4.] Hancock and Embleton
(loc. cit.) regard these tentacles as olfactory organs,
a view which is sustained by their special anato-
my, by their special and comparative relations.
Moquin-Tandon also (Bibl. Univer de Geneve.
Nov. 1851, p. 247) regards this sense as located in
the end of the tentacles, with the Gasteropoda

have attempted to show the analogy of these organs
with the auditive organs of the embryos of fishes
(JViegmann's Arch. 1841, I. p. 148, Taf. IV. or
Ann. d. Sc. Nat. XIX. 1843, p. 193, PI. II. 13.).
Kolliker (Ueber das Gehdrorgan der Mollusken,
in Froriep's neue Not. XXV. 1843, p. 133) also
has described them with many marine Ileteropoda,
and Gasteropoda, so that they may be said to exist
in all the Cephalophora which have been subjected
to dissection. The following are the genera in
.which they have been observed. Among the Pter-
opoda : Cymbu/ia, Tiedemannia, Hyalea, Cre-
seis, Pneumodermon, Limacina Ileteropoda :
Carinaria, Pterotrachea, Phyllirrhoe, Atlanta $
Gasteropoda : Rhodope, F labellina, Lissosoma ,
Amphorina, Pelta, Clialidis, Zephyrina , Actae-
on , Actaeonia, Aeolis , Venilia , Tergipes , Do-
ris, Poly c era, Tritonia, Thetis, Diphyllidia,
Ancylus, Doridium, Aplysia, Gasteropteron,
Umbrella, Not.archus, Pleurobranchus, Pleuro-
branchaea, Paludina, Lymnaeus, Planorbis,
Physa, Bulimus , Clausilia, Succinea , Helix,
Arion, and Limax. It is remarkable that the
auditive organs are developed so early, for they
may be distinguished while the embryo is still in
the egg. From the account of Pouchet (Ann. d.
Sc. Nat. X. 1838, p. 64), it appears that he saw the
otolites in motion in an embryo of a Lymnaeus,
but without knowing their nature. Lov&n also,
who saw the two capsules in the young Eolis
(Kongl. Vetensk. Acad. Handl. 1839, p. 227, or
Isis, 1842, p. 360, Taf. I. fig. 1, o.) did not know
what to think of them. Van Beneden (An. d. Sc.
Nat. XV. 1841, p. 127, PI. I. fig. 13, 15, 17, d.)
mistook them in the embryos of Limax and Aply-
sia, for nervous ganglia j while Allman (loc. cit.
p. 153, PI. VII. fig. 10-12, d.) regarded them as
eyes in the embryos of Actaeon. Sars (IVieg-
mann's Arch. 1845, I. p. 8, Taf. I. fig. 7-11) and
Nordmann (loc. cit. p. 44, 87, Tat'. IV. V.),on the
other hand, very correctly recognized them as or-
gans of hearing in the embryos of Doris , Trito-
nia, Tergipes , Buccinum, Littorina, Cerithium ,

See also Hancock (Ann. Nat. Hist. 1852, IX. p.
188) on this apparatus with the Bullidae. In these,
no proper tentacles exist, as is well known, but this
author shows that here the head-lobe, which is the
result of the fusion of tentacles, is the seat of this
sense. — Ed.

238

THE CEPIIALOPHORA.

§ 211.

single this otolite is spherical and crystalline, but when multiple they are
fusiform, a little compressed, and usually Very numerous, there being with
some Gasteropoda, thirty or forty, and even eighty in each capsule.®

The movements of these bodies are even more marked with the Cephal-
ophora than with the Acephala ; and the balancing and rotation of each,
producing a kind of trembling of their whole mass which occupies the cen-
tre of the capsule, is a wonderful spectacle. It has been recently discov-
ered that these motions are due to very small cilia upon the internal surface
of the capsule.®

The situation of these two auditive capsules varies according to the
orders, families, and genera. With several Heteropoda, and Apneusta,
they lie a little under the skin, behind the eyes, and are connected with the
cerebral mass by a longer or shorter auditive nerve. (4) In some Nudi-
branchia, they lie upon the cerebral mass itself, contiguous with the pos-
terior part of the eyes.® With the other Cephalophora, they are situated
at the lower side of the body, and usually touch the inferior portion of the
oesophageal ring. In only a very few of the genera are the two auditory
nerves separated and distinct from each other.®

Phasianella , and Rissoa. I have myself seen
them quite early in the embryos of Vermetus .*

2 There is a single otolite only with the Hetero-
poda, the Tubulibranchia and several of the Ap-
neusta *, see Delle Chiaje , Descriz. &c. II. p. 100,
Tav. LXIII. fig. 5, 6 ( Carinaria ), and Quatre-
fages , Ann. d. Sc. Nat. 1. 1844, p. 160, PI. VI. fig.
8-10 ( Actaeon, Pelta , Chalidis). According to
Krohn* s and my own observations, there are
groups of small fusiform otolites with some Ptero-
poda, and very many of the Gasteropoda, as Cyrn-
bulia , Hyalea , Doris , Tritonia , Thetis, Aeolis ,
Venilia, P Leurobranchaea, Paludina , Planorbis ,
Lymnaeus , Helix, Limax, and many others. It
is not rare to find among these fusiform otolites,
others composed of two or four calcareous corpus-
cles. Those of a spherical or spindle shape divide,
from pressure, into four to eight fragments in the
direction of cruciform lines which may often be seen
before division. According to the observations of
Laurent, Krohn, and myself, in the centre of
these bodies, a single otolite is first developed, in the
capsules which are to contain several, and others
are added as the embryo increases \ see Frey, in
Froriep's neue Not. XXXVII. No. 801, p. 132,
and fViegmann's Arch. 1845, I. p. 217. Taf. IX. t

3 A priori, it might have been inferred that these
motions are due to cilia, for the otolites never come
in contact with the sides of the capsule, but al-

* [ § 211, note 1.] See also Alder and Hancock
ioc. cit. Part II. PI. II. fig. 11 ( Dendronotus ), PI.
IV. fig. 18 (Doto); Part. III. PI. VIII. fig. 4, 5,
6 (Aeolis) ; Part V. PI. II. fig. 15 (Doris) ; then
Ley dig, Ueber Paludina vivipara, &c., Ioc. cit. p.
139, 155, Taf. XI. fig. 12, k. Taf. XIII. fig. 14-24,
49, R. (Paludina) ; and Leidy, loc. cit. p. 246, PI.
IX. fig. VII.-IX. (Helix), PI. XIII. fig. IV. 4
(Helicina). Leydig has furnished valuable con-
tributions in the development of this organ *, in Pa-
ludina, it appears, prior to the nervous system
with which it is connected, as an almost solid body
with a very small, round, central cavity ; with the
growth of the organ, this cavity increases, and
finally the whole becomes a capsular organ in which
are developed otolites. — Ed.

ways remain at a little distance from it, and when
there are several, they are grouped in the centre 5
indeed when one has strayed from this central jjo-
sition it is always quickly returned. JVagncr
(Lehrbuch der Physiol, ed. II. 1843, p. 463) positive-
ly affirms that he has seen cilia in these capsules.
They have been very distinctly seen by K 6 llilcer
also (loc. cit.) with Tritonia, Thetis, Pleuro-
branchaea, Diphyllidia , Hyalea, Lissosoma, and
Rhodope.

4 See Laurent, loc. cit. fig. 1-6, and Quatre -
fages, Ann. d. Sc. Nat. I. loc. cit. PI. IV. VI. Ac-
cording to Delle Chiaje (Descriz. &c. loc. cit. Tav.
LXIII. fig. 3, d. 14, f.), and Milne Edwards
(Ann. d. Sc. Nat. XVIII. 1842, PI. XI. fig. 1, z.
fig. 3, h.), the auditive nerves are very long with
Carinaria. With many Cephalophora which are
transparent, the auditive organs may be perceived
by the naked eye, through the skin, as two white
spots. J

■5 Doris, Thetis, Tritonia, Aeolis (Krohn, loc.
cit.), and Tergipes ( Nordmann , loc. cit. p. 44,
Tab. II.).

6 According to Krohn (loc. cit. No. 394, p. 311)
the two auditive capsules of P leurobranchaea, and
Paludina receive distinct auditive nerves from the
inferior portion of the oesophageal ring. He has
observed the same with Cymbulia , and Hyalea
(loc. cit. No. 306, p. 311) ; but Van Beneden (Ex-

f [ § 211, note 2.] See, for the auditory appara-
tus of Aeolis, Hancock and Embleton , Ann. Nat.
Hist. 1849, III. p. 196. The otolites which have
hitherto been regarded calcareous, they found not
to be materially affected by long treatment with
acetic acid. — Ed.

| [§ 211, note 4.] See also Leydig (Anat. Be-
merk. ub. Carinaria, Firola und Amphicora, in
Siebold and Kblliker's Zeitsch. III. 1851, p. 325).
His Taf. IX. fig. 4 (Carinaria) gives a very clear
idea of the structure and relations of the auditory
capsules with these animals. His observations
upon the cause of the movements of the otolites are
confirmatory of those of Milne Edwards with
Firola ; see L’Instit. Jour. univ. des Soc. sav. XIII.
1845, p. 43. — Ed.

t

§ 212.

THE CEPHALOPIIORA.

239

§ 212.

The organs of Vision are absent with only a very few genera of the Ce-
phalophora.® They are never more than two in number, and their size, com-
pared to that of the body, is usually small ; they are smallest with some
Heterobranchia., and the largest with the Pectinibranchia.®

The eyes consist usually of two round bulbs concealed under the skin ;
this last is colorless at this point, and lies over them like a thin lamella. Each
bulb is limited outwardly by a tissue resembling a Sclerotica, but beneath the
skin, this tissue is more convex than elsewhere, and thus forms a kind of Cor-
nea.® The sclerotica is lined by a dark pigment layer, or Choroidea, which,
near the corner, ends in a free border, forming thus a Pupilla. With some
Gasteropoda, the pupillary border has a very thick pigment layer which
serves, perhaps, as an Iris.(i>

The internal surface of the choroidea is covered by a whitish pellicle
which undoubtedly is a Retina , for the optic nerve enters the sclerotica at
a point opposite the cornea.® The cavity of the eye-bulb is filled with a
gelatinous, vitreous body, which, in front, envelops a spherical crystalline
lens.®

The Optic nerve arises from the cerebral ganglia, and runs along, for a
longer or shorter distance, in company with the tentacular nerve of the
same side.®

ere. zoot. Fasc. II. p. 13, PI. I. fig. 8, f. 9, c. 10,
PI. V. fig. 13, x.) affirms that with the first of these
genera, and with Tiedemannia , and Limacina , the
auditive vesicles lie directly upon the two principal
inferior ganglia 5 this agrees with Delle Chiaje's
description of these organs with Cymbulia ; see his
Descriz. &c. I. p. 94, Tav. XXXII. fig. 2, i.
Eschricht (loc. cit. p) 6, Tab. III. fig. 28, s.) has
figured, with a Clio , two ganglia with short pe-
duncles, situated close by the two anterior ganglia
of the oesophageal ring. These, I infer, are only
the auditive capsules receiving two short auditive
nerves.

With those Gasteropoda whose inferior oesophageal
ganglia are arranged in a circle, as, for examples,
with Lymnaeus , Plnnorbis , Physa , Succinea ,
Bu/imus , Ancylus , these capsules lie upon the
posterior surface of the two large anterior ganglia.
But when, on the other hand, these ganglia are
approximated, or even fused into one common mass,
as with Helix , these capsules lie upon the inferior
surface of this mass, and especially upon the
nodules corresponding to two large anterior ganglia.

1 Phyllirrhoe , Diphyllidia , Chiton , Dentali -
wm, and the Pteropoda with the exception of Sa-
gitta and Clio, are blind. In many of the Ptero-
poda, the auditive appear to have been taken for
the ocular organs.

2 Swammerdamm (Bibel der Nat. p. 47, Tab. IV.
fig. 5-8) made out very correctly the structure of the
eyes of Helix. The later works of Stiebel ( Meck-
el's Deutsch. Arch. 1819, p. 206, Tab. V.), Hu.sc hke
(Beitr. zur Physiol, u. Naturgesch. 1824, p. 57,
Taf. III. fig. 8), and of De Blainville (De l’Organ-
isat. des Animaux, 1823, p. 445), upon the eyes of
Helix , Paludina , and Voluta, have been much
improved by those of Muller ( Meckel's Arch.

* [ § 212, note 4.J For the visual organs of Pa-
ludina, with histological details, and especially
confirmatory of Krolin's observations, see Leydig ,
loc. cit., Siebold and Kulliker's Zeitsch. II. 1850,

1829, p. 208, Taf. VI. fig. 4-8, and Ann. d. Sc.
Nat. XXII. 1831, p. 7, PI. III. IV., or in the Isis,
1835, p. 347, Taf. VII.), and Krohn (Muller's
Arch. 1837, p. 479, 1839, p. 332, Taf. X. fig. 6-8)
upon the eyes of Helix, Mur ex, Paludina , and
Pterotrachea.

3 The eyes of the Ileteropoda present a remark-
able exception •, their very convex cornea is sur-
rounded by a collar of skin ; the ocular bulb is very
long, and, at its base, the sclerotica spreads out
interiorly and posteriorly, forming a round prom-
inence *, see Milne Edwards, Ann. d. Sc. Nat.
XVIII. 1842, PI. XI. fig. 1, c. ( Carinaria ), and
especially the description of Krohn (loc. cit. 1839)
of the eye of Pterotrachea. The ocular bulb of
Clio is also very long, but has no prominence } see
Eschricht , loc. cit. p. 7, Tab. III. fig. 29. Those
of Actaeon are long and pyriform 5 see Quatre-
fages , Ann. d. Sc. Nat. I. 1844, PI. VI. fig. 5, and
Altman , loc. cit. PI. VII. fig. 2.

1 A dark iris is distinctly seen with Paludina
and Mur ex. That of Strom bus is very brilliant
and multicolored, according to Quoy and Gai-
mard ; see, Voy. de 1’ Astrolabe, Zool. III. p. 56, Mol-
lusques, PI. L. LI. 1 am not yet certain whether
or not the iris of these Gasteropoda is susceptible
of movements of contraction and dilatation. It
may be well to add that the choroidea of the Ile-
teropoda has several spots of its surface free from
pigment.*

6 Krohn (loc. cit. 1837, p. 482) affirms that he
has seen this white layer with a Paludina.

<» The existence of a distinct vitreous body was
known to Swammerdamm, and has been confirmed
by Krohn (loc. cit. 1837).

7 According to Krohn (loc. cit. 1839), the two
optic nerves of Paludina , Murex, Aplysia, Cy-

p. 159, Taf. XII. fig. 25, Taf. XIII. fig. 26-2S.
See also this same author in Siebold and Kdlli-
ker's Zeitsch. 1851, III. p. 327 (Carinaria). — Ed.

240

THE CEPHALOPHORA,

§ 212.

There is, moreover, a series of Cephalophora with which the eyes are
much more simple and often nearly abortive. Such is the case with Sagitta,
and many of the Apneusta and Heterobranchia.® Here, the eyes are
not always nicely limited by a sclerotica, but the light-refracting bodies lie
surrounded in a mass of pigment granules, and situated more or less dis-
tant from the external surface of the cervical region. The cornea is absent,
and often also the optic nerve, in which case, the eyes lie directly upon the
cerebral mass.®

The most complete eyes are nearly always connected with the tentacles,
although their position varies quite widely. (10) Very often they are situated
at the base of the external surface of these organs. (U) With many Pectini-
branchia, they are more or less elevated upon the outer side of the ten-
tacle on a protuberance or on a support which exceeds the extremity of the
tentacle in length and size.(12) With many Pulmonata, these organs are
situated upon the very extremity of the tentacles, and are upon the pos-
terior pair, when these last are four in number.(13>

praea, Rostellaria , Buccinum , and Littorina ,
arise from the cerebral ganglia by an origin which
is distinct from that of the tentacular nerves. I
have been able to confirm this for Helix , Limnx ,
Caracolla. According to Muller (Ann. d. Sc. Nat.
loc. cit. p. 12, PI. III. fig. 5), the optic nerve is
only a special branch of the end of the tentacular
nerve.

# The two pretty simple eyes of Sagitta , forming
two prominences on the top of the head, are spher-
ical, and rest directly upon the ganglionic enlarge-
ment of the optic nerve , see Krohn , loc. cit. p. 13,
tig. 5, 14.

'•> According to Quatrefages (loc. cit. I. p. 158,
PI. V I. fig. 6, 7), the eyes of Pelta , and Chalidis ,
have, instead of a choroidea, a mass of pigment
containing neither a sclerotica nor a cornea. Ac-
cording to the observations of Nordmann , and
Kolliker , the eyes of Tergipes and Polycera are
without optic nerves, and lie directly in contact
with the cerebral ganglia. With Doris , Glaucus ,
Thetis , Aeolis , Doridium , Aplysia , Bulla , Bul-

* [ § 212, note 9.] For the eyes and their inti-
mate structure with the Nudibranchia, see Alder
and Hancock, loc. cit. ( Dendronotus , Dolo , Aeo-
lis , Scyllaea , Eumenis , Doris , Antiopa) ; with all
these, the optic nerves were distinct, and the eye
itself was furnished with a well-rounded, black pig-
ment-cup, often a spherical crystalline lens (Doris,
Aeolis , Antiopa ), with an arched cornea in front,
and the whole enveloped by a transparent mem-
branous capsule. — Ed.

t [ § 212, note 13.] See, in this connection, Lespis
(Recherches surl’oeildes Mollusques Gast^ropodes
terrestres et fluviatiles de France, Thesis. Tou-
louse, 1851). His conclusions are :

“1. All the terrestrial and fluviatile Gastero-
poda have eyes *,

“ 2. These organs present, as to their position,
three different types :

laea, &c., these organs are comparatively small
and appear more or less distinct through the skin,
sometimes in front of, and sometimes behind, the
tentacles.*

10 This is so with various Heteropoda, all the
Pulmonata, Pectinibranchia, and with some of
the Heterobranchia ; see Lovin , loc. cit. and
Isis, 1842, p. 364.

11 The eyes are situated at the base of the tenta-
cles on a small prominence, with Carinaria , At-
lanta, Vermetus , with the Lymnaeacea, the Oper-
culata, Patella , Emarginula , Fissurella , Siga-
retus , Paludina , Littorina. A kind of peduncle
replaces this prominence with Haliotis , Navicella ,
Phasianella , Trochus , Ceratodes , Ampullaria.

12 The prominences supporting the eyes are situ-
ated on the outer side of the tentacles with Bucci-
num, Harpa, Dolium , Cypraea , Murex, Oliva,
Turbo ) and at a variable distance from the ex-
tremity which they sometimes surpass in breadth
and length, as, for example, with Strombus.

13 Amphipneusta, Helicina, and Limacina.t

“(1.) The eye at the extremity of the tentacle
(Helix) ;

“(2.) The eye at the internal base of the tenta-
cle (Limnaea) ;

“(3.) The eye at the external base of the tenta-
cle ( Cyclostoma ).

“3. These organs present also three types as to
their organization :

“(1.) The lenticular crystalline lens, the vitre-
ous humor fluid, non-adherent (Helix) ;

“ (2.) The lenticular crystalline lens, the vitreous
humor thick and united to this last *,

“(3.) The crystalline lens thick and slightly con-
vex, the vitreous humor viscous and slightly ad-
herent to the lens.” — Ed.

4

§ 213.

THE CEPHALOPHORA.

241

CHAPTER V.

DIGESTIVE APPARATUS.

§ 213.

The highly-developed digestive organs of the Cephalophora always com-
mence at the anterior extremity of the body, with a round, oral orifice,
which is surrounded with tumid lips, but rarely has special prehensile
organs. (1) These lips are quite contractile, and can evert and invert the
mouth ; with many species, they can be prolonged into a cylindrical pro-
boscis.® The walls of the oral cavity are very muscular, and, with the
majority of the species, form a round and often very large pharynx. The
epithelium of this cavity is frequently developed into collars or callosities
which serve as masticatory organs. With some Gasteropoda, this apparatus
is composed of two horny, lamelliform jaws, which have a truncate, convex,
internal border, and move upon each other in a lateral manner.® These
jaws are situated, sometimes directly behind the oral orifice, and sometimes
at the base of the pharynx.

Many other Gasteropoda have only an upper jaw enchased in the roof
of the oral cavity, and which is easily seen from its deep-brown color. It
consists of a transverse, semilunar, horny plate, upon whose anterior surface
are several vertical crests, which terminate upon the free border by as
many tooth-like processes.®

Nearly all the Cephalophora have a longer or shorter fleshy mass, ad-
hering to the base of the pharynx, and which is sometimes grooved longi-
tudinally ; it is quite comparable to a Tongue. Sometimes it is very large
and contained in a membranous sheath at the base of the pharynx. It is
always armed with horny, denticulated spines and plates, which are very deli-
cate, and arranged in quite elegant, longitudinal and transverse rows. The

1 Such are the tentacular appendages which have
a sucker, of Pteropoda (Clio, Spoil giobranchaca,
and Pneumodermon), already mentioned above
(§ 204).

2 There is a retractile proboscis with Pneu-
modermon, Spongiobranchaea, Pterotrachea ,
Thetis, Buccinum , Dolium, Cypraea , Mur ex,
Conus, Voluta , and many other Pectinibran-
chia.

3 The external borders of these jaws are easily
perceived between the lips, as with ScyUaea (Cu-
vier, Mem. loc. cit. fig. 6, a. 6, b.), with Tritonia
(Savigny, Descript, de l’Egypte, Hist. Nat. II.
PI. II. fig. 1*-110, and Delle Chiaje, Descriz. loc.
cit. Tav. XLII. fig. 1), into with Diphyllidia and
Bulla. They are found Tllso directly behind the
lips with Venilia , Aeolis, Amphorina, and Ter-

' gipcs (Alder, Hancock and jE mbleton, Ann. of
Nat. Hist. XIII. p. 162, PI. II. fig. 3, 4, XY. p. 4,
PI. II. •, also Quatrefages, Ann. d. Sc. Nat. I. p.

* [ § 213, note 4.] For many details upon the
oral organs of the Helicina, of an anatomical as
well as a zoological import, see Troschel (Ueber

147, PI. V. fig. 5, and Nordmann , loc. cit. p. 12,
Tab. I. fig. 7). With Dentalium, on the contrary,
the jaws are situated at the base of the oral cavity
(Dcshayes, loc. cit. p. 333, PI. XV. fig. 11, b. b.
15, 16, or in the Isis, 1832, p. 463, Taf. VI. fig. 15,
19, 20).

4 This upper jaw is particularly developed with
the Limacina and Helicina ; see Cuvier, M£m. loc.
cit. Sur la Limace, &c., PI. II. fig. 4 (Limax) ;
Troschel , in IViegmann's Arch. 1836, I. p. 257,
Taf. IX. fig. 3-9 (Arion, Limax, Helix, Clau-
silia, and Succinea ), and Erdl, in Mor. Wag-
ner's Reisen inder Regentsch. Algier. III. p. 268,
Tab. XIII. XIV. With Lymnafus, and Planor-
bis, there are, beside, two small lateral jaws ; these
exist also with Valvata, and Paludina, where the
upper jaw is wanting. With Zephyrina, there are
also three jaws at the base of the pharynx •, see
Quatrefages, loc. cit. I. p. 132, PI. V. fig. 1.*

die Mundtheile einiger Iielicien, in Wiegmann's
Arch. 1849, p. 225). — Ed.

242

THE CEPHALOPIIORA.

$ 214,

points of these spines turn backwards, and thus the retractile tongue can
serve as an organ of ingestion, and as such is used with much address.®

§ 214.

The intestinal canal has often longitudinal folds and a ciliated epithe-
lium extending from the oesophagus to the rectum, and even into the
hepatic ducts.® It is usually two or three times the length of the body,
and has therefore several convolutions, which, with the species which have
a shell, are contained in its spiral cavity.

It commences at the base of the pharynx by an (Esophagus, of variable
length, which is sometimes dilated at its posterior extremity into a kind of
crop.® The stomach, which, from constrictions,® is often divided into
several portions, consists sometimes of a simple dilatation with thin
walls,® and at other times of a nicely-defined cavity whose walls are thick
and fleshy,® and provided, sometimes, with thick epithelium, and even, in
certain cases, with plates and horny teeth.® The cardiac and pyloric ori-

See the description and figures of Troschel
(loc. cit. Taf. IX. X.) of the tongue of our terrestri-
al and fresh-water Gasteropoda, and also of Am-
phipeplea (Ibid. 1839, I. p. 182, Taf. Y. fig. 8).
For that of the marine Gasteropoda, see principally
Quoy and Gaimard (loc. cit.), also Poli, Testacea
Siciliae, &c., I. p. 5, Tab. III. fig. 9 (Chiton), Sa-
vigny , Desc.vip. de i’Egypte, Hist. Nat. II. PI. II.
fig. 2'J-213, III. fig. 57, 5* ( Aplysia and Chiton ),
Rang , Hist. Nat. des Aplysiens, PI. XX. fig. 9-13
(Aplysia), Delle Chiaje , Memor. &c. Tav. XV.
fig. 7-10 ( Carinaria ), and Eschricht , loc. cit. p.
10, Tab. III. fig. 20-23 (Clio).

The tongue is very long with most of the Ap-
neusta 5 see Quatrefages, loc. cit. I. PI. IV. V.
(Actaeon and Amphorina), Alder , Hancock and
Embleton, Ann. of Nat. Hist. XIII. PI. II. fig. 5-6,

XV. PI. I. II. (Venilia and Aeolis ), Allman, Ibid.

XVI. PI. VI. VII. fig. 5 (Actaeon), and Nord-
mann, loc. cit. Tab. I. fig. 7-10 (Tergipes). With
Patella , this organ nearly exceeds the body in
length, and bends loop-like, near its posterior ex-
tremity (Cuvier, Mem. loc. cit. PI. II.). With
Trocfius pagodus, it is seven times longer than the
body (Quoy and Gaimard, loc. cit., and Isis. 1836,
p. 69, Taf. IV. fig. 3). With Pleurobranchaea ,
there are spines, not only on the tongue, but
on a considerable portion of the lateral walls of
the oral cavity. To the same category belong the
spines which Eschricht (loc. cit. p. 9) found
upon the pharynx of a Clio, and described as
lateral teeth. This apparatus with Pneumo-
dermon is quite remarkable — being composed of
two tongues which are contained in two coecal
sheaths (Van Beneden , Exer. zoot. loc. cit. Fasc.
I. p. 47, PI. II. fig. 2). With Pterotrachea, the
tongue consists only of a simple transversal row of
curved spines. The circle of hooks surrounding
the mouth of SagHta may also be regarded as an
abortive tongue ( I&rohn , loc. cit. p. 7, fig. 3-6), for
they are exactly like the lingual spines of Ptero-
trachea (Delle Chiaje , Mem. loc. cit. Tav. LXIX.
fig- !)•

Lebert has given a very detailed description of
the parts of the mouth and the tongue of Patella ,
Buccinum, Doris, Haliotis, Paludina , and Li-
max ; see Muller's Arch. 1846, p. 435, Taf. XII.
-XIV.

1 The intestine is lined with cilia, with Patella,
Buccinum (Sharpey, Cyclop, of Anat. 1. p. 620),
Lymnaeus stagnulis , Paludina vivipara , and
Helix cellularis (Purkinje and Valentin , De

Phaenom. motus vibrat. loc. cit. p. 48), and with the
Apneusta (Quatrefages, Ann. d. Sc. Nat. I. p. 166).

1 have also seen the ciliary motions, with Lym-

naeus, Planorbis , and Clausilia ; but not with
Limax, Arion, Helix. Valentin may.

therefore, be mistaken in affirming (Wagner's
Handworterbuch d. Physiol. I. p. 492) that ciliated
epithelium exists generally in the intestine of the
Gasteropoda.

A ciliary movement has also been observed in
the intestine of Sagitta by Krohn (loc. cit. p. 8),
and by Wilms (Observ. de Sagitta, Diss. Berolini,
1846, p. 12).

2 The oesophagus is very long with Buccinum,
Paludina, Lymnaeus, and Planorbis ; but very
short with Thetis, Haliotis , Tcstacella , Helix ,
and Limax. It has a kind of crop close upon the
stomach with Cymbulia, Onchidium, Lymnaeus ,
and Planorbis, while with Buccinum , and Volut.a,
a long, crop-like caecum arises from the upper por-
tion of the stomach near the oesophagus.

3 Aplysia, Dolabella, Notarchus , Ancylus ,
Pleurobranchus, and Onchidium ; see Cuvier ,
M£m. loc. cit. I am unable to say anything upon
the crystalline, gelatinous stem, which, according
to Cuvier (Edinb. new Philos. Jour. VII. 1829, p.
225, and Isis. 1832, p. 815) is found in all the
species of Strombus and some of Trochus and
Mur ex, and is contained in an internally projecting
appendix of the stomach.

4 Cypraea , Cassis , Murex , Testacella , Limax ,
Helix , &c.

5 Lymnaeus, Planorbis , Thetis.

6 There are three horny lamellae in the stomach
of Bullaea (Cuvier, loc. cit. fig. 11), and of cer-
tain species of Pleurobranchus ( Meckel , Beitr. &c.
I. lift. 1, p. 31, Tab. V. fig. 36, 37) *, four in that of
Cymbulia, Tiedemannia , Hyalea, and Limacina
(Van Beneden , Exerc. zpot. loc. cit. Fasc II.).

That of Pelta has fouiTAcnticulated horny plates
(Quatrefages, loc. cit. I. p. 153, PI. IV. fig. 5, V.
fig. 7), as is also true of Lissosoma , according to
Kolliker. With Scyllaea (Cuvier, loc. cit. fig. 6,
•d.), and with Tritonia ( Meckel , Syst. d. vergleich.
Anat. IV. p. 188), there is a complete row of lamel-
lae with sharp edges. With Dentalium also, the
entrance of the stomach has a very complicated
dental apparatus (Deshayes, loc. cit. p. 333, PI.
XV. fig. 13, or Isis. 1832, p. 463, Taf. VI. fig. 17).
But Aplysia, of all the Cephalophora, is best
provided for in this respect, for here the second
muscular stomach is lined with av triple row of

§ 214. THE CEPHALOPHORA. 243

Sees are, usually situated opposite each other ; but in some they are so
approximated that the stomach has the form of a caecum.®

The intestine, having made more or less numerous <8) convolutions, seldom
forms a rectum, but opens, usually, close by the respiratory orifice on
the right side of the anterior end of the body, and rarely at the posterior
extremity.® With the Pectinibranchia, the rectum often projects widely
into the cavity of the mantle, as a longer or shorter prolongation upon
whose extremity the anus is situated.

Sagitta and the Apneusta present wide differences from this just-
described type of structure. With the first, the mouth opens into a short
oesophagus which passes directly, without any stomachal dilatation, into
the intestine ; this last runs straight backwards, and, curving downwards,
terminates in the anus situated on the median line of the Ventral surface
at the posterior end of the body.(10) With the Apneusta, on the other
hand, there is a stomach with several and often highly-ramified caecal
appendages — which, in some species, extend even into the dorsal append-
ages. A short rectum follows directly upon the stomach, and ends in
an anus, often difficult to be found, and situated at the anterior part of the
right side of the body.(U)

cartilaginous lamellae, and the third has, beside,
numerous horny hooks which point forwards
(Cuvier, loc. cit. PI. III.).

7 Mur ex, Voluta, Sigaretus , Phyllidia , Di-
phyllidia , and many species of Doris and Cari-
naria.

8 The intestine is very short and slightly tortu-
ous with Clio , Car inaria, Thetis , Tritonia,
Diphyllidia , Pleurobranchaea , Buccinum , Mu-
rex, and Janthina. With the other Cephalo-
phora, it has usually many convolutions, which are
quite numerous especially with Haliotis, Patella,
and Chiton (Cuvier, loc. cit. PI. I.-III., and Poli,
loc. cit. Tab. III. fig. 6).

9 With the Pectinibranchia, and most of the
Pulrnonata, whose anus is near the respiratory
orifice, the position of the first is determined by
that of the last, and therefore is most usually upon
the right, and rarely upon the left side. This is
the case also with nearly all the other Gastero-
poda.

With Patella, it is situated directly back of the
head 5 with Tritonia, Scyllaea, and Thetis, a
little further back *, and even still more behind
with Diphyllidia, Dolabella, Notarchus, and
Pleurobranchaea. In this last genus it is above
the branchia, while in Pleuro branch us , and Aply-
sia, it is behind this organ. With Chiton, Phylli-
dia, Doridium, Bullaea, Testacella, and Onchi-
dium , it is at the very posterior end of the body.
With Doris, and Polycera, it is somewhat elevated
on the side of the back and surrounded by bran-
chiae.

With Haliotis, it is anterior and on the left side •,
and with Sigaretus , Fissurella , and Emarginula ,
it is even in front of the oral cavity.

Its position is varied with the Ileteropoda and
Pteropoda. With Carinaria, and Pterotrachea,
it is situated at the base of the intestinal sac, —
with Atlanta , upon a prolongation of the right side
of the neck *, with Phyllirrhoe, upon the middle of
the right side 5 with Pneumoderm on, directly
behind the right pinion 5 with Tiedemannia , at
the middle of the abdomen ; with Hyalaea, at the
same point but a little at the left ; and with Cym-
bulia and Limacina, in the respiratory cavity.
See, for these various positions, the works espec-
ally of Cuvier , Mechel, and Van Beneden.

10 Krohn, loc. cit. p. 8.

11 For the intestinal canal of the Apneusta, see
Milne Edwards , Ann. d. Sc. Nat. XVIII. 1842, p.

330, PI. X. fig. 2 (Calliopaea), also Quatrefages,
Alder, Hancock and Embleton , Allman, and
Nordmann , loc. cit. According to a communication
from Kbl/iker, that of Rhodope is the most simple 5
it consists only of a caecum which extends even to
the posterior extremity of the body, and near the
cardia sends off a short caecum which passes along
the left side of the oesophagus to the pharynx, and
upon the right side of the other end of the body
terminates in a short rectum. With Actaeon, ac-
cording to Souleyet (Compt. rend. XX. 1845, p. 94),
the intestine, after forming a stomachal dilatation,
bends, first forwards, then backwards, opening on
the right side of the neck. But the descriptions and
figures of this animal by Quatrefages (Ann. d. Sc.
Nat. I. p. 141, PI. IV. fig. 2, V. fig. 4) and Allman
(loc. cit. p. 148, PI. VI.), are remarkably contradict-
ory to these statements of Souleyet. According to
these authors, the stomach is followed by a short
rectum opening upon the right side of the neck,
which is attended by two superior and two in-
ferior intestinal tubes which send numerous ram-
ified appendages into the parenchyma of the body.
With Chalidis, the oesophagus is followed by lour
caeca, the two shortest of which extend in front,
and the others behind. With Pelta , there is a
large intestinal tube having many short coecal ap-
pendages, situated in the middle of the body. With
Aeolis, F lab e llina , Tergipes , which have only a
single intestinal tube closed posteriorly, and with
Zephyrina, Amphorina , and Calliopaea, which
have two such, the caeca from this canal extend
even into the dorsal appendages. With Eolidina ,
which has three intestinal tubes intercommunicat-
ing by numerous transversal anastomoses, these
last give rise to the caeca of the dorsal append-
ages. Quatrefages (Ann. d. Sc. Nat. XIX. p. 285,
PI. XI. fig. 2, c.), who at first declared that the
median tube of these animals opened by an anus
at the posterior end of the body, has since (Compt.
rend. XIX. p. 811) rectified this error ; for here,
as also with Actaeon, Aeolis, Tergipes, and Rho-
dope, the anus is anterior and on the right side.

A similar correction will perhaps be made with
Venilia, whose stomach, according to Alder and
Hancock (Ann. of Nat. Hist. XIII. p. 163, PI. II.
fig. 7), not only sends many ramified caeca into
the lateral appendages of the body, but also is fol-
lowed by a rectum, opening, they say, at the pos-
terior portion of the back.

244

THE CEPHALOPHORA.

§215.

§215.

With those Cephalophora which are nourished by solid food, and which
often have, therefore, masticatory organs, there are, almost without exception,
highly-developed Salivary organs. These are usually composed of two lob-
ular yellow glands surrounding the oesophagus or stomach, and which have
in front two excretory ducts which are lined with ciliated epithelium.(,)

These ducts pass, in company with the oesophagus, through the oesopha-
geal ring, and, extending over the base of the pharynx, end in the oral
cavity on each side of the tongue. With some species, these glands con-
sist of two very long tubes.® Some Gasteropoda have two pairs of these
organs, one of which opens at the anterior part of the mouth.® In a few
cases only these organs appear to be wholly wanting.®

The Biliary organs are always present; and their glandular follicles con-
tain hepatic cells filled with a brownish-yellow substance.® Most com-
monly, the liver is large and distinctly separated from the digestive canal ;
and it is with a few genera only that it is more or less blended with it.

1. This last is the case with some Pteropoda, and Apneusta, whose
intestinal walls, as with the Worms, are partly composed of the hepatic
substance, or furnished with numerous small follicles which open into the
intestinal cavity.®

1 Helix , Limax, Onchidium , Haliotis , Pleu-
robranchus , and the Pectinibranchia. For the
internal structure of these glands, see Muller , De
Gland, secern, struct, p. 54, Tab. XVIL*

2 Clio , Aplysia , Thetis , Lissosornu, Tergi-
pesy and many species of Doris.

3 Janthina, Flabellinay Actaeon, and Atlanta.
With some Gasteropoda, as for instance, with
Rhodope , and Eolidinay there are only two sali-
vary glands 5 these open in front into the oral
cavity and so far from the oesophagus that they
appear to correspond to the anterior pair of those
species in which there are four, t

4 Sagitta, Cymbulia, Tiedemannia, Denta-
liuWy and Chiton.

5 For the internal structure of the liver of the
Gasteropoda, see Muller, De Gland, secern. &c.
p. 71, Tab. X. *, Scblemniy De hepate ac bile Crus-
tac. et Mollusc, quorundam, loc. cit. p. 19, Tab. I.
II. ; Karsten, Nov. Act. Acad. Nat. Cur. XXI.
p. 304, Tab. XXI. •, and H. Meckel , Muller's
Arch. 1846, p. 9, Tab. I. {

6 With Sagitta , the hepatic substance appears

* [§ 215, note 1.] See also Leidy (loc. cit.) for
the salivary glands and their intimate structure, of
Limaxy Helix , TebennophoruSy Vaginula , Suc-
cinea , Glandina.

t [ § 215, note 3.] With Paludina , the salivary
glands are highly developed and two in number.
They are situated on the upper and posterior side
of the pharynx, behind the brain ; their excretory
ducts pass under the cerebral commissure, for-
wards, and perforate the upper wall of the pharynx.
In structure they consist of ramose caeca, made
up essentially of cylindrical epithelium situated on
a basement membrane 5 see Lcydigy loc. cit. p.
165, Taf. XII. fig. 10, a. b.

For further details on these organs with the
N udibranchiate Cephalophora in general, see

to be blended with the intestinal walls ( Krohn , loc.
cit. p. 8). This is distinctly so with Venilia , Aeolis,
Eolidinay Amphfpinay and Zephyrina , and is
especially seen upon the coecal ends of the
branches of the intestinal canal which terminate
partly in the dorsal appendages, and partly in the
parenchyma of the body ; see QuatrefageSy loc. cit.
XIX. p. 289, PI. XI. fig. 5, I. PI. IV. V. ; Alder,
Hancock and Embletoriy Ann. of Nat. Ilist. XIII.
p. 163, PI. II. fig. 9, XV. p. 80, PI. IV. According to
Nordmann (loc. cit. p. 20, Tab. II. III. fig. 3), the
liver is isolated with Tergipes ; but as the organ
here described appears to open externally by a
special duct, it resembles an urinary organ (see
below, § 223). With Pneumodermony and Clio,
the stomach is lined with a layer of small hepatic
follicles ( Cuvier , loc. cit. p. 8, fig. 7, p. •, and
Eschrichty loc. cit. p. 11).

According to a communication from Kblliker,
the intestine of Rhodope also has numerous folli-
cles of this kind, which are pyriform and filled
with cells having yellow nuclei.

Alder and Hancock , loc. cit. Part II. PI. IV. fig.

I, f. (Doto); Part III. PI. VII. fig. 6, a. (Aeolis) ;
Part IV. PI. V. fig. 1, c. ( Scyllaea ) j Part V. PI.

II. fig. 1, h. (Doris). — Ed.

J [§ 215, note 5.] See also Ley dig y Ueber Palu-
dina vivipara, &c., loc. cit. p. 143, 166 (Paludi-
na) ; he gives its development and its adult struc-
ture. It is developed from cells as an appendage
to the alimentary canal j and its structure, when
complete, is follicular, as above described. See
furthermore, for the liver of the terrestrial Gaster-
opoda, Leidy , loc. cit. Of its internal structure,
he says : u The lobuli of the liver are composed of
the rounded commencement of the biliary duct3,
and are lined with polygonal cells.” — Ed.

§ 216.

THE CEPHALOPIIORA.

245

2. With the other Cephalophora, the liver is wholly isolated, nearly always
asymmetrical, (r) and often divided into several lobes of a yellowish-brown
or brownish-green color; often, also, it wholly envelops the intestinal con-
volutions. The biliary canals, which arise from the hepatic lobes, form
usually, two, three, or more excretory ducts, which empty the bile into the
stomach or intestine, rarely into the oesophagus.®

CHAPTER VI.

CIRCULATORY SYSTEM.

§216.

For a long time it was erroneously supposed that the circulatory system
of the Cephalophora was completely closed. Rut the heart or central portion
of this system, is developed in an inverse ratio to the imperfect peripheric
part which is without a capillary net-work. This incompleteness is often
so great that, in many genera, the arteries are wanting and the veins more
or less wholly absent. 4,The circulation is, therefore, extravascular for a
longer or shorter course, and passes into cavities ( Lacunae ) situated in
the parenchyma of the body.®

The blood is colorless, often opalescent, and always very poor in corpus-
cles. These last are also colorless and consist of smooth cells, with a
granular, indistinct nucleus.®

7 With Dentalium , there are two symmetrical
livers, one on each side of the intestinal canal ; see
Deshayes, loc. cit. PI. XV. fig. 11, or Isis. Taf. YI.
fig. 15, m. m. With Diphyllidia , also, there are
two livers, one on each side of the stomach into
which they open by several transverse excretory
canals $ see MeckeVs Arch. 1826, p. 15, Taf. I.
fig. 11.

8 For the external form of the liver, consult Cu-
vier, loc. cit. The hepatic ducts open, near the
pyloric orifice, with Liman ?, Helix , Testacella ,
Doridium , and Dentalium ; into the intestine, with
Haliotis , Vermetus, Pleurobranchus, Diphylli-
dia , Doris , Planorbis , and Lymnaeus ; into the
third stomach, with Aplysia , Do/abe/fa , and JSotar-
chusj while with Onchidium , two of the ducts open
into the oesophagus, and the third into the first
stomach.*

1 The tenacity with which the opinion was enter-
tained that there is a completely-closed vascular
system with the Mollusca, is shown in the fact that
Cuvier (llegne anim. I. p. 50), after having seen,

* [ § 215, note 8.J For the details of the hepatic
structure with the Nudibranchia, see Aider and
Hancock , loc. cit. Part II. PI. II. fig. 2, e. hh.,
and fig. 3 (Dendronotus) ; Part III. PI. YIII. fig.
9 (Aeolis) y Part IY. PI. Y. fig. 1, g. g. g. ( Scyl -
laea), and fig. 8, g. g. ( Eumenis ) ; Part V. PI. I.
fig. 2, d. d., and PI. II. fig. 1, f. (Doris').

21#

with Aplysia, the veins communicate distinctly
with the cavity of the body by special orifices, still
persisted in the old view, — regarding this as an
exception ; see Mem. loc. cit. p. 13. It is only
latterly that the circulation of the blood through
the lacunae and interstices of the body, has been
shown to be the rule, by Pouchet (Recherches loc.
cit. p. 13), Milne Edwards and Valenciennes
(Compt. rend. XX. 1845, p. 261, 750, or Froriep's
neue Not. XXXIV. p. 81, 257).

Milne Edwards, in his memoir already cited
upon the circulation of Patella, Haliotis, Helix ,
Aplysia, Thetis, and Triton, has abundantly
shown that the vascular system of the Cephalo-
phora is also incomplete, and that the aorta termi-
nates in a large lacunal sinifs containing the brain,
the salivary glands, the oesophagus vv i 1 1 1 its mus-
cles, and the retracted tongue, and which fljrms also
a part of the visceral cavity •, see Ann. d. Sc. Nat.
YIII. 1847, p. 37, PI. I.-III., or Schlciden and
Froriep's Not. V. p. 1, fig. 1 — 4.

2 For the blood of the Gasteropoda, see Carus,

For the liver of Chiton, see Middendorf (Bei-
trfige zur einen Malacozoologia rossica, St. Peters-
burg, 1847, p. 63, Taf. V. fig. 2, 1.). Its ducts open
into the alimentary canal near the stomach. — Ed.

246

THE CEPHALOPHORA.

$ 217.

§ 217.

The Heart is wanting in only a few genera of the Cephalophora.® Almost
always it has a pericardium,® and is divided into a simple, very muscular
ventricle, and a thin-walled auricle which is equally simple, rarely double.®

The arterial blood passes from the respiratory organs into the auricle,
thence into the ventricle, from which it is forced through a very short aorta
over the body. These two chambers of the heart are usually pyriform, and
are joined together at their large extremity by a constriction in which is
sometimes situated a valve, which prevents the return of the blood into the
auricle.®

The position of the heart usually depends upon that of the respiratory

organs. It is generally situated at
bottom of the pulmonary cavity. It
the right side of the body.®

Von den fiusser. Lebensbeding. d. weiss-und
I 1 1 " -'Mi TIip-iv. p. 72; Ehrenberg , Uner-

kannte Struct, loc. cit. Tab. VI. fig. I. 1, II. 1
( Avion and Paludina ) ; and Erdl , De Ilelicis
algirae vasis sanguiferis. l)iss. Monacli. 1840, p.
10.

With Planorbis , the blood is red. With the
Cephalophora in general, there is only a very
small quantity of fibrine, at least there is only a
trace in the blood of Helix ; it forms a kind of a
web, scarcely visible, uniting the globules into mass-
es and rows. The nuclei of these blood-globules
become very distinct by the addition of acetic acid.*

1 Forbes (Instit. 1843, p. 358), and Darwin (Ann.
of Nat. Hist^'XIH. p. 3), have been unable to find
a heart with Sagitta ; although D'Orbigny (Vo y.
dans l’Amer. m£r., or Isis. 1839, p. 501) affirms
that he has seen the movements of this organ in
this enigmatical animal, and Darwin (loc. cit.
p. 6) has perceived a pulsating organ at the
anterior extremity of the embryos. The heart
is wanting, according to Quatrefages (loc. cit.
I.), in Zephyrina , Actaeon , and Amphorina ;
and according to Kolliker , in Flabellina , Rho-
dope, and Lissosoma. However, Souleyet
(Comp. Rend. XX. 1845, p.73) contradicts, very pos-
itively, the assertions of Quatrefages , and assigns
a heart to all the Apneusta. The difficulties in the
study of these animals, from their non-transparency,
are undoubtedly the cause of many of these contra-
dictory statements. One should not, also, conclude
as to the organization of the adults from the develop-
ment of the embryos ; for it is very singular that
the embryos of Actaeon are completely developed
without a heart ( Vogt , Comp. Rend. XXI. No. 14,
XXII. No. 9, or Froriep's neue Not. No. 795,

* [ § 216, note 2.] Ley dig (loc. cit.) describes
the blood of Paludina as containing two forms of
corpuscles; one, round, which became granular
nucleated cells after the action of acetic acid ;
the other provided on one side with processes
which disappeared upon the action of acid ; see
loc. cit. p. 170, Taf. XII. fig. 47, 48. In this con-
nection, see also for the blood-corpuscles of the
Gasteropoda ( Buccinum magnum) and their de-
velopment, Wharton Jones, Philos. Trans. 1846,
Part II. p. 96, PI. II. fig. 1-7, of the Gasteropoda
division. Jones also mentions the stellate form of
the corpuscle (fig. 4). It would appear to me that
this peculiarity is, after all, only a crenulation due

the base of the branchiae, or in the
is most often found, therefore, upon

and 820), while with the other Gasteropoda the
heart appears very early in the embryonic de-
velopment. According to Nordmann (loc. cit. p.
93), the embryos of Tergipes, which has a heart,
are developed as those of Actaeon, thus showing
that the absence of this organ in these last is only
a delay of its appearance.

Wilms (loc. cit. p. 11) has been also equally
unable to find a heart with Sagitta.

2 The pericardium is apparently wanting with
the Apneusta.

3 Chiton, Haliotis , Fissurella, and Emargi-
nula have two lateral auricles ; the last three of
these Scutibranchia resemble moreover the La-
mellibranchia in their heart being traversed by
the rectum ; see Cuvier , loc. cit., and Meckel ,
Syst. d. vergleich. Anat. V. p. 115.

4 See Cuvier, loc. cit. PI. I. fig. 2-4, II. fig. 1 ;
Carus , Erlduterungstafeln Hft. VI. Taf. II. fig. 6
{Helix) ; and Van Beneden , Exerc. zoot. loc. cit.
PI. II I. fig. 11 ( Hyalea ).

Nordmann (loc. cit. p. 26, Tab. III. fig. 4)
found with Tergipes, the auriculo-ventricular val-
vular apparatus replaced by a very movable valve
situated between the ventricle and the bulb of the
aorta. With Limax, and Arion, the valves are
wholly wanting ( Treviranus , Beobacht. aus d.
zoot. u. Phys. p. 40).

a The heart is situated on the right side of the
back, with most of the Tectibranchia, with the
dextral Pectinibranchm, and Pulmonata, and with
all the Limacina ; while it is on the opposite
side with Ancylus , Haliotis, and all the sinistral
Gasteropoda. That of Carinaria, Clio , Hyalea ,
and Cleodora, is upon the dorsal median line, a
little to the left, t

to an exosmotic passage of the cell-contents — leav-
ing the cell-membrane thus deeply wrinkled, as
may often be observed also with the blood of verte-
brates. — Ed.

t [§ 217, note 5.] With Firola , and Atlanta ,
the heart is situated near the posterior extremity
of the body ; its auricle and ventricle are com-
posed of interlaced, striated muscular fibres ; both
the auriculo-ventricular and the aorto-ventricular
orifices are valvular ; see Huxley, Ann. d. Sc. Nat.
XIV. 1850, p. 193.

See also, for the heart its positions and connec-
tions, with the Lymnaeacea, De St. Simon , Jour
de Conchol. 1852, II. p. 113. — -Ed.

§ 218.

THE CEPHALOPIIORA.

247

It lies upon the median line, and its ventricle and aorta are directed for-
wards, in those genera whose respiratory organs are symmetrical, or wholly
wanting.® With many other Cephalophora, they have also the same di-
rection, without, however, being situated on the median line ; but in the
turbinated genera, the apex of the ventricle and the aorta are directed back-
wards. *

§ 218.

The vascular system of the Cephalophora consists almost solely of arte-
ries with their branches, of large venous canals receiving the blood from
the cavity of the body, and of the lacunae in the parenchyma which return
it to the respiratory organs.

With Sagittal and some Apneusta® there are no traces of blood-ves-
sels ; and, as with the Nematodes, the nutritive liquid transudes directly
through the intestinal canal into the cavity of the body.

. In another series of the Apneusta, there are rudiments of arteries and
veins, in the form of a short aorta, which passes in front from the ventricle,
and has a bifurcated extremity, — and two vena cava even shorter, which
open each side of the posterior end of the auricle.®

With the other Cephalophora, the aorta divides, after a short course, into
two principal arteries, the anterior of which passes through the oesopha-
geal ring, and, sending branches to the cephalic organs, finally ramifies in
the fleshy walls of the body ; but the other, posterior, ramifies over the
organs in the intestinal sac. These ramifications, which sometimes form a
beautiful vascular net-work, never pass into a capillary system which

6 The heart is situated on the median line of the
back in Dentalium, Tritonia, Scyllaea , Thetis,
Phyllidia, Fissurella, and Emarginula ; upon
the posterior part of the body, with Doris, and
Chiton, as is also the case with Onchidium which
is remarkable in other respects. It is singular
that with Patella, whose respiratory apparatus is
symmetrically disposed, the position of the heart is
in front and on the right side 5 see Meckel, Syst.
d. vergleich. Anat. V. p. 119, and Arch, fiir Anat.
u. Phys. 1826, p. 19. Several of the Apneusta
have the heart on the dorsal median line, as for
examples, Tergipes ( Nordmann , loc. cit. p. 24,
Tab. II. T., Tab. III. fig. 4), Eolidina ( Quatre -
/ages, loc. cit. XIX. p. 288, PI. XI. fig. 3), Aeolis •
( Hancock and Embleton, loc. cit. PI. Y. fig. 16),
and Actaeon {Allman, loc. cit. p. 149, PI. Y.
fig. 4).

1 Krohn, loc. cit. p. 8.

Notwithstanding# the absence of a heart and a
vascular system with Sagitta, Wilms (loc. cit. p.
12), has found in the visceral cavity of these ani-
mals regular blood-currents, due, probably, to cil-
iated organs.

2 Flabellina, Lissosoma, and Rhodope , ac-
cording to Kolliker ; Zephyrina, and Amphorina,
according to Quatrefages.

3 Such a rudimentary vascular system situated
in the anterior part of the back, has been seen by
Nordmann (loc. cit. p. 24), with Tergipes, by

* f § 218, note 3.] See, for detailed remarks
against the doctrine of Phlebenterism with the Eoli-
didae, Hancock and Embleton (loc. cit. 1849).
They have shown here the existence of a pretty

Quatrefages (loc. cit. p. 288), with Eolidina, and
by Van Beneden (Instit. No. 627, or Froriep's
neue Not. No. 797, p. 68), with Aeolis.

Allman, judging from one of his figures (loc.
cit. PI. V. fig. 4, c.), has found it also with Actaeon.
Nordmann has observed, that in spite of this im-
perfection of the blood-vessels, the blood effused
into the cavity of the body circulates regularly, so
that with Tergipes , the whole body, including the
appendages, is traversed by arterial and venous
currents which can be traced eten to the two
venae cavae which arise from open mouths. This
circulation is quite like that of insects 5 except that
here, the blood of the Apneusta continues a longer
course in the arteries, for Nordmann , with Ter-
gipes, and Quatrefages, with Eolidina, have
been able to trace on each side of the body an an-
terior and posterior branch of the aorta. Quatre-
fages, however, commits an error at the outset
concerning this simple circulation of the Apneusta,
in declaring that with these Gasteropoda the rami-
fied intestinal canal serves also the function of a
vascular system 5 this has induced him to give the
name Phlebenterata to an entire group of these
animals. In the controversy between him and
Sou/eyet on this subject (Comp. Rend. XIX. XX.),
and which threatens to be interminable, this last
has gone too far in asserting that, not only with the
Apneusta, but even with all the Gasteropoda, there
is a completely-closed vascular system.*

highly-developed vascular system commencing in a
well-formed heart which consists of a ventricle and
an auricle, and enclosed in a pericardium. — Ed.

248

THE CEPHALOPHORA.

§ 219.

opens into the veins, but gradually disappear,® so that it is probable that
the blood is effused from their open extremities into the interstices of the
parenchyma of the viscera, as well as into the cavity of the body ; and is
thence taken up through numerous orifices on the inner surface of this last,
and conducted to the respiratory organs through the wall-less venous canals
which are hollowed in the muscular substance of the envelope of the
body. (5)

CHAPTER VII.

RESPIRATORY SYSTEM.

§219.

The respiratory organs are absent with only a few of the Cephalophora ;
namely : with Sagitta, the Apneusta, and with some of the Pteropoda and
Heteropoda.® With these, therefore, it may be inferred that the respira-

4 Erdl (De Iielicis algirae, &c., loc. cit.) has, in-
deed, figured venous net-works on the digestive
apparatus of an Helix (see also its copy in Carus ’
Erlauterungstafeln, Hf. VI. Tab. II. fig. 5) j but I
regard these as of an arterial nature, and this so
much the more, since Erdl, in his dissertation, has
nowhere shown a direct communication between
the arteries and veins. The absence of a capillary
net-work and of venous radicles, is quite apparent
with Arion , in which the posterior artery forms
beautiful ramifications of a white color upon the in-
testine and liver. If the larger branches of this
artery are examined, their muscular walls will be
distinctly seen to be internally lined with a granu-
lated layer composed of carbonate of lime and which
gives the color just mentioned.

If also the smaller branches are examined, their
muscular walls will be found to have gradually dis-
appeared so that the blood circulates inside of the
granular layer only 5 and this last in its turn will also
be found to have disappeared leaving no trace of
capillaries or venous radicles. For the details of
the arterial system of the Cephalophora, see the
Memoires of Van Beneden , loc. cit. (Pteropoda) 5
Milne Edwards , Ann. d. Sc. Nat. XVIII. 1824,
p. 325, PI. XI. fig. 1 ( Carinaria ), and Cuvier ,
Meckel , and Delle Chiaje, loc. cit. (Gasteropoda).

5 Although Cuvier in 1803 (Ann. du Mus. d’llist.
Nat. II. p. 299, PI. II. fig. 1, 3) perceived, on the in-
ner surface of the envelope of the body, the orifices
of the venous canals, which as a net-work traverse
the fleshy walls of Aplysia even to the base of the
branchiae, and although this was confirmed by
Treviranus (Biologie, IV. p. 238) and Delle
Chiaje (Memor. &c. I. p. 63), yet it is only lately
that the opinion has . been recognized that this
might be so with all the Cephalophora, for the ob-
servation upon Aplysia remained thus long isolat-
ed. But now, facts of this kind are so numerous as
not to be based upon exceptional observations. It
should beunderstco i, however, that the absence of
capillaries and of venous radicles, as well as the
presence of numerous orifices opening into the ve-
nous canals, are the rule with all the Cephalophora

which have respiratory organs. These orifices may
be easily seen, especially by asphyxing species of
Limax and Arion , — by which experiment, will be
appreciated the correctness of Delle Cluaje's figure
of Arion which was engraved in 1830 (Memor. loc.
cit. Tav. CIX. fig. 16 without text, and Descriz.
loc. cit. II. 1841. p. 10, Tav. XXXVII. fig. 16, the
same plate with text), with the exception that there
are orifices on their ramifications as well as on the
two principal canals. Pouchet (loc. cit. p. 19.
has named these Orifices absorbants , and his ob-
servations were also made on Arion ; but Milne
Edwards and Valenciennes (Compt.Rend. loc. cit.)
have demonstrated this structure with Aplysia ,
Doris , Polycera , Scyllaea , Patella , Chiton ,
Haliotis , No tare bus, Umbrella, Pleurobranchus .
Dolabella, Buccinum , Tritonium , Turbo , Am-
pullaria, Onchidium , Helix , &c., and therefore
with the Nudibranchia, Cyclobranchia, Scutibran-
chia, Tectibranchia, Pectinibranchia, and Pulinon-
ata. I must here repeat that these venous canals
are only lacunae excavated in the muscular
walls of the body, and are without proper walls,
as Meckel (Syst. d. vergleich. Anat. V. p. 128) has
pretended is the case with those of Aplysia. To be
convinced of their wall-less structure it is only ncc s-
sary to examine microscopically a longitudinally
incised Arion. They will be found composed wholly
of muscular fibres interlaced in every direction, and
some of which surround, sphincter-like, the venous
orifices, thus showing that these last are not closed
by valves, but by the contraction of these fibres.
Souleyet himself could not deny this wall-less struc-
ture in the veins of the Gasteropoda, although it is
in contradiction with his statements against Phle-
benterismus. He declares (Compt. liend. XX. p.
81, note 3) “ que le systthne veineux des Mollus-
ques n’est pas toujours forme par des vaisseux dis-
tincts, mais qu’il, se compose en grande partie
de ces canaux creus^s dans l’tpaisseur ou dans
l’interstice des organes.” See also below §216,
note 1.

1 Respiratory organs appear to be wholly ab-
sent in Sagitta, and Phyllirrhot.

§ 220.

THE CEPHALOPHORA.

249

tion is cutaneous, which, with the Apneusta, is probably favored by
ciliated epithelium.® With some of these species, there is an aquiferous
system which also serves, perhaps, for respiration.®

I. Branchiae.

§ 220.

With nearly all the Cephalophora, excepting the Pulmonata, there is a
Branchial apparatus; this is usually very contractile, and always covered
with very lively cilia.® It is composed either of lamellae, or of filaments
arranged in rows or in bundles, or of plumose or pectinate ramified prolon-
gations. With some, the branchiae are situated, uncovered, on the back or
on the sides of the body ; with others, they are more or less covered by the
mantle ; but with the majority, they are contained in a special cavity of
this last.

This Branchial cavity communicates externally by the Siphon, which is
simply a canaliculated, contractile prolongation of the mantle itself.®

1. With the Pteropoda, the respiratory organs are very unequally devel-
oped. In some genera, they appear wholly wanting, while in others, there
is a spacious branchial cavity containing one or two groups of fringed
lamellae from which pass out as many veins towards the auricle of the
heart.®

2. With most of the Heteropoda, there is, upon the median line of the
posterior part of the back, a pectinate or plumose branchial apparatus,
which connects with the heart by a short vein.®

3. This apparatus is most variable as to form and situation with the
Gasteropoda, and the different groups of this class are founded upon its
modifications. The Cirribranchia have a bundle of small filaments on
each side of the neck.® The Nudibranchia have on each side of the back,
in one or more rows, or in a circle upon the middle of the posterior part

2 The opinion that the dorsal and lateral append-
ages of Aeolis , Eolidina , Venilia , Zephyrina ,
Amphorina, Flabellina , Callio/mea , and Ter -
gipes , are branchiae, is untenable, since it has
been shown that they contain prolongations of the
digestive canal.

3 For the aquiferous system of Actaeon , and
Venilia , see below, § 222.

1 For the ciliated organs of the branchiae of
Gasteropoda, see Sharpey , Cyclop. Anat. &c. I.
p. 619.

2 For the branchial apparatus of the Cephalo-
phora, I must refer principally to the works of
Cuvier (Memoires, &c.), Savigny (Descript, de
l’Egypte, loc. cit. II. FI. I. -III.), Meckel (Bei-
tr&ge zur vergleich. Anat., and Syst. d. vergleich.
Anat., loc. cit.), Quoy and Gaimard (Voyage de
1’ Astrolabe, or Isis, loc. cit.), and Delle C/iiaje
(Mem. and Descriz. loc. cit.).

3 With Clio , one does not know what to think of
the form and position of their respiratory organs,
since that Eschricht (loc. cit. p. 5, 16) has shown
that the vascular net-works observed by Cuvier
upon the two fins of these animals (Mem. loc. cit.
p. 5), and which have been taken for branchial
vessels, are only muscular fibres. Van Beneden
also, could find no respiratory organs with Lima-
cina and Cuvieria. Moreover, more accurate ob-
servations are required to determine whether or not
the ibur-rayed cutaneous appendage of the poste-

rior extremity of Pneujnodermon, and the circu-
lar cutaneous lobe in the same locality with Spon-
giobranchaea , are really branchiae ; see Cuvier ,
M4m. loc. cit. p. 7, PI. B. fig 1-6, g. *, Van Bene-
den , loc. cit. p. 49, PI. I. fig. 1, d. ( Pneumoder -
rnon ) ; and D'Orbigny , Isis, 1839, p. 497, Taf. I.
fig. IX. 1-3, 11, 12 ( Spongiobranchaea ). On the
other hand, 'Van Beneden (loc. cit. p. 17, 40, PI.
I. fig. 2, 12, III. 1, 5,6) has distinctly seen bran-
chiae and branchial veins in Hyalea , Cymbulia and
Cleodora. In the first of these genera, there lie
in a very large respiratory cavity situated on the
back of the intestinal sac, numerous branchial lam-
ellae arranged in an arcuate manner, and bound
together by a branchial vein. In the other two
genera, the cavity of the mantle has, on each side,
a fan-shaped branchia. See also Delle C/iiajc,
Descriz. &c. I. p. 89, Tav. XXXIV. fig. 9, 11.

4 With Atlanta , the single branchia is simple,
pectinated, and always concealed in the interior of
their cell ( Rang , loc. cit. p. 378, PI. IX. fig. 12,
or Isis, loc. cit. p. 473, Taf. VII. fig. 12). With
Car inaria , and Pterotrachea, the branchia is also
simple, but very developed and demi pinnate, and
in the first of these genera it projects outside the
shell ( Delle Chiaje , Mem. loc. cit. Tav. XIV.
XV. LXIX., and Descriz. loc. cit. Tav. LXIII.-IV.).

5 Dentalium , according to Deshayes , loc. cit.
p. 334, PI. XV. fig. 12, or Isis, loc. cit. p. 464.
Taf. VI. fig. 16.

250

THE CEPHALOPHORA.

§ 221.

of the body, numerous fasciculated plumose, or dendritic branchiae.®
With the Cyclobranchia, and some of the Inferobranchia, the lamelli-
form branchiae are situated on the furrow which separates the border of
the mantle from the foot,® under the form of a continuous cord, or of two
lateral rows.

With the Scutibranchia, the two pectinal rows, which are wholly con-
cealed in the cavity of the mantle, have, nevertheless, a certain symmetry (8)
which is wholly absent with the other Gasteropoda. Thus, all the Tecti-
branchia have only a single lamellate or pinnate branchia situated on the
right side, rarely on the left, and which is more or less covered and some-
times wholly concealed by a fold of the mantle.® The Pectinibranchia
and Tubulibranchia have a pinnate or pectinate branchia, contained in
a cavity which is situated upon the anterior portion of the back and often
provided with a siphon on its left sided®

With many Nudibranchia, the returning blood from the branchiae is
emptied by several veins into the simple auricle of the heart, which (the
heart) is situated upon the middle line of the back.(11) With only a
few Gasteropoda, as also with the Oirribranchia, Cyclobranchia, and Scuti-
branchia, the branchial veins are united into two trunks which open into
the simple or double auricle. a2) With the other Gasteropoda, which have
an uneven, lateral branchia, (13) the blood passes from this last, through a
short, simple, venous trunk, to the heart situated near its base.

II. Lungs.

§ 221.

The pulmonary cavity, formed in the mantle of the Pulmonata, is situated

6 With Scyllaea, there are, on the back, two
pairs of cutaneous lobes, between and which are
numerous branchial vessels. WithG/awcMS, there
are, upon the sides of the body, three pairs of pro-
longations which have long, digitiform branchial
filaments. With Thetis , the back is surrounded
by a double row of semi-pinnate branchiae 5 while
with Tritonia , there is on each of its sides a single
row of multiramose branchial tufts. With Doris ,
and Polycera, there are twenty to twenty-five
more or less ramified branchiae, arranged circu-
larly around the arms, and capable, from contrac-
tion, of being withdrawn into the mantle.

7 The branchial lamellae form a complete circle
with Patella , Chiton , and Phyllidia, and two
lateral rows with Diphyllidia.

8 With Fissurella , and Emarginula , there is a
row of branchiae on each side of the cavity of the
mantle, while, with Haliotis , there are two rows
on the left side.

9 With Umbrella, Pleurobranchaea, and P /eu-
ro branc hus, this branchia, situated on the right
side and half exposed, is easily seen. On the same
side also is situated the branchial lamella often deep-
ly concealed between the folds of the mantle, of Gas-
teropteron, Aplysia , Bullaea , Notarchus , &c.
But with Doridium, the branchia is on the left
side and quite behind.

Ancylus, which differs from the other Infero-
branchia by its simple branchia, has, moreover,
this peculiarity, that this organ has the form of a
simple cutaneous enlargement on the left side, con-

* [ § 220, note 10.] See also Ley dig, loc. cit.
for the branchiae and their intimate structure,
with Paludina. According to this observer, they

cealed under a fold of the mantle ( Treviranus ,
loc. cit. p. 192, Taf. XVII. fig. 1, 2, d., or Vogt ,
loc. cit. p. 28, Taf. II. fig. 1-3, p.).

10 With Valvata, there is a single pinnate
branchia which projects out of a cavity in which it
is contained ( Gruithuisen , Nov. Act. Acad. Nat.
Cur. X. p. 441, Tab. XXXVIII. fig. 2, 3, 5, 12).
The branchia is simple and pectinate with Verme-
tus {Philippi, Enumer. Mollusc. Sicil. I. p. 169,
Tab. IX. fig. 24), Rostella, and Struthiolaria.
It is bi-pectinate with Turbo, and Janthina, and
tri-pectinate with Paludina. With many Pectini-
branchia, as, for examples, with Harpa, Cassis,
Conus , Buccinum , Terebra , Murex, Voluta,
Oliva, &c., there is, beside a very large unipecti-
nate branchia, another organ of this kind which is
smaller and bi-pectinate. The epithelium, which
covers not only the branchia, but also the walls of
the respiratory cavity, plays an important part in
the renewal of the water in the branchial cavity,
which takes place through its opening, or by the
siphon of these Gasteropoda which is situated upon
the neck usually a little to the left side.*

11 Scyllaea, Thetis , Doris.

12 Tritonia, Dentalium, Patella, Chiton,
Haliotis, Fissurella and Emarginula. Among
the Inferobranchia, Phyllidia should also be
cited here. But with Diphyllidia, on the contrary,
the veins appear to pass each into the auricle of the
heart.

13 The Tubulibranchia and Pectinibranchia.

are unipectinate with Paludina vivipara , and not
tri-pectinate, as above mentioned of this genus in
general. — Ed.

§ 222.

THE CEPIIALOPHORA.

251

at the anterior part of the back, rarely at the posterior part.® Its ori-
fice, which can be closed by a kind of sphincter, is upon the right side ; it
is upon the left with those species only which have sinistral shells, and in
one genus alone, it is upon the median line at the posterior extremity of
the body.® The pulmonary cavity is triangular with those species which
have a shell, and round with those which are without it.<3) Its interior is,
lined with a raised vascular net-work which, with the aquatic species, is
covered with a ciliated epithelium.® With the naked Gasteropoda, this
net-work forms a uniformly-meshed trellis ;® while with the others, there
may here be usually seen several large pulmonary veins, which, in passing
towards the middle principal vein, are spread over the borders of the
respiratory cavity, frequently anastomose with each other, and receive
several other veins of a dendritic form. The principal vein opens, at last,
into the auricle of the heart at the posterior corner of the pulmonary
cavity.®

Carefully examined, these veins will be found to be wall-less canals
directly surrounded by the transverse and longitudinal fibres of the man-
tle, so that, apparently, they are only a continuation of the venous canals
of the walls of the body.

III. Aquiferous System.

§ 222.

Che existence of aquiferous vessels and reservoirs, with the Cephalo-
phora, is not yet satisfactorily settled. However, it appears that here, as
with the Acephala, there is an aquiferous system with wall-less canals, of
which some are singly ramified, while others form an anastomotic net-work,
but all accompany the venous canals and open upon the surface of the
body, — presenting an arrangement analogous to the trachean system of
insects.

With some Apneusta, the existence of this system, which may have the
function of an internal respiratory apparatus, can scarcely be doubted ;

1 The respiratory cavity is situated in the middle
of the back with Parmacella , and wholly behind
with Testae alia , and Onchidium.

2 Onchidium. Whether or not the contractile,
ramified excrescences at the posterior part of
the back of this amphibious mollusk, of which
Ehrenberg has counted more than twenty, serve
really as branchiae as this naturalist asserts
(Symb. physic, animal, evertebr. Mollusca), cannot
be determined except from a most exact analysis
of these organs. TroscheL (Wiegmann's Arch.
1S45, I. p. 197, Taf. YIII.) has shown with more
certainty that Ampullaria is amphibious, for he
found a pulmonary above the branchial cavity
communicating with this last, and lined with blood-
vessels.

3 With Limax , and At ion , the respiratory cav-
ity has an annular form, its centre being occupied
by the heart and kidney.

4 I have found ciliated epithelium in the pulmo-

nary cavity of the Lymnaeacea, but not in that of
Helix or Arion.

5 Onchidium , Limax , &c. j see Cuvier , M6m.
loc. cit. PI. II. fig. 8-10 (Arion).

6 See Cuvier , Ibid. PI. I. fig. 2-4, and Trevi-
ranus , Beobacht. aus. d. Zoot. u. Physiol. Tab.
"VIII. fig. 57, 58 (Helix pomatia). In the vascu-
lar net-work which Erdl (De Helicis algirae, &c.,
fig. 6, copied in Carus , Erlauterungstafeln, Taf.
II. fig. 10) has figured with many details, all the
vascular trunks do not run towards the principal
vein, but with some their large extremity is directed
towards the border of the lungs.

This disposition, however, does not exist in na-
ture. The pulmonary vessels of this species are
arranged like those of Helix pomatia , which is
also confirmed by Van Bene den's figure of it 5 see
his Anat. de l’Helix algira, in the Ann. d. Sc.
Nat. Y. 1836, PI. X. fig. 3, f *

* [ 5 221, Dote 6.] See, for the respiratory organs of the terrestrial Gasteropoda, Lcidy, loc. cit. p.
235. — Ed.

252

THE CEPHALOPHORA.

§ 223.

for, upon the back and directly behind the heart, there is a reservoir
filled with water, from which ramifying canals pass off in all directions.®
The older observations upon these aquiferous canals of the Pteropoda,
Heteropoda, and Gasteropoda, have been but indifferently increased by
more recent labors. With these Cephalophora, the substance of the
envelope of the body is permeated by a beautiful net-work of wall-less
canals, which are filled with water, it is supposed, through several orifices
upon the surface of the body.® It is, nevertheless, far from being settled
that these canals belong to an aquiferous system, for the existence of their
external orifices is doubtful, and it may be urged that they are only a con-
tinuation of the venous system.® At all events, this question demands
further researches based upon facts observed with the Acephala and
Cephalophora.

CHAPTER VIII.

ORGANS OF SECRETION.

I. Urinary Organs.

§ 223.

With most of the Cephalophora, the Urinary apparatus consists of an urn

even, lamellate gland, which is usually

1 According to Souleyet (Corapt. Rend. XIX. p.
360, XX. p. 93), there is, with Actaeon , an aquif-
erous system, arising from a reservoir of water
situated behind the heart, and which he has called
Poche pulmonaire , which is spread through the
whole of the body. Vogt , as he has written me,
has distinctly seen this system with a canal open-
ing on the right side behind the anus. Allman
(loc. cit. p. 148, PI. V. fig. 4, a. a. b.) has also
observed it in the same species, but he took it for a
blood system. The canal, which, with Venilia ,
opens at the posterior part of the back, and which
has been taken by Alder and Hancock (loc. cit.
XIII. PI. II. fig. 1, 7, b.) for the rectum with its
anus, belongs also, perhaps, to an aquiferous sys-
tem, as well as the orifice figured by Delle Chiaje
(Descriz. loc. cit. Tav. LXXXVIII. fig. 2, d.) in
the same region, wtih Aeolis cristata ( Venilia ?).

2 Delle Chiaje is as yet the only naturalist who
has published quite detailed researches upon the
aquiferous canals of the Cephalophora indicated in
the text. In an earlier work, he has described
them with Doris , Thetis , Aplysia , Pleuro-
branchus , Pleurobranchaea , Bulla , Doridium ,
Diphyllidia , Turbo , Trochus , Nerita , Conus ,
Cypraea , Volut.a , Buccinum , Mur ex, Ceri-
t Ilium, Rostellaria , Haliotis , and Patella , as
canals which traverse the foot, opening, for the
most part, on its borders by numerous orifices (see
his Descrizione di un nuovo apparato di canali ac-
quosi scoperto negli animal i invertebrati mar ini,
in his Memor. Ac. II. p. 259, Tav. XVII. fig. 10-
15). Since then, he has described this system,
which, hj says, is wanting with the aquatic Pulmo-
n-c-.-, as a beautiful, subcutaneous net-work. He

situated near the branchial or princi-

has named it Apparato idro-pneumatico or Sis-
tema linfatico-venoso ; see his Descriz. I. p. 88,
&c., Tav. XXXII. XXXIY. XL. &c. ( Cymbulia ,
Hyalea , Carinaria , Pterotrachea , Doris , Tri-
tonia , Thetis , Pleurobranchaea , Diphyllidia ,
Doridium , Gasteropteron , Aplysia , Bulla , Si-
gar etus, and Janthina). With Cymbulia , and
Gasteropteron , this aquiferous canal communi-
cates with a large sinus from which passes off a
long afferent canal which projects from the surface
of the body (see Delle Chiaje , Descriz. loc. cit. Tav.
XXXII. fig. 1, 2, g. LY. fig. 2, b. f. 4. c. a.).

3 Meckel (Syst. d. vergleich. Anat. YI. p. 72)
positively denies the existence of an aquiferous
system and its external orifices. But he maintains
that the marine Cephalophora can absorb and re-
ject simply by their skin, considerable quantities
of water, without the need of special orifices.
Milne Edwards (Compt. llend. XX. p. 271,
or Fr or tip's neue Not. No. 733, p. 98) declares
that this apparatus, such as described by Delle
Chiaje , belongs to the venous system. I-Ie also
denies the existence of ex'ternal orifices, explain-
ing the ingress and egress of water which has
been observed with these animals, as due to endos-
mose and exosmose. Van Beneden , also (Ann. d.
Sc. Nat. IV. 1835, p. 250), says that he is convinced
that with Aplysia the so-called aquiferous canals
are only a dependence of the venous system. On
the other hand, he is inclined to admit that, with
Aplysia , and Carinaria , &c., there are small ori-
fices by means of which these animals can mix
water with their blood (Compt. Rend. XX. p. 520,
and l’Institut. No. 627, or Froriep's neue Not. No
727, p. 4, and No. 797, p. 65).

§223.

THE CEPHALOPHORA.

253

pal pulmonary vein. Its excretory duct accompanies the rectum and
often opens near the anus.®

The kidney is nearly always of a dirty yellow, or reddish color, of a
lamellated structure, and its surface is wholly without vibratile organs. It
is surrounded by a sac-like envelope which is continuous with the inter-
nally ciliated, excretory duct. Each renal lamella is composed of thickly-
‘set, delicate cells loosely bound together. In their transparent liquid floats
an obscure nucleus which, by direct light, appears brown or violet.

These nuclei, which are round and embossed, have a very dense crystalline
structure, and are undoubtedly a product of the renal secretion.® Cer-
tainly they contain the uric acid which is found when the whole gland is
chemically analyzed.® The ramified canals upon the membranous en-
velope of the kidneys, return, probably, the blood into the respiratory
organs. But in the gland itself no blood-vessel has been observed.®

With Sagitta, and the other Pteropoda, nothing like a renal organ has
yet been found. With the Heteropoda, and Apneusta, on the contrary,
there are vestiges of certain organs which further researches may show to
be of a urinary nature.®

With the Pectinibranchia, the kidney is replaced by a gland which
is situated behind the branchia, between the heart and liver, and which, in
some marine species, secretes the purple liquid.

It is composed of several ramified lamellae, and opens by a large orifice,
or by a duct of variable length which accompanies the rectum, at the base
of the branchial cavity.® With the other branchiated Gasteropoda, the
existence of this gland is yet doubtful, although with most of them, and

1 This is the gland which, with the Gasteropoda,
has been considered by the older anatomists such
as Swammerdamm , Poll, and Blumenbach , asan
organ secreting the calcareous salts, and by Cuvier
as a muciparous gland.

2 This gland corresponds, consequently, as to its
position and intimate structure, to the bodies of
Bojnnus , which, with the Lamellibranchia, have
been considered as kidneys •, excepting that they
have no ciliated organs. For the intimate struc-
ture of the kidneys of Gasteropoda, see //. Meckel ,
in Muller's Arch. 1846, p. 13, Taf. I.

3 Jacobson (Jour, de Physique, XCI. p. 318, or
Meckel's Arch. Yl. 1820, p. 370) was the first who
showed the presence of uric acid in this gland, with
Helix pomatia , and nemoralis , Li max niger,
Lymnaeus stagnalis , and Planorbis cornea.
But, Sometime previous, Ddllinger and Wohnlich
(Diss. de Helice pomatia, Wirceb. 1813, p. 23) had
regarded this organ as a kidney. The presence of
uric acid can be easily shown in the dried kidneys
of Helix pomatia and Paludina vivipara , for
when treated with nitric acid and ammonia, a con-
siderable quantity of murexid is disengaged.

4 According to Treviranus (Beobaeht. aus. d.
Anat. u. Physiol, p. 39), with Helix and Arion , a
portion of the blood of the lungs, instead of going
to the heart, passes into the kidneys, and thence
enters the great pulmonary vein. But it must be
very difficult to show the course of this liquid in
the interior of the kidneys.

5 The spongy substance mentioned by Delle
Chiaje (Descriz. II. p. 96, Tav. LXIII. fig. 3,
s.) as existing near the heart and at the base of
the branchiae, with Car inaria , is undoubtedly

a urinary gland. The long, yellow ciliated body,
but without excretory organs, which Nordrnann
(loc. cit. p. 24, Taf. II. Q.) observed with Tergipes ,
between the stomach, liver, heart and rectum, is
also, perhaps, a kidney ; at all events, as such
cannot be regarded another and neighboring body,
larger, lobulated and of a yellowish color, having
apparently an excretory canal opening externally,
and which already has been mentioned as being an
hepatic gland. Perhaps a like interpretation
should also be put upon the yellow bodies observed
by Quatrefages in the posterior part of the body
of Zephyrina , Act aeon, and Amphorina (Arm. d.
Sc. Nat. I. p. 136, PI. I\ . rig. 1-3).

6 With Tritonium , and Murex, this gland
opens by a large orifice into the cavity of the man-
tle see Eysenhardt. (. Meckel's Deutsch. Arch.
VIII. p. 216, Taf. III. fig. 4, r.), and Leiblein
(Heusinger’s Zeitsch. fur a. Organ. Phys. I. p. 4,
Taf. I. h. i., or Ann. d. Sc. Nat. XIY. 1828, p. 179,
PI. X. h. i.). A similar urinary gland has been
described with Janthina, by Delle Chiaje (De-
scriz. II. p. 108, Tav. LXVII. fig. 3, e., LXVI1I.
fig. 14, i. 1.), as an accessory respiratory cavity.
With Paludina^ this gland lias a quite long ex-
cretory duct ; see Cuvier, Mem. loc. cit. fig. 3, 1. 7,
p. q. The kidney has, moreover, been described
by Cuvier (loc. cit.), and Quoy and Gaimard
(Voy. de P Astrolabe Zool. II. or, Isis, 1834, p. 285,
1836, p. 31) under the names of Muciparous
gland. Organ of the purple, and Depurating or-
gan, with Phasianella, Turbo, Baccinum, Mi -
tra, Oliva , Capraea, Harpa, Dolium, Cassis ,
Purpura , Fusus, Auricula , &c.*

* [ § 223, note 6.J For the renal organs with Paludina , see Leydig , Ueber Paludina vivipara, &c.,
loc. cit. p. 180, Taf. XIII. fig. 49, 0. — Ei>.

22

THE CEPHALOPnORA.

254

$ 224.

especially with the Nudibranchia, and Tectibranchia, there is a glandular
apparatus which may perhaps be of this nature. (7)

With the terrestrial and aquatic Pulmonata, the lamellated kidney is quite
distinct. In the species having a shell, it is of riband-like, or triangular form,
and situated beside the heart and the large pulmonary vein. Its excretory
duct arises from the anterior extremity and passes, first, backwards to the
rectum, near the posterior corner of the gland, then turns and runs forwards
terminating, finally, in the respiratory cavity near the anus.® With the
Limacina, on the contrary, the kidney surrounds the pericardium like an
annular collar, and its excretory duct opens near the respiratory orifice.®

II. Organs of peculiar Secretions.

§ 224.

Mention has already been made of the parts of the mantle which
secrete the calcareous substance,® and further on, I shall speak of the dif-
ferent glandular appendages attached to the genital organs.®

As to the other organs of particular secretions which are less common, I
will mention the following :

O

1. With those Apneusta which have cutaneous appendages, there is, in
the dorsal and lateral lobes, a follicle whose excretory orifice opens at the
extremity of the lobe, and which secretes a granular mucous substance,
and peculiar corpuscles which resemble the nettling organs of certain
Zoophytes.®

7 With Doris , there is found between the lobes
of the liver a gland, which sends off backwards a
long excretory duct which opens externally close by
the anus and has sometimes near its extremity, a
vesicular dilatation. This gland, formerly taken
for a liver, is probably a urinary organ ; see Cu-
vier, loc. cit. p. 16, PI. I. II. ; Meckel , Beitr. zur
vergleich. Anat. I. lift. 2, p. 9, Taf. VI. fig. 3, 1.
and Delle Chiaje , Descriz. II. p. 25, Tav. XLI.
fig. 12, n. y. C. fig. 21.

The orifice found with Thetis , directly behind
the anus in the dorsal region, is also in communi-
cation with a gland which may be regarded as a
kidney 5 see Cuvier , loc. cit. fig. 1, e. and Delle
Chiaje , Descriz. II. p. 35, Tav. XLVII. fig. 1, q.,
XLIX. fig. 3. Delle Chiaje (Ibid. Tav. XLII. fig.
1, 3) has seen with Tritonia , a similar gland
opening/into the rectum ; and with Gasteropteron
(Ibid. p. 86, Tav. LIV. a.), another situated be-
tween the base of the branchiae and the heart.

The large triangular glandular mass, which, with
Aplysia , is situated in the cutaneous fold envelop-
ing the shell, and lies in the space between the
heart, the base of the branchiae and the anus, se-

* [ § 223, note 7.] See, in reference to this gland
with Doris , Alder and Hancock, loc. cit. Part V.
PI. EL. fig. 1, g. g.

For the renal organs of Chiton , see Midden-
dorff. \ loc. cit. p. 72, Taf. VI. fig. 1, N. and Taf.
VII. fig. 5, N. They consist of a velvet-looking
substance which stretches on each side of the body,
over the tendinous mass of the ventral muscles,
and join together horse-shoe-like on the anterior
border of the posterior diaphragm. Their intimate

cretes a large quantity of a red liquid ; this also is
probably a kidney ; see Cuvier , loc. cit. p. 11, PI.
II. fig. 1, C. I). E. fig. 3, B. C. D., and Delle Chi-
aje, Memor. II. p. 55, Tav. II. fig. 2, r. t. 5, 6.
With Vermetus , and Magilus , there is an analo-
gous gland behind the branchiae. However, this
renal apparatus of the branchiferous Gasteropoda
demands a more careful investigation in both an
histological and a chemical point of view.*

8 See the figures of the kidney of Helix and
Lymnaeus in Cuvier , loc. cit., and in Tr eviranus
Beobacht. &c. Tab. VIII. fig. 58 5 see also Paasch,
in Wiesmann's Arch. 1843, 1. p. 78, and, De Gas-
teropodum nonnullorum hermaphroditicorum, sys-
tem. genit. et uropoStico, Diss. Berol. 1842.

9 See Cuvier , loc. cit. PI. II. fig. 8-10, and Tre -
viranus , Beobacht. Tab. IX. fig. 59 ( Arion ), and
Paasch , loc. cit. p. 82. t

1 See § 203.

2 See below, Chapter IX.

3 These glandular follicles which, from spontane-
ous contraction can empty their contents, commu-
nicate, according to Quatrefages (Ann. d. Sc. Nat.
XIX. p. 287, 291, PL XI. fig. 5, 6), with Eolidina ,

structure consists of arborescent digitations from a
central canal. — Ed.

t [ § 223, note 9.] For the renal organ and its
intimate structure with the terrestrial Gasteropoda,
see Leidy , loc. cit. p. 239. See also for the differ-
ent varieties of this organ with this order, De St.
Simon (Jour, de Conchol. 1851, No. IV. p. 342),
who speaks of it as La Glande praecordiale. —
Ed.

§ 225.

THE CEPnALOPHORA.

255

2. The genus Aplysia has an apparatus of particular secretion, consisting
of a group of 'pyriform follicles situated under the branchia, inside of the
skin. Its excretory orifice is behind the female genital opening, and its
secretion is a whitish liquid with attributive corrosive qualities. (4)

3. Many of the Pectinibranchia, and Tubulibranchia, have upon the
upper wall of the cavity of the mantle, a row of folds which secrete an
extraordinary quantity of viscous mucus which is not excreted through any
particular duct.®

4. With several terrestrial Gasteropoda, the median line of the foot is
occupied by a straight canal lined with ciliated epithelium, which ends in
a large orifice situated under the mouth. On each side of this canal, are
rows of follicles that secrete a granular mucus which, passing into its cav-
ity, is excreted externally, probably by means of cilia.®

CHAPTER IX.

f-

ORGANS OF GENERATION.

§ 225.

The Cephalophora propagate solely by means of male and female genital

by a narrow canal, with the prolongations of the
digestive cavity which enter into the dorsal ap-
pendages, and their contained liquid is subjected to
a process of respiration. But Nordmann (loc. cit.
p. 33, Tab. II. R. R.) has been unable to find any
such communication between these two organs,
with Tergipes , and he has distinctly seen the
granular mucus which is expelled from the follicles
from contraction, escape through an orifice on the
extremity of each dorsal appendage. 'With Aeolis ,
according to Hancock and Embleton (loc. cit. p.
SO, PI. IV. V.), the product of these follicles is quite
interesting. It contains elliptical vesicles which im-
mediately burst when put in water, exposing a
transparent cylinder, out of which a filament,
sometimes of a spiral form, is projected as swift as
lightning. They compared these bodies to sperm-
atic particles ; but to me, they appear exactly like
the nettling organs of Actinia. Hancock and
Embleton have also seen and figured with Aeolis ,
a canal of communication between these follicles
and the prolongations of the digestive canal, but it
may be questioned if this was not an artificial
formation produced by compression of these organs
during the examination.*

4 See Cuvier , loc. cit. p. 4, fig. 2, £ . ; De/le
Chiaje, Memor. II. p. 56, Tav. II. fig. 2, O. fig.
3 5 and Rang , Hist. Nat. des Aplysies, p. 25.

5 These muciparous organs described by Cuvier ,
with Buccinum (Mem. loc. cit. p. 5, fig. 3, f.) as

* [ § 224, note 3.] See for further description,
together with figures of these peculiar bodies con-
taining a spiral thread, Alder and Hancock , loc.
cit. Part III. PI. VIII. fig. 14 ( Aeolis ) } they correct
their former view (mentioned above) and admit,
what I think is not in the least doubtful, that they

Feui/lcts muqueux , are also found with Mur ex
( Eysenhardt , in Meckel's Deutsch. Arch. VIII.
p. 216, Taf. III. m. m.), Terebra , Turbo , Voluta ,
Cypraea , Harpa, Dolium, Cassis , Tritonium,
&c. (Quoy and Gaimard , Voy. de l’Astrolabe, loc.
cit., or Isis. 1836, p. 35, Taf. II. fig. 6, q. Taf. III.
fig. 10, X. 18, m.). Carus (Museum Senckenberg.
II. 197, Taf. XII. fig. 8, h.) has seen similar mu-
cous folds with Magilus. With Vermetus , on the
contrary, I have found only a single, but a very
considerable, longitudinal fold which runs along
by the side of the rectum and covers the excre-
tory duct of the genital organs.

6 This muciparous apparatus of Bulimus , He-
lix, Limax , and Arion , was announced in 1829,
by Kleeberg, at the Congress of Naturalists at
Heidelberg (Isis, 1830, p. 574) ; but it had not es-
caped the observation of Delle Chiaje With many
Ilelicina and Limacina (Descriz. II. p. 10, Tav.
XXXVII. fig. 17, x.). It is therefore surprising
that it remained thus long unknown to other natu-
ralists. The assertion of Kleeberg , that with Li-
max, and Arion , the mucous canal communicates
with the venous system, I have been unable to con-
firm by observations upon Arion. Ley dig de-
clares that thi3 mucous canal with the terrestrial
Gasteropoda is the seat of the sense of smell •, see
Schleiden and Froriep's Notiz. IV. p. 24, or Ann.
of Nat. Hist. XX. p. 210.

are analogous to the nettling organs of the Polyps.
Agassiz has carefully observed them, and they
have all the characteristics of a true lasso-cell ; to
this I may add my own observations upon other
Mollusca. — Ed.

256

THE CEPHALOPHORA.

§ 225.

organs. These are either combined in one individual, or the sexes are sep-
arate. In most species there are copulatory organs. The genital organs
have several uneven divisions, which, when fully developed, are arranged
as follows : A Tuba Fallopii passes from the ovary into the uterine sao, at
whose base is an organ which secretes albumen, while at the point where it
is continuous with the vagina, there is a Receptaculum seminis. The male
genital organs consist of a testicle, a Vas deferens , and a Ductus ejaculato-
rius which opens into a retractile penis. With the hermaphroditic species,
these two kinds of genital organs are more or less blended together, — the
testicle with the ovary, and the Vas deferens with the Tuba Fallopii ; very
often also the vagina is united with the Ductus ejaculatorius, forming a
cloaca into which open several particular secreting organs. These differ-
ent male and female organs are usually lined internally with ciliated
epithelium.

The eggs of these animals have, at their escape from the ovary, a round
and sometimes an elliptical form, and are composed of a thin chorion en-
closing a finely-granular vitellus of variable color, which contains a
germinative vesicle and dot.(1) The sperm is white and opalescent, and
quite crowded with very active spermatic particles. These last are either
of the form of Cercaria , or consist of a very long filiform body, one extrem-
ity of which is incrassated and often of a spiral form. The trembling,
undulatory movements of these particles cease when placed in water, with
those species which have copulatory organs ; they become twisted into loop-
like forms and are finally rigid and motionless.®

1 See Cants , Erliluterungstafeln Eft. V. Taf. II.
fig. 4, a*. (Limaa ?), and in Muller's Arch. 1835, p.
491, Taf. XIL. tig. 2 ( Helix pomatia) ; Wagner,
in Wiesmann's Arch. 1835, I. p. 368, and Pro-
dromus, loc. cit. p. 7, Tab. I. fig. 6, 7 ( Helix and
Buccinum) ; and Allman , loc. cit. p. 152, PI. VII.
fig. 7 (Actaeon).

'■i Wagner and Erdl (Froriep's neue Notiz. No.
249, p. 98) have found with Chiton , Patella , and
Haliotis , spermatic particles of a Cercarian-form,
that is with a long body to which is abruptly at-
tached a hair-like tail. I have seen a similar form
with Vermetus gigas and triqueter. Those of
Trockus also have this form, according to Kd Hi-
ker (Beitr. loc. cit. p. 28), but the middle of their
body has a slight constriction. They are hair-like,
and taper at both extremities with Turbo , Bucci-
num. Purpura ( Kblliker , loc. cit. p. 25, Taf. I.
fig. 5), and Sagitta ( Krohn , loc. cit. p. 10, fig. 12).
With other marine Gasteropoda, as for example,
Carinaria , these particles are hair-like, but with
one of their extremities slightly incrassated {Milne
Edwards, Ann. d. Sc. Nat. XVIII. p. 324, PI. XI.
fig. 7) *, and with Doris, Tergipes, and Paludina,
this thickened extremity has a spiral form {Kblli-
ker, Beitr. loc. cit. p. 35, Taf. I. fig. 6 5 Nord-
mann, loc. cit. p. 52, Taf. III. fig. 8, 9, and my
observations in Muller's Arch. 1836, p. 240, Taf.
X.). With the pulmonate Gasteropoda, the sperm-
atic particles have only a short incrassated extrem-
ity of a spiral form ; see my observations loc. cit.
1836, p. 45, Taf. II. ; Paasch, in Wiegmann's
Arch. 1843, I. p. 71, Taf. V., and Dujardin, Ob-
serv. au Microscope, Atlas, PI: III.

The development of these spermatic particles
takes place in two large cells (Mother-cells), in
which are formed others (Daughter-cells) which are
changed into the spermatic particles. But the cell-
membrane of the mother-cell, disappears quite

* [§ 225, note 2.] My own observations on the
spermatic particles of the Cephalophora and their

early and its contents are condensed into a solid nu-
cleus around which are grouped the daughter-cells,
ultimately forming a bundle of spermatozoa. See,
beside these observations of Kblliker, Nordmann ,
and Paasch, loc. cit., those of //. Meckel, in Mul-
ler's Arch. 1844, p. 483, Taf. XIV. fig. 9-13, and
the more recent researches of Kblliker, in the Neue
Denkschrift. d. allgem. schweizer. Gesellsch. f. d.
gesammt. Naturwissensch. VIII. 1846, p. 4, Taf.
I. fig. 1-10 ( Helix pomatia).

The presence of two kinds of spermatic parti-
cles in the sperm of Paludina vivipara , is a very
remarkable fact 5 see my observations in Muller's
Arch. 1836, p. 245, Taf. X.

Beside the hair-like spermatic particles already
mentioned, there are long cylindrical bodies, from
one of the extremities of which project many deli-
cate filaments having very lively motions. These
have been described by Ehrenberg (Symbol,
physic. Anim. evertebrat. Dec. I. Phytozoa ento-
zoa, Appendix) as parasites under the name Pha-
celura paludinae.

Paasch ( Wiegmann's Arch. 1843, p. 99, Taf.
V. fig. 8), on the other hand, regards them as bun-
dles of spermatic particles of the normal form, and
Kblliker (Beitr. loc. cit. p. 63, and Neue Denkschr.
loc. cit. p. 41) considers them only as two forms
of the same kind of spermatic particle : the second
he regards as elongated mother-cells containing
many ordinary spermatic particles.

For my part, I do not know how to explain this
fact, and I would willingly place the second form
in the category of Spermatophora 5 but against this
opinion, as against that of Kblliker, and Paasch,
it can be urged that, with the second form, the ex-
tremities are never thickened or spiral, as is true
of the first, and that both forms are simultaneously
developed in the testicle.*

development, correspond closely with the above
account. Their development in special cells I have

$§ 226, 227.

TIIE CEPHALOPnORA,

257

§ 226.

Among all tbe hermaphrodite Cephalophora, the genus Sagitta stands
wholly alone, in having all parts of its genital apparatus double.

The ovaries consist of two straight, non-ciliated tubes situated at the pos-
terior extremity of the cavity of the body ; these open externally by an
arcuate oviduct, situated upon the back directly over the median line of
each of the posterior lateral fins.

The two internally ciliated testicles fill the caudal cavity, which is
divided into two chambers by a longitudinal septum. They send backwards
two short deferent canals, which open in front of the caudal fin, by two tumid
orifices, but are without copulatory organs. (1)

§ 227.

As for the other hermaphroditic Cephalophora, to which belong the
Pteropoda and a majority of the Gasteropoda, the genital organs of the
Nudibranchia, Inferobranchia, Tectibranchia, and Pulmonata, have been
the most thoroughly investigated. But the different divisions of these
organs have been interpreted in a manner so varied and contradictory, that
one can almost despair of having any positive knowledge of their rela-
tions.(1)

l See Krohn , loc. cit. p. 9, fig. 2, 7-9. The cil-
iated epithelium which covers the male genital
organs of Sagitta , from the posterior extremity to
the genital orifice, produces a general up-and-down
movement of the sperm in the testicle, a phenome-
non which Darwin has compared to the motions
of the sap in Chara (Ann. of Nat. Hist. XIII. p.
3, PI. I. tig. 1, or Froriep's neue Notiz. No. 639, p.
3, fig. 62, and Ann. d. Sc. Nat. I. 1844, p. 362,
PI. XV. B). For the genital organs of Sagitta ,
see also the researches of Wilms (loc. cit. p. 12).

1 It has been quite difficult to reconcile the fact
that, with these animals, the testicle and the ovary
are united in a single body, — the^ Hermaphrodite
gland. Cuvier , whose opinion has been followed
by Meckel , and Car us, in their different publica

observed exactly like Kolliker. I have found these
particles throughout this group, generally, to consist
of a delicate thread, one end of which is more or less
incrassated and twisted in a cork-screw manner
( JEolis , Physa , Lymnaeus , Natica , Helix , Li-
max , &c.) } in some, however, the form is remarka-
bly different. Tims, with Buccinum , it consists of a
thread with a terminal third somewhat incrassated,
but which terminates in a delicate filament. This,
as will be seen above, Kolliker has also noticed.

As to the remarkable statements made above
•JOhpon two kinds of spermatic particles with Palu-
dina vivipara , they deserve our especial attention.
My own investigations have led me to regard it as
a law in Spermatology, that each animal had only
one kind of spermatic particle, the shape and size of
which in that animal, are invariably the same *, this
point I have regarded as so well established that
I have proposed the basis of an animal classifica-
tion from spermatological data. I was therefore
surprised to find an observer like Ley dig who has
22*

tions, regarded this gland, with the Pulmonata. as
an ovary, and the albumen-secreting organ, as a
testicle. Treviranus (Zeitsch. fur Physiol. I.
p. 3. V. p. 140) was of the opposite opinion ; he
considered the hermaphrodite gland as a testi-
cle and the other as an ovary. This view has
been adopted by Prevost ( M4m. d. 1. Soc. Pliys.
de Geneve, Y. p. 119, and Ann. d. Sc. Nat. XXX.
p. 33, 43), and by Paasch (Diss. loc. cit. and
Wiegmann's Arch. 1843, 1. p. 71, 1845, I. p. 34).
In England, Rymer Jones adopts the view of Cu-
vier, and Owen that of Treviranus. IVohnlich
( loc. cit. p. 32) names as ovary, the albumen
gland ; and as testicle, the half-canal which runs
along the uterus \ but he is in doubt as to the
function of the hermaphrodite gland. Erdl , who

recently gone over the ground, according his views
with those of Siebold and others above-mentioned
(see Beitriig, loc. cit. in Siebold and Kolliker' s
Zeitsch. II. 1850, p. 125, Taf. XIII. fig. 31-43).
Ley dig, however, has watched their formation
from cells ; and here I may remark as being evi-
dence against their being spermatic particles, that,
according to him, they are produced by the meta-
morphosis of an entire nucleolated cell, and not, as
is the grand law with spermatic particles, from a
cell-nucleus. From this and from the above-men-
tioned reasons, based upon analogy, I cannot ad-
mit that these peculiar bodies are true spermatic
particles. Ley dig's observations on their develop-
ment of course render invalid the hypothesis of
Gratiolet that they are modified spermatic parti-
cles, having undergone changes, like those of the
llelicina, in the Vesicula copulatrix ; see Jour, de
Conchol. No. II. 1850, p. 116, and No. III. p.
236, PI. IX. fig. 3-7. — Ed.

258

THE CEPHALOPHORA.

§ 227.

It is only lately, that, from microscopical analyses of the contents of
these parts, this point has been made clear. A peculiarity which distin-
guishes principally the Pteropoda, Apneusta, Nudibranchia, Inferobran-
chia, Tectibranchia, and Pulmonata, is the existence of a hermaphrodite
gland. An exact knowledge of the structural relations of this gland has
been the means of reconciling the hitherto confused opinions upon the geni-
tal organs of the Cephalophora.

This gland, which is nearly always buried in the substance or the liver,
is composed of digitiform or botryoidal ramose caeca, bound together in
groups of variable size forming a lobulated organ. Upon each caecum is
an external sac, producing eggs, and an internal one, folded in the first,
producing sperm. The walls of these two invaginated follicles are usually
in direct contact, and are not separated from each other except at the
points where there are eggs which push the ovarian sac outwards and the
testicular one inwards.®

From these sacs pass off excretory canals, which, also, are invaginated,
and terminate in two principal ducts, the external of which is the
Tuba Fallopii, and the internal the Vas deferens which is usually tortuous.®

attributes to this last the function of an ovary
(Beitr. zur Anat. d. Helicinen, loc. cit.), has ex-
pressed no positive opinion as to the function of
the albumen gland. Steenstrup (Undersdgelser
over Ilermaphroditismens Tilvaerelse i Naturen,
1845, p. 76, Tab. II.) has expressed a very singu-
lar opinion on the subject of the genital organs' of
the Pulmonata. lie regards the Gasteropoda as
of separate sexes with which the different parts of
the genital apparatus are double, and that only one
side is developed, the other remaining atrophied as
in female birds. According to this, the hermaphro-
dite gland would represent the active ovary, in the
individuals which Steenstrup regards as females,
and the albumen-gland would be the ovary on the
other side imperfectly developed. The uterine canal
would belong to the active side, the Vas deferens
would be the abortive uterus on the other side, and
the penis as an abortive analogous vesicle would
correspond to the pedunculated vesicle of the active
side.

In the other individuals of the same species re-
garded by Steenstrup as males, the hermaphro-
dite gland would be the active testicle, and the al-
bumen-gland, the same organ on the other side,
abortive *, the uterus would be the developed Vas
deferens , and the proper Vas deferens the unde-
veloped organ on the other side. The pedunculated
vesicle would have the same signification as with
the female individuals, and the penis would be this
vesicle imperfectly developed.*

2 After R. Wagner (Wicgmanri’s Arch. 1836, T.
p. 370) had found in various Pulmonata, eggs and
spermatic particles at the same time in one and the
same genital gland, and I myself had expressed my
conviction (Ibid. 1837, I. p. 51) that with these
Gasteropoda the ovary and testicle were united
in a single organ, H. Meckel was the first whode-

* [§ 227, note 1.] This structure — a hermaph-
rodite gland — is not mentioned by Alder and Han-
cock in their anatomical details of the Nudi-
branchia ; see loc. cit. With those genera ( Aeolis ,
Doris , &c.) with which they have given in special
detail the generative organs, this combination of
the two sexual organs is not spoken of.

See especially Hancock and Embleto/Cs Anat-
omy of Aeolis , Ann. Nat. Ilist. I. 1848, p. 93,

scribed exactly the structure of this hermaphrodite
gland (Muller'1 s Arch. 1844, p. 483, Taf. XIV. XV).

It is, therefore, astonishing that Steenstrup
(Undersdgelser, &c., p. 76, Tab. II. fig. 3,4), who
knew the researches of Meckel , and who, judging
from his figures, saw distinctly the line of separa-
tion between the ovarian and testicular follicles,
has determined two fragments of this gland taken
from different individuals of Helix pomatiay
as being one an ovary, and the other a testicle. In
this last-mentioned fragment, he has called sperm-
atic cells not only those really such of the internal
follicle, but also the eggs contained in the external
follicle 5 while in the first-mentioned fragment, or
the so-called ovary, he has named as eggs not only
the real eggs but also the internal spermatic cells.
The spermatic particles, which he also saw at the
same time, would, according to him, be brought out
by coition.

3 Under the Pteropoda, Kolliker (Denkschrift.
&c. VIII. p. 39) has found the hermaphrodite
gland with Hyalea. From this, the organs de-
scribed by Cuvier , Eschricht , and Van lieneden ,
(loc. cit.), as ovaries and oviducts with Clio, Cym-
bulia , Cleodora , Cuvieria , Limacina , &c., may
be regarded as an hermaphrodite gland, and as
invaginated excretory canals. Under the Apneus-
ta, this gland has been seen by Kolliker , with
Aeolis , Lissosoma , and Flabellina. It exists
also with Actaeon , judging from the description
of Allmann (loc. cit. p. 152, PI. VI. VII. fig. 8)
of its voluminous and multiramose ovaries, in
which, he says there are observed, beside the pro-
jecting sacs filled with eggs, others smaller filled
with a granular substance. The first are very
probably ovarian, and the others testicular follicles.
Tergipes , also, has a similar ramified ovary ■, but
it was incorrectly interpreted by Nordmann (loc.

where the androgynous apparatus is minutely de-
scribed.

These authors affirm that although self-impreg-
nation is, perhaps, possible, yet there is usually a
congress of two individuals, and therefore a recip-
rocal copulation.

See also upon this point,— the real relations of the
hermaphrodite gland, Gratiolet , Jour.de Conchol.
1850, No. II. p. 116. — Ed.

§ 227.

THE CEPHALOPHOKA.

259

The testicular follicle and the deferent canal are lined with ciliated epithe-
lium, which, however, is wanting in the ovarian follicle.

The disposition of the various parts of the genital apparatus varies very
much according to the families and genera of these hermaphroditic Cephal-
ophora. The two invaginated excretory ducts of the hermaphrodite gland
either pass to the base of the uterus, or the Vas deferens leaves the Tula
Fallopii a little way from it, and passes in a tortuous course to the penis. (4)
In the first case, the Vas deferens leaves the Fallopian tube at the point
where it enters the uterus, and continues its course on the sides of this
organ, but as a semi-canal open upon its inner surface.®

In some genera, this semi-canal continues on along the vagina to the
genital cloaca,® while in others, it becomes a complete canal upon leaving
the uterus, and passes, after a longer or shorter course, into the penis.®
The Vas deferens has, at different points of its course, glandular or vesicular
appendages, which sometimes contain sperm. These may be compared, on
the one hand, to an Epididymis or Vesicula seminalis , and, on the other, to a
Glandula prostata.®'1

At the base of the uterus there is an Albumen-gland which is usually
tongue-shaped, and sometimes very long, being rolled up and bound together
by a cellular tissue so as to have a round form. The walls of this gland are
composed wholly of cells filled with drops of albumen which is undoubt-
edly used to envelop the eggs as they pass into the uterus.19’

cit. p. 54, Tab. II. ni. fig. 5, 0. S.). He regarded
the testicular follicles containing spermatic par-
ticles in various degrees of development, as so
many Receptacula seminis / and he attempted
to sustain this view, in erroneously supposing that
the spermatic particles could he produced in the
pouches of fecundation. As to the Heterobran-
chia, H. Meckel (loc. cit.) has found this gland
with the Nudibranchia (Doris, Tritonia , and
Thetis ), the Inferobrapchia (. Diphyllidia ), and
the Tectibranchia (Aplysia, Builaea , Doridium ,
Umbrella , Pleurobranchaea , Gasteropteron).
Kolliker (Denkschrift. loc. cit. p.40), beside confirm-
ing the existence of this gland in the marine Gas-
teropoda just mentioned, has also added the genera
Notarchus and Pleurobranchus. In the separ-
ated lobules of the ovary of a Tritonia figured by
Sars (Wiesmann's Arch. 1840, I. p. 197, Taf. V.
fig. c.), there can be easily recognized the her-
maphrodite gland, such as has been represented
with this animal by H. Meckel (loc. cit. Taf. XY.
fig. 14). According to Kolliker (Rhodope nuovo
gen. die Gasterop., in the Giornale dell1 Inst. Lomb.
di Scienze, &c., XVI. Milano, 1847, fig. 2), the tes-
ticular and ovarian follicles are grouped separately,
the one above and the others below.

4 This last case is found with Thetis , Doris ,
and Pleurobranchaea (II. Meckel , loc. cit. Taf.
XV. fig. 1, 2, 5). The Vas deferens pursues a
similar course with the Apneusta, — at least with
Flabellina , and Rhodope , according to the com-
munication from Kolliker ; and, from Allman's
(loc. cit.) figure of that of Act aeon, it may be con-
cluded that it there leaves the tube very high up
and passes to the penis.

5 Prevost was the first to point out this half-
canal (Mem. de Geneve, &c., V. p. 123, PI. I. fig.
12, II. fig. 3, and Ann. d. Sc. Nat. XXX.).

* f § 227, note 8.] This Prostate has been
well developed by Leidij (loc. cit.) with the ter-
restrial Gasteropoda. He regards it as belonging to
the male apparatus, notwithstanding its close con-
nection with the ovary, since, in Vag inulus, it emp-

0 Aplysia, and perhaps also, Builaea, Doridium,
&c. (see H. Meckel, loc. cit. Taf. XV. fig. 7).
With the Pteropoda, also, the Vas deferens does
not leave the female canal, until it reaches the
gen i fill cloaca.

7 The Pulmonata.

8 With Helix pomatia , Aplysia camelus,

Tritonia ascanii, and Diphyllidia lineata*
there is a Vesicula seminalis at the point where
the I as deferens unites with the base of the uterus
(II. Meckel, loc. cit. Taf. XIV. fig. 8, d. XV. fig.
7, d. 12, c. 10, c). It yet remains to be determined
whether the dilatation upon the common excretory
duct of the hermaphrodite gland with the Pteropo-
da, belongs to the Vas deferens or to the Fallopian
tube. In the first case it would represent an epi-
didymis or a seminal vesicle *, in the second, perhaps
an uterus j see Eschricht , loc. cit. Tab. III. fig. 25,
r.* (Clio), and Van Beneden, Exerc. zoot. loc. cit.
PI. I. et. seq. (Cymbulia, Hyalea, &c.). This Iasfi-
mentioned naturalist has simply, though errone-
ously, called this dilatation a testicle. A glandular
mass, similar to a prostate, surrounds the deferent
canal shortly after it leaves the oviduct, with Thetis ,
Pleurobranchaea (H. Meckel, loc. cit. Taf. XV.
fig. 1, h. 5, f.), Lymnaeus stagnalis (Treviranus,
Zeitsch. f. Physiol. I. Tab. III. fig. 14, ri, or Paasch,
in Wiegmann's Arch. 1843, I. Taf. V. fig. 7, i.),
Bulimus radiatus , and Physa fontinalis

(Paasch, Ibid. 1845, I. Taf. V. fig. 12 n1. 13, i.).

According to Leuckart (Zur. Morphol. u. Anat.
d. Geschleehtsorg., 1847, p. 128), the hermaphrodite
gland of the Gasteropoda has a common excretory
duct, and the eggs reach it by passing through the
walls of the testicular follicles.*'

9 This albumen-gland which formerly has been
taken, sometimes for a testicle, and sometimes for
an ovary (see above), has lately been designated

ties solely into the Vas deferens, it is composed
of tortuous, tubular, simple follicles, lined with
short, thick, pyramidal epithelia, which are
densely granular, and contain a round, nucleolated
nucleus. — Ed.

2C0

THE CEPHALOPIIORA.

§ 227

The Uterus is very often a long, large canal, with transversely plicated
glandular walls ; it is distinctly separated frem the ensuing vagina, <10) but
often, also, it is only a simple dilatation of the oviduct, <U) which is some-
times insensibly continuous with the vagina. (12) This last communicates
usually with the excretory duct of a pyriform vesicle, which, as a Recepta-
culum seminis, is filled with fresh sperm directly after the epoch of
procreation. (13) This vesicle has, moreover, sometimes a lateral, caecal
deverticulum.(14>

as a muciparous or an uterine gland. It is tongue-
shaped with nearly all the Pulmonata (see the
figures of Cuvier, Treviranus, Erdl, Paasch , &c.
loc. cit.). It is a round, glandular body with
Thetis , Tritonia, Umbrella, and Gasteropteron
( H . Meckel, loc. cit. Taf. XV. fig. 1, 12, 15, 17).
According to Kb lliker , there is with Rhodope,
and Lissosoma , a similar gland annexed to the
uterus •, and without hesitation I should pronounce
as of the same nature, the glandular body which
Allman (loc. cit. PI. VI. y.) has regarded as a tes-
ticle with Actaeon. With Doris, Aplysia, and
Diphyllidia, it is a twisted knotted tube (//. Meck-
el, loc. cit. Taf. XV. fig. 2, 7, 16).*

10 Such is the case with the Pulmonata (see the
figures of Cuvier, Treviranus, Erdl, Paasch,
&c.). Undoubtedly the glandular walls of this
uterus secrete the calcareous crystals which incrust
the eggs of many Ilelicina (see Turpin, Analyse
microscop, de 1’oeuf du limaQon, in the Ann. d. Sc.
Nat. XXV. 1832, p. 426, PI. XV.), or which supply
the gelatinous substance enveloping in the form of
a cylinder or a disc the eggs of the Lymnaeacea
(Pfeiffer, Naturg. deutsch. Land-und Sussw&sser.
Mollusken. Abth. I. Taf. VII. VIII.).

11 With the Pteropoda, the common excretory
duct of the hermaphrodite gland, before passing
into the vagina, has one or two dilatations, the
inferior of which corresponds perhaps to an uterus
( Van Beneden, Exerc. zoot. loc. cit. PI. III. fig.
18, e. IV. A. fig. 6, d. and 11. fig. 4, d. Hyalea,
Cleodora, and Cuvieria). With Clio, Cymbulia,
and Limacina, it is not yet determined whether the
dilatation which is here found belongs to the defer-
ent canal or to the oviduct, and therefore the name
of uterus cannot be given to it.

1^ The uterus is short and is directly continuous
with the vagina with the Nudibranchia, Infero-
branchia, Tectibranchia (//. Meckel, loc. cit. Taf.
XV.), and perhaps also with the Apneusta. I am
yet undecided if iu this undeveloped uterus are
formed the envelopes which, in the form of a riband,
a cord, or a capsule, surround the eggs of the N udi-
branchia, the Tectibranchia, and the Apneusta.
Thus with Aplysia, Doris , Tritonia, Aeolis , &c.,
their spawn has the form of a riband or cord *, and
with Glaucus , and Actaeon , it is wound in a
spiral manner about various objects •, while with
Tergipes, it is attached to marine plants under the
form of kidney-shaped capsules with short pedun-
cles. With Tritonia , Aeolis, and Aplysia, there
is observed the remarkable fact that there are
several vitelluses each surrounded by an albumin-
ous layer, in one and the same envelope •, see
Sars, in Wiegmanri's Arch. 1837, I. p. 402, 1840,
I. p. 196, Taf. V.-VII. 5 Van Beneden , Arm. d.
Sc. Nat. XV. 1841, p. 123, PI. I. *, and Loven, in
Isis, 1842, p. 359.

* [ § 227, note 9.] For the muciparous appa-
ratus with the Nudibranchiata, see Alder and
Hancock, loc. cit. Part II. PI. IV. fig. 15, ( Doto );
Part III. PI. VIII. fig. 2, g. g. ( Eolis ); Part IV.
PI. V. fig. 8, i. (Eumenis) ; Part V. PI. II. fig. 7,
h. h. 'Doris'); also Hancock , Ann. Nat. Hist. VIII.
1851, p. 34, PI. III. fig. 6, g. ( Antiopa ). See also

33 This Receptaculum seminis was formerly
designated under the name of pedunculated vesi-
cle ; although Treviranus regarded it as an
urinary bladder, and, with Arion , erroneously
assigned to it a communication with the kidney
(Zeitsch. f. Phys. I. p. 10). However, there can
now be no further doubt as to its nature, for if its
contents are examined shortly after coition, they, will
easily be found to consist of fresh sperm containing
fully-developed, active, spermatic particles. Later
than this, when the eggs have been deposited for a
time, the sperm will be found to have lost its fresh-
ness, and to have changed into a viscous granular
substance of a reddish or brown color, containing
sometimes traces of dead, rigid spermatic particles.
The resemblance of this matter then to excrement
is, without doubt, the reason why this organ has
been compared to an urinary bladder, or con-
founded with the sac for purple (kidney) of other
Cephalophora.

With the Pteropoda, this organ is a pyriform
vesicle with a short peduncle, — at least with Clio
( Eschricht , loc. cit. Tab. III. fig. 25, s. ), Cym-
bulia, and Limacina ( Van Beneden, Exer. zoot.
loc. cit. PI. I. fig. 17, d. V. fig. 12, A., where this
organ is figured as a sac for purple). The Ap-
nuesta, also, have a sac for fecundation ; at least I
can give no other name to a long-pedunculated,
pyriform vesicle which Nordmann (loc. cit. p. 49,
Tab. II. L., III. fig. 5, b. d.) has described as a
testicle with Tergipes ; and so much the more as
he always found perfect spermatic particles, and
not developing seminal cells.

The pedunculated vesicle with its semi-liquid
contents, which Allman (loc. cit. p. 152, PI. VI. $.)
has observed with Actaeon, is also a Receptaculum
seminis.

According to Kolliker, this organ exists also
with Flabellina, and Rhodope, as a pedunculated
vesicle communicating with the lower extremity of
the vagina. The excretory duct of this organ is
short with Thetis ( Cuvier , loc. cit. fig. 7, c. ;
Delle Chiaje, Descriz. loc. cit. Tav. XLVII. fig.
1, s.), Aplysia ( Cuvier , loc. cit. PI. IV. y 5 Delle
Chiaje, Memor. loc. cit. Tav. IV. fig. 1, p.), and
P leurobranchaea (//. Meckel, loc. cit. Taf. XV.
fig. 5, n. fig. 1, q. 7. o.). It is longer with Scyl-
laea, Bulla, Bullaea ( Cuvier , loc. cit. fig. 5, 1. fig.
10, i.), Doridium, Tritonia, Umbrella, Diphyl-
lidia (//. Meckel , loc. cit. Taf. XV.), and Notar-
chus ( Delle Chiaje, Descriz. loc. cit. Tav. LXIV.
fig. 5, n.). In the Pulmonata. this peduncle is
very long with Helix , and Clausilia ; less so, with
Lymnaeus , Planorbis, Bulirnus, and Physa,
and pretty short with Limax, Arion, and Suc-
cinea (see the figures of Cuvier, Wohnlich ,
Treviranus, Erdl, and Paasch , loc. cit.).f

14 This deverticulum exists with many Ilelicina.

De St. Simon (Observations sur l’organe de la
Glaire des Gast^ropodes terrestres et fluviatiles, in
the Jour, de Conchol. 1853, p. 1) 5 this author is
very minute in his details on the color, form and
size of this organ, with these animals. — Ed.

t [ § 227, note 13.] This receptacle is the organ
called genital bladder by Leidy , and which he

§ 227.

THE CEPIIALOPHORA.

2GI

Underneath the point of insertion of this vesicle upon the vagina, are
various glandular appendages which open into this last or into the genital
cloaca. But as yet their function is unknown. With the Pteropoda,, and
Heterobranchia, there is a single appendage only, consisting of a simple
tube.*151 To this same category belongs, also, the dart-sac, — a very remark-
able cylindrical organ opening into the genital cloaca.*16' Its walls are
quite thick, and on each side of its base is a group of more or less numer-
ous caeca.*17' At the bottom of this sac is a conical papilla which secretes
a calcareous concretion of the form of a lance-head with the point down-
wards,— the Dart. This is projected during copulation, and often remains
sticking in the skin near the genital opening. Its loss is subsequently
replaced by the secretion of another in the same place.*18'

The male copulatory organs consist of a more or less long, projecting
Penis, which, when at rest, is either retracted freely between the other
viscera of the cavity of the body, or enveloped wholly or in part in a proper
sheath ( Praeputium ).

This penis consists, nearly always, of a hollow fleshy cylinder, which is
usually closed at its posterior extremity, and has, behind, a long flagelli-

It is very long with Bulimus radiatus , Helix
arbustorum , lactea , and vermiculata ; very
short, on the other hand, with Helix pomatin ,
nem oralis, and candid issima. It is entirely
wanting with Helix fruticum , strigel/a , and
rhodostoma. With Helix algira , it communi-
cates directly with the seminal sac (see the figures
of Erdl , and Paasch). With Doris , the Recepta-
culum seminis has a peculiar structure 5 it is
kidney-shaped, and from its concavity arises a
very large excretory duct, arcuate, and opening
into the genital cloaca, which has not only a
caecal appendage, but also a short canal that
communicates with the base of the uterus (H.
Meckel , loc. cit. p. 496, Taf, XV. fig. 2). Further
research must determine if the canal which Nord-
mann (loc. cit. p. 50, Tab. Ilf. fig. 5, d.) has
observed upon the seminal sac of Tergipes with-
out being able to trace it to its extremity, is a
simple deverticulum, or a canal communicating
with the female genital organs.

15 An analogous appendix, of a round form, has
been described with Cymbulia , and Limacina , as
a prostate by Van Beneden (Exerc. zoot. loc. cit.
PI. I. fig. 17, e. V. fig. 12, B.), and as a testicle by
Eschricht, with Clio (loc. cit. Tab. III. fig. 25,
26). There is a long glandular appendix upon the
genital cloaca with Doridium, Pleurobranchaea ,
and Diphyl/idia (//. Meckel , loc. cit. Taf. XV.).
As yet the function of this gland is only hypotheti-
cal. Perhaps it furnishes the viscid substance en-
veloping the eggs during their deposition, or it may
be a copulatory pouch (Bursa cnpulatrix). But it
is quite probable that the penis enters the peduncle
of the Receptaculum seminis during copulation,
for with most Cephalophora the penis and the
peduncle are of the same length.

16 The dart-sac, which is more or less long, is
found with many species of Helix. It is absent
with Helix algira, candidissima , cellaring and
verticillus. It is double with Helix eric etor urn,

has so well figured. He found its contents to be
spermatic particles, but, in regard to its being a
seminal receptacle, he remarks: “This, however,
cannot be considered wholly as its use ; for it
secretes a mucoid matter which may probably
facilitate the passage of the ova through the vagina
and cloaca,” p. 284. — Ed.

and with Helix strigella, is replaced by two very
long coeca $ see Wohnlich, Erdl., and Paasch ,
loc. cit.

17 Two considerable groups of dichotomously
ramified caeca are found with Helix pomatia,
adspersa , austriaca , lactea , naticoides , and ver-
miculata, while with Helix umbrosa , strigel/a,
and striata , there arJonly four caeca on each side.
With Hehx incarnata , and nemoralis , there are
three, and two only with Helix lapicid x , arbus-
torum, and personata ; see Cuvier, Wohnlich ,
Erdl, Paasch, loc. cit. and Wagner , Icon. zoot.
Tab. XXX. fig. 11, 12. As to the use of these
glandular tubes, I would suggest the view that
they secrete a c mgulable substance, which, during
the coition, envelops the sperm like a spermato-
phore to conduct it into the seminal sac. Indeed,
I am much inclined to regard as the debris of a
spermat oplnre the thin h >rny bodies of a peculiar
aspect, which, with Helix hortensis , arbustorum ,
and nemoralis , often project out of the genital
cloaca after fecundation, and which, when they
have left it, are rolled in a spiral form at both ex-
tremities. When carefully examined they will be
found composed of several layers of coagulated
albumen, and to be involved in the peduncle <>f the
Receptaculum seminis ; see Huschke , in Meek-
ers Arch. 1828, p. 629, T if. VII. fig. 9, and Car us,
in Muller's Arch. 1835, p. 495, Taf, XII. fig.
4-7.

IS The dart is hollow and of the form of a cylin-
drical stylet with Helix ericetorum, and striata ;
but with Helix pomatia, hortensis, and adspersa,
four, sharp denticulated edges, extending its whole
length give it a very elegant form •, see Prevost,
in Mem. de Geneve, loc. cit. V. p. 121, PI. I. fig.
7, and Carus, in Muller's Arch. 1835, p. 494, Taf.
XII. fig. 9, 12.

It is probably an excitatory organ, for the snails
reciprocally prick each other before coition.*

* [§ 227, note 18.] For the relations of the dart-
sac with the American Helices, see Leidy, loc. cit.
lie adds, “ The dart-sac and multilid vesicles, so
common in European species, are very rare in
American species.” The dart-sac has been found
in only four species. — Ed.

262

THE CEPHALOPHORA.

§ 228.

form prolongation [Flagellum). In many of the genera of the Gastero-
poda, the Vas deferens is inserted upon the penis near its base, or at the
posterior end of its cavity. (19) The penis has also inserted into it many
small retractor muscles which arise from the walls of the envelope of the
body, or on the columella. (20)

The external orifices of these hermaphroditic genital organs are usually
on the right side, and present the following relations : 1. The vagina and
penis open into a common genital cloaca which communicates externally
upon the sides of the anterior part of the body.(21) 2. The two orifices are
situated side by side, — that of the penis directly in front of that of the
vagina. <22) 3. The orifices are quite removed from each other, and then the
penis, which is usually concealed beneath the testicle of the right side,
communicates with the genital cloaca situated behind, by a groove which
runs along the sides of the body.<23> This groove is lined with ciliated
epithelium, and, without doubt, conducts the semen from the genital cloaca
to the penis, during copulation.

§ 228.

The Cephalophora with which the sexes are separate, may be divided into
two sections, in one of which, the copulatory organs are wanting, while in
the other, they are highly developed.

1. To the first section, belong the Cyclobranchia, the Scutibranchia,
and also, probably t the Tubulibranchia and Cirribranchia ; with all of
which, the genital glands are easily seen at the epoch of procreation, from
the presence of sperm or of eggs.(1)

19 The penis is short, and of a compact form
with the Pteropoda 5 see the figures of that of
Cymbulia , Tiedemannia , Hyalea , Cleodora ,
Cuvieria , and Limacina , in Van Beneden ,
Exerc. zoot. loc. cit. Clio , however, forms an
exception in this respect, its penis being long and
flexuous ( Eschricht , loc. cit. Tab. III. fig. 24).
With the Apneusta, this organ is pretty long,
spiral-form, and concealed in a pyriform sac, and
the Vas deferens is inserted at its base ; see All-
man, loc. cit. PI. VI. t. ( Actaeon ), and Nord-
mann, loc. cit. Tab. III. fig. 5, p. q. r. ( Tergipes ).
There is a similar disposition with Thetis, Tri-
ton ia, Doris, and Pfeurobranchaea ( H . Meckel,
loc. cit. Taf. XV.). In the last-mentioned genus,
it is distinguished for its extraordinary length.
That of Arion , Limax, Succinea, Lymnaeus ,
Planorbis, Physa, Clausilia, Helix cellar ia, and
fruticum, is thick, very short, and unites either
abruptly or gradually with the Vas deferens ;
while that of Bulimus , and most species of Helix,
ends posteriorly in a long lash which projects
freely into the cavity of the body, and upon which
is inserted the deferent canal at a variable distance
from the extremity ( Wohnlich , Treviranus, Erdl. ,
Paasch , loc. cit.). With Onchidium , Bullaea,
and Gasteropteron, the penis has a very long,
flexuous lash, which, with Aplysia , and Pleuro-
branchus , is shorter, but never in connection with
the Vas deferens ( Cuvier , and H. Meckel, loc. cit.).

20 These retractor muscles are inserted at the
posterior extremity of the penis with Arion ,
Limax, and Planorbis ; and more in front and on
the sides with Lymnaeus , and Helix ( Wohnlich ,
Erdl, and Paasch , loc. cit.).

21 Such a common genital orifice is found with
Helix , Limax, Arion, Succinea, Bulimus, and
Clausilia, on the right side of the neck behind the
tentacles ; it is situated further behind, but always

on the right side, with JEolis, Tergipes , Scyllaea ,
Doris, Tritonia , Thetis, P leurobranchus, Pleu-
robranchaea, and Diphyllidia.

22 With Planorbis, and Physa, the male and
female orifices are situated on the left side of the
neck behind the tentacle j with Flabellina , Rho-
dope, Cleodora, and Cuvier a, a little further be-
hind on the right side.

23 With most of the Pteropoda (Clio, Cymbulia ,
Tiedemannia , Hyalea, and Limacina ), the orifice
of the penis is in the neck, and that of the genital
cloaca a little further behind on the right side.
With Actaeon , and Lissosoma, the two orifices
are also on the right side, but even more widely
separated from each other. With Gasteropteron,
Bulla, Bullaea, and Aplysia, the genital cloaca
is very far behind, while the penis is under the
right tentacle. With Doridium, the cloaca is also
quite in the rear, but upon the left side, and con-
sequently the penis is under the tentacle of the
same side. But with Onchidium, these orifices
are the widest apart, — the cloaca opening close by
the anus, and the penis under the right tentacle.
The furrow passing from the cloaca to the penis is
found with all these Gasteropoda, and it is very
probable that it will be found also with all the
other Cephalophora, whose penis is entirely re-
moved from the other male genital organs.

The furrow which Van Beneden (Exerc. zoot.
Fasc. II. p. 46) observed with a Hyalea , between
the two genital orifices, shows that there is such a
communication with the Pteropoda also.

1 The separation of the sexes with Chiton, Patella,
and Haliotis, was first shown by R. fVagner and
Erdl ( Froriep's neue Notiz. No. 249, 1839, p. 102).
It has been confirmed with Patella, by Milne
Edwards (Ann. d. Sc. Nat. XIII. 1840, p. 376),
and by Robin and Lebert (Ibid. V. 1846, p. 191).
With many individuals of Vermetus gigas, I have

$ 228.

THE CEPHALOPHORA.

263

•A

In the genus Chiton, the male and female genital gland is long and tab-
ulated ; it lies over the other viscera, and, from each side of its posterior
extremity, passes out a short excretory duct which opens upon the border
of the mantle.®

With Patella, and Haliotis, this gland is covered by the liver, and its
single duct passes in front and opens near the anus, at the right with the
first of these genera, and at the left with the second.®

2. In the second section, there is a protractile penis with various Hetero-
poda, all the Pectinibranchia, <4> and operculate Pulmonata.

The Ovary, or the testicle, always lies concealed at the base of the visce-
ral sac between the liver, and its excretory duct, as Tuba Fallopii or Vas
deferens , passes on to and accompanies the rectum during the remainder of
its course.

The oviduct opens near and often a little behind the anus, , and, with the
Heteropoda, has frequently several glandular appendages ; <3> while, with the
Gasteropoda, the portion accompanying the rectum is dilated into a kind
of uterine tube which has glandular walls. ® Prom the walls of this tube
are secreted, without doubt, the often very regular envelopes with which
the eggs of many Pectinibranchia are surrounded.® In this last-men-
tioned order, there has as yet very rarely been found an albumen-gland or a
receptacle of the sperm which communicates with the uterus.®

found, in the posterior region of the body, and in
the greenish-brown liver, a yellowish-brown gland-
ular body, containing active spermatic particles,
and very large caudate cells enclosing undeveloped
spermatic particles, from which passed off a long
excretory duct opening near the anus, without the
appearance of any penis. This apparatus is un-
doubtedly a male genital organ.

The other individuals, in which I could find no
spermatic particles, were the females. The details
by RiippeLL (M6m. d. 1. Soc. d’Hist. Nat. & Stras-
bourg, I. p. 3, fig. 4), and by Cams (Museum Senck-
enberg, II. p. 199, Taf. XII. fig. 8) upon the geni-
tal organs of Magilus antiquus , render probable
the separation of its sexes also 5 but it is doubtful
if the males have a penis, as Ruppell says, for it is
difficult to comprehend how copulation can take
place with this animal which lives buried in the co-
ralla of the Madreporina, any more than with the
Vermetus which are fixed upon stones. But Ca-
ms declares that he has seen, instead of a penis, an
indistinct papilla on the neck of Magilus. The
ovary, which, according to Dcshayes (loc. cit. p.
334, PI. XY. fig. 8, f., or Isis, 1832, p. 469, Taf.
VI. fig. 12, f.), fills almost entirely the cavity of the
body with Dentalium , will probably, after more
careful research, prove, with many individuals, to
be a testicle.

2 See Cuvier , Mem. loc. cit. p. 24, PI. III. fig.
10, 13, or Isis, 1819, p. 734, Taf. XI. fig. 10, 13.

3 See Cuvier , M£m. loc. cit. p. 12-18, PI. II. fig.
11, e. 14, 15, or Isis, 1819, p. 728, 731, Taf. XI. fig.
11, e. 14, 15.

4 The genus Littorina is the only one which con-
tains hermaphrodite species *, here the voluminous
penis, having a longitudinal furrow, projects under
the right tentacle ( Quay and Gaimard , Voy. de
P Astrolabe, Zool., or Isis, 1834, p. 299).

6 The genital organs of the Heteropoda are yet
little known, and what has been said in the text
relates only to Carinaria. Among the two to four
deep-colored appendages of the vagina of Carina-
ria mediterranean may be especially distinguished
a spiral tube containing internally transverse gland-
ular folds (see Delle Chiaje , Memor. II. p. 208,
Tav. XY. fig. 5, 6, and Descriz. II. p. 97.). These
appendages, the existence of which I have verified

with individuals preserved m alcohol, must be more
carefully studied before it can be decided if they
are the analogue of an uterus, seminal sac, &c.

6 See Cuvier , Mem. loc. cit. fig. 2, 3, h. Tre-
viranusn Zeitsch. f. Physiol. I. p. 32, Taf. IV. fig.
21 ; Paasch, in fViegmann's Arch. 1843, I. p. 100,
Taf. V. fig. 8 (Paludinavivipara) and Leiblein, in
Heusinger's Zeitsch. I. p. 32, Taf. I. fig. 6 (Mu-
rex). Quoy and Gaimard have furnished many
facts on this point (loc. cit., or Isis, 1S34, 1836).
With Strombus lambis , they have described a fur-
row which arises from the female genital orifice,
and passes along the right side of the foot.

7 These envelopes or capsules filled with eggs are
cylindrical, pyriform, infundibuliform, and some-
times pedunculated. They are attached singly or
in groups to objects, and sometimes are aggregated
in considerably-sized masses around a common
axis. Often they open by a special fissure, which,
in some species, has a particular operculum ; see
Lund, in Ann. d. Sc. Nat. I. 1834, p. 84, PI. VI.,
or Froriep's Not. No. 881, 882, and D'Orbigny ,
in Ann. d. Sc. Nat. XVII. 1842, p. 117. Such
a mass, arranged around an axis, in which the
eggs of Janthina are deposited, and which is
carried about with them a long time attached to
their foot, was long regarded as an enigmatical
body under the name of Spuma cartilaginea, and,
by some naturalists, has been even considered as a
modified operculum of the shell ; see Lund, loc. cit.
fig. 23 *, Lesson , in the Voy. de la Coquille. Zool.
II., or Isis, 1833, p. 134, Taf. I. fig. 1 and Delle
Chiaje , Descriz. II. p. 108, Tav. LXVII. fig. 1, 2.

8 With Paludina vivipara , there is an albumen-
gland beneath the last convolution of the intestine
(See Treviranus , loc. cit. p. 31, Taf. IV. fig. 21, u.,
and ray observations in Muller's Arch. 1836, p.
243). In this same species, the bottom of the uterus
communicates by a large orifice with a sessile Re-
ceptaculum seminis in which I have always
found, after copulation, numerous active spermatic
particles ( Muller's Arch. 1S36, p. 244). This sac
for fecundation appears to be absent with all the
other Pectinibranchia, and Berkeley (Zool. Jour.
II. 1829, p. 278, or Isis, 1830, p. 1264) could not
find it with the females of Cyclostoma.

264

THE CEPHALOPHORA.

§ 229.

The course of the seminal duct, and that of the oviduct also, is the same
as that of the uterus, until it reaches the extremity of the rectum, when
it passes into the penis which always projects from the right side of the
body. With the Heteropoda, the penis is often bifid, but then the semi-
nal canal does not traverse except one of its divisions. (9)

With the Gasteropoda, the penis is eiiher very long,(10) tongue-shaped and
often flexuous,(U) or short and lanceolate. 118 It projects under and usually
behind the right tentacle, and extends upon the side of the body — rarely
being in a wholly retracted state, but is capable of being easily folded under
the border of the mantle.

With some genera, its extremity has a small hook.(13) With several
Pectinibranchia, the seminal canal terminates behind the anus, and then
takes the form of a furrow, which communicates with the base of the penis,
extending even to its extremity, either as an external, or an internal semi-
canal.'14'

§ 229.

The development of the Cephalophora has, as yet, scarcely been observed
except with the Gasteropoda, and in particular with the Apneusta, the
Heterobranchia, and the Pulmonata.(1)

All observations concur as to the fact that the vitellus undergoes a reg-
ular and complete segmentation,! after which, there appears an usually
long, round embryo, one of the poles of which is indented and covered with

9 The penis is double and on the right side at the
base of the visceral sac, with Carinaria and Ptero-
trachea {Milne Edwards , Ann. d. Sc. Nat. XIII.
1840y p. 195, XVIII. p. 323, FI. X. fig. 3). Quay
and Gaimard (Voy. de P Astrolabe, Mollusq. FI.
XXVIII. fig. 10, or Isis, 1834, Taf. III. fig. 10)
have figured a long bifid penis with Phyllirrhoe
amboinensis ; and so, if with the other Heteropoda
the penis is not retractile, as appears to be the case
with Car inaria, according to Milne Edwards ,
this species would be a male, while Phyllirrhoe
bucephalus , figured by Ptron (Ann. du Museum
XV. tig. 1, or Kosse , De Fteropodum online.
Diss. fig. 1), apparently without a penis, would be
a female, although D'Orbigny (Voy. dans l’Amtr.
m6r., or Isis, 1839, p. 519,) regards this genus as
hermaphrodite. With Atlanta , there is a simple,
pointed penis on the right side of the neck directly
near the arms •, but as Rang (Mem. loc. cit. p.
378, PI. IX. or Isis, 1832, Taf. VII.) has found this
penis with all the individuals he has examined, it
may be questioned if the sexes are really separate
with this Heteropod.

The internal genital organs of Atlanta , and Phyl-
lirrhoe, should be thoroughly studied for the eluci-
dation of this point.*

* [§ 228, note 9.] See Gegenbauer {, Siebold and
Kolliker's Zeitsch. IV. p. 233), who has described
some follicular penis-glands with Littorina , and
which serve some purpose in the copulatory act.
— Ed.

f [ §> 229.] Upon the vitellus of various Gaster-
opoda, there appears at the time of its segmenta-
tion, a small round, colorless body, resembling a
vesicle. This was first mentioned by Pouchet
(Ann. d. Sc: Nat. 1838, X. p. 63) and has since
attracted the attention of Van Beneden in his em-
bryology of Aplysia depilans (Ann. d. Sc. Nat.
1841, XV. p. 126). Quite recently, the subject ha3

30 For the male genital organs of the Pectini-
branchia, see especially the works of Cuvier , and of
Quoy and Gaimard , loc. cit.

U Buccinum , Mur ex, Do lium, Harpa, Ampul-
lar ia, Mitra , Littorina, Strombus , Cyclostoma.

12 Janthina, Eburnea, Conus, &c.

13 Cassis, Doliurn, Buccinum, Strombus , Sig-
aretus, and Paludina. With Paludina xivipar a,
the penis is, moreover, so united to the right tenta-
cle, that this last appears to be a detached prolong-
ation from the inferior surface of its apex ( Tre -
viranus , loc. cit. Taf. IV. fig. 18).

14 With Doliurn , Harpa, Ampullaria, Tritoni-
um, Strombus, &c., this semi-canal extends even
to the end of the penis ( Quoy and Gaimard , loc.
cit.) •, while with Murex , it ceases at the base of
this organ ( Leiblein in Heusinger's Zeitsch. 1. p.
31, Taf. I.).

l With the Cephalophora, the embryonic devel-
opment does not generally begin until after the eggs
have been deposited. A few only of the Gasteropo-
da, and among them Paludina vivipara, and Clau-
silia ventricosa {Held, Isis, 1834, p. 1001), are
viviparous.

been brought up by Fred. Muller (Zur Kenntniss
des Furchungsprocesses im Schneckeneie, in Wies-
mann's Arch. 1848, p. 1) who ascribes to it a great
importance in the primitive developmental changes
of the ovum, and has called it the directive vesicle
{Vesicula directrix , or Ilichtuugsblaschen). But
the special importance of this body seems not yet
well made out, and it may be questioned if it is not
rather a secondary formation, than a primitive, di-
rective organ. See H. Rathki {Wiesmann's
Arch. 1848, p. 157) and Gegenbauer {Siebold and
Kblliker's Zeitsch. III. 1852, p. 373). — Ed.

TIIE CEPHALOTHORA.

265

§ 229.

a delicate ciliated epithelium. By the means of these cilia, the embryo
rotates upon its axis for a long time. From this period, the aquatic differ
widely from the pulmonate Gasteropoda. With the Apneusta, and the
Heterobranchia, the two lobules produced by the indentation just indi-
cated, enlarge and change into round pinions (Vela), upon whose borders
very long cilia are gradually developed. A third eminence is developed
between these two pinions, and, ultimately, changed into the foot.

Although the ciliated epithelium is always most widely spread around
these two pinions, which should be regarded as situated on the anterior
extremity of the body, yet there is formed a thin shell upon the posterior
extremity of the embryo, whether this last belongs to a conchiferous
species or not. At the same time, there appears upon the dorsal part of
the foot, an operculum corresponding as to size with the opening of the shell.

Among the internal organs, the two auditive capsules appear first; and
when these have become quite distinct, the eyes are seen. Following these,
are developed the tentacles, the border of the mantle, and the mouth which
appears between the two pinions. At the same time, the stomach, the
intestine, and the liver, individually appear in the interior. At this epoch,
the young leave the egg and swim freely about by means of the long cilia
which are situated on their extended and rigid pinions.® Subsequently
these pinions disappear, or are changed into two tentacular prominences
situated on each side of the mouth.® At the same time, also, the naked
Gasteropoda lose their shell and operculum. From the isolated facts hith-
erto published upon the embryology of other branchiferous Gasteropoda, it
may be concluded that they experience a similar metamorphosis, only the
shell of the embryo, at this time, usually presents some convolutions.®

In the development of the operculate Pulmonata, there is no analogous
metamorphosis.® The embryo lengthens a little when it begins to rotate

2 The embryology of the Apneusta, and the Ile-
terobranchia owes its progress principally to the
following works : Sars , in Wiegmann's Arch. 1837,
I. p. 402; 1840, I. p. 196, Taf.' V.-VII. 1845, I. p.
4, Taf. I. fig. 7-11 ( Tritonia , Doris , Aplysia, an 1
Aeolis) ; Lovin , in the Kongl. Vetensk. Akad.
Ilandl. 1839, p. 227, or Isis, 1842, p. 360, Taf. I.
(Aeolis); Van Beneden , Ann. d. Sc. Nat. XV.
1841, p. 123, PI. I. (Aplysia) ; Nordmann, loc. cit.
p. 71, Taf. IV. V. (Tergipes) ; Allman , loc. cit.
p. 152, PI. VII. fig. 10-12 •, Vogt, C >mpt. Rend.
XXL 1845, No. 14, XXII. No. 9, or Froriep's
neue Not. No. 795, 820 ( Actaeon ) ; and Reid , Ann.
of Nat. Hist. XVII. 1846, p. 377, PI. X. (Doris and
Polycera). Vogt has since published his entire
Memoir on the development of Actaeon viridis in
the Ann. d. Sc. Nat. VI. 1846, p. 5, PI. I.-IV. ; see
also Schleiden , and Froriep's Not. II. p. 77, fig.
1-12.

8 These remains of the two pinions are easily seen
with Tergipes , Aeolis , Doris , Tritonia , Aplysia ,
and other Heterobranchia. The ciliated lobes on the
head of Thetis , are only these pinions persisting in
an embryonic form •, see Lovin, loc. cit.

•1 According to Lovin (loc. cit. or Isis, 1842, p.
366, Taf. I. fig. 22), the young of Rissoa have a
very large pinion. Nordmann (loc. cit. p. 98) has
confirmed this, and found an analogous one with
Littorina , and Phasianella. The small Mollusks
with a pinion and a turbinated shell, of which Sars
(Beskrivel. loc. cit. p. 77, fig. 38, 39) has formed the
genus Cirropteron , have since been found by him-
self, to be young individuals of Turbo , Trochus ,
or Nerita; this accords with Grant's observations
(Edinb. new Philos. Jour. No. 13, 1827) upon Tur-

23

bo, Nerita, Buccinum , and Purpura. Judging
from Cams' figure (N ov. Act. Acad. Nat. Cur.
XIII. 1827, p. 767, Tab. XXXIV. fig. 2) of the
embryo of Paludina vivipara , it also has at tliis
age a pinion.

This remark is also applicable to the young animals
found by Lund (Ann. d. Sc. Nat. I. 1834, PI. VI.
fig. 9-14) in the egg-capsules of a Mur ex (?) and a
Natica(?). I have found, in the pyriform oviger-
ous capsules adhering to the orifice of the shell of
Vermetus, young with highly-developed pinions
having long cilia, and with a regularly convoluted
shell, such as has been described by Philippi
(fViegmann's Arch. 1839, I. p. 128, Taf. IV. fig.
8). Lovin has observed similar embryos swim-
ming with two pinions, with the Heterobranchia
of the genera Elysia, Bulla, Bullaea, and with the
Pectin ibranchia of the genera Lacuna, Cerithium ,
and Eulima ; see Arch. Skandinav. Beitr. &c. I.
1845, p. 154, Taf. I. fig. 1-8.

5 The development of the Pulmonata which have
a shell, has often fixed the attention of naturalists.
See Stiebel , loc. cit. p. 38, Tab. II. and in Meck-
el's Arch, deutsch. I. p. 423, II. p. 557, Taf. VI. 5
Hugi, Isis, 1823, p. 213 ; Cams , Von den i'tusseren
Lebensbed. loc. cit. p. 60, Taf. I. ; Prevost, Ann.
d. Sc. Nat. XXX. 1833, p. 40 (Lymnaeus) ; Pfeif-
fer, Naturg. deutsch. Lmd-und Siisswasser-Mol-
lusk. Abth. III. p. 70, Taf. I. (Helix); tyuatre-
fages, Ann. d. Sc. Nat. II. 1834, p. 107, PI. XL
B. (Lymnaeus an Planar bis) , Jacquemin, Ibid.
V. 1836, p. 117, 119, and in the Nov. Act. Acad.
&c. XVIII. 1838, ]>. 036, Tab. XLIX. L. (Planor-
bis) ; Dumortier, Nouv. Mem. de PAcad. Roy. de
Bruxelles, X. 1837, Pi. I.-IV. and Ann. d. Sc. Nat.

266

THE CEPHALOPHORA.

§ 229.

upon itself; its posterior extremity soon assumes a spiral form and is
covered with an alveolate wrapper, upon which gradually appear the
convolutions of the shell, without there being formed, at the same time,
an operculum. During this period, the eyes, tentacles, border of the
mantle, and the foot, appear at the anterior extremity ; and, in the
interior, the auditive capsules, the intestinal canal, the liver and heart
are gradually developed. Here, therefore, the development of the
cephalic pinions, which characterize the embryos of the Branchiata, is also
incomplete.

The development of the naked Pulmonata is quite different.® When
the round embryos begin to rotate, two crests appear side by side, upon
the previously divided vitellus ; one of these is changed into the shield and
into the respiratory and circulatory organs situated beneath, while the other
goes to form the foot. At its anterior extremity, appear the eyes, tenta-
cles, and lips ; and at the posterior extremity, a peculiar contractile vesicle
is formed. This vesicle presses its contents towards the vitelline substance
which is still contained in a kind of vitelline sac projecting anteriorly
between the two crests, and which, also, becomes contractile.® By this
arrangement there is an interchange of the contents of the vitelline sac and
the caudal vesicle, due to their alternate contractions. Subsequently, the
liver and digestive canal are formed out of the vitelline substance between
the two crests. The vitelline sac and caudal vesicle are in this way con-
siderably diminished, and, at last, wholly disappear.

The development of Sagitta, as far as yet known, differs essentially from
that of the Gasteropoda,® in that its embryo is not formed at the expense

VIII. 1837, p. 129, PI. III. IV ; Pouchet , Ann. d.
Sc. Nat. X. 1838, p. 63 ( Lymnaeus ) ; and Rathkd,
Froriep's neue Not. XXIV. 1842, p. 161 {Lym-
naeus , Planorbis , and Helix).

6 See Laurent , in the Ann. d. Sc. Nat. IV. 1835,
p. 248 ( Limax and Arion) ; Van Beneden , and
IVindischmann , in the Bull, de l’Acad. roy. de
Bruxelles, V. No. 5, p. 286, Ann. d. Sc. Nat. IX.
1838, p. 366, and in Muller's Arch. 1841, p. 176,
Taf. VII. VIII. {Limax)*

7 This contractility shows itself quite early in the

* [§ 229, note 6.] See also O. Schmidt (Ueber
die Entwickelung von Limax agrestis, in Muller's
Arch. 1851, p. 278) who differs in many points from
Van Beneden and IVindischmann , as to the his-
tological development of some of the organs. See,
furthermore, Gegenbaur , Siebold and Kb Hiker's
Zeitsch. III. 1852, p. 371. — Ed.

t [ § 229, note 8.] See, for some of the more re-
cent contributions to the embryology of the Cephal-
ophora, Koren and Danielssen (Bidrag til Pec-
tinibranchiernes Udvicklings liistoire, Bergen, 1851,
or its Translation into French in the Aim. d. Sc.
Nat. XVIII. 1852, p. 257, and XIX. 1853, p. 89),
and Gegenbaur (Beitrage zur Entwickelungsge-
schichte der Landgastropoden, in Siebold and Kbl-
liker's Zeitsch. III. 1852, p. 371.) These works are
quite complete as far as they go, and that of Ge-
genbaur, especially, has full details upon the form-
ation of all the organs and their mutual embryolog-
ical relations. No just r£sum£ can be given in the
proscribed limits of my notes.

I cannot here well omit at least an allusion to that

vitellus of the Limacina, for Dujardin (Ann. d. Sc.
Nat. V 11.1837, p. 374, or, Observ. au Microsc. Atlas,
1842, PI. V. fig. 10, 11) has seen in the eggs of Li-
max cinereus soon after their deposition, singular
vitelline movements exactly resembling the alter-
nate protrusions and retractions of the parenchyma
of Amoeba.

8 See the observations of Darwin , in the Ann.
of Nat. Ilist. XIII. p. 4, or Aim. d. Sc. Nat. I.
1844, p. 363. t

most remarkable episode in the embryology of the
Mollusca, the development of certain Mollusks in
Ilolothurio'idea. The facts of the case were discov-
ered and announced by J. Muller (V erliandl. der
Akad. zu Berlin, 1851, p. 628 (October 23), and
Naclitrag, p. 679 (Nov. 13), or in extenso in Mul-
ler's Arch, 1852, p. 1), and they are indeed so
wonderful that it is well they were first brought out
by so reliable a physiologist and embryologist.

The main facts, briefly stated, are as follows : In
certain individuals of Synapta digitata there are
found from one to three sac-like bodies in the cavity
of the body, and attached by their superior extremity
to the head, and by the lower end to the intestific ;
but this connection of the sac with the abdominal
and other organs, is one of simple contiguity and
not of very direct communication. The upper por-
tion of the sac is of a yellow, and the lower of a
green color *, the lower portion, moreover, ie intus-
suscepted, with a blind end, like an inverted finger
of a glove. It is in this sac-like organ that are de-
veloped true Mollusks ; in the upper or more ca-

§ 229.

THE CEPHALOPHORA.

267

of the entire surface of the vitellus, but surrounds the last in a ring-like
manner, and is gradually detached by its cephalic and caudal extremities.

pacious portion are found both male, (testes), and fe-
male (ovarium) organs in the shape of sacs, which
are not attached in any way to the main molluskig-
erous sac. These genital organs bear no resem-
blance whatever to ordinary testes or ovaria, except
in their products, which are identical. When the
ovarium is perfectly developed, it and its capsule
burst and discharge the ova which are then con-
tained in the main molluskigerous sac ; after this,
fifteen to twenty ova become invested with a com-
mon capsule, though their fecundation takes place
previous to this investment. Upon this succeeds
their development.

The sperm- capsules vary from four to eighteen in
number, and lie perfectly free in the main sac, not
far from the ovary. The spermatic particles are
set free by the bursting of these capsules, and they
resemble thos.e of the Gasteropod Mollusks in shape
and form.

The development in the egg here proceeds exact-
ly as with the Mollusca(e. g. Actaeon , according to
Vogt), and finally it assumes pretty definite char-
acters indicating rather its relation to the Pectini-
branchia. Of its zoological character as a Mol-
lusk there can, therefore, be no doubt, and the whole
story in a word is, that a true Mollusk is developed
within a Synapta , not by gemmation, but by
means of the normal sexual products which occur
under otherwise amorphous and anomalous parts
and conditions. It should, moreover, be remarked
that the connection of this molluskigerous sac is
not special or direct with the Synapta , but this last
appears to serve as a kind of nest in which the
Mollusk carries out its ulterior and remarkable
changes.

Such being the facts, the question now arises,
What interpretation shall be given these phenome-
na ? The distinct sexual mode of reproduction
would seem to remove these phenomena from the
category of the so-called alternation of Generation,
or gemmiparity as we now understand it. Then
again, the doctrine of “ heterogeneous generation ”
as suggested by Muller, does not seem to me ad-
missible, beside being particularly unsound, — for
if an animal can produce, by true sexual generation,
an offspring zoologically dissimilar to itself, zoolo-
gists may well look about for the stability of their
science. If I may be allowed an opinion or rather
a view on a subject on which I have made no ob-
servations, I would say that an approximate solu-
tion of this enigma seems obtained by admitting the
possibility of new and hitherto unknown parasitic
conditions in the life of the Mollusk in question.

Why may not this Mollusk undergo a form of
retrograde metamorphosis during which its life is
parasitic and very peculiarly connected with the life
of another and wholly different animal ? Or again,
why may not the phenomena observed be the final
conditions of certain low modes of life which are
connected with points iu the economy of these
animals that we do not yet understand ? I throw
out these remarks in a suggestive way. If we re-
fer for a moment to the historical relations of the
Cestodes, it will be perceived that there was a time
when the conditions of their life were equally if not
more obscure. Siebofd, however, has shown that
here, although the path taken by Nature is circuit-
ous and intricate, yet, after all, no new features of
a heterogeneous nature are introduced, and that
all required for the observer was cave and pa-
tience. It does not seem to me any more im-
probable that this Mollusk should have entered in
some of its stages the body of the Synapta, since
the anomalous undeveloped forms of many Hel-
minthes pursue a similar course. Let the natural-
ist also bear in mind the remarkable phenomena of
the Hectocotyli. In the Nachtrag to this first ac-
count before the Berlin Academy, but more espec-
ially in a subsequent and more complete account
(Ueber die Erzeugung von Schnecken in Holothu-
rien, in Muller's Arch. 1852, p. 1) lately given,
Muller discusses still further these facts. After
some remarks upon the importance of a careful
study of the embryology of this curious form, he
says : “Ido not give up the hope that we may yet
determine at least the genus of this Mollusk ; and I
found this hope mainly upon the very characteris-
tic form of the spermatic particles, bec-ide the other
features above mentioned The sperm-

atic jmrticles of Natica and its allies are yet un-
known In studies bearing upon this mat-

ter, one should particularly bear in mind the ter-
minal enlargement of the spermatic particles, which
up to this time has been observed in no Gasteropod,
but which with the spermatic particles of the Mol-
lusk in question is never wanting.” Although for
some time familiar with the details of the spermatic
particles of the Gasteropod Mollusks, yet I have
very recently reexamined the spermatic particles
of Natica {N. her os) with reference to this point.
They resemble closely those of the pulmonary Gas-
teropoda {Helix, for instance), and consist of a well-
defined cork-screw head to which is attached a
very delicate tail *, they agree, therefore, in general
with the form given by Muller of the Mollusk in
question. — Ed.

BOOK ELEVENTH.

CEPHALOPODA.

CLASSIFICATION.

§ 230.

The Cephalopoda present, in their organization both internal arid
external, so many peculiarities which distinguish them from all the other
Mollusca, that it is necessary to consider them in a class by themselves,
although their genera are not numerous.

It is, moreover, necessary to state why we here regard the different forms
of Hectocot ylus which hitherto have been considered as parasites of these ani-
mals, as the males of certain Octopoda.® The researches of KdlliJcer have
led us to make this change. This naturalist founds his opinion upon the
following convincing reasons:® The specimens of Hectocotylus have bran-
chiae, and a heart with arteries and veins, and they cannot, therefore, be
regarded as Helminthes. On the other hand, they have, in common with the
Cephalopoda, the contractile chromatophoric cells of the skin, and the same
kind of spermatic particles and suckers ; and the muscular substance of
their body is arranged exactly like that of the arms of the Cephalopoda.
All of them are males, and the Cephalopoda, with which they are connected,
are all females ; finally, the embryos found in the eggs of certain Octopoda
exactly resemble them. Whoever has had the opportunity of examining the
species yet known, viz : Hectocotylus argonautae , octopodis, apd tremoctopo-

1 At present there are known two or three species
of these singular beings resembling the torn-off
arms of the Octopoda, and which live in the cavity
of the mantle of certain Octopoda, attached by
the means of suckers. Hectocotylus argonautae
was first described quite imperfectly by Delie C/ii-
aje (Memor. &c. II. p. 225, Tav. XVI. fig. 1, 2,
and Isis, 1832, Taf. X. tig. 12, a. b.) under
the name of Trichocephalus acetabularis. An-
other description by Costa (Ann. de Sc. Nat.
XVI. 1811, p. 181, HI. XIII. fig. 2, a.-c.) has not
added much to our knowledge of the real nature of
this animal. Another species, Hectocotylus orto-
podis , established by Cuvier (Ann. d. Sc. Nat.

XVIII. 1829, p. 117, PI. XI. A. fig. 1 5, or Fro-
riep's Not. XXVII. 1830, p. 6, fig. 16-19, or Isis,
1832, p. 559, Taf. IX. fig. 1-5) should be found in
the cavity of the mantle of Octopus zranulatus
{Lamarck). It is probably identical with Octopus
tuberculatus of Delle Chiaje ( Octopus Verany ,
tf'agner), which lives in the Mediterranean Sea,
and perhaps, also, with Tremoctopus violaceus.
If tin's last is not so, there is then a third species
of Hectocotylus , viz : the male of Tremoctopus
violaceus.

2 See Kolliker , On the Hectocotylus of Tre-
moctopus violaceus , and Argonauta argot in
the Ann. of Nat. Hist. XVI. 1815, p. 111.

§ 230.

TIIE CEPHALOPODA.

2G9

*

dis, as well as the females on which they are found, will admit the cor-
rectness of the preceding statement, and, also, must have perceived the very
remarkable abortiveness of the males of Argonauta and Tremoctopus .<3)

Family: Nautilina.

Genera : Nautilus , Spirula.

Family : Octopoda.

Genera : Ar gonauta, Tremoctopus, Octopus, Eledone.

Family : Loligina.

Genera : Sepia, Loligo, Onychoteuthis, Sepioteuthis, Ommastrephes. Loli-
gopsis (Perot his), Cranchia , Rossia, Sepiola.

BIBLIOGRAPHY.

Swammerdamm. Zergliederung der spanischen Seelcatze (Sepiae mariss,
in the Bibel der Natur. Leipzig, 1752, p. 346, Taf. L.-LII.

Needham. An Account of some new Microscopical Discoveries. Lon-
don, 1745, or the same in French. Leide, 1747. It contains the anatomy
of Loligo vulgaris.

Cuvier. Memoire sur les Cephalopodes et leur Anatomie, in the Mem.
sur les Mollusques, loc. cit. PI. I.— IV.

Brandt. Medizin.Zool. II. p. 298, Taf XXXI.-II.

Owen. Memoir on the pearly Nautilus. London, 1832 (in the Isis,
1835, p. 1, or in the Ann. d. Sc. Nat. 1833, XXVIII. p. 87). Also
description of some new and rare Cephalopoda, in the Trans, of the Zool.
Soc. II. 1841, p. 103; and the Art. Cephalopoda, in the Cyclopaedia of
Anatomy, I. p. 517 ; also the twenty-third of the Hunterian Lectures, on
Cephalopods with chambered shells, 1843.

Grant. On the structure and characters of Loligopsis, in the Trans, of
the Zool. Soc. I. 1835, p. 21, PI. II. ; also on the Anatomy of the Sepiola
vulgaris, Ibid. p. 77, PI. XL (in Isis, 1836, p. 389, Taf. X. fig. 4—10).

Rathke. Perothis, ein neues Genus der Cephalopoden, in the Mem.
presentes a l’Acad. imper. de St. Petersberg, II. 1835, p. 149, Taf. I. II.

Van Beneden. Mem. sur PArgonaute, in the Nouv. Mem. de l’Acad.
Roy. des Sc. et belles-lettres de Bruxelles, XI. 1838, or in the Exer. zoot.
Fasc. I. 1839, PI. I.-V.

Ferussac and D'Orbigny. Hist. nat. gen. et particuliere des Mol-
lusques. Cephalopodes acetabuliferes. Paris, 1834.

Valenciennes. Nouv. Recherch. sur le Nautile flambe, in the Arch, du
Museum d’hist. nat. II. 1841, PI. VIII.— XI.

Kolliker. Entwickelungsgeschichte der Cephalopoden. Zurich, 1844.

•3 I am indebted to Kolliker for the examination have been preserved in alcohol a long time, yet I
of these individuals of Hectocotylus tremocto- was able to assure myself of the correctness of
podis , of which I found two in one and the same many of Ko/liker's statements, and thereby to be
cavity of the mantle of a female. Although they convinced of the real nature of these animals.*

[ § 230, note 3-1 See my note below under § 2G1, note 6. — Ed.

23*

270

THE CEPHALOPODA.

§§ 231, 232.

*

ADDITIONAL BIBLIOGRAPHY.

Reinhardt and Prasch. Om Sciadephorus Miilleri en Nudersogelse.
Kjbbenhavn, 1846, mit 5 Tafeln.

Prasch. Nogle nye Cephalopoder, beskrevne og anatomist undersogte.
(From the Mem. of the Danish Academy 5th ser. I.) Kjobenhavn, 1847.

Milne Edwards, Regne animal, ed. illustr. Mollusques, PI. 1'. lb. 1 .
3d. le. lf. (Octopus). — Ed.

CHAPTER I.

INTERNAL SKELETON.

§ 231.

The Cephalopoda have many cartilages, which, serving as points of inser-
tion for muscles, and surrounding the nervous centres, may therefore
be regarded as the rudiments of an internal skeleton.

Their texture is essentially the same as that of the true cartilages of the
vertebrata. There is a homogeneous, usually yellowish base, having the
aspect of ground glass, in which are scattered numerous dark-colored mole-
cules. This base contains, moreover, the proper cartilage cavities, which
enclose a mass of granules, and each a more or less distinct nucleus. These
cavities are more or less numerous, and are often partitioned each into two
by a thin septum.

§ 232.

These rudiments of an internal skeleton may be divided into the
cephalic, dorsal, articular, branchial, and pinnate cartilages.®

1. The Cephalic cartilage is concave in front and convex behind. It
is perforated in the centre by the oesophagus and by two lateral conchoidal
prolongations. At its upper part there is a deep excavation for the
reception of the brain ; and, at the inferior part, an enlargement containing
the auditive oigans. It is, moreover, traversed by canals of different sizes
for the passage of nerves. The two lateral prolongations cover, by their
anterior and concave surface, the ocular bulbs, and are thus the analogues
of a kind of orbits. With Loligo, and Sepia, there are, beside, two lanceo-
late, cartilaginous lamellae, which join with the anterior and inferior parts
of the cartilage, covering the ocular bulb in front, and thus completing the
orbit. Nautilus differs very much from the other Cephalopoda in this
respect. The lateral prolongations are wanting, and the body, which is
incomplete above, is much developed below, and has two prolongations
extending in front in a forked manner and concealing the auditory
organs.®

1 For the different cartilages, see. Schultze , in
Meckel's deutsch. Arch. IY. p. 334, Taf. IY. fig.
1, A-G *, Spix, Cephalogenesis, p. 33, Taf. V. fig.
15-17 \ Meckel , Syst. d. vergleich. Anat. II. Abth.
1. p. 125 ; Brandt , Medizin Zool. II. p. 303, Tab.
XXXII. j Owen , Cyclop. Anat. and Phys. I. p.
524, fig. 212, A-D *, f Vagner , Icon. zoot. Tab.

XXIX. j and Van Beneden , loc. cit. PI. I. ( Argo -
nauta).

2 See Owen , On the Nautilus, p. 16, PI. YIII. fig.
1, or Isis. 1835, p. 14, or Ann. d. Sc. Nat. XXVIII.
p, 102, PI. IV. fig. 1, and Valenciennes , loc. cit.
p. 271, PI. IX. fig. 4-0.

$ 233.

THE CEPHALOPODA.

271

2. The Dorsal cartilages are found only with Sepia and Loligo. They
are two in number ; the inferior is situated in the neck, and the superior
in the mantle at the anterior extremity of the internal shell. The cervical
cartilage of Loligo is very long, rhomboid, and pretty massive ; while that
of Sepia consists of a thin, semilunar plate, with the cavity directed back-
wards. In both genera, its median line has a longitudinal groove ; and in
both also, the superior cartilage is only a thin semi-lunar lamella, both
extremities of which are extended backwards by a long prolongation.

3. Those are called Articular cartilages, which, with Argonauta, and
the Loligina, are found on each side of the base of the funnel, in the form
of long cupels whose cavities receive, when the mantle is closed, the two
cartilaginous prominences of its (the mantle’s) internal surface.®

4. The Brachial cartilage is found only with Sepia. It is a narrow
plate, transversely situated directly in front of the superior border of the
cephalic cartilage. It has, anteriorly, three short apophyses for the support
of the base of the arms. With the Loligina, there is found in the mantle,
at the base of the lateral fins of the body, two other narrow lamellae, —
the Fin-cartilages ; these serve as points of insertion of the muscles of the
fins, and extend more or less along the sides of the body, taking the form
of the fins.®

CHAPTER II.

CUTANEOUS ENVELOPE.

§ 233.

The Cephalopoda are distinguished from the other Mollusca by a wholly
peculiar structure of their skin. The skin is easily detached from the sub-
jacent muscular layer, to which it is united by a loose cellular tissue, the
fibres of which are interlaced in every direction. The extremely thin
epithelium of the skin is lamellated, but never ciliated, with the adult indi-
viduals. The Corium is composed of a contractile fibrous tissue, in the
meshes of which are contained the remarkable contractile Chromatophoric
cells. ® These consist of flattened, contractile cavities surrounded by a very

3 See the figures of Fdrussac , loc. cit. (Sepia,
Sepiola , and Argonauta). With Argonauta , the
two projections of the mantle are round tubercles,
while with Loligo, Onychoteuthis , and Sepiola,
they are two very long longitudinal ridges, to
which corresponds a groove-like excavation in the
two oppositely situated cartilages of the funnel.

By means of these articular cartilages, together
with the two dorsal, when present, the collar-like
border of the mantle is exactly fitted about the neck
of the Cephalopoda.

4 The cartilages of the fins are very long with
Sepia (Schultze, loc. cit. fig. C. I)., and Owen,

* [ § 233, note 1.] I have made some careful ob-
servations with the microscope upon the chromatic
relations of the skin of the Cephalopoda, selecting for

Cyclop. &c. fig. 212, D. I).), but very short with
Sepiola.

l For the chromatic cells, see San Giovann i , in
the Giornale enciclopedico di Napoli Ann. XIII.
No. 9, or Froriep's Not. Y. 1823, p. 215, or Ann.
d. Sc. Nat. XVI. 3829, p. 308 ; Frenage, Observ.
sur la mobility des taches que l’on remarque sur la
peau des Calmars, &c., Paris, 1823 ■, Delle Chiaje ,
Memor. &c. IV. 1829, p. 63, and Descriz. I. 1841,
p. 14 ; fVagner, Isis, 1833, p. 159, in Wiegmann's
Arch. 1841, I. p. 35, and Icon. zoot. Tab. XXIX.
fig. 8-13, and Harless, in fViegmann's Arch.
1846, I. p. 34, Taf. I.*

my subject the common Squid ( Logligo illicebrosa).
My results differ somewhat from those of Harless
above-mentioned. I found only one kind of pig-

272

THE CEPHALOPODA.

§ 234.

delicate elastic membrane ; when contracted, their form is round, but it
becomes dentate on dilatation. The pigment granules, which thej enclose,
are always of the same color in each cell, and produce the red, the yellow-
ish-brown, the blue, or violet spots, whose extent and shade vary, accord-
ing as the cells are contracted or dilated.® Usually, adjacent cells have
very different colors, and to their alternate contractions and dilatations in
groups, are due those magnificent chromatic changes which have long made
celebrated the skin of the Cephalopoda.®

These contractions, and consequently these chromatic changes, are under
the influence of the nervous system. This is the reason of their decrease
or disappearance, or their reappearance and increased brilliancy, in certain
places, when the neighboring or even the distant skin is irritated. More-
over, the fibres of the corium preserve their contractility after having been
detached, so that the chromatic changes may be observed on portions of
the skin that have been removed.

§ 234.

Behind the neck of the Cephalopoda, the skin forms a large sac-like
mantle, which completely envelopes the trunk, but is adherent only upon
the back. Its anterior border is free, and can embrace, like a sphincter, the
neck and posterior part of the head. Under the throat, the skin is pro-
longed in the form of a funnel , the free apex of which extends in front,
while the broad base communicates with the cavity of the mantle, and is

2 The jpovements of the chromatic cells are not
directly due to the cell-membrane, but to the con-
tractile fibres of the dermis which are united in
them, and which, upon contraction, pull at their
point of insertion, thus producing the ragged as-
pect of these cells when expanded. They return to
their round form when the fibres are relaxed, from
the elasticity of the cell-walls (see Kolliker , Ent-
wick. d. Cephalopoden, p. 71, and Harless , loc. cit.).
When these cells are dilated, the pigment granules
are often removed from the centre to the periphevy
of the cell, thus forming a central, colorless trans-
parent spot, which has been regarded by Wagner
(loc. cit.) as the nucleus of the cell.

3 These so highly characteristic chromatic cells
of the Cephalopoda, are found also in the skin of
Hectocotylus, and are, therefore, one of the data
for determining the nature of these animals, which
have hitherto been regarded as trematode parasites.
Delle Chiaje and Costa (loc. cit.) have repre-
sented these cells in a colored figure of Hecto-
cotylas argonautae. I have, also, distinctly seen
them with individuals of Hectocotylus tremoc-
topodis preserved in alcohol.

As Grube (Aktinien, Echinodermen und W fir-
mer des Adriat. und Mittel-Meeres, p. 49, fig. 2)
has observed these same chromatic cells in the skin

ment, deposited, as he has so well described, in the
chromatophoric contractile sacs. The splendid
changeable colors of the surface appeared to be
due, not to the pigment spots alone, but to the in-
tervening tissue ; and the surface color over the
pigment spots is subject to the same variations.
Thus, a bistre-brown spot will sometimes appear
blue, then green, &c. These facts may be tested
by placing a small portion of the skin on a plate of

of a genus of parasites, which he has cnlled Poly -
porus chamaeleon , it is certain that this animal,
found on the branchiae of a marine fish, is only a
torn off arm of one of the Loligina. The presence
of these cells in the skin of Nautilus seems proved,
for Rumpk (Amboinische Raritaten-Kammer von
Sohnecken und Muscheln, p. 7) expressly declares
of this animal which he saw living, that “ its upper
portion is reddish or bright brown with some black
spots, which, as with the cuttle-fish, become faded.”

The fragment of the Mollusk, which Quay and
Guimard found at the Celebes islands, and which
they thought to belong to Nautilus pompilius
(Ann. d. Sc. Nat. XX. 1830, p. 470, PI. XIV.
A. or Isis, 1834, p. 1146, Taf. XV. A. B.)
deserves our attention in various ways. If it
really belonged to a Cephalopod, it should have the
chromatic cells, a point which may yet, perhaps, be
determined from the preserved specimen at Paris.

In the colored figure which these naturalists have
given of it, the skin is dotted with red, — a presump-
tion in favor of the existence of these cells.

But, indeed, is it not possible that this animal,
from its resemblance to the Hectocotyli, is not a
mutilated one, but the male of Nautilus pompiliuSy
abortive as to its form and size ?

glass, and introducing a little w'ater under it, the
evaporation of which, by changing the surface con-
ditions, generally produces a variety of colors.

The chromatic appearances of these animals ap-
peared to me, therefore, as due full as much to sur-
face phenomena as to pigment , and I have failed
to detect different layers of pigment as described by
Oiven ; see Burnett , Proceed. Bost. Soc. Nat. Hist.
IV. p. 252. — Ed.

THE CEPHALOPODA.

273

§ 235.

covered by its anterior border.® The sea- water, which enters into the inte-
rior of the mantle, passes, with its various contents, into this funnel, and is
thence expelled through its anterior orifice.

Many Cephalopoda have, on the dorsal wall of this organ directly behind
the anterior orifice, a tongue-shaped valve, which prevents the reflux of the
water.®

With the Loligina, the sides of the trunk have variously-shaped cutaneous
lobes, which these animals use as fins.® The Octopoda, on the other hand,
swim by rowing with their arms, which are bound together at their base by
a kind of natatory membrane, whose extremities have, each, a broader or
narrower cutaneous dilatation.®

§ 235.

The mantle of many of the Cephalopoda secretes a shell, which may
be either external or internal.

1. An external shell is found with Ar gonauta and the Nautilina. That
of the Paper-Nautilus is very thin and flexible, — and, in its composition,
the organic base predominates above the calcareous matter, which consists
of thickly-set, small, round masses. The substance of the shell, which, with
Ar gonauta,, is nowhere attached to the animal it encloses, is secreted prin-
cipally by the two large cutaneous lobes of the two median dorsal arms,
which lie upon the external surface of the shell. On this account, the
structure of the two surfaces of these lobes is different ; — the external sur-
face is quite smooth and has many chromatic cells; while the internal has
scarce any of these last, but is covered with numerous reticulated, project-
ing lines, which become the more prominent when the lobes are contracted,
and between which, cell-like depressions are formed.®

With the Nautilina, the shell has a very complicated structure ; its walls
ai’e composed of two distinct layers, clearly separate, the internal of which
has a beautiful mother-of-pearl aspect. The cavity of the shell is divided,
even to the last spiral turns, by numerous transverse septa, which are all
perforated. With Nautilus, ® a tube traverses the septa, while with

1 With Nautilus , the funnel is composed of two
pretty large, cutaneous lobes, placed upon both sides
of the throat, and reciprocally covering each other
on the ventral surface in a cornet-like manner j
see Owen, On the Nautilus, p. 10, PI. I. or Isis. p.
10, or Ann. d. Sc. Nat. loc. cit. p. 93, PI. I. III.
and Valenciennes loc. cit. p. 269, PI. X. fig. 1.

2 This is so with Sepia , Sepiola , Loligo , Se-
pioteuthis , Onychoteuthis , and Nautilus. For
this last, see Owen, loc. cit. PI. II. fig. 2, e., and
Valenciennes , loc. cit. PI. XI. fig. 4, I have
sought for it in vain with Ar gonauta , Eledone ,
and Tremoctopus. It is also wanting with Loli-
gopsis and Cranchia ; with Octopus , there exists
in its place, that is, on the ventral surface of the
funnel, a transverse ridge.

o With Sepia , and Sepioteuthis , both sides of
the body are bordered their entire length with a
cutaneous lobe. With Loligo , and Onychoteuthis ,
the two fins are triangular and inserted on the
posterior extremity of the body ; they are round
and short with Sepiola , Loligopsis , and Cranch-
ia ; in the first of these genera, they are situated
on the middle of the sides of the body, and in the
last two, upon its extremity.

4 These interbranchial natatory membranes ex-
ist with Octopus , Eledone , and Tremoctopus ;
they are particularly developed in this last genus,
between the two pairs of dorsal arms.

In this same genus, as also with Ar gonauta, the
two dorsal arms are terminated by a very large
cutaneous lobe, and are used not only as locomo-
tive organs, but also for keeping the shell in place
by being applied on its external surface ; see F e-
russac , loc. cit. Ar gonauta , PI. I. fig. 5, 6, PI. VI.
fig. 2, and in the M4m. de la Soc. d’Hist. Nat. de
Paris, II. 1825, p. 160, PI. VI. fig. 2, or Isis, 1832,
p. 460, Taf. V. fig. 2 •, Rang , Docurn. pour servir
d l’llist. nat. des Cephalopodes, in the Magaz.
de Zool. 1837, Livr. IV. p. 19, PI. LXXXVL-
LXXXVIII., or Ann. d. Sc. Nat. VII. 1837, p.
176 ; and Delle Chiaje , Descriz. loc. cit. Tav. VII;
fig. 1, 2.

1 It has been attested by several observers, that
these two cutaneous lobes furnish the substance of
the shell, and that, also, with which the animal re-
pairs accidental lesions *, see Rang , Magaz. de
Zool. loc. cit.j Jeanette Power , in the Atti dell’
Acad, di Scienz. Nat. di Catania, XII. 1839.
or Isis. 1845. p. 606, or in Wiegmann's Arch.
1845, 1. p. 369 ; and, Further experiments and ob-
serv. on the Argonauta Argo, in the lleports of
the Brit. Assoc. 1844, Notices and Communic. p.
74. For the non-parasitism of the animal, see,
moreover, Van Beneden , loc. cit. p. 4, and Ferus-
sac , loc. cit. p. 114.

2 De Blainville , in the Nouv. Ann. du Museum
d’Hist. Nat. III. 1834, p. 3, PI. I. II.

2T4

THE CEPHALOPODA.

$ 285.

\

Spirula,® an analogous calcareous tube extends close upon the inner sur-
face of the shell from one septum to another. The animal, whose trunk
occupies only the first chamber, is loosely attached to it by the cartilaginous
border of its mantle.

With Nautilus, this border has a lobe which extends along the back of
the animal, surrounding the spiral portion of the shell. <4) With all the
Nautilina, there is another prolongation in the form of a membranous
tube, or Sipho, which arises from the posterior part of the body, — trav-
erses the orifices or calcareous tubes of the septa, and penetrates even into
the last chambers of the shell. These chambers are lined with a thin mem-
brane, and have no external communication except through the Siphon.

2. With the Loligina, an internal shell lies free in the dorsal portion of
the mantle. In most genera, it is composed of a homogeneous, horny
substance, of a yellowish-brown color, and has a form like a feather
(Calamus), or the head of a lance. At one of its extremities is an attenu-
ated stem, and two delicate lateral winglets of variable length.® With
Sepia, this shell differs very much from that of the other Loligina. Its
two surfaces are covered by very distinct calcareous layers, which have
erroneously given it the name of Os sepiae .3 4 5 (6) As a whole, it is tongue-
shaped ; its two surfaces are convex and its borders are sharp. Behind,
the lateral borders become thinner and are slightly bent toward the ventral
surface; and a short conical point projects from the middle of the pos-:
terior border. The horny substance is reduced to a thin sheet, situated
between the calcareous layers, but its borders usually extend out beyond
those of these last. The calcareous layer of the dorsal surface is very
thin, but quite solid, and its surface in front, is granulated and striated ;
that of the ventral surface, on the other hand, is very thick, especially
in the middle, and its very loose tissue contains numerous quite thin,
porous lamellae, which, superposed almost horizontally, alternate regularly
with layers of small, transversely-striated, dichotomous, vertical prisms.®
This ventral layer is truncated obliquely from its middle backwards, and
the horizontal layers may easily be counted upon its truncated surface.®

3 De Blainville , Ibid. p. 18, PI. I. fig. 6, A-F.

4 Owen, and Valenciennes , loc. cit.

5 See Wagner, Icon. zoot. Tab. XXIX. fig. 32
(Loligo), and Fdrussac, loc. cit. ( Loligo , Loli-
gopsis, Onyclioteuthis , Sepiola, and Sepioteu-
this).

I cannot here omit speaking of the remains of an
antediluvian animal, which, under the name of
Aptychus, has much engaged the attention of pa-
laeontologists, and, up to the present time, been the
object of discussion.

Some have regarded it as the operculum of an
Ammonite or of another Mollusk ( Rilppe/l , Abbild.
und Beschreib. einig. Versteiner. von Solenhofen,
1829, and Foltz, in the Neuen Jahrbuch fiir Min-
eralogie, &c., 1837, p. 304, 432) ; other? as a shell
of a bivalve (77. von Meyer , in the Nov. Act.
Acad. Nat. Cur. XV. pt. II. p. 125 and in the
Jahrbuch f. Mineral. &c. 1831, p. 391) •, and oth-
ers, finally, as an internal shell of one of the Ceph-
alopoda ( Coquand. , in the Bull, de laSoc. Geol. de
France, XII. 1840-41, p. 376).

This last opinion is undoubtedly the correct one.
As for myself, I am able to perceive in the different
species of Aptychus only shells whose shaft is abor-
tive, and the wings excessively developed. I was
therefore quite Surprised to hear my colleague, Al-
exander Braun, express himself in a conversation,
that, “after all, the animal called Aptychus

might well have been the male of certain Ammo-
nites.” If the relations of the Ilectocotyli to cer-
tain Octopoda are borne in mind, the idea of
Braun, that there have existed Ammonites, the
males of which are quite different in form from the
females, certainly merits much consideration. For
the males of these animals were, perhaps, abortive
like those of Argonauta and Tremoctopus, and
obliged, therefore, to shelter themselves in the man-
tle of their females, and this would explain why it is
that the specimens of Aptychus are so often found
at the base of the first chamber of Ammonites.

Judging from the form of the shell, the bodies of
these animals must have been very large. There
will be an additional analogy in favor of this view,
if it is proved that the large and flattened animal
found by Quoy and Guimard is really the male of
a Nautilus (§ 233, note 3).

6 The error of Spix (Cephalogenesis, loc. cit. p.
33) in comparing it to a rudimentary vertebral
column, is still wider.

7 According to Kolliker (Entwickel. loc. cit. p.
72, Taf. V. fig. 45, 46) these calcareous prisms be-
gin to be formed in the embryo.

8 A very detailed description of this Os sepiae
has been given by Cuvier (Mem. loc. cit. p. 46),
Brandt (Mediz. Zool. II. p. 301, Taf. XXXI. fig. 3,
6), Wagner (Icon. zoot. Tab. XXIX. fig. 34), and
Ferussac (loc. cit.).

THE CEPHALOPODA.

275

§§ 236, 237, 238.

Although it must be supposed that the calcareous matter of this shell is
secreted by the internal surface of the dorsal cavity, yet the thin fibrous
membrane which lines this last, is without a glandular structure.

CHAPTER III.

MUSCULAR SYSTEM AND ORGANS OP LOCOMOTION.

§ 236.

The muscular system of the Cephalopoda is highly developed. Its prim-
itive fibres are smooth, but are not so diversely interlaced as with the other
Mollusca. These fibres are usually parallel, and the fasciculi which they
form, are of equal thickness. When isolated, they often show a zigzag ten-
dency, which, probably, belongs also to their state of contraction. The
fasciculi are very compactly bound together in one direction by a cellular
tissue, and, in this manner, form clearly-defined, long, flat muscles.

§ 237.

The mantle of the Cephalopoda has a very distinct layer of circular
fibres. (1) 2 From the internal surface of the sac which it forms, arise, in the
dorsal region, two pairs of large cylindrical muscles. One pair of these
passes in front and is extended into the walls of the base of the funnel ;
the other pair extends to the posterior part of the neck, and is inserted
partly into the cephalic cartilage, and partly at the base of the arms. The
other muscles, which are thinner, arise from the sides of the cervical carti-
lage, and are inserted upon the funnel.® By means of a part of this mus-
cular apparatus, these animals can vigorously contract the cavity of the
mantle and the funnel, and, by tightly embracing the neck and base of the
funnel with th^border of the mantle, can eject, through the orifice of this
last, the liquids contained in the cavity of the body. With many species,
these muscular contractions serve, also, as a means of a backward locomo-
tion in the water.

§ 238.

The principal locomotive organs of the Cephalopoda are the arms fixed
upon the cephalic cartilage ; they serve also as prehensile organs. Each
of these consists of a tubular axis composed of a dense cellular tissue, of
muscular fibres radiating towards the surface, between which are inter-

1 This muscular layer is incomplete with Sepia trunk and the head of Cephalopoda may be found

— being wanting in the dorsal portion of the in Cuvier , loc. cit. p. 9 ; Brandt, loc. cit, p. 303*

mantle. and especially in Delle Chiaje, Memor. IV. p. 72,

2 A very full description of the muscles of the ajid Descriz. &c., I. p. 21.

THE CEPHALOPODA.

276

$ 288.

posed others which are longitudinal, and, lastly, of a layer of circular fibres
directly beneath the skin.(l) 2 3 4

Over the entire length of the internal surface of these arms, are suckers,
arranged in a single, double, or multiple row.® But with the Loligina,
these suckers occur in groups of variable extent only at the extrem-
ity of the ninth and tenth arms ( tentacular arms). These suckers are
moved by muscular fasciculi which pass from the arms and are spread upon
the former in a ray-like manner, and which form, moreover, with the Loli-
gina, a peduncle.

With Tremoctopus, the suckers are cylindrical and very simple, while with
the other Octopoda, their opening is closed by a membrane perforated cen-
trally by an orifice which can be closed by a papilla that projects from the
base of the sucker.® These organs are applied to objects at the moment
when the papilla is withdrawn and removed to the base of the sucker.
With the Loligina, the lateral walls of the suckers are very thin, extens-
ible, and have upon their borders a horny and denticulated ring ; in this
ring the fleshy base of the sucker adjusts itself in an urceolate form, and
upon withdrawal, produces a vacuum. With Loligopsis, and Onychoteuthis ,
many of the suckers on the two tentacular arms are imperfect, but, on the
other hand, some of the teeth of their horny border are disproportionably
developed, or the whole is changed into a Strong claw.®

The arm-like processes about the mouth of Nautilus differ very much
from the preceding.® They have no trace of suctorial organs, and are
composed of thirty-eight prismatic filaments, which are a little flattened and
transversely curled.

Each of these filaments is surrounded, at its base, by a contractile sheath
into which it can be wholly withdrawn.® The whole fasciculus is, moreover,
enveloped in a common sheath, which, upon the back, is flattened so as to
resemble the foot of the Gasteropoda, and like it, probably, may serve for
creeping.®

The portion of the skin, which extends as a kind of Natatory membrane
between the arms of many Cephalopoda, contains a very loose net-work of
longitudinal and transverse muscular fibres.®

The fins of the Loligina, have, on the contrary, large muscles composed
of parallel, contiguous fasciculi which arise from the cartilages of these
organs.

1 This axis is usually of a i>rismatic form ; con-
sequently if an arm is cut transversely the section
presents a quadrilateral or rhomboidal spot in its
centre •, see Sauigny, in the Descript, de 1’lCgypte,
Ilist. Nat. PI. I. fig. I. w.-, Owen , in the Cyclop.
1. p. 52S, fig. 214, c, and Fdrussac, loc. cit. Octo-
pus, PI. 11. fig. 3, and PI. XV. fig. 11, b. A sim-
ilar section of the body of an Hectocotylus pre
sents a like aspect.

2 The suckers form a single row with Eledo~ie •,
a double one with the other Octopoda, and with
most of the Loligina ; but the rows are multiple
with Sepia.

3 Although the double row of suckers on the
body of Hectocotylus does not diminish towards
the anterior extremity, yet, in other respects, it so
closely resembles the suckers of Argonaut a and
Tremoctopus , that it may well be asked why this
single fact was not sufficient to discover to the old-
er observers the real nature of this pretended par-
asite.

4 Firussac , loc. cit. Loligopsis , PI. IV. and
Onychoteuthis , PI. VI. VIII. &c.

o Owen, and Valenciennes , loc. cit.

6 The internal structure of these filaments agrees
pretty closely with that of the arms of other Ce-
phalopoda. Owen , On Cephalopods with chamber-
ed shells, loc. cit. p. 8, fig. 131, Cyclop, loc. cit. p.
526, fig. 213, and Annals of Nat. Hist. XII. p.
305.

7 Owen , and Valenciennes , loc. cit.

8 The large cutaneous lobes of the median dorsal
arms of Tremoctopus and Argonauta , have a
similar structure. In this last genus, they are not
used as oars, nor as sails, but are thrown back
upon the shell to keep it in place (§ 235, note 4) •,
they move in the water, moreover, like the other
Cephalopoda, by the contractions of the mantle and
the funnel (Rang, Magaz. d. Zool. 1837, p. 22. PI.
LXXXVII.). It is therefore astonishing that Jea-
nette Power (Wiegmann's Arch. 1845, I. p. 373)
should have revived the old fable that these ani-
mals raise these two large arms above the surface
of the sea to be used as sails.

§§ 239, 240.

THE CEPHALOPODA.

277

With Nautilus, there arc two large, particular muscles, which arise from
the under surface of the cephalic cartilage, and extend, divergingly, back-
wards ; they serve, by means of a horny plate, to fix the animal to the
internal border of the shell.®

CHAPTER IV.

NERVOUS SYSTEM.

§ 289.

The nervous system of the Cephalopoda attains a very high degree of
development. Its central portion, especially, quite resembles the brain of the
Vertebrata, in the extraordinary increase of its ganglionic substance, and
by the presence of a cartilaginous cavity containing it, comparable to a
cranium. This cavity is incomplete, it is true, but at its anterior part
where the cartilaginous substance is wanting, it is closed by a tendinous cel-
lular tissue which takes the place of a Dura mater.

The brain itself, which is far from filling the cavity of the cephalic carti-
lage, is enveloped by a fibrous membrane, which sends off sheaths to the
nerves which leave the brain and traverse, in different places, the cephalic
cartilage. The cavities remaining between the brain and this cartilage are
filled with a fat-like liquid.

The primitive nerve-fibres are straight, finely granulated, and bound to-
gether into fasciculi of variable size by a very distinct neurolemma.® The
long and oval corpuscles which are often found in abundance between them,
belong probably to the neurolemma.

§ 240.

The central mass of the nervous system, with the Cephalopoda, forms also
an cesophageal ring, which consists of a superior and an inferior ganglionic
mass connected by lateral commissures. The superior portion is small and
sends some delicate nerves to the parts of the mouth. The inferior portion
on the contrary, is very large, and extends along the sides of the oesopha-
gus in order to be directly continuous with the broad commissures. The
olfactory, and the two ojatic nerves arise from the lateral portions of this
ganglion, while the auditory nerves have their origin from its inferior
surface.

From its anterior border pass off four or five pairs of large nerves to
the arms, and, also, others to the muscles of the head. From its posterior
border arise small nerves for the funnel, and also two large trunks for the

9 Owen, On the Nautilus, p. 17, PI. IV. fig. 2,
k., or Isis, p. 15, or Ann. d. Sc. Nat. p. 103, PI. II.
fig. 3, k., and Valenciennes , loc. cit. p. 268, PI.
XI. fig. 4, P.

1 Kolliker , Entwickelung. d. Cephalop. p. 79.
According to the researches of Lebert and Robin

24

( Muller's Arch. 1846, p. 128), the histological coi; •-
position of the ganglia with the Cephalopoda is very-
remarkable. They have here found very laiye
ganglionic globules, of even one-twenty-fifth o , i
inch in diameter, and containing, each, sevci 1
nuclei.

278

THE CEPHALOPODA.

§ 241.

back of the mantle.® With Sepia, this inferior portion has several swell-
ings ; from the two anterior of these, which are the largest, arise the nerves
of the arms; while the two lateral posterior send off the two optic nerves.®
With Nautilus , this same portion is divided into an anterior and a pos-
terior transverse band,® which may be compared, to a certain extent, to
the semi-circle of ganglia upon the inferior surface of the oesophagus with
certain Gasteropoda.

§ 241.

Among the Peripheric nerves, those of the arms and mantle should be
specially mentioned.

The Brachial nerves enter into the axial canals of the arms at the base of
these last, and extend even to their extremity after intercommunicating, each,
by a transverse anastomosis with the two neighboring nerves.® In their
course through this canal, they give off numerous filaments to the muscular
substance of the arms and to the suckers. With the Octopoda, these nerves
are composed of two parallel cords, each one of which has, alternately right
and left, ganglionic enlargements.®

The two Pallial nerves, which are easily seen from their size, pass, at
first, between the cervical muscles, and, having reached the internal sur-
face of the back of the mantle, terminate in two vex-y large ganglia ( Gan-
glion stellatum ) from the external border of which pass off numerous nerv-
ous filaments, which enter, ray-like, the fleshy portion of the mantle.® With
those Loligina, which have fins, the pallial nerves, before terminating in
the star-like ganglia, send off a large branch, which, at a short distance from
its origin, is joined by another large branch from the pallial ganglion, and
is then distributed to the muscles of the fin.® With the long-bodied spe-
cies of this family, this nerve pursues a long course by the side of the me-

1 The nervous system of the Cephalopoda has
been carefully described by Cuvier , M6m. p. 34,
PI. I. fig. 4 (Octopus); Brandt , Mediz. Zool. p.
308, Taf. XXXII. fig. ‘23 (Sepia); Owen , and Va-
lenciennes y loc. cit. ( Nautilus ) ; and by Van Be-
neden , loc. cit. (Argonauta) ; see, moreover, the
figures given by Owen, of that of Sepia (On the
Nautilus, PI. VII. fig. 3, or Isis, 1835, Taf. IV. 7,
fig. 3, or in the Ann. d. Sc. Nat. XXVIII. PI. III.
fig. 5, and Cyclop. I. p. 549, fig. 232), and those of
Loligo , Sepia , and Octopus , in Delle Chiaje ,
Memor. &c. Tav. XCV. C.-CIL, and Descriz. Tav.
XXV. XX IX. -XXXI*

2 Brandt , loc. cit.

•3 Owen , On the Nautilus, p. 36, PI. VII. fig. 1,
or, Isis, 1835, p. 30, Taf. IV. 7, fig. 1, or, Ann. d.
Sc. Nat. XXVIII. p. 134, PI. III. fig. 4, and Va-
lenciennes, loc. cit. p. 287, PI. VIII. fig. 2—4.

1 Cuvier , Mem. p. 36, PI. I. fig. 4, (Octopus);
I)elle Chiaje , loc. cit. Tav. CII. (29), C. (31), (Oc-
topus and Sepia); Ferussac , loc. cit. PI. I», fig.
1, and Van Beneden , loc. cit. p. 15, PI. II. fig. 2,
and PI. IV. (Argonauta).]

* [§ 240, note 1.] See especially the excellent
illustrations of Milne Edwards , R£gne anirn, loc.
cit. PI. Ib. See, for a very detailed description
of this system with Ommastrephes , Hancock
(Ann. Nat. Hist. X. 1852, p. 1), who has sought to

2 Van Beneden , loc. cit. p. 14, PI. II. fig. 3-5,
PI. III. fig. 4, and PI. IV. (Argonauta). I have
found the same organization with Octopus , and
Trem octopus. In this last genus, the ganglia
may, from their reddish color, be very clearly sepa-
rated from the white nervous substance. Both the
smooth and the nodulated cords send off nerve-fila-
ments, but with the last, they arise exclusively from
the ganglionic swellings.

I have been unable to decide if the smooth cords
send off filaments only to the muscles, and the nod-
ulated ones to the suckers ; or if the first contain
only motory fibres, and the second sensitive fibres.
I should add that in the axis of Hectocotylus
tremoctopodis I have also found a highly-devel-
oped, nodulated trunk, the number of swellings of
which corresponded with that of the suckers.

3 See the figures of Van Beneden , Delle Chi-
aje , Brandt, loc. cit., and of Owen , in the Cyclop.
I. fig. 232 (Argonauta, Octopus , Loligo , and
Sepia).

4 See the figures of Delle Chiaje , and Owen ,
loc. cit. (Loligo and Sepia).

point out the homologies of the Cephalopoda with
the Mollusca. — Ed.

f [ § 241, note 1.] See also the illustrations of
Milne Edwards , R£gne animal, loc. cit. PL I. fig.
3, f. f. (Argonauta). — Ed.

§ 242.

TjlE CEPHALOPODA.

279

dian line of the body until it reaches the base of the large fin-muscles, situ-
ated at the extremity of the body.®

With Nautilus, numerous filaments arise from the posterior ganglionic
band, and, without forming a ganglion, are distributed to the two muscles
of the shell. From their origin, they may be regarded as the representatives
of the pallial nerves of the other Cephalopoda.®

Another pair of nerves corresponding to the Pneumogastric nerves of the
Vertebrata, arises from the middle of the inferior cerebral mass, between
the two pallial nerves, descends along the neck behind the funnel, the pos-
terior wall of which it pierces, and thence passes under the peritoneum ;
here it sends several nerves to the ink-sac, and then ramifies upon the heart,
the large vascular trunks, the branchial hearts, and the branchiae. Both
of these nerves have ganglia, here and there, in their net-works, (l) and these
net-works communicate probably with the Plexus splanchnicus posterior.

§ 242.

The Splanchnic nervous system is particularly developed with the Ce-
phalopoda. It may be divided into an anterior and a posterior plexus.®
The Plexus splanchnicus anterior consists of a Ganglion pharyngeum
inferius, situated under the oesophagus sending filaments forwards to the
parts of the mouth, and backwards' to the oesophagus, and connecting
at the same time with the inferior cerebral mass by two commissures.®
With the Loligina, there is, beside, opposite this ganglion, a Ganglion
pharyngeum superius, which, also, sends several filaments to the parts of the
mouth, gives off two filaments to the inferior oesophageal ganglion, and
appears to connect, likewise, with the superior cerebral mass.®

The Plexus splanchnicus posterior is characterized by a large Ganglion
gastricum lying upon thiFstoinach. From thig, filaments pass off in differ-
ent directions to the other viscera, and it receives two filaments of commu-
nication, which, after having arisen from the inferior pharyngeal ganglion,
accompany the oesophagus throu'gh the oesophageal ring.®

•r> Delle Chiaje , loc. cit. Tav. XCV. (25) and Cl.
(30), ( Loligo ). The two parallel nerves which, with
Loligopsis , extend backwards along the inferior
dorsal surface of the mantle belong also to this class
of nerves. Grant (loc. cit. p. 21, PI. II. fig. 5, 6),
has compared them to the spinal marrow of Verte-
brata. With Onychoteut/iis , I have also seen the
two nerves of the lins running along the internal
surface of the mantle, while with Loligo , as Delle
Chiaje has indicated in his Tav. Cl. (30), they af-
terwards pass into the muscular layer of the man-
tle and continue their course between it and the
Skin, sending off filaments to the two muscles of the
fins.

Owen , On the Nautilus, p. 38, PI. VII. fig. 1,
No. 13, or, Isis, p. 32, Taf. IV. 7, fig. 1, or, Ann. d.
Sc. Nat. p. 137, PI. III. fig. 4, No. 13.

7 These two nerves, analogous to the Par vagum ,
have been observed by all the Anatomists of these
animals 5 see Cuvier Mem. p. 36, PI. I. fig. 4, ,u.
(Octopus) ; Brandt , loc. cit. Tab. XXXII. fig. 3,
g. and fig. 23, k. j Owen , Cyclop, loc. cit. I. fig.

232, c. (Sepia); Van Beneden, loc. cit. p. IS, PI.
I. fig. 7, h. PI. II E. fig. 5, k. and PI. IV. r. (Argo-
nauta) ; Owen, On the Nautilus, PI. VII. fig. 1,
No. 15, or, Isis, Taf. IV. 7, fig. 1, or Ann. d. Sc.
Nat. PI. III. fig. 4, No. 16 (Nautilus) ; and Delle
Chiaje , loc. cit. Tav. XCV. (25), C. (31), and CII.
(29), (Loligo, Sepia, and Octopus).

1 For the sympathetic nervous system see Brandt ,
Ueber die Mundmagennerven der Evertebraten,
loc. cit. p. 40.

2 Brandt , Mediz. Zool. II. p. 309, Taf. XXXII.
fig. 23, 3 ; Owen, Cyclop, loc. cit. fig. 232 (Sepia);
Van Beneden, loc. cit. p. 16, PI. II. fig. 6 (Argo-
nauta); Delle Chiaje, loc. cit. Tav. XCV. C.-CII.
(25, 29-31), ( Loligo , Sepia, and Octopus).

3 Brandt, Owen, and Delle Chiaje, loc. cit.
(Sepia and Loligo).

4 Van Beneden, loc. cit. PI. III. fig. 1-3, and
PI. IV. (Argonauta) ; Brandt , loc. cit. Taf.
XXXII. fig. 3, 20 ; and Delle Chiaje, loc. cit.
Tav. C. (31), and CII. (29), (Sepia and Loligo).

280

THE CEPHALOPODA.

§ 243, 244, 245.

CHAPTER Y.

ORGANS OF SENSE.

§ 243.

The sense of Touch is well developed with the Cephalopoda, and is situ-
ated in the whole cutaneous envelope, in the fringed labial membranes, and,
especially, in the arms.® Nautilus is particularly rich in tactile organs,
which are situated on the head ; and this animal has, beside the thirty-eight
tentacular arms, two external, and two median, large, labial prolongations,
placed about the mouth, the border of which has twelve small,” curled
filaments, whose internal structure cpiite resembles that of the arms.

The nerves of the filaments of the two external of these prolongations
have an origin common with those of the arms, arising, consequently, from
the front border of the anterior cerebral band. Those of the filaments of
the median prolongations arise from the same band (but nearer the median
line), by two common roots which, before dividing, have a flat ganglion.®
This animal has, also, four other curled tentacles, which can be retracted in
a sheath, two in front of, and two behind, the eyes. These tentacles receive
a special tactile nerve, which has its origin by the side of the optic nerve.®

§ 244.

With the Cephalopoda, the fleshy point of the tongue is undoubtedly a
Gustatory organ. It is concealed in the anterior angle of the lower jaw,
and its rounding surface is covered with numerous soft villosities, which very
probably serve as gustatory papillae.®

§ 245.

The Olfactory organs of the Cephalopoda are situated in the neighbor-
hood of the eyes, and consist, each, of a cavity with tumid borders, or of
a cutaneous fossa which has an opening, and, sometimes, at the bottom, a
whitish papilla. The nerves of these organs arise from the optic ganglion
of the oesophageal ring, near the optic nerves. At first, they are closely
united with these last, enter the orbit with them, and extend along its poste-
rior wall, thence to the olfactory papillae, to which they are distributed in a
ray-like manner.®

1 Touch appears the only sense developed with
Hectocotylus. If Costa's figure (Ann. d. Sc. Nat.
XVI. PI. XIII. fig. 21 * 3, e. f.) is exact, Hectocoty-
lus argonautae has a special tentacle-like tactile
organ on the anterior extremity of the body.

- Owen , On the Nautilus, PI. IY. PI. VII. fig. 1,
or Isis, 1835, Taf. III. IV., or Ann. d. Sc. Nat.
XXVIII. PI. II. fig. 1, PI. HI. fig. 4.

3 Owen and Valenciennes , loc. cit. PI. VUI.
fig. 2, i. and PI. IX. fig. 1, i.

1 This organization appears to have eluded the
observation of most naturalists. I have seen it
very distinctly, not only with the Loligina, but also
with the Octopoda. Owen (On the Nautilus, p. 23,
PI. \TII. fig. 7, or, Isis, p. 20, Taf. II. or, Ann. d.
Sc. Nat. p. 113, PI. IV. fig. 7, and Cyclop. I. p.
554, fig. 236,) and Valenciennes (loc. cit. p. 280,
Pi. X. fig. 3, 4,), only, have represented with Nau-

tilus this part of the tongue as having all the char-
acteristics of a gustatory organ. With Sepia, the
soft papillae have already been figured by Sa vigny
(Descript, de l’lSgypte, loc. cit. PI. I. fig. 4, 5, and
in Ftrussac, loc. cit. Sepia , PI. IV. fig. 2-, 3:1).

1 The cavities here mentioned were for a long
time regarded as the external auditory passages,
and the cutaneous folds surrounding them as a Pa-
vilion ( F&russac , loc. cit.), until Kulliker ( Fro -
riep's neue Notiz. XXVI. 1843, p. 166, and, Ent-
wickel. d. Cephalopoden, p. 107) discovered a
special nerve, and declared, with reason, that the
whole was an olfactory organ. The Cephalopoda
being poor in vibratile organs, it is quite desirable
to ascertain if these olfactory organs are ciliated,
for they are so in fishes with which ciliated epithe-
lium is likewise feebly developed.

§246.

THE CEPHALOPODA.

281

With Nautilus, the two olfactory papillae are situated, directly beneath
the eyes, in a cavity which is surmounted by a wart-like swelling.® With
the Octopoda, the olfactory organs are concealed, behind the eyes, in the an-
gle of insertion of the mouth upon the occiput. With Argonauta, and
Tremoctopus, they consist of two naked papillae ; and with Octopus, and
Eledone , of two membranous cavities. <3)

With the Loligina, these organs are situated behind and a little below
the eyes, and consist of fossae having narrow apertures ; but they are easily
seen from the elongated or round cutaneous swelling with which they are
surrounded.®

§ 246.

The Auditory organs of the Cephalopoda are situated in the lower mid-
dle portion of the cephalic cartilage, where they form two more or less
large, round cavities, separated by a cartilaginous septum, and without
any external communication.™ With the Octopoda, the internal walls of
these cavities are smooth ;® but with the Loligina they have many tuber-
cles or papillae, which are sometimes quite prominent.® This portion of
these organs may best be compared to the osseous Labyrinthus of the Verte-
brata. These cavities are filled with a liquid substance, and contain, also,
each, a small pyriform sac — membranous labyrinth — adhering to the car-
tilaginous labyrinth at the point where the . auditory nerve enters it, and
upon which this nerve is spread out. This sac contains a single, white,
irregular otolite of a crystalline texture.®

2 Valenciennes (loc. cit. p. 290, PI. VIII. fig.
2, h. PI. IX. fig. 1, h. x., anti fig. 3) in 1841,
and consequently before Kolliker , described these
organs as olfactory with Nautilus'. He found not
only the nerve which goes to the olfactory papilla,
but also an orifice at the base of this last, leading
into a cavity lined with a mucous membrane which
had two regular rows of folds. Owen (On the Ceph-
alopods with chambered shells, p. 11) has regarded
these papillae, which he appears to have complete-
ly overlooked in his earlier memoir, as short hol-
low tentacles. On the other hand, he regards as
the olfactory organs a row of twenty membranous
lamellae arranged longitudinally at the entrance of
the mouth between the two internal labial prolon-
gations (On the Nautilus, p. 41, PI. IV. 1., PI.
VII. fig. 1, g. fig. 2, or Isis, p. 34, Taf. III. IV.,
or Ann. d. Sc. Nat. p. 141, PI. II. fig. 1, 1., PI. III.
fig. 4, g. fig. 6); but it would appear to me that
these lamellae are tactile lobules, for they receive
numerous nerve-filaments from the ganglia of the
nerves of the internal labial prolongations (Owen,
loc. cit.).

3 With Argonauta , and Tremoctopus , these ol-
factory nerves have a ganglion lying on the optic
nerve ( Kolliker , Entwickel. d. Ceph. p. 168)-, this
was seen by Van Beneden (loc. cit. p. 13, PI. I.
fig. 5, 6, k.), but not explained. The olfactory
cavities of Octopus did not, indeed, escape the no-
tice of Rapp (Naturwiss. Abhandl., von einer Ge-
sellsch. in Wtirtemberg, 1826, p. 69), and of Delle
Chiaje (Descrij. &c. Tav. VI. fig. 1. k. and Tav.
XVIII. fig. 1, y), but they did not in the least sus-
pect their nature.

4 According to Owen's account accompanied
with a figure (On the Nautilus, pi. VII. fig. 3, No. 9,
or Isis, 1835, Taf. IV., or Ann. d. Sc. Nat. XXVIII.
PI. III. fig. 5, No. 9, and Cyclop. I. p. 549, fig.
232, k), the olfactory nerves of Sepia and Loligo
appear to arise from a special ganglion situated

24#

near the Ganglion opticum. The entrance, with
its tumid borders, of the olfactory caviiies, has
often been figured with the Loligina, by Ftrussac
(loc. cit. Sepia , PI. XVII. fig. 2. c. PI. XVIII. fig.
3, b. PI. XXVII. fig. 1, 6 ; Loligo , PI. XX. fig.
7, PI. XXIII. fig. 5, 17, PI. XXIV. fig. 2, 14 ;
Sepioteuthis , PI. VI. fig. 2, b.; Sepiola , PI. III.
fig. 5, 15 b.).

1 It has already been seen (§ 245) that the olfac-
tory organs of the Loligina have been taken by
some naturalists for an external ear.

A very remarkable organ — a tiexuous canal
lined with ciliated epithelium, has been seen by
Kolliker (Entwick. d. Ceph. p. 105, fig. 60-63),
but, only with the embryos of Sepia and Loligo j
departing from the auditive vesicles, it ran in
front without opening either upon the surface of
the body, or into the oesophagus, so that it could
have been neither an external auditory duct, nor a
Tuba Eustachii.

2 See Scarpa , Anat. disquis. de auditu et olfac-
tu, p. 3, Tab. IV. fig. 11 (Octopus); Delle Chiaje ,
Descriz. &c. Tav. XIV. fig. 1, d.; and Van Bene-
den, loc. cit. PI. I. fig. 3 (Argonauta).

3 See Brandt , Mediz.Zool. p. 309, Taf. XXXII.
fig. 14 j Wagner , Icon. zoot. Tab. XXIX. fig. 37-
39 •, Owen , Cyclop. I. p 554, fig. 235, and Trans-
act. of the Zool. Soc. II. PI. XXI. fig. 17 ; and
Delle Chiaje , Descriz. &c. I. p. 68, Tav. XII. tig.
12, 21 (Sepia and Loligo). This last-mentioned
author has compared some of these cartilaginous
prominences to the Ossicula of the ear ; but to me
they appear to represent rather the first traces of
semicircular canals, which, with the embryos of
fishes, appear to consist, likewise, of simple prom-
inences on the internal surface of the auditive vesi-
cle.

4 These otolites are composed mostly of carbon-
ate of lime, and vary considerably in their forms.
With the Octopoda, they resemble, more or less, a

282

THE CEPHALOPODA.

§ 247.

The auditory organs of Nautilus are somewhat different. They are
widely separated from each other, and situated in the prolongations of the
cephalic cartilage which extend in front ; they consist of a very long, nar-
row labyrinthian cavity containing a homogeneous, thick liquid without
otolites.®

§ 247.

The Eyes of the Cephafopoda are very highly developed and dispro-
portionately large. (1) Although resembling very much those of the Yerte-
brata, yet they differ from them in many respects.® With the Octopoda,
and Loligina, each eye has an ocular Bulb and a Capsule.

The capsule is formed by the cartilaginous orbit, and by a fibrous mem-
brane attached to the borders of this last, and is blended externally with
the cutaneous envelope. This envelope, in the form of a circular swelling,
covers the eye, and, being thin and transparent, takes the place of a Cornea,
— a part which, properly, does not exist with the Cephalopoda.®

The circular swelling often has, above and below, a semilunar fold of
skin containing muscular fibres, which, upon contraction, cover the con-
vexity of the eye like an upper and under lid. The ocular bulb, contained
in this capsule, is round and a little flattened in front; and, as it is not ad-
herent to its capsule in front nor upon the sides, there is a free space,
which, from the absence of a cornea, would coincide with the anterior
chamber of the eye.(4) In most cases, this space contains a transparent
liquid, and is lined by a serous membrane covering not only the posterior
surface of the anterior part of the capsule, but also the anterior surface of
the bulb. It is remarkable that this same space, which contains in part
the anterior chamber, communicates, externally, by a circular orifice which,
with the Octopoda, is covered by the upper lid, and with the Loligina, is
situated upon the anterior border of the cutaneous fold which takes the
place of the cornea. Internally, this space can be closed by a kind of fold

disc, concave on one side, and very convex and
sometimes even conical, on the other Scarpa , loc.
cit. Tab. IV. fig. 9, and Weber , De Aure et Audi-
tu, p. 11, Tab. II. fig, 8, (Octopus) ; also Delle
Chiaje , Memor. Tav. LVIII., and Descriz. &c.Tav.
XII. fig. 15, 19, 23, 24, (Octopus and Eledone).
With Octopus , they have a crystalline structure ;
but with Eledone , where they are very flat and
colored brown on one of their surfaces, tftey con-
sist of a soft limeless substance, — often rendering
in vain the search for them in specimens long pre-
served in alcohol.

The irregular otolites of the Loligina, which ap-
pear bristling with points and serratures ( Scarpa ,
loc. cit. Tab. IV. fig. 8, and Delle Chiaje , loc.
cit. Tav. LVIII. (12) fig. 13, 14, 16, 25, 26, (Se-
pia and Loligo ),), have the aspect, under the mi-
croscope, of an aggregation of very fine, acute
prisms, the points of which turn inwards ( Carus ,
Lelirb. d. vergleich Zoot. I. p. 358).

5 See Valenciennes , loc. cit. p. 291, PI. VIII.
fig. 2, No. 3, and PI. IX. fig. 4, 5, a. He has
seen it supplied with nerves coming directly from
the brain. Owen (Qn the Cephalop. with cham-
bered shells, p. 10) took them for venous sinuses,
and could not admit that they were auditive or-
gans, since they contained no otolites. But it
might be argued that these otolites are limc-less like
those of Eledone , and may, therefore, dissolve and
entirely disappear after death.

1 The largest eyes ^re found with the Loligina ;
the smallest with the Octopoda.

2 For the structure of the eyes of Cephalopoda,
see, beside Cuvier , Mem. p. 37, PI. II. fig. 5, and PI.
Ill, fig. 7, and Owen , Cyclop. I. p. 551, fig. 234,
— Mass alien, Descript, oculorum Scombri Thynni
and Sepiae, L>iss. Berol, 1815, p. 10 ; Soemm.er -
ring , De Oculorum hominis animaliumque section©
horizontali, p. 76, Tab. III.-, De Blainville , Princ.
d’Anat. comp. p. 441 ; Mayer , Analekt. f. vergleich.
Anat. lift. I. p. 52 •, Krohn , Nov. Act. Acad. Leop.
Carol. XVII. Pt. I. p. 339, Tab. XXVI., and XIX.
Pt. II. p. 43 5 Wharton Jones , Loud, and Edinb.
Philos. Mag. 1836, Jan’y, or Froriep's Notiz.
X LVIII. p. 2, fig. 1-3 ; Delle Chiaje , Descriz.
&c. I. p. 70, Tav. XIX. arid XXIX. also Osservaz.
Anatom, su l’occhio umano 1838, Tav. IX. fig. 1-
11 ; Valentin's ideal section of an eye of a Cepha-
lopod, in Wagner's Icon. zoot. Tab. XXIX. fig.
42 5 and John Power , Dublin Jour, of Med. Sci-
ence, XXII. 1843, p. 350.

3 Krohn , Valentin , and others, admit the exist-
ence of a particular horny substance situated be-
tween the cutaneous layers of the anterior part of
the ocular capsule.

4 Treviranus (Vermischte Schrift. III. p. 154;
says he has observed a thin, transparent, but solid
membrane, placed directly in front of the lens, and
continuous with the conjunctiva (Argentea), thus
forming a completely-closed anterior chamber ; but
this statement requires confirmation.

THE CEPHALOPODA.

283

§ 247.

or Pupil. The serous membrane just mentioned, which is spread over the
ocular bulb even to the papillary border of the iris, contains a particular
pigment of a silvery lustre, called the Argentea, and comparable to a Con-
junctiva. m

With Onychoteuthis, Loligopsis, and allied genera, the anterior wall of
the ocular capsule is entirely wanting, and as there is also no cornea, the
crystalline lens is in direct contact with the surrounding medium (the water
of the sea). In the first of these genera, the free border of the capsule has,
in front, a deep fissure corresponding, perhaps, to a lachrymal canal.®

The Iris is formed from the argentea, which is covered on ijs posterior
surface by a black Uvea, while its anterior surface often has chromatic cells.

The-pupil is usually of a transverse, or semilunar, rarely of a circular-
form, and is capable of being completely closed.® Under the Argentea
extends a thin cartilaginous tunic — Sclerotica — which, behind, circum-
scribes the ocular bulb, and, in front, penetrates a certain distance into the
iris. It furnishes points of insertion for the muscles of the eye, and is crib-
riform behind for the passage of numerous filaments of the optic nerve.

The cavity of the bulb is filled with a transparent, watery liquid which
takes the place of the vitreous body, and is contained in a very thin Hya-
Icridea.

The Crystalline lens is spherical, and lodged in a deep depression of the
vitreous body. It is of a brownish color, and its anterior surface projects
through the pupil, so that the posterior chamber of the eye is only a small
circular space. As with the Vertebrata, this organ is composed of numer-
ous concentric layers, but has the remarkable peculiarity of being divisible
into halves, the anterior of which is less convex than the posterior, but
both are exactly joined together ; the borders of these halves are quite
bevelled, but are kept in place by the Ciliary body which arises from the
sclerotica and iris. One part of this ciliary body embraces the borders of
the lens, while the other penetrates between its halves as a thin, transparent
septum.®

5 Zootomists are not agreed upon the interpreta-
tion to be put on this membrane. Krohn ,, and

Owen (loc. cit.), who regard the anterior part of
the ocular capsule as a cornea covered by a con-
junctiva, consider the cavity found behind it as a
large anterior chamber, filled with a Humor aque-
us. Cuvier , Wharton Junes (loc. cit.), and J.
Muller (in his Arch. 1836, Jahresb. p. 91), re-
gard the capsular cavity with its serous membrane,
as a closed conjunctival sac *, so that the transpa-
rent convexity of the capsule is not a cornea, but
a continuous closed eyelid. Moreover, as there
are often found two rudimentary eyelids in the
eyes of Cephalopoda (Mayer, Analekt. f. vergleich.
Anat. Hft. I. p. 52, Taf. IV. fig. 6-11), this trans-
parent convexity may be regarded as a third lid
or a nictitating membrane adherent throughout ex-
cept at the point of the opening. Many anatomists,
and especially Cuvier , and Owen , have not no-
ticed this opening of the ocular capsule. But De
lUainville (Princip. d’Anat. comp. I. p. 444, and
Diet. d. Sc. Nat. XLVIII. p. 262) mentions it with
Loli.go , Octopus, and Sepia ; and Wagner (Ana-
lekt. &c. p. 53) has described it carefully.

In the large work of Ferussad, it is often fig-
ured under the name of Orifice lacrymal : see
Loligo , PI. XX. fig. 7, PI. XXIII. fig. 5, a. 17,

* [§ 247, note 8.J The microscopic structure of
this lens corresponds also with that of the Verte-
brata — that is, composed of delicate tubes or fibres.

PI. XXIV. fig. 2, d, 14 ; and Sepiola, PI. III. fig.
5, 15. a, PI. VI. fig. 2. a, PI. IV. fig. 10. a.

0 On account of this singular organization, D’Or-
bigny (in Ferussac, loc. cit. Introduct. p. 15) has
separated, under the name Oigopsidds, the genera
mentioned in the text from the other Loligina which
he calls Myopsides. The segment of the border of
the capsule, and which is wanting with Loligopsis ,
is spoken of as a Sinus lacr ymalis in Ferussac,
loc. cit. Onychoteuthis, PI. III. fig* 1, PI. III. tig.
2, PI. XII. fig. 4, 13, PI. XIV. fig. 1 5 Ommastre-
phes, PI. I. fig. 15, PI. II. fig. 3, 11.

1 The pupil is not circular except with Onycho-
teuthis, Ommastrephes, and Loligopsis.

The upper papillary border, usually convex
with the other Cephalopoda, is often prolonged as
a Velum or Operculum pupillare. With Sepia, it
is often bilobed after death •, see the figures of Fe-
russac,\oc.c\l. and Delle Cliiaje, Osservaz. anat.
loc. cit. Tav. IX. fig. 1, 2, 3.

8 For the lens and the ciliary body, see Huschke,
Comment, de pectine in oculo Avium, 1827, p. 9,
fig. 11, and Delle Chiaje, Descriz. &c. Tav. V.fig.
18, and Tav. XIX. fig. 6-8. Although Mayer
(Analekt. loc. cit. p. 54) declares that this lens has
a capsule, yet I am undecided on this point, for the
other anatomists are silent.*

These fibres however are more than twice as small
as those of any of the Vertebrata I have examined.

— Ed.

284

THE CEPHALOPODA.

§ 247.

The Optic nerves enter the posterior part of the orbit through a kind of
Foramen opt icum, after which they swell into a large kidney-shaped ganglion
in which a portion of the nerve-fibres are completely interlaced with those
from the opposite side.<9> Leaving this Ganglion opticum, the nerve
divides into numerous filaments which traverse the cribriform sclerotica,
and then unite with the other elements of the Retina. The external layer
of the retina is composed of these filaments ; beneath it, is a pigment layer
of a reddish-brown color, and pierced by numerous fibres given off rectan-
gularly from the external layer. The internal layer is composed of gran-
ules, among, which the fibres of the optic nerve probably terminate.™ The
external layer is continuous as a thin membrane upon the ciliary body,
and even upon the septum of lens.(11)

The two optic ganglia are enveloped by a peculiar white substance com-
posed of fat-cells, which, perhaps, serves only as a fat-cushion. (12) The
eye is moved by several straight and oblique muscles, which arise from the
cartilaginous portion of the orbit, and are inserted, usually, upon the mid-
dle of the bulb.

But with Nautilus, the eyes differ in many respects from those of the
other Cephalopoda. They are supported upon a muscular stalk and pro-
ject from the head ; while with the other Cephalopoda, excepting Loligopsis,
they are sunken deeply in the head.™ From the rudimentary lower lid a
narrow furrow passes over the anterior surface of the eye even to the small,
circular pupil. As yet, neither cornea nor lens has here been found.™

9 For the interlacement of the nerve-fibres in the
Ganglion opticum , — see, especially, Wharton
Jones , and John Power, loc. cit.

10 the intimate, very complicated structure of the
retina, has been described principally by Trevi-
ranus (loc. cit. p. 155), Wharton Jones (loc. cit.),
and Paccini (Nuove ricerche microscop, sulla tes-
situra intima della retina nell’ Uomo, nei Vertebrati,
nei Cefalopodi e negli Insetti. Bologna, 1845, p. 55,
fig. 13, 14). The mysterious phenomenon, that,
according to the older anatomists, the surface of
the retina exposed to the light is covered with a
pigment-layer, rests only on an imperfect knowl-
edge of the structure of this organ, as has been
shown by Wharton Jones (loc. cit.), and Valen-
tin (Repert. f. Anat. II. 1837, p. 109).

11 See Krohn , and Wharton Jones , loc. cit.

12 Mayer (Analekt. &c. p. 53) regards this sub-
stance as a semi-adipose gland with several excre-
tory ducts, — a kind of lachrymal gland the product
of which is poured into the conjunctival sac 5 but
Kdlliker (Entwick. d. Ceph. p. 103) could find
nothing glandular in its structure.

13 For the pedunculated eyes of Loligopsis , see
Rathki , in the M£m. d. St. Petersburg, loc. cit.
Pi. I., and V ir us sac, loc. cit.

14 The eyes of Nautilus having been studied for

a long time upon dead specimens, it may be sus-
pected that the exceptionable peculiarities ob-
served by Owen, and Valenciennes, are referable
to the want of fresh specimens. It is, at first,
singular that Owen (On the Nautilus, p. 39, PI. I.
v. w., or Isis, p. 32, Taf. I. 1, fig. 1, v. w., or Ann.
des Sc. Nat. p. 139, PI. I. fig. 1, v. w.) speaks of a
ridge, and Valenciennes (loc. cit. p. 289, PI. IX.
fig. 1, No. 3) of a furrow, running from the border
of the lower lid to the pupil. As the cornea is
wanting, it might almost be supposed, from examin-
ing Valenciennes'1 figure (PI. VIII. fig. 2, P.), that
Nautilus belonged to the OigopsicUs of D'Or-
bigny , except, that with this animal, instead of a
complete absence of the anterior part of the ocular
capsule, there exists only a fissure, regarded by one
of the authors in question as a ridge, and by the
other as a furrow. The lens, not perceived by
either Owen, or Valenciennes, escaped perhaps
through this fissure, after having been detached
by maceration.

As for the pigment layer, spoken of by Owen,
as situated upon the concave surface of the retina
of Nautilus, this problem will be explained, from
researches upon fresh specimens in the same way,
as with the other Cephalopoda.

$$ 248, 249.

THE CEPHALOPODA.

285

CHAPTER VI.

DIGESTIVE APPARATUS.

§ 248.

The mouth of the Cephalopoda (1) * 3 4 is always surrounded by the arms,
(which serve partly as prehensile organs), and by a circular fleshy lip which
is fringed or denticulate on its free border. It is, moreover, covered ex-
ternally by a thin cutaneous fold having a crucial opening. With the
Loligina, there is, beside, a third external lip, arising as a cutaneous fold
from the base of the arms ; it has an heptagonal, rarely an octagonal,
opening, from the angles of which project longer or shorter tentacular
prolongations.® With Nautilus, this lip is extraordinarily developed, —
having four considerable prolongations provided with long tentacles.®
Behind these lips is a round pharynx, very fleshy, and armed with two
blackish-brown, horny jaws, which move against each other vertically.

Upon each of these jaws are two large lateral branches which join at an
acute angle, thus forming a hooked point. The edges of these jaws being
very sharp, the whole has the form of a reversed parrot’s-beak, for, the
edges of the lower jaw project far beyond those of the upper.® The
pharynx is enveloped by a very complicated muscular apparatus, which
arises in part from the cephalic cartilage, and moves the jaws as well as
serves in producing the protraction and retraction of the pharynx.®

Between the two branches of the lower jaw is a Tongue, which is fleshy,
and resembles a long swelling adherent to the floor of the oral cavity.
Upon its anterior extremity are soft gustatory papillae, and over the rest
of its surface there are horny lamellae arranged in regular longitudinal
rows, and golden-yellow spines which point backwards.® Its posterior
extremity is often folded over, thereby forming a kind of cavity, the open-
ing of which is directed backwards, and continuous with a semi-canal lead-
ing into the oesophagus.

§ 249.

The intestinal canal of the Cephalopoda is wholly without ciliated epi-

1 I have been unable to find in Hectocotylus tre-
moctopodis , the orifice which Cuvier (Ann. d. Sc.
Nat. loc. cit. p. 151, fig. 1, 3, 4. f.. or l3is, 1832,
p. 560, Taf. IX., or Froriep's Notiz. loc. cit. p. 8,
fig. 16, 18, 19, f ) has regarded as a mouth with
Hectocotylus octopodis; and as Kolliker (loc. cit.)
says nothing about a digestive apparatus with
these animals, I suspect that it is wanting here,
nutrition taking place by cutaneous absorption
while these bodies are in the mantles of their
females.

9 See Fdrussac , loc. cit. the figures for Sepia ,
Loligo , Sepioteuthis , Onychoteuthis, and Om-
mastrephes.

3 See § 243.

4 Cuvier , M<6m. p. 25, PI. III. fig. 6 ; Savigny ,
Descript, de l’Jfigypte, loc. cit. PI. I.-, Delle Chiaje ,
loc. cit. Tav. LX. (10) fig. 9 j lVagnery Icon. zoot.
Tab. XXIX. fig. 18 ; and the numerous figures

given by FSrussac , loc. cit. According to Owen
(On the Nautilus, p. 20, PI. VIII. or Isis, p. 18, Taf.
I. or Ann. d. Sc. Nat. p. 109, PI. IV.), with Nautilus ,
the extremities of the jaws are covered with a blu-
ish-white calcareous substance, and the border of
the lower jaw is denticulated 5 but Valenciennes
(loc. cit. p. 279, PI. XI. fig. 1, 2) has not con-
firmed these observations.

5 For this muscular apparatus, see Cuvier , loc.
cit. PI. III. fig. 3-5, and Anat. comp. V. p. 9
(Octopus) ; and Otoen, loc. cit. (Nautilus).

6 Needham , Nouv. l)ecouv., loc. cit. p. 28, PI.

III. fig. 1 ; Brandt , loc. cit. p. 305, XXXII. fig.
6-10 ; Savigny , loc. cit. PI. 1. 5 F'erussac, loc. cit.
Octopus , PI. III. Argonauta , PI. IV. Sepia , PI.

IV. ; Owen , On the Nautilus, p. 22, PI. VIII. fig.
6, 7, or Isis, p. 19, Taf. II. or Ann. d. Sc. Nat p.
113, Pi. IV.; and Valenciennes , loc. cit. p. 280,
PI. X. fig. 3, 4.

286

THE CEPHALOPODA.

$ 250.

thelium. It begins behind the pharynx by a straight, long, very narrow
oesophagus, whose internal surface is longitudinally plicated. After leaving
the annular opening of the cephalic cartilage, it enters the peritoneal cavity,
which is highly developed and divided by constrictions into several cham-
bers. With the Loligina, the oesophagus is of uniform calibre throughout
to the stomach ;(1) 2 3 4 but with the Octopoda, it is abruptly dilated, upon leav-
ing the cephalic cartilage, into a kind of crop, which extends to the stom-
ach.® With Nautilus, also, it is dilated, but gradually, into a very large
crop, which communicates with the stomach by a narrow, short canal.®

The Stomach invariably consists of a sac lined with a very solid epi-
thelium, which is plicated longitudinally ; the Cardia and Pylorus axe
situated close to each other at its upper portion.® As soon as the intes-
tine has left the pylorus, it forms a Caecum which has glandular, plicated
walls, and, with many genera, is more or less elongated and spirally
convoluted.® The rest of the intestine is short, rarely fiexuous, and ex-
tends from the peritoneal sac to the base of the funnel,® where it termi-
nates in a small anal prolongation, the borders of which are often fringed ;
sometimes it has two lateral tongue-shaped valves, placed opposite each
other, and by which the anal opening can be closed.®

§ 250.

The Salivary organs of the Cephalopoda are highly developed, and
consist of a superior and an inferior pair, the former of which is some-
times, but the latter very rarely, wanting. The superior pair consists of
two glandular lobes situated at the posterior extremity of the pharynx,
which open by short excretory ducts behind the root of the tongue.®
The inferior pair lies on each side of the oesophagus at the upper portion
of the peritoneal sac, directly behind the cephalic cartilage. These
organs, usually of a dull-white color, are composed of numerous inter-

1 Sepia , Loligo , Onychoteuthis , Loligopsis ,
Sepiola , &c.

2 Cuvier , Mem. PI. IV. fig. 1, 2, b.$ Wagner ,
Icon. zoot. Tab. XXIX. fig. 14 ( Octopus ); Van
lieneden , loc. cit. PI. III. fig. 3, cl. (Argonauta) j
FSrussac , loc. cit. Octopus , PI. XIII. fig. 9, 10,
Argonauta , PI. I5, fig. 1, 2 j and Delle Chiaje ,
Descriz. Tav. XV. fig. 3 ( Tremoctopus ).

3 Owen , On the Nautilus, PI. IV. or Isis, Taf.
III., or Ann. cl. Sc. Nat. PI. II. fig. 1.

4 See the figures in Cuvier , Brandt, Ftrussac,
Owen , &c. The stomach of Octopus and Eledone ,
from its muscular walls, and its almost horny
epithelium, resembles very much the gizzard of
birds.

o This caecum, regarded as a second stomach by
many zootomists, corresponds, probably, to the py-
loric appendages of fishes. With Nautilus , it is
a round sac, the internal surface of which has
longitudinal folds, so that its cavity has a lamel-
lated appearance (Owen, On the Nautilus, p. 25,
PI. IV. y. and PI. VIII. fig. 8, f., or Isis, Taf. II.
III., or Ann. d. Sc. Nat. PI. II. fig. 1, y. PI. IV.
fig. 8, f.). With Loligopsis, and Sepiola , this
round sac is lined internally with spiral folds
(Grant, Transact, loc. cit. p. 25, PI. II. fig. 7, g.
and p. 81, PI. XI. fig. 7, 8, c.). With Sepia, and
various Octopoda, it is oblong, and lined internally
with transverse spiral folds supported by a kind
of mesentery 5 — see Van Beneden, loc. cit. PI.

III. (Argonauta) ; Delle Chiaje, Descriz. Tav.
XIII. XV. XVIII. (Tremoctopus. Sepia, and
Loligo) ; Cuvier, Mem. PI. IV. fig. 1, 2, f.: Wag-
ner, loc. cit. fig. 14, f. (Octopus) Home, Lect. on
Comp. Anat. PI. LXXXIII. (Loligo sagittate) ;
and Firussac, loc. cit. Put, in this respect, Loligo
vulgaris forms an exception ; its caecum is
straight, oblong, and its thin walls are without in-
ternal plicae : see Meckel, Syst. d. vergleich.
Anat. IV. p. 199, and Delle Chiaje , Descriz. &c.
Tav. XVI. fig. 5, s.

6 The intestine is straight with Argonauta ,
Loligo, Sepia , Sepiola, n,nd other Loligina 5 but
it ia fiexuous with Octopus , Eledone , and Nau-
tilus.

1 Owen (Transact, of the Zool. Soc. II. Pi. XXT.
fig. 16) has found two lateral valves projecting into
the anal cavity with Sepioteuthis. I have seen
two similar with a Tremoctopus. Rat like (M£m.
de St. Petersburg, loc. cit. p. 160 PI. II.) has
found them replaced, with Loligopsis, by two
tentaculiform prolongations.

1 Cuvier, M4m. p. 27, PI. III. fig. 3, e. (Octo-
pus) ; Fdrussac, loc. cit. Octopus, PI. XII. fig. 6.
n. PI. XIII. fig. 9, n.*, Owen , Cyclop. I. p. 532,
fig. 218, i. (Onychoteuthis). With Nautilus ,
Owen found no lower, and only the traces of the
upper glands (On the Nautilus, p. 23, PI. VIII. fig.
7, g., or Isis, p. 20, Taf. II., or Ann. d. Sc. Nat. p.
114, PI. IV. fig. 7, g.).

THE CEPHALOPODA.

§ 250.

287

anastomosing glandular tubes, forming, sometimes, several lobes, and
sometimes, a single triangular mass with a smooth exterior.

In their passage in front, the two excretory ducts converge and form,
under the oesophagus, a common canal which traverses the pharynx and
terminates in the mouth near the root of the tongue.®

The Liver is generally of a reddish-yellow color, and is rarely lobulated.
Usually, it is a compact glandular mass capsulated by a fold of the peri-
toneum.® With the Octopoda, it is a large, smooth, ovoid gland,® while
with the other Cephalopoda, with a few exceptions,® it is divided into two
or four portions symmetrically surrounding the oesophagus.® The bile,
when this organ is single or double, is excreted bv two ducts arising from
the inferior extremity of the organ ; but when this organ is quadruple, as
with Nautilus , and Loligopsis, each division has a special excretory duct,
and all these ducts soon unite into a common Ductus ckoledockus, which,
after a short course, opens upon the sides of the coecum.®

As a Pancreatic gland may, certainly, with reason, be regarded the
pale-yellow, short, ramified glandular tubes, which, with many species, are
appended to the hepatic ducts with which they communicate by many
orifices. ®

2 For the intimate structure of these glands which
appear to be wanting with Nautilus , and Loli-
gopsis, see J. Muller, De Gland, struct, p. 54,
Tab. V. fig. 9. They are lobulated with Loligo,
and consist only of a small compact body with
Octopus, Eledone, Sepia, k c •, see Cuvier, M6m.
PI. III. fig. 2, 3 ; Wagner, Icon. zoot. Tab. XXIX.
fig. 14, k.; Brandt, loc. cit. Taf. XXXII. fig. 3, 5 ;
i'cr tissue, loc cit. Octopus , PI. XII. XI LI. Their
surface is granulated with Sepiola, according to
Delie Chiaje , Descriz. Tav. XXVI. fig. 14, L.,
and Grant, Trans. &c. PI. XI. fig. 8, g.

3 For the intimate structure of the liver, see
Muller, De Gland, struct, p. 71 (Octopus), and
Hat Ilk d, loc. cit: p. 137 ( Loligopsis ).

I See Cuvier, Wagner , and Ferussac , loc. cit.

5 With Onychoteuthis Banks ii, the liver is a
single, very oblong mass ; see Owen, in the Cy-
clop. I. p. 537.

(» With Nautilus, the liver is divided into four
large portions, each composed of numerous lobes
embracing on each side the crop-like oesophagus *,
see Owen , On the Nautilus, p. 26, PI. IV. z., or
Isis, p. 22, Taf. III., or Ann. d. Sc. Nat. p. 117,
PI. II. fig- 1. is. With Loligopsis guttata, the
four hepatic divisions are, according to Grant
(Trans. &c. p. 25, PI. II. fig. 4, e. and 7, a.), deeply
concealed in the cavity of the body ; while with
Loligo Eschscholtlzii, and dubia, it is a single
mass, according to Rathki (Mem. de St. Petersb.
loc. cit. p. 137, 170. PI. II.). With Sepia, Loligo,
Sepiola , &c., this organ is divided into long halves,
smooth externally, and extending from the neck
along the dorsal median line, their length depend-
ing on that of the animal ; see Brandt, loc. cit. Taf.
XXXII. fig. 3, i>. (Sepia), and Grant , loc. cit. PI.
XI. fig. 7, 8. f. (Sepiola).

1 See Cuvier, Mem. p. 30, PI. IV. fig. 2, 4, n.
n.*, Firussac, loc. cit. Octopus, PI. XIV. fig. 5, 6,
Jr gonauta, PI. I5, fig. 2, d.; ,Owen , On the Nau-
tilus, PI. VIII. fig. 8, h., or Isis, Taf. II., or Ann.
d. Sc. Nat. PI. IV. fig. 8 h.; and Grant, Trans,
of the Zool. Soc. I. PI. II. fig. 7, b. PI. XI. fig. 7,
g. (Loligopsis and Sepiola).

8 This structure and arrangement of the glandu-
lar appendages of the hepatic ducts> which were
noticed and regarded as a pancreas by Hunter
(The Catal. of the Physiol Ser. I. p. 229, No. 775)
with Sepia, remind one very much of what is found
in fishes, where, according to S tannins' inves-
tigations, the pyloric appendages communicate
with the Ductus choledochus (see Brockmann
(Stannius) De Pancreate piscium, Diss. Ilostoch.
1846).* According to Delle Chiaje (Descriz. I.
p. 32, Tav. XIII. XVII [.), these bodies exist not
only with Octopus , Eledone, Tremoctopus, and
Ar gonauta , but also with Sepia, Loligo, and Se-
piola. Grant (The Edinb. Philos. Jour. XIII.
1825, p. 197) has described them with Loligo sa-
gitta, and Owen sought in vain for them with
Nautilus, but found them highly developed with
Sepiola, Onychoteuthis, Sepioteuthis, and Ros-
sia (Cyclop. 1. p. 537). See also Grant, I. Trans,
of the Zool. Soc. I. PI. II. fig. 7, c., PI. XI. fig. 7,
8, 13 (Loligopsis and Sepiola).

In the species of Loligopsis examined by
Rathkd (loc. cit. p. 160, PI. II.) the Ductus chole-
dochus was dilated into a round sinus at the point
where the pancreatic tubes opened into it.

* Note. These recent researches modify essentially what
Stnnnius has said in the second volume of his work, upon
the Appendices pijloricne and the Pancreas of fishes, —
organs not in the least identical.

288

THE CEPHALOPODA.

§§ 251. 252.

CHAPTEE Y 1 1 .

CIRCULATORY SYSTEM.

§ 251.

The circulatory system of the Cephalopoda does not appear more highly
developed than that of the other Mollusca.(1) However, this subject is still
deficient in creditable observations, and especially in those relating to the
absence of completely-closed vessels.

The blood is usually colorless, or of a green-bice, or violet-bice color, and
contains, proportionably, numerous round corpuscles enclosing many gran-
ules most of which are colorless, but with a few, scattered here and there,
of a violet hue.®

§ 252.

The Central organ of the circulation consists, with all the Cephalopoda,
of a simple ventricle, situated in the centre of the cavity of the body, and
surrounded with a pericardium. It is round, or oblong, (1> and serves as an
aortic heart.

With Nautilus (Tetrabranchiata), this organ receives, on each side,
two branchial veins ; while with the Dibranchiata there is one vein
only, and the heart sends off a superior and an inferior aortic trunk.® The
mouth of the veins and the origin of the arteries are furnished with
valves.® The Ascending aorta first sends two branches to the mantle,
then gives off branches to the liver, to the upper portion of the digestive
canal, to the inferior salivary glands, and to the funnel. Behind
the cephalic cartilage it bifurcates, forming a ring embracing the
upper extremity of the oesophagus, and from which arise two arteries for
the ocular bulbs,® eight or ten for the arms, and many small branches
for the parts of the mouth.® The Descending aorta furnishes branches to

1 See Milne Edwards , and Valenciennes ,
Compt. rend. XX. 1845, p. 261, 750, or Froriep's
neue Notiz. XXXIV. p. 84, 258 *, also Milne
Edwards , Ann. d. Sc. Nat. III. 1845, p. 341.
This last author has also described (Ann. d. Sc.
Nat. VIII. p. 53), the circulatory system of the
Loliglna, which is interrupted by a large sinus ;
but he makes no mention of the aquiferous system.
As of late there is increasing evidence for the
opinion, that, with various invertebrate animals,
the blood-system communicates externally at cer-
tain points on the body, and can therefore receive
water into its interior, it is now important to inves-
tigate the direct or indirect relations between this
and the aquiferous system which is so widely
spread through the Mollusks, the Worms and the
Zoophytes. It may be that this aquiferous system,
if it really communicates with the blood system,
corresponds to a lymphatic apparatus, although it
seems hardly reasonable to suppose that canals,
which carry a portion of the nutritive fluids, should
open externally.*

- Wagner, Zur vergleich. Physiol, d. Blutes.
lift. I. p. 19 ; and Delle Chiaje , Descriz. I. p. 57.

1 The form of the heart depends upon that of the

* [ § 251, note 1.]

(Octopus). — Ed.

posterior part of the body *, it is large in the gen-
era with a short body, and elongated in those of a
long body. According to Kolliker (Ann. of Nat.
Hist. XVI. p. 414), Hectocotylus has also a
heart communicating with arteries and veins, but
he says nothing of its locality.

2 See Owen, On the Nautilus, PI. VI. fig. 1, or
Isis, Taf. IV. or Ann. d. Sc. Nat. XXVIII. PI. III.
fig. 2 •, Brandt, loc. cit. Taf. XXXII. fig. 22 ; The
Catal. of the Physiol. Ser. II. PI. XXII. (Sepia) ;
and Van Beneden, loc. cit. PI. III. fig. 5 (Ar-
gonauta).

Often the two branchial arteries are widely di-
lated before entering the heart, and these dilata-
tions may be regarded as auricles.

3 See Cuwier, M6m. p. 22, PI. II. fig. 4 (Octo-
pus) ; and Owen, Cyclop. I. p. 541, fig. 227
(Onychot euth is).

I For the distribution of the ophthalmic arteries
see Krohn, Nov. Act. Nat. Cur. XIX. pt. II. p.
47.

5 Delle Chiaje, loc. cit. Tav. LXXXVIII. XC.
XCII. XCIV. (or 20, 28, 22, 24) has represented
in detail the arterial system of Octopus vulgaris,
Sepia ojjicinalis, Loligo vulgaris and sagittata.

For Milne Edwards ’ beautiful figures see R<*gne anim. loc. cit. PI. 1' , 1

§ 252.

THE CEPHALOPODA.

289

the stomach, the small intestine, the rectum, the branchiae, and the genital
organs ; the artery of these last, however, sometimes arises directly from the
heart.

Nothing positive can now be said as to the terminal relations of these
arteries ; — that is, whether they are directly continuous with the venous
radicles by means of a capillary system with proper walls, or whether they
terminate by orifices so that the blood is effused immediately into the paren-
chyma of the body.®

The Venous system begins in the different parts of the body by numer-
ous small vessels, of which we are still ignorant whether they are continu-
ous with the terminal arterioles, or whether they commence by themselves
with proper orifices. Their radicles unite and form longer branches which
finally open into a large Sinus. One of these sinuses, which is of a circular
form, surrounds the upper extremity of the oesophagus, and receives the
veins coming from the eyes, the arms,® and the parts of the mouth. From
this sinus arises another, of an oblong form, which, since it extends into
the cavity of the body and receives the different veins from the viscera,
may be called a Vena cava superior. In the centre of the body it divides
into two large venae cavae which extend on each side to the base of the
branchiae® and terminate in the two so-called branchial hearts.® These
two veins receive, also, two trunks, which bring the blood from the mantle
and are often dilated into two large sinuses. <10)

The distinct, but often very thin walls of the venous sinuses, are some-
times so intimately blended with the adjacent organs, that these sinuses may
be easily taken for wall-less lacunae. (11)

6 Milne Edwards and Valenciennes (loc. cit.)
throw no Light on these questions. It is moreover
singular that in the numerous and often very de-
tailed figures of Delle Chiaje of the vascular sys-
tem of Cephalopoda, he has nowhere represented
in the least a capillary net-work between the arte-
ries and veins 5 while Kolliker (Entwick. der Ce-
phal. p. 81), declares that he has seen numerous
oapillary vessels in the embryos of Sepia.

7 All the arms of the Cephalopoda have two
venous trunks. Lebert and Robin ( Muller’s
Arch. 1846, p. 130) have observed, in the venous
system Sepia officinalis, a valve preventing the
reflux of the blood towards the head.

8 With Nautilus , this sinus is divided into four
venae cavae {Owen, loc. cit.).

9 The so-called Branchial hearts of the dibranch-
iate Cephalopoda have no muscular fibres, but
have a very glandular aspect, and are in close re-
lation with the urinary organs 5 see below, § 255.

10 Delle Chiaje, loc. cit. Tav. LXXXVIT.
LXXXIX. XCI. XCIII. (17, 27, 21, 23), has also
figured with many details the venous system of
Octopus , Sepia, and Loligo.

11 It is, therefore, difficult to decide if the large
cavities which Milne Edwards (Ann. d. Sc. Nat.
III. loc. cit. PI. XIII.-XVI.) has injected, were di-
lated veins or simple lacunae. In this last case,
the venous system would communicate directly with

25

the cavity of the body, and there are many circum-
stances in favor of this view. It is, therefore, to be
regretted that Milne Edwards did not, in his re-
searches, pay more attention to the aquiferous sys-
tem which is spread through the whole body of
the Cephalopoda, and thus, for the present at
least, prevent the objection, that these aqueous
reservoirs should be confounded with the venous
sinuses. The lymphatic reservoirs which, according
to Erdl ( Wiegmann's Arch. 1843, I. p. 163) sur-
round, and can be injected by means of the arteries,
are also, perhaps, venous sinuses. An observation
of Owen (On the Nautilus, p. 27, PI. YI. fig. 1,
No. I1, or Isis, p. 24. Taf. IV. or Ann. d. Sc. Nat. p.
121, PL III. fig. 2, No. I1), and of Valenciennes
floe. cit. p. 287), that the large superior vena cava
communicates with the abdominal cavity by nu-
merous orifices, is of much importance. For, in this
way, this vein must be regarded as a large blood-
reservoir, conducting, very probably, the nutritive
fluid, after its transudation through the intestinal
canal, into the general blood current.

The pericardium of the Cephalopoda sustains,
perhaps, analogous relations to the blood-system,
for, with Nautilus, it is said to communicate with
the abdominal cavity, and with the principal vena
cava, with the other Cephalopoda 5 see the conclud-
ing paragraph of note 1, § 251.

290

THE CEPHALOPODA.

§ 253.

CHAPTER VIII.

RESPIRATORY ORGANS.

§ 253.

All the Cephalopoda respire by means of Branchiae. These are situ-
ated in the cavity of the mantle, separated from the other viscera, and out-
side of the peritoneum. Hectocotylus forms the only exception in this
respect, — its branchiae being free, and placed along the sides of the ante-
rior half of the body under the form of numerous oblong, thin, thickly-
set lamellae. (1) 2 3 Nautilus has, on each side, two branchiae, while the other
Cephalopoda have only one.

These organs have a more or less oblong, pyramidal form, and are
attached, at one of their borders, to the external surface of the mantle by
a thin cutaneous fold, — leaving their extremity to extend freely in front.
The adherent edge is bordered by the trunk of the branchial artery, and by
a large glandular band,® while the free border is occupied, from its base
to the top, by the principal branchial vein. With Nautilus , and the Loli-
gina, there are, between these vessels, numerous, triangular, branchial lam-
ellae lying upon each other, and plicated upon both surfaces. But with
the Octopoda, these lamellae are replaced by arches, which, on each side,
pass from one vascular trunk to another, and have, upon their convex edge,
a multi-plicated membranous band.® The branchial vessels extend from
the branchial artery to the branchial vein through the lamellae and the
branchial arches;® and in this passage, the venous is changed to arterial
blood.® As there is no ciliated epithelium on the surface of the branch-
iae, the water is renewed exclusively by the rhythmical respiratory move-
ments.® It enters, from both sides of the funnel, into the interior of the
mantle when its borders are open, and is ejected through the funnel by the
contractions of the mantle when its borders are closed.®

1 I have found such with Hectocotylus tremoc -
topodis ; according to Kolliker (loc. cit.) that of
Argonauta has also branchiae.

2 This glandular body has been regarded by
Cuvier (Mem. p. 20, PI. II. fig. 3, PI. III. fig. 1,
A.) and other zootomists as a muscular stripe;
while Mayer (Analekten, &c., p. 56, Taf. V. fig.
1, No. 14), from its cellulo- vascular texture, has
taken it for a spleen. I have been unable to find in
it any muscular fibres, but only numerous cells, and
I am of the opinion that this enigmatical organ
holds some special relations with the venous system.

3 See Owen, On the Nautilus, p. 30, PI. YI. fig.

I, 2, or Isis, p. 26, Taf. IV., or Ann. d. Sc. Nat. p.
124, PI. III. fig. 2, 3, and Valenciennes , loc. cit.
p. 281, PI. IX. X. ; The Catalog, of the Physiol.
Ser. II. PI. XXI. XXII. (Sepia)-, Treviranus ,
Beobacht. aus. d. Zoot. u. Physiol, p. 37, Taf. VIII.
fig. 52-54 ; Grant , Transact, of the Zool. Soc. I. PI.

II. XI. ( Loligopsis and Sepiola) ; Cuvier , M6m.
p. 20, PI. II. III.; Delle Chiaje , Descriz. Tav.
XIX. fig. 1-5 (Octopus); and Ftrussac, loc. cit.

4 The number of the branchial lamellae and
arches varies very much. With Nautilus , each
branchia is composed of a double row of forty-eight
lamellae ; the long-bodied Loligina have a double
row also, composed of sixty to ninety lamellae.
W'ith Sepia , there are thirty pairs ; and with the
Octopoda, the number of branchial arches is still
less ; there are only fifteen pairs with Argonauta ,
and twelve alone with Octopus , and Eledone.

5 For the distribution of the blood-vessels in the
branchiae of Sepia , see Tilesius , De Respirat. Se-
piae officinalis, Tab. I. II.

<> That, with the Cephalopoda, which are in gen-
eral so poor in cilia, there should be no ciliated
epithelium on the branchiae, is so remarkable a
fact, that I have had it confirmed from fresh speci-
mens by my friend H. Koch at Trieste, although
Sharpey (Cyclop. I. p. 619) had already spoken of
it.

" For these respiratory movements, see Grav -
enhorst , Tergestina, p. 1, and Wagner , in tho
Isis, 1833, p. 159.

$$ 254, 255.

THE CEPHALOPODA.

291

§ 254.

The existence of an Aquiferous system with the Cephalopoda cannot be
doubted.® It occupies the entire trunk of these animals, and terminates by
two orifices between which lies the excretory duct of the ink-sac, and which
are often situated upon a small tubular eminence of the peritoneum. Each
of these orifices leads into a spacious, thin-walled cavity (lateral cell),<2)
situated near the pericardium. It contains the two venae cavae with their
appendages, and communicates, by orifices and canals, with other aquiferous
cells surrounding the various viscera, — such as the stomach and the caecum,
as well as with the two so-called branchial hearts. These cells send a
canal to the special genital glands.®

With Nautilus, there are, on each side, in the abdominal peritoneum,
three orifices, through which the water of the cavity of the mantle enters
into the lateral cavities.® There is another system of aquiferous canals
under the skin of the head and neck. It consists of several large reservoirs
which extend somewhat deeply between the organs of this portion of the
body. These reservoirs communicate externally by orifices situated upon
different points of the head.®

CHAPTER IX.

ORGANS OF SECRETION.

I. Urinary Organs.

§ 255.

The Urinary organs of the Cephalopoda, which have hitherto been much
doubted, are particular appendages of the Venae cavae. With all the
species having two branchiae, the two Venae cavae, formed by the division
of the great median sinus, and which extend obliquely through the two lat-

1 For this aquiferous system, see D'Orbigny ,
in Fdrussac, loc. cit. Introduct. p. 20, Ouvertures,
aquif^res, and Delle Chiaje , Descriz. I. p. 53,
Apparato-acquoso o idro-pneumatico. Both of
these naturalists have included in this system the
lachrymal openings and the space circumscribed by
the ocular capsules.

2 See Swammerdamm, loc. cit. p. 354, Taf. LI.
fig. 1, q. q, and Taf. LII. fig. 10, g. g ; Brandt ,
Media, zool. II. p. 30S, Taf. XXXII. fig. 1, 24, i. i
(Sepia) ; Cuvier , Mem. p. 15, PI. I. fig. 1 r. r, and
Mayer, Analekt. &c. p. 54, Taf. Y. fig. 1. t. u.
(Octopus) ; Savigny , loc. cit. PI. I. fig. 12, 3i : g. g
(Octopus and Sepia), and Fdrussac , loc. cit. ( Oc-
topus), PI. XII. fig. 1. PI. XIII. fig. 2, PI. XIY.
fig. 1, f. f r. r. See also Krohn. in Muller's Arch.
1839, p. 353.

3 j Delle Chiaje , Descriz. Tav. XV. fig. 1. q.
(Tremoctopus).

4 Owen , On the Nautilus, p. 32, or Isis, p. 27, or
Ann. d. Sc. Nat. p. 127, and Valenciennes , loc.
cit. p. 285, PI X. fig. 1, 2.

5 With Tremoctopus violaceus , there are four
very distinct Foramina aquifera. Two of these
are situated at the superior part of the head behind
the base of the superior arms, and the other two on
the sides of the funnel (Delle Chiaje , loc. cit. Tav.
LXXI. (11) fig, 10, p., Fdrussac , loc. cit. p. 92.
Octopus , PI. XVIII. XIX. fig. 1). With Octopus
tuberculatus , there are only these last two open-
ings (Delle Chiaje , loc. cit. Tav. LV. (3), fig. 1, d.
d. 5 Wagner , in Heusinger's Zeitsch. f. d. organ.
Physik. III. p. 227, Taf. XII. fig. 1, and Fdrussac.
loc. cit. p. 88, Octopus , PI. VI.1 2 3 4 fig. 2).

It is the same also with Ommastrephes todarus
(Ferussac loc. cit. Ommastrephes , PI. II. fig. 3,
10). With Octopus indicus , there are eight small
aquiferous orifices between the arms near the mouth
( Fdrussac , loc. cit. p. 25, Octopus , PI. XXVI. fig.
1). According to D'Orbigny , there are only six,
in the same situation with Sepia , Loligo , Onycho-
teuthis , &c.

292

THE CEPHALOPODA.

§ 255.

eral aquiferous cells to the base of the branchiae, have, exteriorly, variously
ramified, glandular tufts which project into the aquiferous cells. (1) Some-
times similar appendages are found also upon the principal veins which
open, in these cells, into the venae cavae.® With Nautilus , which has
on each side in the peritoneum four venae cavae, each of these last extends
between two cells each of which receives a part of the glandular append-
ages with which it is provided.®

These organs, for a long time known as the Spongy bodies, can now be
regarded positively as kidneys; for, by chemical analysis, it has been
proved that they secrete uric acid.(4) Careful examination of them has
shown that their parenchyma consists of a tissue of contractile fibres,®
among which are spread branches coming from the venae cavae.

This parenchyma is surrounded by a structureless membrane, covered with
several layers of nucleated granular cells. The urine is secreted from the
external surface of this cellular layer ; it is of a dirty-yellow color, and
escapes immediately into the peritoneal cavities, and thence is discharged
externally through their orifices, which may, therefore, be taken for ure-
thral canals. These spongy appendages of the veins ought, therefore, to
be regarded as everted glandular follicles, the secreting cells being situated
externally and the blood-vessels within.® Not unfrequent.ly, the reddish
crystals formed in the urine, completely incrust these glands, giving them
their peculiar color.®

The so-called Branchial hearts of the Dibranchiata contain no trace of
muscular fibres, and appear to be in some way connected with the urinary
organs. They are round, hollow, thick-walled, and lie upon the course
of the venae cavae between the last renal masses of the branchiae, so that
the blood of these veins passes into their cavities and bathes their spongy
walls.® Their color is violet with the Octopoda, and pale-yellow with the

1 Cuvier, Mem. p. 18, PI. II. fig. 1, 3, PI. III.
fig. 1, x. x *, Wagner, Icon. zoot. Tab. XXIX.
fig. 14, q. q, 16 •, Delle Chiaje , loc. cit. Tav.
LXXXYII. XCI. XCIII. XCIX. (17, 21, 23, 19) •,
Carus , Erlaiiterungstafeln, lift. YI. Tab. II. fig. 15,
17 m, Mayer , Analekten, Taf. Y. fig. 1, s. s. ( Octo-
pus]) ; Grant , Transact, of the Zool. Soc. T. PI. II.
fig. 8, a. b, PI. XI. fig. 9, b. b. ( Loligopsis and
Sepiola ) ; Van B.cneden , loc. cit. PI. III. fig. 5, f.
f. ( Argonauta ).*

*2 Krohn, in Muller's Arch. 1839, p. 355, and
Brandt , loc. cit. Taf. XXXII. fig. 2. x.

3 Owen, On the Nautilus, p. 31, PI. V. No. 6,
PI. YI. fig. 1, No. 6, or Isis. p. 26, Taf. III. IV., or
Ann. d. Sc. Nat. p. 126, PI. III. fig. 1, 2 ; and Va-
lenciennes, loc. cit. p. 286, PI. X. fig. 2, Tt.

4 These appendages have been successively re-
garded as absorbent vessels, a rudimental portal
system, a spleen, accessory branchiae, blood-reser-
voirs, genital organs, &c. Mayer (Analekt. &c.
loc. cit. p. 54) was the first to regard them as uri-
nary organs, but this view was not commonly re-
ceived. The two peritoneal cavities containing
these organs, were also taken by him for urinary
bladders, and their orifices as urethrae. The same
function has also been attributed to these organs
by Savi (Atti della terza riunione degli scienziati

* [ § 255, note 1.] See also Milne Edwards,
Rdgne anim. loc. cit. PI. Ie. r. (Octopus). — Ed.

t [ § 255, note 6.] For this communication in
full with figures of Harless, see Wiegmann's Arch.

tenuta nel Firenze, 1841, p. 396, pr Isis, 1843, p.
417).

At my request, E. Harless , while at Trieste, sub-
jected these organs to a chemical analysis, and, as
he obtained from their contents purpurate of Am-
monia, there can be no doubt that they are really
kidneys.

•5 The contractility observed in these appendages
is due, without doubt, to this fibrous tissue (Krohn,
in Froriep's neue Notiz. XI. 1839, p. 214, and
Erdl , in Wiegmann's Arch. 1843, p. 162).

<* 1 am indebted for this remarkable histological
fact to a recent communication from Harless.]

I I have often found in the kidneys of the Sepia
officinalis groups of rhomboidal crystals of a crim-
son red color. Krohn ( Froriep's neue Notiz. XI.
p. 215) has found them constantly with Sepia, but
has sought in vain for them with Octopus, and
Loligo vulgaris.

8 The so-called branchial hearts, which are want-
ing with Nautilus, and which, it is supposed, pour
the blood into the branchiae with the other Cephal-
opoda, are surrounded by a smooth peritoneal en-
velope, and have, internally, a cavernous aspect 5
see Cuvier , Mem, PI. II. fig. 3, No. 9 (Octopus) ;
Carus, Erlaiiterungstaf. lift. VI. 1843, Tab. II. fig.
181. (Sepia). With the Loligiua, a constriction sit-

1847, p. 1, Taf. I. His chemical, as well as his his-
tological results, can leave little doubt as to the Re-
nal nature of these organs. — Ed.

\

256, 257.

T1IE CEPHALOPODA.

29;

Loligina. Their Avails are composed of a dense web of cells, which, with
the Octopoda, contain round, violet nuclei, of a crystalline texture and
resembling entirely those found in the renal cells of the Gasteropoda/9'

II. Organs of Special Secretions.

§ 256.

The Ink-sac is an organ generally common with the Cephalopoda. It
is usually pyriform, situated upon the median line of the abdomen, and
often enveloped with a peritoneal layer of silvery lustre.01 Its apex points
forwards and upwards, towards the funnel. The walls of its generally small
cavity are cavernous/2' and secrete the well-known black pigment, Avhich,
through contractions, passes into the funnel, and is then expelled, mixed
with the water of the sea, which is passing out of the body. The excretory
duct of this sac runs along the rectum, and terminates just behind the anus,
or opens into the rectum.®

As an organ, also, of special secretion, ought to be regarded the com-
pletely-closed chambers found in the shell of the Nautilina ; for it is said
that their walls, like those of the natatory bladder of fishes, secrete a gas/4>

CHAPTER X.

ORGANS OF GENERATION.

§ 257.

The Genital organs of the Cephalopoda are always distributed upon two
individuals, and present very remarkable peculiarities.

uated at the inferior or lateral portion, separates
these bodies into two unequal divisions ; see Brandt ,
loc. cit. Taf. XXXII. fig. 22, q. r. •, The Catal. of
the Physiol. Ser. II. PI. XXII. f. x. (Sepia) ; Delle
Chiaje , loc. cit. Tav. XCI. XCIII. XCV. XCVI.
(21, 23, 25, 26), (Loligo and Sepiola).

9 Erdl ( Caras , Erlauterungstaf. lift. VI. p. 7)
has published an observation on the glandular na-
ture of these bodies, and the resemblance of their
parenchyma with that of the kidneys of Helix , all
of which I have been able to fully confirm. Nev-
ertheless, these organs demand further chemical
and histological investigation.

I This organ, which is entirely wanting with
Nautilus , and Hcctocotijlus , has an elongated
form with the long-bodied species, and is large
with those whose body is short ; see Wagner , Icon,
zoot. Tab. XXIX. fig. 20, h. i. (Octopus) ; Ferus-
sac, loc. cit. Argonauta , PI. I.5 fig. 2, 3 •, Brandt ,
loc. cit. Tab. XXXII. fig. 1, 24, o. (Sepia). That of
Sepiola is quite remarkable in having an extraor-
dinary development in certain individuals, at par-
ticular seasons, without reference to the sexes.
There are then found two long bodies adherent by a
constriction to the sides of the otherwise simple ink-
sac. These lateral bodies are black, composed of a
glandular tissue continuous with that of the sac,

and surrounded by a muscular layer. Peters
(Muller's Arch. 1842, p. 329, Taf. XVI. fig. 1, b.
b. 8-10) has seen it contract regularly. With the
specimens preserved in alcohol the ventral surface
appears colorless. Grant appears to have been un-
aware of this increased development at certain
times with Sepiola , for he has attributed to them
in general a trilobed ink-sac (Transact, of the Zool.
Soc. I. p. 82). In the Sepiola figured by Delle
Chiaje (Descriz. Taf. XI. fig. 4, 1.), the two lateral
lobes in question are very distinct.

2 Delle Chiaje , Descriz. I. p. 74, Tav. XIII. fig.
1, 2. Tav. XVIII. fig. 4 (Loligo, Octopus and
Eledone).

3 This last case obtains with the Loligina.

4 Owen (On the Nautilus, p. 47, or Isis, p. 39)
has, it is true, left undecided the question whether
these chambers are filled with gas or with liquid •,
but, according to Vrolik (Ann. of Nat. Hist. XII.
p. 174) the chambers of Nautilus pompilius really
contain a gas composed chiefly of nitrogen without
any trace of carbonic acid. These chambers resem-
ble, in many respects, the swimming bladders of
fishes, and, like them, serve, perhaps, to facilitate
the ascension and descension of these animals in
the water.

294 THE CEPHALOPODA. * § 258.

The Eggs, at their escape from the ovary, are oval, and have a yellow, or
rose-colored vitellus, containing a germinative vesicle and dot.

The vitelline membrane has transverse and longitudinal folds on its
internal surface, which extend into the vitellus, — giving the eggs a
reticulated aspect. (1) 2 3

The Spermatic particles are very active, of a cercarian, or a simply
capillary form, and, as a whole, give the sperm a white color. Those of a
cercarian form are proper to the Loligina, and consist of a cylindrical
body to which is rather abruptly attached a small and pretty long tail.®
Those of a capillary form are found with the Octopoda, not only with the
males of Octopus and Eledone, but also with Hectocotylus.{3)

§ 258.

The Ovary, always simple, is situated, at the base of the sac of the
mantle, in a solid envelope (ovarian capsule) of a round or oblong form,
and derived from the peritoneum. At its circumscribed point the proper
ovary commences as a multi-lobulated body filling its cavity.® The eggs,
which are developed in the parenchyma of these lobes, appear first as round
prominences ; they gradually increase, and, finally, are attached to the ovary
only by a small peduncle. At this epoch the ovary furnishes them with a thin
envelope (egg-capsule), through which, in the mature eggs, the reticulated
folds of the vitelline membrane can be seen.® When the eggs are fully
matured, their capsules burst, and they fall into the ovarian capsule, after
which, their proper capsules fade and finally disappear.® From the ovarian
capsule they pass into the oviduct through an infundibuliform opening ; but,
beside this opening, some Octopoda have also two others belonging to an
aquiferous canal, and which, perhaps, play an important part in the fecunda-
tion of the eggs.(4> The oviduct is simple, or double, and extends directly
in front opening at the base of the funnel near the rectum. With Argo-
nauta, and Tremoctopus, alone, the two female genital orifices are situated,

1 See Kolliker , Entwickelungsgesch. &c. p. 1, 9,
Taf. I. fig. 9-12. These longitudinal and transverse
folds have been observed in the eggs of Sepia and
Sepio/a ; the longitudinal only are found in those
of Argonauta , Tremoctopus , Octopus , Eledone ,
&c.

2 See my Beitrhge z. Naturgeschichte d. wir-
bell. Thiere, in the Neuesten Schrift. d. naturforsch.
Gesellsch. in Danzig. III. 1839, Hft. II. p. 54, Taf.
II. fig. 47 (Loligo); Milne Edwards , Ann. d. Sc.
Nat. XVIII. 1842, p. 337, PI. XII. fig. 6, PI. XIII.
fig. 7 (. Loligo and Sepia), and Peters, in Muller's
Arch. 1842, p. 334, Taf. XVI. fig. 14 ( Sepiola ).

It is easy to observe the development of the
spermatic particles in the testicles. According to
my observations, the daughter-cells in the mother-
cells, are developed into as many spermatic parti-
cles the tails of which rupture one of the thin sides
of the mother-cell.

3 Milne Edwards (loc. cit. PI. XIII. fig. 11, PI.

XIV. tig. 5), has erroneously figured the spermatic
particles of Octopus and Eledone with a very
large body •, for it is only a small button-like en-
largement *, see Valentin, Repert. 1837, p. 140,
and Philippi, in Muller's Arch. 1839, p. 308, Taf.

XV. fig. 11. This last has represented the tail of
that of Eledone too short.

I have found the spermatic particles of Hecto -
cotylus tremoctopodis to be exactly like those of
Eledone.

1 Cuvier, M6m. p. 31, PI. IV. fig. 6, a. b., Van
Beneden , loc. cit. PI. V. fig. 2, a.-, Delle Chiaje,
Descriz. Tav. XIV.-XVI., and Grant , Trans, of the
Zool. Soc. I. PI. II. fig. 9 ( Octopus , Argonauta ,
Eledone, Loligo , and Loligopsis).

2 Delle Chiaje , Descriz. Tav. XV. fig. 15, and
Kolliker, Entwick. &c. Taf. I. fig. 9 (Sepia);
Carus, Eriauterungstaf. lift. V. Taf. II. fig. 9
(Eledone).

3 With Sepia, the dehiscence produces a rent with
irregular borders (Kolliker, loc. cit. p. 13) •, with
Rossia , and Sepiola, a simple round opening,
which, with Nautilus , according to a figure of
Owen's, has crenulate borders, and, according to
Delle Chiaje, is regularly denticulated with Ele-
done ; see Grant, Transact, loc. cit. I. p. 84, PI.
XI. fig. 12, and Owen, Ibid. II. PI. XXI. fig. 18,
also, On the Nautilus, p. 42, PI. VIII. fig. 9, c. c.,
or Isis, p. 35, Taf. III. or Ann. d. Sc. Nat. p. 142,
PI. IV. fig. 9, c. c., and Delle Chiaje , 16c. cit. Tav.
LV. (3) fig. 15.

4 These two aquiferous canals form a communica-
tion between the ovarian capsules and the aquifer-
ous cells surrounding the branchial hearts ( § 250).
They are found with Octopus, Eledone , and Tre-
moctopus ; see Krohn, in Muller's Arch. 1839, p.
357 5 Kolliker , Entwick. &c. p. 11, and Delle
Chiaje , Descriz. Tav. XV. fig. 1, q. (Tremocto-
pus).

§ 258.

TIIE CEPHALOPODA.

295

wide apart, in the region of the base of the branchiae.® When there is
only a single oviduct, it terminates always on the left side.® With most
of the Octopoda, the oviducts, at near the middle of their course, traverse
a round glandular body, the internal surface of which is longitudinally pli-
cated ; from this point to their extremity, they are covered with analogous
glandular folds.® This glandular body is absent with the Loligina, but the
walls of their oviduct become thick and glandular before terminating.® It
is very probable that this glandular apparatus furnishes the materials of the
various envelopes of the eggs after their escape from the ovary.

There is another peculiar glandular apparatus (Nidamental glands) hav-
ing no direct connection with the genital organs, which consists of two hol-
low, pyriform, whitish bodies, situated upon the ink-sac of the female Loli-
gina. These bodies have a lamellated structure and their obtuse extremity
extends forwards; they open near the genital orifice.® Sometimes,
directly in front of these glands, there is another gland, simple or double
(accessory nidamental gland), of a reddish color, lobulated posteriorly, com-
posed of coeca, but apparently without any excretory duct.a0) This whole
glandular apparatus secretes, perhaps, a substance with which the eggs are
coated as they pass from the oviduct, and which serves to glue them to
foreign bodies.

The deposited eggs (spawn) are always surrounded with envelopes and
prolongations of various forms, by which they are bound together and
attached to submarine bodies. Thus, those of Sepia are enclosed, each, in a
black, oval capsule, composed of several horny layers, which is prolonged
at one of its extremities into a short, cleft peduncle, by which the eggs are
attached, singly or in groups, to marine plants ;(11) but those of the Loligina
are united by a colorless gelatinous substance into a chaplet, and are
enclosed, moreover, each, in a special capsule one of the extremities of which
has a small peduncle ; thus arranged, they form large masses floating free

6 With Octopus , Eledone , Tremoctopus , and
Loligo sagittata , there are two oviducts ; see
Cuvier , M£m. PI. I. fig. 1, q. q. PI. II. fig. 1, r. r.j
Mayer , Analekten, Taf. V. fig. 1, i. i. f f.; Ferus-
sac , loc. cit. Octopus , PI. XY. fig. 2, 1. 1.; Car us,
Erlauterungstaf. lift. Y. Taf. II. fig. 7, h. h.$
Wagner, Icon. zoot. Tab. XXIX. fig. 20, m. m.;
Owen , Trans, of the Zool. Soc. II. p. 121, and
Cyclop. I. p. 558. With Argonauta , these two
oviducts are very long and flexuous ; see Delle
Chiaje , Descriz. Tav. XIV. fig. 1, z. 11.5 and Fan
Beneden , loc. cit. PI. Y. fig. 1, 2-, Ftrussac , loc.
cit. Argonauta , PI. I. 4 fig. 2, s. s.*

6 Such is the case with Nautilus pompilius
(Owen, loc. cit.), Loligo vulgaris (Cams, Er-
lauterungstaf. lift. V. Taf. II. fig. 10, m. 1.), Sepia
officinalis, Sepioteuthis, Rossia, kc. According
to Rathkt (Mem. d. St. Petersburg, loc. cit. p. 161,
PI. II. fig. 10. p. q.), the simple oviduct of Loli-
gopsis passes directly to the posterior part of the
body and terminates at the ventral median line
between the two fins.

It is, however, desirable that this remarkable
exception to the general rule should be confirmed
by other anatomists, for Grant (loc. cit.) is wholly
silent upon the course of the oviduct in the females
of Loligopsis which he examined.

1 With Octopus, Eledone, and Tremoctopus ,
each oviduct has such a glandular enlargement,
but it is entirely wanting with Argonauta ; see
Cuvier, Mem. p. 32, PI. IV. fig. 6, g.; Ferus -

sac, loc. cit. Octopus, PI. XV. fig. 9, 10.-, Mayer,
Analekten, Taf. Y. fig. 1, g. h. (Octopus' ; Delle
Chiaje, Descriz. Tav. XV. fig. 1, n. Tav. XVI. fig.
6 ; and Wagner, Icon. zoot. Tab. XXIX. fig. 20, n.
n. (Tremoctopus and Eledone).

8 This is so with Loligo, Sepia , Sepioteuthis ,
Sepiola, kc. ; see Owen, Trans, kc. II. p 121,
PI. XXI. fig. 18, e. (Rossia). With Nautilus, the
very short oviduct has glandular walls in its whole
extent (Owen, loc. cit.).

9 See S wammerdamm,Bih. d Natur. p. 354, Taf.
LII. fig. 10, g. g.; Brandt, loc. cit. p 310, Taf.
XXXII. fig. 25, k. 1., fig. 28-31 (Sepia) ; Delle
Chiaje, Mem. IV. p. 102, and Descriz. 1. p. 37,
Corpi adiposi, Tav. LVIII. (12), fig. 10, a., 11, e.;
Peters, in Muller's Arch. 1842, p. 335, Taf. XV).
fig. 6, f. f. (Sepiola) ; Owen, Trans, of the Zool.
Soc. II. PI. XXI. fig. 18, g. g. (Rossia).

lh With Sepia , and Sepiola , this gland is single,
and divided by deep fissures into three- lobes (see
the figures cited in the preceding note, and Owen .
Trans. &c. loc. cit. PI. XXI. fig. 19, 20); with
Loligo, and Rossia, it is double, and each is di-
vided into two lobes (Owen, Ibid. PI. XXI. fig. 18.
h. h.).

11 Cuvier, Nouv. Ann. du Mus. d’Hist. Nat. I.
1832, p. 153, PI. VIII. fig. 1-4 ; Cams, Erlauter-
ungstaf. lift. III. Taf II. fig. 16 ; Owen (Cyclop,
loc. cit. p. 560, fig. 244), and Kolliker , Entwickel,
&c. p. 14.

I § 258, note 5.] See also Milne Edwards, R^gne anim. loc. cit. PI. lb. 1°. n. (Octopus). — Ed.

296

TIIE CEPHALOPODA.

§ 259.

in the sea.<12) With those of Argonauta and Tremoctopus, the envelope
is composed of a solid, homogeneous, colorless substance, and at their pointed
extremity there is a small filament ; these filaments being entangled to-
gether, the eggs form large botryoidal masses. Argonauta attaches these
bunches to the convex portion of its shell ; a3) but Tremoctopus , with which
these masses are in chaplets, forms them into a staff-like structure, by
means of a tissue, of leathery consistence, secreted for this purpose. (14) With
the other Cephalopoda, the eggs are arranged in tubes or in fillets/15

§ 259.

The simple, round, or oblong, whitish Testicle, is situated, in most
species, at the bottom of the cavity of the mantle. It is surrounded by a
capsule derived from the peritoneum but adherent to it only at one point. It
is composed of numerous ramified cylinders, converging from the periphery
towards the centre, which is occupied by a narrow irregular cavity.

The sperm is formed in the intervals of the cylinders and thence passes
into the deferent canal, which, at its passage from the testicular capsule, is
narrow and very flexuous, but suddenly dilates at its upper extremity, —
where its walls are thick and glandular, and have a longitudinal fold on
their internal surface.

This glandular portion of the Vas deferens receives the orifice of an
equally flexuous caecum, which is probably an organ of secretion ; and
terminates, finally, in a large sac with muscular but thin walls which are
plicated longitudinally. This sac, known as the Bursa Needkamii, is
followed by a fleshy tube ( Ductus ejaculatorius) , which extends directly in
front and projects, as a short penis, into the cavity of the mantle near the
rectum. a)

With the Loligina, and with Octopus , and Eledone, the sperm is not freely
evacuated, but is enclosed in very complicated organs ( Spermatophores ),
which, at the epoch of procreation, accumulate in abundance in the Bursa
Needhamii, and are large enough to be seen with the naked eye. They are
always cylindrical and consist of a homogeneous, colorless, solid tube, round
at the anterior extremity, but at the posterior end, somewhat constricted and
then dilated into a kind of sphere. Each of these Spermatophores contains
two kinds of organs : a very thin sac filled with spermatic particles, and an
apparatus to project these particles outwards.

The Sperm-sac always contains fully-developed spermatic particles
bundled together : it nearly entirely fills the cavity of the tube, through

12 These chaplets are long with Loligo vulgaris ,
and short with Sepioteuthis ; see Burdach , De
quibusd. anim. marin. p. 155, Tab. XII.; Fdrus-
sac , loc. cit. Loligo , PI. X. fig. 1, 1% and Kolliher ,
loc. cit. p. 14.

13 Rang, Magaz. d. Zool. 1837, V. Taf.LXXXVII.
LXXXVIII.; Fdrussac, loc. cit. Argonauta , PI.

1A

14 This body has a peculiar structure, and un-
doubtedly, is made by the animal itself. It is
composed of numerous, superposed, very distinct
layers of a granular, probably coagulated sub-
stanoe ; — forming a kind of staff or baton by which
the eggs are bound together in groups ; for, accord-
ing to Kolliker (loc. cit. p. 14), it ( Tremoctopus )
carries the entire mass attached to the suckers of
one of its arms.

15 See Quoy and Gaimard , Ann. d. Sc. Nat.
XX. 1830, p. 472, PI. XIV. B., and Ferussac,
loc. cit. Octopus , PI. XXVIII. fig. 3.

1 For the male genital organs of Octopus , see
Cuvier , M£m. loc. cit. p. 32, PI. IV. fig. 5 ; he
regards the upper glandular portion of the deferent
canal as a Fesicula seminalis, and the coecum
appended to it as a Prostata. See, also, Delle
Chiaje , Descriz. Tav. VI. fig. 2, Tav. XI. fig. 2, 3,
Tav. XII. fig. 28 (Octopus, Sepia and Loligo );
Wagner , Icon. zoot. Tab. XXIX. fig. 22 ( Octopus ) ;
Peters, in Muller's Arch. 1842, p. 332, Taf. XVI.
fig. 2, 3 (Sepiola), and especially the beautiful
figure of those of Sepia by Milne Edwards , in
the Ann. d. Sc. Nat. XVILL 1842, p. 344, PI. XV.

§ 259.

THE CEPHALOPODA.

297

which it is seen of a milk-white color. Its posterior extremity is attached,
by a short, small ligament, to a kind of piston which forms the anterior por-
tion of the projectile apparatus.

This piston is a solid, cylindrical body, continuous behind with a spiral
ligament which is contained in a thin sheath extending to the posterior
extremity of the tube, in a fold of which it terminates. <2)

The Spermatophores are evidently formed in the upper glandular portion of
the deferent canal, where droplets of sperm are often seen arranged in rows,
and, at first, appear surrounded by simple, colorless envelopes ; these, as
they advance in the Vas deferens , gradually resemble more and more the
perfect Spermatophores.

Those found in the Bursa Needhamii are always regularly arranged, and
sometimes form, lengthwise, several superposed layers. Their anterior
extremities always point forwards, and not unfrequently their posterior
ends are bound together by long, flattened, interlaced filaments. These
Spermatophores are in the highest degree hygroscopic : they absorb liquids
very quickly, and then their posterior extremity bursts, allowing the escape
of the compressed spiral ligament together with its sheath, and the piston,
which draws with it the sperm-sac tcrwhich it is attached.®

The projection of the seminal sacs occurs, most probably, at the moment
when, during coition, the Spermatophores pass from the penis of the male
into the sac of the mouth of the female. A true intromission of the penis
into the female genital opening, appears impossible with these animals, so
that coition consists only in a simple juxtaposition of the genital organs.®
The fecundation of the eggs should occur very early — while the eggs are

2 Needham (An account of some new Microscop-
ical Discoveries, London, 1745, or Nouv. d^couv.
faites avec le Microsc. Leyde, 1747, PI. III. IV.),
was the first who described accurately the Sper-
matophores of Loligo vulgaris. With those of
the Loligina, the posterior extremity is enlarged,
with one or two constrictions, and contains the
spiral ligament with its sheath ; the piston also,
from its deep-brown color, is easily seen; see Krohn ,
in Froriep's neue Notiz. XII. 1839, p. 17, fig. 20
(Sepia)} Milne Edwards , Ann. d. Sc. Nat. XVIII.
1842, p. 335, PI. XII. fig. 1-5, XIII. fig. 1-6
(Loligo and Sepia)} Peters , in Muller's Arch.
1842, p. 334, Taf. XVI. fig. 11 (Sepiola). With
those of Octopus , and Eledone , the posterior en-
largement is very slight, and often, at this point,
the envelope is entirely involuted ; the seminal sac,
moreover, is remarkable from its spiral form ; see
Milne Edwards , loc. cit. p. 338, PI. XIII. fig.
8-10, XIV. fig. 1-6 (Octopus and Eledone );
Philippi , in Muller's Arch. 1839, p. 301, Taf. XV.
fig. 1-6 (Eledone)} this last author has erroneously
taken the spiral turns of the ligament for hooks
pointing backwards.

0 Redi (De Animalculis vivis quae in corporibus
animalium vivorum reperiuntur, Lugd. Batav. 1729,
p. 252, Tab. II. fig. 2), was the first who saw
these Spermatophores ; but he took them for worms.
S wammerdamm, on the other hand (Bib. d. Natur,
p. 353, Taf. LII. fig. 6, 7), and especially Needham
(loc. cit.), had a correct idea of their nature, for
they regarded the white substance they contained
as sperm, and the Spermatophores themselves as a
kind of cases or machines. But this did not pre
vent the later anatomists from regarding them as
parasites. Thus Delle Chiaje described those of
Octopus and Sepia under the names of Monosto-
mum octopodis , and Scolex dibothrius (Mem. IV.
p. 53, Tav. LV. fig. 8, 14, 9, 9.d). Even latterly, this
naturalist has not relinquished this opinion, for he

has figured anew, as an Entozoa, and even as an
Echinorhynchus , the uncoiled Spermatophores of
Loligo (Descriz. III. 1841, p. 138, Tav. XI. fig.
12, 13). Wagner , also, formerly regarded those
of Sepia as containing an Echinorhynchus , and
has figured as such the piston with the spiral liga-
ment in a rudimentary state (Lehrb. d. vergleich.
Anat. 1835, p. 312, and Muller's Arch. 1836, p.
230, Taf. IX. fig. B. C.).

Carus went even still further, and described the
Spermatophores as gigantic spermatic animals un-
der the name of Needhamia expulsoria ; and re-
garded the parts they contained, such as the
sperm-sac, the piston, the spiral ligament, &c., as
a colon, a small intestine, a stomach, a crop, and
an oesophagus (Nov. Act. Acad. Nat. Cur. XIX. I.
1839, p. 3, Tab. I., and Erlauterungstaf. loc. cit.
Hft. V. 1840, p. 4, Taf. I. fig. 10). It was not until
1839, a time when several naturalists were con-
vinced of the presence of spermatic particles in the
sperm-sac, that the true nature of these bodies was
fully understood ; see Philippi , in Muller's Arch.
1839, p. 301; Krohn , in Froriep's neue Notiz.
XII. 1839, p. 17 ; Siebold, Beitrilge z. Natur-
gesohichte d. wirbell. Thiere, 1839, p. 51; Peters , in
Muller's Arch. 1840, p. 98, and Milne Edwards,
Ann. d. Sc. Nat. XIII. 1840, p. 193. Leuckart
(Zool. Bruchstiicke, lift. II. 1841, p. 93) has given
the history and criticism of the opinions relating to
the sperm machines of Needham.

4 Aristotle (Hist. Animal, lib. V. cap. 5) had
already declared that the Cephalopoda copulate by
a kind of embrace. From the observations of Le -
bert and Robin (loc. cit. p. 135, and Ann. d. Sc.
Nat. IV. 1845, p. 95, PI. IX. fig. 5, 6), it would
appear that the males do not deposit the spermatic
particles further in than the cavity of the mantle
of the females ; for they observed, with a female
Loligo , numerous Spermatophores glued to the
internal surface of this cavity, near the oviduct.

298

THE CEPHALOPODA.

§§ 260, 261.

still at the bottom of the female genital organs ; for, later, the action of the
sperm would be obstructed by their solid envelopes. It must, therefore, be
supposed that the sperm is carried from the cavity of the mantle into the
ovarian capsule, either by means of the anti-peristaltic movements of the
oviduct, or by the aid of the aquiferous system.®

§ 260.

With the individuals hitherto known as the Hectocotyli, the genital organs
occupy a space disproportionably large to the size of the body. The round,
smooth enlargement on their posterior extremity is a genital capsule, with
thin walls, and containing the sperm and the copul atory organs. (1) The
sperm forms a long, moniliform, clustered string, composed of thick oval
bundles of spermatic particles, regularly bound together by fasciculi of
hair-like spermatic particles.® In this clustered string are included, also,
the Ductus ejaculatorius and the very long and retractile penis. With
Tremoctopus violaceus, this penis sometimes projects between the fifth of
the posterior pair of suckers, as a small cylindrical, folded prolongation.®

§261.

The Development of the Cephalopoda is almost without analogy, and,
from the remotest times, has excited the curiosity of Naturalists; but it is
only very recently that it has been correctly understood and followed from
its first stages. (1)

After the disappearance of the germinative vesicle, the vitellus divides ;
but this segmentation is only partial. Usually, at the acute extremity of the
vitellus, where the germinative vesicle is found, there appears a small
elevation from the vitelline mass, divided into halves by a furrow. Each

5 According to Kolliker (Entwickel. &c. p. 11),
the eggs are fecundated while yet contained in the
ovarian capsule.

1 See Hectocotylus octopodis , in Ann. d. Sc.
Nat. loc. cit. fig. 1-3, b.

1 have so observed it with the males of Tremoc-
topus violaceus ; and Dujardin , also (Hist. Nat.
d. Helminth, p. 482), has observed a smooth cord
composed of capillary spermatic particles with
Hectocotylus octopodis , Cuv.

I am uncertain as to the origin of this cord, but,
in the specimens preserved in alcohol, which I have
examined, it appeared probable that it was prima-
rily contained in the deferent or in the testicular
canal.

3 The Ductus ejaculatorius of Tremoctopus
violaceus , which is gradually continuous into the
penis, begins by a well-marked, clavate thickening,
projecting into the genital capsule, and apparently
perforated at its upper extremity, at which point,
perhaps, the sperm enters. Near the end of the
penis, this canal has, over a considerable extent,
small horny tubercles, and it is probable that this
portion can be everted, thus allowing the possi-
bility of an intimate union with the female organs.
I am unable to say whether this is so with the other
Hectocotyli. The penis of Hectocotylus argo-
nautae, according to a figure of Delle Chiaje (loc.
cit. Tav. XVI. fig. 1, a), and Costa (loc. cit. PI.
XIII. fig. 2s c), projects from the posterior ex-
tremity of the body ; but it may be, that with the
specimens examined by these naturalists, this organ

had become free from an accidental rent of the
genital capsule.

1 Aristotle (Hist. Animal, lib. V. cap. 16, 4),
and in the last century, Cavolini (Abhandl. fiber
die Erzeugungder Fisclie u. d. Krebse, 1792, p. 54)
had already declared that, with Sepia, the vitelline
sac is situated on the head of the embryo, and, as
it were, hanging from the mouth ; but it is only
latterly that this statement has been thoroughly
verified •, see Froriep , Has Thierreich, Abth. Y.
1806, p. 28, fig. 8-10 Cams , Erlauterungstaf. lift.
III. 1831, p. 10, Taf. II. fig. 16-30*, Cuvier , Sur
les oeufs de Seiche, in the Nouv. Ann. du Mus. 1.
1832. p. 153, PI. VIII. fig. 6-14, also in abstract
in Ann. d. Sc. Nat. XXVI. 1832, p. 69, or Froriep"1 s
Notiz. XXXIV. p. 199 ; Coldstream, On the foetus
of Sepia officinalis, in the Lond. and Edinb. philos.
Magaz. Oct. 1833, or Froriep's Notiz. XXXIX. p.
6 •, Dus; is, Note sur le developpement de l’embryon
chez les Mollusques cephalopodes, in Ann. d. Sc.
Nat. VIII. 1837, p. 107, PI. V., or Froriep's neue
Notiz. VII. p. 209, fig. 3-9.-, D'Orbigny , in Ferus-
sac, loc. cit. Loligo, PI. X. fig. 3-6 •, Fan Beneden,
Recherches sur l’cmbryog^nie des Sepioles, in the
Nouv. M£m. de l’Acad. de Bruxelles, XIV. 1841,
PI. I.-, Delle Chiaje, Descriz. I. p. 38, Tav. VI.
fig. 6, 7 {Sepia), Tav. XIV. fig. 14-24 {Argonau-
ta ), and Tav. XXIX. fig. 2-5 (Sepiola). But the
first phases of their development remained unob-
served, until Kolliker, in 1844, filled this deficiency
by his masterly work — Entwickelungsgeschich-
te der Cephalopoden.

$ 261.

THE CEPHALOPODA.

299

of these halves is also divided, and so on, forming four, eight, &c., segments,
each resembling a more and more acute triangle, with a converging apex,
while its base is directly continuous with the remaining vitellus. After a
certain number of segments have been formed by these longitudinal divisions,
transverse furrows are seen separating the apices of the segments, and
forming, at first, in the centre of the eminence^ a ring composed of eight to
sixteen portions ; but finally, from a further segmentation in both direc-
tions, these furrows become a mass of increasingly smaller and more
numerous parts.®

This portion of the vitellus, which, during this time, has also been devel-
oped at its periphery, is changed into a blastoderma composed of two layers.
Upon this blastodermal membrane several folds appear, which are the first
traces of the future embryo, viz: first, a median, uneven fold or rudiment
of the mantle, and then two others, lateral, which ultimately form the eyes.
Between these three folds are placed two others which become the two lat-
eral halves of the funnel. Subsequently, the folds of the branchiae and arms
appear ; and among these last the two belonging to the ventral surface are
first seen. Still later, the folds of the eyes and arms, and their surrounding
parts, become more and more prominent upon the vitelline mass, thus
forming the cephalic portion of the embryo. From this last, opposite the
vitellus, the fold of the mantle is sketched as the future posterior portion of
the body. The general form of the animal may, therefore, be recognized
very early, although the cephalic portion quite exceeds that of the mantle.

At the posterior or dorsal surface of the cephalic portion, the mouth
appears, first as a semilunar depression, and the internal layer of the blas-
toderma gradually extends from the border of this portion over the whole
vitelline mass, producing, finally, a true vitelline sac. The external surface
of this is covered with ciliated epithelium which gradually spreads over the
other parts of the embryo, such as the lobes of the head, the arms, the eyes,
and the mantle, while that of the branchiae, and the funnel, the halves of
which have then united, is never ciliated.®

Of the Cartilages, the articular and cephalic are the first developed. The
internal shell,® the nervous system, the heart with the vascular and respi-
ratory systems, the digestive canal and its appendages, and the ink-sac, are
formed successively, and may be easily seen at the termination of the
embryonic life, when, also, are found some chromatic cells.

As to the vitelline sac, it should be remarked that it never communicates
with the intestinal canal, as has hitherto been supposed.® The cephalic
portion, which always extends upon this sac, embraces a part of it, so that
it is divided by a constriction into an internal and external portion, the
former of which extends even into the cavity of the mantle. The con-
stricted portion is gradually elongated, and finally becomes a long, very
narrow canal, extending from the cephalic extremity to the side of the

2 See Kolliker , loc. cit. p. 17, Taf. I. p. 379, and Maravigno , Ann. d. Sc. Nat. VII.

3 With Loligo , the vitelline sac and its ciliated 1837, p. 174.

epithelium are formed quite early ; while with Se- 5 Most of the earlier anatomists were led into
pia, they do not appear until the embryo and its error from the tenuity of the canal of communica-
different organs have become quite large. With tion, and the difficulty of its examination. They
the first, the embryos have rotatory movements, but supposed that the external vitelline sac communi-
with the second this is not the case ( Kolliker , loc. cated with the oesophagus and stomach, by this
cit. p. 54). canal ; see Cams , loc. cit. Taf. II. fig. 27 ( Loli -

4 With Argonauta , the external shell is formed go) ; Cuvier , loc. cit. PI. VIII. fig. 9 ; Duges, loc.
while the embryo after its escape from the egg, is cit. PI. V. fig. 3 (Sepia) and Van Beneden , loc. cit.
still persistent in the spawn inside the shell of its PI. I. fig. 13 (Sepiola). Kolliker was the first to
parent ; see Power , in fViegmann's Arch. 1845, 1. view it correctly (loc. cit. p. 86, Taf. IV.).

300

THE CEPHALOPODA. § 261.

mouth, and producing a communication between the internal and external

sacs.

The vitellus of the internal sac gradually disappears, and is replaced
through this canal of communication by that of the external sac. During
the successive development of the organs contained in the cavity of the
mantle, the internal vitelline sac is divided into lobes which are finally broken
up and absorbed ; while the intestinal canal, the remaining organ of the
embryo, is developed, quite independently, from the vitelline mass.

As to the development of the males ( Hectocotyli ) of Argonauta and
Tremoctopus, nothing is yet known except of its last period. It has been
observed, however, that, during the time they are in the egg, they have their
proper form which is so remarkably different from that of the females.®

6 Had the fact that the Hectocotyli exist in the
egg with their proper form, among the eggs of fe-
males of certain species, been properly observed,
the true relations of these supposed parasites to the
animals in which they live, would have been known
long ago. A passage of Maravigno , first properly
interpreted by Kolliker (Ann. of Nat. Hist.loc.cit.
p. 414) shows clearly that this Italian naturalist, in
his researches connected with Argonauta , was in
error only as to the eggs which contained the male
individuals.

* [ § 201, note 6.] The subject of the Hectocoty-
lus to which such frequent mention has been made
in these pages, is one that has elicited a good deal
of attention of late years, but, now, happily, seems
pretty definitely settled. Chief among these inves-
tigators are H. Muller , and Virany and Vogt.
They have pretty clearly shown the non-independ-
ent character of these forms. The details of these
researches cannot here be given ; it may be re-
marked, however, that these observers have all
studied these forms upon living specimens on the
coast. It has been shown that the Argonautae on
which these Hectocotyli are found, have a highly-
developed testicle, the situation and structure of
which correspond to those of the common Cephalo-
poda, and which communicates with the Hectoco-
tylus.

In conclusion, I may quote H. Muller’s own
words : “ It is then proved that the Hectocotylus
is formed on a male Argonauta , and is nothing but
an arm metamorphosed in a very irregular man-
ner. This arm, or the Hectocotylus, is detached

He says thus : “ Mais encore que le petit poulpe,
au sortir de l’oeuf, ne ressemble pas enticement a
ce qu’il sera par la suite ; c’est alors une sorte de
petit ver (vermicello) pourvu de deux rang£es de
ventouses dans la longueur, avec un appendice fili-
forme d une extrdmitd, et un petit renflement vers
l’autre, oii il paralt que sont les organes de la di-
gestion.”— (Ann. d. Sc. Nat. VII. 1837, p. 173.)
The mode of development of these males differs
undoubtedly very much from that of the females.*

when it has been, filled with the sperm which is
formed in a true testicle of the Argonauta itself, and
it then plays an apparently independent life. In this
condition, it meets the female Argonautae which,
by a true copulation, it impregnates, as I have
observed with the Hectocotylus of a Tremoctopus ,
and it resembles in this, as also by its movements,
by a kind of circulation, and by the long duration
of its life after detachment, a true male animal.”
For the literature of this subject, see, beside the
writings referred to in the above pages, Kolliker ,
Transact. Linn. Soc. London, XX. 1846, p. 9, PI.
I. j Bericht yonder zootomischen Anstaltzu Wiirtz-
burg, Leipzig, 1849, p. 67, Taf. I. II ; Power
( Madame ) Mollusques Mediterrandens, Ire partie
Gdnes, 1847-51, p. 34, 126, PI. XLI. ; Virany and
Vogt , Ann. d. Sc. Nat. XVII. 1852, p. 146, PI. VI.
-IX. ; H. Muller , Ann. d. Sc. Nat. 1852, XVI. p.
132 ; also, in extenso , in Siebold and Kblliker’s
Zeitsch. IV. p. 1, Taf. I. and p. 346 ; and Siebold ,
in Ibid. IV. p. 122. — Ed.

INTRODUCTORY NOTE TO THE CRUSTACEA.

Witiiin a short time, the class Crustacea has received a contribution of
so valuable a character that I cannot omit to mention it specially in a note.
I refer to the large and comprehensive work of Dana, published this year
(T853). This work, aside from its high zoological value, includes anatomi-
cal details and the discussion of principles in animal morphology, of great
importance to the student of this interesting yet difficult class of animals.

It will be found that constant reference has been made to the anatomi-
cal details, in my notes; but the doctrines advanced as to the morphological
structure of these animals, more than equally important, could be here
given only in a separate form. I have been the more induced to include
them here, from the fact that the work in question will have a very
limited circulation, comparatively, and can be accessible only to a few.
With these views, I have solicited Professor Dana to put his particular
principles into a condensed form for this work, and he has kindly favored
me with the following account :

The several types of structure among Crustacea are distinguished, pri-
marily, by the different degrees of centralization or cephalization in the
species, which degrees of cephalization are exhibited in the form of the
body, and position, number, form or length of the appendages. The
higher cephalization is seen in the larger number of organs that are
pressed into the service of the senses and mouth ; in the closely-crowded
position and small size of these organs; in the little elongation of the
antennae ; and in the obsolescence of the abdomen and absence of abdominal
appendages. Thus, in the Brachyura, nine segments and their pairs of
appendages, out of the fourteen cephalothoracic, belong to the senses and
mouth ; they are all small, and gathered into a short space ; the antennae
are exceedingly small, excepting the basal joint which is the seat of
sense ; the abdomen in the males is small and without appendages. In the
Maioids, the highest Brachyura, the head is very narrow, with the anterior
antennae longitudinal, and the base of the outer antennae soldered without
suture to the shell. The concentration is here most complete. The wid-
ening of the front in the Cancroids shows a relaxation of the concentration,
26

INTRODUCTORY NOTE TO THE CRUSTACEA.

302

as do also other characteristics ; the loosening of the outer maxillipeds in
the true Cancers, and most swimming Crustacea and Corystoids,iis another
step in this relaxation ; the elongation of the antennae in the Corystoids
and Anomoura is another step ; the loosening of the abdomen from the
ventral surface of the cephalothorax ; its becoming loosely indexed or
even extended ; its taking appendages — are among the other steps seen in
the Anomoura ; the outer maxillipeds becoming pediform, and then the
next pair pediform also, showing a tendency to a passage from the mouth-
series to the foot-series, are other steps downward, observed in the Macrura ;
and the elongated abdomen with its regular series of organs as well as the
elongated antennae, the union without fossettes, and eyes without sockets,
all exhibit the relaxation of centralization that marks the Macrura.

A further degradation is seen in the obsolescence of some of the pairs-of
feet and abdominal appendages, as in the Mysis group ; and the same
principle is exemplified in the Brachyura, where the posterior cephalo-
thoracic legs become small or rudimentary, or swimming legs.

There are, hence, two methods by which the passage of Crustacea from
the higher to the lower grades takes place :

1. A diminution of the centralization leading to an enlargement of the
circumference or sphere of growth at the expense of concentration, as in the
elongation of the antennae, a transfer of the maxillipeds to the foot-series,
and the elongation of the abdomen and abdominal appendages.

2. A diminution of force as compared with the size of the structure,
leading to an abbreviation or obsolescence of some of the circumferential
organs, as the posterior or cephalothoracic legs, or anterior antennae, or
the abdominal appendages (if such appendages belong to the type embrac-
ing the species).

The Macrura, Anomoura, and Brachyura are alike in having normally
nine cephalic annuli (out of the fourteen cephalothoracic), and but five
foot-annuli. The Mysis and Squilla groups are in the same category.
There are species that show a tendency to a transfer of the posterior
mouth-annuli or appendages to the foot-series, but it is only a tendency.
These together constitute the First type among Crustacea.

In the Second type, there are seven cephalic annuli and pairs of append-
ages, and seven foot-annuli or pairs of feet ; such are the Isopoda, Aniso-
poda and Amphipoda.

In the Third type, there are normally six (or five) cephalic annuli, out
of the whole normal number, fourteen, — the eight (or nine) posterior annuli
belonging to the foot-series, part of which (the three posterior pairs and
often more) are usually obsolete. Moreover, the abdomen, by the second
law of degradation, mentioned above, is without appendages — such are
the Entoinostraca.

*

INTRODUCTORY NOTE TO THE CRUSTACEA.

303

In the Fourth type , there are six (or five) cephalothoracic annuli, as in the
Entomostraea, with which group they might be associated. But other
peculiarities lead to a separation, and the species referred to are the
Cirripedia.

In the Fifth type , there are five (or four) cephalothoracic annuli, out of
the whole normal number fourteen ; in other words, the mouth never
includes more than a single pair of maxillae with the mandibles. More-
over, by the second law of degradation, all the jointed cephalothoracic
appendages are wanting. These are the Rotatoria.

The following table presents a view of the number of cephalic annuli in
these Types, and also the mean size :

Typical No. of
annuli.

Type I. Decapoda or Podophthalmia. — Sub-type I. Brachyura, l
Sub-type II. Macrura, >

Type II. Tetradecapoda,

Type III. Entomostraea,

Type IV. Cirripedia,

Type V. Rotatoria,

9

7

6-5

6-5

5-4

cephalic Mean normal
length in lines.

24 (and breadth 24).
36 (and breadth 6).

6

1

1

1-9

See pp. 1406 and 1407 (loc. cit.), for observations on mean size in
the Entomostraea and Cirripedia, where an important principle is brought
out, and where, also, some explanations are furnished which make the state-
ment given above of the mean size, intelligible. — Ed.

BOOK TWELFTH.

CRUSTACEA.

CLASSIFICATION.

§ 262.

In the Classification of the Crustacea, the remark of Erickson a) should
be adduced, that, with these animals, the external locomotive organs are not
limited, as with the other Arthropoda, to the anterior part of the body,
but may exist on all its segments, and often with a shape so changed, that
they become foot-jaws, or anal-feet, or oars. If the Crustacea are ex-
amined from this point of view, it will not appear surprising that the
Myriapoda are classed among them ; for they do not properly belong
either to the Arachnoidae or to the Insecta.

ORDER I. CIRRIPEDIA.

Family : Balanodea.

Genera : Balanus, Chthamalus, Coronula, Tubicinella.
Family : Lepadea.

Genera : Otion, Cineras , Lepas, Pollicipes.

ORDER II. SIPIIO NO STOMA.

Family : Penellina.

Genera : Penella, Peniculus, Lernaeocera, Lernaea.

Family : Lernaeodea.

Genera : Achtheres , Tracheliastes, Brachiella, Lernaeopoda, Anchor ella ,

Chondr acanthus.

Family : Ergasilina.

Genera : Dickelestium, Lamproglena , Ergasilus, Nicothoi.

Erickson, Entomographien, lift. 1. p. 12.

<$ 262.

THE CRUSTACEA.

305

Family : Caligina.

Genera: Caligus, Pandarus, Trebius, Dinematura, Euryphorus, Phyllo-

phora.

Family : Akoulina.

Genus : Argulus.

ORDER III. LOPHYROPODA.

Genera: Cyclopsina, Cyclops , Anomalocera, Calanus, Peltidium, Hersilia,
Polyphemus, Daphnia, Evadne, Lynceus, Cypris.

ORDER IV. PHYLLOPODA.

Genera: Lymnadia, Isaura ( Estheria ), Apus, Branchipus, Artemia,

Ckirocephalus.

ORDER V. POECILOPODA.

Genus : Limulus.

ORDER VI. LAEMODIPODA.

Genera : Cyamus, Caprella, Leptomera , Aegina.

ORDER VII. ISOPOD A.

Family : Bopyrina.

Genera : Bopyrus, Phryxus, Jone, Cepon.

Family : Cymotuoidea.

Genera : Cymothoa, Aega, Nerocila, Anilocra , Serolis.

Family : Spiiaeromatoda.

Genera : Sphaeroma, Cymodocea, Nesea, Amphoro'idea.

Family : Idotoeoidea.

Genus : Idothea.

Family : Asellina.

Genera : Dygia, Janira , Asellus, Lygidium, Porcellio, Oniscus, Armadil-

lidium, Tylos.

ORDER VIII. AMPHIPODA.

Genera: Vibilia, Ilyperia ( Hiella ), Phronima, Ipkimedia, Ampkithoe,
Talitrus, Gammarus.

26*

306

THE CRUSTACEA.

§ 262.

ORDER IX. STOMAPODA.

Genera : Phyllosoma, Amphion, Mysis, Leucifer, Cynthia, Thysanopoda,
Alima, Squilla, Sqnillerichthus .

ORDER X. DEC APOD A.

SUB-ORDER I. MACRURA.

Genera: Penaeus, Pasiphaea, Alpheus, Caridina, Hippolyte, Palaemon,
Arist.eus, Gebia, Cattianassa, Crangon, Nephrops, Astacus, Homarus
Palinurus, Scyllarus, Galathea.

SUB-ORDER II. ANOMURA.

Genera : Pagurus, Porcettana, Remipes, Ranina, Homola, Lithodes,
Dromia, Dorippe.

SUB-ORDER III. BRACHYURA.

Genera : Lupea, Portunus, Eriphia , Carpilius, Cancer, Maia, Leucippa,
Hyas, Pisa, Stenorhynchus , Mithrax, Camposcia, Ilia, Grapsus, Ocy-
poda, Uca, Gecarcinus, Thelphusa.

ORDER XL MYRIAPODA.

SUB-ORDER I. CIIILOGNATHA.

Genera : Glomeris, Blaniulus, Platyulus, Polydesmus, Spirololus, Julus.
SUB-ORDER II. CHILOPODA.

Genera : Cryptops, Geophilus, Scolopendra, Litholius, Scutigera.

BIBLIOGRAPHY.

Sicammerdamm. Yon der Zergliederung einer Ivrebsschncckc, in the
Bibel der Natur, 1752, p. 84.

Schaffer. Der fischformige Kiefenfuss, 1754. Die geschwanzten und
ungeschwanzten zackigen Wasserfldhe, 1755. Der krebsartige Kiefenfuss,
1756.

Rosel. Der Flusskrebs; in his Insekten — Belustigungen, Tk. III. 1755,
p. 307.

O. F. Muller. Entomostraca, 1785.

Cavolini. Abhandlung fiber die Erzeugung der Fische und der Krebse,
1792.

Ramdohr. Beitrage zur Naturgeschichte einiger deutschen Monokulus-
Arten ; in his Micrograpkischen Beitragen zur Entomologie und Helminth-
ologie, 1805.

Jurine. Memoire sur J’Argule foliace ; in the Ann. du Mus. d’Hist.
Nat. VII. 1806, p. 431. Histoire des Monocles, 1820.

§ 262.

THE CRUSTACEA.

307

Prevost. Memoire sur le Chirocephale ; an appendix to Jurines His-
toire des Monocles, p. 201.

Cuvier. Memoire sur les animaux des Anatifes et des Balanes ; in the
Mem. du Mus. d’Hist. Nat. II. 1815, p. 85, also in his Memoires sur
les Mollusques, loc. cit.

Treviranus. Abhandlungen iiber den inneren Bau der ungefliigelten
Insekten ; in his Vermischten Schriften anatomischen und physiologischen
Inhalts. Bd. I. II. 1816-17.

Geveke. Be Cancri Astaci quibusdam partibus. 1817.

Suckow. Anatomisch-physiologische Untersuchungen der Insekten und
Krustenthiere. 1818.

Straus. Memoire sur les Baphnia ; in the Mem. du Mus. d’Hist.
Nat. V. 1819, p. 380. Memoire sur le Cypris, Ibid. VII. 1821, p. 33.
Memoire sur les Hiella, nouveau genre de Crustaces Amphipodes, Ibid.
XVIII. 1829, p. 51. IJeber Estheria dahalacensis, eine neue Gattungaus
der Familie der Baphniden ; in the Museum Senckenbergianum. Bd. II.
* 1837, p. 117.

Brongniart. Memoire sur le Limnadia ; in the Mem. du Mus. d’Hist.
Nat. VI. 1820, p. 83.

Saoigny. Bescription de l’Egypte, Hist. Nat. Crustaces. 1820-30.
Rathke. Anatomie der Idothea Entomon ; in the Neuesten Schriften
der naturforschenden Gesellschaft in Banzig. Bd. I. 1820, p. 109. Zur
Fauna der Krym. 1836. Be Bopyro ct Nereide, cominentationes anatom-
ico-physiologicae duae, 1837. Bemerkungen iiber den Bau des Bicheles-
thimp Sturionis und der Lernaeopoda stella.ta ; in the Nov. Act. Nat.
Cur. XIX. 1839, p. 127. Beitriige zur Fauna Norwegens, Ibid. XX.
1843, p. 3.

Leon Dufour. Recherches anatomiques sur le Lithobius forficatus et la
Scutigera lineata; in the Ann. d. Sc. Nat. II. 1824, p. 81.

Desmarest. Considerations generates sur la Classe des Crustaces, 1825.
J. Midler. Zur Anatomie der Scolopendra morsitans; in the Isis,
1829, p. 549.

John Thompson. Zoological Researches and Illustrations, or Natural
History of nondescript or imperfectly known animals. I. Pt. 1, 1831—34.

Nordmann. Mikrographische Beitriige zur Naturgeschichte der wir-
bellosen Thiere, Hft. II. 1832.

Zenker. Be Gammari Pulicis historia naturali atque sanguinis circuitu
commcntatio, 1832.

Kutorga. Scolopendrae morsitantis anatome, 1834.

Roussel de Vauzeme. Sur le Cyamus Ceti, in the Ann. d. Sc. Nat. I.

1834, p. 239.

Burmeister. Beitriige zur Naturgeschichte du Rankenfiisser, 1834.
Beschreibung einiger neuen oder weniger bekannten Schmarotzerkrebse ; in
the Nov. Act. Nat. Cur. XIX. 1835, p. 271.

Martin St. Ange. Memoire sur l’organisation des Cirripedes, 1835,
also, in the Mem. presentes a l’Acad. Roy. d. Sc. de l’lnst. de France, VI.

1835, p. 513.

Kollar. Beitrage zur Kenntniss der lernaenartigen Crustaceen ; in the
Ann. des Wiener Mus. d. Naturgeschichte, Bd. I. 1835, p. 79.

Milne Edwards. Ilistoire nat.urelle des Crustaces, 1834-40; also,
article Crustacea, in Cyclop, of Anat. I. p. 750.

308

THE CRUSTACEA.

§ 262.

John Coldstream. Cirrkopoda, in the Cyclop, of A.nat. I. p. 683.

Kroyer. Ueber die Schmarotzerkrebse, in bis Naturhistorisk Tids-
krift. Bd. I. II. 1836-37, also in the Isis, 1840, p. 702, 1841, p. 187.
Ueber den Bopyrus abdominalis, Ibid. III. or in Isis, 1841, p. 693, or in
Ann. d. Sc. Nat. XVII. 1842, p. 142. Monografisk Fremstilling af
Slaegten Hyppolytes Nordiske Arter. 1842.

Brandt. Beitrage zur Kenntniss des inneren Baues von Glomeris mar-
ginata ; in Muller’s Archiv., 1837, p. 320. Becueil de Memoires relatifs
a l’ordre des Insectes Myriapodes, 1841 ; Extracted from the Bull,
scientifique publ. par. l’Acad. Impel', d. Sc. de St. Petersburg, Y. — IX.

Van der Hoeven. Becherches sur l’bistoire naturelle et l’anatomie des
Limules, 1838.

Loven. Evadne Nordmanni, ein bisher unbekanntes Entomostracon ; in
Wiegmann's Arch. 1838, Bd. I. p. 143.

Joly. Histoire d’un petit Crustace (Artemia salina); in the Ann. d. Sc.
Nat. XIII. 1840, p. 225. Becherches zoologiques, anatomiques et physio-
logiques sur l’Isaura cyeladoides, Ibid. XVII. 1842, p. 293.

Zaddach. De Apodis cancriformis anatome et historia evolutionis, 1841.

Nmvport. On the organs of reproduction and the development of Myria-
poda ; in the Philosoph. Transact. 1842, Pt. II. p. 99, also in Froriep's
neuen Notiz. XXI. p. 161. On the Structure and Development of the ner-
vous and circulatory systems, and on the existence of a complete circulation
of the blood in vessels in the Myriapoda and the Macrourous Arachnida,
Ibid. 1843, Pt. I. p. 243; also in Froriep's neuen Notiz. XXVIII. p. 177,
or in Ann. d. Sc. Nat. I. 1844, p. 58, or in Ann. of Nat. Hist. XII.
p. 223.

Rymer Jones. Myriapoda , in Cyclop, of Anat. III. 1842, p. 544.

Lereboullet. Memoire sur la Ligidie ; in the Ann. d. Sc. Nat. XX.
1843, p. 103.

Vogt. Beitrage zur Naturgeschichte der schweizerischen Crustaceen
(Argulus und Cyclopsina), in the Nouv. Mem. de la Soc. helvetique, VII.
1843.

Frey. De Mysidis flexuosae anatome commentatio, 1846.

ADDITIONAL BIBLIOGRAPHY.

J. D. Dana and E. C. Herrick. Description of the Argulus Catostomi.
Amer. Jour, of Sc. XXXI. p. 297.

J. D. Dana and C. Pickering. Description of the Caligus Americanus.
Ibid. XXXIV. p. 235.

J. D. Dana. On the Eyes of Sapphirina, Corycaeus, &c. Proceed.
Acad. Nat. Sc. Philad. 1845, II. p. 185, and Amer. Jour, of Sc. 2nd Ser.
IX. p. 133.

Beport on the Crustacea of the U. S. Exploring Expedition, &c.

&c., part I. 1852, 4to. pp. 688, part II. 1853, pp. 689-1618. With a folio
Atlas of 96 Plates.

Leydig. Ueber Argulus foliaceus ; ein Beitrag zur Anatomie, His-
tologie und Entwickelungsgeschichte dieses Thieres; in Siebold and Kolli-
ker's Zeitsch. II. 1850, p. 323.

'Ueber Artemia salina und Branchipus stagnalia ; Beitrag zur

anatomischen Kenntniss dieser Thiere, in Ibid. III. 1851, p. 280.

Baird. The Natural History of the British Entomostraea. Published

$$ 263, 264.

THE CRUSTACEA.

309

by Ray Soc. London, 1850. In this work are embodied the results of his
earlier researches published in the Trans, of the Berwick Nat. Club, &c.

** Darwin. A monograph of the sub-class Cirripedia with figures of all
the species. Published by Ray Soc. London, 1851. This work is rich in
anatomical details, many of which are new.

Van Benedcn. Recherches sur quelques Crustaces inferieurs, in the
Ann. d. Sc. Nat. XYI. p. 71. — Ed.

CHAPTER I.

EXTERNAL ENVELOPE AND CDTANEODS SKELETON.

§ 263.

The External envelope of the Crustacea is more or less solid, and has the
form of a multi-articulated, cutaneous skeleton, sometimes of a leathery or
horny consistence, but generally consists of a hard, calcareous shell.

It has, consequently, no contractility, and participates in the movements
of the body only in a passive manner, that is, by the interarticular soft
skin, and by the antennal and foot-like processes.

In this cutaneous skeleton, whether it is leathery, horny, or calcareous,
there is a peculiar organic substance as its base. This substance, which
is found in the cutaneous skeleton of other Arthropoda also, has received
the name of Chitine. It resembles cellulose of plants in its insolubility in
caustic potass, but differs essentially from it in containing nitrogen. (1)

§ 264.

Nothing in general can be said as to the Histological composition of this
cutaneous skeleton of the Crustacea, for it differs widely not only in the
various orders and families, but even in the different parts of the body of
the same species. (1) Whether hard or soft, it is usually composed of

1 This Chitine which was formerly taken for a
horny substance, was first discovered with the
Insecta by Odier (Mem. d. 1. Soc. d’Hist. Nat. de
Ihtris, I. 1823, p. 29). Latterly, it has been care-
fully investigated by C. Schmidt (Zur vergleich.
L’hysiol. d. wirbellos. Thiere, 1845, p. 32), who
found, moreover, that the cutaneous skeleton of
Crustacea has the same composition as that of
Jnsecta.

* [ § 264, note 1.] Of the results of Lavalle's
Observations it may be well to add his concluding
remarks 5 after a minute description of each por-
tion of the tegumentary apparatus, he concludes :
u I shall here only observe further, that my inves-
tigations seem to be in complete opposition to the
theories which make the shell of the Crustacea an-
alogous (homologous) to the scaly epidermis of
Serpents and Lizards. I see no analogy (ho-
mology) between the shedding of the shell of the
Crustacea, — which divests them of organs des-

1 We are indebted to Valentin for the re-
searches, few as they are, which have hitherto
been made on the internal structure of the skele-
ton of Crustacea ; see his Repertor. f. Anat. u.
Physiol. I. 1836, p. 122.

Lavalle is about to publish microscopical re-
searches on the structure of the cutaneous skeleton
of the Decapoda: see Ann. d. Sc. Nat. 1847, p.
352.*

tined to give the body its form and volume, to
serve as points of attachment to the locomotor
muscles, to furnish the instruments of prehension
and mastication 5 organs placed not only on the
surface of the body, but often immersed in the
midst of soft parts, and in which we find an organ-
ization such as I have described, — and the peri-
odical shedding observed in reptiles of a thin
epidermis, without consistency, completely unor-
ganized and incapable of fulfilling any of the
uses to which the shell is destined. My re-

310

THE CRUSTACEA.

$ 265.

numerous very thin layers, made up of very fine, interlaced fibres. How-
ever, sometimes this fibrous texture is scarcely distinguishable, and often
the lamellae are perfectly homogeneous. Frequently, also, these lamellae
are traversed, either in a parallel or perpendicular direction, by canals,
which are often so small that, seen under the microscope by reflected light,
they appear only as lines or black points.® In some species, this skeleton
has a distinct cell-structure; for the skin, here and there, has the aspect of
a net-work composed of numerous round, or polyhedral meshes.

This net-work is, undoubtedly, the result of the fusion of the walls of
numerous cells lying on the same plane. In the calcareous shells, the
carbonate and phosphate of lime is so intimately combined with the chi-
tine, that their particles, as such, cannot be distinguished.® In those
portions of the skin which serve a respiratory function, the calcareous
matter is always wanting.

The pigments are due to very fine granules which exist either as such in
the cutaneous lamellae, or are so thoroughly fused in these last, that they
are indistinguishable. In some cases, these granules are contained in
polyhedral cells which form a simple layer under the transparent skin; in
others, radiating pigment cells, isolated, or reticulated, are seen through
the colorless skin. The red, green, or blue color of many of the lower
Crustacea, is due to oil-globules in the interior of the body, which are seen
through the transparent integument.®

The tubercles, points, bristles, single or bifid hairs, which are usually
hollow and exist on the surface or borders of different parts of the cutane-
ous skeleton, are always mere prolongations or simple excrescences of the
integument, and contain its characteristic substance, — Chitine.

With Crustacea, as also with the other Arthropoda, the cutaneous
envelope, whatever may be its tenuity — as for instance on the respiratory
organs, is never covered with ciliated epithelium.® This absence of vibratile
organs is due, probably, to the presence of chitine.

The internal surface of this envelope is usually lined with a peculiar,
thin, fibrous membrane, analogous to an internal periosteum. In the
moulting process, which is common to all Crustacea, it plays an important
part, for it probably secretes, in layers, the materials for the new envelope.

§ 265.

Beside the cutaneous skeleton, there is, with the Cirripedia, an envelope,
entirely resembling the mantle and the valves of the Acephala.

2 Astacus , Apus , Julus , and Glomeris. But
in the last two of these, the cutaneous canals are
pretty large and consequently have not the appear-
ance of black lines.

3 According to Falentin (loc. cit. p. 124), the
cutaneous canals of the Astacus Jluviatilis are
tilled with carbonate of lime, a point which I have
not had the opportunity to confirm.

4 Cyclops , Cyclopsina, and other Entomos-
traca.

3 Templeton (Trans, of the Entomol. Soc. I. p.

searches have convinced me of the vitality
of the shell, at least in the first period of its exist-
ence •, and in reference to this, I am fully of
Cuvier’s opiuion, when he said, in his 1 Anatomie
Compare, ’ ‘ The envelope of the Crustacea is at

195, PI. XXI. fig. 9, a. b.) has observed with Cala -
nus arietis (an animalcule allied to Cyc/opsina
castor), two bristles at the extremity of each of the
long antennae, and which, he says, are provided
with a row of vibratile cilia. But this observation
does not invalidate what I have remarked in the
text, for how often have ciliary phenomena been
observed on organs which really have no such
appendages. I doubt if this observation of Tem-
pleton will be confirmed by other observers.

first, soft, sensible, and even furnished with ves-
sels, but a quantity of calcareous mole soon collects
there, hardens it, and obstructs the pores and ves-
sels ; see loc. cit. p. 376, also Comp. rend. 1847,
XXIV. p. 12. — Ed.

§ 266.

THE CRUSTACEA.

311

The body of these animals, as well as its articulated appendages, are
enclosed in a cutaneous skeleton containing the chitine ; and, moreover, is
enveloped in a peculiar mantle having, externally, calcareous plates which
vary in number and are so united together as to be movable in some
species, and fixed in others. With the Lepadea, the mantle is prolonged
into a kind of siphon.^ Not only this mantle, but also its ligaments
uniting the movable pieces of the shell and the siphon, are composed of a
lamellated tissue analogous to that of the proper cutaneous skeleton, and
like it also, contain chitine. It is covered with a thin layer of dark-
colored pigment cells.

But the valves of the Cirripedia differ essentially from the calcareous
shell of the other Crustacea. In the first place, they have no participation
in the moulting, to which the cutaneous skeleton and the mantle are regu-
larly subjected ;(1) then again, their structure and chemical composition
resemble that of many of the Bivalvia.® The valves of the Balanoidea
form the only exception in this respect. They are traversed, in part, by
numerous parallel tubes, dilated at their inferior or their external portion,
which pursue a vertical course in the vertical valves, but are radiated in
the horizontal plate. These tubes, which are wanting in the movable oper-
cula of these shells and in the transversely-striated valves which, in the
genus Balanus , are intercalated between the longitudinally-striated ones,
are often laterally compressed, and their interior has imperfect longitudinal
septa, or is even divided into several chambers by transverse partitions. (3)
The horizontal plate which forms the base of the shell, is perforated cen-
trally, and hollowed on its under surface, with the genus Coronula. This
cavity is divided, by numerous vertical and symmetrically-arranged septa,
into compartments filled with a fibrous substance. (4) With Tubicinella. this
plate is entirely wanting, and is replaced by a fibrous substance. This
fibrous matter, by which Coronula and Tubicinella are fixed firmly to
foreign bodies, is comparable to the pedicle of the Lepadea, which has
become internal and overgrown by the shell.

The increase of the shells of Cirripedia follows the same laws as that
with the bivalve or multivalve mollusca, judging from the course of the
lines of growth which they present.

§ 266.

The form and number of the different segments of the cutaneous skele-
ton, which are sometimes extraordinarily developed, and sometimes equally

l Thompson (Zool. Research. &c. p. 79, PI. X.
fig. 1), has observed with Balanus pusillus , that
the Cirripedia, like the other Crustacea, cast off
their entire skin at certain seasons. I have my-
self often seen this animal deprived of its skin with
all the appendages, and even the mantle which
lines its shell. In captivity, these little animals re-
peat this process at irregular and often very short
intervals, as in twelve, eight and even five days.

* l $ 265.) With the Anatifae, the siphon or
pedicle corresponds to a pair of antennae in the
young •, the animal attaches itself by the sucker-
like disc terminating these organs, before the meta-
morphosis commences, and in a group of these
animals all the different stages may he observed,

2 See Schmidt , loc. cit. p. 60.

3 See Poliy loc. cit. Tab. IV. fig. 6-10 ; Rapp ,
in Wiesmann's Arch. 1841, I. p. 168 ; and Cold-
stream, in the Cyclop, of Anat. loc. cit. p. 685.

1 For Coronula diadem i and ba/aenarisy see
Chemnitz , Neues Conchj lien-Cabin. VIII. p. 319,
Taf. XCIX. fig. 841, 846 ■, Lamarck , Ann. du
Mus. d. Ilist. Nat. I. p. 461, PI. XXX. fig. 3, and
Burmeister , Beitrage, &c., p. 34, Taf. I. fig. 2, 3.

from the pair of distinct antennae to the fixed sim-
ple pedicle •, see Dana , Notice of some Genera of
Cyclopacea, Silliman's Jour. Vol. I. 2nd Ser. p. 225,
note, also Rep. on Crustacea, Ex.Exped. of the U.
S. p. 1393. — Ed.

312

THE CRUSTACEA.

§ 267

abortive and fused several together, — serve, in descriptive zoology, to char-
acterize orders, sub-orders, families, and genera ; consequently they need not
be mentioned here/1'

With many Crustacea, the internal surface of the skeleton in widely
different parts of the body, has prolongations and processes of the most
manifold form ; some of these serve as points for the insertion of muscles
and tendons, and others as partitions separating and shielding particular
organs.

CHAPTER II.

MUSCULAR SYSTEM AND ORGANS OF LOCOMOTION.

§ 267.

The voluntary muscles of Crustacea are composed exclusively of trans-
versely-striated fibres, and are, moreover, perfectly colorless/1'

They are always inserted upon the interior of the skeleton, either
directly, or by means of its prolongations. These last are often very long,
resembling tendons ; from which, however, they differ in their intimate
structure and chemical composition. They are composed of straight, paral-
lel, flattened fibres, and show their direct relations with the cutaneous
skeleton by containing chitine.

The isolated muscles have usually a riband-like form,* and are especially
accumulated in those regions of the body displaying great power or
extensive movements. There are, therefore, for their reception, cavities or
large canals in certain parts of the skeleton. Generally, the flexors are
upon the ventral, and the extensors on the dorsal surface of the body.
The first are always larger and more powerful than the second. Usually,
the muscles pass from one segment to the adjacent one, and by this
arrangement, the interarticular movement between the segments is pro-
duced. Their course is longitudinal, but, especially where there are
several superposed layers, they assume also an oblique and crucial direc-
tion.® Rarely are transverse imaseles observed.®

The muscular system in general is very unequally developed in the
various orders of Crustacea. It is most complicated when the number of

1 See Savigny , M6m. &c. part I. and Erickson ,
Entomograph. Hft. 1, 1840, p. 1, Taf. II.

1 For the muscles of Astacus , see Will, in Mai-
ler's Arch. 1843, p. 358.*

2 In the tail of many Decapoda, and in the ab-
dominal segments of Myriapoda.

* [§ 267, note 1.] For researches on the inti-
mate composition of the muscular tissue with Crus-
tacea ( Argulus , Artemia , Branchipus ), see Ley-
dig , loc. cit. Siebold and Kolliker's Zeitsch. II. p.
327, III. p. 301). The fibres of muscles can often
be easily separated into fibrillae which appear to
consist of piles of discs exactly as with some of the

3 With the Myriapoda, the transverse muscles
pass off right and left from the ventral median line
to the sides of the abdominal segments. With the
Lernaeodea, and Ergasilina, there are, under the
skin, transverse as well as longitudinal muscles.

other Arthropoda, and especially the Insecta, under
which, this point will be specially treated. — Ed.

* [ § 267.] For a circular muscle quite extraor-
dinary in Caligus , see Dana , Descript, of a specie3
of Caligus, Amer. Jour, of Sc. XXXIV. p. 247, PI.
IV. fig. 7, r.— Ed.

§ 268.

TIIE CRUSTACEA.

313

the segments of the body is greatest ;(4) and most simple when these seg-
ments are atrophied or blended together.®

§ 268.

The locomotive organs of the Crustacea are, in general, very numerous ;
for, often all the segments, from the head to the extremity of the tail, that
is, the three corresponding to the thoracic segments of insects, and those
of the posterior part of the body, have, each, a pair of articulated append-
ages. In the order Myriapoda, the Chilognatha have two pairs of legs on
each segment of the body.® The form of these organs may be most vari-
ously modified, and even so much so that their function is entirely changed.®
But those of the first five segments of the abdomen are most constant in
their form ; although they change their function, being sometimes ambula-
tory legs, sometimes prehensile organs, and sometimes oars. When prehen-
sile organs, their last joint is armed with a very hooked, sharp claw; when
oars, this same joint becomes a plate bordered with stiff bristles or bifid hairs.

The locomotive organs of the three thoracic segments are usually pressed
towards the mouth and changed into foot-jaws, which serve either as masti-
catory, or as tactile and prehensile organs. The appendages of the pos-
terior part of the body may have even yet wider variations. They may be
changed into false or abdominal feet serving sometimes as oars, as fins, or
as respiratory organs ; and, in the act of generation, they may play the
part, some, of copulatory organs, and others, as porters of the eggs.

When they are ambulatory, or when prehensile organs, these appendages
may be divided into six pieces, viz. : The Coxa , the Trochanter , the Femur ,
the Tibia , the Metatarsus, and the Tarsus the extremity of which, with
the ambulatory feet, is often prolonged into a short, stiff claw. When they
serve as natatory organs, the separate joints are more or less flattened and
spread out. When used as prehensile organs, they are cither monodactyle
— the entire tarsus being transformed into a strongly-curved hook which
can be applied against the metatarsus, — or they are didactyle or like
pincers, — the metatarsus being thickened or increased in a hand-like man-
ner, and prolonged into an immovable process (Index), against which the
tarsus (PolUx) can be applied in a finger-like manner.

From these metamorphoses and the complete abortion of these append-
ages, the various forms of Crustacea may be reduced to a few principal
types, as follows :

4 The muscular system is highly developed with
Decapoda, Stomapoda, Amphipoda, Isopoda,
Myriapoda, Poecilopoda and Phyllopoda ; see
Geveke , De Cancri astaci quibusd. partib. p. 7,
fig. 1-7 *, Suckou Anat. physiol. Untersuch. loc.
cit. p. 04, Taf. IX. X. ( Astacus Jluviatilis) ;
Milne Edwards , Hist. Nat. d. Crust. I. p. 155,
PI. XIII. ( Hnmarus marinus) ; Kutorga , Scolo-
pendr. morsit. Anat. p. 12, Tab. II. fig. 1, 2 ; Van
der Hoeven , fyecherch. sur Phist. nat. et l’anat. d.
Limulus, p. 24, PI. III.; Zaddach , De Apodis
cancriformis Anat. p. 4, Tab. I. III.

The abortion of the muscular system is often
so extensive in the lower parasitic Crustacea, that,
beside the few muscles belonging to the tactile
and locomotive organs, there are found only seme
longitudinal and transverse fibres under the skin ;
Bee Nordmann , Microgr. 13eitrftge, lift. 2, p. G,
Taf. I. V. VII. ( Lamproglena , Adheres and

27

Tracheliastes) , Rat hit, in the Nov. Act. Nat.
Cur. XIX. p. 141, Tab. XVII. fig. 2. 3 ( Dicheles -
tium ) ; Pickering and Dana , in the Isis, 1841,
Taf. IV. (Cali gus).

1 This anomaly, in which the three segments back
of the head do not participate, is due, perhaps,
to the segments of the body being always fused in
twos.

2 In the interpretation of the movable1! append-
ages, I have relied for the most part on the princi-
ples of Erickson (Entomograph. loc. cit.), for they
appear most consistent and unconstrained. In the
instances where, at first sight, they appear un-
warranted, they may be very well explained by
recourse to the phenomena of development of
Crustacea ; and by this me^ns, here, especially,
where the metamorphoses occur gradually and
continuously, may be found the solution of many
obscure questions in morphology.

314

THE CRUSTACEA.

§ 268.

1. With the Myriapoda, these appendages are ambulatory ami have the
same form with all the segments of the body ; and only with the Chilopoda
the anterior and middle pairs of the first segment corresponding to a
thorax, are changed into tactile organs.

2. With the Isopoda, Laeinodipoda, and Amphipoda, the first thoracic
pair are tactile organs. With the Amphipoda, the second and third
thoracic pairs are changed into prehensile organs armed with a claw. The
five anterior abdominal pairs are ambulatory and unchanged, with the Iso-
poda, and Amphipoda. But the remaining posterior pairs are transformed,
with the first of these orders, into lamelliform respiratory organs; and with
the second, into short, very movable appendages, terminated, each, by a
double uni- or multi-articulate cirrus, which serve sometimes as oars, some-
times as gyratory organs.

3. With the Decapoda, the thorax is entirely abortive, and its three
pairs are changed into oral and tactile organs ; while the first pair, belong-
ing to the anterior abdominal segments, is usually transformed into a for-
ficulate prehensile organ. The four succeeding pairs are simply ambulatory
organs. But the appendages of the posterior part of the abdomen are re-
duced to tendril-like processes, which play a part in the act of generation.

With the Squillina, the three thoracic, and the first two abdominal pairs
have the form of prehensile organs, while the three succeeding pairs retain
their character of ambulatory organs, and those of the remaining posterior
seo-ments are changed into lamelliform fins.

4. In the section of the inferior Crustacea, designated usually under the
name of Entomostraca, the head and thorax are fused into a single part
called Cephalothorax, and the mouth is situated so far behind, that the first
pair of feet is in front of it. The locomotive apparatus here consists
usually of oars or prehensile organs. With the Poecilopoda, the first
three pairs of appendages are forficulate, as, also, are the three pairs of
jaws. With the Phyllopoda, and Lophyropoda, the first two pairs of feet
resemble antennae ; of these sometimes the first, as well also as the second,
which are usually branched, serve as oars; (3' here, also, the often very
numerous, anterior abdominal appendages are used usually as fins, while the
posterior ones are scarcely at all developed.

5. With the Cirripedia, the first thoracic pair is transformed in a
remarkable manner. With the Lepadea, they are changed into a soft
foot; and with the Balanodea, into a shell. (4) The remaining six pairs
are multiarticulate cirrate organs, and the abdomen is prolonged into a tail
free from appendages. The three anterior pairs of these cirrate organs are
the shorter, and have a tactile function ; while the three posterior are used
as gyratory organs.

6. With the Siphonostoma, the mouth is even still further behind, and

3 With Cyclops , Cyclopsinay and Cypris , it is
the first pair of feet that is transformed into oar-
like organs, but it is the second with Apus , Lim-
nadia , Daphnia , and Polyphemus.

With the Branchiopoda, the disposition is quite
different. The anterior pair is changed into two
slightly movable appendages, hook-like or digiti-
form, and rolled spirally. With the embryos and

♦ [ § 268, note 3.] The first pair of feet is, gene-
rally, the second pair of antennae. For a full dis-

the young animals, these organs are used clearly as
oars •, see Jurine , Hist. d. Monocles, loc. cit. PI.
XX. fig. 9, and PI. XXI. fig. 1, cl{Chirocephalus)y
and Joly , in the Ann. d. Sc. Nat. XIII. PI. VII.
( Artemia ).*

4 See Thompson , Zool. Research. PI. IX. fig. 3
( Tialanus ), and Burmeistery Beitr., &c., Taf. I.
fig. 3-5 ( Lcpas ).

cussion of this point, see Dana} Report on Crustac.
&c. p. 1031. — Ed.

§ 269.

THE CRUSTACEA.

S15

the number of appendages much less ; so that the three and only pairs,
corresponding to the thoracic, are in front of the mouth. With the Cali-
gina, and the Ergasilina, the thoracic appendages are prehensile organs,
while those of the abdomen are changed into rudimentary oars. With the
genus Argulus alone, the first abdominal pair has the form of suckers,*
the remaining ones being fin-like as usual. With the Lernaeodea, the ab-
dominal appendages are entirely wanting, and there are only a few anterior
prehensile ones, two of which, in some genera, are prolonged arm-like, and
united, at their extremity, into a button-like, suctorial organ.® Sometimes
these arms are wanting, there being present only the suctorial organ.®
With the Penellina, the locomotive organs are reduced to non-articulated
rudiments ; or even these may be wanting, and then the cephalic extrem-
ity of the unsegmented body has stiff, forked, horny, processes, by means
of which these parasites enter the parenchyma of other animals. (7)

§ 2G9.

Certain Crustacea have, moreover, a special locomotive apparatus.
With Cypridina, the body is shielded with a bivalve shell, the halves
of which move on a kind of hinge. Upon their internal surface are inserted
muscular fibres, arising from the back of the animal, which act like the
adductor muscles of the bivalve Acephala.

With the Cirripedia, there is a considerable transverse adductor muscle,
which, with the Balanodea, and Lepadea, is situated in the anterior or
cephalic angle of the fissure of the mantle, which is nearly always closed
by an operculum. (1) In this same angle, the body, with all the Cirripe-

dia, is in connection with the mantle, partly by its cutaneous envelope,
which, at this point, is folded in so as to line the cavity of the mantle, and
partly by various muscles. These muscles arise from the anterior extrem-
ity of the body, which is inverted within the cavity of the mantle, and from
both the ventral (or upper), and from the dorsal (or lower) surface of the
animal.

When those of the upper or abdominal surface are contracted, and, at
the same time, the adductor muscle of the valves is relaxed, the animal
comes out through the fissure of the mantle ; but it is withdrawn into
the mantle-cavity when those of the lower or dorsal surface are con-
tracted.®

5 Tracheliastes, Achtheres , Brachiella.

0 Anchor eLla.

7 Lernaea , Lernaeocera.

1 Poli, loc. cit. Tab. IV. fig. 3 J. *, Cuvier , Mem.
&c. p. 5, fig. 2, 7 e. 11 A, and Martin St. Ange ,
Mdm. &e. p. 15, PI. II. fig. 18, S.

* [ § 268.] For a very complete description of
these sucker-like organs, with excellent figures, see

2 Po/z, loc. cit. Tab. IV. fig. 13, y. z. 17 Cu-
vier, loc. cit. p. 5, fig. 18 b. b., and Martin St.
Ange} loc. cit. p. 14, PI. II. fig. 17, 19, J.

Dana, Amer. Jour. Sc. XXXI. 1837, p. 297, and
Rep. on Crustac. Ioc. cit. p. 13, 18. — Ed.

316

THE CRUSTACEA.

$ 270.

CHAPTER III.

NERYOTJS SYSTEM.

§ 270.

The Nervous system of the Crustacea, is developed in different de-
grees according to the various orders.01

Its central mass consists of an abdominal cord, connecting, usually, with
the cerebral ganglia by an oesophageal ring. With the long-bodied species,
this abdominal cord is composed of numerous ganglia, arranged in succes-
sive pairs from before backwards, and connected together by longitudinal
commissures. But when the cutaneous skeleton is shortened by a dimi-
nution or a fusion of the segments, the ganglionic chain is lessened in a like
manner by a coalescence or a disappearance of several of its ganglia.

With the Macrura, the Stomapoda, the Amphipoda, and Isopoda, the ab-
dominal cord consists of ten to thirteen pairs of unequal ganglia, situated,
usually, on the median line, and shielded by septa given off from the inter-
nal surface of the thoracic and abdominal segments of the skeleton.

The size of these ganglia is in direct ratio with the development of the
segments and their appendages, to which they belong. Those of the
thorax, — the anterior abdominal ones, as well as the last caudal one, are
consequently very large, for they send filaments to the various chelate,
prehensile, ambulatory, and natatory appendages, and to the caudal lam-
ellae, which are usually highly developed. With the Myriapoda, the ab-
dominal cord is remarkable for the great number of its ganglia, which are of
equal size. Quite often, the ganglia of the same pair are fused into a
single mass ; in which case, the two interganglionic commissures are more or
less approximated or even blended together. With some species, a portion
of the abdominal ganglia are so closely approximated, successively, that the
interganglionic commissures are wholly wanting. With the Brachyura, the
whole abdominal cord is concentrated into a large central mass.

The peripheric nerves arise from the ganglia, rarely from the intergan-
glionic commissures. The cerebral mass, which is situated above or in
front of the oesophagus, is composed of a pair of considerable ganglia,
more or less fused together. The nerves sent off from these, go princi-
pally to the organs of sense ; and in the inferior Crustacea, where these last
are wanting, the cerebral mass is absent also. In such case, there are
usually wanting likewise the two cerebral commissures, which are given
off from the anterior thoracic ganglion, and surround the oesophagus.*

1 Audouin and Milne Edwards (Ann. d. Sc. Milne Edwards , Hist. Nat. d. Crustac. I. p. 126,
Nat. XIV. 1828, p. 77, PI. II. -VI.) have given a PI. XI., and his article Crustacea in the Cyclop-
general review of the disposition of the nervous sys- of Anat. loc. cit. p. 762.
tem in the different orders of Crustacea 5 see also

* [ End of § 270.] It is regretted that no example,
illustrative of this last statement, is given, for
certainly none is now recollected where the grand
typical structure is not present, — in other words,
where the oesophagus does not pierce the cerebral
nervous system at some point. In many of the

inferior Crustacea, such as Caligus , and some of
not all of the Cyclops tribe, the cephalic, thoracic,
and abdominal ganglia, are fused into a single
mass through the anterior part of which the oesopha-
gus passes *, see Dana , loc. cit. Caligus. Amer. Jour.
Sc. XXXIV. p. 250. — Ed.

§§ 271, 272.

THE CRUSTACEA.

317

§271.

The intimate structure of the nervous system in many of the orders of
Crustacea, can be made out without difficulty, by dissection and the micro-
scope;0' for its elements are not as liable to change as in the other classes
of the Invertebrata already described.

In many species, there may be observed in the nerves surrounded by a
delicate fibrous neurilemma, the primitive nerve-fibres so large that their
double contour is easily seen ; but these gradually assume a varicose as-
pect.® In the ganglia, the ganglionic globules may be easily seen, as
very large, round, and sometimes pyriform cells, having each a dispropor-
tionately large nucleolated nucleus.® As to the course and arrangement
of the nerve-fibres in the interior of the abdominal ganglia, two kinds of
these fibres may sometimes be distinguished : the first pass uninterruptedly
through all the ganglia successively, and thus contribute to the formation
of the longitudinal commissures ; but the second pass round among the
ganglionic globules, and emerge laterally from the ganglion to form the
peripheric nerve.®

§ 272.

From a more particular examination of the arrangement of the nervous
system in the different orders of Crustacea, the following remarkable facts
have been noticed.®

With the Macrura, where this system is most highly developed,® the
abdominal cord is composed of twelve pairs of ganglia, generally blended

1 See Helmholtz , De fabric, syst. nerv. everte-
brat. loc. cit. p. 17.*

2 Ehrenberg , Unerkannte Struct. &c. p. 56,
Tab. VI. fig. 3-5 ( Homarus marinus , Astacus
Jluviatilis and Palaemon squilla). The vari-
cose enlargements are represented too regular in
some of these figures. See, also, Hannover , Re-
cherch. &c. p. 68, Tab. VI. fig. 76, c. e.

3 Hannover , loc. cit. p. 67, fig. 75, 76 a. (Asta-
cus Jluviatilis), and Valentin , in the Nov. Act.
Acad. Nat. Cur. XVIII. p. 210, Tab. IX. fig. 72-
85. This last author declares that he has observed,
in the abdominal ganglia of the common crawfish,
the ganglionic globules divided symmetrically into
two groups, right and left •, and in the caudal gan-
glia of the same species, that he has seen two double
groups, two anterior and two posterior.

4 Valentin (loc. cit. p. 211) has seen these two
kinds of primitive fibres in the abdominal cord of
the common crawfish. We are indebted to New-
port for very complete observations on the disposi-
tion of the nervous fibres in the abdominal cord of
Myriapoda, and illustrated by numerous figures *,
see Philos. Transact. 1843, p. 243, PI. XI., or in
abstract in Froriep's neue Notiz. XXVIII. p. 177,
or in the Ann. d. Sc. Nat. 1. 1844, p. 58, or Annals of
Nat. Hist. XII. p. 223. According to this observer,
four fasciculi of primitive nerve-fibres may be ob-
served in the ventral cord of the Myriapoda. An
upper and a lower, extending longitudinally, con-
tain the one, motor, and the other, sensitive fibres.
A third is composed of transverse fibres which
pass from one side of the ganglion to the other *, and

* [ § 271, note 1.] See, also, for histological details
on this system, Ley dig , loc. cit. Siebold and Kol -

27 *

the fourth extends from one ganglion to the next
succeeding, by the side of the longitudinal commis-
sures. To these last, Newport has given the name
of Jibres of reinforcement. Each peripheric
nerve given off from the abdominal cord, contains
fibres from all of these four fasciculi. The associate
and reflex motions between the feet of the same
pair, are due to the transverse fibres, and the sym-
pathy between the posterior and anterior feet is
referable to the fibres of reinforcement.

1 If, in proceeding from the higher to the lower
species in the description of the nervous system, I
have deviated from the plan hitherto pursued, it is
because, with the Crustacea, this system, notwith-
standing the various forms of the body, is found
upon one and the same type, which is not true in
any of the preceding classes, as, for instance, in
the Acephala. This type is especially apparent
during the young age of these animals, and does
not change except from their ulterior metamor-
phosis, when, often some portions of the nervous
system disappear *, on this account, this last will be
best understood when studied in its primitive state,
or from the more perfect forms it presents in the
higher Crustacea.

2 For the nervous system of the macrourous
Crustacea, seeAudouin and Milne Edwards , loc.
cit. ( Homarus , Palaemon, and Palinurus ) ;
Suckow, loc. cit. p. 61, Taf. XL fig. 7 (Astacus) ;
Brandt, Medizin. Zool. I. p. 64, Taf. IX. fig. 1,
and especially Newport, Philos. Trans. 1834, p.
406, PI. XVII. fig. 40-42 (Homarus).

Ulcer's Zeitsch. II. p. 328, III. p. 291 ( Argulus ,
Artemia, Branchipus). — Ed.

318

THE CRUSTACEA.

§ 272.

together laterally, on the median line. Of these, the first six pairs, belong-
ing to the thoracic and to the anterior abdominal segments, are the larger,
and send off nerves principally to the foot-jaws, to the prehensile, and to the
ambulatory organs. The two longitudinal commissures between the anterior
abdominal ganglia, are separate; but those between the posterior ganglia are,
on the contrary, blended into a single cord. In some species, these com-
missures are wholly wanting between the anterior ganglia.® The brain
consists of a single transverse ganglion ; from its front and sides pass off
several nerves for the antennae, the olfactory organs, the eyes, and the
auditory organs; while, from behind, it sends off the two long cords which
surround the oesophagus. These last give branches on their course to the
organs of mastication, and interanastomose behind the oesophagus, just
before reaching the first thoracic ganglion, by a transverse filament.®

With the Stomapoda, the nervous system is composed of a cerebral gan-
glion, and of about ten abdominal ganglia ; of these, with the Squillina, the
last six belong to the tail, while the remaining four, anterior, send nerves to
the thorax, and to the first three abdominal segments. The size of the first,
which sends nerves to the prehensile feet, , is due to its being composed
of several ganglia fused together.® With the Mysina, the five or six
largest ganglia belong to the thorax and to the anterior part of the abdo-
men, and are connected together by short, double commissures.®

The genus Phyllosoma has two extraordinarily long and very small
oesophageal cords extending from the brain to the abdominal cord. The
thoracic portion of this last is composed of three pairs of ganglia, blended
almost into a single mass ; these are succeeded by six pairs of large ab-
dominal ganglia, arranged in two longitudinal rows, and interconnected by
six very short, transverse filaments. In the short tail, there are, more-
over, six pairs of ganglia, smaller and laterally contiguous, but connected
successively by very small longitudinal filaments.®

With the Anomoura, which resemble the Brachyura in the abortion of
the post-abdomen, the structure of the nervous system confirms this affin-
ity. With Pagurus, the anterior portion of the abdominal cord consists
only of three ganglia, which send nerves to the foot-jaws, to the cheliform,
and to the partially abortive ambulatory feet. But the posterior part of
this cord consists of two cords which arise from the third abdominal gan-
glion, and unite, just in front of the arms, in the fourth and last gan-
glion.® With the genus Homola, the five pairs of the anterior abdomi-
nal ganglia are fused into a single mass which is perforated through its
centre. From the posterior border of this mass a simple nervous cord
as rudiment of the posterior part of the ventral cord, passes off to the wholly
abortive post-abdomen. ®

With the Brachyura, the nervous system has only two central masses,
one cerebral, the other abdominal. The first sends nerves, as in the other

3 Palinurus, and Palaemon ( Audouin and
Milne Edwards; ioc. cit.). In these two Crusta-
cea, there is only a small fissure in the centre of
the principal ganglionic mass, after the fusion of
the ganglia.

4 This transverse filament is absent neither with
Palaemon , Palinurus , nor with Hornarus , and
Astacus. It was overlooked by Suckow in the
crawfish, although distinctly seen by Brandt ; see
his Medizin. Zool. Ioc. cit., and his Bemerkungen
fiber die Mundmagen-nerven, loc. cit. Tab. I. fig.
1, 2 E., or Ann. il. Sc. Nat. V. 1836, PI. IV.

5 Cuvier , Logons &c. III. 1845, p. 330, and
DelLe Chiajc , l)escriz. &c. Tav. LXXXVI. fig.
5.

G Frey, De Mysidis flexuosae anat. p. 9.

7 Audouin and Milne Edwards , Ann. d. Sc.
Nat. loc. cit. p. 81, PI. III.

6 Cuvier, Leg ms, &c., loc. cit. p. 329; and
Owen , Lect. on Comp. Anat. p. 170.

9 Milne Edwards , Ilist. Nat. d. Crust. PI. XI.
fig- 9.

§ 272.

TIIE CRUSTACEA.

319

Decapoda, to tlie organs of sense; the second is large, round or oval, and
situated in the centre of the thorax, — it is sometimes perforated cen-
trally/10’ and supplies all the nerves of the trunk, beside sending off' the two
oesophageal cords. These cords are connected by the transverse commissure
already mentioned, and give off filaments to the organs of mastication.
From the posterior extremity of the cord, there arises a simple nervous
trunk, free from ganglia, and extending along the median line to the very
extremity of the tail/11’

Among the Amphipoda, the Gammarina have a brain scarcely larger
than the first of the abdominal ganglia; these last, twelve in number,
are connected by double commissures, and the posterior ones belonging to
the segments of the body which have false feet, are always smaller than
the others/12’ With the large-headed Hyperina, the two cerebral ganglia
are considerably larger than the abdominal ones, which are ten in number,
and of unequal size. Their commissures are contiguous, and the first gan-
glion, which is the largest, is probably the result of the fusion of two
pairs/13’

With the Isopoda, the abdominal cord, which is connected with the cere-
bral ganglia by two short oesophageal cords, is composed of seven pairs of
ganglia, situated in the thoracic and anterior abdominal segments, and con-
nected together, successively, by double commissures. In some genera, the
posterior ganglia send off radiating nerves to the partially abortive and
partially fused terminal segments/14’ In others, these seven pairs are
succeeded by five or six pairs of others, smaller, and which, with Iclothea,
are connected together by double commissures;05’ but with the genera
Cymothoa ,(10’ Aegaa7) and Lygidium ,<w> are contiguous. With many Iso-
poda, the peripheric nerves are given off, not only from the ganglia, but
also from their longitudinal commissures, and the posterior ones are distrib-
uted to the dorsal region of the animal/19’

With the Lacmodipoda, the abdominal cord is composed of eight pairs
of ganglia, of which the first two arc situated in the cephalic segment, one
behind the other, and send off nerves to the organs of mastication, and to
the first pair of feet, — thus corresponding to the result of the fusion of the
first two thoracic segments with the head. The other pairs are connected
by very distinct double commissures, which, between the last two pairs, are
quite short, thus bringing the last three pairs almost together in the third
terminal segment of the body/20’

With the Myriapoda the ganglia of the abdominal cord are very numer-
ous, and nearly all of the same size. The brain consists, usually, of a

19 Maia squinado.

11 Audouin and Milne Edwards , Ann. d. Sc.
Nat. loc. cit. p. 91, PI. VI., and Milne Edwards ,
Hist. Nat. d. Crust. I. p. 141, PI. XI. fig. 5, 10
( Maia squinado and Cancer maenas).

12 Audouin and Milne Edwards , loc. cit. p.
79, PI. II. fig. 1, and Milne Edwards , loc. cit. p.
129, PI. XI. tig. 1 ( Talitrus ).

1-3 Straus , Mem. sur les Hiella, in the Mem. du
Mus. d’llist. Nat. XVIII. 1829, p. 60, PI. IV. fig.
16 ( Hyperia ).

14 Treviranus , Verm. Schrift. I. p. 63, Tab.
IX. fig. 63 ( Porcellio scaber ) ; Brandt , Medizin.
Zool. II. p. 75, Tab. XV. fig. 23 ( Oniscus mura-
rius ), and Rathki , De Bopyro et Nereide, p. 14,
Tab. III. fig. 4 ( Bopyrus squillarum).

15 Rathki, Danzig. Schrift. loc. cit. p. 127, Tab.
IV. fig. 2 ( Idothea entomon).

16 Audouin and Milne Edwards, loc. cit. p. 83,
PI. II. fig. 2, and Milne Edwards , loc. cit. PI. XI.
fig. 2.

17 Rathki , Nov. Act. Nat. Cur. XX. Pt. I. p. 33,
Tab. VI. fig. 15.

1* Lereboullet , Ann. d. Sc. Nat. XX. p. 124, PI.
V. fig. 24.

19 Porcellio , Oniscus , Armadillidium, Ido-
thea.

^0 Treviranus , Vermisch. Schrift. II. p. 8, Taf.
I. fig. 5, and Roussel de Vauzime, Ann. d. Sc.
Nat. I. p. 253, PI. IX. fig. 19 ( Cyamus ).

According to Frey and Leuckart (Beitr. p.
102), the ventral cord of Caprella somewhat re-
sembles that of Cyamus.

320

THE CRUSTACEA.

§ 272.

distinct right and left half, upon each of which is a kind of Ganglion
opticum, of a size proportionate to that of the development of the eyes.
With the Chilopoda, the abdominal ganglia are widely separated from
each other, but connected by double commissures which are closely ap-
proximated, and in some cases, fused together as a ventral cord.*-1* With
Litkobius, and Scutigera, there are sixteen pairs of these ganglia ;• with
Scolopendra, twenty-two, and with Geophilus, fifty to one hundred and
forty. Of these ganglia, the first pair, belonging to the two anterior feet,
which are changed into prehensile or tactile organs, are much the largest.
The size of the others corresponds, for the most part, to the development
of the feet/22’

Of the Chilognatha, the genus Polydesmus, the long feet of which are
widely separated, is allied to the preceding section of Myriapoda. Above
each two pairs of feet, the abdominal cord is enlarged into two successive
ganglia, and the medullary mass between them corresponds to a simple
longitudinal commissure/28’ With the other Chilognatha, of which the
pairs of feet are close together, the longitudinal commissures are wholly
wanting, so that the ganglia, of a number corresponding to that of the
pairs of feet, form a moniliform cord ; and in some Julidae, the constric-
tions of this last are entirely effaced/24’

The disposition of the nervous system of Limulus is remarkable. Its
principal mass surrounds the mouth like a ring. From the anterior por-
tion of this, corresponding to a brain, pass off nerves in front, among which
the two optic nerves are conspicuous for their length ; while its posterior
arc, which surrounds the oesophagus, has three transverse commissures suc-
ceeding each other. From the lateral portions of this ring, pass off six
pairs of large nerves for as many pairs of prehensile feet. From its pos-
terior border arises a large trunk composed of two bands which extend
backwards along the median line of the abdomen, furnishing nerves to the
fin-like and gill-like appendages, and then separating, terminate in the tail
in a ganglion from which are given off many filaments to the neighboring
parts, and a very long one which enters the caudal spine/25’

Of the nervous system of the Phyllopoda, that of the genus Apus is the
best known/28’ The bx-ain consists of a flattened, quadrilateral body, from
the superior angles of which arise the optic nerves, while from the posterior
angles pass off the two long, oesophageal commissures. These last, befoi’e
reaching the thoracic ganglia, are connected by a transverse commissure.
Upon the thoi’acic succeed numerous abdominal ganglia, those of each pair
of which, as in the fii’st, are wide apart, but they gradually approximate
posteriorly, and at last are fused into a single mass.

The two thoracic ganglia, as well also as the anterior abdominal pairs,

21 Geophilus.

22 Treviranus , Verm. Schrift. II. p. 31, Taf.
VII. fig. 2, 5 ( Lithobius and Geophilus) ; Ku-
torga, be. oit. p. 15, Tab. II. fig. 2, Tab. III. fig.
1, 2 {Scolopendra morsitans ) ; but especially
Newport , Philos. Trans. 1834, p. 40S, PI. XVII.
fig. 43-48 {Scolopendra), and 1843, p. 257, PI. XI.
fig. 11-13 {Geophilus).

23 Newport , loc. cit. 1843, p. 252, PI. XI. fig.
6, 10, or Owen , Lect. &c. p. 200, fig. 99.

24 There are only six pairs of ganglia with
Glomeris ; see Brandt , in Muller's Arch. 1837,
p. 321, Taf. XII. fig. 6. But these ganglia are
very numerous with Julus ; see Treviranus ,

Verm. Schrift. II. p. 16, Taf. IX., and Newport ,
Phil. Trans. 1843, p. 247, PI. XI. fig. 1. The
number of ganglia increases in general with the
increase of the body together with that of the num-
ber of the segments and feet.

25 Van der Hoeven , Recherch. &c. p. 21, PI.
III. fig. 2, 3.

26 This system has been described by Gaede
{fViedemann's Zool. Magaz. I. Stuck 1, p. 91, Taf.
I. fig. 1), and by Berthold (Isis, 1830, p. 690, Taf.
VII. fig. 4). But for the most careful researches
on this subject we are indebted to Zaddach (loc. cit.
p. 35, Tab. in.).

§ 272.

THE CRUSTACEA.

321

are connected together by double, transverse commissures, which, poste-
riorly, become single, and, finally, wholly disappear. The longitudinal
commissures are disposed in a like manner ; they are double and wide
apart in front, hut, posteriorly, approximate and are proportionably short-
ened, until they fuse together, and then entirely disappear, — the cord
terminating in a simple moniliform band which ends above the last pair of
feet. The other abdominal segments which have no feet, receive their
nerves from two long cords which arise from the twenty-fourth and twenty-
fifth abdominal ganglia and accompany the intestinal canal to the last
segment of the tail, where they end in a ganglionic enlargement from
which are given off several short filaments, beside a long nerve to the two
caudal bristles. In the other Phyllopoda, the nervous system is observed
with difficulty, probably from its tenuity; and, as yet, only a single flat-
tened cephalic ganglion has been found. <27) With the very small Lophyro-
poda, these difficulties are even greater, for here there has been observed a
multi-constricted, nervous mass, situated in front of the oesophagus, which
may be regarded as a cerebral ganglion, since it sends off, in front, several
filaments to the tactile and ocular organs ; and behind, two cords which
surround the oesophagus, and join, perhaps, in an abdominal ganglion/281
Among the Siphonostoma, with Argulus, as with the Lophyropoda,
the nervous centre is reduced to a cerebral mass situated above the pro-
boscis,— and composed of three ganglia arranged triangularly/291 With
the other parasitic Crustacea, of which the head and organs of sense have
gradually disappeared, the cerebral ganglion always becomes correspond-
ingly less apparent, while the abdominal cord is the more distinct. This
is so with the genus Chondr acanthus, which has a cerebral ganglion, and in
the few segments of the body, several widely separated (laterally) ganglia
connected together by longitudinal, double commissures/301 With Diche-

27 Brongniart , loc. cit. p. 87, PI. XIII. fig. 2,
3, a. (. Limnadia ), anti Joly, loc. cit. p. 310, PI. Y.
fig. 5, k. and PI. YIII. fig. 21, a. (Isaura). This
last naturalist has been unable to find a cerebral
ganglion with Artemia (loc. cit. p. 242).*

28 An analogous brain, divided by constrictions
into three ganglia placed in a row, has been fig-
ured by Schaffer (Die zackigen Wasserfldhe, loc.

* [ § 272, note 27.] The investigations of Ley-
dig (loc. cit. Siebold and Kolliker's Zeitsch. III.
p. 290) have shown that, with at least Artemia and
Branchipus of the Phyllopoda, the nervous system
is well developed. This system seems, for the most
part, to have escaped the observation of former in-
vestigators from want of manipulation 5 Leydig
has described it with detail, and divides it, as
usual, into a central and a peripheric portion. The
first consists of the brain which sends off nerves to
the organs of sense (eyes, antennae, &c.) and con-
nectSj by two commissural cords which embrace
the cesophagus, with the ventral cord. This cord
is composed of eleven ( Branchipus ), or twelve
( Artemia ) ganglia, which are connected, succes-
sively, by jtwo longitudinal commissures, and, lat-
erally, each, by a double, transverse commissure.
Each of these ganglia sends off, from its outer
border, three nerves which are distributed to the
abdominal organs and appendages, and to the skin.
— Ed.

cit. p. 39, Tab. II. fig. IT. 1, 2, 3), by Straus (loc.
cit. p. 396, PI. XXIX. fig. 6, b. d. e. ( Daphnia )),
and by LovSn (loc. cit. p. 151, Taf. Y. tig. 5, d.
( Evadne )).

29 Jurine , Ann. du Mus. YII. p. 447, PI.
XXVI. fig. 11, and Vogt , loc. cit. p. 14, fig. 1, L.,
lit

30 Rathkt , Nov. Act. Nat. Cur. XX. p. 125.

t [ § 272, note 29.] The recent researches of
Leydig (loc. cit. Siebold and Kolliker's Zeitsch.
II. p. 328) have extended our knowledge of the
nervous system with these lower Crustacea. In
Argulus , this observer found the central nerv-
ous system to consist of a cerebral portion and a
ventral cord. The first, or brain, is composed of
two parts — one anterior and club-shaped, the
other, beneath the first, pyriform and much the
larger. This portion connects, by two commis-
sures which embrace the cesophagus, with the
ventral cord. This cord is composed of six gan-
glia. He observed the following distribution of the
peripheric portion of the nervous system. From
the brain arise the optic nerves, and behind these,
two pairs of nerves for the antennae 5 of the ven-
tral ganglia, the first, third and sixth give off
nerves to the appendages of the body and its
internal organs. Leydig found no trace of a
splanchnic system with these animals. — Ed.

322

THE CRUSTACEA.

§ 273.

lestium, the cerebral ganglion is entirely wanting, but, in its stead, there is
a conspicuous thoracic ganglion under the oesophagus, from which passes off
an equal number of nerves in front and behind, and which is succeeded,
posteriorly, by a large nervous trunk as the abdominal cqrd. This cord
has ganglionic enlargements in the three anterior abdominal segments, and
finally divides into two branches which extend to the very extremity of the
tail. (31) With Achtheres, and Peniculus, the nervous centres consist only
of two trunks lying on the lower surface of the abdomen, each side of the
intestinal canal. (32>

With the Cirripedia, which are headless, the nervous centre consists of
two parallel abdominal trunks, which, in their course, form six to seven
ganglionic enlargements from which pass off, laterally, nerves to the cirri.
The two anterior ganglia are connected by a nerve which stretches arcu-
ately over the oesophagus, and sends filaments to the organs of mastication,
so that a brain proper is wanting. The last two pairs of ganglia are
blended into a single mass, which sends nerves to the cirri, and two fila-
mens into the long tail.(33)

§ 273.

The Vegetative nervous system is distinctly developed with many Crus-
tacea. It consists of a single or of a double Splanchnic nerve.

With the Decapoda, and Squillina, a single splanchnic nerve arises from
the posterior border of the bi’ain, — passes over the stomach, at the same
time enlarging into one or two ganglia, distributes its branches to the walls
of this organ, and, finally, enters the liver right and left.

This nerve is reinforced by two filaments, which, conjointly with the
nerves of the masticatory organs, are given off from the ganglionic enlarge-
ments of the two oesophageal commissures, and, before entering the
splanchnic nerve, send off filaments directly to the lateral walls of the
stomach. a)

With the Oniscidae, there are two splanchnic nerves. On each side of
the small stomach are two ganglia which connect with the brain by a short
filament, and send off, posteriorly, small branches to the walls of the stom-
ach.(2)

With the Myriapoda, there are also two systems of splanchnic nerves.

31 Rathki, Ibid. XIX. p. 150, Tab. XVII. fig.
3, 4.

32 Nordmann , Microgr. Beitr., Hft. 2, p. 72, 109,
Taf. V. fig. 7, J., 6.

33 Cuvier , M£m. loc. cit. p. 11, fig. 11, and
Martin St. Ange , loc. cit. p. 18, PI. II. fig. 8
(Lepas) ; also Wyman in Silliman's Amer. Jour.
XXXIX. 1840, p. 182 ( Otion ).*

1 We are indebted to Brandt for very complete
contributions on the sympathetic system of the
Decapoda *, see his Bemerk. fiber d. Mundmagen-
oder Eingeweidenerven der Evertebr. loc. cit. p. 7,
Tab. I. fig. 1-3 ( Astacus and Squilla ), (also in the
Ann. d. Sc. Nat. V. 1836, p. 87, PI. IV. and in the
Mediz. Zool. II. Taf. XI. fig. 1, i.) ; see, also,

* [ § 272, note 33.) Subsequent researches have
shown that with some at least of the Cirripedia,
there is a proper brain furnishing nerves to the
organs of sense ; see Darwin , Monogr. of the sub-

Krohn , Isis, 1834, p. 529, Taf. XII. fig. 1-4, and
Schlemni , I)e hepate ac bile Crustaceorum et Mol-
luscorum, loc. cit. p. 16, Tab. I. fig. 2, Tab. II. fig. 13
( Astacus Jluviatilis). Suckow (loc. cit. p. 62, Tab.
XI. fig. 7, g.) in the Crawfish, and Newport (Philos.
Trans. 1834, PI. XVII. fig. 40, f.) in the lobster, have
observed only a single splanchnic nerve, which they
have regarded as a cardiac nerve. Audouin and
Milne Edwards, on the other hand, have described
and figured with both the Macrura and the Bra-
chyura, double splanchnic nerves, but the single
one was entirely overlooked.

2 Brandt , Bemerk. &c. p. 14, and Medizin. Zool.
II. p. 75, Taf. XV. fig. 27, c.

class Cirripedia, &c., p. 48 (Lepas). Even in the
description referred to above, of Otion , by Wyman
in Silliman's Jour., a brain is really spoken of. —
Ed.

$$ 274, 275.

THE CRUSTACEA.

323

The single stomato-gastric system consists of two short trunks which
extend from the brain in front, send several small filaments to the parts of
the mouth, and finally pass in front of the brain, — ending in a small gan-
glion. From this last, arises a single nerve, which passes under the brain
and extends along the oesophagus to the stomach, being, in its course,
sometimes enlarged like a ganglion. The double splanchnic system, on the
other hand, is composed of a double row of ganglia accompanying the
oesophagus, and connected, partly by the posterior border of the brain and
the single nerve, and partly by nervous branches. The filaments given off
from these ganglia are distributed not only to the oesophagus, but also to
the salivary glands.®

In the genus Limulus, there is observed, as a single splanchnic nerve,
only one nerve, having a ganglion and situated on the heart ;3 (4) while, with
Apus , the splanchnic nervous system is highly developed. The two
oesophageal commissures furnish, as with the Decapoda, two nerves which,
shortly afhpr their origin, are connected by a transverse commissure. On
the oesophagus, they are blended into a single nerve, and send to this canal
numerous filaments.® With the other inferior Crustacea, no splanchnic
nerves have as yet been observed.

CHAPTER IV.

ORGANS OF SENSE.

§ 274.

The sense of Touch is highly developed with Crustacea. Its seat is in
the multi-articulate antennae, situated on the head, or cephalic extremity,
which always contain large nerves arising directly from the brain. Often,
the masticatory organs have one or several pairs of tactile appendages ; and,
not unfrequently, several pairs of the feet neighboring the mouth, are
changed into tentacular, tactile organs, which play an important part in the
choice and prehension of food.®

§ 275.

As Olfactory organs, with the Crustacea, may undoubtedly be regarded
the two shallow excavations which, with the Macrura, and with Pagurus,
are situated in the basal joint of the two median antennae. Each of these
cavities communicates, externally, by a fissure-like opening, placed on the
upper surface of the joint, and usually fringed with fine bristles. Inter-

3 Brandt , Bemerk. &c. p. 34, Taf. III. fig. 6-9, Julus ; see his Verm. Schrift. II. p. 47, Taf. IV.
and in Muller's Arch. 1837, Taf. XII. fig. 7 g.

( Scolopendra , Spirobolus , and Glomeris) ; also 4 Van der Hoeven; loc. cit. p. 23.

Newport , Philos. Trans. 1843, p. 246, PI. XI. fig. 5 Zaddach , loc. cit. p. 36, Tab. III. fig. 6.

1, 2 (Julus). Trcviranus had already seen 1 The various differences of form of these tactile

something of a single sympathetic system with organs belong rather to Zoology.

324

THE CRUSTACEA.

§ 276.

nally, these organs are lined by a soft membrane, which contains a nerve
arising from the brain in common with the internal antennal nerve. (1)

O

§ 276.

Organs of Hearing, with the Crustacea, have as yet been observed only
with the Decapoda.(1) With these Crustacea, there is a hollow conical pro-
cess, perforated at its obtuse apex, on the lower surface of the basal joint of
the external antennae. Its opening is always closed by a kind of Tympa-
nitic membrane, in the centre of which there is usually a fissure.® Behind
this conical process, and in the cephalothorax, there is a large, thin-walled
sac, filled with a clear liquid; this is prolonged by a kind of neck into the
process, and has, undoubtedly, the function of a Labyrinthus,&) for, a
special nerve, arising from the lateral parts of the brain, in common with
the external antennal nerve, is spread upon its walls.®

The base of this labyrinth is in connection with a singular {glandular
organ, of a usually greenish color, but whose nature is yet undetermined.®

1 These olfactory organs were first described and
considered as such by Rosenthal ( ReiVs Arch. X.
1811, p. 433, Taf. VIII. fig. 1-4) with the craw-fish
and lobster. Treviranus (Biologie, VI. 1822, p.
308) has subsequently confirmed these observations
with the lobster. See, for this same animal, Milne
Edwards , Hist. Nat. d. Crust. PI. XII. fig. 1.
These organs have been found latterly, also, by
Farre , with Palinurus and Pagurus , (Philos.
Trans. 1843, p. 233, PI. IX. X. and Ann. of Nat.
Hist. XII. p. 229). I have myself observed them
with Palaemon , Nephrops , and Mala. It is diffi-
cult to understand how Farre could have taken
these cavities for organs of hearing into which
grains of Sand, entering by accident, would serve
as otolites.

1 Although special auditive organs have not yet
been observed with the other Crustacea, yet it
cannot be denied that they are sensible to sounds.
At least, the observations of Coldstream (Cyclop,
of Anat. I. p. G88) show that the Cirripedia have
a very acute sense of hearing, for they appear
cognizant of the slightest sound, and quickly close
the shell.

2 This cylindrical protuberance, with its tym-
panitic membrane, is easily seen in the basilar ar-
ticle mentioned, with Homarus , Astacus , Ne-
phrops, Palinurus , and other Macrura ; — see
Scarpa, Anatom, disquis. de auditu et olfactu.
p. 2, Tab. IV. fig. 4, a. b. 5 IVeber, De aure animal,
aquatil. p. 8, 106, Tab. I. fig. 1, No. 1, and Milne
Edwards, Hist. Nat. d. Crust. PI. XII. fig. 11, o,
{Astacus). This protuberance is long and cylin-
drical with Pagurus striatus, and Homola Cu-
vieri.

With the Maiina, whose antennal articles are
large and immovable, * the auditive organs are
slightly protuberant, and situated near the mouth.
See Savigny , Descrip, de PEgypte, loc. cit. PI.
VI. fig. 4.2 and 6.2- a. e. ( Mala and Stenorhyn-
■ chus ), and Milne Edwards t loc. cit. I. p. 268. PI.
III. tig. 2, e. PI. XV. fig. 2, 10, 16 {Mala, Mith-
rax, Leucippa, and Camposcia).

With Sc y liar us latus, whose antennae are very
large and fixed at their base, the large but flat
auditive cylinders are very short and near together
on the borders of the mouth {Savigny loc, cit. PI.
VIII. fig. l.a. a. e.). With Scytlarus arctus , I

+ [ § 276, note 2.] The organ of hearing in Leu-
cifer first noticed by Souleyet, has since been
studied by Huxley (Ann. of Nat. Hist. 1851, p.
304) who appears to have clearly made out the
structure which resembles the ordinary form of

have found the same concealed in the semilunar de-
p cessions which are underneath the mouth. With
Mala, these cylinders are obliquely truncated, and
are articulated with the large and basilar articles
of the antennae. They can be depressed towards
the inner side, and then righted as a kind of ex-
ternal auditive conch, and for this purpose the in-
ternal surface of the cylinder has a pair of mus-
cles which are inserted on an internal, stirrup-like
process *, see Cavolini , Abhandl. fiber die Erzeu-
gung d. Fische und der Krebse, p. 133, and Milne
Edwards , Hist. Nat. d. Crust. 1. p. 124, PI. XII.
fig. 10, e. 1. in., and fig. 11, or in Cyclop, of Anat. loc.
cit. p.768, fig. 397, 398. Further researches are nec-
essary, before the opinion of Souleyet {Froriep's
neue Notiz. XXVIII. p. 84) can be admitted, that
a small, round, glittering body which, with Leucifer,
is situated at the base of the internal antennae, is
an auditive organ.*

3 Formerly, the attention had been called only to
the portion of this labyrinth which is concealed in
the auditive cylinder ( Scarpa , loc. cit. Tab. IV.
fig. 6, and Weber, loc. cit. Tab. I. fig. 2). It is
only lately that it has been shown that this small
auditive vesicle belongs to a very large ampulla sit-
uated at its base *, see Brandt, Mediz. Zool. II. p.
64, Taf. XI. fig. 13, a. a., and Neuwyler, Anatom.
Untersuch. fiber den Flusskrebs, in the Verhandl.
d. schweizer. Naturf. Gesellsch. bei ihrer Versam-
mel. zu Zurich, 1841, p. 176.

4 Scarpa, loc. cit. Tab. IV. fig. 5, g. g., and We-
ber, loc. cit. Tab. I. fig. 2, No. 7 5 Brandt, and
Neuwyler , loc. cit. , Farre, Philos. Trans. 1843,
PI. IX. fig. 10, e. e.

5 This glandular body which appears to be pres-
ent with the Brachyura also, is situated, with the
Astacina, behind the base of the external antennae,
concealed in the lower portion of the shell, and
covered, in part, by the membranous labyrinth 5 see
Roesel , loc. cit. p. 322, Tab. LVIII. fig. 9, c.;
Suckow, loc. cit. p. 55, Taf. IX. fig. 2, a.-, Brandt
Mediz. Zool. p. 64, Taf. XI. fig. 8, k. {Astacus),
Milne Edwards, Hist. Nat. d. Crust. PI. XII.
fig. 9, a. 10, g. {Astacus and Mala). Neuwyler
has given the green glands of the craw-fish a spe-
cial examination (loc. cit.). He found that they
consisted of an intestinoid tube communicating
with the membranous labyrinth. At first he

auditory apparatus in the Mollusca. See also
Schodler {Wiegmann’s Arch. 1846, p. 363) upon
this organ with Acanthocercus rigidus ; finally,
Darwin , loc. cit. Cirripedia, p. 53. — Ed.

§ 277.

THE CRUSTACEA.

S25

§ 277.

The sense of Sight is present quite universally with Crustacea. a)

The Cirripedia, the Penellina, and the Lernaeodea, alone, are without it ;
and even here this deficiency occurs only during the last phases of their re-
trograde metamorphosis, when these animals remain fixed to foreign bodies.®

There is, moreover, in the other orders, here and there a genus which
contains blind individuals. Such is the case with the females of certain
parasitic Isopoda,® and with some subterranean Myriapoda.(4)

The eyes of Crustacea present very various grades of development. The
lowest of these is seen in the so-called Simple-eyes. With these, there is
observed a convex cornea, and, behind it, a round, light-refracting body.
This lens is surrounded by a layer of black, brown, red, or blue pigment,
which, at its most convex point, is perforated by an optic nerve. The
young individuals of the Cirripedia, the Penellina, and the Lernaeodea, have
an eye of this kind in the middle of their forehead, but which gradually dis-
appears in the course of their metamorphosis.® Certain Ergasilina, as
likewise the Lophyropoda and Phyllopoda, have, also, at their escape from
the egg, a simple eye, which, with the Ergasilina, and certain Lophyropoda,

thought them comparable to a cochlea, but he was
unable to find any nerve going to them, and has
relinquished this idea, — doubting that these organs,
and the ampulla mentioned, are really auditive or-
gans. Farre (loc. cit.) has gone further 5 he has
taken these bodies for olfactory organs, and has
endeavored to show, as already mentioned, the or-
gans of smell to be real organs of hearing. It is
true that, in the organs of hearing, no otolites are
found •, but the principal parts exist, such as a Ca-
vum tympani. at the entrance of which is extend-
ed a tympanitic membrane and an auditive vesi-
cle, upon which is spread a nerve.

The view of Frey (De Mysidis Anat. p. 13),
then, is inadmissible 5 he regards the seat of hear-
ing, with My sis , as the two internal caudal valves,
where he has observed a cavity containing a radi-
ated body, the nucleus of which has a crystalline
structure, and which he regards as an otolite.
But, aside from the singular structure of this body,
he does not mention its having any special nerves.

It is, moreover, unnecessary to seek, with those
Crustacea whose antennae are highly developed,
the auditive organs anywhere but on the head •,
for, at the base of these antennae, as, for example,
with the Amphipoda, there are several other hol-
low processes which, in part, have been regarded
as palpi, but which, upon more careful examina-
tion, will undoubtedly be found to be, some auditive,
and others olfactory organs.

Frey and Leuckart (Beitr. p. 114, Taf. II. fig.
18) have, from the first, described in more detail
the organs of the caudal valves of My sis, as
proper auditory organs 5 but, aside from the two
so-called otolites which, contrary to all analogy,
are provided with stiff bristles, the correctness of
this interpretation is always open to question, for
these authors have been unable to perceive any

* [§ 277, note 2.] Recent investigations have
disclosed the existence of eyes with the Cirripedia.
Leidij (Proceed. Acad. Sc. Phil. IV. 1848, No. ^dis-
covered them with Balanus , and this discovery has
led to the confident and successful search of them
in other genera. With Lepas , according to Dar-
win (Monograph, &c., loc. cit. p. 49), there are two
closely-approximated eyes, forming a double eye,
28

nerve destined for these so-called auditive capsules,
with My sis.

1 For the eyes of Crustacea, see especially J.
Muiler , Zur vergleich. Physiol, d., Gesichtsinnes,
p. 307 j or its abstract in Ann. d. Sc. Nat. XVII.
1829, p. 225, or his later researches on the eyes of
the Insecta and Crustacea, in MeclceVs Arch.
1829, p. 38, and in Tiedemann's Zeitsch. f. Phys-
iol. IV. p. 97.

2 The adult Cirripedia, notwithstanding the ab-
sence of eyes, are very sensitive to light. This I
have observed with individuals of Balanus pusil-
lus , which I had captive several weeks at Danzig.
These animals, when undisturbed, came out of their
shell, and executed the usual motions of their cirri,
but they withdrew as quick as lightning into the
shell, when, from passing my hand over the vessel,
I shaded them. Coldstream (Cyclop, loc. cit. p.
688) has made similar observations.*

3 The females of Jone, Phryxus , and Bopyrus. t

4 For example, with Polydesmus , Blamulus ,
Cryptops , and Geophilus.

5 For example with Achtheres , Tracheliastes ,
Lernaeocera ( Nordmann , loc. cit. p. 80, &c.,
Tab. IV. fig. 5, Tab. VI. fig. 5, 6). The Cirripe-
dia have, at their escape from the egg, a single,
black eye, according to Thompson ; see the Philos.
Trans. 1835, p. 355, Owen , Lectures, &c., p. 161,
fig. 88 ; and Goodsir , Edinb. new Plnlos. Jour.
1843, No. 69, p. 97, PI. III. fig. 8, and PI. IV. fig.
13-17 {Lepas and Balanus ); but with the embry-
os of Balanus pusillus , I have found this eye of
a red color. The reason why Burmeister (Beitr.
&c. p. 15, Taf. I. fig. 2) could perceive no eye
with the young of Lepas , is, as he himself has re-
marked, because they had been effaced by the
alcohol in which the specimens examined had
long been preserved.

situated at the extremity of two optic nerves which
proceed each from an ophthalmic ganglion. These
ganglia are situated on two nervous cords which
arise from the supra oesophageal ganglia. — Ed.

t [ § 277, note 3.] Quite remarkable among the
blind Crustacea is the Astacus pellucidus Telk.
from the Mammoth Cave, Kentucky. — Ed.

326

THE CRUSTACEA.

§ 277.

remains as a visual organ during the whole life ;(6) while, with other Lophy-
ropoda, and with the Phyllopoda, it either entirely disappears, (7> or remains
in a condition apparently rudimentary, by the side of the other eyes, which
are subsequently formed.® With certain Ergasilina,® and some Lophy-
ropoda,<10) with the Caligina,(11) and the males of some parasitic Isopoda,(12>
there are two permanent eyes, right and left, on the vertex of the head.
The Poecilopoda, also, have, beside their compound eyes, two simple ones,
contiguous on the middle of the forehead. (13) These simple eyes are also some-
times the more numerous, and are then situated on each side of the head,
in fours, sixes or eights, in a single or double row, constituting the Oculi
seriati , as is observed with some Myriapoda; (U) or they are collected in a
thick group of twenty to forty, constituting the Oculi gregati, as is the case
with other Myriapoda, and with the Isopoda.<13) Each of these eyes has a
separate branch of the optic nerve ; this nerve, therefore, divides as many
times as there are eyes.

Another form of eyes which is pretty common among Crustacea, but
which has many modifications, has received the name of Compound Un-
faceted Eyes.

These organs are composed of a common cornea, covering numerous
simple eyes, closely set against each other. They are found in their Sim-
plest form, with the Cirripedia at a certain epoch of development, with
the Argulina, the Laemodipoda, and certain Lophyropoda, Phyllopoda
and Amphipoda. Here, directly under the cornea, are a greater or less

6 Lamproglena , Ergasilus ( Nordmann , loc.
cit. Tab. II. fig. 1, 7), Cyclops , Cyclopsina , Cy-
pris, &c.

7 With Limnadia , and Isaura , it is replaced by
a compound eye ; see Joly, Ann. d. Sc. Nat. XVII.
PI. IX. fig. 39-41.

3 This is so with the adult individuals of Apus
and the Branchiopoda, where the simple embryonic
eye persists in an atrophied condition between the
two faceted eyes ; see Schaffer , Der krebsartige
Kiefenfuss, Taf. II. fig. 1 c., and Taf. V. fig. 3-5 ;
also, Zaddach , loc. cit. p. 48, Tab. II. fig. 18-22, C.
and Tab. IV. (Apus); Prevost , in Jurine's Hist,
d. Monocles, PI. XX.-XXI. ( Chirocephalus ), and
Joly , loc. cit. XIII. PI. VII. ( Artemia ). The
black spot observed front of the compound eye,
with Lynceus , and certain species of Daphnia , is
certainly only the remains of the simple eye ; see
Muller , Entomostr. Tab. IX.-XI., and Jurine ,
Hist. d. Monocles, PI. XV.-XVI.

But, with this simple rudimentary eye, should
not be confounded the problematical vesiculiform
organ which is found behind the compound eyes of
certain Phyllopoda and Lophyropoda. With Apus ,
this organ contains a nucleus, divided into four
parts (Schaffer, loc. cit. Taf. II. fig. 1, b., or Zad-
dach, loc. cit. p. 48, Taf. II. fig. 10. P., 25).
The vesiculiform body which, with Limnadia ,
stretches from the inner surface of the head, be-
hind the eye, towards the forehead (Brongniart,
loc. cit. p. 83, PI. XIII. fig. 6), may serve, accord-
ing to Straus , to fix the animal to foreign bodies j
(see Mus. Senckenb. II. p. 126, or Firussac, Bull.

* [ § 277, note 8.] With Artemia and Branchi-
pus, Leydig (loc. cit. Siebold and Kolliker's
Zeitsch. III. p. 295) has foQnd very highly-devel-
oped eyes. In structure they correspond to the
compound faceted eyes described below. In re-
gard to the pigment-spots found on the head of
these animals, and regarded as of a visual charac-
ter by Joly and others, this observer considers

d. Sc. Nat. XXII. 1830, p. 333). With Evadne ,
there is found at the same place, behind the large
eye, a circular muscle, which also, perhaps, is for
the attachment of the animal.*

9 Nicothoe ( Rathki , Nov. Act. Nat. Cur. XX. p.
102, Tab. V. fig. 1,8, 10).

10 Hersilia , Peltidium , &c. (Philippi, in Wieg-
mann's Arch. 1839, I. p. 128, Taf. IV. fig. 9, 13,
or Milne Edwards, Hist. d. Crust. PI. XXXVII.).

11 Pandarus, Caligus, Trebius , Dinematura,
&c. (Milne Edwards, Hist. d. Crust. PI.
XXXVIII., and Kroyer, in the Naturhist. Tidskr.
I., or in the Isis, 1841, p. 188, Taf. I.).

12 Phryxus and Bopyrus (Rathki, Nov. Act.
Nat. Cur. XX. p. 44, Tab. I. fig. 13, in Tab. II. fig.
3, and, De Bopyro et Nereide, Tab. I. fig. 2).

13 See Van der Hoeven, Recherches, &c., 23,
PI. III. fig. 5, a. a., 6, C.

14 With Platyulus , there are, on each side, six
eyes, arranged in two rows. Scolopendra has
four, while with Glomeris , there are eight, which
form a simple arcuate row on each side ; see Mul-
ler, in MeckeVs Arch. 1829, p. 40, Tab. III. fig.
3, 4, also Kutorga, loc. cit. p. 17, Tab. III. fig. 3,
4 (Scolopendra), and Brandt, Mediz. Zool. II.
p. 99, Taf. XV. fig. 43 (Glomeris).

1-5 Treviranus , Vermisch. Schrift. II. p. 32,
Taf. VII. fig. 1 (Lithobius) and Muller , in Meck-
eVs Arch. 1829, p. 43 (Julus) ; see also Trevi-
ranus loc. cit. I. p. 64, Taf. IX. fig. 54 (Porcellio),
Muller, loc. cit. p. 42, Taf. III. fig. 5, 6 (Cymo-
thoa), and Lereboullet, Ann. d. Sc. Nat. loc. cit.
p. 107, PI. IV. fig. 2, 2b> (Lygidium).

them as mere accumulations of pigment granules,
having no special function whatever. This natu-
ralist alludes, also, to the problematical body above
mentioned. He did not observe it with Artemia,
but it was present with Branchipus, and larger in
the larval than in the adult conditions. He hesi-
tates to express an opinion as to its nature. — Ed.

§ 277.

THE CRUSTACEA.

327

number of round, pyriform, or cuneiform lenses, the pointed posterior
extremity of which is surrounded by a pigment matter of usually a deep
brown or black color, while the rounded anterior extremity is always
widely protuberant. The optic nerve, before reaching this pigment, divides
into as many branches as there are lenses.

With Argulus ,(16) Cyamus,m and with the Amphipoda/18' there are always
two considerably flattened eyes ; while with Daphnia , Lynceus , Polyphemus ,
Evadne,m (the Lophyropoda) and also with the young bivalve Cirripedia,(20)
there is, on the other hand, only a single ocular bulb, spheroidal, and the result
of the fusion of two eyes ; it receives, therefore, the two optic nerves which are
separated from each other by the median line of the body. With Limnadia ,
and Artemia, of the Phyllopoda, this fusion is less complete, for, upon close
examination, the line of separation may be seen.(21) With many Daphnioi'dae,
this cyclopean eye has several muscles, corresponding to the recti muscles of
the Vertebrata, which give the eye a movement of rotation about its centre. (22)

With some Crustacea belonging to the orders Amphipoda, Phyllopoda,
and Poecilopoda, the compound eyes are so modified, that, beneath the
cornea which is simple, there is another cornea that is faceted. Each of
these facets consists of a depression, in which fits the truncated extremity
of an oblong, conical lens ; and the opposite extremity of this lens is sur-
rounded by pigments, and connected with a filament of the optic nerve. (23)

A second modification of these compound e}7es is also observed with some
Amphipoda and Phyllopoda. Here, the cornea is likewise double, but be-
tween the faceted one and the conical lenses, are interposed peculiar lenses
of an oval form.(24>

The third form of eyes observed with Crustacea has received the name
of Compound Faceted Eyes. These are found in the genus Scutigera,
and in the higher groups of Crustacea, namely : the rftomapoda, and
Decapoda, with which the eyes are situated at the extremity of two peduncles,
or, what is more rare, at a point below their extremity/25' These peduncles
are movably inserted on the anterior border of the cephalothorax, and are

16 Jurine , loc. cit. p. 446, PI. XXVI. fig. 13,
and MiiLLer , in Tiedemann's Zeitsch. f. Physiol.
IV. p. 97, Taf. VI. fig. 5, 6 (Argulus folia-
ceus ).*

17 Roussel de Vauztme , loc. cit. p. 242, PI.
VIII. fig. 5.

16 Muller , in MeckeVs Arch. loc. cit. p. 57, Taf.
III. fig. 16, 17 ( Ganimarus ).

19 The lenses are pyriform with Daphnia ( Straus ,
loc. cit. p. 397, PI. XXIX. fig. 6, 7), cuneiform with
Polyphemus and Evadne (Jurine, Hist. d. Mon-
ocles, PI. XY. fig. 1-3, and Lovin, loc. cit. p. 148,
PI. V.).

20 it is very remarkable that the Cirripedia, af-
ter the disappearance of the simple eye, which,
during the embryonic state, is situated on the front,
acquire another, compound but equally transitory.
This last is situated at the lower border of the ce-
phalic extremity, directly in front of the mouth, dur-
ing the period when these animals are contained
between two shells, and swim like a Cypris. It
is pedunculated, and has the same structure as
that of Daphnia ; see Thompson, Zool. Research.

* f § 277, note 16.] For the intimate structure
with many details, of the eyes of Argulus , see Ley-
dig (loc. cit. Siebold and Kolliker's Zeitsch. II.
p. 331, Taf. XX . fig. 1) ; they are not immovable
aB Jurine has described. — Ed.

loc. cit. p. 77, PI. IX. fig. 3, 4 5 and Burmeister ,
Beitr. p. 17, Taf. I. fig. 3-5.

21 See Brongniart , loc. cit. p. 85, PI. XIII. fig.
3, 4 (Limnadia), and Joly loc. cit. p. 309, PI. VII.
fig. 3, PI. VIII. fig. 24, 26 (Isaura). In this last-
mentioned Crustacean the eyes contain ovoid lenses.

22 Daphnia and Evadne ; see Jurine and Lo-
ven , loc. cit.

23 This modification is found with Arnphithot,
Apus, and Limulus ; see Milne Edwards , Hist,
d. Crust. I. p. 116 *, Z,addach , loc. cit. p. 45, Tab.

II. fig. 18-24, and Van der Uneven, loc. cit. p. 23,
Taf. III. fig. 6, A. B.

24 Hyperia (Milne Edwards. Hist. d. Crust.

III. p. 74, and Ann. d. Sc. Nat. XX. 1830, p. 388,
and Muller , in his Arch. 1836, p. 102), and
Branchipus ( Burmeister , in Muller's Arch.
1835, p. 529, Taf. XIII. fig. 1-4).

The lenses of this last-mentioned Phyllopod are
situated in the cap-like cavities of the cones, so that
this kind of eyes which, moreover, are pedunculated,
form the transition to the faceted ones.*

25 With some species of Ocypoda.

* [ § 277, note 24.] The peculiarity in the struc-
ture of the eye of Branchipus, as above mention-
ed by Burmeister, Leydig (loc. cit. Siebold and
K dlliker's Zeitsch. III. p. 295), was unable to
verify with Branchipus stagnalis — Ed.

t

328 THE CRUSTACEA. § 278.

usually concealed in special fossae. The tetragonal or hexagonal facets of
the cornea are always very numerous ; (2G) — behind each of them, is a con-
ical, or prismatic lens, the round extremity of which is fitted into a trans-
parent conical fossa, corresponding to a vitreous body ; while the conical
extremity of these bodies is received into a kind of calyx, formed by the
filaments of the optic nerve. Each of these filaments, together with its
calyx, is surrounded by pigment matter in a sheath-like manner. (27> *

CHAPTER Y.

DIGESTIVE APPARATUS.

§ 278.

The opening of the digestive apparatus with the Crustacea is usually
situated directly in front of the first pair of feet, which, as foot-jaws, grasp-
ing or prehensile organs, are used for the seizing, the tasting, and the
bearing to the mouth of food.® With many species, there are, as auxil-
iary organs for this purpose, the oar-like, the post-abdominal, and branchial
feet, the movements of which not only produce currents of water necessary
for respiration, but also direct towards the mouth a great quantity of nutri-
tive matter.®

The mouth is generally situated underneath and somewhat removed from
the anterior border of the head. It is covered with a soft upper lip,

26 The facets are tetragonal with Astacus , Ho-
marus, Palinurus , Galathea , Scyllarus , Palae-
7/ion, Pasiphaea , and Penaeus ; hexagonal with
Scutigera , Squilla, Phyllosoma , Pagurus , Cali-
anassa , Ma'ia , Campilius , Portunus , and Ilia ;
see Milne Edwards , Hist, de Crust. I. p. 117, PI.
XII. and Will, Beitr. z. Anat. der zusaramengeset.
Augen, &c., p. 7. fig. 3, c.

27 Will, loc. cit. p. 12, fig. 3, 4 ; see also Suck-
ow , loc. cit. Taf. X. fig. 19, 20 •, Soemmering, De
oculor. sect, horizont. p. 75, Tab. III., and Milne
Edwards , Hist d. Crust. PI. XII. fig. 8 (Astacus).

1 See above, § 268.

2 These acts may be distinctly seen with the

* [ § 277, end.] There is another form of eye
observed by Dana (Report on Crust, loc. cit. p.
1026) with Corycaeus and Sapphirina , and of so
remarkable a character that'l quote his description :
u A pair of simple eyes, consisting of an internal
prolate lens, situated at the extremity of a vermi-
form mass of pigment, and of a large, oblate, lens-
shaped cornea. The cornea is connected intimately
with the exterior shell of the front or the under
side of the head, and the two corneae are like spec-
tacles adapted to the near sighted lensea within *,
their size is extraordinary, being often one-third

Phyllopoda, the Lophyropoda, and the Cirripedia.
These last use principally their long, posterior,
cirrus-like feet, which they unroll and roll up
alternately, maintaining regular currents in the
water. During these movements, the three pairs
of anterior and shorter feet seize, with much ad-
dress, the particles of food borne against them by
the current. Often the oar -like feet with the Daph-
nioidae become dirty in this act, and are glued to-
gether by particles of food which have been ejected
from the mouth. But these animals easily relieve
themselves by curving in front their spinous tail
and combing out the oar-like feet, which are them-
selves ciliated and bristled.

of the greatest breadth of the body in Corycaeus.
The lens and the cornea are often very distant from
each other, being separated by a long clear space.
The external surface of the cornea is spherical j
but the inner is conoideo-spherical, or parabolic.
The texture is firm, and when dissected it breaks
or cuts like a crystalline lens. The true lens is
always prolate, with a regular contour, excepting
behind, where it is partly penetrated by the pig-
ment. The pigment is slender, vermiform, of a deep
color, either red or blue, but at its anterior extremity
usually lighter, and often orange or yellow.1* — Ed.

$ 278.

THE CRUSTACEA.

329

beneath which is a pair of strong upper jaws (Mandibulae), which move
laterally hy means of large muscles arising from the internal surface of the
cephalic and dorsal parts of the skeleton ; the internal border of these
jaws is hard and often denticulated. With the higher Crustacea, these
mandibles have a tactile organ (Palpus).® Behind these mandibles are
two pairs of lower jaws (Maxillae), which are weaker, softer, and deficient in
palpi. They are composed of several pieces, except with the Myriapoda,
where they are fused into a kind of lower lip. Between the two mandi-
bles and the first pair of maxillae, there is a soft, tongue-shaped, and some-
times bifid process, which, also, may be regarded as an under-lip. <4)

With many of the lower Crustacea, the parts about the mouth are vari-
ously modified, whereby they lose their peculiarities as masticatory organs.
Thus with the Poecilopoda, the mouth is simple, infundibuliform, and jaw-
less, — the mandibles and maxillae being changed into cheliform legs.®

With the parasitic Crustacea, the organs of the mouth are changed into
parts for Suction. The two lips are prolonged into a kind of proboscis,
and the masticatory organs become more and more indistinct and finally
disappear entirely. This is best observed with the Caligina where the
mouth has the form of a beak pointing backwards, and the upper and lower
lips are joined together forming a long tube which contains the two very
long, horny, denticulated mandibles, while at its base are two palpiform,
rudimentary maxillae.® With Ar gains, the oral parts form a suctorial
apparatus even more complete. This is a very long proboscis, pointing
forwards, and out of which the two mandibles project in the form of two
small pointed stylets, while the maxillae are entirely wanting.® . With the
Lernaeodea, and Penellina, on the other hand, the proboscis is short, and
contains two short mandibles, which are denticulated and hooked ; and on
its outside are two palpiform, rudimentary maxillae.® But the oral parts
are most abortive with the Ergasilina and Bopyrina. Here, the upper aud
under lips are blended together into a short proboscis without mandibles,

3 With the Decapoda, Stomapoda, Amphipoda,
and the majority of Isopoda. With the Chilopoda,
these palpi exist only in a very rudimentary con-
dition ; and they are entirely wanting with Idothea,
the Chilognatha, and the other lower Crustacea.
For the parts of the mouth of Crustacea, see the
descriptions and figures contained in the works of
Savigny , Milne Edwards , and Erickson ; also
the various monographic works upon the Deca-
poda, Isopoda, Myriapoda, Phyllopoda, Lophyro-
poda, and Cirripedia, by Suckow, Brandt , RathJce ,
Treviranuss, Zaddach, Jurine, Loven , Burmeis-
ter, Martin St. Ange , &c.

4 Astacus , Palaemon , Palinurus , Squilla.

»v

* [ § 278, note 7.] According to Dana , the pro-
boscis here mentioned is simply a spicula without
any mouth-opening or mandibular appendages ;
the true mouth is posterior to this and has a trunk-
form, with the buccal orifice on the under surface,
as in some genera of the Caligoidea, and provided
with regular mandibles ; see Amer. Jour, of Sc.
1837, XXXI. p. 299, also Rep. on Crust, loc. cit.
p. 1322. This has since been verified by Vogt
(Beitmge, &c., p. 7), and by Leydig (loc. cit. Sie-
bold and Kolliker^s Zeitsch. II. p. 332, Taf. XIX.

28*

5 See Van der Hoeven , loc. cit. p. 16, PI. II. fig.
1, A. ( Limulus ).

6 Milne Edwards , Sur ^organisation de la
bouche chez les Crustac^s suceurs, in the Ann. d.
Sc. Nat. XXVIII. 1833, p. 78, PI. VIII. ; and espe-
cially Burmeister , in the Nov. Act. Nat. Cur.
XVII. p. 278, Tab. XXIII.-XXV.

7 Jurine, loc. cit. p. 440, PI. XXVI. fig. 3-7,
16 ; Vogt , loc. cit. p. 7, fig. 5.*

8 Nordmann , Microgr. Beitr. loc. cit. Taf. V.-
IX., and Kollar , loc. cit. Taf. IX. X. ( Adheres ,
Branchiella , C/iondracanthus, Tracheliastes ,
aud Basanistes) ; also Burmeister , loc. cit. p.
310, Tab. XXIV. A. {Lernaeocera).

fig. 2. b.). This last-mentioned author thinks that
the spicula in question is a poison weapon 5 a view
which is rendered probable from the fact that it has
glands connected with it, as in the stings of in-
sects, which glands have hitherto been considered
salivary ; but they do not open into the mouth like
ordinary salivary glands. Moreover, Leydig
quotes the observation of Jurine that tadpoles
pierced by this organ of Argulus , seemed poisoned
and soon died. — Ed.

380 THE CRUSTACEA. * § 279.

and the palpiform maxillae, with only a few exceptions, are wholly want-
ing.®

§ 279.

The Intestinal Canal with nearly all the Crustacea, traverses the body
without convolutions on the median line,a> and the anus is situated at the
extremity of the tail.® Its walls are composed of three to four different
layers, of which the outer, answering to a peritoneal envelope, consists of a
dense fibrous membrane.

The internal layer consists of a structureless, transparent epithelium,
always non-ciliated. Iu the anterior portion of the intestine, which is
often dilated into a kind of stomach, as also in the rectum, this epithelium
is quite dense and is directly continuous with the external skin, and like
it also, contains chitine ; it is moreover, cast off, at the moulting, with
the skin to which it remains attached, partly by the mouth, and partly by
the anus.® Between this epithelium and the peritoneal envelope, there is
a granulo-vesicular, mucous layer, surrounded by smooth, simple, and in-
terlaced, muscular fibres.

With the higher Crustacea, alone, the digestive canal consists always of
a very short oesophagus, a stomach, an intestine and rectum. With the
lower Crustacea, it is only a simple tube of the same calibre throughout,
except near the anus where it is sometimes constricted by the accession of
a muscular layer. With the Siphonostoma,* and many of the Lophyro-
poda and Phyllopoda, it is straight throughout ; <4) but with the Daph-

9 Nordmann , loc. cit. Taf. I. -III. ( Lamproglena
and Ergasilus) ; Rathki, De Bopyro &c. p. 4,
Tab. I. and Nov. Act. Nat. Cur. XX. p. 42, 103,
Tab. II. V. ( Nicothoe and Phryxus ) ; also
Krdyer , Isis, 1841, p. 343, Taf. Y. fig. 7. c. ( Nico -
tho'e ). There is an exception in this respect with
Dichelestium. Its proboscis is prolonged into a
kind of beak surrounded by numerous movable
processes, of which one pair of denticulated stylets
concealed iu a fold of the proboscis corresponds per-
haps to mandibles, while another pair may per-
haps be regarded as maxillae 5 see RatklU Nov.
Act. Nat. Cur. XIX. p. 136, Tab. XVII. fig. 12-
14, and Milne Edwards , Hist. d. Crust. PI.
XXXIX. fig. 4, a-c. or Cyclop, of Anat. loc. cit.
p. 773, fig. 412-415.

1 Glomeris and Lynceus form here an excep-
tion. With the first, the intestine has one curve in
front and another behind ( Brandt , in Muller’s

* [ § 279. J The alimentary canal of the Cali-
goidea, according to Dana (Report. Crust, loc. cit.
p. 1337), is divided into four very distinct parts,— an
oesophagus, small and slender ; a stomach broad
and heart-shaped ; an intestine, marked by light
constrictions, and a rectum provided with power-
ful muscles. The oesophagus has a valve at its
entrance into the stomach, and thereby regurgita-
tion of the food is prevented.

See, also, for the digestive canal of Argulus ,
with its histology, Ley dig (loc. cit. Siebold and
Kolliker’s Zeitsch. II. p. 332, Taf. XIX. fig. 2).
— Ed.

t [ § 279, note 4.] For details upon the struc-
ture of the digestive canal of Artemia and Bran-
chipus , see Leydig (loc. cit. Siebold and Kblli-

Arch. 1837, p. 322, Taf. XII. fig. 2) ; with Lyn-
ceus., it has one or two spiral turns ( Muller , En-
tomostr. Tab. IX. X., and J urine , Hist. d. Mono-
cles PI. XV. XVI.).

2 The Cirripedia form an exception to this rule •,
their anus is situated between the last pair of cirri
and the base of the tail 5 see Cuvier , Mem. loc. cit.
fig. 7, k., and Martin St. Ange , loc. cit. PI. II. fig.
4, 5, &c., h.

3 See Schmidt , Zur vergleich. Physiol, p. 30.

4 For the straight intestine of the Penellina,
Lernaeodea, and Ergasilina, see Nordmann , loc.
cit. Taf. I.-X., also Burmeister , Nov. Act. Nat.
Cur. XVII. p. 311, Tab. XXIV. A. fig. 1. (. her -
naeocera) Rathkt ?, Ibid. XIX. p. 156, Tab.
XVIL. fig. 2 (Dichelestium) ,• Jurine Ilist. d.
Monocl. PI. I.-VII. (Cyclops and Cyclopsina) ;
Prevost , Ibid. PI. XX.-XXII. (Chirocephalus) ;
Joly , loc. cit. PI. VII. VIII. (Artemia). \

ker's Zeitsch. III. p. 283). This observer divides it
into three distinct portions : (Esophagus, Stomach,
and Intestine. The stomach is'composed histologi-
cally of four tunics 5 1. A Muscular, made up of
circular and longitudinal muscles ; 2. A Homoge-
neous, serving as a support for this organ ; 3. A
Cellular 5 and lastly 4, A Homogeneous, which ap-
pears to be merely a continuation in words of the
external Chitine layer. The intimate structure of
the intestine is quite the same as that of the stom-
ach, but the elementary particles of the muscles
composing its muscular tunic, are spindle-shaped,
giving this tissue here a structure quite peculiar,
and unlike anything found elsewhere 5 see loc. cit.
Taf. VIII. fig. 6, 10. — Ed.

§ 279.

THE CRUSTACEA.

331

nioi'lae, and Apodidae, on the contrary, its anterior extremity mounts
towards the dorsal surface of the head, and then curves backwards to the
mouth.®

With the other Crustacea, there is, more or less distant from the oesophagus,
a stomach, formed by a pyloric constriction of the intestine. This stomach
is small with the Cirripedia, Laemodipoda, Isopoda, and Amphipoda ; (6)
but is jjretty long with the Myriapoda.(7> In many of the Isopoda and
Laemodipoda, the stomachic epithelium has stiff’ cilia, or presents a carti-
laginous, or horny aspect, thus constituting a stomachic support and dental
apparatus,® which is also observed in the somewhat larger stomach of the
Poecilopoda and Stomapoda.® But this structure of the stomach is most
prominent with the Decapoda. 'Remarkable for its size and form, it con-
sists of two portions; one, anterior, vesiculiform, communicating with the
oesophagus, the other pyloric, pyramidal, and with the apex pointing back-
wards. The internal tunic of the stomach is composed of chitine and
covered with stiff bristles, or sometimes with groups of very singular hairs
of a forficulate form. Moreover, its callous and cartilaginous portions
form, in the pyloric region, a remarkable support, on which are three solid
movable pieces. One of these pieces is a single tooth placed in the middle
of the posterior wall of the stomach ; while the other two, longer and
somewhat crenulated, are situated on the sides opposite each other. Seve-
ral muscles, arising from the internal surface of the cephalothorax, are in-
serted on this stomach, and it is very probable that, by these, the animal
can voluntarily bring the three pieces together, making them serve as inter-
nal masticatory organs. (1U)

5 For the arcuate intestine of Daphnia , Lyn-
ceus , and Polyphemus, see the figures given by
Jurine , Hist. d. Monocl. j Straus , loc. cit. PI.
XXIX. {Daphnia) ; Brongniart , loc. cit. PI.
XIII. ( Limnadia ) ; Straus, Mus. Senckenb. loc.
cit. p. 112, Taf. VII. fig. 12, and Johy, loc. cit. PI.

VII. fig. 5 ( Isaura ). With Cypris, there is a kind
of stomach on the curved digestive canal ( Straus ,
loc. cit. p. 50, PI. I. fig. 10).

0 For the intestine and stomach of the Cirripe-
dia, see the writings of Cuvier , Burmeister , and
Martin St. Ange ; also Roussel de Vauzime , loc.
cit. PI. VIII. fig. 12, 18 {Cyamus); Brandt,
Media. Zool. II. Tab. XV. tig. 39 ( Oniscus ) ; Lere-
boullet , loc. cit. p. 126, PI. V. fig. 25 ( Lygidium ),
and Rathkd, loc. cit. Taf. IV. fig. 19 ( Idothea ).

1 See Raindohr , Abhandl. iib. d. Verdauungsw.
d. Insek. p. 148, Taf. XV. fig. 1 *, Treviranus,
Verm. Schrift. II. p. 23, 43, Taf. V. fig. 4, Taf.

VIII. fig: 6 ( Lithobius and Julus) ; L. Dufour,
loo. cit. p. 84, 95, PI. V. fig. 1, 4 ( Lithobius and
Scutigera) ; Kutorga, loc. cit. p. 5, Tab. I. fig. 2
( Scolopcndra ) ; and Brandt, in Muller's Arch,
loc. cit. Taf. XII. fig. 2 ( Glomeris ).*

8 The stomach of Oniscus contains a cartilagi-
nous support of a peculiar form ( Brandt , Media.
Zool. II. p. 74, Taf. XV. fig. 41, 42). That of the
stomach of Idothea entomon is composed of seve-
ral solid pieces {Ratlilci, loc. cit. p. 119, Taf. IV.
fig. 20, 21). With Lygidium , the epithelium is
supported by several horny pieces, and provided
with numerous stiff bristles {Lereboullet, loc. cit.
p. 127, PI. V. fig. 26-30). Finally, with Cyamus ,

* [ § 279, note 7.] For the alimentary canal of
Julus in all its details, see Ltidy , A Flora and

there are in the cardiac region of the stomach two
lateral horny tridentate folds ( Roussel de Vauzime ,
loc. cit. p. 251, PI. VIII. fig. 13, 14).

9 With Limulus, the oesophagus extends in
front and opens into a very muscular baokwardly-
curved stomach the epithelium of which has fifteen
longitudinal rows of horny teeth ( Van der Hoeven,
loc. cit. p. 17, PI. II. fig. 3. B.). With Squilla,
the stomach is pyramidal, and has, at its pyloric
region, horny plates and very regular rows of hairs
{Duvernoy, in Cuvier's LeQons d’Anat. Comp.
V. p. 231). With Mysis, also, the epithelium of
the pyriform stomach is supported by several solid
lamellae composed of chitine and covered with
bristles mixed with hairs {Frey, loc. cit. p. 16).

10 The stomach of the Crawfish is the one best
known ; see the descriptions and figures given by
Roesel , Suckow, Brandt, loc. cit., and Milne Ed-
wards, Ilist. d. Crust. I. p. 67, PI. IV. The inti-
mate structure of this stomach and its internal
appendages have been carefully studied by Valen-
tin (Repertorium, I. p. 115, Taf. I. fig. 15-21) and
by Oesterlcn {Muller's Arch. 1840, p. 387, Taf.
XII.).

The teeth and bristles here observed, are found
also with the three divisions of the Decapoda. I
have seen them with Homarus , Palinurus, Gala-
thea, Pagurus, Cancer , Mala, Lupea , &c.
With Crangon, and Palaemon, I found the dental
lamellae wanting but the epithelium was hairy.
With Caridina, according to Joly (loc. cit. p. 73,
PI. III. fig. 27), hairs of this kind are inserted on
the band-like condensations of the stomach.

Fauna within living Animals, in Smithsonian Con-
tributions to Knowledge, V. 1853. — Ed.

332

THE CRUSTACEA.

§ 280.

§ 280.

A large portion of the Crustacea have glandular appendages to the
digestive canal. But it is only a few of these organs to which can be at-
tributed the function of Salivary Glands. Two such of a lobular form,
are found in the Cirripedia on the stomach, and pour their secretion into
the anterior part of this organ.11'

But with the Myriapoda, these organs are very distinct. There are
two or more on each side of the oesophagus and stomach, and their rather
long, excretory ducts open into the oral cavity. t2) With all the other
Crustacea, these organs are wholly wanting.*

The Liver, which exists sometimes as a glandular layer enveloping the
digestive canal, and sometimes as a separate organ, is composed of green-
ish, or of yellowish-brown tubes of variable size, the walls of which are
formed by numerous granular cells, between which are interposed fat-vesi-
cles. <3) With most of the lower Crustacea, with the Siphonostoma, the
Lophyropoda, the Phyllopoda, and Myriapoda, the liver is not isolated
from the digestive tube, but the follicles of its glandular layer are some-
what protuberant on the external surface of this tube, and open on its in-
ternal surface, each probably by a separate orifice. (4) With Argulus,

1 See Cuvier , M£m. loc. cit. p. 10, fig. 9, u. u.,
11. d. (Lepas) ; Burmeister , loc. cit. p. 42, Tab.
II. fig. 13, 14, c. (Coronula) ; Karsten , Nov. Act.
Nat. Cur. XXI. Tab. XX. fig. 1, cl. ( Balanus ).

2 With Lithobius , and Scutigera , there are
two compact salivary glands which extend from
the head into the first segments of the body ( L .
Dufour , loc. cit. p. 83, 95, PI. I. V.). Trevi -
ranus (Verm. Schrift. II. p. 25, Taf. V. fig. 4, q. q.)
regarded them as a mass of fat. The botryoidal
glands, which open by several excretory ducts into
the oral cavity, have been observed by Gaede
( Wiedemann's zool. Mag. I. p. 107, Taf. I. fig. 7, i
i.), by Muller (Isis, 1829, Taf. II. fig. 5), and by Ku-
torga (loc. cit. p. 4, Tab. 1. fig. 4), in the anterior
extremity of the body of Scolopendra. With
Glomeris , there are only two short, slightly fiex-
uous glandular tubes situated in the lower portion
of the head and opening into the mouth ( Brandt ,
in Muller's Arch. 1837, p. 323, Taf. XII. fig. 3).
With other Myriapoda, these organs quite resemble
those of the Insecta. Thus, with Geophilus , there
are two flexuous tubes situated pretty far behind the
head, and from which pass off two very long, small
excretory ducts along the oesophagus to the
mouth ( Treviranus , loc. cit. p. 37, Taf. VII. fig.

* [ § 280, note 2.] For the salivary glands of
Julus see Leidy (A Flora and Fauna within Living
Animals, p. 17, PI. VII. fig. 21, a. b. In Smithson-
ian Contributions to Knowledge, V. 1853). Beside
the long tubular glands mentioned by the authors
above, he has described two others which are
placed on each side of the oesophagus and are
pyriform, conglomerate, and cellular in structure.

Wright (Ann. Nat. Hist. 1848, p. 140) has also
made observations on the glands of Geophilus
which open into the head ; he has shown them to
be veneniferous, for a single excretory duct passes
off from the anterior part of this gland and termi-

3). With Julus , the salivary organs are even
longer and form, with the urinary canals, a very
complicated net-work about the stomach, and from
which pass off, according to Treviranus (loc. cit.
p. 44, Taf. VIII. fig. 6), three excretory ducts to
the mouth. But Ramdohr (Abhandl. &c. p. 149,
Taf. XV. fig. 1, g. g.) has figured only two simple
salivary canals with Julus , and this number has
been verified by Burmeister (Isis, 1834, p. 136).
I have seen these two canals with Julus sabulosus
anastomose in an arcuate manner at their posterior
extremity.*

3 For the intimate structure of the biliary tubes,
see Schlemm , De hepate ac bile Crust., loc. cit. p.
14, Tab. II. fig. 1-8 ( Astacus ), and Karsten,
Nov. Act. Nat. Cur. XXI. p. 295, Tab. XVIII.
-XX. ( Oniscus , Astacus, and Balanus).

4 An hepatic layer of this kind may be observed
with the Penellina, Lernaeodea, Ergasilina ( Nord -
mann , loc. cit. Taf. I.-X.), and with Artemia ( Joly ,
loc. cit. p. 239, PI. VIII. fig. 4). The numerous
caeca, which, according to Rathkt (Nov. Act. Nat.
Cur. XX. p. 122, Tab. V. fig. 15), belong to the
entire digestive canal of Chondr acanthus, are
perhaps formed by an hepatic substance. With
the Chiloguatha, and Chilopoda, I have found the

nates, on each side, in a canal of the jaw or mandi-
ble, as in the Arachniodae. — Ed.

t [ § 280, Dana (Report, &c., loc. cit. p. 1339)
speaks of several small glands about the mouth,
and communicating with it by ducts, with the Cali-
goidea, and which are probably of a salivary
nature. These organs in Argulus have been care-
fully examined by Ley dig (Ueber Argulus, &c., loc.
cit. p. 333, Taf. XIX. fig. 2, a.), and especially as
to their relations to the spicula (see § 278, note 6)
of these animals. Leydig thinks they may as
well be regarded poisonous as salivary glands. See
my note under § 278, note 7. — Ed.

}

§ 280. TUB CRUSTACEA. 333

BapJmia , and Apus, alone, the anterior extremity of the intestinal canal
has several single or ramose caeca, the walls of which appear to serve prin-
cipally as hepatic organs.® With the Cirripedia, similar caeca exist on the
stomach,® and form, evidently, the transition to the hepatic organs of the
other Crustacea, — that is, to an isolated liver with special, though short excre-
tory canals. Such an isolated liver occurs with the Laemodipoda, Iso-
poda, and Amphipoda, and consists of long varicose caeca arising from the
base of the stomach, and accompanying the intestine a considerable dis-
tance.®

With the Poecilopoda, Stomapoda, and Bopyrina, the hepatic organs are
inserted at various points along the digestive canal.® Finally, with the
Decapoda, the liver consists of two glandular masses composed of more or
less ramose caeca loosely bound together. Each of these glands, which
sometimes occupies only the sides of the cephalo thorax, but sometimes, also,

largest portion of the alimentary canal dotted with
small, yellowish-brown follicles, which I can only
regard as hepatic organs, although other Zooto-
mists consider them as Malpighian canals (see
§ 287). L. Dufour (loc. cit. p. 96, PI. V. fig. 4,
B.) has found these follicles in the stomach of Scu-
tigera , but did not regard them as hepatic.

The numerous large cells, which, according to
Serves (Ann. du Mus. d’Hist. Nat. XX. p. 250),
cover the external tunic of the intestine of Litho-
bius , are certainly only follicles of this kind.*

5 With Daphnia , there are two lateral, back-
wardly-curved caeca, which ascend from the ante-
rior extremity of the digestive canal towards the
dorsal surface of the head ; see Schaffer , loc. cit.
p. 41, Taf. II. fig. 2, k. k. ; Straus , loc. cit. p.
401, PI. XXIX. fig. 6, s. o. 6., and Jurine , Hist. d.
Monocl. PI. IX. X. fig. 7, XI.-XIII. With
Branchipus , and Artemia {, Joly , loc. cit.), the
anterior extremity of the digestive tube has also
two short caeca which, with the glandular tunic
with which the remainder of the intestine is cover-
ed, should be regarded as a liver. With Argulus ,
the stomach has two multiramose caeca, which lie
in the parenchyma of the body ( Jurine , loc. cit. p.
441, PI. XXVI. fig. 1-3, 9, or Vogt , loc. cit. p. 8,
fig. 1, 9). With Apus , these caeca are given off
from the anterior extremity of the digestive canal
and do not extend beyond the anterior border of the
cephalothorax ( Schaffer , loc. cit. p. 70, Taf. V.
fig. 15, a. a.). According to Zaddach (loc. cit. p.
8, Tab. I. fig. 10-13, and Tab. IV.), these caeca
contain numerous glandular follicles. f

6 Beside the figures of these stomachic append-
ages in the works of Cuvier , Burmeister , and
Martin St. Ange , see also particularly those which
Karsten (Nov. Act. Nat. Cur. XXI. p. 301, Tab.
XX. fig. 1-4) has given of the hepatic organs sur-
rounding the pylorus with Balanus.

7 With Cyamus , there are two long hepatic
canals which wind over the digestive canal ( Rous-
sel de Vauzdme, loc. cit. p. 252, PI. IX. fig. 19).
The two stomachic appendages of Idothea which
Rathlce (loc. cit. p. 121) has taken for adipose
bodies, belong to the hepatic apparatus which here,
according to my observations {Muller's Arch.

* [ § 280, note 4.] Eor the liver of Julus , see
Leidy , loc. cit. lie says, “ At the termination
of the proventriculus, there open two biliary tubes,
and from it, surrounding the commencement of the
ventriculus, is suspended a broad, white, opaque,
reticulated band, apparently composed like the
rete adiposa of insects.” — Ed.

\ [ § 280, note 5.] The hepatic nature of these
appendages with Artemia and Argulus Is denied

1837, p. 435) consists of three pairs of yellow vari-
cose tubes. With Oniscus, Porcellio , Asellus ,
and Lygidium , there are four very long varicose
hepatic tubes which open right and left into the
pylorus ( Treviranus , Verm. Schrift. I. p. 57, Taf.
VII. fig. 38, Taf. IX. fig. 50, Taf. XI. fig. 64 ;
Brandt , Mediz. Zool. II. p. 75, Taf. XV. fig. 39 ,
Lereboullet , loc. cit. p. 130, PI. V. fig. 25 •, Kars-
ten, loc. cit. p. 296, Tab. XXVII. fig. 1). Tre-
viranus, who did not observe the excretory ducts
of these glands regarded them as masses of fat,
while Ramdohr (Abhandl. fib. d. Verdauungsw.
&c. p. 204, Taf. XXVIII. fifc. 5), who, probably by
mistake, has figured with Porcellio three similar
appendages, has taken them for salivary organs.
There are three pairs of hepatic canals with Cymo-
tlioa {Meckel, Syst. d. vergleich. Anat. IV. p. 154),
Aega {Rathkd, Nov. Act. Nat. Cur. XX. p. 30,
Tab. VI. fig. 16, d. d. 18), and Lygia {Milne Ed-
wards, Hist. Nat. d. Crust. PI. IV. fig. 3). I can-
not now decide whether Iiiella has really only one
varicose hepatic tube, or whether the others were
overlooked by Straus (loc. cit. p. 59, PI. IV. fig.
15). With Gammarus , and the other Amphipoda,
I have found two pairs of long hepatic tubes.

Frey and Leuclcart (Beitr. p. 104) have found
with Caprella , as with Cyamus , two simple hepa-
tic coeca.

8 With Limulus , there are four groups of inter-
laced caecal canals situated in both sides of the
cephalothorax. The bile is poured into the ante-
rior portion of the intestine by four distinct excre-
tory ducts, which are widely separated from each
other {Van der Hoeven , loc. cit. p. 18, PI. II. fig.

I, 5, 8). With Squilla, Bopyrus , and Phryxus ,
the digestive canal has ramose or varicose hepatic
caeca on both sides, at irregular intervals, of its
whole length {Muller, De Gland. Struct, p. 70,
Tab. IX. ; Duvernoy , Ann. d. Sc. Nat. VI. 1836,
p. 243, PI. XV. fig. 1 ( Squilla ) ; and Rathte, De
Bopyro et Nereide, p. 9, Tab. I. fig. 7, and Nov.
Act. Nat. Cur. XX. p. 47, {Bopyrus and Phryx-
us.) The genus Mysis {Frey, loc. cit. p. 19) on
the contrary, which has eight hepatic canals open-
ing right and left into the base of the stomach, re-
sembles again the Amphipoda and Isopoda.

by Leydig (Ueber Argulus, &c., and Ueber Ar-
temia, &c., loc. cit. Siebold and Kblliker's Zeitsch.

II. p. 334, and III. p. 286) on histological grounds 5
it is most probable however that they serve as a
liver, since Will {Muller's Arch. 1848, p. 506) has
shown, by chemical analysis, the hepatic nature of
analogous caecal tubes with Daphnia and Cyclops.
— Ed.

THE CRUSTACEA.

334

§§ 281, 282.

reaches even to the tail, pour their secretion, by a short duct, into the
digestive canal on both sides close behind the pylorus.®

§ 281.

With many Crustacea, the digestive canal is surrounded with fat-cells,
the contents of which are often of a beautiful orange or blue color. These
cells either consist of a few scattered globules/1’ or are disposed in lobes
of various forms.® This tissue is undoubtedly analogous to the Corpus
adiposum, so common in insects.

The fat which these cells contain, plays a part, probably, in digestion and
assimilation ; for with these animals the excess of nutriment is deposited as
fat to be used in times of need, as, for example, during the act of moulting.
This explains why the quantity found is so variable, or even may be
entirely wanting.

„ CHAPTER VI.

%■

CIRCULATORY SYSTEM.

§ 282.

Although the blood of Crustacea traverses the body by a very regular
circulation, yet, as with all the Arthropoda, the vascular system is here quite
imperfect, the blood-currents not always being contained in proper canals.
But a central, propelling organ is very rarely absent, and consists of a heart,
sometimes round and vesiculiform, sometimes long and tubular. With
the higher Crustacea, it is the point of departure of an arterial system
which, with the lower orders, gradually becomes abortive, and at last en-
tirely disappears. The more or less long arteries do not terminate periph-
erically in a capillary net-work, but the blood is freely effused into the

9 For the liver of the common crawfish, which is
large but contained in the cephalothorax, see the
descriptions and figures of Roes el , Suckoiv ,
Geveke , Brandt , and Schlemm, also those of Mul-
ler (De Gyand. Struct, p. 69). This last mentioned
author found the liver conformable with that of
many of the other Macrura and Brachyura. Milne
Edwards (Hist. d. Crust. PI. IV. fig. 5) has found,
with Maia , a hepatic mass very remarkable in being
symmetrically divided into several lobes. With
Pagurus , there is, on each side of the pylorus, a
long biliary vessel, which extends along the intes-
tine to the extremity of the tail, and into which
numerous lateral follicles empty their product ; see
Swammcrdamm , loc. cit. p. 86, Taf. XI. fig. 4, 5 ;
Muller , De Gland. &c. p. 70, Tab. VIII. fig. 12,

* [ $ 281, note 9.] For the intimate structure
of the liver of Crustacea, as elucidated by the

13 ; and Delle Chiaje , Descriz. &c. Tav. LXXXVI.
fig. 6/

1 These fat-globules, of an orange color, are often
found scattered about in Cyclops , Daphnia and
Gammarus.

2 Such lobes and of a blue color are found with
Branchipus on the sides of the digestive canal.
Other whitish adipose masses form a kind of net-
work around the intestinal canal of Lernaea , Ler-
naeocera and Lamproglena (Rathkt, Nov. Act.
Nat. Cur. XX. p. 129, and Nordmann , loc. cit. p.
6, 125, 132, Taf. I. fig. 4, Taf. VI. fig. 4). This
last observer has regarded this reticulated mass as
a liver. With the Myriapoda, these adipose
masses are large, lobulated, and occupy quite a
space in the visceral cavity.

microscope, see Leidy , Amer. Jour. Med. Sc. 1848,
XV. p. 1. — Ed.

THE CRUSTACEA.

835

§ 283.

lacunae which lie between the different visceral organs and appendages of
the body. But, notwithstanding the absence of vascular walls in these
interstices, the blood moves in determinate directions, until, after a course
of variable length, it is returned to the heart. During their course, the
blood-currents are often taken up by particular reservoirs, which, as venous
sinuses, may be regarded as forming the rudiments of the venous system.
In this manner, notwithstanding the imperfection of this vascular appara-
tus, all the organs constantly receive fresh blood, which is nowhere
stagnant ; also, the arterial may be clearly distinguished from the venous
currents, even when the arterial walls are wanting.

The Blood, itself, is either colorless, or of a faint red or violet hue.
These colors belong to the blood-liquid, and not to the contained globules,
which are few and always colorless. These globules are round, oval, or
pyriform ; their surface is rough, and they contain fine granules, and, often
a very large nucleus.®

§ 283.

The Heart of the Crustacea is always situated in the axis of the body,
directly under the shell, at the anterior part of the back, and is often
attached to the internal surface of the skeleton by muscular fibres.

Usually, its walls are thin and composed of scattered muscular fibres
interlaced in various ways. By the contraction of these fibres the blood is
propelled from behind forwards through the arterial orifices, — those of
the veins being closed at the same time by valves.

The number of these different orifices, and the form and divisions of the
Heart, have the following modifications :

1. With many of the lower Crustacea, especially with the Siphonosto-
ma, and the Lophryopoda, the heart is a simple, thin-walled sac, of
either a spheroidal or an elongated form, but invariably with only two
orifices, — a posterior or venous, and an anterior or arterial. (1)

1 For the blood of Crustacea, see Wagner , Zur
vergleich. Physiol, d. Blutes, p. 21. It is pale red
with the craw-fish ; I have found it deep red with
Apus , and violet with Gammarus . That of Pa-
linurus is also pale red, according to Lund and
Schultz (Isis, 1830, p. 1223). See also Nord-
mann , loc. cit. p. 73 (. Achtheres ) ; Joly, loc. cit.
p. 238 (Arter’iia) ; Zenker , loc. cit. p. 20 ( Gam -
mar us) ; Frey, loc. cit. p. 21 {My sis), and Carus,
Yon d. aiisseren Lebensbeding. d. weiss-und Kalt-
blutigen Thiere, p. 80.

1 The heart is round or ovoid, and its pulsations
quite frequent, with Daphnia, Lynceus, Poly-
phemus, and Evadne, where it is situated at the an-
terior part of the back, and very easily seen (see the
figures of it given by Straus, Jurine, and Lovin,
loc. cit.). According to Nordmann (loc. cit. p.
11), there is also a round heart in the cephalo-
thorax of Ergasilus. Jurine (Hist. d. Monocl. p.

57. PI. Y. fig. 4) thinks he has observed a distinct
auricle underneath the heart of Cyclops ; but for
my own part I have been unable to see it. As to a
second or ventral heart, situated under the dorsal
heart, which, according to Perty (Isis, 1832, p.
725), is found with Daphnia, I have been as unable
ms Wagner (Yergl. Anat. 1834, p. 166) to find it.
With Argulus, the heart is long and situated under
the dorsal shell, as Vogt (loc. cit. p. 9, Taf. I.
fig. 1, 10, M.) has shown, contrary to the opinion
of Jurine (loc. cit. p. 437, PI. XXVI.). With
Achtheres , Dichelestium, Chondr acanthus , the
heart consists of a long cylindrical tube {Nord-
manrt, loc. cit. p. 73, and Rathkt , Nov. Act Nat.
Cur. XIX. p. 153, and XX. p. 125). The anterior
and posterior valvular system which Pickering
and Dana (Isis, 1840, p. 206) have seen with € ali-
gus, lead us to think that here also there is a heart
between these valves.*

* [ § 283, note 1.] With C aligns, the circula-
tion is wholly lacunal, and appears to consist of
broad irregular streams, passing through the
spaces left by the internal organs, — there being in
no part distinct vessels. A single centre of circu-
lation, or a heart, can scarcely be said to here exist,
but there are two points in the median line where
there is a valvular action, and which perhaps per-

form the functions of this organ ; see Dana , Cali-
gus, &c., Amer. Jour. Sc. XXXIV. p. 257, PI. III.
fig. 6, a. 6, b.

A corresponding structure has been found with
Argulus, by Leydig (loc. cit. Siebold and Kolli-
ker's Zeitsch. II. p. 335, Taf. XIX. fig. 3), who has
given, moreover, many histological details upon the
circulatory system of these animals. — Ed.

336

THE CRUSTACEA.

§ 283.

2. With the other Crustacea, excepting the Myriapoda, the heart has,
likewise, the form of a short simple sac, or that of a simple tube. In
both cases, it is perforated by very numerous arterial and venous orifices.
During the systole, the blood is propelled through the arterial orifices lead-
ing, nearly always, into vessels of the same nature ; at the same time, the
venous orifices are closed by valves, which open, however, during the diastole,
to allow the ingress of the blood into the heart. With the Decapoda, the
heart is vesiculiform, situated in the middle of the cephalothorax, and its
projecting corners often give it a star-like aspect. This heart has arteries
passing off in front, behind, and below, and the returning venous blood
enters it through venous orifices on its upper lateral portion.® With the
Poecilopoda, Isopoda, Amphipoda, and probably, also, with the Laemodi-
poda, and Cirripedia, the tubular heart, occupying a large portion of the
anterior and middle regions of the back, sends off arteries before, behind,
and laterally, and receives the venous blood through lateral venous ori-
fices.® This organ is most highly developed with the Stomapoda, where
it occupies nearly the whole length of the body like a tube ;(4) but with the

2 There are, usually, in the polygonal heart of
the Decapoda, three anterior arterial orifices, two
below and one behind. These open distinctly into
as many main arteries 5 see S warn m e rdam m, loc.
cit. p. 87, Taf. XI. fig. 8 (Pagurus) Roesel , loc.
cit. p. 58, Taf. IX. fig. 14, and Suckow , loc. cit.
p. 58, Taf. IX. fig. 1, Taf. XI. fig. 2-4 ( Astacus ) ;
Audouin and Milne Edwards , Ann. d. Sc. Nat.
XL. 1827, p. 353, 363, PI. XXIV. XXVIII. fig. 1 5
and Milne Edwards , Hist. d. Crust. PI. V. VII.
(Mata and Homarus ), and Cyclop, of Anat. loc.'
cit. p. 775, fig. 418 (Cancer). Not so easily seen
are the six venous orifices which always are only
valvular fissures, chiefly because they do not open
into veins. According to Lund , and A. fV. F.
Schultz (Isis, 1825. p. 594, Taf. III. fig. 2-4 5
Ibid. 1829, p. 1299, (Homarus), and 1830, p. 1226,
with the figure of p. 1228, (Mata)), the heart of the
macrourous Decapoda has two upper, two lower, and
two lateral venous orifices, while that of the Brachy-
ura have only four upper and two lateral. Krohn
(Isis, 1834, p. 524, Taf. XII. fig. 1-3), has con-
firmed this observation with the crawfish. Suckow,
however (loc. cit. p. 58, Taf. XI. fig. 2, a. a.), did
not perceive in this species only the two upper ori-
fices, while Audouin and Milne Edwards (Ann.
d. Sc. Nat. loc. cit. p. 357, 364, PI. XXVI. lig. 3,
N.111-) have not observed in the heart of Homarus
and Maia only the two lateral orifices. This
last naturalist (Hist. d. Crust. I. p. 94. PI. V. VI.)
refuses to admit the description of the heart of
the Decapoda given by Lund, and brings to
his support ( Cyclop, loc. cit. p. 777) Hunter's
preparations of the lobster -, but, judging from the
beautiful figures of them given by Owen (Catal. of
the Physiol. Ser. II. PI. XV. h. h. PI. XVI. lig. 2,d.
d. and especially fig. 1, f. f. f.) these are just the pre-
parations to support the view of Lund, Schultz,
and Krohn. I, at least, have perceived distinctly
the upper, lower and lateral venous orifices, as
“ the three orifices of the veins passing into the
heart, f. f. f.” See also the description of Owen
of the heart of the lobster in his Lectur. on Comp.
Anat. p. 179, fig. 91.

3 For the heart of Limulus , see Straus, Consid.
g6n. sur 1’ anat. comp, des anim. articul^s, p. 346,
and especially Van der Hoeven, loc. cit. p. 18,
PI. II. fig. 9. Beside the anterior and poster-
ior arterial orifice, there are, with these Crus-
tacea, seven others belonging to the seven pairs
of lateral arteries, and on the dorsal portion
of the organ, an equal number of valvular open-
ings belonging to the venous system. With the

Isopoda, the tubular heart is continuous with
an anterior and a posterior aorta 5 it receives only
three to five pairs of lateral vessels which have been
regarded sometimes as arterial and sometimes as
venous 5 see Treviranus, Verm. Sclirift. I. p. 58.
65, Taf. VIII. fig. 46, and Taf. IX. fig. 55 (Por-
cellio and Armadillidium) ; Brandt , Med. Zool.
II. p. 75, Taf. XV. fig. 38 (Porcellio) ; . Lereboul -
let , loc. cit. p. 131, PI. V. fig. 33 (Lygidium)',
Rathkt, in the Neuest. Danzig. Schrift. I.p.122 (Ido-
thea), and Nov. Act. Nat. Cur. XX. p. 31 (Aega).
It is, however, very probable that these orifices are
arterial, for they open into vessels, and, moreover,
the venous orifices are found, as with Lim ulus, on
the dorsal surface of the organ. For the Am-
phipoda, Gammarus pulex may be cited as a
type, and of which the heart as a cylindrical ves-
sel occupies the axis of the anterior segments of the
body. In this animal may be very easily seen
how the blood, with the diastole, enters the heart
through the several dorsal venous orifices, and
how, with the systole, it is thrown forwards, back-
wards and laterally through the arterial openings.

We have not yet complete researches on the
heart of the Cirripedia *, but since Martin St. Ange
(loc. cit. p. 18) states that these animals have a
dorsal vessel with lateral trunks, it may be con-
cluded that their heart is like that of the Amphi-
poda, Isopoda, &c. As to the Laemodipoda, we
have only the imperfect details given by Trevi-
ranus (Verm. Schrift. II. p. 8), and Roussel de
Vauztme (loc. cit. p. 254), according to which
there is, with Cyamus, only a simple tube opening
before and behind *, and we are therefore unable to
say whether this heart is formed after the first or
second type indicated in the text.

4 With Mysis, the heart consists, according to
Frey (loc. cit. p. 21), of a dorsal vessel extending
from the cephalothorax into the back part of the
body ; but the blood enters it only through a
posterior Ostium venosum, and passes out into
the body through an anterior Ostium arteriosum.
If this organization is confirmed, Mysis will differ
remarkably in this respect from the Isopoda, Am-
phipoda, &c., but especially from another Stoma-
pode genus, — Squilla ; for in this last, the heart
with its anterior, posterior and lateral orifices,
reaches its greatest development, occupying the
entire abdominal cavity except the cephalothorax,
and sends off laterally fourteen to seventeen pairs
of arteries, beside being perforated on its upper
portion by various pairs of venous orifices •, see
Duvernoy, Ann. d. Sc. Nat. VIII. 1837, p. 42, PI.

§284.

THE CRUSTACEA.

337

Phyllopoda, it is less elongated and has numerous constrictions, thereby
resembling the following type.®

3. This type, the third, is found with the Myriapoda, and considerably
resembles that of the so-called Dorsal Vessel of the Insecta. With the
Chilognatha, and Chilopoda, it consists of a more or less articulated tube,
occupying the whole dorsal line of the body. It is divided by constric-
tions and imperfect muscular septa into chambers, nearly as numerous as
the segments of the body. Each chamber is attached, as with the Insecta,
right and left to the internal surface of the segments of the body, by tri-
angular muscles. The Diastole is produced chiefly through these muscles.
At its anterior extremity, this dorsal vessel passes through an Ostium arte-
riosum into an aorta, while, from the posterior extremity of each of these
chambers are given off two lateral arteries. The returning blood enters the
heart through the two venous orifices on the dorsal surface of each compart-
ment. The Systole consists of an undulating action from behind forwards,
and the blood is thereby propelled partly from one chamber to the next
forward, and partly into the lateral arteries.®

§ 284.

The Circulation outside of the heart, with the Crustacea, has very varied
relations, as has already been mentioned. With the lower Crustacea, with
the Siphonostoma, the Lophryopoda, and the Phyllopoda, the blood forms
regular' currents in the iutervisceral lacunae and interstices, but there is no
trace of vascular walls. The aortic current, shortly after leaving the heart,
divides into a right and left portion, which, also, sub-divide, enter the
appendages of the cephalic extremity, then turn and run along the abdom-
inal surface of the body — furnishing, in their course, several lateral, loop-
like currents, which enter the locomotive organs, then turn again towards
the posterior extremity of the back, where they enter the heart.®

II. fig. 1, and especially Au do uin and Milne Ed-
wards, Ibid. XI. 1827, p. 376, PI. XXXII. These
last naturalists have very distinctly represented
the dorsal venous orifices of the heart just men-
tioned.

<r> With Branchipns , Artemia , Isaura , and
Apus , the heart which has several constrictions
and whose venous orifices are very apparent, occu-
pies the entire dorsal median line excepting in the
caudal extremity -, see Jolt/ , Ann. d. Sc. Nat.
XIII. p. 239, PI. VIII. fig. 4, j., XVII. p. 307, PI.
IX. fig. 43, r. ; also Krohn ,4k'roriep\s neue Not.
XLIX. p. 305, fig. 1, 2 *, and Zaddach , loc. cit. p.
17, Tab. I. fig. 17, C., Tab. II. fig. 4-14.*

<’> Although Treviranus (Verm. Schrift. II. p.
31, Taf. VI. fig. 6), and Kutorga (loc. cit. p. 18)
have, indeed, furnished some communications on
the heart of Lithobius and Scolopendra , yet we
are really indebted for what is known of the struc-
ture of this organ with the Myriapoda to the excel-
lent researches of Newport ,• see Philos. Trans.
XXIII. p. 272, PI. XIII. fig. 18-22 {Scolopendra),

* [ § 283, note 5.] See also Ley dig, loc. cit. Sie-
Uold and KollikePs Zeitscli. III. p. 287 {Artemia
and Branchipus). — Ed.

t [§ 234, note 1.] This statement of the com-
plete absence of true vessels in Argulus , is con-
firmed by the researches of Leydig (loc. cit.

29

and fig. 25 {Scutigera). According to these in-
vestigations, the interventricular septa are scarcely
developed with the Chilognatha, although very
much so with the Chilopoda.

l An extra vascular circulation has been ob-
served with the Lernaeodea, by Nordmann (loc.
cit. p. 73, 98), and with the Caligina, by Picker-
ing and Dana (Isis, 1840, p. 205, 1841,* Taf. IV.).
Jurine (loc. cit. p. 437, PI. XXVI. fig. 8), and,
with more exactness, Pogt (loc. cit. p. 9, Taf. I.
fig. 10), have described the circulation with Argu-
lus. For that of Daphnia, see Gruithuisen ,
Nov. Act. Nat. Cur. XIV. p. 403, Tab. XXIV. fig.
6 •, Perty, Isis, 1832, p. 725, and Ehrenberg,
Abhandl. d. Berl. Akad. 1835, p. 189, note. Zad-
dach (loc. cit. p. 23, Tab. I. fig. 17) has repre-
sented in much detail that of Apus. In order to
be convinced of the entire want of vascular walls
with the lower Crustacea, there is perhaps no
species which will serve better than Argulus foli-
aceus whose body is wholly flattened and trans-
parent throughout, t

Siebold and KollikePs Zeitsch. II. p. 337) upon
this same species. Ilis schema of the circulation
with these animals is as follows: “The blood is
thrown from the heart into the interstitial lacunae
of the organs *, thereupon it is collected in the
posterior portion of the heart *, a portion of it

338

THE CRUSTACEA.

§ 284.

With the other Crustacea, with which the heart is un articulated, the blood
passes from this organ into arterial canals ; but the walls of these last sooner
or later entirely disappear, so that here also the blood circulates at liberty
between the interstices of the body. The regular arterial currents thus
formed finally bend about and become those of the venous system. With
the Isopoda, and the Amphipoda, perhaps, also, with the Poecilopoda, and
Laemodipoda, the anterior, posterior, and lateral arterial trunks disappear
after a very short course.®

With the Stomapoda, and Decapoda, the arterial system is pretty well
developed, and can be traced even to its ultimate ramifications. With the
first, the heart, at its anterior extremity, sends otf a simple, pretty long
aorta, which ramifies to the eyes and tentacles; while from its sides, pass
off numerous arteries for the segments of the body and their appendages,
and, posteriorly, a branch which extends to the very extremity of the
tail.'3’

With the Decapoda, on the other hand, the heart has three anterior
aortae, of which the middle one goes, almost unbranched, to the eyes, while
the two lateral, belonging to the antennae, give off, in their course, branches
to the cephalo-thoracic organs. The two hepatic organs, alone, have special
arteries, which arise directly from the lower surface of the heart. Behind,
there is a posterior aorta which, immediately after its origin, divides into
a dorsal and an abdominal branch. The first of these, either simple as
with the Macrura, or bifurcated as with the Brachyura, extends even to
the end of the tail, sending off branches right and left. The second passes
below, and is distributed principally to the feet, the pincers, the foot-jaws,
and the maxillae. (4>

2 According to the researches of Treviranus
(Verm. Schrift, I. p. 78) upon Asellus, and of
Zenker (loc. cit. p. 21) upon Gammarus , the
arterial system is very rudimentary with the Iso-
poda, and Amphipoda. This may be easily proved
by an examination of allied species. It may be asked,
however, if the blood-currents of these Crustacea
are not enveloped in vascular walls so delicate as to
escape observation ; but with proper care one may
be satisfied that no such walls exist. From mus-
cular contractions or the bending of the articula-
tions, the current of the blood is often stopped, and
then the blood-globules evade the obstacle by
passing at any point directly from the arterial into
the venous current.

Goodsir (Edinb. new Philos. Jour. July, 1842,
p. 184) was certainly deceived when he affirmed that
lie had observed the blood of Caprella circulating
in arterial and venous vessels.

The absence of vascular walls with Caprella ,
already observed by Wiegmann (Arch. 1839, I.
p. Ill), has been confirmed by Frey and Leuck-
art (loc. cit. p. 104, Taf. II. tig. 19, 20), and, ac-
cording to them, the circulation here is analogous
to that of the Amphipoda.*

enters this organ without passing to the branchiae,
but the other portion traverses the gills and after-
wards returns to the heart.” — Ed.

* [ § 284, note 2.] In a private letter Agassiz
has communicated some interesting facts on the
circulation of Caprella. He says “ Caprella has
a tubular, dorsal vessel with lateral valves, exactly
like the larvae of Insecta, — the blood is emptied, in

3 This disposition of the arterial system has
been observed by Audouin, Milne Edwards , and
Duvernoy (Ann. d. Sc. Nat. XI. 1827, p. 377, PI.
XXXII. and VIII. 1837, p. 33, PI. II. fig. 1), with
Squilla , while Mysis appears from its circulatory
organs to be allied to the Isopoda and Amphi-
poda ; see Thompson , Zool. Research, loc. cit. I.
p. 13, and Frey , loc. cit. \r. 13.

4 The arterial system of Mala and Homarus has
been described with many details in the so-often-
quoted memoir of Audouin and Milne Edwards
(Ann. d. Sc. Nat. XI. 1827, p. 352, PI. XXIV.-
XXIX.). Lund , also (Isis, 1825, p. 393, Taf. III.
fig. 1), has very well described the arteries of the
lobster. But especially should be noticed the ex-
cellent preparations of Hunter of the arterial sys-
tem of this same animal (Catal. of the Physiol. Ser.
II. PI. XV .-XVIII X For this system with the
crawfish, see Brandt , Med. Zool. loc. cit. p. 63,
Taf. XI. fig. 2 *, and for that of Cancer pa gurus ,
Milne Edwards , in the Cyclop, loc. cit. p. 775, fig.
418.

front, into the main cavity of the body, moves back-
wards along the lower part of that cavity without
being enclosed in vascular walls, and returns to
the dorsal vessel through the lateral valves. The
circulation was traced in a living animal into which
a solution of a small quantity of carmine had been
injected.” — Ed.

THE CRUSTACEA.

339

§ 284.

With all the Crustacea, the venous currents gradually converge from
the lower part of the body into various intercommunicating sinuses, situ-
ated, some upon the median line, and others at the base of the feet.®
From these sinuses the blood proceeds to the branchiae, and thence into
the dorsal sinus the walls of which are thin and uncontractile, and within
which the heart is entirely enclosed. This dorsal sinus is filled during the
systole, and the arterialized blood which it contains is absorbed during the
diastole through the venous orifices of the heart, without any aid on the
part of the walls of the sinus.®

With the Myriapoda, also, the arterial system is highly developed. Not
only are there numerous arteries arising from the sides of the heart, which
ramify in the segments of the body, but also, beside an anterior dorsal
aorta, two other considerable arteries which embrace the oesophagus, then
bend below and unite to form, on the abdominal cord, a Supra-spinal artery.
This artery gives off numerous lateral branches, which accompany the
principal nerves, and terminate, at last, in ramuscules.<7)

But what distinguish the Myriapoda from the higher Crustacea, are
the venous currents, which, equally extra-vascular, do not run towards the
respiratory organs, but pass directly into the dorsal sinus, and thence are
absorbed into the chambers of the heart through the venous orifices.®

5 Of the absence of vessels around the venous
currents one may easily be convinced from an ex-
amination of small Araphipoda and Isopoda.
This absence exists also with the higher Crustacea}
see Duvernoy , Ann. d. Sc. Nat. VIII. 1837, p.
34, or in Cuvier , Lemons d. Anat. Comp. VI. p.
404 ( Squilla ). I am quite of the opinion of Lund
and Schultz (Isis, 1830, p. 1225), who have
combated the opinion of Audouin and Milne Ed-
wards and have described the venou3 system of
the Decapoda as having proper walls (Ann. d. Sc.
Nat. PI. XXVI.-XXXI.). But Milne Edwards ,
who, at this time, advocates with so much zeal the
wall-less condition of the circulating currents with
Mollusca, appears, moreover, to entertain the
opinion of a similar circulation with the Decapoda ;
at least, such would be inferred from what he has
said upon the circulation in general of Crustacea ;
see Ilist. d. Crust. I. p. 101, and Cyclop, loc. cit.
p. 777.

0 According to Audouin and Milne Edwards
(loc. cit. PI. XXVI. fig. 3), the returning blood
from the branchiae enters the heart direct through
inter-anastomosing vasa branchio-cardiaca. But
this statement has been reasonably doubted by va-
rious observers, for these naturalists had overlooked
the sinus which envelopes the heart of the higher
Crustacea, and receives, first of all, the branchial
blood ; see Straus , Consider. &c. p. 345 ; Lund
and Schultz , Isis, 1830, p. 1226 } and Krohn ,
Ibid. 1834, p. 522. This dorsal sinus has been

compared sometimes to an auricle, sometimes to a
pericardium ; but, strictly speaking, neither of these
comparisons is correct.

7 The division of the anterior dorsal aorta, with
Scolopendra, w&s first noticed by Straus (Consider.
&c. p. 347). More detailed researches on the arterial
system of the same have been published by Ku-
torga (loc. cit. p. 18, Tab. III.), and Lord (Med.
Gaz. part VI. vol. I. 1837, p. 892), who were
chiefly occupied with the supra-spinal artery. But
of all the observers, Newport (Philos. Trans. 1843,
p. 274, PI. III. XIV.) has worked out the arterial
system of the Myriapoda in the most complete and
masterly manner. His researches have shown
that this system is least developed with the Julidae,
and rises gradually through the Glomeridae and Ge-
ophilidae — reaching its highest grade of structure
with the Scolopendridae. Kutorga has entirely
mistaken the nature of the heart in regarding it as
a vena cava, and the supra-spinal artery as an
aorta. Gaede , also (Zool. Magaz. I. p. 108, Taf.
I. fig. 7, g. f.), is quite in error as to the vascular
system of Scolopendra ; for he has evidently seen
the three vessels arising from the anterior extrem-
ity of the heart, namely : the dorsal aorta and the
two vessels which, uniting, form the supra-spinal
artery } but he has taken them for nerves.

8 Newport , who has so well observed the circu-
latory system of the Myriapoda, says nothing of
veins, and describes the dorsal sinus as a pericar-
dium.

340

THE CRUSTACEA.

$ 285.

CHAPTER VII.

RESPIRATORY SYSTEM.

§ 285.

The majority of Crustacea respire by Branchiae ; but among the lower
orders, there are many which have no trace of respiratory organs, while the
Myriapoda respire by aeriferous tracheae.

With most Siphonostoma, Lophyropoda, and many Stomapoda, there are
no particular respiratory organs, the respiration being, therefore, cutane-
ous ; and with some species of these orders, the water is renewed by the oar-
like action of some of the locomotive organs.®

The Branchiae of Crustacea are sometimes lamelliform, sometimes cylin-
drical, and often appear either distinct and separate, or consist of compound
serrated organs, branched in various ways, on which the branchial lamellae
are disposed in a regular row, and the branchial tubes united in larger and
smaller tufts. But these lamellate or tubular branchiae are invested with
a membrane so thin that it widely differs from those of the other regions of
the body. It is never ciliated, and is usually without fringes, bristles,. &c.
The interior of these organs presents only a few parenchymatous points,
and, whatever may be their form, they are always traversed by numerous
canals and large interanastomosing lacunae, which are wholly without
proper walls, and are filled by the arterial and venous currents.®

The branchiae are often in connection with their neighboring append-
i ages. These last consist of multi-articulate lashes or cirri, or of scales, or
large plates, and serve either as gyratory organs, or as opercula shielding
the respiratory organs ; sometimes, indeed, they perform both of these
functions at the same time. Nearly always these organs are fringed with
long, stiff, and often pinnate bristles.®

1 The branchiae are wanting with the Penellina,
Lcrnaeodea, Ergasilina, and with some Caligina.
With Daphnia , Lynceus , and some other allied
Lophryopoda, the small oar-like feel concealed
under the belly are probably designed for the agi-
tation of the water, while the two feet projecting
in front of the body, and which are larger and
usually branched, are the principal swimming,
organs. Indeed, even when these animals are at
rest, these organs are seen in perpetual motion —
thus causing in the cavity of the shell a continual
current of fresh water ; this supports the observa-
tion of Ehrenberg (in his third Beitr. loc. cit. p.
189, note) that, with these Entomostraca, the inter-
nal surface of the valves performs the function of
branchiae. The active, hairy, clavate corpuscles
inserted on the base of the first pair of feet with
Cyclopsina castor , and which have been usually
regarded as posterior antennae ( Mailer , Entomostr.
p. 106, Tab. XVI. fig. 5, 6, c., or J urine , Ilist. d.
Monad, p. 52, PI. IV. fig. 1, PI. V. fig. l.b. PI. VI.
fig. 13, a.), are nothing but organs for the agitation
of the water. With Cypris , only, are there perhaps
special branchial organs. These little animals
have at the base of the posterior pair of jaws two
semilunar, pectinated plates, curved upwards, hav-
ing completely the aspect of branchiae ; see Ram-
dohr , Beitr. loc. cit. p. 15, Taf. IV. fig. 3, B. and
fig. 8, L. *, also Straus, loc. cit. p. 49, PI. I. fig.
4, o. and fig. 8, e., or Baird , in the Magaz. of Zool.

and Bot. I. p. 520, PI. XVI. fig. 8. These organs
appear to have been wholly misapprehended by
Treviranus (Verm. Schrift. II. p. 59, Taf. IX. fig.
5). With My sis , Leucifer , and Amphion , there
are no traces of branchiae, while with the other
allied Stomapoda, such as ALima and Phyllosoma ,
they sometimes exist in a rudimentary form. As
branchiae, have been regarded, also, the articulated
processes of the cloven feet of My sis and some
other Stopaapoda •, but, certainly, they are organs
for swimming or for the agitation of the water, and
their organization has nothing in common with that
of branchiae.

2 It is owing to this small quantity of paren-
chyma in the lamelliform branchiae and to the
numerous lacunae filled with blood that, when the
circulation in these organs is arrested, the two
lamellae of which they are composed, separate
from each other, and the whole branchia, swollen
from accumulated blood, has the form of an am-
pulla. The blood then changes its natural color.
This pathological state may be easily seen with in-
dividuals of Asellus , Gammarus , and Apus , when
allowed to be a long time dying. These ampullae
are violet, with Gammarus ; and of a beautiful red,
with Apus ; see my note upon the ampullae of
Apus cancriformis , in the Isis, 1831, p. 429.

•3 Hairy and bristled appendages 0T this nature
are often taken for branchiae. These organs are
not only surrounded by a thick skin which of it-

%

$ 286.

THE CRUSTACEA.

341

The branchiae are usually inserted at, the base of the anterior true feet,
or the posterior false feet, floating freely in the water ; or, they are con-
tained in a special respiratory cavity, into which water is admitted through
various ways.

§ 286.

The principal differences observed with the Crustacea in the disposition
and structure of their branchiae, are the following :

1. Many genera of the Caligina and Argulina, have upon various parts
of their body, such as the back, the abdomen, and the tail, several thin,
simple, naked lamellae, which may be regarded as branchiae.®

2. The feebly-developed branchiae of the Lepadea consist of cylindrical
or lanceolate processes inserted at the base of some of the cirrate feet, and
curved towards the back of the animal, so that they are always concealed in
the cavity of the shell. But the water is renewed upon their surface by
the regular movements of the long posterior feet.® With the Balanodea,
the branchiae have left the body of the animal, and are developed on the
internal surface of the mantle as more or less numerous soft folds or lamel-
lae.®

3. With the Laemodipoda, and some Stomapoda, the branchial appara-
tus is reduced to a few vesicular or cylindrical, sometimes wholly rudiment-

self would render them unfit for the respiratory
function, but they are not traversed except by feeble
blood-currents which do not enter the bristles or
hairs. From the complete absence of ciliated epi-
thelium, the vortex-producing organs are of much
importance. On this account, many species with
which these organs are wanting, use their feet for
this jnirpose.

1 Euryphorus has four such pedunculated
branchial lamellae on the dorsal surface of the two
grand segments of the body. These are what
Milne Edwards (Hist. Nat. d. Crust. III. p. 462,
PI. XXXIX. fig. 1) has called Appendices tty-
troides. With Dinematura} the last pair of feet
is changed into two naked, deeply-fissured bran-
chial lamellae ( Kroyer , Isis, 1841, p. 275, Taf. I.
fig. 5, i.). With Phyllophora, the branchial ap-
paratus is still more fully developed, for each foot
of the last four pairs terminates with two ovoid,
glabrous, branchial lamellae ( Milne Edwards ,
loc. cit. III. p. 471. PI. XXXVIII. fig. 14).
The two thin, lanceolate caudal lamellae of
Argulus , through which pass strong blood-cur-
rents interrupted only by some islets of sub-
stance, are certainly respiratory organs to which
the oar-like organs which Jurine (loc. cit. p.
442) has erroneously considered as branchiae,
serve as vortex-producing organs. I am yet un-
determined if the respiration is performed by these
lamellae alone, or in part by the lateral portions of
the dorsal shield through which pass numerous
blood-currents. But in any case, I cannot believe

* [§ 286 note 1.] Ley dig (loc. cit. Siebold and
Kolliker's Zeitsch. II. p. 337) has carefully exam-
ined the intimate structure of these caudal append-
ages with Argulus ; they are composed, 1st, of
simple glands such as are found under the skin over
the whole body ; 2nd, of a rich muscular net- work*,

29*

it possible, as has Vogt (loc. cit. p. 11), that these
lateral portions are the only respiratory organs of
these animals.*

2 In the various species of Lepas , there are
from two to five arcuate branchiae which hang
from each side at the base of the first pair of cirri.
With Cineras , beside the six branchiae, there is
one, very short, upon the back of the animal, at the
base of the third, fourth, and fifth pairs of feet \
while with Otion , there is a seventh pair inserted
on the second pair of feet*, see Mertens in Mul-
ler's Arch. 1835, p. 502 *, Wagner , Lehrb. d.
vergleich. Anat. p. 200 *, Cuvier , Mem. loc. cit. p.
6, fig. 2, 5, o. p. ; Burmeister , Beitr. &c. p. 31,
PI. I. fig. 14, c. c., and Martin St. Ange. M6m.
loc. cit. PI. II. fig. 17, 19, Iv. K. {Lepas).

3 These branchial lamellae are extraordinarily
developed with Coronula diadcma { Burmeister ,
Beitr. &c. p. 38, Taf. II. fig. 10, a. a.). They are
few in number with Balanus { Cuvier , Mem. loc.
cit. p. 14, fig. 18, c. c.). It is true that Burmeis-
ter subsequently (Ilandb. d. Naturgeschicht. p.
551) did not regard as branchiae but rather as
ovarian sacs, these organs which as to form and
position correspond somewhat to the branchiae of
certain Branchiopoda {Lingula). But even if
they do serve at the same time as receptacles of the
eggs, this would be no reason for refusing to the
folds of the mantle of the Balanodea the function of
a respiratory organ, for, with other lower animals,
as for example with the Lamellibranchia, the
branchiae serve as receptacles for the eggs.

and 3rd, of a lacunal net-work {Liiclcennetz).
The glands and the muscles constitute what is de-
scribed above as the islets of substance. Leydig
denies that these lamellae, thus composed, have,
peculiarly, a gill function. — Bu.

THE CRUSTACEA.

842

§ 286.

ary appendages, which hang freely from the base of some of the feet, or
are inserted isolatedly on the sides of the body.'4’

4. The Phyllopoda have, at the base of each of their numerous swim-
ming feet, an ovoid or lanceolate branchial lamella, pointing forwards.
It is quickly distinguished by its thin, glabrous covering, in opposition to
that of the other divisions of feet, which are bristled.®

5. With the Amphipoda, the rapacious and ambulatory feet, excepting the
first and last pairs, are those only which are provided with respiratory organs.
These last consist of oval or round glabrous lamellae, situated internally at
the base of the five middle feet. They receive, constantly, fresh water by
the movements of the three anterior pairs of post-abdominal feet, which
act as gyratory organs.®

4 With Phyllosoma , there is, at the base of the
anterior feet, a small, ovoid, pedunculated append-
age, which may perhaps be regarded as a rudi-
mentary branchia ; see Milne Edwards , Ilist.
Nat. d. Crust. II. p. 474, PI. XXVIII. fig. 15, a.
It is remarkable that, with another Stomapode
genus, Squilla, there are at the base of the ten
rapacious feet similar pedunculated appendages of
the form of oval lamellae ( Milne Edwards, Ilist.
Nat. d. Crust. II. p. 512, PI. XXVI. fig. 15, PI.
XXVII. fig. 13, 14, b.). These, also, would be re-
garded as rudimentary branchiae, did not these
Crustacea have distinct branchial organs (see
below). With Alima , the oval feet have some-
times very rudimentary branchiae in the form of
simple vesicles or ramified processes (Milne Ed-
wards, loc. cit. II. p. 506). With Caprella , and
Aegina, the first two posterior abdominal seg-
ments have, upon the sides, a simple, very soft,
pyriform branchia 5 while with Leptomera , there
is a vesicle of the same nature at the base of the
six feet of the first three posterior abdominal seg-
ments *, see Muller , Zool. Panic. Tab. LVI. fig. 5,
and Tab. Cl. fig. 2 ; Templeton, Transact, of the
Entomol. Soc. I. p. 193, PI. XXI. fig. 7, f. ; and
Kriiyer, Naturhist. Tidskr. IV. p. 490, PI. VI.-
VIII. With Cyamus , the respiratory organs are
even more devefoped. They consist of four long,
simple cylinders inserted 011 the sides of the first
two posterior abdominal segments, and projecting
over the back 5 see Treoiranus, Verm. Schrift. II.
p. 9, Taf. I. fig. 1-3, and Beobacht. aus. d. Zoot. u.
Physiol, p. 32, Taf. VII. fig. 48 — 50 ; also Kriiyer ,
loc. cit. IV. p. 474, PI. V. fig. 70-76 ■, and Roussel
de Vauztme, loc. cit. p. 248, Pi. VIII. *, according
to this last mentioned author, Cyamus ova/is has
four double, branchial cylinders. These branchiae
of Cyamus have often been taken for metamor-
phosed feet, but it is only necessary to examine
them in their earliest condition in order to be con-
vinced that they are special organs (Milne Ed-
wards, Ann. d. Sc. Nat. III. 1835, p. 329, PI. XIV.
fig. 14). At this epoch they are as pyriform as those
inserted on the side of the feet of Leptomera. The
passage to Squilla, whose branchiae are more highly
developed, is made by Cynthia. Each anal foot has
here a bifurcated branchia, the two cylindrical
divisions of which are curved towards each other *,
see Milne Edwards, Hist. Nat. d. Crust. II. p.
462, PI. X. fig. 5.

o The delicate branchial lamellae usually assume
after death the form of vesicles, from being filled
with blood, a phenomenon already mentioned (§ 285,
note 2). But, formerly, they were taken for special
organs whose function was unknown, and Berthold
(Isis, 1830, p. 693) has regarded those of Apus as
male genital organs •, while the remaining pilose
divisions of swimming feet were, according to him,
respiratory organs.

These branchiae are easily perceived with Apus
after death, and from the form which they then
assume, they have long been known as the prob-
lematical red sacs (Schaeffer, loc. cit. Tab. II. II*..
VI. •, Zaddach , loc. cit. p. 14, Tab. II. fig. 13, B.
Tab. XIV.). In 1830 (Isis, p. 429) I gave the cor-
rect interpretation of these organs which, like the
swimming feet of these animals, diminish in size
from before backwards ■, but, already, before me,
Loschge (Naturforsch. Stuck. XIX. p. 68, Taf. III.
fig. 6, 7, 10) had recognized their nature. With
Limnadia, and lsaura , the branchiae are very
long and of a brown-red color, but are wanting on
the last swimming feet *, see Brongniart, loc. cit.
p. 86, PI. XIII. fig. 7, 8 •, Straus, Mus. Senckenb.
loc. cit. p. 124, Taf. VII. fig. 13, 14, r., 15, k. *,
Joly , loc. cit. p. 299, PI. VII. fig. 2, 6, 7, f. and
PI. VIII. fig. 8, f. With Chirocephalus, Bran-
chipus, and Artemia, they have a more oval form
and exist on all the swimming feet. Rathlct (Zur
Fauna der Krym. p. 108, Taf. VI. fig. 14, 19-21),
has figured, probably from dead individuals, those
of Artemia as vesicular bodies. In the figures of
J urine (Hist. d. Monocl. PI. XXI. XXII.), made
for the memoir of Pr&vost , the branchiae of Chiro-
cephalus are not seen at first, but with a littLe at-
tention may be discovered. Gaede (Wiedemann'1 s
zool. Magaz. I. p. 88), Berthold (Isis, 1830, p. 689,
Taf. VII. fig. 1), and Zaddach (loc. cit. p. 11, Tab.

I. fig. 17, Tab. II. fig. 10) have regarded the large
dorsal shield of Apus as a respiratory organ,
since its lateral halves are traversed by blood-cur-
rents running close to each other (Schaeffer, loc.
cit. p. 72, Tab. I. fig. 5, b. b.), and thence passing
directly towards the anterior extremity of the
heart.

Indeed, from the vascularity and delicateness of
the under surface of this shield, one would be quite
disposed to attribute to these parts a participation
in the respiratory act.

6 For a long time, the multi-articulated, bristly,
anal feet of these small Crustacea were regarded as
branchiae, for the true branchiae are quite concealed
under the internal surface of the anterior feet.
Even after the attention had been directed to these
organs, their form was often misapprehended ; for
when these animals are a long time dying, their
branchiae are changed, from congestion, into ampul-
lae. With the Amphipoda, it is easy to distinguish
the branchial lamellae from the incubatory lamellae
at their side, for the borders of these last are bris-
tled 5 see Straus , loc. cit. p. 57, PI. IV. fig. 10, 11,
h. ( Hiella ) ; Zenker , loc. cit. p. 8 ( Gammarus ) ;
Milne Edwards, Ann. d. Sc. Nat. XX. 1830, p.
357, PI. X. fig. 7, PI. XI. fig. 1, also Ibid. III. 1835,
PI. XIV. tig. 9, and Ilist. d. Crust. III. p. 6, PI.

II. fig. 15, c., PI. XXX. fig. 1, 13, 16 (Gammarus

Phronima, Vibilia, Hyperia )• According to

Savigny's figure (Descrip, de l’Egypte, loc. cit. PI.

$ 286.

THE CRUSTACEA.

343

G. With the Isopoda, the five pairs of post-abdominal feet are nearly
always concerned exclusively in the function of respiration. The two
multi-articulate cirri of each of those feet, have been changed into plates,
which, pointing backwards, are imbricated and applied against the under
surface of the last caudal segment, which is usually very large. (7) The form
of these plates is sometimes lanceolate, sometimes discoidal or rhomboidal,
and they often differ widely in the different sexes of even the same species.
Upon the same foot, the external or anterior plate is usually leathery and
bristled on its external border ; while the internal or posterior plate is covered
with a very thin envelope, and is usually entirely glabrous. This last, there-
fore, should be regarded as the proper branchia, of which the first is only the
operculum, serving, also, often as a gyratory organ. The first case is
observed with the terrestrial Isopoda, where the branchial opercula are fixed,
rhomboidal, slightly concave, and completely cover the branchial lamellae
preserving them from desiccation.®

With most of the aquatic Isopoda, on the other hand, this apparatus is in
perpetual motion, and the branchiae are often of the same form and size as the
operculate plates. The opercula of the first pair are so large that they extend
beyond all the rest.® With the Idotheoidae, the operculate apparatus has
an entirely peculiar structure. The two feet of the last caudal segment
are developed into two valves which move laterally like the two folds of a
door, and can open and close the branchial cavity, which is provided with
five pairs of double plates. (10> The branchial apparatus of the Bopyrina
differs, in many respects, from that of the other Isopoda. With some
species, it is reduced to four or five pairs of simple, superposed plates, with-
out any accessory organ ; while with others, there are four to six branchiae
which, as more or less deeply fissured cordiform plates, or as long and

XI. fig. 42. 4'U) of Amphithoe Jilosa , this animal
has, beside the ten round branchial lamellae, a sixth
and rudimentary pair on the two posterior feet.*

I For the respiratory organs of the Isopoda, see
especially Duvernoy and Lereboullet , Ann. d.
Sc. Nat. XV. 1841, p. 177, PI. VI.

8 With the terrestrial Isopoda, the branchial
apparatus is somewhat abortive, for true branchiae
are wanting beneath the two anterior pairs of oper-
cula, and those back of the three posterior pairs
are very small and delicate ; see Treviranus ,
Verm. Schrift. I. p. 62, Taf. VI. VIII. IX. (Por-
cellio) ; Savigny , Descript, de l’figypte, loc.
cit. PI. XII. fig. 7 ( Lygia ), and PI. XIII. ( Tylos ,
Porcellio and Armadi/lidium ) ; Brandt , Mediz.
Zool. II. Taf. XV. tig. 35—37 (Porcellio), and Lere-
boullet, loc. cit. p. 118, PI. IV. fig. 17, PI. V. fig.
18-22 (Lygidium). This abortion of the bran-
chiae is compensated with some Oniscidae by the
existence of lung-like organs. (See below, § 287.)

9 Asellus has two very large, common, anterior

* [ § 286, note 6.] Leydig (loc. cit. Siebold
and Kolliker's Zeitsch. III. p. 289) does not admit
that the red pouches, above-mentioned with Apus ,
are of a respiratory character, at least with Arte-
mia and Branchipus , where he has examined their
histological composition. In this connection it may
be mentioned that this observer has found on each

branchial opercula ; but the branchial apparatus,
moreover, is composed of only three pairs of plates
on each side ( Treviranus , Verm. Schrift. I. p. 75,
Taf. X. XII.), while with Sphaeroma , Cymothoa ,
and allied genera, there are five pairs on each side
(Savigny, loc. cit. PI. XI. XII.).

With some species of Sphaeroma , Cymodocea ,
Nesea , and Amphoroidea , the branchial plates of
the last two pairs of branchiae, have numerous
transverse plicae, which connect these Sphaeroma-
toda with the Poecilopoda (Duvernoy and Lere-
boullet, loc. cit. p. 215, PI. VI. fig. 15-23, and
Milne Edwards , Hist. d. Crust. III. p. 223, PI.
XXXII. fig. 9). With Serolis , the branchial struc-
ture is quite different, the fourth and fifth pairs
of feet being changed into broad branchial plates
(Milne Edwards , Arch, du Mus. d’ Hist. Nat. II.
p. 21, PI. II. fig. 1-6).

1<> See Rathke , loc. cit. p. 115, Taf. IV. and
Milne Edwards , Hist. d. Crust. PI. X. fig. 6, 7
(Idothea).

natatory foot of Branchipus , a peculiar and new
structure. This is a roundish, dark-orange-colored,
pedunculated body, situated on the under side of the
leg near the coxal joint. This body is composed of
large nucleated cells which contain a yellowish
liquid. The use of this structure is unknown.
— Ed.

TUE CRUSTACEA.

344

$ 286.

sometimes branched tubes, project considerably beyond the lateral borders
of the posterior segments of the body. U1>

7. The Poecilopoda hold a place between the Isopoda and the Deca-
poda, their branchiae being, as in the first, inserted on the abdominal feet,
and, as with many of the second, composed of numerous plates. With
Limulus, the five posterior abdominal feet, which are inserted on the second
dorsal segment, and changed, as well as the first pair of abdominal feet,
into very large plates, have upon their posterior surface numerous semi-
oval, branchial plates lying upon each other. The first pair of feet appears
to play, also, at the same time, the part of an operculate apparatus. (la)

8. The Stomapoda, with which the respiratory apparatus is most highly
developed, have numerous branchial filaments disposed pectinately on a long
stalk, and float freely in the water.

The Squillina have a similar branchial tuft on the anterior surface of
the external plate of each of the ten swimming feet, which are only the ten
post-abdominal feet of the posterior part of the body, transformed. (13)

With Thysanopoda, only, these branchial tufts are inserted at the base
of the anterior abdominal feet.(14>

9. With the Decapoda, alt the branchiae are joined together at the base
of the anterior abdominal feet and of some of the foot-jaws ; but at the
same time they are contained in a special branchial cavity, which is covered
by the lateral parts of the cephalothorax. Each of these two cavities com-
municates externally by two fissures. One of these is situated at the
under surface of the body between the lower border of the cep»halothorax
and the base of the feet ; through it the water enters the branchial cavity.
The other is upon both sides of the masticatory organs, and through it the
water is ejected. In this last, which is sometimes prolonged into a semi-
canal/15’ are several multi-articulate cirri and lamellae, which belong to
the second and third pairs of foot-jaws. (16> Their continual motion pro-
duces a regular current of water from the branchial cavity outwards. a7)
As to the number of branchiae, there are wide differences in the various
families of this order. There may be six, seven, fourteen, eighteen or even
twenty-one in the same respiratory cavity. When numerous, there are
usually two or three fixed on the four posterior foot-jaws, three or four on

11 Both sexes of Bopyrus squillae have five pairs
of small branchial plates lying over each other like
scales (RathkJ, I)e Bopyro, kc ., p. 7, Tab. I.).
This is probably true also of the males of Phryxus
hippolytes (Rflthkd, Nov. Act. Nat. Cur. XX. p.
48). The females of this same species and of
Phryxus pap:uri have four pairs of cordate, and
nearly double plates, which stand off laterally a
little from the posterior part of the body 5 see
Rathkt, Ibid. p. 46, 59, Tab. II.*, Krciyer , Naturhist.
Tidskr. III. p. 102, PI. I. II., or in Isis, 1841, p.
693, 707, Taf. II. Tab. 1, and Taf. III. Tab. 2, or
in Ann. d. Sc. Nat. XVII. 1842, p. 142, PI. VI.
With Cepon , the branchial apparatus is highly de-
veloped in that, beside the five pairs of lanceolate and
pretty long plates which project from the sides of
the tail with the males, the five abdominal and the
last caudal segment, have six pairs of long, narrow
diverging lamellae with pectinated borders. Du-
vernoy (Ann. d. Sc. Nat. XV. 1841, p. 120, PI.
IV. fig. 1-11), has described these twelve append-
ages as the principal branchiae of Cepon, while
to me, they appear to be accessory, and are,
perhaps, vortex-producing organs — the result of a
metamorphosis of the anal feet. With Jone, all
the abdominal segments have a pair of long bran-

chial tubes pointing backwards, and with the
females of this same genus, the five anterior pairs
are branched on one side. In this sex, also, the
organization of the Amphipoda appears to be re-
peated, for, from the base of the anterior feet hangs
a long riband-like band (branchia ?). See Milne
Edwards, Hist. d. Crust. III. p. 279, PI. XXXIII.
fig. 14, 15.

12 See ran der Hoeven, loc. cit. p. 19, PI. I.
fig. 10, PI. II. fig. 1, 11-15 ; and Duvernoy , Ann.
d. Sc. Nat. XV. 1841, p. 10. PI. III.

13 Sqiiilla and Squillerichlhus ; see Trevira-
nus, Beobacht. aus d. Zoot. u. Physiol, p. 22, Taf.
VI. fig. 36-39 j and Milne Edwards , Hist. d.
Crust. PI. X. fig. 4, PI. XXVII. fig. 7.

14 Milne Edwards, Ibid. PI. X. fig. 3, PI.
XXVI. fig. 6, and Ann. d. Sc. Nat. XIX. 1830, p.
453, PI. XIX.

1-3 With many Brachyura.

16 See Suckow, loc. cit. Taf. X. fig. 1, p. q., fig.
2, p. r., fig. 3, d. s. e. ( Astacus ) ; Milne Edwards ,
Hist. d. Crust. Ifi. III. fig. 8-10, i. j. ( Mala ).

17 For this mechanism of the respiratory organs
of the Decapoda, see Milne Edwards, Ann. d.
Sc. Nat. XI. 1839, p. 126, PI. III. IV.

$ 287.

THE CRUSTACEA.

345

each of the four anterior pairs of feet, and one only on the last pair.
With these Crustacea, moreover, the organs have no connection with the
movable basal joint of the feet ; but, on the other hand, most of them
are inserted on the base itself of the respiratory cavity above this joint.
Many Macrura, which have numerous branchiae, are those exclusively
which have one of these organs inserted on the coxa of the feet.(18> As
to their structure, these organs vary also very much. Usually, they have
the form of a long, acutely-pointed pyramid with a solidly-attached
base, the axis of which is formed in its whole length by a shaft trav-
ersed by an arterial and venous canal, and covered by numerous thin
lamellae or cylindrical filaments, the size of which decreases gradually
towards their apex.(19>

§ 287.

Many terrestrial Isopoda have a branchial apparatus, the organization of
which is entirely peculiar, and distinctly indicates a pulmonary respira-
tion. With Porcellio , and Armadillidium, there are four white spots on
the two anterior pairs of the branchial opercula. These spots communi-
cate with as many cavities which ramify like vessels. They are situated
between the two plates of these four opercula, and are filled with air. At
the base of each of these opercula there is a narrow opening through
which, when these cavities are compressed, the air will escape, and then the
white spots disappear. By these means, these animals are undoubtedly in

18 The branchiae are fewest with the Brachyura,
and Caridoidae •, among these last, Crangon and
Alpheus have only six in each respiratory cavity,
and Palaemon and Hippolyte seven, f/ca, also,
has only six on each side, while with the majority
of Brachyura, namely, Portunus , Grapsus ,
Thelphusa , Gecarcinus , Pisa , Maia , Cancer ,
&c., there are eighteen in all, the two anterior
pairs of which are usually only feebly developed
and belong to the two pairs of posterior foot-jaws,
while the others are in general (Maia, Cancer ,
Lupea , &c.) so aggregated at the anterior part
of the bottom of the respiratory cavity, that the
space corresponding to the last two pairs of feet
appears gill-less. The majority of the Brachyura
have fourteen branchiae on each side, and these
organs are even more numerous with various
Macrura. Thus, I have counted eighteen with
Astacus , Homarus , arid Palinurus ; two of
which, with Palinurus , and Astacus , are in con-
nection with the middle, and three with the pos-
terior foot-jaw ; while with Homarus , this last
has also three branchiae, but the second foot-
jaw has only a rudimentary one. As to the
other branchiae, there is, in these three genera,
a branchia inserted on the coxa of the four anterior
feet. Above each of these same feet are other
branchiae disposed, in couples, with Astacus , and
in threes above the fourth foot, with Homarus , and
above the second, third and fourth, with Pali-
nurus ; while above the last foot that is gill-less,
there is only a single branchia. With Nephrops ,
there are twenty branchiae on each side, and with
Sc y liar us , twenty-one. See, for the number and
disposition of those organs with the Decapoda,
Duvernou. in Cuvier's Lecons d’Anat. Comp.
VII. p. 393.

19 The various forms of the branchiae of the De-
capoda may be reduced to two types. The first,
the less common, exists with many Macrura, for
example with Scyllarus , Palinurus , Gebia , and
Homarus. The shafts of then- branchial arches

support numerous cylinders set together in a
brush-like manner. In the figures which Audouin
and Milne Edwards (Ann. d. Sc. Nat. XI. 1827,
PI. XXIX. fig. 1, PI. XXX. fig. 2, PI. XXXI.) have
given of the branchiae of Homarus , this structure
may be easily seen. With Astacus , the cylinders are
much less numerous, and disposed only on two of
the sides of the branchial shaft, — giving it a pin-
nate aspect •, and those which are inserted on the
coxae are terminated by a thin, multiplicate lamelli-
form dilation, which has completely the structure
of a branchial lamella (Suckow, loc. cit. p 59, Taf.
X. fig. 1, 2, 25, 26, Taf. XI. fig. 5, 6 ; Brandt ,
Medic. Zool. II. Taf. XI. fig. 23). With Homarus ,
and Palinurus , also, the coxae have an analogous
plate inserted close by the side of the coxal
branchia 5 but it is of a leathery consistence and
covered with numerous hairs, so that it cannot
participate in the function of respiration, but is
probably only a septum to separate the different
groups of branchiae. Aristeus , which has six-
teen branchiae on each side, differs widely from
the other Macrura in having its penniform bran-
chiae composed of a shaft from which pass oil
right and left numerous curled filaments whose
convex border is covered by tufts of very delicab-
thick-set branchial cylinders ( Duvernoy , Ann. d.
Sc. Nat. XV. 1841, p. 104, PI. V.). The second
type is formed by these branchiae to the shafts of
which adhere at right angles numerous thin some
times rhomboidal, sometimes spheroidal lamellae,
contiguous, and decreasing in size towards the apex
of the shaft. This type occurs especially with the
Brachyura, the Anomura, and with Galithea of
the Macrura •, also of the Caridoidae, with Palae -
mow, Hippolyte , Alpheus , Pcnaeus, Crangon ,
&c. ; see Audouin and Milne Edwards , Ann. d.
Sc. Nat. XI. 1827, PI. XXVI. and XI. 1839, PI.
III. fig. 1, PI. IV. fig. 1,4 (Maia, Ranina , Palae-
mon) ; also Krdyer , loc. cit. Tab. I.-V. ( Hippo -
lyte ), and Joly , loc. cit. p. 71, PI. III. fig. 24
(Caridina).

346

THE CRUSTACEA.

§ 287.

a condition to respire atmospheric air.® But with Tylos, this pulmonary
apparatus is still more highly developed ; for, under the four pairs of oper-
cula, there are, instead of simple branchial plates, oblong appendages on
which is a transverse row of aeriferous sacs having a kind of stigma on
their under surface.®

All the Myriapoda respire by true tracheae. Their blood does not
require, therefore, special organs to receive the influence of the air, for this
last is carried into every part of the body.

The stigmata for the ingress and egress of the air, are easily seen with
the Chilopoda, for they are usually surrounded with a ring of brown chi-
tine, and situated on each side of the body between the base of the feet
and the dorsal shields; they are not found, however, above all the feet,
for the segments which have them alternate more or less regularly with
those that are without them.® With the Chilognatha, the very small
stigmata are on the ventral surface. They are situated on the anterior
border of the ventral plates, from the posterior border of which arise the
feet.® The intimate structure of these tracheae, which are usually brown,
is exactly like that of those of insects.® Among the Chilognatha, the
Julidae are noticeable for the very simple character of their trachean
apparatus. Each stigma leads into a tuft of tracheae from which arise
air-canals which neither ramify nor anastomose but gradually become
smaller and smaller and surround the various organs.® With the Glo-
merina, on the contrary, the tracheae, which arise from the stigmata by
two trunks, are branched, but do not anastomose with the neighboring
branches.® Those of the Chilopoda most closely resemble those of the
Insecta, — being very ramose, and their large trunks intercommunicating
at their origin by longitudinal and transverse anastomoses, so that each
stigma can introduce air into the entire trachean system.®

1 According to Duvernoy and Lereboullet (loc.

cit. p. 231, PI. VI. fig. 14), these cavities secrete a
liquid for the moistening of the branchiae. See
upou this subject, my observations in Muller's
Arch. 1842, p. 141, note 2. ^

2 See Savigny, Descript, de l’Egypte, loc. cit.
PI. XIII. fig. l.° — l.8 } but especially Milne Ed-
wards, Institut. 1839, p. 152, and Hist. d. Crust.
III. p. 187, and his figures in the Iconograph. du
R£gne anim. Crust. PI. LXX.

3 With Lithobius , there is a stigma above the
first, third, fifth, eighth, tenth, twelfth, and four-
teenth pairs of feet ( Treviranus , Verm. Schrift. II.
p. 29, Taf. IV. fig. 7, Taf. VI. fig. 5). With Scolo-
pendra , the stigmata have a similar disposition
( Kutorga , loc. cit. p. 14).

4 See Savi, Isis, 1823, p. 219, Taf. II. fig. 9, a. a.,
and Burmeister , Ibid. 1834, p. 134, Taf. I. fig. 2,

a. a. ( Julus ). These stigmata with Julus were
entirely overlooked by Treviranus. He had re-
garded as such the orifices of a row of glands
which are situated on the sides of the segments of
the body (Verm. Schrift. II. p. 42, Taf. VIII. fig.
4, S. S.).

5 The characteristic spiral filament of the Insecta
is also not wanting here : see Kutorga , loc. cit. p.
14, Tab. II. fig. 8.

3 Straus , Consid^rat. &c. p. 307, and Burmeis-
ter, loc. cit. Taf. I. fig. 3 (Julus).

7 Brandt , in Muller's Arch. loc. cit. p. 323, Taf.
XII. fig. 4, 5 ( Glomeris ).

8 Straus , loc. cit. p. 307, and Traits d’Anat.
comp. II. p. 161 ; Treviranus , Verm. Schrift. II.
p. 30, Taf. VI. fig. 6 (Lithobius), and Muller ,
Isis, 1829, p. 551, Taf. II. fig. 1.

§§ 288, 289.

THE CRUSTACEA.

347

CHAPTER VIII.

ORGANS OF SECRETION.

I. Urinary Organs.

§ 288.

As yet, Urinary organs have not been observed with the Crustacea
except in the Myriapoda. Here, as with the Insecta, they consist of long,
small, brownish vessels, caecal, and describing many convolutions about
the stomach and intestine. These Malpighian vessels, as they have been
termed, open into the digestive canal at the boundary between the stom-
ach and intestine, and secrete as certainly as do those of the Insecta, uric
acid.(1) 2 3 With the Chilopoda, there is usually one on each side of the
pylorus ; but with the Chilognatha, there are two, which open, however,
into the intestinal canal by a common orifice. (2>

It is now undetermined whether these organs exist also in the other fam-
ilies of Crustacea. But with some Decapoda, there are certain caecal
vessels which are imperfectly known. They open into the intestine at
various points between the pylorus and rectum, and a more complete
examination may, perhaps, show them to be of a urinary nature.®

II. Organs of Special Secretions.

§ 289.

The Astacina have a very remarkable secretion commonly known as

Crabs-eyes. Ihese are a kind of

1 For the Malpighian vessels, which were for a
long time regarded as biliary canals, see further
under the anatomy of the Insecta.

2 Ramdohr , Abhandl. uber d. Yerdauungsw.
&c. p. 149, Taf. XV. fig. 1 ( Julus ) ; Treviranus ,
Verm. Schrift. loc. cit. p. 24, 44, Taf. V. fig. 4, Taf.
VIII. fig. 6 ( Lithobius and Julus), and L. Du-
four, Ann. d. Sc. Nat. loc. cit. p. 86, 96, PI. V.
fig. 1, 4 ( Lithobius and Scutigera). Scutigera
differs from the other Chilopoda in having two
pairs of urinary canals.

See also Kutorga, loc. cit. p. 6, Tab. I. fig. 2,
and Muller, Isis, 1829, p. 550, Taf. II. fig. 5
(Scolopendra) ; finally Brandt, in Muller's Arch,
loc. cit. p. 322, Taf. XII. fig. 2 {Glomeris).

3 S wammerdamm (loc. cit. p. 87, Taf. XI. fig. 3)
had already figured, with Pagurus , a pretty long
coecum opening at the posterior extremity of the
intestine. With Mala squinado , there are three
such pretty long, of which two are inserted on each
side of the pylorus, and the third a little further
behind {Milne Edwards, Hist. Nat. d. Crust. I.
p. 76, PI. IV. fig. 1, m. n.). Lund (Isis, 1829, p.
1302) lias also seen two glandular canals rolled up
in a knot, which open each side of the pylorus,
while a third entered the rectum. This last, ac-
cording to Cuvier (Lemons d’Anat. Comp. III. p.

;uli composed of carbonate of lime

678) is very common with the Macrura, Brachyura,
and Anomura, and notably with Astacus fluvia-
tilis, Homarus marinus, Cancer pagurus, Por-
tunus puber, and Cancer maenas. But although
Milne Edwards admits the same also (loc. cit. I.
p. 76), yet it does not appear to be agreed upon, for
Meckel (Syst. d. vergleich. Anat. IV. p. 161) con-
tradicts Cuvier in this respect, and declares that
he has never found this caecum either with the
Crabs or with Astacus, Scyllarus, and Palinu-
rus, but only with Pagurus, Penaeus , and
Palaemon. Duvernoy, also (Lemons d’Anat.
Comp. V. p. 228), has not observed it in the Ma-
crura just cited, nor with Galathea squa-
mifera, and Palaemon serratus , although he
perceived it with Portunus puber directly behind
the pylorus, and with Cancer pagurus, near the
rectum. Like Milne Edwards (Hist. d. Crust.
I. p. 115, PI. X fig. 2, j. ( Maia )), I must leave un-
determined the point whether or not, this glandular
mass which, with the Decapoda, is concealed under
the floor of the respiratory cavities in the bottom
of the cephalothorax, and which opens externally
by an excretory canal between this same cephalo-
thorax and the first abdominal segment, — is
really a urinary organ.

348

THE CRUSTACEA.

§ 290.

and formed in the two lateral pouches of the stomach of the Aslacus jluvi-
atilis.a) As they are not observed during the whole year, but only just
before the moulting, and as, when this process occurs, they pass from the
cast-off stomach into the cavity of the new one, it may be inferred that
they are in some way connected with the act of ecdysis, and that if the lateral
pouches of the stomach secrete from the blood the excess of calcareous
salts, it is in order that these last may be subsequently used for the for-
mation of the new shell.®

The caustic, brown fluid, which most Myriapoda, when touched, emit from
a row of oriflces situated on the sides of the segments of the body ( Fora-
mina repugnatoria), and which exhales an odor like that of chlorine, is
secreted by small, pyriform, glandular follicles, situated immediately
beneath the skin. Its use is, perhaps, for the lubrication of the articula-
tions of the segments of the body.®

In the following chapter will be mentioned many other glandular organs
connected with the genital functions.

CHAPTER IX.

ORGANS OF GENERATION.

§290.

The Crustacea reproduce by Male and Female Organs, situated in differ-
ent individuals, and have, for the most part, copulatory organs.

Nevertheless, the Cirripedia form an exception in this respect, being
hermaphrodites ; while, on the other side, many Entomostraca differ from
the general rule, in their species being almost exclusively females, which
produce, during many successive generations, individuals exclusively of the

female sex, and only at long intervals,

1 See Suckoiv, loc. cit. p. 53, Taf. X. fig. 10, 11,
e. This author is mistaken in supposing that those
green glandular bodies mentioned in connection
with the organs of hearing (§ 276), secrete the
“ Crabs-eyes.” See also Brandt , Medic. Zool. II.
p. 63, Taf. XI. fig. 8, 9, c.

2 For the nature of these crabs-eyes, see the re-
searches of Baer (Muller's Arch. 1834, p. 510) and
Oesterlen , Ibid. 1840, p. 432.

3 Treviranus (Verm. Sell rift. II. p. 42, Taf.
VIII. fig. 4,/./. fig. 5, d. e.) has regarded these
organs as respiratory with Julus , while Savi (Isis,
1823, p. 218, Taf. II. fig. 1, 13, 14, a. b.), and
Burmeister (Ibid. 1834, p. 136, Taf. I. fig. 1, a. a.)
have well perceived that they are cutaneous glands.
According to JVaga (Revue Zool. 1839, No. 3, p.
76, or in Wiesmann's Arch. 1840, II. p. 350),
Polydesmus , Platyulus , and Geophilus electri-
cus , have, upon the sides of the body, analogous
glands, out of which this last Myriapod emits a

* [ § 289, note 3.] These odoriferous glands
have been successfully studied by Leidy (Proc.
Acad. Sc. Philad. 1840, IV. p. 235) with Julus.
Here, they consist of a globular body or sac, with
an elongated conical neck, and resemble in form a

those of the male sex.(1) There is,

luminous liquid. Brandt (Recueil, &c., p. 154,
157) has observed, with Glomeris , that these fol-
licles are situated, in pairs, on the dorsal surface
of each segment of the body.*

1 This is so with the Daphnioidae, Cypridoi'dae,
and Apodidae. In the second of these groups, the
males are so rare, that these Entomostraca have
been taken for hermaphrodites, and Straus (loc.
cit. p. 52, PI. I. fig. 15) has said that if this was
really the case, he regarded as testicles two long
cylindrical problematical bodies which he had ob-
served with all the females of Cypris. In the
genus Apus , no individuals which can with cer-
tainty be regarded as males, have been found.
Berthold (Isis, 1830, p. 693) has taken the
red ampullae found with these Crustacea for
testicles *, but, as I have already remarked, these
ampullae are only branchial lamellae filled with
blood during the dying of the animal. (See § 286,
pote 5.)

florence flask with the mouth drawn to a point.
This sac is composed of a basement membrane
lined with a single layer of secreting cells. The
neck of the glands has muscular bands. — Ed.

9

§ 290.

THE CRUSTACEA.

349

probably,* some relation between this remarkable mode of generation and the
fact that some females' lay two kinds of eggs, one of which is developed
spontaneously, that is, without the influence of sperm, while the other re-
quires to be fecundated.®

The structure and disposition of the genital organs is so different in the
various divisions of Crustacea, that it is difficult to make any general state-
ment about them. Usually, there is a complete duplication of these organs,
internal and external, with both sexes. With the females, there is nearly
always, right and left, a longer or shorter, rarely-branched, ovarian tube.
This is succeeded by a narrow oviduct, usually long, and often flexuous. This
last continues into a large vagina, which opens at very different points on
the ventral surface, sometimes quite in front, sometimes near the middle,
or at the posterior extremity. It is rare that this vagina has a Receptacu-
lum seminis ; but, more commonly, the females have special glandular
canals annexed to the genital orifice. The product of these last is a viscous
mucus, which hardens in water, and serves to envelop the eggs-, and to glue
them together. The eggs, thus bound together in chaplets or clusters,
remain glued to the parts neighboring the genital orifice, or to the post-
abdominal feet, and are borne about by the females, until the embryos
are fully developed. With other females, where these organs are wanting,
they are replaced by a special pouch ( Marsupium ) situated, usually, at the
inferior surface of the thorax. In this pouch the eggs are deposited and
remain until their embryos are completely developed.

With the males, the internal genital organs are disposed in a similar
manner, and often have the same form as those of the females. A
careful examination is, therefore, necessary, to perceive their distinctive
character. Moreover, they open, also, at the most varied points of the
body. In many species, there are, near the genital orifices, copulatory
organs in the form of stylets, or canaliculi, which serve to transfer the
sperm into the female organs. With others, the antennae, or some of the
feet, are provided with a kind of hook, or pincers, with which they seize
and retain the females during copulation. Sometimes the internal organs
of the left communicate, by anastomoses, with those of the right side, or, in
the place of two lateral genital openings, there is only one, situated on the
median line. With many species, the genital organs, internal and external,
are simple, and placed in the axis of the body; but it is rarely observed,
that the oviducts and deferent canals are single where the ovaries or the
testicles are double, or that there are two genital openings for single in-
ternal organs.

The Eggs of the Crustacea are usually of either a lively green, yellow,
or violet color. They are always spherical, and composed of a dense
chorion, containing a vitellus, which surrounds a germinative vesicle, with
one or more nuclei. The vitellus is composed of numerous oil-globules,
which are held together by a clear, albuminous liquid, and give the egg its
peculiar color.®

The sperm is white and sometimes opalescent. The spermatic particles
are of very varied and remarkable forms. Nearly always, they are

*

2 This phenomenon is undoubtedly analogous to mal. Crust, generat., 1844, and his Bemerkungen in

that of the alternation of generation, which is so Fr<oriep\s neue Notiz. XXIV. 1842, p. 181 *, Erdl ,
general with the other lower animals. Entwickelung d. Ilummereies, p. 13 *5 and especially

3 For the eggs of Crustacea, see Rathki , De Ani- tVagner, Prodromus, &o., p. 8, Tab. I. fig. 12-17.

30

3 HO

THE CRUSTACEA. § 290.

stiff and motionless, and may be arranged under tbe following principal
types.

1. With the Cyclopidae, and Chilognatha, the spermatic particles, which
are developed in cells, retain their cell-form to their perfect state, without
any trace of processes or appendages/4*

2. With the Decapoda, they are likewise nearly always of a granular or
cell form, but have small, filiform, sac-like processes; sometimes they are
divided into two portions by a constriction. (5)

3. With the Mysina, Amphipoda, and Isopoda, they have the form
of very long threads, pointed at both extremities, or with a cylindrical
incrassation at one of them. They are motionless, and, upon the addition
of water, do not roll up in a loop-like manner.®

4. With the Cirripedia, and Chilopoda, they are capillary, very lively,
and, from contact with water, become entangled, forming loops and
rings. (7>

4 With Cyclopsina castor , the spermatic parti-
cles are small, finely-granular, oval corpuscles (see
my Beitr. zur Naturg. d. wirbellosen Th. p. 41, Taf.
II. lig. 41-13 c., or Ann. d. Sc. Nat. XIV. 1840,
p. 30, PI. V. B.). As to the other Entomostraca,
we have not yet sufficient data to say anything in
general. But the form observed with Cyclopsina
castor cannot be regarded as a typical one with
these animals, for Wagner ( Wiegmann's Arch.
1836, I. p. 369) has observed large, filiform, flexu-
ous, spermatic particles with Cypris. I, myself,
have found those of Daphnia rectirostris to con-
sist of a long, semi-circular body, which became
motionless and disappeared by bursting on the ad-
dition of water. Stein (. Muller's Arch. 1842, p.
263, Taf. XIY. fig. 37, 40) has rightly figured those
of Glomeris as fusiform cells 5 but he was less exact
with those of Julus and Polydesmus , in describing
them as small transparent vesicles (Ibid. fig. 36, 39 .)

With Julus subulosus , they look exactly like
very short cylinders containing a very distinct,
round nucleus. With Julus hispidus , they are
of the same form, but are not nucleated; while with
Julus terrestris , they are conical and nucleated
(see my notice in Muller's Arch. 1843, p. 13).
Those of the Siphonostoma are, also, of a celloid
form ; see Frey and Leuckart , Beitr. loc. cit. p.
135, Taf. II. fig. 21 ( Caligus ).

5 Henle ( Muller's Arch. 1835, p. 603, Taf. XIV.
fig. 12) and myself (Ibid. 1836, p. 26, Taf. III.
fig. 23, 24) first called attention to the singular
form of the spermatic particles of the common
craw fish ; but, subsequently, Kblliker (Beitr. &c.
1841, p. 7, Taf. II. III. and in the Schweizerisch.
Denkschrift. f. d. gesammt. Naturw. VIII. 1846,
p. 26, Taf. II.) has shown that those of the most di-
verse species of Brachyura, Anomura, and Macru-

ra, are motionless, radiated cells , one part of
which is separated by a constriction, and prolonged
sometimes into a kind of peduncle ; the rays
are often only three or four in number, and the
cells themselves are sometimes conical or cylindri-
cal. The most simple of these spermatic particles
are observed with Crangon vulgaris , and Palae-
mon squilla ; and, according to my own observa-
tions, consist only of flattened cells with a short
pointed process.

<> Simple capilliform spermatic particles are found
with My sis , Oniscus , Porcellio , Idothea , and
Gammarus ; see my researches in Muller's Arch.
1836, p. 27, Taf. III. fig. 19, 20, and Ibid. 1837,
p. 433 ; also Kolliker , Beitr. loc. cit. p. 15. This
last naturalist (Beitr. &c. p. 14, Taf. III. fig. 28,
29) has stated that the long capillary, but motion-
less spermatic particles of Iphimedia obesa and
Hyperia rnedusarum are terminated by a cylin-
drical and slightly flexuous incrassation. I have
found those of Asellus aquaticus to be similar,
but the cylindrical extremities were straight.

7 The spermatic particles of the Cirripedia, which
are simply capillary and very active when fully de-
veloped, have been observed by me ( Muller's
Arch. 1836, p. 29), with Balanus pusillus , and
by Kblliker (Beitr. p. 16, Taf. III. fig. 30, and
Schweiz. Denks. loc. cit. p. 33) with many other
species of Balanus , and with Chthamalus, Lepas ,
and Pollicipes. Those of Lithobius and Geophi-
lus present a remarkable aspect from their extreme
activity, and may well be recommended for study
from their siz e (Stein, in Muller's Arch. 1842, p.
250, Taf. XIII. XIV. fig. 19-33). Treviranus
(Verm. Schrift. II. p. 26, Taf. VI. fig. 2, 3) has
taken those of Scolopendra , which are bound to-
gether in a long white cord, for a Helminth.*

* [ § 290, note 7.] The spermatic particles of
the Crustacea are the most remarkable of any in
the whole animal kingdom. The strange, bizarre
forms, here observed, have led to singular views as
to their development and character. The recent
researches of Kblliker have done much to clear up
this intricate subject, and these researches have
been continued by Wagner and Leuckart (Art.
Semen , Cyclop. Anat. and Physiol.). The most
singular of these particles, as is well known, are those
belonging to the higher forms of this class. The de-
velopment and nature of these I have recently stud-

ied, and with results quite different from those of the
authors just mentioned. My observations were made
on those of Pagurus , Pilumnus and Astacus.
Here, the development occurs in special cells like that
of those of other animals, and the particle, howev-
er singular its form, is the transformed nucleus of
these cells. The spine-like processes lie reverted
(m the body of the particle when this last is in the
special cell, but become erect and prominent when
the particle escapes. The body of the particle,
therefore, is solid, and not hollow and nucleated,
as has been supposed (see Kblliker and his

$ 291.

THE CRUSTACEA.

351

With very many Crustacea, the sperm, at its emission, is contained in
capsules ( Spermatopkores ).

I. Hermaphrodite Crustacea.

§ 291.

With the Cirripedia, the male and female genital organs are quite re-
moved from each other. With the Lepadea, the ovaries are lodged in the
upper extremity of the peduncle and in the midst of the spongy substance,
filling its cavity.® They consist of ramified caeca, while with the Balano-
odea, the ovarian follicles are situated between the lamellae of the mantle.®
With the Lepadea, the canal which extends from the lower extremity of
the shell into the peduncle and communicates by a narrow opening with the
cavity of the mantle, may properly be regarded as an oviduct.® But new
researches are required to show by what means the eggs of the Balanodea
reach this same cavity, for, as is the case with the Lepadea, they remain
there until the embryos are fully formed. These eggs, of a blue or yellow
color, are always intimately glued together, and form, after the laying, a
large sheet or layer which, with the Balanodea, is applied to the internal
surface of the mantle, and often retained there by the branchial lamellae ;(4)
while with the Lepadea, it covers, bonnet-like, the rounded portion of the
body.

The Testicles are composed of numerous ramified follicles spread out be-
tween the skin and the two sides of the digestive canal. They join from
the right and left into two very long and tubular Vasa deferentia which
accompany, serpentinely, the alimentary canal to the anus, and then blend
together, forming a more narrow Ductus ejaculatorius. As this last trav-
erses the whole tail and opens at its extremity, it has been usually regard-

1 Burmeister (Beitr. p. 46), and Wagner ( Mul-
ler's Arch. 1834, p. 469, Taf. VIII. fig. 10), were
the first to notice the ovarian follicles of the foot of
the Lepadea, the first with Otion , the second witli
Lepas. Martin St. Ange (loc. cit. p. 20, PI. I.
fig. 10, 11) has verified this fact with this last ge-
nus. I have found them also in the foot of Cine -
ras, and I will remark that in the remaining spongy
substance of this foot, there are other round nucle-
ated bodies which appear to be solid concretions,
and should n >t be confounded with the germs.

2 The ovaries of the Balanodea are more difficult
of study than those of the Lepadea, probably be-

figures). The nuclear appearance is due, some-
times to a depression in the body (as with Astacus ),
sometimes to a plastic membrane lying about one of
the spinous processes (as with Pilumnus ), all
made prominent by the refraction of the light ; see
my researches in the Proceed. Boston Soc. Nat.
Hist. IV. p. 258.

In regard to the spermatic particles of the Ento-
mostraca, I have examined those of Cypris, Cy-
clops, and Daphnia. They are developed, as usual,
in special cells — are exceedingly minute, and in
form closelj’- resemble those of the Araneae •, consist-
ing of an arcuate rod to which is attached a short
but very delicate tail. My results, therefore, do
not agree with those above-mentioned.

cause they are scattered in the walls of the mantle,
and consequently scarcely visible, especially when
empty. It is undoubtedly on this account that
Poli (Testae, utriusq. Sicil. &c. I. p. 19, 28, Tab.
IV. fig. 13, x. x. Tab. V. fig. 13, 15) has taken foi
ovaries, with & Ba/anus , the testicular follicles, al-
though he distinctly saw and has figured the ovari-
an follicles in another species of this same genus.

3 This canal, regarded as an oviduct by Wagner
(loc. cit.), had already been mentioned by Cuvier
(Mem. loc. cit. p. 4, fig. 4).

4 With Balan'ts , the layers of eggs form usually
two large discs ( Poh\ loc. cit. Tab. IV. fig. 18, c. c.).

The whole subject of the spermatic particles ot
the Crustacea is sadly deficient in well-authenti-
cated observations, and particles and cell-like forms
are constantly described as spermatic particles,
which, according to all the laws of Spermatology
as yet known, cannot be such. It should be re-
membered that the spermatic particle is never a
cell, but is the metamorphosed nucleus of a cell ; it
is, therefore, always a more or less solid corpuscle
(whatever be its form, &c.), and to which, moreover,
there may be attached one or more appendages
— Ed.

352

THE CRUSTACEA.

§ 292.

ed as a Penis.<5) The length and mobility of this tail is such that it can be
used, with the Cirripedia, as a copulatory organ, and, being brought in
contact with the orifice of the oviducts, which is situated on the mantle,
self-impregnation may thus take place.*

II. Female Crustacea.

§ 292.

The female genital organs of the Siphonostoma and Lophyropoda consist
nearly always of two long and sometimes flexuous ovarian pouches, situated
on both sides of the digestive canal. The oviducts pass backwards and
terminate on both sides of the end of the body by separate orifices, or by
a single genital opening on the median line. With those species whose
body has a tail, these orifices are not situated like the anus, at its extrem-
ity, but at its base. Very often, they serve as the outlets of the excre-
tory ducts of two caecal organs which secrete a viscous substance by which
the eggs are glued together in clusters or chaplets. (1> Not unfrequently,
there are hook-like or capsular appendages near the genital openings, for
the retention of these clusters.® But these are wanting with the Daphni-
oidae, there being in their place an incubating cavity, situated between the

5 Cuvier (M6m. loc. cit. p. 9, fig. 8) has taken,
with Lepas , the testicles for the ovaries, and the
Vasa deferentia for the testicles. This error could
not be rectified until the discovery of the true
ovaries (see Burmeister , Beitr. loc. cit. p. 33,
Taf. II. fig. 16 5 IVagner , in Muller's Arch. loc.
cit. p. 469, Taf. VIII. fig. 8 ; and Martin St. Ange ,
loc. cit. p. 21, PI. II. Lepas). It is more singular
to see Goodsir (Edinb. New Philos. Jour. 1843, Ju-
ly, p. 88, PI. III. IV. or Ann. d. Sc. Nat. I. 1844,
p. 107, PI. XV. C. or Froriep's neue Notiz. No.
651, 1844, p. 193), endeavor to confuse this ques-
tion by declaring the hermaphrodite animals of
Balanus to be females which carry, in the cavity of
their mantle, dwarfish and abortively-formed males.
Very probably those so-called males are parasitic
Crustacea, as Kulliker (Schweiz. Denks. loc. cit. p.
33) has supposed.

1 TlfS^female genital organs are completely double
with the Penellina, the Lernaeodea, the Ergasilina
and the Caligina j see N ordmann , loc. cit. p. 6,
Taf. I. fig. 4, Taf. V. fig. 7, Taf. VI. fig. 10 (. Lam -
proglena , Achtheres and Peniculus) ; Goodsir ,

* [ § 291, end.] That the Cirripedia are not uni-
versally hermaphrodites, was first discovered by
Goodsir (Ed. New Phil. Jour. XXXV. p. 88), up-
on Balanus balaenoides. The male is very small,
and it is not strange that it before eluded observa-
tion.

Darwin has made some researches, lately, with
a similar result in some respects. Exceptions to
the rule were found by this naturalist in the genera
Ibla and Scalpellum. With Ibla , the males lie
within the sac of the female, and have an elongated
body with a pedicle below. He ha3 also observed
that, with these genera, there are both females
and hermaphrodites *, and in some hermaphrodites,
males have been observed so similar in general

Edinb. New Philos. Jour. July, 1842, p. 178, or Ann.
d. Sc. Nat. XVIII. 1842, p. 181 ; Krdijer , Naturh.
Tidskr. I. PI. VI. or Isis, 1841, p. 194, Taf. I.
Tab. VI. fig. 4, C. (Caligus) ; and Rathke , Nov.
Act. Nat. Cur. XIX. p. 145, Tab. XVII. fig. 2 (Di-
chelestium). This last-mentioned author was the
first to notice the organs which, in various Crustacea,
secrete the viscous matter mehtioned in the text. He
found them highly developed with the Nicothoe
(loc. cit. XX. p. 106), where they extend, with the
ovaries, even into the wing-like appendages of this
parasite. The ovarian follicles of Chondr acanthus,
which are multiramose, differ very much from the
usual form ( Rathke , Ibid. XX. p. 123, Tab. V. fig.
18). With the Cyclopidae, there is only a single
genital opening, although the ovaries and the or-
gans secreting the viscous matter, are double. But
with Argulus , the female genital organs are the
most simple, consisting only of a single ovarian
tube, opening at the base of the tail (J urine, loc.
cit. p. 448, PI. XXVI. fig. 3).f
^ Nordmann, loc. cit. p. 8, Taf. II. fig. 6 (Er-
gasilus).

character to those of Ibla, that he considers them
to be true males of the species with which they are
connected. Being thus supernumeraries, he has
termed them complemental males. As spermatic
particles were distinctly observed in them, their
male nature is clear, but it would not appear
equally clear that they really belong to the genus
and species with which they are connected. Facts
so singular require further research. See Darwin,
Monogr. &c. loc. cit. p. 207, 231. — Ed.

t [ § 292, note 1.] For further details on the fe-
male genital organs of Argulus, with illustrations,
see Leydig , loc. cit. in Siebold and Kolliker's
Zeitsch. II. p. 339, Taf. XIX. fig. 5, a. Taf. XX.
fig. 8, 10. — En.

§ 292.

THE CRUSTACEA.

353

shell and the posterior part of the hack.® The females of Daphnia have,
beside those eggs which are rapidly developed in this cavity, another kind
known as the hibernating eggs, and in which no germinative vesicle is
observed. They are always found in couples in a thickened, saddle-like por-
tion of the shell of the animal, which is often of a black color, and separ-
ated from the shell by a kind of nloulting. Thus enveloped in a bivalved
capsule, they are protected against the severities of the winter.®

Among the Phyllopoda, the Apodidae are distinguished for the very large,
multiramose, ovarian follicles which border the two oviducts on every side ;
these last are straight and large, and situated on the side of the digestive
canal. With Apus, each of them sends olf, at about its middle, a short,
excretory canal, to the eleventh pair of feet, in which there are two alveo-
late receptacles with covers for the reception of the eggs.® With the
Branchiopoda, the ovaries consist of two straight coeca, situated in the
tail, on each side of the intestine. Their upper extremity, beneath the last
pair of feet, passes into an elongated receptacle. These two receptacles,
separated from each other only by a thin partition, have a narrow outlet at
their posterior extremity, and form, under the base of the tail, a kind of
oblong tumor, into which the hard and granular eggs are constantly cast
from the contractions of special muscular bands.® There are, moreover,
on the sides of the body above the last pair of feet, two oblique horny
plates, which the males, during copulation, seize with their cephalic pincers.

With the Poeeilopoda, the cephalothorax contains two ramified ovaries,

3 See Straus , M6m. sur les Daphnia, loc. cit. p.
413, PI. XXIX. and Jurine , Hist. d. Monocl. PI.
YHI.-XVI. The genera Argulus and Cypris dif-
fer, moreover, from the other Entomostraca, in
that they do not bear about their eggs after laying,
but deposit them on foreigu bodies ; see Jurine ,
M£m. sur l’Argule, loc. cit. p. 451, and Straus ,
Mem. sur les Cypris, loc. cit. p. 54.

4 The formation of the saddle, which is intimate-
ly connected with the deposition of the hibernating
eggs, has been called by Jurine the Maladie de la
selle. But it has been before observed by Muller
(Entomostr. p. 84, Tab. XI. fig. 9-11, Tab. XII.
fig. 5), and by Ramdohr (loc. cit. p. 28). See, also,
Straus , loc. cit. p. 415, PI. XXIX. fig. 16, 17, and
Jurine , Hist. d. Monocl. p. 120, PI. XI. fig. 1, 4.*

5 Sec Schaeffer , Der krebsartige Kiefenfuss, p.
79, Taf. IV. fig. 2-7, and Zaddach , loc. cit. p. 51,

* [ § 292, note 4.] Recent investigations upon the
economy and development of the Crustacea indi-
cate that the phenomena above-mentioned, of the
reproduction by means of a second kind of eggs
(so-called), is far from being limited to a few of
these animals. Indeed, it is probable that all or
most of the Entomostraca reproduce by this mode.
As mentioned on a preceding page, these phenome-
na do not appear to me to belong to true oviparous
reproduction, but must be considered as a kind of
internal gemmiparity. The so-called winter-eggs
are, therefore, not eggs, but buds (gemn\ae) — a
view which is borne out by their composition, —
there being no germinative vesicle and dot. This
subject will be discussed with some detail below (note
under §355) when speaking of the Aphides — animals
with which I have traced these phenomena with
some care. For many interesting details on this

30^

Tab. I. (Apus). With Limnadia , and Isaura , a
special receptacle is wanting *, the eggs are attached
to the feet probably by the aid of their hairy
external envelope •, see Brongniart , loc. cit. p. 88 •,
Straus, Mus. Senckenb. loc. cit. Taf. VII. fig. 16,
aud Joly, loc. cit. p. 308, PI. IX. A.f
6 See Prevost, in Jurine's Hist. d. Monocles, p.
228, PI. XX. fig. 1, 10 (Chirocephalus). This au-
thor erroneously declares, moreover (loc. cit. p.
207), that the females of this animal have, also, at
the end of the tail, openings into which the sperm is
received during coition. See also Joly (loc. cit. p.
240, PI. VII. fig. 12, PI. VIII. fig. 4), who regards
the receptacles of the eggs, with Artemia, as the
ovaries. The eggs with a solid, granular shell, of
Branchipus , have been pretty distinctly figured by
Schaeffer (Der fischform. Kiefenfuss, fig. 14).

subject, see Litvin, Die Branchiopoden der Dan-
zigcr Gegend, 1848, p. 11. et seq.; Baird, Brit.
Entomostr. &c. loc. cit. passim 5 Zenker, Physiol-
ogische Bemerkungen fiber die Daphnoidae, in
Muller's Arch. 1851, p. 112 •, Ley dig , Ueber Ar-
temia salina und Branchipus stagnalis, in Siebold
and Kolliker's Zeitsch. III. 1851, p. 297. — Ed.

t [ § 292, note 5.] For the female genital organs
of Artemia and Branchipus, see Lcydig (loc. cit.
Siebold and Kolliker's Zeitsch. III. p. 300). Jo-
ly, it would appear, did not observe the ovaries of
Artemia, but has described the egg-capsules as
such. The real ovaries here consist of sacs or
pouches, lying near the dorsal surface of the abdo-
men, and extending to the second abdominal ring •,
these ovarian sacs pass into a vesiculiform dilata-
tion, which has non-muscular walls, and corre-
sponds to a uterus. — Ed.

354 THE CRUSTACEA. § 292.

the large oviducts ‘of which open at the base of the first pair of feet, near
the median line of the body.*71

With the Laemodipoda, Isopoda, Amphipoda, and Mysina, there are
two simple ovarian tubes wound about the digestive canal ; these oviducts
are sometimes terminal, sometimes lateral. The two vulvae are usually
situated on the internal side of the fifth pair of feet.® The eggs, after
laying, are always deposited in an incubating pouch, situated beneath the
anterior extremity of the body, and the walls of which are formed in part
by from two to five pairs of imbricated, and often concavo-convex lamel-
lae.® These last are generally bristled on their borders, and are chiefly
developed at the epoch of procreation, after which they disappear.*®

The ovaries of the Squillina differ remarkably from those of the other
higher Crustacea. They consist of numerous, ramified lobes, filling the lat-
eral portions of the posterior abdominal segments, and the digitations of
which extend even into the last and flattened caudal segment. All these
divisions of each ovary join in a large, long tube, which surrounds the
digestive canal. The portion of the ovary contained in the three segments
to which are attached the ambulatory feet, sends towards the ventral sur-
face, three branches, which join, upon the median line beneath the abdomi-
nal cord, with those of the opposite side, and form, in the middle of each of
these three segments, a round sinus. These sinuses are connected by longi-
tudinal anastomoses, and the anterior one is prolonged into a common
papillary vulva, situated in the middle of the first abdominal segment
beneath a horny process. (U>

7 Fan der Hoeven, loc. cit. p. 21, PI. II. fig. 15,
PI. III. fig. 1 ( Limulus ).

8 There are two ovarian tubes, each continuous
posteriorly into a short oviduct with Cyamus
( Roussel de Vauzime, loc. cit. p. 253, PI. IX. fig.
19), with Aega (RathkS, Nov. Act. Nat. Cur. XX.
p. 32, Tab. VI. fig. 17), and with My sis (Frey,
loc. cit. p. 25). The two oviducts meet in a com-
mon vulva in front of the anus with Bopyrus and
Phryxus (. Rathki , De Bopyro, &c., p. 19, Tab. I.
fig. 7, and Nov. Act. Nat. Cur. XX. p. 47). With
the Asellina, the ovarian tubes are coecal at both
of their extremities ; the oviducts pass otT laterally
and open in the articulation of the fifth and sixth
segment of the body ( Brandt , Mediz. Zool. II. p.
76, Taf. XV. fig. 32). I have observed an analo-
gous structure in the genital organs of ldothea
( Muller's Arch. 1837, p. 434). With Caprella ,
the ovarian tubes are coecal in the same way, but
they interanastomose by two pairs of short, trans-
versal oviducts (Goodsir, Ediub. New Philos. Jour.
July, 1842, p. 184, PI. III. fig. 2). This author
adds, contrary to all analogy, that these oviducts
terminate in two vulvae situated one behind the
other on the middle of the belly.

9 The incubating sac of Cyamus and Caprella
is composed of four lamellae situated back of the
branchiae upon the two footless segments of the
body ( Roussel de Vauztme, loc. cit. p. 249, PI.
VIII. fig. 3, and Goodsir , loc. cit. p. 105, PI. III.
fig. 3, 10). With My sis, this cavity contains also
only four lamellae covered with stiff bristles and
attached to the coxae of the last two pairs of feet
(Muller, Zool. Danic. Tab. LXVI. fig. 1, 2 ; Milne
Edwards, Hist. d. Crust. PI. XXVI. fig. 8, d.;
and RathlU , in Wiegmann's Arch. 1839, I. p.
199). With Nerocila , there are also four large
lamellae arising from the coxae of the sixth and
seventh pairs of feet. With ldothea, the Aselli-
na and the Gammarina, on the other hand, the
five anterior segments of the body have as many

pairs of ventral lamellae of this kind. With Gam-
marus, the borders of these ten lamellae are cov-
ered with long bristles (Zenker, loc. cit. p. 8, fig.
N. b.). With Cymothoa , the coxae of the first six
pairs of feet have a semilunar lamella (Milne
Edwards, Ann. d. Sc. Nat. III. 1835, PI. XIV.
fig. 2, and Cyclop, loc. cit. p. 784. fig. 436). The
same is true of Anilocra, judging from Savigny's
figure (loc. cit. Crust. PI. XI. fig. 10'2). With
Bopyrus, and Phryxus, the incubating sac con-
tains six pairs of lamellae which, in the first of
these genera, are not wholly superposed (Rathkd,
De Bopyro, &c., p. 6, Tab. I. fig. 5, and Nov. Act.
Nat. Cur. XX. p. 44, Tab. II. fig. 12). The sixth
or anterior pair of these lamellae is wanting with
Cepon (Duvernoy, Ann. d. Sc. Nat. XV. 120, PI.
IV. fig. 2),‘ but with the Bopyrina in question, is
singularly attached to the head. According to
Treviranus (Verm. Schrift. I. p. 61, Taf. IX. fig.
52), there are at the bottom of this sac with
Oniscidae, four short conical processes which se-
crete a yellowish fluid ; but Brandt (loc. cit. II.
p. 72, Taf. XII. fig. 2, Taf. XV. fig. 33) was una-
ble to find them, while Rathki (loc. cit.) has been
led to regard as secreting organs also, two fila-
ments which, with Mysis, are attached to the ven-
tral wall, and stretch into the incubating sac.

10 This origin and disappearance of the incubat-
ing lamellae I have seen very distinctly with Ido-
thea entomon (Muller's Arch. 1837, p. 435). The
females of Cyamus which Muller (Zool. Danic.
Tab. CXIX. fig. 16), and Treviranus (Verm.
Schrift. II. Taf. I. fig. 2). have figured, appear to
have tysen individuals whose incubating sac was
not then fully developed.

11 The ovaries of Squilla are so intimately blend-
ed in part with the liver, that they may be easi-
ly confounded with that organ. It is on this
account that Duvernoy' s figure (Ann. d. Sc. Nat.
VI. 1836, p. 248, PI. XV. and VIII. 1837, p. 42,
PI. II.) of this organ with this same animal, is not

§ 292.

THE CRUSTACEA.

355

With the Brachyura, the cephalothorax contains four long ovarian tubes,
two anterior, and two posterior. The first wind outwardly over the liver,
and are anastomosed by a short transverse canal ; while the second are
straight, lie close to each other, and cover the anterior part of the intes-
tine. The anterior and posterior tubes of each side unite in a short
vagina, and, at their point of junction, open into a pyriform sac, which has
been regarded by some as a Bursa copulatrix, and by others as a gland
secreting the viscous substance which envelops the eggs, but which, upon a
more careful examination of its contents, will be found to be a Rccepta-
culum seminis .(12) The two vaginae open near the ventral median line in the
segment which bears the third pair of feet.(13) With the other Decapoda, —
the Anomura and the Macrura, — these sacs, just mentioned, are wanting,
while the ovaries themselves are disposed, in general, like those of the
Brachyura. (14> But the genera Pagurus and Astacus, alone, form an
exception in this respect. In the first, the two ovaries with their oviducts
lie concealed principally beneath the dorsal surface of the tail ; while in
the second, they are aggregated in a trilobed mass in the pyloric region,
from which pass off two short oviducts.05* The female genital openings
are situated, with the Anomura, as with nearly all the Macrura, in the
coxal joints of the third pair of feet.(16>

With the females of all the Decapoda, the feet of all the caudal seg-
ments are highly developed and very hairy. They serve to support the
eggs which are glued together in clusters by a viscid substance which
hardens in water ; these clusters are attached to the bristles or hairs of
these feet. But with the Brachyura, and Anomura, these eggs have an
additional protection in the tail, which is folded against the body.07*

The Chilognatha have only a single long and large ovarian tube, pro-
vided with two short oviducts which are narrower, and open externally at
two squamous bodies situated on the under surface of the third segment of
the body. These two bodies contain two short caeca one of which is
dilated at its base into a vesicle, and each pair opens by common orifice
in the vulva. They represent a Receptaculum seminis .(18> With the

perfectly clear. This naturalist has, moreover, re-
garded a large part of the ovaries as venous sinus-
es, and the white eggs which they contain as coagu-
lated blood. In order to have a general. idea of the
disposition of the female genital organs with these
animals, it is only necessary to cast a glance over
Delle Ckiaje's figure (Descriz. &c. Tav. LXXXVI.
fig. 4, b. g. g.); it is true that he has represented
them as testicles, but they are perfectly exhibited,
with the exception, however, of the anterior por-
tion.

See Cavolini , loc. cit. p. 138, Taf. II. fig. 3
(Grapsus) ; Milne Edwards , Hist. d. Crust. I. p.
170, PI. XII. fig. 12, and Cyclop, loc. cit. p. 784,
fig. 434 •, Cams , Erlauterungstaf. loc. cit. Heft. Y.
p. 7, Taf. III. fig. 7, and Erdl, Entwickel. d.
Hummereies, p. 11 ( Ma'ia ).

•3 Cavolini , loc. cit. Taf. II. fig. 2, a. (Grap-
sus); Milne Edwards , Hist. d. Crust. PI. III.
fig. 4, i. ; and Cams , loc. cit. Taf. III. fig. 8, b.
(Mata).

14 Milne Edwards , Hist. d. Crust. I. p. 171,
and Duvernoy , in Cuvier's Lec.ons, &c., loc. cit.
VIII. p. 349.

15 The internal female genital organs of the craw-
fish are represented in Roesel , loc. cit. Taf. LX.
fig. 24, 25 *, in Suckow , loc. cit. Taf. X. fig. 16 ;
and in Brandt and Ralzeburg's Mediz. Zool. II.
Taf. XI. fig. 15.

16 The two vulvae of the crawfish may be seen
in the figures already cited. For those of the
Anomura, which, except with Pagurus , are cov-
ered by the tail curved in front ; see Milne Ed-
wards, Hist. d. Crust. III. p. 172, PI. XXI. fig ei,
18 (Dromia and Remipes ), and Arch, du Mus. 1 1.
PI. XXVI. fig. 1, e. KLithodes). But the Cari-
doidae form an exception in this respect, — their
female genital openings being situated in the same
places as those of the males, that is on the external
side of the coxae of the posterior feet j see Krijyer,
loc. cit. p. 27, fig. 54, A. f. and fig. 97, B. g. (Hip-
polyte).

17 With Pagurus , the anal feet are developed
only on one side of the tail.

18 Many erroneous opinions have been enter-
tained by Zootomists on the subject of the female
genital organs of the Chilognatha. Thus, Trevi-
ranus (Verm. Schrift. II. p. 45) with Julus, and
Brandt (Muller's Arch. 1837, p. 325, Taf. XII.
fig. 8) with Glomeris , think they have observe^
double ovaries, as is also true of Stein (Muller's
Arch. 1842, p. 246, 248) ; but Ne wport (Phil. Trans.
1842, p. 99, or in Froriep's neue Not. XXI. p. 161 ;
see, also, Rymer Jones , Cyclop, loc. cit. p. 552,
fig. 315, 316) has noticed only a simple ovarian
tube with Julus , which I have been able to con-
firm and as for Glomeris , Brandt (liecueil, loc.
cit. p. 157) has himself recently perceived the same.

356

THE CRUSTACEA.

§ 293.

Chilopoda, also, the ovary is a single long tube, but extends from before
backwards and terminates by a short oviduct in the last segment of the
body. The Receptaculum seminis consists, here, of two ovoid capsules,
sessile or pedunculated, and inserted upon the sides of the extremity of the
oviduct. Into this last, moreover, just before its termination, long excre-
tory ducts enter from the two to four Glandidae sebaceae , which furnish
probably the viscous coating of the eggs.(19)

III. Male Crustacea.

§ 293.

The males of the Siphonostoma often differ very much from the females,
not only as to their external form, but also in their smaller size, — their
development being arrested at a very early period. On this account, some
are still unknown, and the organization of others is not understood.®

With the Caligina, however, they have received more attention, for in
size they are scarcely smaller than the females. Their posterior abdominal
segment, which, usually, is not as large as that of the other sex, has, at its
extremity, two genital openings, side by side. No testicles or excretory
canals have yet been observed, but it may be inferred that their external
form and their disposition are analogous to those of the oviducts.®

But with Dichelestium, the male organs are better known. The two
spheroidal testicles, and the somewhat tortuous Vasa deferentia of these

There has been the same misapprehension and
changing of opinion on the subject of the position
of the external genital openings. According to
Treviranus , and Brandt (loc. cit.), they should
be situated, with Julus and Glomeris , at the pos-
terior extremity of the body *, but Latreille (Hist.
Nat. d. Fourmis, 1802, p. 385) had before indicated
their true position with Polydesmus , and Savi
(Isis, 1823, p. 217) has Confirmed this with Julus.
Brandt (Recueil, loc. cit. p. 154) has since recti-
fied his error in respect to Glomeris. But Stein
has treated with most detail the subject of the geni-
tal openings with Julus and Glomeris, as well as
their seminal receptacles ( Muller's Arch. 1842, p.
246, Taf. XII. fig. 12, and Taf. XIII. fig. 15. See,
also, my observations, Ibid. 1843, p. 9).

19 For the female genital organs of Lithobius
and Scutigera , see L. Dufour (loc. cit. p. 89, PI.
V. fig. 1, 4) who regards the two stalkless Recep-
tacula seminis of Lithobius as a reservoir of the
four Glandulae sebaceae , and with Scutigera , as
the Glandes stbactes themselves. I cannot now
say whether these last organs are wanting in Scu-
tigera, or whether they escaped the attention of
this naturalist. Treviranus (Verm. Schrift. II.
p. 28, Taf. V. fig, 8) has very well observed the
simple ovary with its appendages of Lithobius ;
but he did not recognize the use of these last.
Kutorga (loc. cit. p. 8, Tab. I. fig. 5) has not been
more fortunate with the female genital organs of

* [ § 293, note 2.] Dana ( Caligus , loc. cit.
Amer. Jour. Sc. XXXII. p. 261, also, Report.
Crust. &c. p. 1344) has observed, with Caligus , a
well-formed male apparatus. Here, the testicle
(and the ovary, also, is the same) consists of a large
pyriform body of an internal glandular appearance,
and continuous into a duct extending the whole

Scolopendra. Those of Scolopendra morsitans
represented by Muller (Isis, 1829, p. 550, Taf. II.
fig. 5) are probably the male organs. Stein (loc.
cit. p. 239, Taf. XII. fig. 2, 8) has described very
accurately these organs with Lithobius, and Geo-
philus. This last has two long-pedunculated semi-
nal receptacles, and only two very long Glandulae
sebaceae.

1 Nordmann (loc. cit. p. 76, &c., Taf. V. VIII.
IX. X.) was the first to discover some of these
small male Crustacea which are nearly always
attached to their females in the neighborhood of
the genital openings. He observed them with
Achtheres, Brachiella , Chondr acanthus, and
Anchorella. But with an individual of the first
of these genera only, he found in the posterior part
of the body, four round masses, which perhaps
may be the internal genital organs. Burmeister
(Nov. Act. Nat. Cur. XVII. p. 320) refuses to
recognize these small males for the above-men-
tioned Siphonostoma, while Krbyer (Natur.
Tidskr. I. PI. III. or Isis, 1840, p. 710, Taf. I.
Tab. III.) sustains the opinion of Nordmann with
cogent arguments, and has described and figured
several of these males belonging to Lernaeopoda
and Lernaea. See also the description of Chon-
dr acanthus published by Rathlci, Nov. Act. Nat.
Cur. XX. p. 126, Tab. V. fig. 13.

2 See Krijyer, Naturh. Tidskr. I. PI. VI. or
Isis, 1841, p. 194, Taf. I. Tab. VI.*

length of the thorax into the abdomen where it
passes into the seminal organs. Described more
particularly, the testicles are rather larger than the
buccal mass, and are situated just anterior to the
stomach, in part beneath the base of the prehensile
legs, and the spine of the preceding pair. — Ed.

§ 293.

THE CRUSTACEA.

357

Crustacea completely resemble, as to form and situation, the ovaries and
oviducts of the females, except that the deferent canals are dilated, before
their termination, into two seminal vesicles.®

With Argulus, the males have, at the base of their last pair of feet, a
hook which is used in copulation. But as to their internal organs, there
are, as yet, no credible observations.®

With the Cyclopidae, the male organs consist of a single pyriform testi-
cle, the Vas deferens of which curves, first forwards, then backwards, and
opens at the base of the tail on the median line. In the lower end of this
canal, a homogeneous, cylindrical envelope is formed around the sperm, —
a real spermatophore, which has a narrow neck, and which the males glue
to the vulva of the females.® For effecting this last, the males have one
or even both of their antennae incrassated at their base, and provided with
a special article near their extremity, which gives these organs a forficulate
character.® When the male, by the aid of these antennae, has embraced
the abdomen of the female, he bends the posterior part of his body for-
wards, and seizes hold of the female a second time with the forficulate foot
of the second pair, at the same time grasping, with the other and digiti-
form foot, the spermatophore as it is escaping from the genital opening, and
attaches it to the vulva.®

As yet we possess only quite incomplete observations upon the males
of Daphnioidae, Cypridoidae, and Apodidae, which are found only at cer-
tain seasons of the year.® With the species yet observed, the testicles

3 Rathki, Nov. Act. Nat. Cur. XIX. p. 149, Tab.
XVII. fig. 17. I do not know how it is with the
males of the other Ergasilina, for as yet we know
only the females of these animals.

4 Jurine, who was the first to notice these
copulatory organs of the male Argulus, says he
perceived at the base of the penultimate pair of feet
a vesicular swelling containing, he thinks, a fecun-
dating liquid (Ann. du Mus. loc. cit. p. 448, PI.
XXVIII. fig. 1, 21).*

5 For the formation of these spermatophores with
Cyclopsina castor , and minutus, see my Beitr,
zur Naturg. d. wirbellosen Thiere, p. 36, Taf. II.
fig. 41-44, or Ann. d. Sc. Nat. XIV. 1840, p. 26,
PI. V. B. I have shown how their contents are
thrust out in passing the neck by the action of a
peculiar substance which swells when in contact
with water.

6 The two antennae are thus endowed, with Cy-
clops quadricornis , Cyclopsina minutus, and
alpestris ; while this organization obtains with one
antenna, only, with Cyclopsina castor, and Ano -
malocera Patersonii ; see the figures of Muller,
Entomostraca ; and Jurine, Hist. d. Monocles 5
also Vogt, Schweiz. Denkscli. loc. cit. p. 18, Taf.
II. 5 and Templeton, Trans, of the Entomol. Soc.
II. p. 35, PI. V. fig. 1, 5. The asymmetrical pos-
terior pair of feet has been figured by Jurine , loc.
cit. p. 61, PI. IV. fig. 2, PI. VI. fig. 11 ( Cyclop -

* [ § 293, note 4.] For the male genital organs
of Argulus , see Leydig (loc. cit. Siebold and
Kolliker's Zeitsch. II. p. 341). The testicles con-
sist of two pouch-like organs, situated, one in each
caudal fin 5 they send off, each, a vas deferens
which terminates in a seminal vesicle ; from this
last pass off two deferent ducts which end in the
common genital orifice. Just before reaching this
orifice, each of these ducts is joined by another

sina castor ), and by Templeton, loc. cit. p. 37,
PI. V. fig. 1, 18 (Anom aloe era).

1 These spermatophores, the true signification of
which was unknown until lately, are found, often
in the numbers of four to six, upon the same
female, after several coitions occurring at different
intervals 5 see Muller, loc. cit. Tab. XVI. fig. 5,
6, and Jurine, loc. cit. PI. IV. fig. 6 ( Cyclopsina
castor ) ; also Ramdohr, loc. cit. Taf. III. fig. 6, 9,
and Jurine, loc. cit. PI. VII. fig. 2, 14 ( Cyclop-
sina minutus). The spermatophores of this last
have the form of a curved horn, and become, after
a time, of a brown color. With Cyclops quadri-
cornis, the sperm does not appear to contain
spermatophores at the moment of its evacuation.

8 The males of Polyphemus, Limnadia, and
Apus, have not yet been observed. It is said, it is
true, that Kollar (Isis; 1834, p. 680) has discov-
ered those of Apus cancriformis ; but as yet
nothing definite has been learned about the matter.
At all events, the description given by Zaddach
(loc. cit. p. 53, Taf. I. fig. 15, 16, and Taf. III. fig.
1, P.) of the male genital organs of these Crustacea,
is unsatisfactory, for at the point, where, according
to this naturalist, are found the two male genital
orifices surrounded by short spineb, that is, on the
dorsal surface of the last segment of the body, are
found, with all the females also, similar orifices. It
is therefore probable that the ramose testicles which

coming from an accessory gland, which is pouch-
like, and stretches back of the seminal vesicle. As
auxiliary copulatory organs may be regarded a
hook situated on the anterior border of each of the
last pair of feet, dnd a nodule or papilla in the
posterior border of the penultimate pair, corre-
sponding, oppositely, with the hook. These hooks
were taken by Jurine for penises, and the papil-
lae for seminal capsules. — Ed.

358

TIIE CRUSTACEA.

§ 293,

consist of two spheroidal bodies which open externally, by two deferent
canals, in front of the tail.® The copulatory organs are attached to the
anterior feet, and consist of hooks and long bristles, by which these animals
adhere to the under surface of the thorax of the females. (10) With the
Branchiopoda, the male genital organs have a very remarkable organiza-
tion. The testicles consist of two long, straight, caecal tubes, stretching the
whole length of the tail. From the upper and dilated extremity of each
passes off, inwards and backwards, an excretory canal. These canals,
shortly after their origin, dilate into a seminal vesicle, and then pursue
their course between two longitudinal ridges which run backwards from the
base of the tail. At the posterior extremity of these ridges, they open near
a process covered with short spines. For the seizure and retention of the
females for copulation, the two anterior cheliform feet are provided with
antler-like hooks, and, also, at their base, with two peculiar, sometimes digiti-
form processes, curved above the front. (11)

With the Poecilopoda, the testicles consist of ramified canals situated in
the cephalothorax, which terminate at that same point on the first pair of
post-abdominal feet where are situated the genital openings with the
females, in two short, perforated, penis-like organs. (12)

With the Laemodipoda, Isopoda, and Amphipoda, the testicles consist
of two caeca situated by the side of the digestive canal, and continuous,
posteriorly, into two more or less flexuous deferent canals upon the sides of

Zaddach thinks he has observed with a small num-
ber of individuals which had been preserved in alco-
hol a long time, are only ovaries, the characteristics
of which have been effaced by the spirit. As to
Cypris , all we know about their males is that their
spermatic particles, according to Wagner (loc. cit.),
are disproportionately large, and that Ledermiiller
(Microscop. Gemuths-und Augen-Ergotzung, p.
141, Taf. LXXIII. fig. d.) thinks he has seen them
in copulation. Baird , also (Magaz. of Zool. and
Bot. I. p. 522), has often seen two individuals of
Cypris together, but was not sure that they were
copulating.*

9 Lov6&, in Wiegmann's Arch. p. 160, Taf. V.
fig. 13 ( Evadne ).

10 With the males of Daphnia, there is a hook
together with a small long lash on the two anterior
pairs of feet situated close under the head. The
first pair of feet situated on the beak in front of the
mouth, is very long and provided with two small
pointed hooks ; while, with the females, these feet

* [ § 293, note 8.] For the genital organs of
Cypris , see Zenker (Muller's Arch. 1850, p. 191).
They closely resemble those of Cyclops. He has
also described the spermatophores (Taf. V. fig. 6) *,
they are probably the very large spermatic parti-
cles seen by Wagner as mentioned above. These
observations I have recently confirmed. Wagner
and Leuckart (Cyclop. Anat. and Physiol. Art.
Semen , p. 496, note) must, therefore, be mistaken,
when they assert the hermaphroditic nature of
Cypris , and say, uWe beg to direct the attention
to the simultaneous appearande of egg together
with the spermatozoa in the same individual 5 and
therefore to the hermaphroditic condition of the
genitals in Cypris .” It is probable that they ob-
served only females, and if what they called such

have the form of two short, obtuse antennae
(Muller, Entomostr. p. 87, Tab. XII. fig. 6 *,
Ramdohr , loc. cit. p. 25, Taf. VII. ; Straus , M£m.
du Mus. V. p. 419, PI. XXIX. fig. 18, 19; and
Jurine , Hist. d. Monocles, p. 105, PI. XI. fig. 5-
8). With the males of Evadne , only the feet of the
first abdominal pair are provided each with a hook
and some pretty long bristles on their last two arti-
cles (Loven, loc. cit. p. 157, Taf. V. fig. 11). With
Isaura , on the other hand, the first two pairs of
abdominal feet are armed at their extremity with
stout nails (Straus, Mus. Senckenb. II. p. 123,
Taf. VII. fig. 4, 13 ; and Joly, loc. cit. p. 298, PI.
VII. fig. 2, 6).

11 Schaeffer, Der fischform. Kiefenf. fig. 3-11; and
Muller , Zool. danic. Tab. XLVIII. ( Branchipus ).
The frontal digitiform processes are especially de-
veloped with Chirocephalus ; see Prevost, in
Jurine's Hist. d. Monocl. p. 202, PI. XXII.t

12 Van der Hoeven, loc. cit. p. 20, PI. H. fig.
14, 18 (Limulus).

were really spermatic particles, the time of obser-
vation must have been soon after copulation. —
Ed.

f [ § 293, note 11. J For the details of the male
genital organs of Artemia and Branchipus , see
Ley dig (loc. cit. Siebold and Kolliker's Zeitsch.
III. p. 297). With these Phyllopods, these organs
consist of testes, vasa deferentia, and penises ; all
of which are double and symmetrical. The testes
consist, each, of an oblong pouch which is directly
continuous into its vas deferens ; and this last
passes into its penis. The two penises are situated
at the base of the abdomen, and point, bung-shaped,
backwards. Besides these parts, there is an exter-
nal organ, style-like, used in copulation (loc. cit.
Taf. VIII. fig. 4, a.). — Ed.

§ 293.

THE CRUSTACEA.

359

which, with the Idotheoidae, and Asellina, are two pairs of similar seminal
tubes. The two Vasa deferentia converge towards the posterior portion of
the body, where they pass into a double, or a single excretory canal, which
usually commences directly in front of the first pair of post-abdominal feet,
on the median line of the body.(13) With the Isopoda, this excretory canal
opens into a short, backwardly-curved penis, upon which are two long
processes (secondary penises) inserted on the internal border of the second
pair of feet.<14)

With the Stomapoda, the testicles consist of more or less ramified, gland-
ular lobes, from which pass off, laterally, two Vasa deferentia which ter-
minate in two hollow penises projecting at the base of the last pair of
feet. (1S)

With the Brachyura, and the short-tailed Anomura, the two testicles
consist of a net-work of very small semeniferous canals, occupying the lat-
eral portions of the cephalothorax, which gradually increase in size until
they pass into the long Vasa deferentia. These last form numerous convo-
lutions, and are finally continuous into two larger Ductus ejaculatorii.aG)
With the male Paguridae, the testicles are contained, like the ovaries, in
the tail. They consist of two large tubes which rapidly contract into a Vas
deferens, which is straight, at first, but afterwards spiral. This then
becomes larger and is gradually continuous into a Ductus ejaculatorius.a7)

With some Macrura, the cephalothorax contains two anterior and two
posterior testicular tubes, a portion of the last being extended even into
the tail ; while the first are connected, by a transverse anastomosis, behind
the middle of the body. The two posterior join with the two anterior in
the posterior extremity of the cephalothorax, and form on each side, a short,
narrow, deferent canal, which terminates in a larger Ductus ejaculatorius.aS)

13 With Cyamus , whose caudal extremity is
atrophied, the orifices of the two excretory ducts
are situated directly in front of the arms on two,
side by side papilliform penises ( Roussel de
Vauztme, loc. cit. p. 252, PI. VIII. fig. 7, 15).
With Aega , the two testicular tubes are curved S-
like on the sides of the oesophagus. Their defer-
ent canals are dilated at the posterior extremity
each into a seminal vesicle of the same S-like form.
They open through two approximated papillae
situated on the under surface of the last foot-bear-
ing abdominal segment (Rathkt, Nov. Act. Nat.
Cur. XX. p. 32, Tab. VI. tig. 16).

The three testicles which are found on each side
of the thorax with Idothea , Lygia , Lygidium ,
Asellus , Porcellio , Oniscus , &c., are very atten-
uated in front, but behind, are enlarged into a kind
of bulb before passing into the Vas deferens.
Cavoiini (loc. cit. p. 155) has already carefully de-
scribed these with Lygia oceanica. See, more-
over, Milne Edwards , Hist. d. Crust. PI. XII. fig.
13 (Lygia); Brandt, Mediz. Zool. II. p. 76, Taf.
XV. tig. 31 (Oniscus), and Lereboullet , loc. cit.
p. 132, PI. V. fig. 134 (Lygidium).

H The copulatory organs of the Asellina have
been described and figured by Brandt (loc. cit. p.
73 and Taf. XV. fig. N. V. Z.). Treviranus, also
(Verm. Schrift. I. p. 59, 74, Taf. VIII. fig. 48, 49,
Taf. XII. fig. 65-67), has well represented them
with Porcellio, and Asellus, although he entirely
overlooked the six testicles of these Crustacea.
The penis, and its auxiliary stalks, which, with the
Isopoda are always concealed in the midst of the
branchial lamellae, have been figured by Degeer
(Abhandl. zur Geschichte d. Insekt. VII. p. 191, Taf.
XXXII. fig. 6, 20), and by Rathkc (loc. cit. p. 125,

Taf. IV. fig. 16, 17, f. h. 25) with Idothea ento-
mon ; but this last author is quite mistaken about
the internal genital organs, having confounded
the male with the female (loc. cit. p. 123, fig. 22).
I have already corrected this error in Muller's
Arch. 1837, p. 434. Savigny, also (Descript, de
l’Egypte, Crust. PI. XII. XIII.), has given beauti-
ful figures of the copulatory organs of Sphaeroma,
Lygia, Idothea, Tylos, and Oniscus. The
secondary or auxiliary penises have been repre-
sented by Lereboullet, loc. cit. p. 120, PI. V. fig.
19 (Lygidium), and by Milne Edwards , Arch, du
Mus. II. p. 21, PI. II. fig. 3.* b.1. ( Serolis ), and
Ann. d. Sc. Nat. XV. 1841, PI. VI. fig. 4 (Lygia).

15 As to both form and position, the multilobular
testicles of Squilla almost exactly resemble the
ovaries. But their lateral lobes are not blended
together at the anterior extremity of the body, and
the two deferent canals are given off laterally
(Delle Chiaje , Descriz. &c. Tav. LXXXVI. fig.
4). The two penises of these Crustacea have been
correctly figured in Desmaret's Considerat. &c.
PI. XLII. n. n.

For the male organs of My sis, of which the tes-
ticles are composed of only a few lobes, see Frey ,
loc. cit. p. 26.

16 Cavoiini , loc. cit. p. 144, and Milne Ed-
ivards, Hist. d. Crust. I. p. 166, and Cyclop, loc.
cit. p. 783, fig. 418 (Cancer pagurus).

V Swammerdamm , loc. cit. p. 86, Taf. XI. fig. 6,
and IJelle Chiaje , Descriz. &c. Tav. LXXXVI.
fig. 6.

]8 Milne Edwards, Hist. d. Crust. PI. XII. fig.
15 (Homarus), and Delle Chiaje, loc. cit. Tav.
LXXXVII. fig. 6 (Scyllarus).

360

THE CRUSTACEA.

§ 293.

With other Macrura, the testicles consist only of a trilobed glandular mass
covering the pyloric portion of the stomach, and from which pass off two long,
very flexuous Vasa deferentia, which are dilated, near their extremity, into
a nearly straight Ductus ejacidalorius.a',} The excretory ducts of the sperm
are very distinct with the Decapoda, when filled with this fluid, from their
chalk-white color. With many species, the sperm, as it approaches the end
of these ducts, is divided into portions, around which capsules or spermato-
phores are developed.

These last are usually pyriform, and connected together by a common
band.<20) The external genital organs of the male Decapoda are quite
varied, although these excretory ducts almost invariably open on the coxal
joint of the last pair of feet.<21) With the Paguridae, and Macrura, the
male genital orifices are surrounded by a soft sphincter, without any trace
of a penis, but out of which the Ductus ejacidatorius is perhaps pro-
truded during copulation. (22) But with the Brachyura and short-tailed
Anomura, on the contrary, there are two longer or shorter tubular pe-
nises, always covered by the tail, which is pressed against the belly. <23)
With very many Decapoda, the two feet of the first caudal segment are
transformed into pedicellated processes (secondary penises), the extrem-
ity of which is sometimes grooved. With some short-tailed Anomura, the
feet of the second post-abdominal pair take pai’t also in the act of copula-
tion, and, for this purpose, are prolonged into stalk-like organs. (24)

Among the Myriapoda, the (tlomerina have two testicular tubes extend-
ing into the abdomen and composed of numerous vesicles partially blended
together. They unite in the thorax into a common Vas deferens. With
the Julidae, the testicles have a similar structure, but the vesicles open
separately into the external side of the two Vasa deferentia, which are close
together, dfid are connected, in a ladder-like manner, by numerous trans-

19 With Astacus ; see Roesel , loc. cit. Taf.
LVIII. fig. 9, and Taf. LX. fig. 23 ; Suckow, loc.
cit. Taf. X. fig. 15 j Brandt , Media. Zool. II. Taf.

XI. fig. 14 •, Milne Edwards , Hist. d. Crust. PI.

XII. fig. 14 ; and Cams, Erlauterungstaf. Heft. V.
Taf. III. fig. 9.

20 These spermatophores, first made known by
Kblliker , are bound together, with Galathea , by
ramified pedioles ; and with Pagurus , by simple
filaments •, see Kblliker , Beitr. zur Kenntniss d.
Geschlechtsv. &c. p. 9, fig. 21, 22, also, Schweiz.
Denksch. VIII. p. 52, fig. 32-35. See, also, the
description which I have given of the spermato-
phores of Pagurus Bernhardus , in Muller's Arch.
1842, p. 136, note 1. But one must be careful not
to take, in the testicles of the Decapoda, the mother-
cells in which are developed the radiating cells for
the spermatophores.

21 The land crabs make an exception in this re-
spect, their male genital orifices being situated on
the last segment of the body ; see Milne Edwards ,
Ilist. Nat. d. Crust. I. p. 168, PI. XVIII. fig. 6
( Gecarcinus ).

22 For Astacus , see the figures cited above *, for
Palinurus , Milne Edwards , Hist. d. Crust. PI.
XXIII. fig. 2 ; and for Hippolyte , Krbyer , loc.
cit. p. 27, fig. 54, B. f.

23 There are two very short, and soft penises
with Maia , Pisa , Cancer , Grapsus , Lupea ,
Gecarcinus , Porcellana , Homola , &c. They are
long, hard, and point forwards with Dromia.

24 The canaliculated, secondary penises may be
very easily seen on the first caudal segment of
Homarus, Nephrops and Astacus; see Roesel , loc.
cit. Taf. LVI. •, and Cams , Erlauterungstaf. Heft.

V. Taf. III. fig. 12 {Astacus). In this last ge-
nus, these organs are slightly spiral at their extrem-
ity. These penises are long, secondary, and con-
cealed under the tail with the male Brachyura and
Anomura, with which the majority of the other
anal feet are wanting ; see Milne Edwards , Hist,
d. Crust. I. p. 169, PI. III. fig. 6, 15, 16 (Maia) ;
in this genus the two pairs of anal feet are rudi-
mentary. This abortion is observed, also, with
Grapsus , Cancer , Lupea , Ocypoda, Porcellana ,
&c. See the beautiful figures of Savigny , in
Descript, de l’Egypte, Crust. PI. II. -VII., and
Cavolini , loc. cit. Taf. II. fig. 10 (Grapsus). With
Dromia , the two feet of the second caudal segment
have the form of two long spines. With Homola ,
the same feet are equally pedicellated, but termi-
nate with a kind of sucker, and, therefore, are un-
doubtedly auxiliary in the act of copulation. No
auxiliary organs have been found with Galathea ,
Palinurus , and Sc y liar us ; but in the last two
of these genera tfie feet of the first caudal segment
are wholly wanting. With the Caridoidae, the
copulatory organs are usually absent, and the first
pair of anal feet does not differ from the others ;
with Crangon, only, have I found the internal pro-
longation of these feet highly developed and gla-
brous ; while with the posterior feet, it is very
small, and, like the external one, very hairy. Ac-
cording to Joly (loc. cit. p. 43, PI. III. fig. 20), it
is somewhat similar with Caridina. Krbyer (loc.
cit, p. 27, PI. II. fig. 54, B. g.) has observed, with
Hippolyte , between the feet of the fourth pair, two
short hooked appendages which may be regarded
as secondary penises.

<§» 294.

THE CRUSTACEA.

361

verse anastomoses. In front, the testicular vesicles are lost in these canals,
which finally diverge from each other in an arcuate manner, as is also true
of the Vas deferens of the Glomerina. In this manner, these canals, as
two Ductus ejaculatorii, extend to a triangular scale situated under the
third thoracic segment, and terminate at the lower angles of this scale in
two short, conical, penis-like protuberances. <25)

With the Chilopoda, the male organs are very complicated and formed
upon a wholly different type. Their orifices are always situated at the
posterior extremity of the abdomen. With some species, there is only a
single, long, testicular tube into which pass two lateral, also very long, coe-
cal tubes (Epididymes ?). At their point of junction, arise two short Vasa
deferentia , which terminate in a common, short, campanulate penis. Other
Chilopoda have two to three varicose testicular tubes which anastomose,
loop-like, at both of their extremities, and terminate, at last, in a longer or
shorter Vas deferens , which bifurcates in its course, but its branches come
together again in a short penis. With all the Chilopoda, the common geni-
tal orifice is connected with the short excretory ducts of two to four oblong
accessory glands, the nature of which is yet unknown. (26)

§ 294.

The Development of the Crustacea occurs, as with all Arthropoda, ac-
cording to a special type.(1)

After the disappearance of the germinative vesicle, a partial segmentation
occurs upon a given point of the surface of the vitellus. By this process, a
transparent, finely-granular, proligerous disc is formed.® The borders of
this disc gradually extend over, and finally cover the surface of the vitel-
lus. It is then changed into a proligerous vesicle enclosing the remainder
of the vitellus.

At the pole of the egg where the proligerous disc is first formed, are de-

25 For the male organs of the Chilognatha, see
Newport , Philos. Trans. 1842, loc. cit. p. 99 •,
Rymer Jones , Cyclop. III. p. 551, fig. 314 ; and
Stein , in Muller's Arch. 1842, p. 246, Taf. XII.-
XIV. (Julus, Polydesmus , and Glomeris). The
two testicles of Glomeris were formerly described
as ovaries by Brandt ; see his Beitr. loc. cit. p.
325, Taf. XII. fig. 8 ; but he has rectified this in his
Recueil, loc. cit. p. 157. For the copulatory
organs of the Julidae, may be cited, also, the re-
searches of Latreille , and Savi (loc. cit.).

26 Lithobius has only a single testicular tube
with two epididymes and four accessory glands
( Treviranus, Verm. Schrift. II. p. 25, Taf. V. fig.
7 •, L. Dufour , loc. cit. p. 87, PI. V. fig. 2, 3, and
Stein , loc. cit. p. 240, Taf. XII. fig. 1). Geophi-
lus has three interanastomosing, varicose testicles,
and two accessory glands (Stein, loc. cit. p. 243,
Taf. XII. fig. 7). Judging from Muller's figure
(loc. cit. Taf. II. fig. 5), Scolopendra morsitans
hag also two anastomosing varicose testicles. But
this point is made somewhat uncertain from the
researches of Kutorga (loc. cit. p. 10, Tab. II. fig.
4-6), who has shown positively the existence of four
accessory glands with this animal. L . Dufour's
figures (loc. cit. p. 97, PI. V. fig. 5) of the male
organs of Scutigera indicate here a very different
organization. There are two testicular tubes which
unite loop-like at the anterior extremity and then
send off a long very flexuous canal which has two

31

pedunculated vesicles (Vesiculae seminales). The
posterior extremity of these testicles is continuous
into two Vasa deferentia which become dilated
into as many Ductus ejaculatorii. Perhaps this
abnormal organization of these animals in this re-
spect, will be reduced from further researches to
the type of the Scolopendra.

1 The embryology of Crustacea has been brought
out, especially by the numerous and exact re-
searches of Rathki ; see his Untersuch. uber d.
Bild. u. Entwickel. d. Flusskrebses, 1829, then his
notes in Burdach's Physiol. II. 1837, p. 250 ; his
Abhandl. zur Bild. u. Entwickel. d. Mensch. u. d.
Thieve, 1833 •, his Mittheilung. fiber d. Entwickel.
d. Decapoden, in Muller's Arch. 1836, p. 187, or
in Wiegmann's Arch. 1840, 1. p. 241 •, and in the
Neuest. Schrift. d. Danzig, naturf. Gesellsch. III.
lleft. IV. 1842, p. 23 *, then, Zur Morphol., Reise-
bemerk. aus Taurien, 1837 5 his Beobacht. u.
Betracht. fiber d. Entwickel. d. Mysis vulgaris, in
Froriep's neue Not. XXIV. 1842, p. 181 ; and
finally his Comment, de Animal. Crust, generat.
1844. See, also, Erdl , Entwickel. d. Iluramereies,
1843 •, and Joly, Sur le developp. des Caridina, in
the Ann. d. Sc. Nat. XIX. loc. cit. p. 57, PI. IV.

2 Cancer maenas forms perhaps the only ex-
ception in this respect. Here, the segmentation ap-
pears to be complete ; see Rathki , in Froriep's
neue N ot. loc. cit. p. 182 *, and Erdl , loc. cit. p.
27.

362

THE CRUSTACEA.

§ 294

veloped the ventral portion together with the abdominal cord of the future
embryo ; while, at the opposite pole, where the borders of the disc meet, the
dorsal portion of the animal appears. Quite early, the blastoderma can be
seen composed of an external or serous, and of an internal or mucous
layer. This last, after having enveloped the entire vitellus, is changed
gradually into the alimentary canal. The hepatic organs are only dever-
ticuli of this last, while the antennae, the oral apparatus, the feet, and the
branchiae, are developed from the serous layer.

The embryos, thus formed, differ considerably, and their form is often sq
dissimilar from that of the adult animal, that, during their ulterior develop-
ment, there is a real metamorphosis, which takes place by more or less
numerous stages coincident with the act of moulting.

An embryonic type quite general among the lower Crustacea, that is,
the Oirripedia, Siphonostoma, Lophyropoda and Phyllopoda, is that which
was first observed with Cyclops. There is here a long series of metamor-
phoses. The monocle-like larvae have an ovoid, unarticulated body, usually
provided with a single, simple eye, and two or three pairs of oar-like ap-
pendages covered with long hairs. <3)

With some Brachyura, there is an equally well-marked metamorphosis ;
for, in leaving the egg, they have a long tail and two very large eyes ; but
with the first moulting they acquire two enormous, spur-like apophyses, one
on the front, and the other on the back.(4)

3 It is remarkable that the young Cirripedia,
which are hexapod, have the characteristics of
the larvae of Monocles ; see Thompson , Zool.
Research, loc. cit. p. 69, PI. IX. ( Balanus ) ; Bur-
rneister, Beitr. loc. cit. p. 12, Taf. I. (. Lepas ) ;
Goodsir , Edinb. New Philos. Jour. No. 69, July,
1843, p. 97, PI. HI. IV., or Isis, 1844, p. 901,
Taf. I. fig. 8, 11-17 (Balanus). The larvae of
these Crustacea, before becoming fixed in order
to undergo their metamorphoses, change into a
bivalve animal resembling Cypris. Among the
Siphonostoma, the monocle-like embryos are very
general. Nordmann (loc. cit. p. 11, &c., Taf. II.-
VII.) has recognized larvae of this kind, some with
three (Ergasilus and Lernaeocera), and others with
only two (Achtfibres and Trac/ieliastes) pairs of
feet. According to Kollar (loc. cit. p. 87, Taf. X.
fig. 10), the embryos of Basanistes are monocle-
like and have six feet, as are also those of
Lernaeopoda described by Rathke (Zur Mor-
phol. &c. p. 34, Taf. I.). Goodsir (loc. cit. No.
65, July, 1842, p. 178, PI. III. fig. 19-23) has
observed embryos with four feet in the eggs of
Caligus. The larvae of Nicothoe (Rathkt, Nov.
Act. Nat. Cur. XX. p. 109, Tab. V. fig. 8-10) and
of Argulus (Muller , Entomostr. p. 122, Tab. XX.
fig. 2, and J urine , loc. cit. p. 453, PI. XXVI. fig.
4) form an exception in this respect, for when
they leave the egg they have two simple eyes, an

* [ § 294, note 3.] For many highly-interesting
details on the economy of the Entomostraca, see
Baird (British Entomostr. &c. loc. cit. passim).
These details with their corresponding figures will
render clear many obscure economical points al-
luded to above. For the embryology of Argulus ,
Artemia and Branchipus , see Leydig , loc. cit.
Siebold and Kolliker's Zeitschrift, II. p. 344, and
III. p. 304. The descriptions of this observer are
quite rich in details upon the successive appear-

articulated body, and more than three pairs of feet.
Those of the Cyclopidae which have six feet have
been known a long time. But Muller (Entomostr.
p. 39, Taf. I. II.) formerly divided them under the
names of Nauplius and Amymone. See Degeer
Abhandl. &c. VII. p. 181, Taf. XXX. (Cyclops)-,
Ramdohr , loc. cit. p. 5, &c., Taf. I. III. *, but
especially Jurine , Hist. d. Monocl. p. 15, & c., PI.
I. -VII. (Cyclops and Cyclopsina). The young
Daphnioidae and Cyprido'idae, on the contrary, re-
semble the adults on their escape from the egg. The
simple eye is evidently the result of a very early
fusion of two eyes ; see Jurine , loc. cit. p. 113,
PI. VIII. IX. (Daphnia and Cypris ); Rathki ,
Abhandl. z. Biklungs u. Entwickelungsgesch. &c.
]>. 85 (Daphnia and Lynceus) ; Baird , Magaz.
of Zool. and Bot. I. p. 522, and II. PI. V. fig.
12 (Cypris) ; finally Lovin, loc. cit. p. 161, Taf.
V. fig. 12 (Evadne). Of the Phyllopoda, the mo-
nocle embryos of the Apodidae have two pairs
of feet, while those of the Branchiopodahave three ;
see Schaejfer, Der krebsartige Kiefenf. p. 118, Taf.
I. fig. 3 •, and Zaddach , loc. cit. p. 55, Tab. IV.
fig. 1-3 (Apus) Joly , loc. cit. p. 321, PI. IX. fig.
39 (Isaura) Prevost, in Jurine'1 s Ilist. <1. Mon-
ocl. p. 214, PI. XX. fig. 9 (Chirocephalus)-, and
Joly , loc. cit. p. 257, PI. VII. fig. 4 (Artemia) J
4 These embryos with such singular forms, have,
hitherto, been figured as separate genera under the

ances of the different organs. Argulus is quite
well developed when hatched, its muscles are trans-
versely striated and the locomotive organs well
formed. Artemia has, at this period, two anten-
nae, two pairs of feet on the head, and the red pig-
ment Spots on the forehead, but these last have as
yet no light-refracting body. The muscles are still
without striae, and even here and there are filled
with vitelline globules. The heart and blood-cir-
culation are still unformed. — Ed.

§ 294,

THE CRUSTACEA.

363

The young of the Paguridae and Macrura differ more or less from the adult
animals.® But this difference is less with the Poecilopoda, Laemodipoda,
Stomapoda, Isopoda, and Amphipoda.® Finally, with the Myriapoda, the
metamorphosis is limited to the increase of the number of the segments of
the body, and of the feet.(7)

names Megalops , Monolepis and Zoea ( Milne
Edwards , Hist. d. Crust. II. p. 260, 431), until
Thompson perceived their true nature ; see his
Zool. Research. &c. PI. I. and his Memoir on the
double Metamorphosis in the Decapodous Crusta-
cea, in the Philos. Trans. 1835, pt. II. p. 539 ; see
also the Edinb. New Philos. Jour. No. 20, p. 221,
and the Entomol. Magaz. No. 14, p. 370. Although
these observations have been confirmed from dif-
ferent sides, yet they did not, at first, receive full
assent, especially on account of the authority of
Rathke (Muller's Arch. 1836, p. 187), who opposed
them. Templeton (Trans, of the Entomol. Soc.
II. p. 115, PI. XII.) and Westwood (Philos. Trans.
1835, pt. II. p. 311, PI. TV.) refuse to give up the
genus Zoea ; but since Du Cane (Ann. of Nat.
Hist. III. 1839, p. 438, PI. XI. or Froriep's neue
Notiz. XIII. p. 5, fig. 10-13), has verified, with
Cancer maenas , the observations of Thompson ,
and Rathke himself (Wiegmann's Arch. 1840, I.
p. 246, and Neuest. Danzig. Schrift. loc. cit. p. 39,
Taf. IV.) has seen the embryos of Hyas under the
form of a Zoea , this wonderful metamorphosis of
the Brachyura can no longer be doubted. See
also Steenstrup , in the Oversigt over det kgl.
danske Videnskabernes Selskabs Forhandlinger,
1840, p. 15, or Muller's Arch. 1841, p. 218 (Hyas),
and Goodsir , Edinb. New Philos. Jour. No. 65,
1842, p. 181, PI. III. fig. 16-18 (Cancer maenas).

5 The embryos of Pagurus which have a frontal
spine, were also, before the discovery of Thomp-
son. taken for species of Zoea ; see Philippi , in
Wiegmann's Arch. 1840, I. p. 184, Taf. III. fig.
7, 8 ; also Rathki, Ibid. p. 242, and, Danzig.
Schrift. loc. cit. p. 29, Taf. III. ; Steenstrup , loc.
cit. ; and Goodsir , loc. cit. No. 65, p. 182, PI. III.
fig. 12-14. The difference in form between the

embryos and the adults is less marked with Asta-
cus , Homarus and other Macrura ; see Rathke ,
Entwick. d. Flusskr.) and in the Danzig. Schrift. loc.
cit. p. 23, Taf. II. (Homarus) ; Du Cane , Ann. of
Nat. Hist. II. 1839, p. 178, PI. VI. VII. or Fro-
riep's neue Notiz. XIII. p. 3, fig. 4^9 (Palae-
mon and Crangon) ; Krdyer , Monogr. loc. cit. p.
37, PI. VI. (Hippolyte and Homarus) ; Joly , Ann.
d. Sc. Nat. XIX. loc. cit. PI. IV. ( Caridina ), and
Erdl , loc. cit. p. 18, Taf. III. IV. {Homarus).

6 According to Milne Edwards (Instit. 1838,
No. 258, p. 397), a cephalothorox and abdomen may
already be distinguished with the hatching embry-
os of Limulus. But the abdomen has only three
pairs of appendages and its long spine is wholly
wanting. This naturalist, also, has figured an
embryo of Cyamus which closely resembles the
adult (Ann. d. Sc. Nat. III. 1835, p. 328, PI. XIV.
fig. 14).

For the embryos of the Isopoda and Amphipoda,
see Rathke , Abhandl. loc. cit. ; Ann. d. Sc. Nat.

II. 1834, p. 139, PI. XI. ; Zur Morphol. &c. 41,
Taf. II. III. ( Bopyrus , Idothea , Janira , Lygia
and Amphithbe) ; Nov. Act. Nat. Cur. XX. p. 49,
Tab. I. (Phryxus) ; also Milne Edwards, Ann. d.
Sc. Nat. III. 1835, p. 323, PI. XIV. ( Cymothoa ,
Anilocra, Phronima and Amphithoe) ; finally
Rathke, in Wiegmann's Arch. 1839, loc. cit. Taf.
VI. (Mysis).

1 See Gervais, Ann. d. 1. Soc. Entomol. de
France, 1837, and Institut. 1839, p. 22; Waga, Rev.
Zool. 1839, No. 3. p. 76, or Wiegmann's Arch.
1840, II. p. 351 ; and especially Newport, Philos.
Transact. 1842, part II. p. 99, and Cyclop, loc. cit.

III. p. 353, fig. 317-326, also in Froriep's neue
Notiz. XXI. p. 161.

BOOK THIRTEENTH.

ARACHNOIDAE.

CLASSIFICATION.

§ 295.

The Arachnoidae, which are organized after very different types, have
always four pairs of feet. The Tardigrada form no exception in this
respect ; and although it may appear singular to find them placed in this
class, yet this seems their most proper place ; only they should be placed at
the head, for they form the transition of the Arachnoidae to the Annelides,
exactly as do the Cirripedia from the Crustacea to the Acephala.*

The Arachnoidae are usually defined as Arthropoda wanting the anten-
nae ; this, however, is incorrect, for these organs are not wanting, strictly
speaking, but take the place of the mandibles, which are absent, as will be
shown hereafter.

ORDER I.

Cephalothorax multi-articulate. Special respiratory organs wanting.

SUB-ORDER I. TARDIGRADA.

Legs rudimentary. Abdomen wanting.

Genera : Milnesium, Macroliotus, Emydium.

SUB-ORDER II. PYCNOGONIDAE.

Legs very much developed. Abdomen rudimentary.

Genera : Nymphon, Ammothea, Pallene, Phoxichilidium, Pariboea, Endeis,
Phoxichilus, Pycnogonum.

* [ § 295.] For a detail of the data which fully Stellung der Tardigraden, in Siebold and Kdlliker’s
justify this position of the Tardigrada, see Kauf- Zeitsch. III. 1851, p. 220. — Ed.
mann , Ueber die Entwickelung und systematische

$ 295.

THE ARACHNOIDAE.

365

ORDER II.

Cephalothorax unarticulated, or biarticulated. Respiratory organs con-
sisting of tracheae.

SUB-ORDER III. AC ARINA.

Abdomen unarticulated and fused with the cephalothorax. Palpi simple.
Family : Ac are a.

Genera : Demodex, Sarcoptes, Glycyphagus, Tyroglyphus, Melichares,
Dermaleichus, Acarus, Pteroptus.

Family : Hydrachnea.

Genera : Limnochares , Arrenurus, Eylais, Diplodontus, Hydrachna, Atax.
Family : Ohibatea.

Genera : Hoplopkora, Oribates, Zetes, Pelops, Damaeus.

Family : Gamasea.

Genera : Dervianyssus, Uropoda, Gamasus, Argas.

Family : Ixodea.

Genus : Ixodes.

Family : Bdellea.

Genera : Bdella, Molgus.

Family : Trombidina.

Genera: Erytkraeus, Trombidium, Smaridia, Tetranyckus, Rhynckolo-
phus, Rhaphygnathus, Penthaleus.

SUB-ORDER IV. OPILIONINA.

Abdomen articulated, but indistinctly separated from the cephalothorax.
Palpi simple.

Genera : Phalangium, Gonyleptes, Eusarcus.

SUB-ORDER V. PSEUDO SCORPII.

Abdomen articulated, but indistinctly separated from the cephalothorax.
Palpi forficulate.

Genera : Obisium, Ckelifer.

SUB-ORDER VI. SOLPUGIDAE.

Abdomen articulated, distinctly separated from the cephalothorax.
Palpi simple.

31*

Genus : Galeodes.

866

THE ARACHNOID AE.

$ 295.

ORDER III.

Abdomen and cephalothorax unarticulated, distinct from each other.
Respiratory organs consisting of tracheae and lungs.

SUB-ORDER VII. ARANEAE.

Genera : Mygale, Thomisus, Uptiotes, Lycosa, Dolomedes, Salticus, Seges-
tria , Dysdera, Scytodes, Clubiona, Drassus, Argyroneta, Clotho,
Agelena, Lachesis, Tegenaria, Micryphantes, Theridion, Linyphia,
Epeira, Tetragnathus.

ORDER IV.

Abdomen articulated. Cephalothorax unarticulated. Respiratory or-
gans consisting only of lungs.

SUB-ORDER VIII. PHRYNIDAE.

Abdomen distinct from the cephalothorax. Cheliceres unguiculate.
Genera : Thelyphonus, Phrynus.

SUB-ORDER IX. SCORPIONIDAE.

Abdomen indistinctly separated from the cephalothorax. Cheliceres
forficulate.

Genera: Scorpio , Buthus, Androctonus.

BIBLIOGRAPHY.

Leeuwenhoek. Continuatio arcanorum naturae, 1719, Epist. 138, p.
312.

Roesel. Insekten-Belustigungen, Thl. IV. 1761, p. 241.

Degeer. Abhandlungen zur Geschichte der Insekten, VII. 1783.
Hermann. Memoire apterologique, 1804.

.1. F. Meckel. Beitrage zur vergleichenden Anatomie, I. Hft. 2, 1809,

p. 105.

Treviranus. Ueber den inneren Bau der Arachniden, 1812. Ver-
mischte Schrift. anat. u. physiol. Inhalts. I. 1816. Ueber d. Bau d. Nigua
( Acarus americanus), in his Zeitsch. f. Physiol. IV. 1831, p. 185.

Serres. Memoires du Mus. d’hist. Nat. V. 1819, p. 86.

Leon Dufour. Ann. gener. d. Sc. physicp d. Bruxelles, IV.— VI.

J. Mhller. Beitrage zur Anatomie des Scorpions, in Meckel's Arch. f.
Anat. 1828, p. 29.

Lyonet. Anat. de differentes espec. d’Insectes, in the Mem. du Mus.
d’hist. Nat. XVIII. 1829, p. 282, 377.

Brandt. Medizin. Zool. II. 1833, p. 87. Recherch. sur l’anat. d. Araig-
nees, in the Ann. d. Sc. Nat. XIII. 1840, p. 180.

Savigny. Descript, de l’Egypte. Hist. Nat. Arachnides, PI. I.-IX.
Audouin. Lettre contenant des recherches sur quelques Araignees

$ 295.

THE ARACHNOID AE.

367

parasites, in the Ann. d. Sc. Nat. XXV. 1832, p. 401. Cyclop, of Anat.
I. 1836, p. 196, Art. Arachnida.

Duges. Recherches sur l’ordre des Acariens, in the Ann. d. Sc. Nat.
I. 1834, p. 5, and II. p. 18; also, Sur les Araneides, Ibid. VI. 1836, p.
159.

Walckenaer. Hist. Nat. d. Insectes apteres, I.-III. 1837-44.

Boyer e. Sur les Tardigrades, in the Ann. d. Sc. Nat. XIV. 1840, p.
269.

Van der Hoeven. Bijdragen tot de lcennis van het geslacht Phrynus,
in the Tijdschrift voor natuurlijke Geschiedenis en Physiologic, IX. 1842,

p. 68.

Grube. Einige Resultate aus Untersuchungen iiber d. Anat. d. Aranei-
den, in Midler's Arch. 1842, p. 296.

Menge. Ueber d. Lebensweise d. Arachniden, intheNeuest. Schrift. d.
naturf. Gesellsch. in JDanzig. IV. Hft. 1, 1843, p. 1.

Tulk. Upon the anatomy of Phalangium opilio, in the Ann. of Nat.
Hist, XII. 1843, p. 153, or in Froriep's neue Notiz. XXX. 1844, p. 97.

Dujardin. Sur les Acariens, in the Comp. rend. XIX. 1844, p. 1158,
and Mem. sur les Acariens, in the Ann. d. Sc. Nat. III. 1845, p. 5.

Quatrefages. Mem. sur l’organis. d. Pycnogonides, in the Ann. d. Sc.
Nat. IV. 1845, p. 69.

Blanchard. Observat. sur l’organis. d’un type de la classe des Arach-
nides, le genre Galeode, in the Comp. rend. XXI. 1845, p. 1383.

Wasmann. Beitrage zur Anat. d. Spinnen, in the Abhandl. d. natur-
wissensch. Vereins in Hamburg, 1846.

ADDITIONAL BIBLIOGRAPHY.

Wilson. Researches into the Structure and Development of a newly-
discovered parasitic animalcule of the Human Skin, — the Entozoon folli-
culorum, in the Philos. Trans. 1844, p. 305.

Wittich. Dissertatio sisters, observ. quaed. de Aranearum ex ovo
evolut. Halis, 1845.

Die Entstehung des Arachnideneies im Eierstocke ; die ersten

Vorgange im demselben nach seinem Verlassen des Mutterkorpers ; in
Mvller's Arch. Hft. 2, 1849, p. 113.

Leuckart. Ueber den Bau und die Bedeutung der sog. Lungen bci den
Arachniden, in Siebold and Kolliker's Zeitsch. 1849, I. p. 246.

J. V. Carus. Ueber die Entwickelung des Spinneneies; in Siebold and
Kolliker's Zeitsch. II. 1849, p. 97.

Blanchard. De l’Appareil circulatoire et des Organes de la respiration
dans les Arachnides, in the Ann. d. Sc. Nat. XII. 1849, p. 317.

Dufotir. Observations sur l’Anatomie du Scorpion, in the Ann. d. Sc.
Nat. XV. 1851, p. 249.

Kaufmann. Ueber die Entwickelung und systematische Stellung der
Tardigraden, in Siebold and Kolliker's Zeitsch. III. 1851, p. 220. — Ed.

368

THE ARACHNOIDAE.

§§ 296, 297.

CHAPTER I.

EXTERNAL ENVELOPE AND CUTANEOUS SKELETON.

§ 296.

The external envelope of the Arachnoidae is usually soft, or coriaceous,
rarely horny ;a> but in no instance does it possess a proper contractility.
In place of this, however, it is extensible in the highest degree with many
species. This extensibility is seen especially with those species which are
accustomed to long fasts, having only an occasional opportunity to fill their
digestive canal with food consisting of the animal juices.®

The envelope is composed here, as with all the Arthropoda, chiefly of
chi tine.® To this last are undoubtedly due its solidity and indestructibility,
which may be observed with the small and delicate Acarina and Tardi-
grada, not only when it is in a fresh state, but even after it has been cast
off by a kind of moulting.®

§ 297.

With most Arachnoidae, the cutaneous envelope may be separated into
two tunics ; an external and an internal. The first is the more solid and
thick, and, in the cephalothorax and the extremities, has often a cellular
structure. Upon the abdomen of the Araneae and Acarina, it presents
peculiar, waving markings which, as concentric rings, surround the base of
the hairs ;0) but it is difficult to determine if they are due to delicate
plicae, or the effect of the intimate structure of the skin. With Ixodes ,
only, these prominent lines appear, unmistakably, as folds of the epidermis,
for they completely disappear when these animals are gorged with food.

The epidermis is often provided with papillae, clavate excrescences,
spines, bristles, simple or plumose hairs, and even, sometimes, with scales.®
These various cutaneous formations, which are usually hollow, cither
occupy only certain points, or are extended over the whole surface of the
body, giving it a velvety or a furry aspect.

The internal tunic of the skin consists of a thin, always colorless mem-
brane, finely granular or fibrillated, which is perforated at those points
where there are hair-like or other formations of the epidermis.® Directly
beneath this membrane, which, undoubtedly, reproduces the epidermis after

1 For example, with the Scorpionidae and Phry-
nidae. The cutaneous envelope is hardest and
most fragile with the Oribatea, where it breaks like
glass from the lightest pressure.

2 For example, with Ixodes , and Argas, as also
with the parasitic larvae of certain Hydrachnea
and Trombidina, known undej: the names of Achly-
sia and Leptus.

3 Lassaigne , Compt. rend. XVI. 1843, No. 19,
or Froriep’s neue Not. XXVII. p. 8, and Schmidt ,
Zur vergleich. Physiol, p. 47.

4 This solidity of the skin with the Tardigrada,
is one evidence that these animals are more prop-
erly classed with the Arachnoidae, instead of with
the worms whose skin contains no chitine and is,
therefore, quickly dissolved in caustic potass.- See
the analyses of the skin of the earth-worm by Las -

saigne ( loc. cit.), and of that of Ascaris , Meck-
elia , Sabella , Hermione and Nephtys , made by
Loewig and Kdlliker (Ann. d. Sc. Nat. V. 1846,
p. 198).

1 For example, with Epeira, Segestria , Thom-
isus , Argyroneta , Salticus , Sarcoptes , &c.

2 Plumose hairs are very often found with the
Araneae *, and I have found lanceolate scales with
Salticus , and clavate excrescences with the Trom-
bidina •, see Hermann , loc. cit. PI. III. fig. 0 — Y.

3 I am unable to say whether the internal mem-
brane is prolonged at these points into the hollow
excrescences of the skin, or whether the appear-
ances alluded to are not produced artificially when
the outer is separated from the inner layer of the
skin.

§ 298.

THE ARACHNOID AE.

369

moulting, is a layer of colored vesicles and granules, which can be seen
through the skin, giving it the often very beautiful colors which are
observed in many species.

The various divisions of the cutaneous skeleton, of which the number is
quite limited, have been so thoroughly studied in zoology, that they may
well be passed over here without notice.

The Cephalothorax sends off from its inner surface, especially with the
Opilionina, and Araneae, various processes, which serve, as with the Crus-
tacea, as points for the insertion of muscles, and as septa between certain
organs. With the Araneae, they form, at the bottom of the cephalothorax,
a solid horizontal plate, — a kind of internal skeleton, which, before and
behind, is attached to the sternum by two tendinous ligaments. This plate
is deeply indentated on its anterior border, and furnishes points of inser-
tion for the muscles of the extremities, as well as for several other
parts.™

CHAPTER II.

MUSCULAR SYSTEM AND ORGANS OF LOCOMOTION.

§ 298.

The voluntary muscles of the Arachnoidae are of a dirty-yellow color,
and, like those of the Crustacea, are distinctly striated transversely. (1) Their
general disposition agrees, also, with those of Crustacea.™

The principal muscular masses are found in the cephalothorax, for here
arise, not only the muscles of the parts of the mouth, but also those of the
first article of the tactile organs and legs. With those species having an
unarticulated abdomen, the muscles of this part of the body differ from
those of Crustacea. For, directly beneath the skin, is a thin layer, com-
posed of numerous short, riband-like fibres, interlaced in various directions,
and frequently anastomosing with each other.® Moreover, with many spe-
cies, there are, on both the dorsal and the ventral surface of the abdomen,
depressions of the skin, from which pass off small muscular bands, which
penetrate into the interior of the abdomen, and pass among the viscera.

With the Araneae there is, generally, on each side of the ventral median

4 This plate, already recognized by Lyonet (loc.
cit. p. 405, PI. XXI. fig. 26), and by Treviranus
(Bau d. Arach. Taf. II. fig. 23), has been described
more exactly by Wasmann (loc. cit. p. 2, fig.
2-4). A similar, but rudimentary plate, exists,
perhaps, with Phalangium , and, as it lies under
the ventral cord, the muscles have the appearance
of rising from this last ; see Tulk, loc. cit. p. 325,
or in Froriep's neue Notiz. XXX. p. 136.

1 The Tardigrada form an exception in this re-
spect, their muscles being smooth ; see Do y (ire,
loc. cit. p. 336.

2 For the disposition and arrangement of the
muscular system of Scorpionidae and Araneae, see

Meckel , Syst. d. vergleich. Anat. III. p. 47 *, and
for the muscles of Phalangium and My gale, see
Tulk, and IVasmann, loc. cit. The very compli-
cated muscular system of the Tardigrada is quite
apparent from the transparency of these animals ;
see Doyiire, loc. cit. p. 335, PI. XVII.-XIX.

3 This cutaneous layer, already observed by
Treviranus (Verm. Schrift. I. p. 9, Taf. I. fig. 3,
a. n.), and by Brandt (Mediz. Zool. I. p. 88, Taf.
XV. fig. 8, a. a., or Ann. d. Sc. Nat. XIII. p. 180,
PI. IV. fig. 1, a. a.), with Epeira , has been con-
firmed by Tulk (loc. cit. p. 154) with Phalan-
gium, and described in more detail by IVasmann
(loc. cit. p. 8, fig. 7, 8) with My gale.

370

THE ARACHNOID AE.

$ 299.

line, a tendinous ligament, on which are inserted several of these muscular
bands. W) It is very probable that these animals can, by this apparatus,
compress their abdomen in various directions.

§ 299.

The locomotive organs of the Arachnoidae are situated exclusively on the
cephalothorax. They consist of only four pairs of legs, of which the first
may, perhaps, be regarded as the posterior pair of metamorphosed max-
illae.(1>

Some Mites, only, when young, have six feet, and the young of the Pyc-
nogonidae have, also, only four. With Plirynus, and Thelyphonus, the first
pair considerably resembles two multi-articulated tactile organs ; but with
Galeodes, these same organs have wholly the appearance of legs, excepting
they are without claws. With Mygale, the maxillae of the first pair have
the form of feet, and their extremity is not only unguiculated, but also pro-
vided with a tarsus. The other Arachnoidae have usually nails on all their
feet, and, with some, each foot may have four nails.® With many Ara-
neae, the nails have, on their convex side, a pectinated appendage.®

As to the types of the articulations of the legs, they are usually as fol-
lows; first, a movable Coxa; then a short Trochanter ; then a longer,
stiff Femur ; then a Tibia, divided by an articulation into two unequal
parts; and, finally, a Tarsus, composed of a long and a short article. With
the Phrynidae, not only are the first and antenniform pair of feet already
mentioned, different from this type, but the three other pairs have a great
number of articles, each tarsus having four. But the Phalangidae differ the
most, — the tarsi of all the feet having an extraordinary number of articles.
On the other hand, among the lower Arachnoidae, and especially with the
Acarina and Tardigrada, there are species with which the seven articles
just mentioned cannot be easily distinguished, for the articulations are less
in number, or wholly indistinct. With many of these species, some of the
pairs of legs, or even all, are reduced to real foot-stumps. (4) Numerous par-
asitic Acarina have, between the nails, a small organ ( Arolium ,), by which,
as with a sucker, they can attach themselves to foreign bodies.® These
organs are most developed with Sarcoptes and allied genera, which are
without nails, for they here consist of a long, pedunculated disc upon all, or
only upon some of the feet.® With the aquatic Hydrachnea, the swimming
feet have no other peculiarities than that one of their sides is thickly pilose.

4 For these muscles, the cutaneous insertions of
which, with the Araneae, with Chelifer and Pha-
Langium , have been taken by Treviranus (Bau
d. Arach. p. 23, Taf. II. fig. 17-19, Taf. III. fig.
28, and Yerm. Schrift. I. p. 18, 33, Taf. II.) for the
stigmata, see Brandt , Mediz. Zool. loc. cit. p. 88,
Taf. XV. fig. 8, c. c., and Ann. d. Sc. Nat. loc. cit.,
and Wasmann , loc. cit. p. 3. fig. 1, 6, 24.

1 See Dugis, Ann. d. Sc. Nat. I. p. 7, and
Erickson , Entomogr. Heft. I. p. 7.

2 Most usua.ly there are two nails to each foot ;
but Phalangium , Hoplophora , and Damaeus ,
have only one ; while Segestria, Lachesis , and
Clotho , as well as Demodex, Pelops , Zetes , and
Or i Oates , have three, and Emydium and Macro-
biotics have even four.

3 See the figures of Savigny , loc. cit.

4 The articulations are few and indistinct with

all the eight legs of Tyroglyphus and Glycipha-
gus , but with the anterior legs, only, with Sarcop-
tes. The posterior legs of this last genus, and all
of them with the Tardigrada, and with Demodex
folliculorum , are only simple stumps.

5 For example, with Ixodes, Ar gas, Dermanys-
sus , Pteroptus , &c.

3 With Sarcoptes ovis and cati, this arolium is
absent with the penultimate pair of legs ; and with
Sarcoptes equi, with the last pair. With Sar-
coptes cynotis , rupicaprae, and scabiei , it is
wanting with the last two pairs. With Sarcoptes
hippopodes , Glycyphagus prunorum , and Meli-
chares agilis, all the legs have long pedunculated
organs of this kind ; see Hering, Die Kriitzmilben
der Thiere, in the Nov. Act. Nat. Cur. XVIII.
part II. Tab. XLIII.-XLV.

$$ 300, 301.

TIIE ARACHNOIDAE.

371

CHAPTElt III.

NERVOUS SYSTEM.

§ 300.

The grades of development of the Nervous System with the Arachnoidae
are very different, being connected with the divisions of the cutaneous skel-
eton. For, when these last disappear, those of the nervous system belong-
ing to them, and often the ventral cord, are concentrated, as with the
brachyurous Decapoda, into a single ganglionic mass, occupying the ventral
portion of the cephalothorax ; while, if the body is multi-articulate, this sys-
tem resembles that of the macrurous Decapoda. In both cases, with only
a few exceptions, there is a cerebral ganglion situated above the oesophagus,
and connected with the ventral cord by two short commissures surrounding
this canal. From this ganglion pass off nerves to the eyes, and the maxil-
lary palpi or so-called mandibles ; while the first pair of maxillae, changed
into tactile organs, receive their nerves from the anterior extremity of the
ventral cord.

The intimate structure of the nervous system, with the Arachnoidae, con-
sists of primitive fibres much finer, and ganglionic globules much smaller,
than those of Crustacea.® As to the direction and disposition of these
fibres, those of the Scorpionidae almost exactly resemble those of the
Myriapoda.®

§301.

The nervous system is most simple in its organization with the Acarina.
In those 'species where, as yet, it has been found,® it consists only of a
simple abdominal ganglion, from which pass off, from all sides, the peri-
pheric nerves; and, upon the upper surface of which, is detached a simple
transverse band, under which the cosophagus passes. ’

With the Tardigrada, this system is a little more developed, although
the brain is still wanting.® It consists of four ganglia, corresponding to
the four segments of the body, and connected together by double longitudi-
nal commissures. Between each of the ganglia, the commissures are con-
nected by a transverse filament. The nerves which proceed from the
ganglia belong to the muscles; but the first ganglion sends, moreover, in
front, four larger trunks, which are the nerves of sense, and are distributed
to the eyes and palpi.®

1 Hannover , loc. cit. p. 71, PI. VI. fig. 83, 84.

2 See § 271, and Newport , Philos. Trans. 1843,
loc. cit.

1 With many small Acarina, particularly Sar-
coptes and Demodex , no traces of a nervous sys-
tem have been found, notwithstanding the most
careful researches •, but this is not surprising, con-
sidering the minuteness of these animals.

2 Treviranus (Verm. Schrift. I. p. 47, fig. 32)
has investigated the nervous system of Trom-
bidium , and the results he obtained have been

confirmed with this genus and with Limnochares,
by Dujardin (Ann. d. Sc. Nat. III. p. 19). Sub-
sequently, Treviranus (Zeitsch. f. Physiol, loc.
cit. p. 189, Taf. XVI. fig. 7. c.) has also con-
firmed, with Ixodes , this passage of the oesophagus
through the principal ganglionic mass. With
Trombidium, whose ganglion is somewhat reddish,
the cerebral commissure is quite distinct.

3 See Doytre, loc. cit. p. 343, PI. XVII. {Milne-
8ium).

372

THE ARACHNOID AE.

§ 301.

The ventral chain of the Pycnogonidae is composed likewise of four
ganglia, but these, which send off, each, a nerve from its side to the corre-
sponding foot, are contiguous, and the first connects with the ovoid cerebral
ganglion by two lateral commissures.<4>

With the Araneae, the central portion of the nervous system consists of
a large sub -oesophageal ganglion, and another, smaller and above the oesoph-
agus. They are separated from each other only by a narrow fissure
through which the oesophagus passes. The super-oesophageal ganglion,
which is somewhat emarginated in front, corresponds to the brain, and
sends off nerves to the eyes and cheliceres. The sub-cesophageal gan-
glion, situated in the middle of the cephalothorax, sends off’, on each side,
four larger processes, from which arise the nerves of the feet. Its anterior
border supplies, moreover, the nerves of the two palpi; and from its poste-
rior margin pass off two nerves for the abdominal viscera.®

The nervous system of Galeodes,{U) Phrynus, and Thelyphonus,{7) has a
like disposition.

The central mass of the nervous system of the Phalangidae begins by
two conical, contiguous cerebral ganglia, which connect with a sub-
cesophageal, fused ganglion, by two short lateral commissures. This ven-
tral ganglion is composed of a transverse portion, which is situated in the
centre of the cephalothorax, and of two lateral portions which consist, each,
of an anterior or larger, and a posterior or smaller lobe. These lobes send
off nerves to the eight legs, and in front, others to the palpi ; while from
the posterior border of the transverse portion pass off several nerves to the
viscera of the abdomen.®

With the Scorpionidae, the nervous system is very highly developed.
The brain, which is not large, is composed of two spheroidal, super-
oesophageal ganglia fused together. Above, and in front, they send off
nerves to the eyes and the cheliceres ; and below, they connect with the
first ventral ganglion by two short, large filaments, which embrace the
oesophagus. The first ventral ganglion is pretty large, being the result,
probably, of the fusion of several ganglia. It is situated in the middle of
the cephalothorax, and sends nerves to the palpi and to the eight legs. In
the rest of the body there are three ventral ganglia, smaller, and followed
by four others situated in the tail. All these ganglia are connected by
double, longitudinal commissures, and the posterior seven give off, from
each side, two nerves; while from the last ganglion arise also two others,
which, passing backwards, soon unite and extend to the very extremity of
the tail, sending oil' nerves right and left.®

4 Quatrefages, loc. cit., 77, PI. I. fig. la 2'; also
PI. IL. fig. 2, 3 ( Ammothea and Phoxichilus).

5 Treviranus, Ueber d. inn. Bau d. Arach. p.
44, Taf. Y. fig. 45, and Zeitsch. f. Physiol. IV. p. 94,
Taf. VI. fig. 4 5 Lyonet , loc. cit. p. 405, PI. XXI.
fig. 22 *, Brandt , Mediz. Zool. II. p. 90, Taf. XV.
fig. 3, 4, or Ann. d. Sc. Nat. XIII. p. 184, PI. IV.
fig. 4. Dug&s, Ibid. VI. p. 174 ; Grube , loc. cit.
p. 302, and finally Owen , Lectures, &c., p. 255, fig.
109. This last author has represented, in a very,
instructive manner, the nervous system of a My gale
seen in profile.

6 Blanchard, loc. cit. p. 1384.

7 Van der Hoeven, Tijdschrift. loc. cit. IX.
1842, p. 68, and X. 1843, p. 369.

* [ § 301, note 9.] See also Du four (Ann d.
Sc. Nat. XV. 1851, p. 250). This anatomist has
found a fourth abdominal ganglion, situated just

8 The nervous system had already been partially
described by Treviranus (Verm. Schrift. I. p. 38,
Taf. IV. fig. 24) *, but especially, and with full de-
tails, by Talk, loc. cit. p. 324, PI. V. fig. 31.

9 For the nervous system of the Scorpionidae,
see Treviranus (Bau. d. Arach. p. 14, Taf. I. fig.
13, and Zeitschrift f. Physiol. IV. p. 89, Taf. VI.
fig. 1-3, and Muller , loc. cit. p. 60, Taf. I. fig. 5,
7) *, but especially Newport's excellent description
(Philos. Trans. 1843, p. 260, PI. XII.) ; he has
traced, with Androctonus , the nerves of the ex-
tremities even into the tarsal articles and terminal
hooks.*

behind the thoracic mass, from which passes
off a pair of nerves to the pulmonary organs
( Scorpio occitanus). — Ed_.

§ 302.

THE ARACHNOIDAE.

373

§ 302.

A Splanchnic nervous system has been observed with only the higher
Arachnoidae ; but here it is highly developed. The odd stomachic nerve
has been the part most difficult to discover ; it is observed, however, with
some Araneae, — the posterior border of the brain sending off two small
filaments which traverse the central opening of the stomach but unite on
its dorsal surface. a) The Scorpionidae have a similar stomachic nerve which
also arises from the brain by two filaments which have a small ganglion at
the point of their union.®

With the Phalangidae, Araneae, Galeodea, and Phrynidae, the splanch-
nic nerves are very distinct. They arise from the posterior border of the
ventral nervous mass situated in the cephalothorax, and are distributed to
the digestive, respiratory, circulatory, and genital organs, and have, some-
times, ganglia on their course. With Phalangium, there are three of
these nerves arising from the posterior border of the transverse portion of
the ventral mass. The middle one of these nerves divides into two
branches, which dilate into two ganglia connected together by a transverse
anastomosis. From these two ganglia arises a nervous plexus, which is dis-
tributed to the internal genital organs, and to the corium. The lateral
nerves, directly after their origin, likewise divide into two branches, each of
which forms a ganglion ; the external nerves after a shorter, and the inter-
nal after a longer course. The two external ganglia thus formed send fila-
ments to the terminal portion of the genital organs, while those of the two
internal ganglia are distributed to the digestive tube and neighboring or-
gans.® With the Araneae, the Galeodea, and Phrynidae, the posterior
extremity of the principal ventral ganglion sends off two considerable
nervous cords, contiguous, which pass into the abdominal cavity where they
are distributed, radiatingly, to the digestive organs, to the pulmonary sacs,
to the genital organs, and to other abdominal viscera. Sometimes, before
dividing, they unite in a common ganglion. (4)

1 This Nervus sympathicus recurrens was dis-
covered by Brandt , with Epeira ; see Mediz. Zool.
II. p. 90, Taf. XV. fig. 4, d., and fig. 6, c., or in
the Isis, 1831, p. 1105, Taf. VII. fig. 6, b., and Be-
merk. iib. d. Mimdmagennerven, loc. cit. p. 15, or
Ann. d. Sc. Nat. V. p. 94, and XIII. p. 185, PI.
IV. fig. 2, c. This same nerve has been refound by
Grube (loc. cit. p. 302), with other indigenous
Araneae. With My gale , according to Dugds (Ann.
d. Sc. Nat. VI. p. 175), there are, instead of two
simple filaments, two lateral ganglionic net-works,
from the brain to the stomach.

2 See Newport , loc. cit.*

3 See Treviranus , Verm. Schrift. I. p. 38, Taf.

IV. fig. 24, and Talk, loc. cit. p. 325, PI. V. fig.
31, 33.

4 This ganglion has been observed by Trevira-
nus (Bau d. Arach. p. 45, Taf. V. fig. 45), with the
indigenous Araneae, and by Dugis (Ann. d. Sc.
Nat. VI. p. 175), with My gale. According to
Brandt (Mediz. Zool. II. Taf. XV. fig. 3, and
Ann. d. Sc. Nat. XIII. p. 185, PI. IV. fig. 4), this
ganglion is wanting with Epeira, and Trevi-
ranus (Zeitsch. f. Physiol. IV. p. 95), has vainly
sought for it in a Brazilian spider. Blanchard
(loc. cit. p. 1384), has found it with Galeodes , and
Van der Hoeven (Tijdsch. X. p. 370), with Thely -
phonus.

[ § 302, note 2.] See also Dufour , loc. cit. p. 251. — Ed.

32

374

THE ARACHNOID AE. §§ 303, 304, 305.

CHAPTER IV.

ORGANS OF SENSE.

§ 303.

The multi-articulated antennae with which the Crustacea and Insecta are
endowed, are absent with the Arachnoidae, or, more properly speaking, they
are changed into prehensile and masticatory organs. (1) 2

The palpi, which are absent with only a few Arachnoidae,® must be re-
garded as the principal seat of the sense of Touch. These tactile organs
always receive two considerable nerves arising from the anterior extremity
of the ventral ganglionic mass.® A very delicate sense of touch exists,
also, in the extremity of the feet, which are well supplied with nerves ;
and, for this object, the feet of the Opilionina and Phrynidae have the
form of multi-articulated antennae.

With the Araneae, this point admits of no doubt, for these organs (the
feet) are especially used in the formation of the web.

§ 304.

Although we must grant to the Arachnoidae the sense of Taste, and that
of Smell ; and although many facts show that they have the sense of Hear-
ing highly developed, yet, at present, nothing satisfactory has been discov-
ered either as to the locality or the structure of the organs which are the
seat of these senses.®

§ 305.

The organs of Vision of the Arachnoidae consist always of simple eyes
(Stemmata); but among the lower Arachnoidae, there is a complete series,
namely, the parasitic Mites, and allied groups, which are entirely deficient
in these organs. (1)

The stemmata of the Arachnoidae have exactly the same organization as
the simple eyes of the Crustacea. They are composed of a simple and
convex cornea, of a spherical lens, and of a concavo-convex, vitreous body,
which is surrounded by a Retina. Each of these eyes is enveloped, before
and behind, by a pigment tunic corresponding to the Chorioidea ; its color

1 See § 306. Latreille (Il£gne anim. IV. 1829,
p. 207), has regarded these mandibles as trans-
formed antennae, but usually they have been con-
sidered as the first pair of maxillae. This view
of Latreille, is the correct one, since the nerves of
those organs do not arise from the abdominal
ganglia, but directly from the brain, as those of
the antennae of Crustacea and Insecta.

2 These palpi are wanting with Pycnogonum ,
Phoxichilus , Phoxichilidium and Pallene ; ^ee
Savigny , M6m. loc. cit. I. PI. V. fig. 3 ; Johns
ton , Mag. of Zool. and Bot. I. PI. XIII. fig. 1-8 ;
Milne Edwards , Hist. Nat. d. Crust. PI. XLI.
fig. 6. With the Scorpionidae, as well as with

Obisium , Chelifer , Phrynus , and Thelyphonus ,
the palpi are forficulate, and are used as prehensile
organs.

3 See Treviranus , Zeitsch. f. Phys. IV. p. 94,
Taf. VI. fig. 4, No. 4 (a Brazilian spider), and
JJoyire, loc. cit. p. 349, PI. XVII. tig. 1, n. a.
( Milnesiurn ).

l According to analogy, the sense of taste, with
the Arachnoidae, is seated probably at the entrance
of the oesophagus.

1 The eyes are wanting with Demodex , Sar-
coptes , Pteroptas , Dermanyssus , Gamasus ,
Thyroglyphus , Glycyphagus, Acarus , Argos ,
Ixodes , &c.

§ 805.

THE ARACHNOIDAE.

375

is very variable, and, in front, it terminates between the lens and the vitre-
ous body by a ring which resembles an Iris. TV hen two of these stemmata
are contiguous, the pigment tunic is common between them.®

The number, the situation, the disposition, and the direction of the eyes,
present so many variations, that they have been used by zoologists to char-
acterize the genera. Chelifer , Erythraeus, Smaridia, Tetranychus, Arre-
nurus , and the Tardigrada, have two of these organs on the anterior por-
tion of the back, while with many Oribatea, they are lateral and anterior.
With Trombidium, there are two eyes also, but they are situated directly
above the first pair of legs, on clavate peduncles.® With the Pycnogo-
nidae, and with Obisium, there are four eyes situated on the first segment of
the body ; there are the same number, also, with Bddla, Rhyncholophus,
Eyla'is, Ataz, Diplodontus, Hydrachna, and Limnochares , situated on the
anterior part of the back.2 3 (4)

With the Opilionina, there are two median, larger, and two lateral,
smaller eyes. The first of these are situated on a tubercle, and their cor-
neae face right and left.® With Galeodes, there are six eyes on the
anterior border of the first segment of the body ; of these, the middle or
largest pair is directed upwards ; another, situated in front of these last,
forwards ; and the remaining pair, inserted above the anteriorlegs, later-
ally. ® The Araneae have, usually, eight eyes ; only a. few have but six.®
These eyes, always situated on the cephalothorax, are generally of differ-
ent sizes with the same individual, -and are either grouped symmetrically
upon the anterior median line of the cephalothorax, or scattered on its
lateral border.® The dorsal eyes are directed upwards, and the marginal
ones, forwards or laterally.

The disposition and direction of these organs are conformable with the
animal’s mode of life ; some species watch their prey in crevices, fissures,
or tubes ; while others remain motionless in the centre of their webs, or
lurk from side to side, — a kind of life requiring them to look in all direc-
tions. The color of the pigment of the eyes is based also upon the same
relations ; for, with the diurnal species, it is green, reddish, or of a

2 For the structure of the eyes of Arachnoidae,
see Soemmering , De ocul. hom. animal, sect, hor-
izont. p. 74, Tab. III.; and Gaede , Nov. Act. Nat.
Cur. XI. p. 338 ( Mygale ) ; but especially Mul-
ler, Zur. vergleich. Physiol, d. Gesicht-sinn. p. 316,
Taf. VII. fig. 8-11, or Ann. d. Sc. Nat. XVII.
1829, p. 234, PI. XII. fig. 1-4 ( Androctonus and
Galeodes). Brants (Tijds. &c. V., or Ann. d. Sc.
Nat. IX. 1838, p. 308) has confirmed Muller'' s ob-
servations for the eyes of Buthus and Mygale ;
but he observed, also, tubes situated behind the
vitreous body, and analogous to those of the eyes of
Crustacea and Insecta. Muller , however (Arch.
1838, p. 139), has been unable to find them, but he
observed that the fibres of the optic nerve, after
having entered the eye, are separated by the long
filamentoid pigment bodies ; and he adds, that
these fibres should not be confounded with the
vitreous cones of the faceted eyes, the first becoming
opaque in alcohol, while the second preserve their
transparency.

3 These pedunculated eyes, already figured by
Degeer (loc. cit. p. 57, Taf. VIII. fig. 15, y. y.),
have been described by Hermann (loc. cit. p. 19,
PI. III. fig. E. G.), as Qculi inferi ; see, also,
Treviranus , Verm. Schrift. I. p. 49, fig. 31, 33,
34, o. o.

1 "With Bdella , the eyes are wholly lateral. With
the llydrachnea, above named, they are united

in pairs, so that each pair would easily be taken
for a single ejre. With Atax , Diplodontus , and
Hydrachna , the two pairs of eyes are widely sep-
arated. But with Eyla’is , and Limnochares ,
they are closely approximated. With the young
of these aquatic mites, their position is often differ-
ent (Dug Us, Ann. d. Sc. Nat. I. p. 144, PI. IX.
X.).

TEagner's attributing (Lehrb. d. vergleich.
Anat. p. 431) compound eyes to certain Hydrach-
nea, is due, without doubt, to his regarding as
such the approximated simple eyes. Dujardin
(Ann. d. Sc. Nat. III. p. 19), however, affirms
that Penthaleus has a single eye, composed of
eight to ten facets, while some of the species of
Oribates and Molgus have only a single stemma
situated on the back.

5 See Treviranus , Verm. Schrift. I. p. 24, Taf.
II. fig. 10. The two lateral eyes are wanting with
many Opilionina. According to Tulle (loc. cit. p.
326, PI. V. fig. 32), there is a pair of muscles in-
serted on the two middle eyes, by which their con-
tents can be displaced.

6 See Muller , Zur vergleich. Physiol. &c. p.
332, Taf. VII. fig. 11.

7 There are six eyes with Scytodes , Segestria,
Dysdera , and Uptiotes.

8 See Savigny , Descript, de l’Egypte, loc. cit.
PI. I.-VII. and tValc/cenaar , loc. cit. P1..I.-IV., &c.

376

THE ARACHNOID AE.

§ 306.

brownish black, as with the other Araclinoidae ; but with the nocturnal
spiders, it is replaced by a membrane which has a splendid lustre.® With
the Phrynidae, there are also eight stemmata, of which two are situated on
the middle of the cephalothorax, and the remaining six form a triangle
composed of three on each of its sides.

With the Scorpionidae, the eyes are the most numerous. There are two
large eyes on the middle of the cephalothorax, then a row of from two to
five smaller on each side of its anterior border.

The number of optic nerves depends, usually, upon that of the eyes.
But the Scorpionidae form an exception in this respect ; for their brain
sends off, at the side of the two median optic nerves, two other nerves,
common, and belonging to the two rows of marginal stemmata, but which
do not divide until they have reached these organs.9 (10) On account of the
usually deep position of the brain, the optic nerve is generally of consid-
erable length ; but the Pycnogonidae alone differ in this respect from the
other Arachnoidae, for, with Phoxichilus, the four eyes are situated directly
on the brain, and, with Ammothea, this last sends off, as a common optic
nerve to the four eyes, a large, short prolongation. (11)

CHAPTEll Y.

DIGESTIVE APPARATUS.

§ 306.

The entrance of the digestive canal is surrounded by very variable
organs, but, with all, the Mandibles are always wanting. The organs usually
called such are only antennae metamorphosed into prehensile and masti-
catory parts. This is shown not only from the cerebral origin of their
nerves, but by the fact that they, or more properly the Cheliceres, never
act, like the mandibles of the other Arthropoda, in a horizontal direction.
Most of the Arachnoidae live on liquid food, and, therefore, the basilar
article of the maxillae is more or less abortive, and is rarely used in mas-
tication, while the succeeding articles are changed into a usually very
large tactile or prehensile palpus.

In general, the organization of the parts of the mouth with the Arach-
noidae may be divided into the following five types :

1. With the Tardigrada, there are real organs for suction. These con-
sist of a kind of sucker, situated on the end of a fleshy proboscis which can
be retracted into the head. On each side of this proboscis there are two
stylets (teeth) which, by means of a special muscular apparatus, can be
protruded into the former. (1>

2. With most of the Acarina, the two cheliceres are sometimes forficu-
late or unciform, sometimes cultrate or styliform, and by their use, these

9 Dugis , Ann. d. Sc. Nat. VI. p. 175. 11 Quatrefages , loc. tit. p. 77, PI. I. fig. 1%

10 Treviranus , Zeitscli. f. Physiol. IV. p. 92, 2a*.

Taf. VI. fig. 3 ; and Muller , Zur vergleich. Phys- 1 See Doyire, loc. cit. p. 319, PI. XIII.-XV.
iol. &c. p. 321, Taf.* VII. fig. 10, or Ann. d. Sc.

Nat. XVII-. p. 238, PI. XVII. fig. 3.

§ 306.

THE ARACHNOIDAE.

377

small animals can pierce or cut as may be required. These cheliceres are
free, or lodged in a sheath out of which they may be protruded ; some-
times they are covered, above or below, by a frontal or chin-like pi'ocess.
In a few instances, these processes are united, forming a proboscis out of
which the cheliceres may be protruded.® The first pair of maxillae,
which are inserted on the sides of the cheliceres, are wholly unfit for masti-
catory organs, and, being destined for tactile parts, they have the form of
palpi. These palpi are sometimes multi-articulated, sometimes uni-articu-
lated, and, from their various modifications, have received the names of
Palpi rapaces , anchorarii, fusiformes , Jiliformes, antemiiform.es , vaivae-
formes, and adnati.{&)

3. The Oribatea, which, from their herbivorous nature, hold a distinct
place, not only among the Acarina, but also among the Arachnoidae in gen-
eral, are distinguished also for the organization of their buccal organs.
Their cheliceres are protractile, and the first pair of maxillae, situated
under them, forms a complete masticatory apparatus, their basilar article
being developed at the expense of the rest into a large denticulated
piece. The other articles form only a very short palpus.®

4. The Pycnogonidae, Opilionina, Pseudoscorpii, Galeodea, and Scor-
pionidae, all, have tri-articulated cheliceres. Under these last are situated
the first pair of maxillae which have no masticatory character.® With
the Scorpionidae, and Pseudoscorpii, they are long-forficulate, while, with
the Galeodea, the Pycnogonidae and Opilionina, they are antenniform.
With the Phalangidae, only, there is observed on their basilar article, a
hairy, obtuse appendage, comparable to a rudimentary maxilla.® With
the Scorpionidae, the two basilar articles of the pincers are so approx-
imated by their flattened internal surfaces, that they may well be used for
the bruising of soft animal substances.®

5. With the Phrynidae, and Araneae, the cheliceres have the form of
bi-articulated, unciform antennae. The basilar article of these so-called
mandibles is always very thick, and the terminal article consists of a
small, very sharp hook.® When at rest, this last lies folded on the inter-

2 For the cheliceres of the Acarina, see the de-
scriptions and figures of Hermann , Dugds, and
Dujardin,{ loc. cit.). These organs are forficulate
with the Acarea, Garaasea and Bdellea ; see Du-
jardin , Observ. au Microsc. PI. XVII. fig. 10, 11
(Acarus). They are unguiculate with Trombidi-
um, Erythraeus , Smaridia , Atax , and EyLais ;
see Treviranus , Verm. Schrift. I.Taf. V. fig. 29
( Trombidium ). They are styliform with the Ix-
odes, Tetranychus , Rhyncholophus , Rhaphig-
nathus , and Hydrachna. The frontal prolonga-
tion is regarded by some authors as an under lip.
It is found with Dcrmanyssus and Rhaphigna-
tkus ; while, with Ixodes , it belongs to the chin,
and thus forms an under lip. With Smaridia ,
and Sarcoptes , the cheliceres are encompassed by
a kind of tube •, see Dujardin (Observat. &c. PI.
XVII. fig. 1-4 {Sarcoptes). With Ixodes , the
cheliceres are cultrate and denticulate on their
external borders ; see Savigny , Descript, de
l’Egypte, PI. IX. and Audouin , Ann. d. Sc. Nat.
XXV. PI. XIV. The brevity and inequality of
these organs, as noticed by Audouin with Ixodes
erinacei , were due to the circumstance that they
were imperfectly and unequally protruded from
their sheath.

3 This classification of the palpi belongs to Du-
gis ; see Ann. d. Sc. Nat. I. p. 11.

32*

4 I have satisfied myself of the presence of
horny denticulated maxillae, fitted for mastication,
with HopLophora , Pclops , Zetes , Oribatcs , Da-
rn aeus, and with other Oribatea.

5 Some Pycnogonidae form the only exception in
this respect. With Pariboea , the cheliceres are
simple, bi-articulate and clavate 5 but with Ende'is ,
Pycnogonum, and Phoxichilus , they are wholly
wanting •, see Philippi , in fViegmanii's Arch.
1843, I. Taf. IX. fig. 1-3 ; also Savigny , Johns-
ton, and Milne Edwards , loc. cit.

Savigny , Mem. &c. I. PI. VI. fig. 2, d.

7 It is well known that the Scorpionidae and
the other rapacious Arachnoidae, merely suck
their prey ; but it is said that Galeodes devours
completely the insects which it has caught, seizing
them with their cheliceres, and eating them piece
by piece. During these processes each chelicere
acts separately ( Hutton , Ann. of Nat. Hist. XII.
1843, p. 81, or Froriep's neue Not. XXVIII. p.
49). The Phalangidae have probably the same
habits, for fragments of insects which they have
eaten are found in their digestive canal (Tw/Ar,
loc. cit. p. 248).

8 See Roesel , loc. cit. Taf. XXXVII., and Sa-
vigny, Descript, de l’Egypte, PI. I.-VIII., also Ly-
onet , loc. cit. PI. XIX. XXI.

878

THE ARACHNOID AE.

* 207.

nal side of, or underneath the basilar article. It is erected when the
animal, for defence, or for the seizure of its prey, inflicts a poisonous
wound; and, for this purpose, the excretory duct of a poison-gland
opens at the apex of each of these hooks/i) * * * * * * * 9 * *' The first pair of maxillae is
changed, with the Araneae, into very long tactile, and with the Phrynidae,
into prehensile organs. Their basilar articles form two upwardly directed
prominences, which are contiguous at their bristly, internal borders, and
thereby cover the entrance of the oral cavity. (l0) As the Araneae bruise,
by means of these prominences, their prey which they have seized and
taken into their mouth, these parts may be regarded as rudimentary
maxillae.

The entrance of the Oral cavity is surrounded, with most Arachnoidae,
by a soft, unequal border. This may be regarded, in part, as an upper and
under lip, and partly as a tongue. &1> The orifice and cavity of the mouth
are often provided with small hairs pointing inwards, among which are
sometimes observed horny ridges, which serve, probably, as teeth. The
Araneae have this peculiarity, that their large oral cavity has a groove on
the median line of the palate, which is continuous into the oesophagus/12'
Its lateral borders may be so approximated that it is changed into a canal.
This apparatus is certainly very serviceable to these animals in sucking
their prey, after it has been punctured repeatedly, and taken into the
mouth.

With very many Arachnoidae, the food, before reaching the proper
digestive tube, traverses a very short oesophagus/13'

With the Araneae, this canal is geniculate, of a horny consistence, and,
at the point where it enters the stomach, it presents a prismatic muscular
enlargement on which is inserted a large muscle arising from the centre
of the dorsal shield and passing through the central opening of the
stomach/14' This serves probably as a sucking apparatus during the pre-
hension and deglutition of food/15' With the Tardigrada, the oesophagus
terminates also by a muscular apparatus of this kind, which, with Macro-
biotus, and Emydium, is spheroidal, and with Milnesium, cylindrical/16'

- § 307.

The Intestinal canal of the Arachnoidae is formed after two different

types.

1. With the Tardigrada, Aearina,
dae, and Araneae, the stomach has

i) See § 315.

10 See Treviranus, Bau d. Arach. Taf. II. fig.

14-16, r., and Brandt , Mediz. Zool. II. Taf. XV.

fig. 9, 18, b.

11 With the Araneae, and Scorpionidae, the

entrance of the mouth has a tumid, pilose upper

lip. With the Opilionina, there are several such

tumefactions, but with the Pycnogonidae, the oral

orifice is prolonged, snout-like, between the max-

illae.

12 See Lyonet. loc. cit. p. 401, PI. XXI. fig. 4,

5, and Dugds, Ann. d. Sc. Nat. VI. p. 178.

13 With the Aearina, Pycnogonidae, and Araneae.

Quatrefages (Compt. rend. XIX. 1844, p. 1152)

thinks he has observed a ciliated epithelium in the

Pycnogonidae, Opilionina, Solpugi-
a greater or less number of caecal

oesophagus of the Pycnogonidae; but, subsequently,
he found that he was deceived, and that vibratile
organs were wanting here as with all the Arthro-
poda.

14 Brandt , Mediz. Zool. I. p. 89, Taf. XV. fig.
6, b., or Ann. d. Sc. Nat. XIII. p. 183, PI. IV. fig.
2. b.

15 This suctorial apparatus appears to have been
well described and understood by Wasmann (loc.
cit. p. 10, fig. 13, i. m.) ; but, already before this,
Lyonet (loc. rit. p. 402, PI. XXI. fig. 4, C I) E.)
had rightly perceived it : while Brandt (Med.
Zool. II. p. 87) had taken it for an os hyoides.

10 Doydre, loc. cit. p. 322, PI. XIU.-XV.

§ S07.

THE AKACHNOIDAE.

S79

diveriiculi, of the most varied form and size. It is continuous into a short,
small intestine, which passes, in a straight line, to the anus situated usually
at the posterior extremity of the body. Before reaching this point, the
intestine has, usually, a dilatation bounded by a constriction, which may be
regarded as a rectum, or better, perhaps, as a cloaca. With the Tardi-
grada, the stomach is oblong and occupies a large portion of the body. It
is divided throughout by numerous constrictions into many irregularly dis-
posed caeca.®

With the Acarina, whose anus is placed nearer the middle of the belly,
there are, nearly always, three short caeca at the anterior part of the
stomach, and two, longer and more or less constricted, in the lateral regions
of the abdomen. With some species of parasitic Mites, these appendages of
the stomach are bifurcated.® With the Pycnogonidae, the stomach is short,
but has five pairs of very long caeca, some of which penetrate into the two
cheliceres, and others into the eight long legs, even to the extremity of the
tibiae.® With Galeodes , also, these appendages penetrate the legs, and-
the base of the cheliceres and palpi.1 2 3 (4) With the Phalangidae, the stomach
is spacious and has thirty appendages of varied size. Thus, at its upper
part, there are four rows of short caeca, and, upon the sides, three pairs,
very long and extending over nearly the whole length of the visceral cavity ;
the middle pair of these last has, moreover, short sacculi.® With the Araneae,
the stomach is situated in the cephalothorox, and presents a very remark-
able disposition. At the posterior extremity of the thoracic cavity, and
directly behind the sucking apparatus, it is divided into lateral halves
which extend arcuately in front, and, uniting, form a ring from which are
given off laterally five pairs of caeca extending towards the points of inser-
tion of the legs and palpi.

The intestine arises from this annular stomach, opposite the sucking
apparatus. It traverses the abdomen on the median line, and terminates,
before reaching the anus, in a cloacal dilatation.®

2. With the Phrynidae,® and Scorpionidae,® the intestinal canal is
very simple compared with that just described. It consists of a straight

1 Doyire, Ibid. p. 324, PI. XV.

2 See Lyonet , loc. cit. PI. XIII. fig. 11, 12 ;
Dug&s, loc. cit. I. PI. I. fig. 27. II. PI. VII. ( Ery -
thraeus , Dermanyssus and Ixodes) ; also, Tre-
viranus, Zeitsch. f. Physiol. IV. p. 189, Taf. XVI.
Ixodes has dichotomous stomachic appendages, of
which the posterior, at the. extremity of the body,
curve first downwards, then forwards with a long
course. These various caeca of the Acarina often
appear, especially when filled with food, clearly de-
fined, through the skin. But when empty, they
are frequently overlooked in the small species,
from the tenuity of their walls. However, I have
always succeeded, even with the smallest Oribatea,
in distinguishing the walls of the intestine, especially
when it contained food. I must, therefore, consider
as wholly erroneous, the opinion recently advanced
by Dujardin (Ann. d. Sc. Nat. III. p. 14, or
Compt. rend. loc. cit. p. 1159), that the food eaten
by the Acarina does not pass through a distinct
digestive tube, but is freely effused in the interstices
of the viscera.

3 Milne Edwards , Ilist. Nat. d. Crust. III. p.
531, and Quatrefages , loc. cit. p. 72, PI. I. II.

4 Blanchard , loc. cit. p. 1384.

6 Ramdohr , Abhandl. ub. d. Verdauungswerk.
p. 205, Taf. XXIX. ; Treviranus , Verm. Schrift.
I. p. 29, Taf. III., and Tulk , loc. cit. p. 246, PI.
IV.

6 For the annular stomach of the Araneae, and
on which, with Tegenaria , Treviranus (Bau d.
Arach. p. 30, Taf. II. fig. 24, v. b.) has found only
four caeca, see Brandt , Mediz. Zool. II. p. 89, Taf.
XV. fig. 6, or Ann. d. Sc. Nat. XIII. p. 182, PI.
IV. fig. 2, or Isis, 1831, p. 1105, Taf. VII. fig. 6 •,
also Otoen, Lectures, &c., p. 257, fig. 110; and tVas-
mann , loc. cit. p. 11, fig. 17, 18. According to
this last observer, the four pairs of stomachic caeca,
with Mygale, bend downwards to the base of the
eight legs, in order to pass into the thorax where
they ramify and interanastomose.

With Argyroneta , and some species of Epeira ,
according to Grube (. Muller's Arch. 1842, p. 208),
the lateral halves of the stomach are not united in
a ring at their anterior extremity, but are only con-
tiguous.

With the Araneae, the walls of the stomach con-
tain finely-granular cells which, by reflected light,
have a milky aspect, and secrete perhaps a kind
of gastric juice.

7 Van der Iloeven , Tijdschr. &c. IX. p. 68
( Phrynus ).

8 Meckel , Beitriige, loc. cit. p. 107, Taf. VII.
fig. 13 ; Treviranus , Bau d. Arach. p. 6, Taf. I.
fig. 6, and Muller , loc. cit. p. 45, Taf. II. fig.
22»

380

THE ARACHNOIDAE.

$ 308.

tube, of nearly equal size throughout, without a stomachic dilatation and
without caeca, which opens by an anus at the posterior extremity of the
body.®

§ 308.

The Salivary glands exist with, perhaps, all the Arachnoidae ; for, they
are found even in many of the lower forms, where their presence would be
least expected. With the Tardigrada, there are on each side of the suck-
ing apparatus, large, lobulated glandular tubes, which appear to be organs
of this nature, although their outlets have not yet been distinctly traced. (1>
With the Oribatea, there is at the anterior extremity of the body, a pair
of similar tubes, but simple and colorless, which extend to the mouth,
and have undoubtedly a salivary function.®

With Ixodes , these organs are extraordinarily developed, consisting of
two large masses of vesicles situated on the sides of the anterior part of the
body, and opening by short ducts into two multiramose excretory canals.
These last, whose walls are traversed by a solid spiral filament, open into
the buccal cavity at the base of the lip-like process.®

With the Araneae, a slit in the upper iip leads into a cavity situated
above the palate, and at the base of this cavity is a transparent, glandular
mass, which, very probably, secretes the saliva ; this flows up through the
slit in question, and moistens the substances from which the animal ex-
tracts its food.® As salivary organs should also be considered the two
pairs of glandular tubes, which, with the Scorpionidae, are situated on the
sides of the anterior part of the body, and extend forwards to open into
the oesophagus.®

With the Araneae, and Scorpionidae, there is a Liver distinct from the
digestive tube, which, for a long time was regarded as an adipose mass.
With the Tardigrada, Acarina, Pycnogonidae, and Opilionina, the walls of
the stomachic appendages are of this nature, for they are glandular and com-
posed of granular and usually yellowish-brown cells.® With the Araneae,
the brown or dirty-yellow liver is very voluminous, filling a large portion
of the abdominal cavity, and enveloping most of the other viscera.

At first sight, it appears to be a compact mass, but, further examined,
it is found composed of numerous multiramose, closely-aggregated caeca.
The walls of these are thick, and crowded with hepatic cells, and they open
into the digestive canal near its middle by four short hepatic ducts.®

9 With the Scorpionidae, the anus is situated on
the penultimate caudal segment.

1 See Doytre , loc. cit. p. 321, PI. XHI.-XV.

2 I have seen these glandular tubes with Hoplo-
phora , Zetes , and Oribates.

3 The salivary glands of Ixodes ricinus resem-
ble exactly the botryoidal ones of many of the In-
secta.

The secretory vesicles of the saliva are filled with
transparent nucleated cells and surrounded by
numerous ramified tracheae with which it is im-
possible to confound the excretory ducts of these
glands ; for with these last the spiral turns of thin
filament are very wide apart, while, in the tracheae,
the spiral windings are very close together.

4 This glandular apparatus has been seen by
Wasmann (loc. cit. p. 8, fig. 16) with Mygale /
I have found it also with other Araneae.

5 See Muller , loc. cit. p. 52, and Mcwport ,
Philosoph. Trans. 1843, PI. XV. fig. 39. f*

6 With the Tardigrada, Acarina, and Opilionina,
at least, I have seen, distinctly, hepatic cells in
the walls of the stomachic appendages. See also
Doyire , loc. cit. p. 327, PI. XV.

7 Treviranus (Bau d. Arachnid, p. 30, 47, Taf.
II. fig. 24, dd., and Taf. V. fig. 47) had already
observed the communication between the liver and
the digestive organs. The remaining points in the
structure of this organ have been rightly estimated
by Dugis (Ann. d. Sc. Nat. VI. p. 179), Urube
(loc. cit. p. 299), and Wasmann (loc. cit. p. 13, fig.
17, m. n., 20-22). See also Owen , Lectures, &c.,
p. 258, fig. 110, i. i.

§ 309.

THE ARACHNOIDAE.

381

With the Scorpionidae, the liver is also very large, and composed of many
lobes. It occupies the two sides of the abdominal cavity even to the base
of the tail, and closely encompasses the intestine, the heart, and the genital
organs. The ramifications of the biliary canals traverse, in groups, the
parenchyma of this liver, and the bile is poured into the intestine by five
pairs of short, excretory ducts, equally, but very widely separated from
each other.® *

n CHAPTER VI.

CIRCULATORY SYSTEM.

§ 309.

With many Arachnoidae, the circulatory system consists only of a Heart
or an articulated dorsal vessel. With the higher forms, there is, in addi-
tion, a system of more or less developed blood-vessels; while with the
lower species, such as the Tardigrada, the Acariua and the Pycnogonidae,
not only all these vessels, but the heart, also, is absent. There is, there-
fore, in these last, no regular circulation, but the nutritive fluid fills all the
interstices of the body, and, by the aid of the muscular movements and the
contractions of the intestinal canal, is transferred in an irregular manner
hither and thither in the visceral cavity and in the extremities. (1)

The Blood of the Arachnoidae is entirely colorless, and has a slightly
milky aspect only when in considerable quantities. It contains a few
granular blood-cells of a pretty regular, spheroidal form, and some very
small, isolated granules, derived perhaps from broken blood-cells.®

8 See Meckel, Beitr. &c. p. 107, Taf. VII. fig.
13, 15 ; this author has seen four pairs of hepatic
ducts. See, also, Trevi/anus, Bau d. Arachn. p. 8,
Taf. I. fig. 6, A. v., and Muller , loc. cit. p. 35, 46,
Taf. II. fig. 22, D. D.j finally Newport , Philosoph.
Trans. 1843, PI. XIV. fig. 32.

1 C. A. S. Schultze (in his memoir “ Macro-
biotus Hufelandii ”) thinks he has observed blood-
vessels in the Tardigrada ; but neither Doytre
(loc. cit. p. 310) nor I have been able to find
them. For the interstitial circulation of the Pycno-
gonidae, see fyuatrefages , loc. cit. p. 76. Van

* [ § 308, end.] See, for some researches upon
the hepatic organs of the Arachnoidae by means of
chemical agents, and the positive determination

Beneden has observed, in the extremities of these
animals, regular blood-currents produced appar-
ently by contractile membranes at the base of the
legs ; see Institut. No. 627, or Froriep's neue
Notiz. XXXVII. p. 72.

2 For the blood of the Arachnoidae, see Wagner ,
Zur vergleich. Physiol, d. Blutes, Heft. I. p. 27, fig.
11 ( Scorpio europaeus ) ; Horn , Das Leben des
Blutes, p. 10, Taf. I. fig. 12 (Tegenaria domes-
tica ), and Doytre , loc. cit. p. 309, PI. XV. fig. 5
( Tardigrada .)

thereby of the nature of the alleged hepatic append-
ages of the alimentary canal of these animals, .
Will, Muller's Arch. 1848, p. 507. — Ed.

382

THE ARACHNOIDAE.

§ 310.

§310.

With the Arachnoidae, the circulatory organs, when present, are disposed
in the following manner :

With the Phalangidae, they consist only of a Dorsal Vessel, which is
three-chambered, and attenuated at both extremities/1*

With the Araneae, the dorsal vessel is fusiform, and has many constric-
tions. It is situated principally in the abdomen, being attached to its dor-
sal wall by triangular transverse muscles. This heart, which extends also
into the cephalothorax, sends off from each extremity and from its sides,
many ramified, vascular canals, which are certainly Arteries.

The two of these last arising directly behind the peduncle of the abdo-
men, are distributed to the pulmonary sacs, while those following penjtrate
chiefly the liver. All these vessels gradually disappear in the parenchyma
of the body, and the blood, after its effusion, continues to circulate in the
lacunae, and, without the intervention of veins, is returned to the heart, or
more properly into the blood-reservoir which corresponds to the dorsal
sinus of the Crustacea. Thence it enters the heart through its lateral,
valvular openings.®

The vascular system is most highly developed with the Scorpionidae.
For, here, not only is there an articulated Heart and Arteries, but also a
Venous system.® The cylindrical heart whose walls contain transverse
and longitudinal muscular fibres, is retained in place between the dia-
phragm of the cephalothorax and the last abdominal segment, by several
transverse triangular muscles. It has eight chambers whose size dimin-
ishes from before backwards. At each extremity it is prolonged into an

1 See Tulk , loc. cit. p. 249, PI. IV. fig. 17, H.,
and Treviranus , Verm. Schrift. I. p. 31, Taf. III.
fig. 16, k., and fig. 18.*

2 For the vascular system of the Araneae, see
Meckel , in his translation of Cuvier's Lemons
d’Anat. comp. Th. IV. p. 261 ; Treviranus, Bau
d. Arach. p. 28, Taf. HI. fig. 28-31, also his Verm.
Schrift. I. p. 4, Taf. I. fig. lj Gaede , Nov. Act. Nat.
Cur. XI. p. 335, Tab. XLIV. fig. 3 ( Mygale ), and
Brandt , Mediz. Zool. II. p. 89, Taf. XV. tig. 16,
17. See also Dugis (loc. cit. p. 181), who has been
unable to find the venous system with the Araneae,
but, at the same time, traced the heart even into
the cephalothorax. \Vasmann (loc. cit. p. 16, fig.
24), on the other hand, affirms that he has observed,
with Mygale , venous trunks which entered the

* [ § 310, note 1.] Blanchard (loc. cit. Ann.
d. Sc. Nat. XII. 1849, p. 333) has extended our
knowledge of the circulatory system of this family.
The dorsal vessel terminates behind in a small ves-
sel which runs to the extremity of the body. In
front it passes into an artery of considerable size,
which passes under the brain and sends off small
• branches to the oesophagus. At the base of this
aorta the ophthalmic artery is given off, which
bifurcates behind the eyes. From this portion of
the heart also pas3 off branches to the stomach.
This naturalist declares the existence here of his
peritrachean system, which, together with the heart,
he says he has injected through the lacunae. —
Ed.

heart above the points of origin of the arteries.
The analogy between the heart of Crustacea and
of Araneae has been especially pointed out by
Straus (Consid£rat. &c. p. 345, and Traite d’Anat.
comp. II. p. 251), and since confirmed by Grant
(Outlines, &c., p. 452) and Grube (loc. cit. p.
300). |

3 Treviranus (Bau d. Arachn. p. 9, Taf. I. fig.
7), and Muller (loc. cit. p. 38, Taf. II. fig. 22),
were acquainted with only the heart and larger vas-
cular trunks of the Scorpionidae ; but Newport
has given of the blood system of these Arachnoidae
a complete and masterly description accompanied
with very beautiful figure^*, see Philos. Trans.
1843, p. 286, PI. XIV. XV., or Froriep's neue
Notiz. XXXIX. p. 81, fig. 38-40.

f [ § 310, note 2.] According to Blanchard
(loc. cit.), the blood, in the Araneae, passes to the
respiratory organs, which it penetrates by a kind
of infiltration ; from the lacunae of the walls of the
lungs it is taken to the heart by means of the pul-
mono-cardiac vessels which have hitherto been
taken for arteries. There are six pairs with Epeira
diadema. But with those Araneae which have
both lungs and tracheae, such as Segestria , Dys-
dera, &c., there is some modification, although the
arterial system resembles that of the Araneae
essentially pulmonary } the heart is smaller and
has fewer chambers, and the true arteries seem to
lose their importance and give place to the peritra-
chean system of circulation. — Ed.

§ 310.

THE ARACHNOIDAE.

383

arterial trunk. The anterior of these arteries very soon ramifies, and dis-
tributes blood to the feet, the pincers, the cheliceres, and to all the organs
in the cephalic extremity. Two of its branches, bending downwards, em-
brace the oesophagus, and then join in a large common vessel called the
Supra-spinal artery, which lies upon the ventral cord and accompanies it to
the caudal extremity, giving off, in its course, numerous lateral branches. (4>
The posterior arterial trunk is distributed in like manner to the posterior
extremity, and gives off, right and left, numerous branches. The middle
chambers of the heart send off, each, laterally, shorter arteries, which are
distributed to the neighboring organs. 'Beside these arteries of the muscles
and viscera, these animals have, also, a special Visceral artery, arising from
the anterior arterial trunk before it divides into the two branches which
form the supra-spinal artery. The visceral artery runs backwards towards
the digestive tube, and sends branches to the liver.® The terminal rami-
fications of these various arteries are directly continuous, it is said, with a
venous system/6’ In this last may be noticed, especially, a Sub-spinal
vein, by which the blood is carried to the pulmonary sacs; thence to be
borne to the heart by special vessels. These last open, probably, into a
sinus, from which the blood passes into the heart through lateral openings,
two of which exist in each of its chambers.!

4 This supra-spinal artery had been seen, it
would appear, by Muller (loc. cit. p. 62, Taf. I.
fig. 5, r. r.), but he took it for a ligament.

■r> According to Newport , this visceral artery,
which is simple with Androctonus , is divided into
two trunks with But/ius.

6 Newport speaks in his memoir of various an-
astomoses occurring between the arteries and veins
with Scorpio. But, as he nowhere describes pre-

* [ § 310, note 6.] In regard to the question of
capillaries with the Scorpionidae, a remark of
Blanchard (loc. cit.) may be given. lie says, “ I
have proved with an entire certainty that the blood
is distributed in all the cavities of the body, as with
all the Articulata, and that it is conveyed to the
lungs simply by means of the lacunae. Most of the
vessels which arise from the sides of several of the
chambers of the heart have appeared to me to be

cisely this point, and has not distinctly indicated it
in his plates otherwise so beautiful, I demur admit-
ting that, with the Scorpionidae, the arteries pass
directly into the veins, and therefore, that these
animals have a system of capillary vessels. This
direct communication between these two systems
does not exist with the other Arachnoidae, neither
with all the other Arthropoda in general.*

pulmono-cardiac vessels, wholly analogous to those
we have described with the Araneae.” — Ed.

t [ § 310, end.J For further details on the cir-
culatory system of the Arachnoidae, see the memoir
quoted above of Blanchard. This naturalist has
sought to extend his doctrine of the peritracliean
circulation, to the different sections of the Arach-
noidae. — Ed.

384

THE ARACHNOIDAE.

$$ 311, 312.

CHAPTER VII.

RESPIRATORY SYSTEM.

§ 311.

r

The higher Arachnoidae respire by tracheae, or by lungs ; but in the
lower, namely, the Tardigrada,® the Pycnogonidae,® and some parasitic
Acarina,® no traces of respiratory organs have yet been found. With
these animals therefore the respiration must be cutaneous.

Many Acarina, the Opilionina, the Pseudoscorpii and the Solpugidae,
breathe by tracheae, while the Araneae, the Phrynidae and the Scorpio-
nidae breathe by lungs. On this account, these animals have been divided,
in zoological systems, into the Arachnidae tracheariae and puhnonariae.
But this classification is valueless, since it has been shown that the Araneae
possess both lungs and tracheae.

§ 312.

With the Acarina, the Tracheae are exceedingly tenuous, and it is only in
the larger species that the spiral filament of these organs can be observed.
They arise usually by a simple tuft from two stigmata which are sometimes
concealed between the anterior feet, as with the Hydrachnea, the Oribatea,
and the Trombidina, sometimes very apparent above the third pair of legs,
as with the Gamasea, and sometimes behind the last pair of legs, as with
the Ixodea.®

With the Hydrachnea, which live in the water and never come to the
surface to take in air, the tracheae possess, probably, the power to extract
from the water the air necessary for respiration.®

With the Pseudoscorpii, there is, on the ventral surface of the two first
abdominal segments, a pair of lateral stigmata, with four short but large
trachean trunks from which arise numerous unbranched tracheae spread-
ing through the entire body.® With the Solpugidae, whose tracheae

tracheae of the Acarina, see, moreover, Dujardin
(Ann. d. Sc. Nat. III. p. 16, or Compt. rend. loc.
cit. p. 1160). It will be difficult, I think, to prove
the assertion of Dujardin , that, with these animals,
the trachean system serves exclusively for the act
of expiration, inspiration being performed wholly
by the skin.

2 Duffia (Traits d. Physiol. II. p. 549) is cer-
tainly right in placing the tracheae of the Hydrach-
nea in the category of Branchiae tracheales , which
are so widely spread with the aquatic larvae
of Insecta (see below).

3 According to Audouin (Ann. d. Sc. Nat.
XXVII. 1832, p. 62), the tracheae of Obisium are
ramified, a statement which I have been unable to
verify. It has already been stated that the scar-
like fossae on the abdomen of Chelifer have been
erroneously taken for stigmata ( § 298, note 4).
The tracheae of the Pseudoscorpii are so easily
seen by the microscope that it is incomprehensible
how anatomists should have remained so long

1 See Doyere , loc. cit. p. 316.

2 See Quatrefages , loc. cit. p. 76.

3 Demodex , Sarcoptes , Acarus , &c.

1 With Trombidium , there arise two simple
and very distinct trachean tufts from the two
stigmata situated behind the second pair of legs
( Treviranus , Verm. Schrift. I. p. 47, Taf. VI. fig.
32, t. t.). These tracheae do not proceed directly
from the stigmata, but from two large, short trunks
unobserved by Treviranus.

With Gamasus , and Uropoda , there are given
off, from the two ramified trachean tufts, two un-
branched tracheae which, remaining of the same
size, describe a slightly arcuate course along the
lateral borders of the cephalothorax and terminate
in caeca at the base of the parts of the mouth. The
two lateral stigmata of Ixodes have been described
by Lyonet (loc. cit. p. 288, PI. XIV. fig. 3, 5),
Treviranus (Zeitsch. f. Physiol. IV. p. 187, Taf.
XV. fig. 2,/. /.), and Audouin (Ann. d. Sc. Nat.
XXV. p. 419, PI. XIV. fig. 2, q. r. s.). For the

A

§ 312.

THE ARACHNOIDAE.

385

ramify through the whole body like those of insects, there are three pairs
of stigmata. (4> With the Phalangidae, the trachean system is highly
developed, arising from two stigmata concealed under the coxae of the
posterior legs, each of which has a horny valve. The two large trunks
given off from these stigmata, run obliquely to the cephalic extremity; they
intercommunicate by a transverse anastomosis, and give off, in all direc-
tions, numerous branches which are spread over the abdominal viscera, and
penetrate even the palpi and legs.®

With many of the Araneae, there are, on the under surface of the abdo-
men, two orifices which lead into two pulmonary sacs, beside two other
openings belonging to the trachean system. With Segestria, Dysdera ,(6>
and Argyroneta,{1) there arise from these two stigmata two large trunks
surrounded by a kind of horny trellis-work. From the extremity of these
trunks are given off innumerable, very small tracheae, which are un-
branched and without the spiral filament. They are disposed in tufts, and
are distributed, some in the abdomen, and others in the cephalothorax,
penetrating even to the extremity of its members. With Salticus, and
Micryphantes ,<8> the two stigmata are situated at the posterior extremity
of the body, far removed from the pulmonary sacs, and send off, directly,
two tufts of unbranched tracheae, which are distributed exclusively to the
abdominal viscera.® There is, with the other Araneae, a trachean
system, very imperfect it is true, which has hitherto been overlooked by
anatomists. Directly in front of the spinnerets, there is, with most species,
a transverse fissure difficult to be seen, which leads into a very short
trachean trunk. From this trunk are given off four simple tracheae
which, singularly, are not cylindrical, but are flattened, riband-like, and
without a trace of a spiral filament ; these extend, with a gradual attenua-
tion, to the base of the abdomen. These riband-like, silvery tracheae are
composed of a thin, but solid, homogeneous membrane, which is enveloped
by a soft, transparent pellicle corresponding to a peritoneum. The air
received into these organs is separated into as fine portions as that of the
lungs. These tracheae differ therefore, prominently, from those of the
other Arachnoidae.(10)

ignorant of their existence, and even lately, that
Tulk (Annals of Nat. Hist. XV. p. 57) should
have failed to see them with Obisium.

4 See Muller , Isis, 1828, p. 711, and Milne Ed-
wards, Regne anim. Illustr. Arachnides, PI. II.

o Treviranus , Verm. Schrift. I. p. 32, Taf. IV.
fig. 19, and Tulk , loc. cit. p. 327, PI. V. fig. 33.

6 Duges, in “ Le Temps,” 1835, No. 1942,
Feuilleton, Acad. d. Sc. Stance du 9 Fevrier, or
Froriep's neue Notiz. XLIII. p. 231, or Ann. d.
Sc. Nat. VI. p. 183, and Rt^gne animal, Arach-
nides, PI. III. fig. 4, V. fig. 4. See also Owen ,
Lectures, &c., p. 259, fig. 112.

7 Qrube , loc. cit. p. 300, and Menge , loc. cit. p.
22, Taf. I. fig. 6-14.

8 Menge, loc. cit. p. 23, Taf. I. fig. 15.

9 I have had an opportunity to satisfy myself of
the existence of this interesting trachean system
with Segestria, Argyroneta, Salticus , and Micry-
phantes. I should also add that the principal
trunks are flattened, and that the contained ah' is

finely divided, while that in the cylindrical tra-
cheae given off from these trunks, forms a continu-
ous column.

10 I have found this trachean system with
Epeira, Tetragnathns , Drassus , Clubiona,
Tlieridion, Lycosa , Diomedes and several
others. I have been unable to perceive it in
individuals escaping from the egg. Thomisus
viaticus is the only species in which the four
flattened trachean trunks are ramified, and thus
serves as the passage to the most highly developed
trachean system of Salticus. By direct light,
they appear black, and thus it is possible that they
may have sometimes been taken for urinary canals.
But this error is unnecessary, for these last vessels
burst from the slightest pressure and effuse granu-
lar contents, while the tracheae under such treat-
ment become transparent, their contained air
making its escape, and when the pressure is with-
drawn they resume their black color.*

[ §> 312, note 10.] See also for these anomalous
tracheae, Blanchard (loc. cit. Ann. d. Sc. Nat.
XII. 1849, p. 345), who regards them as only

elongated pulmonary sacs ; but especially Leuc -
kart (Ueber den Bau und die Bendeutung der sog.
Lungen bei den Arachniden, in Siebold and" Kolli-

386

THE ARACHNOIDAE.

§ 313.

§ 313.

The Lungs of the Arachnoidae consist of round sacs situated near the
lower surface of the abdomen and communicating, externally, by transverse
fissures. Their internal surface has numerous thin solid lamellae, triangu-
lar or rhomboidal, and connected together like the leaves of a book. By
reflected light these lamellae have the same silvei’y, lustre as the tracheae,
although, seen by direct light, they appear of a deep-violet, nearly black
color. Each of these is formed by a membranous fold, between the two
leaves of which the air enters from the general cavity of the lung and is
divided into very minute portions. No traces of blood-vessels have been
found in these Pulmonary lamellae. It is therefore very probable that the
blood of the pulmonary arteries is effused into the parts surrounding the
lungs, and in this way bathes the lamellae. a)

With the Scorpionidae, the four anterior segments have, each, on their
under surface, a pair of stigmata. These animals have eight pulmonary
sacs, in each of which there are twenty fan-shaped lamellae.® The genus
Pkrynits has only two pairs of pulmonary sacs, the stigmata of which are
placed between the first and second, and the second and third abdominal
segments. But each sac has eighty lamellae.® With the Araneae, there
are only two lungs occupying the base of the abdomen. The number of
their lamellae is considerably less than in the preceding groups. But with
the Mygalidae only, there is a second pair of lungs directly behind the first.
The place occupied by these organs, is indicated, with the Araneae, by a
triangular horny plate, at the posterior border of which is a stigma.*4’

1 These organs, with which no motions have been
discovered, have been called Branchiae by many
Zootomists. But the name of Lungs is very ap-
propriate since the respiration is a€rial and not
aquatic.

2 For the lungs of the Scorpionidae, see Meckel ,
Translat. of Lemons d. Anat. comp, of Cuvier , Th.
IV. p. 291 ; Treviranus , Bau d. Arach. p. 7, Taf.
I., and Beobacht. aus d. Physiol, p. 25, fig. 40-42 ;
Mailer , Isis, 1828, p. 708, Taf. X. fig. 1-3, and in
Meckel's Arch. loc. cit. p. 39, Taf. II. fig. 11-13.
Muller has very correctly, aud in the above-men-
tioned manner, understood this respiratory appara-
tus, while, on the other hand, Treviranus and
other anatomists, think that the air, instead of
entering between the leaves of the pulmonary
lamellae, passes over their external surface, and
that the blood penetrates between the two plates
composing the leaves. Newport (Philos. Trans-

ker's Zeitsch# 1849, I. p. 246) who, contrary to
Blanchard. , advances the view that these organs
are only a form of tracheae, infra-formed, and
which are without the spiral filament, because
their simple, unbranched condition does not re-
quire, like the ramose tracheae, a spriug-like
structure, to prevent them from collapsing. This

act. 1843, p. 295, PI. XIV.) is probably mistaken in
saying that unnucleated cells and a very fine
capillary net-work exist between these plates, and
that the net-work arises from a branch of the pul-
monary artery situated on the free border of each
lamella.

3 See Van der Hoeven , Tijdsch. loc. cit.

4 The lungs of the Araneae have been studied
by Meckel (Translat. Lemons d’Anat. comp, of
Cuvier , loc. cit. p. 290), Treviranus (Bau d.
Arachn. p. 24, Taf. II. and Beobacht. &c. p. 29, fig.
43-47), Gaede, Nov. Act. Nat. Cur. XI. p. 335,
(My gale) ; but especially by Muller (Isis, 1828, p.
709, Taf. X. fig. 4r-6). See also Menge, loc. cit.
p. 21, Taf. I. fig. 6-9. I am unable to say by
what means the blood returns to the heart, whether
by a direct course, or, more or less circuitously
through the interstices of the parenchyma, for
there are no veins.

view put forth together with the general doctrine
that the pulmonary sacs of the Arachnoidae are,
likewise, but modifications of the tracheal type,
has many facts deserving the attention of anato-
mists, and especially the developmental relations
of the spiral thread a3 observed in the embryos of
these animals. — Ed.

§ 314.

THE AR.ACHN OIDAE.

387

CHAPTER VIII.

ORGANS OP SECRETION.

I. Urinary Organs.

§ 314.

With most Arachnoidae, there are small, usually multiramose, glandular
tubes, which open into the cloaca. By their structure and the nature of
the fluid they secrete, they exactly resemble the Malpighian vessels of the
Insecta, and like them, also, they have, for a long time, been regarded as
hepatic organs; but now, they are known to be positively those of an
urinary nature. The urine is usually accumulated in the cloaca, and con-
sists of a troubled, dirty-white liquid, rarely reddish; and, by direct light,
is found to hold in suspension innumerable dark molecules.

These organs appear to be absent with the Tardigrada* and Pycnogonidae.
But, on the other hand, they are easily observed with many Acarina, where
they consist of simple or ramose white tubes, situated between the append-
ages of the stomach.® With the Plialangidae, there are two pairs of
urinary canals which wind between the stomachic caeca.® With the
Araneae, these organs are numerous, multiramose, and of a white oi
reddish color. Their very small branches penetrate between the different
portions of the liver, and end in two principal trunks or ureters, which
open into a cloaca provided with a kind of diverticulum.® With the
Scorpionidae, the organization in this respect is quite similar, and the
canals, ramified in various ways, enter, some the interstices of the hepatio
lobes, while others surround the digestive canal. They pour their product
into the cloaca by two ureters which are situated back of the biliary
canals.®

1 I have discovered without trouble, these
canals with the Ilydrachnea, Gamasea, Trombi-
dina, and Ixodea. Treviranus (Zeitsch. f. Phys-
iol. IV. p. 189, Taf. XVI. fig. 8, n. n.) had already
observed their insertion into the cloaca with Ix-
odes. With Ixodes ricinus , where they are
simple and flexuous, I have seen them ascend
even to the anterior extremity of the cephalo-
thorax •, this is entirely so with Ixodes ameri -
caiius. The canals, which with Nigua, Treviranus
(loc. cit. fig. 7, g. g.) has regarded as salivary or-
gans, are certainly only the anterior extremities of
the urinary vessels. The two species of Ixodes
just mentioned have their cloaca filled with a
white urine.

2 See Treviranus , Verm. Schrift. I. p. 31, Taf.
III. fig. 16, 17. Tulk (loc. cit. p. 249, PI. IV. fig.
17) who has been unable to trace these canals to
their points of insertion on the intestine, has taken
a portion of them for salivary organs.

3 Ramdohr (loc. cit. p. 208, Taf. XXX. fig. 2),
and Treviranus (Bau d. Arach. p. 30, Taf. II.
fig. 24) were only imperfectly acquainted with the
urinary canals of the Araneae. They have been
more exactly described by Brandt (Media. Zool. II.
p. 89, Taf. XV. fig. 6, 17, or Ann. d. Sc. Nat. XIII.
p. 183, PI. IV. fig. 2, 3) j but see, especially, fVas-
Tnann , loc. cit. p. 17, fig. 17, 21-23 (My gale). In
most species, the urine is of a dirty-white color $
but with Mygale , it is reddish. In several indi-
viduals of a large species of Mygale preserved in
alcohol, I have found, in the ureters, hard, reddish
concretions which Dugis (Ann. d. Sc. Nat. VI. p.
180) hrtd already observed. Treated with nitric
acid and ammonia, I obtained purpuric acid.

4 See Treviranus , Bau d. Arach. p. 6, Taf. I.
fig. 6, and Muller , loc. cit. p. 47, Taf. II. fig. 22.
This last anatomist says that these glandular canals
communicate with the heart, but he has probably
confounded them with the blood-vessels.

388

THE ARACHNOID AE.

§ 315.

II. Organs of Special Secret io?is.

§ 315.

Very many Arachnoidae have Poison-glands, the product of which is
excreted through the extremity of a hollow claw. With the Phrynidae, the
Araneae, and some Acarina, there are two such glands in communication
with the terminal hooks of the cheliceres. They have been often taken for
salivary organs. With the Trombidina, there are, on each side of the
cephalothorax, two small, flexuous, colorless, glandular tubes, which, at
their anterior extremity, are dilated, each, into a cylindrical, thin-walled
poison-reservoir. From this reservoir arises a long, narrow canal, which
runs to the cheliceres. (1) 2 3 * * * With the Araneae, the poison-apparatus consists
of two tubes, often a little curved, and surrounded by a layer of flattened,
spiral, muscular fasciculi.® These two glands are situated at the base of the
cheliceres, extend more or less into the cephalothorax,® and, in front, be-
come suddenly attenuated, forming a narrow excretory duct which termi-
nates at the apex of the hollow claw of the cheliceres.® With the Scor-
pionidae, this apparatus is situated in the last caudal segment ; it consists
of two oval vesicles, whose excretory ducts open at the apex of the sting
situated on the end of the tail. These two glands ai'e surrounded by a
layer of flat, circular, smooth, muscular fasciculi.®

With the Araneae, there is another and very remarkable secretory appa-
ratus, — the Silk organs. Its product is a viscous, transparent liquid which
hardens quickly on exposure to the air, forming threads. It escapes by
three, rarely by two pairs of spinnerets, situated behind the anus.® The
glands which secrete it are composed of transparent nucleolated cells, and
are of very variable form and disposition, but always situated in the midst
of the abdominal viscera. About five kinds of these glands may be dis-
tinguished, although not always simultaneously in the same individual.
The threads have probably different qualities, according to the glands from
which they are secreted.

The genus Epeira, containing all these five kinds of glands, will serve as
the type for their description. There are observed :(7) 1. Small pyriform

follicles, aggregated in groups of hundreds, and having short excretory

1 The two poison-glands of the Trombidium ho-
loscriceum, and Rhyncholophus phalangioides ,
have the form of a ring with a small opening.
Treviranus (Verm. Schrift. I. p. 48, Taf. VI. tig.
34) lias described only very imperfectly these
glands with the first mentioned of these animals *,
and not having seen their excretory ducts, he took
them for salivary glands. Duges (Ann. d. Sc.
Nat. III. p. 10), on the contrary, perceived their
true relation to the cheliceres.

2 It is remarkable that these muscular fasciculi
present such different histological characters. I
have seen them distinctly striated with Lycosa ,
Drassus , Tegenaria and Micryphantes. They
are smooth with Epeira , Thomisus , Clubiona
and My gale ; with Salticus , they present obscure
transverse lines, so that I am undecided whether
they belong to the first or to the second of these
categories.

3 With Mygale , these glands are entirely con-

ceiled in the basilar article of the cheliceres.

•1 Treviranus, Bau d. Arachn. p. 31, Taf. II.

fig. 21, 22 ; Lyonet , loc. cit. p. 397, PI. XX. fig.

1G, 17 •, Brandt , Mediz. Zool. II. Taf. XV. fig. 6,
or Ann. d. Sc. Nat. XIII. PI. IV. fig. 2 •, and
Wasmann, loc. cit. p. 19, fig. 25, 26. For the in-
timate structure of these glands, see Meckel, in
Muller's Arch. 1846, p. 35.

3 Muller, in Meckel's Arch. loc. cit. p. 52, Taf.
I. fig. 7, 8. Serres (loc. cit. p. 90) regards the
portion of these glands which is surrounded by
muscular fibres, as a reservoir of poison, and that
this last is secreted by innumerable glandular folli-
cles enveloping the muscular layer. In fact, with
Scorpio europaeus, I have seen this layer covered,
externally, with a stratum of cylindrical cells.

6 The Mygalidae have two pairs of these papillae,
or spinnerets, instead of six, the usual number.

7 I speak here upon the careful investigations of
//. Meckel ( Muller's Arch. 1846, p. 50, Taf. III.
fig. 40-19). For the older descriptions, see Tre-
viranus, Bau d. Arach. p. 41, Taf. IV. V., and
Verm. Schrift. I. p. 11, Taf. I. fig. 4 ; and Brandt,
Mediz. Zool. II. p. 89, Taf. XV. fig. 5, or Ann d.
Sc. Nat. XIII. p. 184, PI. IV. fig. 5.

§ 315.

THE ARACHNOIDAE.

389

canals, which are interlaced in a screw-like manner, and open at the six
spinnerets;® 2. Six long, flexuous tubes, which gradually enlarge into as
many pouches, and are then continuous, each, into an equally long excre-
tory duct which forms a double loop ; 3. Three pairs of glandular tubes
similar to the preceding, but which open externally through short excre-
tory ducts; 4. Two groups of multiramose follicles, whose pretty long
excretory ducts run to the two upper spinnerets ; 5. Two slightly ramified
caeca, varicose at intervals, and which terminate, by two short excretory
ducts, in the middle spinnerets.

Most Araneae have three pairs of spinnerets, that is, papillae in the
form of an obtuse cone ; the middle pair of these is composed of two, and
the anterior and posterior pairs, of three articles. The apex of these
papillae defines the passage of the thread, and is surrounded by stifl’
bristles and hairs, and dotted with numerous small, horny tubes, which are
only prolongations of the excretory ducts. Each of these tubes is com-
posed of two pieces ; one, basilar and thick, the other, terminal and very
small, and through the orifice of which the web-liquid escapes in the form
of a very delicate thread.® The number of these tubes varies according
to the species, the age, and the sex.(10) Those belonging to the unbranched
glands are distinguished from the others by their size. With some species
of Cluhiona and Drassus , there are, beside the usual six spinnerets, two
others, composed of a single article and joined together. This fourth pair
is situated on the belly, forward of the others, and is connected with a
kind of comb ( Calamistrum ) attached to the metatarsus of the two poste-
rior legs.(11)

With Phalangium, there is an S-shaped glandular tube situated on the
digestive canal, and ending at both extremities by a narrow duct. Its
nature is yet unknown ; and although the outlet of these excretory ducts
has not been discovered, yet as this apparatus is found only with males, it
may well be supposed to have some connection with the genital functions. (12)

With some Acarina, there are certain phenomena indicating that these
animals have special secretory organs, whose product, like the web-liquid,
is hardened on its evacuation. Thus, with some species of the genus
Uropoda, there is formed, by a substance of this kind, a peduncle situated
at the posterior part of the abdomen, and by which these animals fix them-
selves to insects. This stalk, dilated disc-like, was taken formerly for an
organ of suction. (13> Many species of Hydrachna fix, by a kind of glue,

8 My gale has only this one kind of glands 5 they
form four groups, situated immediately at the base
of the spinnerets.

9 The spinnerets and terminal tubes have al-
ready been very exactly figured by Leeuwenhoek
(loc. cit. p. 326, fig. 5, 6), and by Roesel (loc. cit.
Taf. XXXVIII. fig. 4). See also Lyonet , loc. cit.
p. 387, PI. XIX. fig. 6-12 •, JVasmann, loc. cit. p.
20, fig. 31-34, and H. Meckel , loc. cit. p. 54, Taf.
III. fig. 43-45.

10 There are more than a thousand of these
tubes on the spinnerets of Epeira •, with Tcgena-
ria , there are about four hundred \ with Cluhiona
and Lycosa , three hundred ; with Segestria , one
hundred, and their number is even less with the
small spiders ; see Blackwell , Transact, of the
Linn. Soc. XVIII. 1841, p. 219, and Ann. of Nat.
Hist. XV. p. 221, and Menge , loc. cit. p. 24.

11 This pair of accessory spinnerets is found, ac-

33*

cording to Blackwell (loc. cit.), with Clubiojia
atrox , Drassus viridissimus , parculus and exi-
guus.

12 See Treviranus, Verm. Schrift. I. p. 37, Taf.
III. fig. 17, h., and Tulk, loc. cit. p. 252, PI. IV.
fig: 21.

13 See Degeer , loc. cit. p. 52, Taf. 1 II. fig. 16,
and Dugis , Ann. d. Sc. Nat. II. p. 30 ( Uropoda
vegetans). The peduncle is more or less long and
often attached to the hardest parts of the Coleop-
tera. Its formation is connected with some meta-
morphosis of these animals, and is without doubt
due to a secretion produced by some glandular ap
paratus opening near the anus. This view ap-
pears, at least, more natural than that advanced
by Dugis (loc. cit. p. 30), and adopted by Dujar-
din (Compt. rend. loc. cit. p. 1160), that this pe-
duncle is formed by the feces hardening after their
escape from the anus.

390

THE ARACHN OIDAE.

$ 316.

the anterior portion of their body on aquatic plants, and in this position,
wait the completion of their moulting. <14) The secreting organs of this
substance have not y<^t been discovered.

CHAPTER IX.

ORGANS OF GENERATION.

§ 316.

All the Arachnoidae reproduce by a sexual generation, and their male
and female genital organs are situated upon different individuals. The eggs
are fecundated in the genital organs of the females, and the males have
often copulatory organs of a very singular character. The Tardigrada form
an exception in this respect, being hermaphrodites, and wanting the copula-
tory organs.

In general, the genital organs of the Arachnoidae are composed of the
following parts. The ovaries or testicles are always double, but sometimes
blended together on the median line. They are situated in the abdomen,
and have two excretory ducts, which usually open at a common genital ori-
fice at the base of the abdomen, or under the thorax. The ovaries, when
filled with eggs, have always a botryoidal aspect. Only a few species
have an ovipositor or a penis. The excretory ducts of both the ovaries
and the testicles sometimes have appendages which, with the females,
serve to receive the sperm, or to secrete a viscous substance for enveloping
the eggs ; and which, with the males, represent an epididymis or the sem-
inal vesicles. Quite often, the males differ from the females in a special
modification of their clieliceres, their palpi, or some of their legs. When
this is the case, these organs serve, during copulation, to hold the females,
or play the part of a penis.

The eggs of the Arachnoidae are spheroidal, rarely oval,(1) and composed
of a smooth chorion enclosing a vitellus consisting of vesicles filled with a
colorless and, also, often highly-colored fat, in the midst of which is con-
cealed the germinative vesicle. The germinative dot is sometimes simple,
sometimes composed of a group of small granules.® The eggs of Lycosa,
Thomisus, Diomedes, Salticus and Tegenaria, are remarkable ; for, beside
the germinative vesicle, they contain, before being filled with the vitellus,
a peculiar, round, finely-granular, solid nucleus.®

14 According to Duff is (Ann. d. Sc. Nat. I. p.
170), Hydrachna cruenta , adult, before moulting,
bores into aquatic plants by means of its oral or-
gans. But I have seen it fixed, also, upon smooth
glass walls, with the parts of its mouth enveloped
in a kind of cement.

1 The eggs are oval with the Oribatea and Scor-
pionidae.

3 The germinative dot is simple and flattened
with Scorpio , Thomisus , Theridion, Micry-
phantes , Lycosa , Phalangium , Obisium , Trom-
bidium , Hydrachna , Ixodes. Oribates , Bdella , &c.
It is composed of a group of granules with Epeira ,

Clubiona and Salticus ; see Waffner . Prodom.
&c. loc. cit. p. 8, Tab. I. fig. 11 {Epeira).

3 This nucleus which appears to contain a cen-
tral nucleolus, is distinguished, with direct light,
by its dirty-yellow color, and it has always ap-
peared to me that there were detached successive-
ly from its surface several layers of granules
which mixed with the albumen, without the nucle-
us diminishing in size. At all events, this nucleus
plays an important part in the development of the
eggs, for it appears very early, and does not disap-
pear until quite late. It has also been observed

§316,

THE ARACHNOIDAE.

391

The lower Arachnoidae produce only a small number of eggs at a time,
but these are often of a size disproportionately large to that of the
animal. <4)

As yet, only very incomplete researches have been made on the elements
of the Sperm. It appears, however, that the spermatic particles differ
considerably in the various groups. Those of the Tardigrada have the
cercarian form ; those of the Scorpionidue, on the contrary, are simply
filamentoid. But both kinds have very active movements which are
suspended by the contact of water.® The Sperm of the Araneae always
contains spherical or reniform motionless corpuscles.® With the Aca-
rina, the spermatic particles are motionless and of most varied forms.®

by Wittich (Observ. quaed. de Aranearum ex ovo
evolut. Dissert. Halis, 1845, fig. 1, A.).*

4 With the Tardigrada, the eggs are very large,
as are also those of Oribates , Sarcoptes and De-
modex.

5 See Doyire , loc. cit. p. 354, PI. XVI. fig. 5
( Macrobiotics ), and Kblliker , Schweiz. Denkschr.
VIII. loc. cit. p. 25, Taf. II. fig. 16 ( Scorpio euro-
paeus). I have observed that the characteristic
movements of the spermatic particles ceased in-
stantly from contact with water, and that the par-
ticles themselves became twisted and doubled.

6 With Tegenaria , Salticus , Lycosa and The-
ridion , the spermatic particles have the form of
round cells, while those of Micryphantes and
Clubiona are reniform or semilunar. They are
formed in groups in the mother-cells. With Tege-
naria, a round nucleus is easily distinguished in the
spermatic particles. With Lycosa , this nucleus is
oblong, curved and attached to the wall of the cell*,
and this led me at first to think these cells were
the spermatic particles in their first stages of de-

* [ § 316, note 3.] The development and struc-
ture of the eggs of Araneae have recently been
carefully studied by Wittich (Die Eustehung des
Araclmideneies iin Eierstocke, die ersten Vor-
gitnge in deraselben nach scinem Verlassen des Mut-
terkorpers *, in Muller's Arch. 1849, p. 113), and
by J. V. Carus (Ueberdie Entwickelung des Spin-
neseies, in Siebold and Kblliker' s Zeitsch. II.
1850, p. 97). The structure of the ovary of these
animals is no less beautiful than singular *, it re-
sembles a bunch of grapes enclosed in a common
capsule. The eggs are developed, each, on the ex-
tremity of a pedicle which is attached to the main
stem or rachis. The details of the development of
the ova are briefly as follows : On the extrem-

ity of the pedicle appears a delicate vesicle, or cell,
which contains a nucleated cell. This nucleated
cell is the germinative vesicle, with its dot, and
does not increase so rapidly in size as the vesicle
in which it is contained ; but this last dilates and
expands, and minute cells appear in the liquid,
lying between its membrane and the germinative
vesicle. These newly-formed cells constitute the
vitellus 5 and when the ovum is completely formed,
it consists of vitellus in which is concealed the
germinative vesicle with its dot. In a word, the
ovum is here formed as elsewhere, except that it is
developed on the extremity of a pedicle. In regard
to the peculiar bodies mentioned above by Siebold ,
as found in the vitellus, their presence aijd struc-

velopment, and that their definite form would be cer
carian. But I quickly abandoned this idea when I
found the same form in the seminal receptacle of
the females, where, evidently, the spermatic parti-
cles cannot be present except in their perfect state.

1 With Trombidium , Zetes , Oribates , and
Hoplophora , the spermatic particles are developed,
as I have satisfied myself, under the from of very
small, rigid corpuscles, in very large ceils. With
Bdella , they are produced in a similar manner, but
are fusiform. With other Acarina they are found
of remarkable forms. Thus, in the testicles of the
Ilydrachnea and Gamasea, I have observed round
masses of cuneiform bodies, at the larger extremity
of which there was an oblong granular spot. I
have also satisfied myself that these motionless
spermatic particles of such large size are preceded
in their development by round nucleated cells. In
the testicles of Ixodes ricinus, I have seen count-
less transparent staff-like bodies, pretty long and
large, motionless, but swollen at one of their ex-
tremities when placed in water.f

ture have been observed by both Wittich and
Carus ; they are composed of concentric layers
around a nucleus. Of their nature and function
nothing is known. — Ed.

t [ § 316, note 7.] I have studied the develop-
ment and nature of the spermatic particles of the
Araneae and Acarina, but with results different
from those above mentioned. With the first of
these, they are developed, as usual, in special
daughter-cells, and invariably consist of an arcuate
staff, to which is attached a short but very, very
delicate tail ; indeed, this tail is so tenuous that
only the best and highest microscopic powers can
bring it out. It escaped the watchful eyes of Wag-
ner and Leuckart , and led them to adopt errone-
ous views of the formation of these bodies (see
Art. Semen , Cyclop. Anat. & Phys. fig. 374).
With the Acarina, the particles have the same
form and character, but are much more minute and
difficult of examination. It would appear from the
description given above by Siebold , that he must
have taken for spermatic particles the peculiar
granule-like bodies found in the sperm of the
Araneae. These bodies are very hydroscopic, but
are homogeneous, and although I could make out
nothing further as to their structure, yet it is evi-
dent that they are wholly different from the true
spermatic particles, and cannot be considered as
either undeveloped or modified forms of these last.
— Ed.

392

THE ARACHNOID AE.

$$ 317, 31S

I. Hermaphrodite Arachnoidae.

§ 317.

The Tardigrada have only a single, but large, ovarian tube, applied on
the posterior half of the digestive canal and opening into the cloaca. This
last which is only a dilatation of the rectum, receives, also, two lateral,
narrower, seminiferous tubes, together with the excretory orifices of a
pyriform seminal vesicle. With Milnesium, Emydium, and Macrobiotus
ursellus, the eggs are surrounded by a smooth chorion, and deposited in a
solid epidermis which is detached during the moulting, — so that all the
eggs are finally contained in this envelope. But the other species of
Macrobiotics shield their eggs in another manner, by surrounding each
with a very solid, granular capsule. (1)

II. Female Arachnoidae.

§ 318.

The female organs of the Acarina consist of two ovarian sacs, the ovi-
ducts of which open in a common vulva situated in the middle of the belly,
or further forwards on the thorax, sometimes between, sometimes behind
the last two pairs of legs.(1> With many of these animals, the oviduct
opens into a protractile ovipositor by the use of which the eggs are lodged
under the epidermis of plants or animals.® A great number of Mites

1 For the genital organs of the Tardigrada, see
Doyire, loc. cit. p. 350, PI. XIII. XIV. XVI.
Goeze ( Bonnet , Abhandl. aus d. Insekt. 1773, p.
374), and O. F. Muller (in Fuessly , Arch. d. In-
sektenkunde, lift. VI. p. 27, Taf. XXXVI. fig. 4, 5)
had already observed that the Tardigrada deposit
their eggs in their cutaneous envelope.*

1 With the Gamasea, and Ixodea, the vulva is sit-
uated on the thorax ; while, with the Trombidina,
Bdella, Ilydrachnea, and Oribatea, it is upon the
belly ; see Treviranus, Verm. Schrift. Taf. V.

( Hydrachna and Trombidium) ; Audouin , Ann. d.
Sc. Nat. XXV. PI. XIV.; J. Muller , Nov. Act. Nat.
Cur. XV. Tab. LXVII. ; and Treviranus , Zeitsch.
f. Physiol. IV. Taf. XVI. fig. 2 (Ixodes). For the
ovaries and oviducts of the Acarina, we have only
the works of Treviranus, Verm. Schrift. I. p. 47 Taf.
VI. fig. 32 E. q. (Trombidium), and Zeitsch. f. Phys-
iol. IV. p. 190, Taf. XVI. fig. 7, 8, 10, \. \. (Ixodes).
I have observed with Ixodes ricinus the following
peculiarities, which were probably overlooked by
Treviranus with Ixodes americanus. The two
long ovaries anastomose arcuately at the posterior
extremity of the abdomen. The two oviducts, here
given off, open right and left into a pyriform uterus
whose neck communicates laterally with a large
caecum coming from the vulva. This caecum is
divided by a septum into a posterior, or larger, and
an anterior, or smaller, portion. The first receives
the sperm which flows from the second during cop-
ulation, and thence passes into the uterus and even
into the oviducts. The anterior portion represents
the vagina properly speaking, and is in communi-

* [ § 317, note 1.] See also Kaufmann (loc.
cit. in Siebold and Kdlliket’s Zeitsch. III. 1851,
p. 220), who has studied the development of the

cation with two short cylindrical glands filled with
transparent cells, and which secrete probably a
substance for enveloping the eggs. I have, more-
over, found with other Acarina (for example, with the
Ilydrachnea, Gamasea, and Oribatea) various or-
gans belonging to the genital apparatus, but without
perceiving their relations as clearly as with Ixodes.
However this may be, I am convinced that Dujar-
din (Ann. d. Sc. Nat. III. p. 20) goes too far in
saying that, with most Acarina, the eggs are devel-
oped loosely in the parenchyma of the body, with-
out the necessity of an ovary with proper walls.
According to this same naturalist (Ibid.), the Oriba-
tea are viviparous and have a large vulva which
can be closed by two lateral alae, and before which
is an orifice closed also by a similar apparatus.
This last orifice belongs to a tube which Dujardin
regards as a penis ; so that the Oribatea would be
hermaphrodites. As to the first point, — the vivipar-
ity of these animals, I have verified it for Hoplo-
phora, Zetes and Oribatcs ; but I cannot say as
much of the second point, for, as I have satisfied
myself, the posterior orifice is an anus, and the
anterior a vulva having an ovipositor.

~ For example, Hydrachna ; see Dugds Ann. d.
Sc. Nat. I. p. 165. A parasitic mite long known
under the name of Hydrachna concharum or Lim -
nochares anodbntae , and which lives in the cavity
of the mantle of Anodontae, buries its eggs deeply
in the skin of that organ; see Pfeiffer , Naturg.
deutsch. Land u. Siisswasser-Mollusk. Abth. II.
p. 27, Taf. I.; and Baer , Nov. Act. Nat. Cur. XIII.
p. 590, Tab. XXIX.

eggs from their first stages, in the ovary of Macro-
bins Dujardin. — Ed.

§ 318.

THE ARACHNOIDAE.

393

surround their eggs, grouped together, with a tough coaguhable substance,
and glue them to various bodies. It is, therefore, very probable that there
are special organs for the secretion of this substance. (3)

As yet, we have no observations on the internal genital organs of the
Pycnogonidae, although, for a long time, the females have been recognized
by their filiform odphores, composed of nine to ten articles, and situated in
front of the first pair of legs.®

With the Phalangidae, the two ovaries are blended together, and form a
flexuous tube occupying a large portion of the abdomen and continuous
anteriorly into two short oviducts. These last unite in a large oviduct
situated, loop-like, in the posterior extremity of the abdomen, between the
convolutions of the ovaries. Its anterior extremity receives a second ovi-
duct, which, after describing numerous convolutions, opens in a horny,
articulated ovipositor. This last can be protruded between the posterior
legs by means of a special muscular apparatus, on the under side of which
are two caeca opening into the oviduct at the base of the ovipositor.
These organs are either seminal receptacles, or the secretory organs of a
viscous substance.®

With most Ai'aneae, the two oblong ovaries are concealed between the
hepatic lobes, and open by the intervention of two short oviducts, into a
vagina situated between the two pulmonary sacs. This vagina is supported
by a horny plate, and opens externally through a transverse fissure, after
having previously received the excretory ducts of the two contiguous
Receptacula seminis. These last are pyriform and nearly always composed
of a deep-brown, horny substance ; they are attached to the cutaneous
envelope, and have, each, an equally horny excretory duct which is more
or less long and interlaced with the corresponding one on the other side.®
The females surround their eggs in groups, with a web, so that they have
no organs for secreting a viscid substance.

The Epeiridae offer a remarkable modification in their external genital
organs. The entrance to their vagina is covered by a horny process,
directed from before backwards, and at the base of which there are pyri-
form, pedunculated, seminal reservoirs. <7) It is yet undetermined whether
this process is connected with the act of copulation, or with the deposition
of the eggs.

The Scorpionidae have three ovaries consisting of as many longitudinal
tubes united by four pairs of transverse ones. The two external of the
former tubes are continuous anteriorly as oviducts, and unite in a short
vagina which opens at the base of thev abdomen. Before their junction,
the oviducts dilate into a round pouch, which, as it sometimes contains the
sperm, may be regarded as a Receptaculum seminis .®

o For example, Eylals , Limnochares , and Di-
plodontus.

4 See Johnston , Magaz. of Zool. I. p. 370 PI.
XIII. $ Milne Edwards , Hist. Nat. d. Crust. PI.
XLI. fig. 7 *, and Philippi , in fViegmann’s
Arch. 1843, I. p. 177, Taf. IX. With Phoxichi-
lidium , the two odphores are only five articled.

5 See Treviranus , Verm. Schrift. I. p. 34, Taf.
IV. fig. 20, 23 ; also Tulk , loc. cit. p. 318, PI. V.
tig. 26-29.

(i Treviranus (Bau d. Arachn. p. 37, Taf. IV.
fig. 32) has figured very correctly the ovaries and
their oviducts, lie has even seen the Receptacula
seminis , but he mistook them for cartilaginous
bodies (Ibid. p. 38, Taf. II. fig. 20, o. and Taf. IV.
fig. 40, o. 41). The anatomists who succeeded him

paid no attention to these organs. The seminal
receptacles are short and pyriform with Lycosa ,
Theridion , and Micryphantes ; but they have a
long excretory duct entwined with its opposite, with
Drassus , Salticus , and Thomisus.

T This process is S-shaped with Epeira diadema.
It has been described and figured by Leeuwen-
hoek, loc. cit. p. 336, fig. 8" *, Roesel, loc. cit. p.
253, Taf. XXXVII. fig. I, b. and Taf. XXXVIII.
fig. 1, 3 *, and by Degeer , loc. cit. p. 85, TaL
XII. fig. 10. See, also, Treviranus , Bau d.
Arachn. p. 39, Taf. II. fig. 18, and Savigny ,
Descript, de l’Egypte, loc. cit. PI. II. fig. 8 m. With
Ncphila fasciata, this process is tongue-shaped.

8 The female organs of the Scorpionidae have
been described by Meckel (Beitr. loc. cit. p. 113,

394

THE ARACHNOIDAE.

§ 319.

III. Male Arachnoldae.

§ 319.

From the few observations hitherto made upon the male organs of the
Acarina, it appears that they are formed after very different types. With
Trombidium , there are twenty red, testicular vesicles, attached by short
peduncles to the annular Vas deferens which opens between the posterior
legs. This last, before its termination, receives also two brown, long-
pedunculated vesicles, whose nature is yet unknown. (1>

With Ixodes , the testicles consist of a group of four to five pairs of
longer or shorter follicles, which unite in the middle of the abdomen, and
send off two small Vasa deferentia to the base of the chin-like process.
This last, together with the cheliceres, these animals introduce deep into
the vagina during copulation, while their two palpi, separated at a right
angle, are applied upon the thorax of the female.® With Gamasus, there
appear to be only two simple, isolated, testicular follicles,, each having a
deferent canal. With many Acarina, there is a short penis situated at a
point corresponding to that of the vulva of the females, and sometimes
concealed within the body.® With other Acarina, the males are distin-
guishable from the females, by the larger size of their cheliceres, and some
of the legs which serve to retain the females during copulation.®

With the Phalangidae, the testicles consist of numerous small caeca, all
united at one point into a long, flexuous deferent canal. This last is con-
tinuous into a Ductus ejaculatorius which traverses a muscular penis ; this
terminates with a hook-like gland, and its body is horny and surrounded by
a muscular sheath out of which it can be protruded under the thorax. ®
With many Opilionina, the posterior legs have remarkable spines and
excrescences which, undoubtedly, are used during copulation.®

With the Araneae, the testicles consist of two long, simple, interlaced
caeca, concealed between the hepatic lobes.® From them pass off two

Taf. VII. fig. 18-20) 5 Treviranus (Bau. d.
Arachn. p. 12, Taf. 1. fig. 12), and Muller (loc. cit.
p. 53 Taf. II. fig. 14-19). This last naturalist has
found, with the large African scorpions, eggs in the
lateral long, varicose and caecal appendages of the
ovaries. These appendages do not increase in size
except iD proportion as the eggs are developed ;
while, with the small European scorpion, the eggs
produce only simple pyriform folds on the ova-
rian tubes. I have found sperm and very active
spermatic particles in the seminal receptacles of
living females of Scorpio europaeus.

1 I have proved this complicated disposition of
the male organs with Trombidium holosericeum ,
where it had been wholly misapprehended by
Treviranus (Verm. Schrift. I. p. 48, Taf. VI. fig.
35).

^ This singular mode of coition had already been
observed by Dcgeer (loc. cit. p. 45, Taf. VI. fig.
6) with Ixodes ricinus, and subsequently by Ph.
IV. J. Muller ( Germar's Magaz. d. Entomol. II.
1817, p. 281) ; but it remained wholly unobserved
by the other entomologists. It appears that the
male of Ixodes ricinus , which differs considerably
from the female, has been mistaken for a different
species and named Ixodes reduvius ( Audouin ,
loc. cit. XXV. p. 422, PI. XIV. fig. 4), or Ixodes
rnarginalis ( Hahn , Die Arachn. II. p. 63, fig.
153). The characters peculiar to this sex are, a

dorsal shield covering the whole body, palpi shorter,
and teeth less numerous upon the also shorter chin
like process.

3 The penis is sub-ventral with Bdella, sub-tho-
racic with Gamasus , and behind the genital orifice
with Oribates. With Jrrenurus , it is inserted
on a tuberosity of the abdomen, giving the males a
very singular appearance ( [Dugis , loc. cit. I. p.
155, PI. X. fig. 20).

4 With the males of certain species of Gamasus ,
the two cheliceres are perforated, and the second
pair of legs is very stout and provided with spines
and excrescences. With Dermaleichus , it is the
third pair of these organs which is sometimes very
large and armed with robust nails. With Sarcop-
tes , the posterior legs are long and armed with
nails and discs, while with the females these same
legs are abortive.

■5 Treviranus , Verm. Schrift. I. p. 36, Taf. IV.
fig. 21, 22 •, and Tulle , loc. cit. p. 250, PI. IV. fig.
21-24.

G With Eusarcus , Gonyleptes , &c. The very
large cheliceres of the Phalangidae are not used in
the act itself of copulation, but are employed to
fight with on these jealous occasions ; s eeLatreille,
Hist. Nat. d. Fourmis, p. 380.

7 For the testicles of the Araneae, see Trevira-
nus , Bau d. Arachn. p. 37, Taf. IV. fig. 33, and
Brandt , Mediz. Zool. II. p. 89, Taf. XV. fig. 7.

§ 319.

THE ARACHNOID AE.

395

deferent canals to the base of the abdomen where, between the two pulmo-
nary sacs, there is a genital opening in a small horny plate. This opening
is only a simple transverse fissure which, in copulation, does not come in
contact with the vulva of the female. These animals always use their
hollow, spoon-shaped palpi, which often have a very complicated structure.
They are filled with sperm and applied to the entrance of the vulva. Fot
this purpose, the last article of the palpi, which is always hollow and much
enlarged, contains a soft spiral body terminated by a curved, gutter-like,
horny process. Beside this, there is an arched, horny filament, apd
several hooks and other appendages of the most varied forms. These
appendages are protractile, and serve, some to seize the female, and others
as conductors of the sperm.®

With the Scorpionidae, each of the two testicular tubes forms a loop
enveloped by the substance of the liver, and connected with its mate by two
transverse canals. The anterior border of each of these loops sends off a
short Vas deferens which opens at the base of the abdomen, receiving in
its track two caeca of unequal length. Of these, the longer contains a
granulo-vesicular substance, and is, perhaps, an accessory gland ; while the
shorter, from the character of its contents, is evidently a Vesicula serrti-
nalis. (9) A deeply crenated, small papilla projects out of the genital
orifice, and, as it is wanting with the females, may be regarded as a

8 For a long time, the excretory point of the Vasa
defer entia was undetermined, because the two
sexes of these animals had never been seen to place
in contact these genital orifices during copulation.
But when it was discovered that only the palpi of
the males touch the vulva, the excretory ducts of
the testicles were sought in these palpi. It is only
recently, however, that it has been perceived, that
with these animals, as with the Libellulidae (see my
memoir in Germans Zeitsch. f. d. Entomol. II. p.
423), the copulatory organ and the Vesicula semi-
nalis are entirely removed from the male genital
orifice. In order to be convinced that the applica-
tion of the male palpi against the female vulva
constitutes really the act of copulation, it is only
necessary to examine the palpi under the micro-
scope and compress them. From the last article a
large quantity of sperm will be seen to escape.
Then again, after copulation, the Receptacula sem-
inis of the females will be found filled with the
fluid. The form of the palpi with the males varies
almost infinitely according to the genera and spe-
cies. They are very simple and slightly swollen
with Clubiona and Lycosa, while, with Epeira ,
Tegenaria , Linyphia , Micryphantes , Salticus ,
Argyroneta , &e., their last article is so complicated
that the most minute description would be inade-
quate in giving an exact idea of it ; see the figures
of Lyonet , loc. cit. p. 383, PI. XIX. XX. $ Trevi-

ranus , Bau d. Arachn. p. 37, Taf. IY. fig. 35-
37 ; Brandt , Mediz. Zool. II. p. 87, Taf. XV. fig.
1 ; Savigny , Descript de l’Egypte, PI. I.-VIL;
Menge , loc. cit. p. 35, Taf. III. fig. 13-27.

Treviranus (Bau d. Arach. p. 33) has made an
exposition of the older opinions of Lister , Lyonet ,
Cleric , and Degeer , on the copulation of these ani-
mals 5 but he regarded the act as only a prelude
for exciting the sexual desires, and which would be
followed by a real copulation, consisting of the con-
tact of the male and female genital orifices. More-
over, Treviranus had never observed this last act.

The more recent observers, such as Dugts (Ann.
d. Sc. Nat. VI. p. 187), Menge (loc. cit. p. 36), and
Blackwall (Annals of Nat. Hist. XV. p. 225), have
naturally only confirmed the views of the older nat-
uralists. According to Menge. the males of Lin-
yphia and Agelena evacuate a drop of sperm from
their genital orifice, which is then received and
absorbed by the last article of their palpi.*

9 For the male organs of the Scorpions, which
have been very imperfectly described by Trevira-
nus (Bau d. Arachn. p. 22, Taf. I. fig. 11), see
Meckel (Beitrftg. loc. cit. p. 114, Taf. VII. fig. 14),
Serres (loc. cit. p. 89) and Muller (loc. cit. p. 59,
Taf. I. fig 8). I have seen distinctly with living
individuals of Scorpio europaeus , spermatic par-
ticles in motion in the small caeca which I have
called the seminal vesicles.

*[§319, note 8.] I have made a microscopic
examination of this curious palpus-structure in
connection with the general structural relations of
the internal genital organs, in some of the common
Araneae ( Tegenaria , Agelena , &c.) where this
formation is most marked. In Agelena , the pecu-
liar, corkscrew-like, horny process, situated in
the last, spoon-shaped article of the palpus, con-
tains a canal throughout, which commences in
a '•kind of receptaculum at the base of the pro-
cess. This receptacle is filled with the peculiar
granule-like bodies mentioned above (Note to §

316, note 7). As the most repeated and careful
examinations showed no spermatic particles in this
palpus-capsule, I was led to advance the view that
the palpi were only excitatory and not intromittent
organs, in the copulatory act (see Proceed. Boston
Soc. Nat. Ilist. IV. 1851, p. 106). But the question
is still open, and especially as some recent investi-
gators of the economy of these animals have observed
facts that would indicate the intromittent function
of these organs ; see particularly, Blackivall , Ann.
Nat. Ilist. passim, for several years past. — Ed.

396

§ 320.

THE ARACHNOIDAE.

rudimentary penis. It is yet undetermined if the two external, lateral,
pectiniform appendages situated near the genital orifice in both sexes,
serve any purpose during copulation. (10)

§ 320.

We have, as yet, only insufficient observations on the Development of the
Arachnoidae. However, those that we possess upon its first stages,™ show
that, with few exceptions,® here as with the Crustacea, the disappearance
of' the germinative vesicle is followed by a superficial and partial segment-
ation of the vitellus. There is thereby formed a thin embryonic layer, com-
posed of molecular corpuscles retained in a transparent viscid liquid, and
distinguished from the rest of the vitellus by its white color. While this
oval blastoderma, whose longitudinal axis corresponds to the ventral or
nervous side of the embryo, extends towards the sides and the back, it
divides into an external or serous, and an internal or mucous lamella,
the last of which gradually covers the remaining portion of the vitellus,
and becomes changed into the digestive tube and its appendages. In
the mean while, there appear, on the external surface of the serous lamella,
various symmetrical prominences and projections, which in time become
the segments of the body, the parts of the mouth, the tactile, and the
locomotive organs.

With the exception of the Scorpionidae, and Oribatea, which are vivi-
parous, the embryos of all the Arachnoidae are developed subsequent to the
deposition of the eggs.®

With the majority of Arachnoidae, the embryos, at their escape from the
egg, have the form of the adult.® The lower orders, only, form an
exception in this respect, for they acquire their definite form after several
moultings, and a true metamorphosis. With the Pycnogonidae, these

10 Tulk (Ann. of Nat. Hist. XV. p. 66) has
lately expressed the opinion that these combs serve
to clean the palpi, the tarsi, and the extremity of
the tail. He adduces, as proof, the presence of
transparent combs of exactly identical form, with
Obisium , between the pincers of the cheliceres, and
which are used for this purpose.

1 The first phases of development have not
been observed as yet except with the Araneae and
Scorpionidae ; see Herold, De Generat. Aranear.
in ovo, 1824 ; Rathkd, Zur. Morphol. Reisebemerk.
aus Taurien, 1837, p. 17, and in Burdach's
Physiol. H. 1837, p. 242 *, the same in Froriep's
neue Notiz. XXIV. 1842, p. 165 ( Lycosa sac-
cat a) ; also Kolliker, in Muller's, Arch. 1843, p.
139 ( Scorpio europaeus ) ; finally, Wittich , Observ.
quaed. de Aranear. ex ovo evolut., Halis. 1845, fig.
1, A. As to the development of the Acarina, I
have satisfied myself upon the eggs of the Oribatea,

* [ § 320, note 1.] See, also, Wilson , Researches
into the structure and develop, of a newly-discov-
ered parasitic Animalcule, &c., in the Philos. Trans.
1844, p. 305 ( Entozoon (Demodex) folliculorum ),
and Van Beneden , Recherches sur l’Atax upsilo-
phora, in the M£m. de l’Acad. Roy. de Bruxell.
XXIV. Wilson's details are imperfect, and throw
but little light on the real character of the develop-
ment of the follicle-parasite. It would appear,
however, to be truly one of the Arthropoda. — Ed.

t [ § 320, note 2.] For the embryology of the

that the same phenomena occur as with most of the
other Arachnoidae.*

2 I have distinctly seen, in the eggs of Macrobi-
otus Hufelandii , the segmentation involve the en-
tire vitelius. Kolliker (. Muller's Arch. 1843, p. 136)
has madej the same observation with Pycnogonum .f

3 The relations of the Scorpionidae in this respect
are very remarkable, for their embryos are devel-
oped in the ovaries at the spot even where the eggs
are formed 5 see Muller , loc. cit. p. 55, and Rathki ,
Zur Morphol. loc. cit. It is evident that the sperm
must ascend from the two seminal reservoirs into
the ovaries to fecundate the eggs. With the Ori-
batea, the embryos appear to be developed in a
kind of uterus situated immediately behind the
ovipositor.

4 With the Araneae, the sexual differences which
are so striking do not appear until after the first
moulting.

Tardigrada, see Kaufmann , loc. cit. in Siebold
and Kolliker' s Zeitsch. III. 1851, p. 220. The
type of development is like that of the Articulata in
general, and this would seem to clearly settle the
position of these animals in this class. Kauf-
mann confirms the observation of Siebold as to
the segmentation of the entire vitellus. After this
process has occurred, the mulberry like mass is
changed into the embryo, exactly as is obsenjed
with the eggs of the Arachnoidae in general. — Ed.

TIIE ARACHNOIDAE.

397

$ 320.

changes should be most prominent, for their embryos have a short unartic-
ulated body, and, beside the cheliceres, are provided with only four bi- or
tri-articulated feet. There is, however, a very long lash, attached, some-
times to the two cheliceres, sometimes to each of the four legs. It is not
until after successive moultings, that the other legs, the divisions of the body,
and the extremities, appear.®

With Emydium,5 (6) 7 8 and most of the Acarina, the embryos have only six
legs, when hatched ; but as they otherwise resemble the adults, their
metamorphosis consists only in the appearance of another pair of legs. A
true metamorphosis is observed only with Hydrachna. Here the embryos
have a very long and large snout which might easily be taken for a head
distinct from the trunk. <7) This disproportion between these two parts is
subsequently reversed, when the young pierce with their snout the bodies
of insects, while their own bodies, gorged with food, become of a monstrous
size. These young have six legs, and, during their parasitic life, were for a
long time described as distinct species under the generic name Achlysia,
until it was discovered that they possessed eight legs after their first moult-
ing.® Similar metamorphoses occur with the Trombidia which, as red,
hexapod larvae, are attached to flies, grasshoppers, plant-lice and various
other terrestrial insects. These, also, have been formed into proper genera
under the names of Astoma, Leptus, and Ocypeta.a) *

5 See Kroyer , Naturhist. Tids. III. 1840, p.
299, or Isis, 1841, p. 713, Taf. III. Tab. III. or
Ann. d. Sc. Nat. XVII. p. 288, PI. XIII. B.

6 See Doydre, loc. cit. p. 358. The embryos of
the other Tardigrada have four pairs of legs.

7 See Dugis, Ann. d. Sc. Nat. I. p. 166, PI. XI.
fig. 47. It follows clearly from the position of the
eyes, which are situated not upon this snout, but
upon the cephalothorax, that this snout is only a
support of the parts of the mouth, and not a head.

8 See Audouin , Mem.sur I’Achlysie in theMemde
la Soc. d’Hist.Nat. de Paris, I. p. 98, PI. V. No. 2). He

found these'red Achlysiae with monstrous bodies on
the dorsal surface of the abdomen of Dytiscus and
Hydrophilus. Others, smaller, were observed even
more frequently upon the segments of the body and
the articles of the extremities, withiVej7a, and Ra-
natra. The true nature of these epizoa has been
cleared up by Burmeister (Isis, 1834, p. 138, Taf.
I. fig. 1-6), and by Dugts (Ann. d. Sc. Nat. I.
1834, p. 166, PI. XI. fig. 49-55).

9 See Gervais , in Walckenaur , Apt^res, &c., III.
p. 178.

* [ § 320, end.] There is some ground for the
opinion that alternation of generation, so called,
occurs with some of the Arachnoidae. Dujardin
(Ann. d. Sc. Nat. 1849, XI. p. 243) has examined
the wall-mite found on the house and other flies —

84

the Acarus muscarum of Degeer , and the Hypo-
pus of Duges. It has neither mouth nor digestive
apparatus, but simply adheres to the animal on
which it lives, by a sucker. It may be the nurse
of a Gamas us ! — Ed.

BOOK FOURTEENTH.

INSECTA.

CLASSIFICATION.

§ 321.

As anatomists have been able to examine, with few exceptions, nearly
all the orders and families of the Insecta, their anatomical researches have not
been restricted, as in the preceding classes, to isolated genera or species,
but have embraced entire families. With such abundant materials, we
should go beyond the limits of our work in enumerating here all the genera,
or even all the families, whose organization has been studied.

A. Insects without Metamorphosis.

( Insecta ametabola.)

ORDER I. APTERA.

Families : Pediculidae, Nirmidae, Poduridae, Lepismidae.

B. Insects with incomplete Metamorphosis.

[Insecta hemimetabola.)

1. Moutii Suctorial.

ORDER II. HEMIPTERA.

Families : Coccidae, Aphididae, Psyllidae, Cicadidae, Cercopidae,
Naucoridae, Nepidae, Coreidae, Pentatomidae.

2. Moutii Mandibulate.

ORDER III. ORTHOPTERA.

Families : Physopoda, Forficulidae, Psocidae, Perlidae, Ephemeridae,
Libellulidae, Termitidae, Acrididae, Locustidae, Achetidae, Phas-
MIDAE, MaNTIDAE, BlATTIBAE.

$ 321.

THE INSECTA.

399

C. Insects with complete Metamorphosis.

( Insecta holometabola.)

1. Mouth Suctorial.

a. Two wings. Under lip changed into a suctorial organ.

ORDER IV. DIPTERA.

Families : Pulicidae, Nycteribidae, Hippoboscidae, Muscidae, Oestribae,
Syrpiiidae, Conopidae, Stomoxydae, Bombylidae, Antiiracidae, Lep-
tidae, Henopidae, Asilidae, Stratiomydae, Tabanidae, Tipuliuae,
CuLICIDAE.

b. Four scaly wings. Maxillae changed into a suctorial organ.

ORDER V. LEPIDOPTERA.

Families : Tineidae, Pyralidae, Geometridae, Noctuidae, Bombycidae,
Hepiolidae, Zygaenidae, Sphingidae, Papilionidae.

c. Four naked wings. Tongue changed into a suctorial organ.

ORDER VI. HYMENOPTERA.

Families : Apidae, Andrenidae, Vespidae, Formicidae, Scoliadae,
Mutillidae, Pompilidae, Crabonidae, Bembecidae, Chkysididae,
Cynipidae, Iciineumonidae, Siricidae, Tentiiredinidae.

2. Mouth Mandibulate.

a. Two posterior wings only.

ORDER VII. STREPSIPTERA.

b. Four membranous wings.

ORDER VIII. NEUROPTERA.

Families : Phryganidae, Sialidae, Hemerobidae, Myrmeleonidae,

Rhapiiidiadae, Panorpidae, Mantispidae.

c. Two upper wings corneous, and two under membranous.

ORDER IX. COLEOPTERA.

Families : Pselapiiidae, Coccinellidae, Chrysomelidae, Cerambycidae,

CuRCULIONIDAE, ClSTELIDAE, MeLOIDAE, TeNEBRIONIDAE, PyrOCUROIDAE,

Elateridae, Lamellicornes, Clavicornes, Hydrophilidae, Hydrocan-

TIIARI, STAPHYLINIDAE, CaRABIDAE.

\

400 THE INSECTA. § 321.

BIBLIOGRAPHY.

Reaumur. Memoires pour servir a l’histoire des Insectes. 1734.

Roesel. Insekten-Belustigungen. 1746.

Swammerdamm. Bibel der Natur. 1752.

Lyofiet. Traite anatomique de la chenille, que ronge le bois de saule,
1762, and Anatomie de differentes especes d’Insectes, in the Mem. du
Museum, &c., XVIII.-XX. 1829-32.

Degeer. Abhandlungen zur Geschiehte dcr Insekten. 1776.

Meckel. Beitrage zur vergleichenden Anatomie. 1808.

Gaede. Beitrage zu der Anatomie der Insekten. 1815.

Suckow. Anatomisch-physiologische Untersuchungen der Insekten und
Krustenthiere. 1818.

Straus- Diirckheim. Considerations generates sur 1’ Anatomie comparee
des animaux articules. 1828.

Kirby and Spence. Introduction to Entomology, 1816-28, or its trans-
lation into German by Oken, 1823-33.

Burmeister. Handbuch der Entomologie. 1832.

Brandt and Ratzeburg. Medizinische Zoologie. Bd. II. 1833.

Ratzeburg. Die Forstinsekten. 1837.

Lacordaire. Introduction a l’entomologie. 1834-38.

Westwood. An introduction to the modern classification of Insects.
1839.

Newport. Article Insecta, in the Cyclopaedia of Anatomy and Physi-
ology, II. 1839.

Leon Du four. Recherches anatomiques et physiologiques sur les
Hemipteres, 1833 ; and, Recherches anat. et physiol, sur les Orthopteres,
les Hymen opteres et les Neuropteres, 1841. Both of these are in the
Mem. a l’Acad. royale d. Sc. de l’Institut. de France, IY. VII.

Nicolet. Recherches pour servir a l’histoire des Podurelles, 1841, in
the Neue Denkschr. der allg. schweizer. Gesellschaft, &c. Bd. YI.

ADDITIONAL BIBLIOGRAPHY.

Dufour. Etudes anatomiques et physiologiques, sur une Mouche, in the
Mem. de l’Instit. IX. 1846, p. 545.

Recherches anatomiques et physiologiques sur les Dipteres, in

Ibid. XI. 1851, p. 171. See also his various communications on the
anatomy and metamorphosis of different Insecta, in the Ann. d. Sc. Nat.
VII. 1847, p. 5, and p. 14; VIII. 1847, p. 341 ; IX. 1848, p. 91, 199,
205, 344; XIV. 1850, p. 179; XVII. 1852, p. 65.

Blanchard.. De la Circulation dans les Insectes, in the Ann. d. Sc. Nat.
IX. 1848 ; p. 359 — also in extract in the Comp. rend. XXIV. 1847, p.
870, or in the Ann. Nat. Hist. XX. 1847, p. 112, or in Schleiden and
Froriep's Not. LXVI. 1847, p. 342.

Nouvelles observations sur la circulation du sang et la Nutrition

chez les Insectes, in the Ann. d. Sc. Nat. 1851, XV. p. 371.

Stein. Vergleichende Anatomie und Physiologie der Insekten. In
Monographieen, Erste Monographie : Die weiblichen Geschlectsorgane
der Kafer. Mib. 9 Kupertafeln. Berlin, 1847.

§§ 322, 323.

THE INSECTA.

401

Siebold. Ueber die Fortpflanzung von Psyche : Ein Beitrag zur Natur-
geschichte der Schmetterlinge — in Siebold and Killi Jeer's Zeitsch. I.
1848, p. 93; see, also, for further researches on the subject, his Bericht iib.
die entomol. Arbeiten d. schles. Gesellsch. in J. 1850, or its transl. in the
Transact, of the Ent. Soc. I. 1851, p. 234.

Leydig. Die Dotterfurchung nach ihrem Vorkommen in der Thierwelt
uud nach ihrer Bedeutung, in the Isis, 1848, Hft. 3.

Einige Bemerkungen iiber dei Entwickelung der Blattlause,

in Siebold and Killiker's Zeifsch. 1850, II. p. 62.

Anatomisches und Histologisches iiber die Larve von Corethra

plumicornis, in Ibid. III. 1852, p. 435.

Zur Anatomie von Coccus hesperidum, in Ibid. Y. 1853, p. 1.

Meyer. Ueber die Entwickelung des Fettkorpers, der*Tracheen und
der Keimbereitenden Geschlechtstheile bei den Lepidopteren, in Siebold
and Kclliker's Zeitsch. 1. 1849, p. 175 ; see also the Mitth. d. naturf. Ges.
in Zurich, Hft. 2, p. 206.

See, also, the various writings referred to in my notes. — Ed.

CHAPTER I .

EXTERNAL ENVELOPE AND CUTANEOUS SKELETON. v

§ 322.

The cutaneous envelope of the multi-articulate body of the Insecta con-
sists, as with the other Arthropoda, of a kind of external skeleton, of a con-
sistence sometimes leathery and soft, sometimes horny and solid. Its
elasticity and flexibility is limited to the points of junction of the segments
of the body, and of the articles of the extremities. Its characteristic
chemical substance is likewise chitine, a peculiar azotic matter insoluble in
caustic potass, and with which highly-colored pigments are often chemically
combined. (1) Chitine enters also into the composition of the hairs and the
scales of the skin, and the internal processes which may be regarded as an
Internal Skeleton.

§ 323.

Histologically, the cutaneous envelope is so variously and _ often so ex-

1 See Odier , Mem. de la Soc. d’Hist. Nat. de
Paris, 1. loo. cit. 5 Lassaigne , Compt. rend. XVI.
1843, p. 1087, or Froriep's neue Notiz. XXVII. p.
7, and Schmidt , Zur vergleich. Physiol. &c. p.
32. Lassaigne has proposed for this substance
the name Entonioderm. The coloration of the

* [ § 322, note 1.] Recent researches have
shown that the peculiar substance Chitine is not
limited in its distribution to the Arthropoda, for it
has been found in nearly every class of the Inver-
tebrata. See Grube , Muller's Arch. 1848, p. 461,

34*

cutaneous skeleton is probably due to an oil
with which the chitine is impregnated, especially
with the Coleoptera.

See Bern ard-Deschamps, Sur les Elytres dee
Coleopt^res, in the Ann. d. Sc. Nat. III. 1845, p.
354.*

and fViegmann's Arch. 1850, p. 253 *, Schultze ,
Beitr. zur Naturgesch. d. Turbellarien, p. 33 5 a ntf
Leuckart , Morphol. der wirbellosen Thiere, p. 49,
in Siebold and Kdlliker's Zeit§ch. 1851, p. 192,
and in flfyegmann's Arch. 1852, p. 22. — Ed.

402

THE INSECTA.

§ 323.

traordinarily complicated, that it is very difficult to recognize its elements.
When horny, there can always be distinguished an epidermis composed of
unnucleated, lamellated cells intimately blended together. These cells,
however, are often polyhedral, and so disposed as to form a simple layer ;
in other cases, they are more or less blended together, giving rise to undu-
lating or imbricated lines in the epidermis. In order to study the subjacent
layer, or dermis, the cutaneous envelope must be macerated and decolored
in caustic potass. This layer will then be found to be composed usually
of several lamellae superposed in various ways and thereby often producing
very elegant markings. In many instances, these reticulated or radiated
markings would indicate the presence here of intercellular passages, and
porous canals. a) In the thin, membranous portions of the skeleton, for
instance, the wings, the structure usually appears wholly homogeneous.

On the external surface of this envelope there are o en numerous ex-
crescences, such as tubercles, spines and hairs, which are usually hollow.
The hairs are sometimes simple and smooth, sometimes set with small hairs
or barbellate.® Many of these cutaneous formations are inserted by a
small peduncle in small fossae, to which they loosely adhere, and from
which they are very readily detached. Usually, they are flattened, scale-

1 Histological researches upon the cutaneous
skeleton have, as yet, been extended over only a
few species. I am able to cite only the works of
//. Meyer ( Muller's Arch. 1842, p. 12 ( Lucanus
cervus ), ’and of Plainer (Ibid. p. 38, Taf. III.
(Bom by x mori).

2 These barbellate hairs are found with the lar-
vae of all tJie Bombycidae (Rtfaumur, M£m. &c.
Tom. I. PI. VI., and Degeer, Abhandl. I. Taf.

ix.-xra.).

They are easily rubbed off, and when brought in
contact with our skin, they insinuate themselves
by the truncated extremity, and thereby often pro-
voke an insupportable itching or even an inflamma-
tion. The processionary moths are so much feared
in this respect as to pass for being poisonous ; see
Nicolai , Die Wander-oder Prozessionsraupe, 1833,
p. 21, and Ratzeburg , Du Forstinsekten, II. p.
127, Taf. I. fig. 11, 12, and Taf. VIII. The
pains which these hairs can produce with man, may
be judged by the disease which Ratzeburg suffered,
and of which he has given an account (Entom.
Zeit. 1846* p. 35).

The symptoms spoken of by this excellent ento-
mologist may be explained without attributing any
specific poisonous property to these hairs, if it be
considered that, like a fine powder, they rest on the
skin and may enter the respiratory organs by
inhalation, and penetrating the tissues encoun-
ter a multitude of nervous fibres. Their passage
into the tissues is the more easy, since they are
fusiform, very sharp at both extremities, the free

* [ § 323, note 2.] Will (Schleiden and Fro -
riep's Not. 1848, Aug. p. 145) has made chemico-
microscopical investigations upon the nature of this
peculiar poisoning power manifested in the proces-
sionary moths ) his researches were upon Bombyx
processionea. The poisonous material was found
to be formic acid in a free and highly-concentrated
state ; it was met with in all parts of the cater-
pillar, but especially in the faece3, in the greenish-
yellow liquid emitted by these animals when di-

one of which is provided with denticulations point-
ing upwards, while the opposite one is loosely in-
serted in a small fossa, so that they are detached
without breaking from their fastenings by the least
contact. The deep-colored spots observed on the
back of the processionary moths, and which are di-
vided into four parts by crucial lines ( Ratzeburg ,
Die Forstinsekt. loc. cit. Taf. VIII. a fig. l.L and

I. *), consist of callosities on which are situated
thousands of these small fossae from which arise an
infinite number of hairs. With many birds and
insectivorous reptiles, the hairs of the moths which
these animals have eaten, traverse the mucous
membrane of the stomach and enter the tissues.
I should not have thus mentioned this subject,
since for a long time the true nature of the hairy
stomachs of old cuckoos has been understood (see
the discussion on this subject between Brehm ,
Richter , Carus , Oken , and Bruch , in the Isis,
1823, p. 222, and 666, Taf. VIII., also, 1825, p.
579, Taf. IV.), if, recently the passage of hairs
from the digestive tube into the mesentery of frogs
had not given rise to a similar error. The mesentery
of these reptiles very often contains fragments of
hairs and the spines of insects, surrounded by con-
centric layers of connected tissue and thus arrested
in their course. These encysted hairs have been
described by Remak (Muller's Arch. 1841, p.
451) under the name of parasitic enigmatical horny
fibres, while Mayer at Bonn has gone so far as to
take them for Pacinian corpuscles (Die Pacinischen
Kdrperchen, 1844, p. 14, fig. 2).*

vided, and in the hairs. These hairs were mostly
hollow, and their cavity was not closed at their
base, but passed through the skin and appeared
connected with glands below. These observations
are the more interesting since this same observer has
shown that the poisonous material of the poison-
apparatus of the Hymenoptera, consists likewise
of formic acid. See my note under § 347, note

II. — Ed.

$$ 324, 325.

THE INSECTA.

403

like, and colored. Their forms vary infinitely not only according to the
species, but also according to the regions of the body. They are often ribbed
longitudinally, and denticulated or deeply serrated on their borders. These
scales are often inserted on the skin perpendicularly, thus forming a pelt-
like covering easily wiped off; sometimes they are imbricated and exactly
fitted to each other.®

§ 324.

The various parts of the cutaneous skeleton of the Insecta have been so
carefully studied in Zoology, that they may well be passed over here. As
the internal surface of this skeleton furnishes points of insertion to the vol-
untary muscles, the segments of the body on which these last are attached,
would naturally be developed in proportion to their volume. Thus with those
Insecta which have powerful masticatory organs, the head is remarkably large
on account of the prominent development of the masticatory muscles ; in
the same way likewise other fossorial, rapacious, or saltatory Insecta, indicate
their habits of life by the size of their legs, which are endowed with great
muscular power. It is for the same reason, also, that with the species
which fly, the mesothorax and metathorax are so largely developed ; for
these contain not only the muscles of the last two pairs of legs, but also
those of the wings. These relations are especially distinct in those families
or genera which embrace both winged and unwinged species.

On the internal surface of the cutaneous skeleton, are found, in the head
and thorax, processes which may be regarded as an internal skeleton
Some of these serve as septa, which separate certain organs, and others
furnish points of insertion to muscles, and then are often bifurcated. (I>

CHAPTER II.

MUSCULAR SYSTEM AND LOCOMOTIVE AND SONIFEROUS ORGANS.

§ 325.

The muscular fibres of the Insecta are striated, not only in the voluntary
muscles, but often also in those of organic life, as in the stomach and intes-
tine.0’ All are colorless or of a dirty yellow color. This last is especially
observed with the muscles of the thorax belonging to the wings, which differ,

3 This covering has a velvety aspect with the
Lepidoptera, Anthracidae, and Bombylidae ; it is
scaly on the bodies of many of the Curculionidae,
Melolonthidae, Clavicornes, Lepismidae, Poduridae
and on the wings of the Culicidae, and Lepidoptera.
It has always excited the attention of naturalists,
who have figured it in their works. See also
Uiaumur , and Degeer , loc. cit., also Lyonet ,
M£m. du Museum, XX. p. 82, PI. VI.-XI. ; Ber-
nard-Deschamps, Ann. d. Sc. Nat. III. 1835, PI.
LU. IV. j Ratzeburg , Die Forstinsekt. II. Taf. I.;

Du jar din , Observ. au microscop. p. 121, PI. VII.
IX. XI. XII. ; Nicole t, loc. cit. p. 22, PI. II.
(Poduridae), and H. Fischer , Isis, 1846, p. 401,
Taf. IV. (Coleoptera).

1 For the internal skeleton of the Insecta, see
Audouin , Ann. gener. d. Sc. physiq. VII. p. 182,
or Meckel's deutsch. Archiv VII. p. 435 ;
Eschscholtz , Isis, 1822, p. 52 *, Burmeister ,
Ilandb. &c. I. p. 251, and Newport, Cyclopaed.
loc. cit. II. p. 909.

1 Necrophorus.

404

THE INSECTA.

§ 326.

furthermore, from the others, in their transverse striae being less distinct, and
their fibrillae being more easily observed ; indeed, with most species, these
last show a tendency to separate even from the least pressure, while those
of the other voluntary muscles are very compactly united together.®

The muscles are attached directly upon the cutaneous skeleton, as with
the Crustacea. In the extremities, only, do there appear to be tendons ;
but these are merely very long, flattened processes of the skeleton, situated
in the axis of the articles of the extremities. They serve as points of
attachment to short muscular fasciculi which are there obliquely inserted,
after having arisen from the inner surface of the articles. With adult
insects, the segments of the body are only slightly movable, and have but
few muscles. But with the larvae, whose extremities are rudimentary, or
even wholly wanting, there is a very prominent muscular system situated
directly beneath the skin, and composed often of several layers of flattened
fasciculi.®

§ 326.

The Locomotive organs, properly speaking, of the Insecta, are the legs
and the wings. The true legs never exceed three pairs, and are inserted
upon the first three segments back of the head — Prothorax , Mesothorax,
Metathorax. Each leg is divided into a Coxa, a Trochanter, a Femur,
a Tibia, and a Tarsus. The tarsus is divided into several articles, the
number of which reaches even five. The form of these legs varies infinitely
according to the mode of life of each species. The most common are those

to which are usually given the names :

2 This is so with the Diptera, Hemiptera, and
Hymenoptera, with the muscles of whose wings the
elements may be very easily separated.*

3 Lyonet (Traite, &c., p. 114, PI. VI.-VIII.) has
given a very detailed account of the muscles of the
larva of Cossus. See also Newport , Philos.
Transact. 1836, p. 537, PI. XXVII. (the cutaneous
muscles of the larva of Sphinx ligustri ), and

* [ § 325, note 2.] The delicate and beautiful
structure of the thoracic muscles of some of the In-
secta, has been carefully studied of late, and has
aided not a little in the elucidation of the histology
of the muscular tissue. See Lehert , Recherches
sur la formation des muscles, &c., in the Ann. d Sc.
Nat. XIII. 4850, p. 182-195, PI. VII. fig. 18-27 5
but especially Aubert , Ueber die eigenthiimliche
structur der Thoraxmuskeln der Insekten, in Sie-
hold and Kolliker's Zeitsch. IV. 1853, p. 388.

This last-mentioned naturalist states that he has
observed a new form of muscle-element in the
thorax of the Libellulidae, consisting of primitive
muscular bands by means of which, with a beaker-
shaped apparatus, the wings are moved. These
fibres consist of flattened riband-like bands, striated
on their borders as well as on their flat surface.

I have recently studied the elements of the
thoracic muscles of many Diptera ( Culex , espec-

Pedes cursor ii, aralulatorii, gressorii ,

Straus , Consid. &c. p. 140, PI. III. IV. {Melolon-
tha vulgaris).

Reference may be also made to the works of
Meckel (System, &c., III. p. 22), Cuvier (Lemons,
&c. II. p. 64), Burmeister (Ilandb. &c. I. p. 267),
Lacordaire (Introduct. d l’Entomol. II. p. 249),
and of Newport (Cyclopaed. &c. loc. cit. p. 934).

ially) with the highest and best microscopic powers.
The discs composing the primitive fibrillae, easily
separate and may be studied by themselves. But,
with the best powers, I have been unable to observe
in them anything but that each disc is a solid,
homogeneous light-refracting body. The fibrilla
appears to be formed by the aggregation of these
discs in a linear series and with regular inter-
spaces 5 no sheath, by which these discs would be
retained in a row, was observed. Contraction of
the fibrilla takes place by an approximation of the
discs to each other, and the consequent greater or
less disappearance of the interspaces. These phe-
nomena can be easily observed, and, it may be
added, there are often seen isolated fibrillae con-
tracting and relaxing, thus showing that the real
phenomenon of muscular contraction, does not de-
pend upon the nervous system, however much the
action of this last may serve as a stimulant. — Ed.

§ 326.

THE INSECTA.

405

natatorii , saltatorii, rapt or ii, and fossorii.m The tarsal articles are often
enlarged, in which case they form, on their under surface, either a naked,
fleshy sole, or a thiekly-pilose ball of the foot, which is usually cordiform.
With the Dytiscidae, several of these tarsal joints are changed into a disc
provided with suckers. The last article of these organs bears usually two
movable hooks, which are sometimes deeply bifid or denticulate on their con-
cave border.® It is rare that there is a third hook between them.® But with
the Strepsiptera, and Physopoda, all the hooks are wanting. The Diptera
and many Hymenoptera, have, moreover, under these hooks, soft lobules
(Arolia) provided with numerous small papillae, by means of which these
insects can fix themselves to objects.® With a great number of larvae, the
six legs are very short or abortive, or even completely wanting. In the
first case, they consist, usually, of merely a hook, but these larvae have also
many short obtuse processes on the other segments of the body, and by
means of the hairy soles on the extremity of these, they can fix themselves
on bodies and thereby move along.® With many entirely apodal larvae,
these processes are replaced by simple tubercles, or by belts of backwardly-
pointing bristles or spines, which serve as points of support in their loco-
motion.®

The organs of flying are the anterior and the posterior Wings. The first
are inserted on the mesothorax, and the second on the metathorax ; but in
nearly all the orders, there are genera with which these organs are wholly
wanting. <7) In other genera, the females alone are wingless,® which is
also true of the neuters of certain families.® It is more common still, to
seethe posterior wings changed into balancers ;<10) and this same transforma-
tion occurs also, but very rarely, with the elytra. <U) The wings, properly
speaking, are only prolongations of the cutaneous skeleton traversed by
tracheae and blood-canals. Their forms, their nervures, their folds, &c., as
well as their sometimes complete abortive condition, may here be passed
over, for all these points belong to the domain of Zoology.^

1 For the marching, leaping, and swimming of
insects, see Straus , Consider. &c. p. 180.

2 Thus, the hooks are bifid with Melon, and den-
ticulate with the Pompilidae, Ilippoboscidae, Cis-
telidae, and with Taphria , Dolichus , C ala thus,
and Pristonychus , of the Carabidae.

3 This third hook is found, for example, with
Lucanus cervus. With larvae of the Meloidae,
the legs are terminated by three very remarkable,
straight, lanceolate hooks, known by the name of
Triunguiinus. Many of the Curculionidae can
grapple objects by means of the immovable hooks on
their tibiae.

4 The Tenthredinidae have a lobule of this kind
on each of their legs, and the Diptera have even
two to three. For these lobules, as well as for the
tarsi of Insecta in general, see the beautif’i figures
given by Everard Home (Lectur. on C " .1”. Anat.
IV. PI. LXXXI.-LXXXIV.). According to Black-
mail (Trans, of the Linn. Soc. XVI. p. 487, 767 *,
and Ann. of Nat. Hist. XV. p. 115), the papillae of
the Arolia secrete a viscid substance which en-
ables the Insecta having these organs to walk on

* [ § 326.] Leidy (Proceed. Acad. Sc. Philad.
III. 1846, p. 104) has described a peculiar mechan-
ism by which the membranous wings of Locusta
are closed in a plicated manner like a fan. This
mechanism consists of spiral ligamentous bands,
wound, like the thread of a screw, around the
transverse or connecting veins, which latter are
also flexible. By this arrangement, upon the con-

steep and smooth surfaces. But this assertion re-
quires further proof, although it is admitted by
Spence (Trans, of the Entomol. Soc. IV. p. 18).

5 With the Lepidoptera, and Tenthredinidae.

6 With many Diptera.

7 Among the Orthoptera, the wings are wanting
with some Blattidae, Acrididae, Phasmidae, and
Psocidae *, among the Hemiptera, with Acanthias,
and Rhizobius ; and among the Diptera, with
Melophagus , Phtjyridium, and Pulex Jlagel-
los.

8 With Lampyris , some Blattidae, Coccidac,
Bombycidae, Geometridae, also with the Mutillidae
and the Strepsiptera.

6 With the Forraicidae and the Termitidae.

lb With the Coccidae and the Diptera. The pos-
terior wings are entirely wanting with some Ephem-
eridae.

11 The two singularly distorted balancers of the
Strepsiptera, situated in front of the wings and in
rapid and unceasing motion, are, from then1 inser-
tion, only abortive elytra.

traction of the alary extensors, the spring-like liga-
ments, or ligamenta spiralia, are stretched in the
expansion of the wings, and upon the relaxation or
cessation of the action of the muscles, the physical
properties alone of the ligamenta spiralia, in re-
suming their unstretched state, close the wings. —
Ed.

406

THE INSECTA.

§ 327.

The movements of the wings are produced by two extensor and several
smaller flexor muscles, which arise from the middle and posterior thoracic
segments, and are inserted on a tendinous process at the base of each wing.
The size of these muscles is proportionate to the size of the wings and their
mode of use in flight. They are, consequently, all equally developed when
the four wings participate equally in the act of flying, as is the case with
the Lepidoptera, Hymenoptera, the majority of the Neuroptera, the Libel-
ludidae, Perlidae, and finally, the Cicadidae, and the Aphididae.

The muscles of the anterior wings are comparatively smaller than those
of the posterior, when the first are not used, properly speaking, except to
cover the latter, as is the case with the Coleoptera, the Bugs, and many of
the Orthoptera.(12)

With most of the Poduridae, and with the young larvae of Xenos sphe-
cidarum, there is a peculiar, fork-shaped, saltatory organ. It is inserted
on the posterior extremity of the body or under the abdomen, and, when
at rest, points horizontally backwards. By means of a special muscular
apparatus, this fork is bent forwards and applied against the abdomen; it is
then returned violently into its original position, thereby tossing the animal
a considerable distance. (13)

§ 327.

Many of the Insecta produce sounds which we perceive partly as clear
tones, and partly as confused noises. These are due, sometimes to partic-
ular soniferous organs, but more often to vibrations of the cutanous skel-
eton produced by special muscular organs, or to the rubbing of certain
parts against each other. But in every case, without exception, the sound
is due to the action of voluntary muscles, and has no connection with the
respiratory organs.™

The buzzing produced by many Diptera, and Hymenoptera, during flight, is
due, without doubt, to vibrations of the thorax produced by the rapid and
successive contractions of the muscles of the wings in this act.® Further
researches are necessary to show if the sounds produced by certain butter-
flies are due to rubbings of some parts of the cutaneous skeleton, or to a
special soniferous apparatus.® But the sharp sounds of many Coleoptera

12 For the flight of Insecta, see Straus , Con-
sider. &c. p. 200 ; but especially the extensive
work, illustrated with many figures, of Chabmer ,

du Museum, VI.-VIII.

13 See Nico/et , loc. cit. p. 39, FI. III. *, and my
BeitrUg. zur Naturg. d. wirbell. Thiere. p. 84, Taf.
III. fig. 70. This fork is wanting in the genera
Ackorutee and Anurophorus , as well as with
th»* larvae of Stylops among the Strepsiptera.

1 Some Insecta produce sounds by striking or
rubbing certain parts of their cutaneous skeleton
against the body. The males of Mycterus curcu-
lioides knock with such violence the extremity of
their body against the boughs on which they have
alighted, that they produce a pretty loud sound,
designed, probably, to call the females.

The larvae of Vespa crabro , when hungry,
scratch the walls of their cells with the point of their
jaws, and thus call the attention of the parents to
their condition.

2 The buzzing of these Insecta has been at-
tempted to be explained in various ways. At
all events, it cannot be due alone to the movements

of the wings, for it persists sometimes after the re-
moval of these last. Neither can it be attributed
to the rapid passage of air through the stigmata of
the thorax, causing vibrations in that part of the
body. Burmeister , who has advocated this last
opinion (Handb. &c. I. p. 508, and in Poggen-
dorps Ann. d. Physik. XXXVIII. 1836, p. 283,
Taf. III. fig. 7-9), compares these sounds to those
produced by a siren j but this theory has been
fully refuted by Goureau , Solier , and Erickson
(see Silbermann^s Revue Entomol. III. p. 105,
and Ann. de la Soc. Entom. de France, VI. 1837,
p. 31, and Wiegmann' s Arch. 1838, II. p. 193).
The various sounds of flies and bees may be imi-
tated, moreover, by placing a vibrating tuning-
fork in contact with a band of stretched paper, —
an experiment in which the vibrations of the air
take no part.

3 It is said that, with Euprepia pudica , the pe-
culiar sounds are produced by the rubbing of a
callosity of the two posterior hips against the mid-
dle hips ( Solier , Ann. de la Soc. entom. loc. cit.).
The cry of Acherontia atropos has been attempted

§ 327.

THE INSECTA.

$

407

are caused by the rubbing of their prothorax against the peduncle of the
mesothorax, or by grating the ridges of the abdomen against the internal
surface of the elytra. Reduvius stridulus, Mutilla europaea, and Mantis
religiosa, produce also certain sounds by the friction of particular portions
of their skeleton. i4> The males of many Acrididae produce their creaking
sounds by playing, as with the bow of a violin, upon the lateral borders of
their Elytra, by their posterior thighs which have a longitudinal granular
ridge on their internal surface.® The peculiar cry of the male Locustidae
and Achetidae is produced by the base of their elytra. The very hard
and sharp internal border of one of these elytra rubs against a horny ridge
upon the under surface of the other, close to the tympanitic disc.®

With the males of the musical Cicadidae, there is a very remarkable sonif-
erous apparatus, situated on the under surface of the first abdominal
segment. It consists of two spacious drums at the base of which is a dry,
plicated membrane, to which is attached a large muscle of conical form,
arising from a median, bifurcated process of the second abdominal segment.
The entrance of each of these drums is more or less covered by a round-
ing operculum which is free behind. The muscle draws the membrane
inwards, then relaxing, this last returns by its own elasticity, producing, as
from the bending up and down of a metallic plate, a loud, clanging sound.
This sound is undoubtedly considerably increased by the resonance of the
air in the drums and in the neighboring vesicular tracheae.®

to be explained in various ways, but none of the
causes yet assigned are satisfactory ; see Passer ini,
Ann. d. Sc. Nat. XIII. 1828, p. 332 ; R. Wagner,
in Muller's Arch. 1836, p. 60 ; Goureau , Nord-
mann, and Duponchel , Ann. de la Soc. entom. VI.
-IX., or Wiegmann's Archiv. 1839-41.*

4 See Burmeister , Handb. &c. I. p. 507, and
Goureau, in Silberman's ltevue Entom. III. p.
101.

o See my observations in Wiegmann's Arch.
1844, I. p. 53. This fiddling movement may be
easily observed with the males of Gornphoceros
and Oedipoda. Pneumora maculata has, upon
Hie sides of the second abdominal segment, a very
strongly denticulate, oblique ridge, against which
is rubbed, probably, a horny process situated on
the internal surface of the posterior thighs. 1 am
yet unable to account for the way in which the
males of Oedipoda stridula produce their hoarse
buzzing, during flight.

* [ §327, note 3.] Haldeman {Sil liman's Jour.
May, 1848) states that Litliosia miniata, Kirby,
or an allied species, produces an audible stridula-
tion by vibrating the pleura beneath the wings,
this part being marked in recent specimens by par-
allel lines, apparently indicating the position of the
muscles. According to him, it is possible that the

6 For this soniferous apparatus, see Goureau
and Solier, Ann. d. la Soc. Entom. 1837, p. 31 ;
Newport, Cyclopaed. loc. cit. II. p. 928, fig. 394-
396 ; Goldfuss, Symb. ad. Orthopt. quorund.
oeconomiam, Bonn. Diss. 1843, p. 5, fig. 1-10 *, and
my observations in Wiegmann's Arch. loo. cit. p.
69. Burmeister (Handb. &c. I. p. 511) has
sought to explain this sound by referring it to the
powerful escape of the air from the stigmata of the
Locustidae and Acrididae ; but this is unsatisfac-
tory.

1 For the soniferous apparatus of the musical
Cicadidae, see Reaumur, Mem. Y. 4th m£m. PI.
XVII. ; Burmeister , Handb. &c. I. p. 513 •,
Ratzeburg, Mediz. Zool: II. p. 208, Taf. XXVII.
and especially Carus , Analekt. zur Naturwiss. p.
142, fig. l-18.f

European Acker ontia atropos may produce its
peculiar sound in a similar manner. — Ed.

t f § 327, note 7.] See also my investigations
upon, this apparatus of the Cicada septendecim in
the Proceed. Boston Soc. Nat. Hist. 1851, p. 72. —
Ed.

40S

THE INSECTA.

§ 328.

CHAPTER III.

NERVOUS SYSTEM.

§ 328.

The central parts of the nervous system consist, with the Insecta, as with
the other Arthropoda, of a Brain and a Ventral Cord.(1>

The brain is situated in the cephalic segment, and is composed of a
Ganglion supraozsophageum, connecting with a Ganglion infraassophageum
which is smaller, by two lateral commissures which embrace the oesophagus.
The first of these ganglia corresponds to the cerebrum of the Vertebrata;
and the second is comparable perhaps to the cerebellum or spinal cord.

The ventral cord succeeds upon the sub-oesophageal ganglion, and con-
sists, sometimes of a single ganglionic mass, sometimes of a chain of ganglia
more or less approximated and connected by double, longitudinal commis-
sures.® The number of the ventral ganglia, which is never greater than
that of the segments of the body, as well as the presence and length of the
longitudinal commissures, depend often upon the number, the size, and the
mobility of the segments of the body to which they belong. With those
Insecta whose segments are very short and rigid, the ganglia are closely
approximated or even entirely blended together ; while, in most larvae,
where the segments of the body are equally developed and flexible, the
ganglia are separate, nearly equal in size, and connected by pretty long
commissures. These last are rarely united into a single cord, although the
ganglia, not only those of the ventral cord, but also those of the brain,
appear, nearly always, to be composed each of two united ganglia.

Aside from the differences presented according as the insect may be a
larvae, a pupa, or an imago, the nervous system varies so much even in
the same group, that it may be quite dissimilar in species which, in other
respects, are very closely allied. These modifications refer to the number
of the ganglia, the length of their commissures, and the more or less com-
plete fusion between certain ganglia.

The superior cerebral ganglion, which is often composed of two hemi-
spheres more or less fused together, gives off the two antennal and the two
optic nerves. The simple eyes or stemmata, either when alone, or when
coexistent with compound or faceted eyes, always receive their nerves from
the same ganglion ; although these last are sometimes given off from a trunk
in common with the optic nerve. The sub-oesophageal ganglion furnishes
nerves chiefly to the mandibles, to the maxillae and their palpi. With the
perfect Insecta, the three thoracic are much more voluminous than the ab-
dominal ganglia. They send nerves not only to the legs, but also to the
muscles of the wings.

I For the nervous system of the Insecta in gen-
eral, see Burmeister , Handb. &c. I. p. 290 5
Lacordaire , Introd. &c. II. p. 183 ; Newport ,
Cyclopaed. II. p. 942, and Blanchard , Ann. d. Sc.
Nat. V. 1846, p. 273. L. Dufour (M6m. pr£s. 5.
I’ Acad. d. Sc. IX. 1846, p. 562, PI. I. fig. 16) has
given a very exact description of this system in
Sarcophaga haemorrhoidalis.

2 Entomotomists are not agreed as to the number
of the abdominal ganglia, for the sub-cesophageal
ganglion is sometimes regarded as the first of the
ventral cord. For the nervous system of the larva
and pupa of Sarcophaga , see L. Dufour , loc. cit.
PI. I. fig. 12-15.

§ 329, 330.

THE INSECTA.

409

The ventral ganglia are usually small, coequal, and give off no nerves
except to the segments of the abdomen. The last ventral ganglion, alone,
is larger, for it furnishes, in addition, nervous filaments to the rectum, and
to the excretory ducts of the genital organs.

Usually, the nerves arise in the ganglia by two or three principal roots.
Some nerves, however, arise from the interganglionic cord. In those
species where the ventral ganglia are entirely fused together, the nerves
arise close together, but immediately diverge in different directions.

§ 329.

As to the Intimate Structure of the nervous system of the Insecta,
both the nerves and the ganglia are always surrounded by a fibrous neu-
rolemma, and, according to carefully -made researches, are never wanting in
the two usual anatomical components. Between the extremely tenuous
primitive fibres, are interposed, in the ganglia, very small globules. These
last, nucleolated, usually contain also a finely-granular substance, colorless,
though sometimes reddish or brownish.®

There are, with the Insecta, as with the Crustacea, two modes of the dis-
position of the fibres in the ganglia. The first, which form nervous, infe-
rior cords, are disseminated in the ganglia ; while the others, which belong
to the superior nerves, simply pass through or over these ganglia. These
two kinds of fibres give off, laterally, nervous filaments, which, uniting,
form peripheric nerves of a mixed character. The superior cords corre-
spond, probably, to the motor nerves, and the inferior to the sensitive nerves
off the Vertebrata.®

§ 330.

The Disposition of the nervous system in the various orders of Insecta
presents the following differences :(1) 2

Among the Aptera, the ventral cord of the Pediculidae is composed of
three contiguous ganglia situated in the thorax. The prothoracic gan-
glion connects with the brain, and the metathoracic sends nerves to the ab-
domen.® The nervous system of the Poduridae differs from this, in their
three thoracic ganglia being separated, and their interganglionic longitudi-
nal commissures being wide apart.® More widely different still, is the
ventral cord of the Lepismidae ; it is composed of eleven ganglia connected
by double longitudinal commissures.®

With the Hemiptera, this system is limited to two thoracic ganglia, of
which the anterior is the smaller. With Pentatoma, and Cicada, these
two ganglia are not separated except by a constriction ; while, with Nepa,

1 It was undoubtedly from their extreme deli-
cateness that these ganglionic globules were over-
looked by Treviranus (Beitriig. zur Aufkl&r. d.
Erscheinung. u. Gesetze d. organisch. Lebens. I.
lift. 2, p. 62). They have been distinctly seen by
Ehrenberg (Unerk. Struct. &c. p. 56, Taf. VI. fig.
6 (Geotrupes)), Pappenhcim (Die specielle Gewebe-
lchre d. Gehororg. p. 51), Helmholtz (De fabric.
Syst. nat. &c. p. 21), Hannover (Recherch.
microscop. &c. p. 71, PI. VI. fig. 81, 82 ( Aeschna ))
and Will {Muller's Arch. 1844, p. 81).

2 This difference of the nervous cords was first
pointed out by Newport with the pupa and imago
of Sphinx ligustri (Philos. Trans. 1834, part II.

35

p. 389, PI. xm.-xvn. and Cyclopacd. loc. cit. p.
946). Hagen (Entom. Zeit. 1844, p. 364) has since
observed it with Aeschna grandis and Gryllo -
talpa vulgaris.

1 Various and special accounts of the general
disposition of the nervous system of insects may
be found in Cuvier , Lemons, kc., III. 1845, p. 334.

2 S wammerdamrn , Bib. der Natur. p. 36, Taf.
II. fig. 7.

3 Nicolet , loc. cit. p. 44, PI. IV. fig. 1 {Smyn-
thurus).

4 Treviranus , Verm. Schrift. II. lift. 1, p. 17,
Taf. IV. fig. 3.

410

THE INSECTA.

§ 330.

they are connected by two long commissures. From the posterior of these
ganglia pass off, in a ventral cord, two main trunks, approximated, which
send off, in their course, lateral branches towards the periphery; with
Pentatoma , these two main trunks are fused into one.®

With the Diptera, the ganglionic chain is always connected by simple
commissures. The number of ganglia varies with the families, and, usually,
is proportionate to the length of the segments of the body.® The ven-"
tral cord is most concentrated with the Hippoboscidae/7' the Oestridae,
and the Muscidae calypterae ; it consists of only a single thoracic gan-
glion, from which pass off nerves in various directions. The Muscidae
acalypterae, on the contrary, the Syrphidae® and the Conopidae, have,
beside this thoracic gauglion, one or two ventral ganglia ; while the Sceno-
pinidae have five, and the Tabanidae, Stratiomydae,® Therevidae, Leptidae,
Asilidae, and Boinbylidae, have six. Their number is still larger with the
Empidae, Culicidae, and Tipulidae ; — there being, in the first, three tho-
racic and five abdominal ganglia; and in the last two, three thoracic and six
abdominal ganglia. The larvae of the Diptera usually have one more pair of
ganglia than the adults. It is only in those species whose ventral cord is
fused into a single mass, that the same concentration is observed with the
larvae. °U) The larvae of the Diptera have either a moniliform ventral
cord, composed of ten approximated ganglia, or a chain of eleven of these
masses, connected by long commisstires, which are often double. (11>

With the Strepsiptera, alike in the three states of larva, pupa and
imago, the ventral cord consists only of a large thoracic ganglion, from
which pass off nerves in various directions.02'

With the adult Lepidoptera, the ventral cord consists of seven ganglia,
of which the first two are the largest and belong to the thorax. The con-
necting commissures are not double except between the thoracic ganglia ;
those of the others being more or less fused into a single cord. In the
Caterpillars, the ventral cord consists of eleven nearly equal ganglia ; the
two commissures between the first three of these, are quite wide apart ;

5 Treviranus , Beitr. zur Anat. u. Physiol, d.
Sirmeswerk. lift. 1, Taf. II. fig-. 24 (Cicada), and
L. Du, four , Recherch. sur les Hemipt^res, p. 259,
PI. XIX. fig. 801-S03 (Pentatoma, Nepa and
Cicada).*

G For the nervous system of the Diptera, see
L. Dufour, Ann. d. Sc. Nat. 1844, p. 245.

7 L. Dufour, Ibid. III. 1845, p. 64, PI. H.
fig. 12.

8 Bu/ /neister, Handb. d. Entomol. I. 307, Taf.
XVI. fig. 11 (Eristalis tenax).

9 S wammerdamm, Bib. d.Nat. p. 270, Taf. XLI.
fig. 7 (Stratiomys).

10 I have found the ventral cord of the larva of
Oestrus bovis concentrated into a single large
ganglion, situated at the extremity of the thorax.
I think, therefore, that the description of the nervous
system of the larva of Oestrus ovis given by J.
L. Fischer (Observ. de Oestro ovino ^tque bovino.
Diss. Lips. 1787, p. 32, or in Werneri, Vermium

* [ § 330, note 5 ] For the nervous system of
Belostoma, with all its details, see Leidy, History
and Anatomy of the hemipterous Genus Belostoma,
in the Jour. Acad. Nat. Sc. Philad. I. 1847, p. 65,
PI. X. fig. 13. — Ed.

t [ § 330, note 11.] In the larva of Corethra

intestin. exposit. contin. tertia. p. 2S, Taf. III. fig.
4), and according to which, two long ganglionic
cords, connected by transversal anastomoses, ex-
tend the whole length of the body, — is based on inex-
act observations. In the larvae of Piophila and Eris-
talis, several ventral ganglia fused together form a
single abdominal cord ; see Swammerdamm, Bib.
der Nat. p. 279, Taf. XLI II. fig. 7, and Burmeis-
ter, Handb. loc. cit. Taf. XVI. fig. 10.

11 The larvae of Stratiomys have an abdominal
cord composed of ten contiguous ganglia (Swam-
merdamm, Bib. der Nat. p. 264, Taf. XL. fig. 5).
With those of Culex, Chironomus, Simulia , and
other Tipulidae, the ten ganglia are wide apart,
and connected by double longitudinal commis-
sures.!

12 In the apodal larvae and the larvae-like fe-
males of Xenos Rossii , I have found this nervous
mass in the first segment of the body which corre-
sponds to the cephalothorax.

plumicomis, Ley dig found the ventral cord com-
posed of eleven, instead of ten ganglia ; see Anato-
misches und Histologisches ub. d. Larve von Core-
thra plumicornis, in Siebold and Kolliker's
Zeitsch. III. 1852, p. 438. — Ed.

§ 330.

THE INSECTA.

411

while those of the others are usually fused together. a3) During the pupa-
state, a remarkable change takes place. The commissures between the
first and second, and the third and fourth ganglia, are gradually shortened.
The ganglia are thereby gradually approximated, and, in the end, are fused
together, forming the two thoracic ganglia of the adult, which send off
nerves to the legs, and to the muscles of the wings. At the same time, the
fifth and sixth ganglia entirely disappear or are fused into one.(,4)

With the Ilymenoptera, the ventral cord is composed of seven to eight
ganglia connected by double commissures. The first of these, smaller
than the second, is, like it, produced by the fusion of several ganglia ; and
both are situated in the thorax. Of the remaining five or six abdominal
ganglia, the last two are closely approximated, or fused into one.(I5) Here,
as with the Lepidoptera, the number of ganglia in the ventral cord of the
larvae, is eleven, as has been specially shown in the false caterpillars of the
Tenthredinidae.(16)

With the Orthoptera, and Neuroptera, the nervous system is nearly
always composed, in their various states, of three thoracic and six to seven
abdominal ganglia connected by double commissures and forming a chain
as long as the body.<17)

With the Coleoptera, the number and disposition of the ventral ganglia
present the widest variations of all. The longitudinal commissures, always
double, are shortened or even wholly wanting at certain points. The
ganglionic chain is, therefore, more or less abbreviated, and sometimes the
ganglia are almost fused into a single mass. In this respect this system
here presents two principal types, the limits between which, however, have

13 For the nervous system of the larvae of Va-
nessa urticae and Bombyx mori , see the figures of
Swammerdamm, \oc. cit. p. 387, 230, Taf. XXVIII.
fig. 3, and Taf. XXXIV. fig. 7 ; also for that of the
larva and imago of Cossus ligniperda , the works of
Lyonet , Traite, &c., p. 190, PI. IX., and in the
Mem. du Mus. loc. cit. p. 191, PI. LI. (17). For
that of Gastropacha pint, pupa and imago,
see Suckow , Anat. physiol. Untersuch. p. 40,
Taf. VII. fig. 37, 38 •, but see especially the excel-
lent description of that of the larva, pupa, and
imago of Sphinx ligustri , for which we must
thank Newport. Philos. Trans. 1832, p. 383, PI.
XII. XIII. 5 also, 1834, p. 389, PI. XIII.-XVIII.,
and Cyclop. &c. loc. cit. p. 943, fig. 406, 414, 415.

14 This metamorphosis of the nervous system
was first observed by Herold (Entwickelungsgesch.
d. Schmetterlinge, loc. cit. Taf. II.) with Pontia
brassicae , and has since been confirmed by New-
port with Sphinx ligustri and Vanessa urticae ;
see Philos. Trans. 1834, PI. XV. XVI. fig. 20-30,
and Cyclop, loc. cit. p. 962, fig. 420-423.

1-5 See Swammerdamm , Bib. der Nat. p. 207,
Taf. XXII. fig. 6 ( Apis mellifica ) ; Treviranus ,
Biologie, V. Taf. I. ( Bombus muscorum ), and
Brandt and Ratzeburg , Medizin. Zool. IT. p. 203,
Taf. XXV. fig. 31 ( Apis mellifica). For the dis-
position of the ventral chain of the Lepidoptera in
general, see, moreover, L. Dufour , Recherch. sur
les Orthopt., Ilymenopt. &c. p. 381. According to
this last-mentioned naturalist, the nuiriber of ventral
ganglia is five with Vespa, Scolia , and with most of
the Apidae and Andrenidae ; six with Odynerus ,
Sphex , Pompilus , Chrysis , the Ichneumonidae,

* [ § 330, note 17.] See also for a description
and figures of the nervous system of Spectrum

Bembecidae, with Larra, and Tiplica ; four with
Tripoxylon, and three with Eucera.

16 The ventral chain of the Tenthredinidae,
Apidae, Vespidae and other Ilymenoptera, under-
goes, undoubtedly, with the pupae, a metamorpho-
sis similar to that occuring with the Lepidoptera.

17 Swammerdamm, loc. cit. p. 108, Taf. XIV.
(a pupa of Ephemera) ; Marcel de Serres , M4m.
du Mus. IV. 1818, PI. VIII. (1.) fig. 1 ( Acridium );
J. Muller , Nov. Act. Nat. Cur. XIV. Tab. IX.
fig. 4, and XII. p. 568, Tab. L. fig. 1 ( Acridium
and Bacteria) ; Newport , Cyclop. II. p. 950, fig.
409, 410 ( Forjicula and Locusla) ; finally, L. Du-
four, Ann. d. Sc. Nat. XIII. 1828, p. 361, PI.
XXII. fig. 4 ( Forjicula ), Recherch. sur les Or-
thopt. &c. p. 281, PI. II. fig. 7 ( Oedipoda ), and p.
561, PI. XI. fig. 160 ( Libellula ). According to
L. Du four, there are seven ventral ganglia with
Libeliula and Ephemera, while there are only six
with Perla and Phryganea. But Pictet (Re-
cherch. pour servir d l’hist. et dl’anat. des Pliry-
ganides. PI. II. fig. 33-36) and Burmeister
(Handb. &c. II. p. 895, 898) assign to these In-
secta, in both their larva and their perfect state,
eight ventral ganglia. There are even nine of
these ganglia with the Ephemeridae, according to
Burmeister (loc. cit. p. 763). In the very chub-
bed larvae of Myrmeleon there are eight contigu-
ous ventral ganglia beside two thoracic ones (Cu-
vier, Lemons, &c., III. p. 341). Loew ( Germar's
Zeitsch. IV. p. 424) remarks that the proper Neu-
roptera are distinguished by the separation of their
last two abdominal ganglia, while, with all the Or-
thoptera, they are fused together.*

fcmoratum , Leidy , Proceed. Acad. Sc. Philad.
1846, III. p. 83. — Ed.

412

THE INSECTA.

§ 331

not yet been definitely fixed. a8) The first type consists of an absence of
all the longitudinal commissures, as is the case with most of the Lamelli-
cornes, the Curculionidae, and the Scolytidae. Here, the ventral cord is
limited to three ganglia connected together ; of these, the first corresponds
to the prothoracic, and the second, the larger, to the second and third
thoracic ganglia. This last is succeeded by an oblong, ganglionic mass,
representing the concentrated abdominal portion of the cord, and from
which arise the nerves of the muscles of the abdomen.119’ In the second
type, the abdominal portion of the cord occupies the entire length of the
body. This is the case with the Cistelidae, Oedemeridae and Cerambyci-
dae, which have five ganglia in the abdomen. (20) With the larvae of the
Coleoptera, these two types are more clearly defined, there being no inter-
mediate forms. c21>

§ 331.

The Splanchnic nervous system consists, with the Insecta, in all their
states, of a single and a double nervous cord. Sometimes the first, some-
times the second of these is the more developed.

The single Stomato-gastric nerve arises from the anterior border of the
cerebral hemispheres, by two short filaments, which, directly in front
of the brain, meet in a ganglion (Ganglion frontale) lying upon the oesoph-
agus. From this ganglion are given off several nervous filaments which
go to the upper lip ; while, from the opposite side, arises a simple nerve

18 There has recently appeared a very detailed
memoir, accompanied with beautiful figures, on the
nervous system of the Coleoptera, by Blanchard ;
see Ann. d. Sc. Nat. V. 1846, p. 273, Pl.VHI.-XV.,
and R£gne animal, illustr. Insectes, PI. III. III.
bis. and IV. ( Melolontha , Carabus, Otiorhyn-
chus , Cerambyx).

19 See Straus , Consider. &c. p. 391, PI. IX. fig.
1 ( Melolontha vulgaris), and Blanchard , loc. cit.
An analogous concentration of the nervous system
occurs in the families of Histeridae, Gyrinidae,
Nitidulidae, and Scaphididae, where the ventral por-
tion forms a single oblong ganglion, while the three
thoracic ganglia are connected by double longitudi-
nal commissures. In most of the other families, the
three thoracic ganglia are more or less separated,
and the abdominal portion is modified in various
ways. With the Endomychidae, MelpSdae and
Chrysomelidae, there are only four abdominal
ganglia connected by very short double commis-
sures $ see Audouin, Ann. d. Sc. Nat. IX. 1826,
p. 36, PI. XLII. fig. 16 (Lytta) ; Brandt , Mediz.
Zool. II. p. 103, Taf. XVII. fig. 2, Taf. XIX. fig.
19 (Melon and Lytta ) ; Newport, Cyclopaed. loc.
cit. II. p. 950, fig. 408 ( Timarcha ) and Joly,
Ann. d. Sc. Nat. II. 1844, p. 24, PI. IV. fig. 16
(< Colaspis ). With the Dytiscidae, and with Bytu-
rus, there are six abdominal ganglia, and the com-
missures are also very short ; see Burmeister ,
Ilandb. loc. cit. Taf. XVI. fig. 9 { Dytiscus ). This
figure, however, is not fully exact, if compared
with that of Blanchard (loc. cit. p. 343, PI. X. fig.
1). With the Staphylinidae, Silphidae, and Hy-
drophilidae, the abdominal portion, although com-
posed of eight ganglia, is not prolonged much
into the abdomen ; it is longer and composed of
six to seven ganglia with the Carabidae, Lu-
canidae, and Pyrochro'idae •, see L. Dufour ,
Ann. d. Sc. Nat. VIII. 1826, p. 27, PI. XXI. bis,
fig. 2 (Carabus), and Ibid. XIII. 1840, p. 332,
PI. VI. fig. 9 (Pyrochroa). It is even still longer

and composed of eight ganglia with the Elateridae,
Cleridae and Telephoridae.

20 See Blanchard, loc. cit.

21 With those species of the Lamellicornes, and
Curculionidae, whose ventral cord is very much
concentrated, the eleven large component ganglia
are, with the larvae, united into one knotty mass,
without any trace of commissures •, see Swammer-
damm, loc. cit. p. 131, Taf. XXVIII. fig. 1 (Oryc-
tes) ; L. Dufour, Ann. d. Sc. Nat. XVIII. 1842,
p. IV), PI. IV. fig. 11 (Cetonia) ; Burmeister,
Zur Naturgesch. d. Calandra, p. 13, fig. 13, 14 *,
Blanchard , Ann. d. Sc. Nat. loc. cit. PI. Xiy. fig.
1 (Calandra). Writh the larvae of the Melo'idae,
Pyrochro'idae, Lucanidae, Chrysomelidae, Tene-
brionidae, as well as of most of the other families
of the Coleoptera, the ventral chain occupies nearly
the entire length of the body, and is composed of
eleven ganglia having double commissures ; the
thoracic ganglia exceed but little in size those of
the abdomen see Brandt, Mediz. Zool. II. p. 105,
Taf. XVII. fig. 20, Taf. XIX. fig. 31 (Melon and
Lytta)-, L. Dufour, Ann. d. Sc. Nat. XIII. 1840,
p. 327, PI. V. fig. 8 (Pyrochroa), and XVIII.
1842, p. 172, PI. V. fig. 17 (Dorcus) Newport,
Cyclopaed. loc. cit. p. 943, fig. 404 (Timarcha) ;
Joly , Ann. d. Sc. Nat. II. 1844, p. 24, PI. IV. fig.
14 (Colaspis), and Blanchard, Ibid. PI. XV. fig.
7, PI. X. fig. 5 (Chrysomela and Tenebrio). It
is only with the larvae of the Carabidae, Silphidae,
Staphylinidae and Diaperidae, that the ventral
cord, although composed of eight ganglia, does not
extend into the last abdominal segments 5 while
that of the larvae of the Dytiscidae, composed of
seven ganglia, does not reach beyond the middle
of the abdomen 5 see Burmeister, Trans, of the
Entomol. Soc. Lond. I. p. 239, PI. XXIV. fig. 9
(Calosoma) ; Blanchard, Ann. d. Sc. Nat. loc. cit.
PI. IX. fig. 3, 5, PI. XI. fig. 4, PI. X. fig. 2 (Sil-
pha, Staphylinus, Diaperis, and Dytiscus).

§ 331.

THE INSECTA.

413

(. Nervus recurrens ) which passes over the oesophagus to the stomach, giv-
ing off branches right and left. Reaching the stomach, it divides, after
having formed a ganglionic enlargement, into two jmncipal branches.

The double Stomato-gastric nerve consists of one, two, or three pairs of
small ganglia, situated behind the brain, on each side of the oesophagus,
and communicating with each other, with the posterior extremity of the
brain, and with the Nervus recurrens , by delicate filaments. These fila-
ments send fine threads to the oesophagus, and, at certain points, anastomose
with the single nerves.®

With the Hemiptera, a single Splanchnic nerve has been observed, 'and,
for the double system, there has been seen, on each side of the oesophagus,
two small ganglia, one behind the other.1 (2) 3 4

With the Diptera, the splanchnic system appears to be present ; at least,
there has been observed on the Chyliferous stomach of the Ilippoboscidae,
a pair of filaments belonging, probably, to the double system.®

The Lepidoptera have a highly-developed Nervus recurrens , which often
forms, with the caterpillars, several small ganglia lying behind each other
on each side of the brain, and connected together by a double nervous
arch. The double system arises on each side of the oesophagus, from two
ganglia, situated one behind the other, which, with the caterpillars and
pupae, are often approximated to a blending together, and which send off,
beside the filaments anastomosing with the recurrent nerve, threads to the
dorsal vessel.® The Hymenoptera,® Neuroptera, and Orthoptera, also,
have the two kinds of splanchnic systems. The double trunks are highly
developed with the Acrididae, and the Gryllotalpida, and have two pairs
of ganglia at their upper extremity, beside one or two on their course ;
while, with the Libellulidae, Blattidae, and especially the Phasmidae, the
single nerve is the most developed.®

1 For the Splanchnic nervous system of the In-
secta, of which S ivammerdamm. had already ob-
served the recurrent nerve, see, beside the gene-
ral works of Burmeister (Handb. &c. I. p. 308),
and Lacordaire (Introduct. &c. II. p. 214), espe-
cially J. Muller, Nov. Act. Acad. Nat. Cur. XIV.
1828, p. 73 5 Brandt (Isis, 1831, p. 1103, also his
Bemerk. liber die Mundmagen-oder Eingeweidener-
ven d. Evertebr. 1835, p. 16, or Ann. d. Sc. Nat.
V. 1836, p. 95), and Newport , Cyclop. &c. loc.
cit. II. p. 957).

2 Meckel (Beitr. zur vergleich. Anat. I. p. 4)
has observed the Nervus recurrens in the com-
mon Cicada, and Brandt (Bemerk. &c. p. 23, Taf.
II. fig. 1, 2) has observed the same with Lygaeus ,
and at the same time the ganglia of the double
system.

3 See L. Du four, Ann . d . Sc. Nat. III. 1845, p. 67.

4 The recurrent nerve was first discovered in the
silk-worm by S wammerdamm (Bib. der Nat. p.
132, Taf. XXVIII. fig. 3, g.). Subsequently, Ly-
onet (Traite, &c., p.577, PI. XII. fig. 1, PI. XIII.
fig. 1, PI. XVI. fig. 14, PI. XVIII. fig. 1) de-
scribed with the larva of the Goat-moth, the
double system and its relations with the dorsal
vessel. Since then, the two systems have been ob-
served in the larvae, pupae, and imagines of various
Lepidoptera ; see Suckow (Anatom, physiol. Unter-
such. 40, Taf. VII. fig. 33-38, (pupa and imago of
Gastropacha pini )), who has described the double
system and the cardiac nerve. See, also, J. Mul-
ler (Nov. Act. Nat. Cur. loc. cit. p. 97 (the recur-
rent nerve of a larva of Sphinx)), and Brandt
(Isis, loc. cit. p. 1104, Taf. VII. fig. 3, 4, and Be-
merk. &c. p. 20), who has described the two sys-

35*

terns with the imago and larva of Bombyx mori.
The works of Newport (Philos. Trans. 1832, p.
383, PI. XII. XIII., and 1834, p. 389, PI. XIII.
XIV.) on the larva and imago of Sphinx ligustri ,
are very distinguished.

5 See Treviranus (Verm. Schrift. III. p. 59),
who thinks he has observed the Nervus recur-
rens with Apis mellifica ; Brandt, also (Medizin.
Zool. II. p. 203, Taf. XXV. fig. 32, and his Be-
merk. &c. p. 22), has described the two systems in
this species, and in the Bumble-bee (Apis terres-
tris).

<5 According to Burmeister (Handb. &c. I. p.
310, Taf. XVI. fig. 6 (Gryllus migratorius)), the
recurrent nerve leaving the frontal ganglion, runs
backwards and ends, after a short course, in a
ganglion which connects by two filaments with the
internal ganglia of the double system. These
last send off several branches to the cesophagus,
and connect, through two filaments, with the exter-
nal ganglia of the same system. From these exter-
nal ganglia arise two lateral trunks which run
along the oesophagus and are distributed to the
gizzard, forming a nervous plexus having four
ganglia. See, also, for the same species, Brandt ,
in the Isis, 1831, p. 1104, Taf. VII. fig. 5. Accord-
ing to this last author (Bemerk. &c. p. 29, Taf. II.
fig. 7-9), the double system of Gryllotalpa is sim-
ilarly disposed, only the nervous plexus of the giz-
zard arises from two posterior ganglia of the two
trunks. See, also, for that of Gryllotalpa, L.
Dufour, Recherch. sur les Orthopt. &c. p. 285,
PI. III. fig. 22. With Phasma ferula, the four
anterior ganglia of the single system are small, but.
for compensation, the double system is very com-

!

414

THE INSECTA.

§ 332.

The Coleoptera have, in both their larval and their perfect states, a
feebly-developed double nervous system arising from two pairs of ganglia,
and a highly-developed Jfiervus recurrens which, with a few species, forms,
directly behind the Ganglion frontale, a second ganglion. It runs along
the oesophagus, and usually forms, posteriorly, still another ganglion, and
then divides dichotomously.(7)

A great number of the Insecta have, in all their states, another system
of nerves, called Respiratory nerves, which, in view of their functions,
ought very properly to be classed among the mixed nerves, for they con-
tain not only motor, but also vegetative fibres. This system arises by
several single roots from the longitudinal commissures of the ventral cord.
Each of these roots divides into two Nervi transversii which deviate from
each other at right angles, and anastomose with the ganglia of the ventral
chain and with its peripheric nerves, receiving at the same time organic
fibres from the ganglia of the double splanchnic system. These respiratory
nerves are distributed to the large trachean trunks, and especially to the
muscles of the stigmata. The respiratory movements of Insecta cannot,
therefore, be regarded as properly of a voluntary nature.®

CHAPTER IV.

ORGANS OF SENSE.

§ 332.

The sense of Touch appears to be seated, with Insecta, in very different
parts of the body.(1) It is chiefly located in the palpi of the mouth,
which, for this purpose, are usually terminated by a soft surface.® The
antennae, also, serve as tactile organs, but in a very variable manner, ac-

cording to their forms, the degree of

plete ; see Brandt , Bemerk. &c. p. 27, Taf. III.
fig. 1-5, and J. Muller , Nov. Act. Nat. Cur. loc.
cit. p. 85, Tab. VIII. fig. 1, 3. These two anato-
mists have given, moreover, details with figures on
the splanchnic nerves of Libellula, Blatta , Man-
tis and Gryllus.

1 Swammerdamm (Bib. der Nat. p. 132, Taf.
XXVIII. fig. 2) has observed the Nervus recur-
rens in the larva of Oryctes nasicornis. Muller
(Nov. Act. Nat. Cur. loc. cit. p. 94, Tab. VII. fig.
4, 5) has figured it with Luc anus and Dytiscus.
Straus (Consid. &c. p. 406, 391, PI. IX.) has ob-
served with Melolontha , not only the single
nerve, but also the double system which, however,
he mistook for jthe accessory ganglia of the brain ;
Brandt (Mediz. Zool. II. p. 103, 118, Taf. XVII.
fig. 3, 4, Taf. XIX. fig. 20) was the first to under-
stand the true nature of this system with Melot and
Lytta. See, moreover, Burmeister (Handb. &c.
Taf. XVI. fig. 8 (a larva of Calosoma )), Newport
(Philos. Trans. 1834, PI. XIII. fig. 4, 5 (imago and
larva of Timarcha tenebriosa ), and Cyclopaed.
&c. fig. 405, 412, 416-418 ( Timarcha , Meloe and
Lucanus )) ; also Schiodte , in Kr Oyer's Naturh.
Tidskrift. IV. p. 101, PI. I. Acilius.

8 Although Lyonet (Traits, &c., p. 98, 201, PI.

their development, and the habits of

IV. fig. 5, PI. IX. fig. 1) had already described this
respiratory system with the larva of the goat-
moth, under the name of brides dpinidres, it is
Newport who has recently called the attention of
anatomists to this subject, by furnishing, with ad-
mirable details, the disposition of this respiratory
plexus, in the larva, pupa and imago of Sphinx
ligustri (Philos. Trans. 1832, PI. XII. fig. 4,
1834, PI. XIII. &c., and 1836, PI. XXXVI., also
Cyclopaed. loc. cit. p. 947, fig. 400). See, also,
Muller's ideas (Archiv, 1835, p. 82) on the nature
of this nervous system. With various Coleoptera
and Orthoptera, with Locusta , Gryllotalpa , and
Carabus , the single roots arise, according to New-
port, from small ganglia, at the points where are
given off the Nervi transversi.

1 For the senses of the Insecta in general, be-
side the works of Spence and Kirby , Burmeister
and Lacordaire , see Schelver's Versuch einer
Naturgesch. d. Sinneswerkz. bei d. Insekten u.
Wurmern, 1798, a work in which are related the
opinions of the older naturalists on this subject.

2 The tactile sense of the palpi is of great service
to Insecta when they eat*, for these organs are used
not only to feel the food but also to retain, and con-
vey it between the jaws.

§§> 333, 334.

THE INSECTA.

415

the species. These organs receive, each, directly from the superior cerebral
mass, a nerve ; these nerves perceive the slightest disturbances occurring in
the antennal teguments, which are solid and often provided with hairs and
bristles. With those Insecta with which these organs are very long, fili-
form, and movable in various directions, they serve, like the vibrissae of
many mamfrialia, to announce the presence of external bodies. With very
many other Insecta, they are very movable, and are distinctly used as tac-
tile organs, like the fingers of the human hand.® It is also by means of
these organs, that insects perceive the various conditions of the atmos-
phere, especially the temperature, and thereby regulate their move-
ments and actions.

With those Insecta whereof the parts of the mouth are changed into
organs of suction, it is quite evident that the extremity of the snout or pro-
boscis is the seat of a very delicate sense of touch. Also with those female
insects having an ovipositor, which is used to deposit their eggs in holes
of various depth, the apex of this organ must be endowed with the same
power. Finally, this sense must be ascribed to the extremities of the legs
of many Insecta, which, in either their larval or in their perfect state, use
these organs for the performance of labors of a special nature.(4) With the
Poduridae, there is, upon the ventral surface of the first abdominal seg-
ment, a singular organ which is soft, protractile, bifurcated or bi-lobed, and
probably of a tactile nature.®

§ 333.

Undoubtedly the sense of taste, with Insecta, is seated in the tongue,
when this organ is present. The tongue, of a soft consistence, is particu-
larly developed with the Carabidae, Locustidae, Acrididae, Libellulidae,
and Vespidae, which are all mandibulated ; and with the Apidae, and Mus-
cidae, which lick up their food. With the suctorial Insecta, the tongue is
either wanting, or changed into a horny bristle ; — a transformation met
with, also, in certain species having masticatory organs.

§ 334.

The organs of Olfaction with Insecta, have not yet been satisfactorily
determined, although most of these animals by their aid, can perceive in a
most wonderful manner, the food proper either for themselves or their
young. The various hypotheses upon this subject are unsatisfactory, and
especially those by which this sense is located in the hard and dry parts
of the body, which are quite unfit to recognize odoriferous substances. (l)

3 This may be especially observed with the
Hymenoptera.

4 As such I recollect only the Ateuchidae and
Rhynchites among the Coleoptera, the fossorial
Hymenoptera, and the larvae of the Phryganidae
among the Neuroptera.

5 With SmynthuruS) these organs consist of two
long contractile cylinders ; see Degeer , Abhandl.
&c. VII. p. 20, Taf. III. fig. 10, and Nicolet , Re-

* [ § 332, note 5.] See upon the protractile,
tentacular organs of the larvae of the Papiliones,
Kars ten ( Muller's Arch. 1848, p. 375). I have
carefully and microscopically examined these organa

cherch. &c. p. 42, PI. III. fig. 5, 19-22. I am not de-
termined whether or not should be placed in the same
category the soft protractile organs, often of a beau-
tiful red or orange color, possessed by Malachius
on the lateral portions of the body, by Stenus at
the extremity of the abdomen, and by the larvae of
various Lepidoptera ( Papilio machaon and poda-
liriuSj Harpy ia vitiula , &c.) on the neck or back.*
1 According to Rosenthal (ReiPs Arch. X. p.

with Papilio aster ias ; I regard them as odorifer-
ous and defensive, rather than tactile organs. —
Ed.

416

THE INSECTA.

$ 335.

§ 335.

There is the same uncertainty concerning the organs of Audition.
Experience having long shown that most Insecta perceive sounds, this sense
has been located sometimes in this, and sometimes in that orgkn. But in
these opinions, it often seems to have been forgotten or unthought of, that
there can be no auditive organ, without a special auditive nerve which
connects directly with an acoustic apparatus capable of receiving, conduct-
ing, and concentrating the sonorous undulations. (1)

Certain Orthoptera are the only Insecta with which there has been dis-
covered, in these later times, a single organ having the conditions essential
to an auditive apparatus. This organ consists, with the Acrididae, of two
fossae or conchs, surrounded by a projecting horny ring, and at the base of
which is stretched a membrane resembling a Tympanum. On the internal
surface of this membrane, are two horny processes to which is attached an
extremely delicate vesicle filled with a transparent fluid and representing
a membranous labyrinth. This vesicle is in connection with an auditory
nerve which arises from the third thoracic ganglion, forms a ganglion upon
the tympanum, and terminates in the immediate neighborhood of the
labyrinth by a collection of cuneiform, staff-like bodies with very finely-
pointed extremities (primitive nerve-fibres ?), which are surrounded by
loosely-aggregated, ganglionic globules.®

The Locustidae and Achetidae have a similar organ, situated in the

136, Taf. VIII. fig. 5, 6), the olfactory organ of the
Muscidae is a double, oblong fossa, situated under
the antennae, and covered by a plicated membrane
formed by the cutaneous envelope, which is other-
wheres solid and dry. Until lately, from the time'of
Reaumur, the sense of smell has been located in
the antennae, although they present no trace of a
humid surface, and have none of the anatomical
and physiological conditions requisite for being the
seat of this function. See Lefibvre , Ann. d. la
Soc. entom. d. France, VII. p. 395, or Ann.
d. Sc. Nat. XI. 1839, p. 191 *, and Raster , Isis,
1844, p. 647. The same objections might be raised
against the opinion of Marcel de Serres (Ann. du
Mus. XVII. p. 426), who locates this sense, with
the Orthoptera, in the palpi. Equally groundless
appears the view of Raster quoted by Straus
(Consider. &c. p. 420), that this sense is seated in
the stigmata of the tracheae. Treviranus seeks to
avoid the difficulty in supposing that the entire
buccal cavity, which is humid, can receive odorous
impressions. Erickson (Diss. de fabr. et usu an-
tenn. in Insect., Berlin, 1847) has recently appeared
anew in favor of the antennae. According to him,
the numerous small fossae of these organs are cov-
ered internally with a delicate membrane sensible
to odors.*

1 The author who has erred most widely in this
respect, is L. JV. Clarke (Magaz. of Nat. Hist.
September, 1838, or in Froriep's neue Notiz. IX.
p. 4, fig. 12, a-n), who has described at the base of
the antennae of Carabus nemoralis , Illig. an
auditive apparatus, composed of an Auricula , a

* [ § 334, note 1.] See also Burmeister (Zeit.
fiir Zool., Zoot., und Pal&ontol. von D’’ Alton und
Burmeister, No. 5, p. 49, Taf. I. fig. 25-29), who
likewise advocates the auditory function of the
antennae. But Burmeister and Erickson differ

Meatus auditorius externus and internus , a
Tympanum, and a Labyrinthus, of all of which
there is not the least trace. The two white convex
spots at the base of the antennae of Blatta orien-
tals, and which Treviranus (Annal. d. Wetter-
auisch. Gesellsch. f. d. gesammte Naturkunde, I.
lift. 2, p. 169, Taf. V. fig. 1-3) has described as
auditory organs, are, as Burmeister has correctly
stated (Handb. II. p. 469), only rudimentary acces-
sory eyes. Newport (Trans, of the Entom. Soc.
II. p. 229) and Goureau (Ann. d. 1. Soc. ent. X. p.
10) think that the antennae serve both as tactile
and as auditory organs. But this view is inadmis-
sible, as Erickson (Wiesmann's Arch. 1839, II.
p. 285) has already stated, except in the sense that
the antennae, like all solid bodies, may conduct
sonorous vibrations of the air *, but, even admitting
this view, where is the auditory nerve ? for it is
not at all supposable that the antennal nerve can
serve at the same time the function of two distinct
senses.

2 This organ has been taken for a soniferous ap-
paratus by Latreille (M£m. du Mus. VIII. p. 123)
and Burmeister (Ilandb. I. p. 512). J. Muller
(Zur vergleich. Physiol, d. Gesichtssinn. p. 439, and
Nov. Act. Nat. Cur. XIV. Tab. IX.) was the first
who fortunately conceived that with Gryl/us hiero-
glyphus, this was an auditory organ. He gave,
however, this interpretation only as hypothetical j
but I have placed it beyond doubt by careful
researches made on Gompkoceros, Oedipoda, Po -
disma, Caloptenus and Truxalis ( Wiegmann’s
Arch. 1844, I. p. 56, Taf. I. fig. 1-7).

somewhat in their statements upon the intimate
auditory structure of these organs, and, therefore,
as to the exact mode by which audition occurs. —
Ed.

/

§ 336.

TUE INSECTA.

417

fore-legs directly below the coxo-tibial articulation.® With a part of the
Locustidae,® there is, on each side at this point, a fossa ; while with
another portion of this family,® there are, at this same place, two more or
less spacious cavities (Auditive capsules) provided with orifices opening
forwards.® These fossae and these cavities have each on their internal
surface, a long-oval tympanum. The principal trachcan trunk of the leg
passes between the two tympanums, and dilates, at this point, into a vesicle
whose upper extremity is in connection with a ganglion of the auditory
nerve. This last arises from the first thoracic ganglion, and accompanies
the principal nerve of the leg. From this ganglion in question passes off a
band of nervous substance which stretches along the slightly excavated
anterior side of the trachean vesicle. Upon this band is situated a row
of transparent vesicles containing the same kind of cuneiform, staff-like
bodies, mentioned as occurring with the Acrididae. The two large tra-
chean trunks of the fore-legs open by two wide, infundibuliform orifices on
the posterior border of the prothorax, so that here, as with the Acrididae,
a part of this trachean apparatus may be compared to a Tuba Eustachii .(7>
With the Achetidae, there is on the external side of the tibia of the fore-
legs, an orifice closed by a white, silvery membrane (Tympanum), behind
which is an auditory organ like that just described.®

§ 336.

The organs of Vision consist of simple, or of compound eyes.® The
first occur chiefly with the larvae of holometabolic Insecta ; and the second
with Insecta in their perfect state. There are, however, many species
which have both kinds of eyes in their imago state. These organs are
wanting with only a few adult Insecta,® but are wholly absent with many
larvae and pupae of the holometabolic species.®

1. The Simple eyes [Ocelli, Stemmata) are composed of a convex,
spheroidal, or elliptical cornea, behind which is situated a spherical or
cylindrical lens, lodged in a kind of calyx formed by an expansion of the
optic nerve, and which is surrounded by a variously colored pigment-layer,
as by a Ohorioidea.® These stemmata are sometimes so closely situated

3 See my researches in Wiesmann's Arch. loc.
cit. p. 72, Taf. I. fig. 8-17.

4 Meconema , Barbitistes, Phaneroptera , Phyl-
loptera.

5 Decticus , Locusta , Xiphidium , Ephippi-
gera , Saga, Conocephalus , Callinemus , Acan-
thodis, Pseudophyllus , &c.

6 In his classification of the Locustidae, Bur-
meister (I-Iandb. &c. II. p. 673) has made use of
the different forms of these orifices •, — differences,
however, which had before been pointed out by De-
geer (Abhandl. Th. III. p. 285, Taf. XXXVII. fig.
5 and 6) Lansdown Guilding (Linn. Trans. XV.
1827, p. 153).

7 These two infundibuliform orifices of the tra-
cheae, which L. Dufour (Recherch. sur lesOrthopt.
&c. p. 279, PI. I. fig. 2) has called vessies aerosta -
tiques , have generally been regarded as the stig-
mata of the prothorax, although the true stigmata,
of the ordinary form and size, are situated in front
of the orifices ift question.

8 With Ar.heta achat ina and italica , there is
a tympanum of the same size, on the internal sur-
face of the legs in question •, but it is scarcely ob-
servable with Acheta sylvestris , domestica and
campestris

1 For the eyes of the Insecta, see Marcel de
Serres , Mem. sur les yeux comp, et les yeux lisses
d. Ins.-, Treviranus, Verm. Schrift. III. p. 147,
and Beit, zur Anat. u. Physiol, d. Sinneswerkz.
lift. I. p. 84 ; finally, J. Muller , Zur vergleich.
Physiol, des Gesichtssinn, p. 326, or in Ann. d. Sc.
Nat. XVII. 1829, p. 242 (in extract), and his Me-
moir in Meckel's Arch. 1829, p. 38.

2 The eyes are wanting in many species of Ptili -
um which live under the bark of trees {Erichs on,
Naturgesch. d. Insekt. Deutschl. III. p. 32) ; with
Anophthalmus , which live in caverns (Sturm,
Deutschl. Fauna Abth. V. Bd. XV.), and with Cla-
viger, which live in ant-nests.

3 As such may be cited the larvae of Ilymeno-
ptera, excepting, however, those of the Tenthredini-
dae j those of the Diptera, which live in decompos-
ing animal and vegetable substances *, those of the
Elateridae, Histeridae, Lamellicornes, Tenebrioni-
dae, and in general the apodal larvae of Coleo-
ptera 5 finally, the parasitic larvae of the Strepsi-
ptera, whose females are also blind in the imago
state.

4 For the simple eyes of Dytiscus, see Muller ,
in Meckel's Arch. loc. cit. p. 39, Taf. III. fig. 1, 2 ;
for those of Cicada, Vespa, Bombus, and Libel-

418

THE INSECTA.

§ 836.

on the brain that their optic nerves consist only of small papillae on this
last ;(5) but, when further removed from the -brain and grouped together,
the optic nerves arise by a common trunk which divides into as many
branches as there are eyes.®

The number and disposition of the stemmata vary very much in the
different orders. When they alone constitute the visual organs, they are
always situated on the lateral parts of the head, — where they may be
disposed either, as one on each side, or as several irregularly grouped
together ( Ocelli gregati ), or regularly arranged in rows ( Ocelli seriati).
There is only one simple eye on each side with the Pediculidae, Nirmidae,
Coccidae, the larvae of the Phryganidae and Tenthredinidae, and the aquatic
ones of very many Diptera. These organs are in groups of four to eight
with the Poduridae,<7) with the larvae of Lepidoptera, the hexopod larvae
of the Strepsiptera, the larvae of the Hemerobidae, Mymeleonidae, It a phi -
didae, and with the hexapod ones of the Coleoptera.® The winged males of
the Strepsiptera have the largest number of stemmata aggregated in groups ;
they here form two lateral, globe-like projections, and constitute the transi-
tionary form to the faceted eyes, for there are fifty to seventy on each side,
separated from each other only by hairs.® Very many Insecta with two,
faceted eyes, have, also, on their front, three stemmata disposed in a
triangle. (10)

2. The Compound eyes, or those whereof the cornea is faceted, are com-
posed of simple eyes so thickly set together that their more or less thick,
slightly convex, quadi’angular, or hexagonal corneae are contiguous. (1I)

The size of these facets is not uniform even in the same eye, for some-
times those above, or those in the centre, are the larger/1® Behind each
cornea is situated, in place of a lens, a transparent pyramid the apex of
which is directed inwards and received into a kind of transparent calyx
corresponding to a Corpus vitreum. This last is surrounded by another
calyx formed by the expansion of a nervous filament arising from the

lula, see Treviranus , Beitr. &c. p. 84, Taf. II.
fig. 25-35.

5 Bombus, Apis, Vespa) see Treviranus , Bi
ologie, V. Taf. II., and his Beitr. &c. Taf. II. fig. 29 ;
and Brandt and Ratzeburg Medizin. Zool. II. Taf.
XXV. fig. 31,32.

6 With many of the larvae of the Lepidoptera
and the Coleoptera, the optic nerves arise by two
more or less long roots ; see Lyonet , Traits. &c.
p. 581, PI. XVIII. fig. 1, No. 1, and fig. 6 (larva of
the goat-moth) ; Suckow, Anat. physiol. Unter-
such. p. 41, Taf. III. fig. 34 (pine caterpillar), and
Burmeister , Trans. Entom. Soc. I. p. 239, PI.
XXIII. fig. 7 (larva of a Calosoma). The three
stemmata of Cicada receive their nerves from a
common trunk arising from the middle of the brain;
see Treviranus , Beitr. Taf. II. fig. 24, and L.
Du four, Recherch. sur les Hemipt^res, &c., PI.
XIX. fig. 203.

7 See Nicolet , Recherch. sur les Podurelles, loc.
cit. p. 28, PI. II. III.

8 Such are the carnivorous larvae of the Cara-
oidae, Staphylinidae, Dytiscidae, Dermestidae, Sil-
phidae, &c., and the herbiferous larvae of the
Chrysomelidae. Those of Cicindela have only
two large stemmata on each side of the head, and
those of Lycus , Melo<i<, Lampyris and Cantharis ,
have only one.

9 See Templeton , Trans. Entom. Soc. III. p. 54,
PI. IV.

19 There are three frontal stemmata with many
of the Orthoptera (Mantidae, Acrididae, Libelluli-

dae, Perlidae, Psocidae, Ephemeridae and some
Phasmidae) ; with some Neuroptera(//emerofo'ws,
Panorpa , Phryganea ), and Heiniptera ( Penta -
toma , Coreus , Berytus , Cicada). This is the case
also with many Diptera, such as the Muscidae,
Syrphidae, Stomoxidae, Bombylidae, Anthracidae,
Oestridae, Asilidae, Empidae, &c.; they are want-
ing with Tabanus , Haematopota , Conops , Hip-
pobosca , Melophagus , and many of the Tipulidae.
With the Hymenoptera, they are constantly pres-
ent except with the neuter ants and with the fe-
males of Mutilla and Myrmosa ; there are only
two of these eyes with most of GrylLus ; Sciophila ,
Mycetobia and Leja , of the Diptera ; Sesia , Eu~
prepia , Pyralis and a great number of the Noctu-
idae, of the Lepidoptera ; Gryllotalpa , Blatta and
Termes , of the Orthoptera; and Omalium and
Anthophagus , of the Coleoptera.

11 For the intimate structure of the compound
eyes, see Straus (Consid. &c. p. 411, PI. IX.),
Dugis (Ann d. Sc. Nat.- XX. 1830, p. 341, PI.
XII., or in Froriep's Not. XXIX. p. 257), R.
Wagner (JViegmann's Archiv, 1835, I. p. 372,
Taf. V.), and especially Will (Beitrag. zur Anat. d.
zusammengesezten Augen mit facettirt. Ilornhaut.
1840).

12 These differences in the size of the facets had
been observed by Marcel de Serres (loc. cit. p. 45)
with Libellula. They exist also in the eyes of
Lagria Jlava , gibbosa , atra , Tabanus rusticus ,
and some other Diptera ; see Ashton , Trans. En-
tom. Soc. II. p. 253, PI. XXI.

s

§ 337.

TIIE INSECTA.

419

ganglion on the extremity of the optic nerve, a short distance from the
brain. <13) Each lens-like pyramid with its vitreous body and nervous fila-
ment is enveloped by a Chorioidea usually of a brown color, which forms,
behind the cornea, a kind of pupil, <14) but to which are due, by no means,
the beautiful colors so often observed in the eyes of these animals/15'

The size and form of the compound eyes, as also the number of their
facets, are very varied. ae> The larvae and pupae of the hemimetabolic
Insecta have, usually, a less number of facets and consequently smaller
eyes, than the perfect forms. With the Libellulidae, and Diptera, the eyes
are very large ;n7) while with the Formicidae, they are perhaps the smallest
of all. With many Diptera, and some Hymenoptera, those of the males
are much larger than those of the females, and are often contiguous in
front or above/'8’ With some Hymenoptera, and Diptera, they are
pilose, — the hairs being inserted in the angles of the facets/19’

The compound eyes are usually spherical or oblong ; and, with many
Cerambycidae, and with the Vespidae, they are deeply emarginate in front,
or on their internal border. With Diopsis,&0) they have a very singular
appearance, being supported on two very long, rigid, frontal processes, and
their direction cannot, as with other Insecta, be changed without a turning
of the head/21’

CHAPTER V.

DIGESTIVE APPARATUS.

§ 337.

The Insecta very often use their labial and maxillary palpi to seize and
to convey food to the mouth, and even to introduce it wholly within this
last. With many species, the fore-legs are used to seize and retain the
food, and the first pair is sometimes changed for this purpose even into
rapacious organs/1’ With the larvae and pupae of the Libellulidae, there

13 According'’ to Muller (Arch. 1835, p. 613),
these retinae are formed only by a prolongation of
the neurilemma, while the proper nervous sub-
stance does not extend beyond the extremity of the
vitreous body •, but Will denies this ( Muller's
Arch. 1843, p. 349).

14 Each of these pupils, according to Will (Mul-
ler's- Arch. 1843, p. 350), is moved by thirty to
thirty-five delicate fibres which arise on the four
transparent cylinders surrounding the pyramidal
lenses •, but Brants (Tijdsk. voor natuurlijke ge-
schied. en physiologie. 1844, II.) regards them as
trachcan branches and not contractile fibres.

15 The beautiful emerald color of the eyes of
many Libellulidae, Tabanidae, Ilemerobidae, &c., is
due to the corneae ; for the chorioideae are of the
same dead color as those of other Insecta.

16 There are sometimes several thousands of
these facets in the eyes of large size } see Muller ,
Zur verglcich. Physiol, d. Gesichtssinn, &c., p. 340 ;
and Willy Beitrflg. &c. p. 10.

17 The largest eyes are observed with the Ileno-
pidae, where they cover nearly the whole head ;
see Erickson , Entomographien. lift. I. p.132, Taf. I.

18 Among the Hymenoptera, the genera Astata ,
Larray Tachytes , Apis ; and among the Diptera,
the Muscidae, Syrphidae, Leptidae, Tabanidae,
Stratiomydae, and- many other families.

10 With Apis , Tabanus , Anthomyia , Eristalis ,
Volucella , and other Diptera.

20 See hinniy Amoenitates academicae. VIII.
Tab. VI. and Dalman , in Fuessly's Archiv d.
Insekt. lift. 1, Taf. VI. or Isis, 1820, p. 501, Taf. V.

21 The Insecta scarcely move their head when
they look in different directions. This renders very
singular the extended mobility of the head with
Mantis rcligiosa , which, in watching for its prey,
looks on all sides.

1 For example, with Syrtis , Naucoris, Nepa ,
Ranatra , Hemerodromiay Mantis , Mantispa,
&c.

420

THE INSECTA.

§ 337.

is, attached to the under lip, a peculiar prehensile organ which covers, like
a mask, the masticatory organs, and, by means of a double articulation, can
be let down and then returned with the utmost quickness. During this
manoeuvre, the prey is seized by two acute hooks inserted on the anterior
border of this lip, and carried to the mouth.®

The parts of the mouth of the Insecta may be divided into Masticatory
and Suctorial organs, between which, however, there are many intermediate
forms. The second are, properly speaking, modifications of the first, and
for this reason, the last should be described first ; the special details of
these organs, however, belong to the domain of Zoology.

These masticatory organs <:!) consist of a pair of Mandibles and a pair of
Maxillae, which move laterally and are more or less covered by an upper
(Labrum), and an under ( Labium ) lip. The upper jaws ( Mandibulae )
exceed in hardness all the other parts of the masticatory apparatus, and
consist of two simple, horny organs, often denticulated at their extremity.
The under jaws ( Maxillae ) are, usually, softer, and composed of several
pieces, — of which the most essential are : Palpi maxillares, composed of
from one to six articles, and directed outwards ; and the stipule, usually
denticulated or ciliated, and divided into a Lobus ext emus and internus. The
under lip, which supports two Palpi labiales composed of from one to four
articles, may thus be considered as another pair of maxillae the lateral
halves of which are more or less fused together on the median line.®
Such are the oral organs with the Coleoptera, the Neuroptera, and the
Orthoptera. It is interesting to remark that the Orthoptera, in the widest
acceptation of the term, have in common, this character, that their under
lip is divided by a deep fissure into lateral halves, while that of the Neu-
roptera and Coleoptera consists of a single piece.®

At the base of the under lip is attached the tongue, which, either fleshy
or horny, is single or cleft. Often it is completely abortive, but in other
cases, on the contrary, it is very long and changed into a suctorial organ.
This last form is most prominent with the Hymenoptera, where the two
jaws have, at the same time, ceased to be masticatoi'y organs, and form a
sheath enveloping the tongue and labial palpi.®

The oral parts are changed into suctorial organs with the, Diptera,
Hemiptera, and Lepidoptera. The first have a Proboscis, formed b/the under
lip transformed into a suctorial tube [Theca) which is often geniculate.
At its base are from four to six bristles which may be regarded, some as
maxillae and mandibles, and others as representing the tongue.® With

2 See Roesel, Insektenbelustigungen, II. Insec-
fcorum aquatil. Classis II. p. 12, Taf. III. IX., and
Suckow , in Heusinger’s Zeitsch. d. organ. Physik.
II. Taf. I.

3 Beside the so often cited writings of Straus ,
Kirby and Spence , Brandt and Ratzeburg , Bur-
meister , Lacordaire , Newport , and JVestwood ,
see Savigny, M£m. sur les anim. sans verWbres, L.
p. 1, PI. I.-IV.-, also, Isis, 1818, p. 1405, Taf. XVIII.
Nees von Esenbeck , Isis, 1818, p. 1386, and
Suckow , in Heusinger’s Zeitsch. &c. III. Taf. l.-IX.

4 This opinion, before advanced by Oken, Savig-
ny , and Leach, has been sustained with very many
details by Brulli (Ann. d. Sc. Nat. II. 1844. p. 324).

5 On account of these modifications of the under
lip, to which j Erickson (Entomograph. lift. 1, p.
5, and in Germans Zeitsch. I. p. 1.50, Taf. II.) has
especially called the attention, we can distinguish,
in their perfect state, the hemimetabolic from the

holometabolic Neuroptera. This justifies the sepa-
ration we have made of the first whose pupae take
food and are active, from the second whose pupae
are inactive and do not eat. We have placed these
last among the Orthoptera, because, like them, they
have in all their states a bifid under lip. The dif-
ferences between the under lip of the Orthoptera
and that of the Neuroptera are well shown in Savig-
ny1 s excellent figures of the buccal orga-ns of these
insects (Descript, d. l’Egypte, Orthopt£res, PI. I.-
VII. and N europt^res, PI. I. -II I.

6 See Swammerdamm , Bib. der Nat. Taf. XVII.
fig. 5 •, Treviranus , Verm. Schrift. II. lift. 2, p.
112, Taf. XII.-XIV. ; Brandt and Ratzeburg ,
Mediz. Zool. II. Taf. XXV. fig. 8-16 •, Newport ,
Cyclop, loc. cit. p. 897, fig. 375, 376 ; but especially
Savigny , Descript, de l’Egypte, Hyraenopt^res, PI.
I.-XX.

1 See Savigny , Mem. sur les anim. sans vert£-

§337.

THE INSECTA.

421

the Hemlptera, the suctorial apparatus is lengthened into a Rostrum , by
the under lip being changed into two quadri-articulate grooves united so
as to form a tube, and enclosing the setiform mandibles and maxillae.®
With the Lepidoptera, the changes are still greater, for the mandibles are
only very small appendages, while the maxillae are transformed, each, into a
semi-canal which can be rolled up spirally, and when united form an organ
of suction ( Lingua spiralis ). At the base of this last are two very short
maxillary palpi, bi- or tri-articulate, while the two tri-articulate and very
hairy labial palpi consist of two pretty large appendages between which the
suctorial tube retreats when rolled up.®

The buccal organs begin to atrophy with the Aptera. The four palpi
present with the Lepismidae, are already wanting with the Poduridae ;a0)
and with the Nirmidae, they, as well as the maxillae, are very small, while
the mandibles are quite large.

With the Pediculidae, there are still wider modifications ; for here there
is a protractile suctorial tube composed of four stiff bristles (rudimentary
jaws) which are enclosed in a soft and equally protractile sheath (under
lip.)<®

With the Larvae of Insecta, the buccal organs are most usually masti-
catory ; for, not only the larvae of the Coleoptera, the Orthoptera, and many
of the Neuroptera and Hymenoptera, have the same organs of this kind (mas-
ticatory) as the perfect insects/® but also the larvae of the suctorial Lepidop-
tera,(13) and those with a distinct head of certain Diptera (14) with which, how-
ever, the maxillae and palpi are very frequently wanting/® But with the
acephalous larvae of Diptera, those of the Strepsiptera, as also with the
parasitic ones of some Hymeiioptera, the mouth is formed rather for suck-
ing than for masticating the food ; for, on the inner side of the soft tumid
lips, either the horny organs are wholly wanting/® or the mouth is armed
with two parallel hooks, which are used partly to grapple and partly to
puncture the bodies these animals attack/®

bres, I. PI. IV. fig. 1, and Newport , Cyclopaed.
loc. cit. fig. 379-381.*

8 Savigny , M6m. &c. I. PI. IY. fig. 2, 3 •,
Ratzeburg , Media. Zool. II. Taf. XXVII. •, and
Burmeister , Ilandb. &c. ll. Taf. I.

9 This suctorial tube is pretty long with the Papi-
lionidae and the Sphingidae ’, it is very short with
many Bombycidae and Pyralidae ; see Savigny ,
M6m. &c. I. p. 1, PI. I. -III. Ratzeburg , Die
Forstinsekt. II. p. 2, Taf. I. •, and Newport ,
Cyclopaed. loc. cit. p. 900, fig. 377, 378.

19 Nicolet , llecherch. p. 34, PI. I V.

11 Burmeister , Linnaea entomologica. II. p. 569,
Tab. I.

DJ See Ratzeburg , Die Forstinsekt. I. III. *,
Hartig , Die Aderfliiger Deutschlands, Taf. I.-
VIII. -, Burmeister, Trans. Entom. Soc. I. PI.
XXIII. XXIV. ( Calosoma ), and Naturgesch. d.
Calandra, fig. 10-12 ; Waterhouse, Trans, entom.
Soc. I. PI. III.-V. ( Rliaphidia , and various Coleop-
tera).

13 Lyonet , Traits, &c., PI. II. j and Ratzeburg,
Die Forstinsekt. II. Taf. I.

* [ § 337, note 7.] See in this connection the me-
moir of Blanchard (De la Composition de la bouche
dans les Insectes de l’ordre des Dipteres, in the
Compt. rend. 1850, XXXI. p. 424), who shows that

36

14 Such are the larvae of Culex, Chironomus,
Corethra and Simulia, and many other of the
aquatic Tipulariae.

15 In the larvae of Sciara, Mycetophila, S'cio-
phila, Ceroplatus, &c., which live in rotten wood
or in fungi *, see L. Du four, Ann. d. Sc. Nat. XI.
1839, p. 204, PI. V. fig. 23, XII. p. 10.

19 The mouth of the apodal larvae of the Strep-
siptera (see my researches in Wiegmann's Arch.
1843, I. p. 159, Taf. VII. fig. 14), and of the young
larvae of Microgaster ( Ratzeburg , Die Ichneu-
mon. d. Forstinsekt. p. 13, Taf. IX.) has, in place
ofjaws, soft papillae which, as these larvae ap-
proach the end of their development, are changed
into horny jaws by means of which these Insecta
make a passage into the skin of the animals in
which they live.

17 With the Muscidae, Oestridae, Syrphidae, and
other Diptera 5 see Swammerdarrim , Bib. der
Nat. Taf. XLIII. fig. 5, and L. Dufour, Ann. d.
Sc. Nat. I. 1844, p. 372, PI. XVI. fig. 8, 10, XII.
1839, p. 4, PI. II. III.

the mouth of the Diptera presents appendages
wholly comparable to those of the other Insecta,
except that these appendages are modified in a
special manner. — Ed.

422

THE INSECTA.

§ 338.

The mouth of the larvae of the Myrmeleonidae, Hemerobidae, and
Dytiscidae, is of a very peculiar construction. There is no oral orifice,
properly speaking, and the maxillae and mandibles are wholly unfit for
mastication, the latter being changed into two curved hooks, hollow and
with a narrow fissure at their extremity. These larvae bury these hooks
in the insects they have seized, and through the cavity of these organs, which
communicates at its base with the oesophagus, suck the blood. (18)

A considerable number of the Insecta take no food during their perfect
state, the object of their existence being only to accomplish the act of repro-
duction. Their jaws are often very rudimentary and are fit neither for suck-
ing nor for masticating. (19) In some cases, indeed, not only are these organs
wanting, but the oral orifice is closed as with all inactive pupae. (20)

§ 338.

The Digestive Canal of Insecta and their larvae, is more or less long,
sometimes extending from the mouth directly to the anus upon the median
line ; sometimes forming in the abdomen loops and convolutions. It is
retained in place not by a mesentery, but by numerous fine tracheae,
which envelop its entire extent. It is always wholly invested by a homo-
geneous peritoneal envelope under which lies a muscular tunic, composed
of longitudinal and circular fibres, which are especially developed about the
mouth and anus. Internally, it is lined throughout by an epithelium which
is extremely thin at the middle portion of this canal, but very solid and
composed of chitine at its two extremities. In the middle portion just
mentioned, there is a layer of aggregated cells, evidently of a glandular
nature, between the epithelium and the muscular tunic.

The different parts of this canal in the Insecta may be properly distin-
guished in the following manner. The first portion is the Oesophagus,
muscular, occupying the three thoracic segments and often dilated at its
posterior part into a crop ( Ingluvies ) and muscular gizzard [Proventriculus) .
Sometimes there is appended to the oesophagus a sucking stomach consist-
ing of a more or less pedunculated, thin-walled vesicle, which is multiplicated
on itself when empty.

The second portion consists of a stomach ( Ventriculus ), in which the
chyle is formed, and which is continuous at the point of insertion of the
Malpighian vessels, with the third portion of the digestive canal. This
third portion commences by a small and usually short Ileum, which is fol-
lowed by a Colon, larger and of variable length. This last often has a
Caecum at its anterior extremity and terminates posteriorly in a short mus-
cular Rectum.m

18 See Roesel , Insektenbelust. III. Taf. XVII.
XVIII. ( Myrmeleon ), II. Insect, aquit. classis I.
Taf. I.-III. (Dytiscus) ; Ratzeburg , Forstinsekt.
III. Taf. XVI. ( Hemerobius ). With the larva of
Dytiscus , the body of the maxillae is wholly abor-
tive, but always provided with palpi. With those
of Hemerobius , the maxillae are small, deficient in
palpi, and play in a groove on the concave side of
the mandibles ; finalty, with those of Myrmeleon ,
these organs are wholly enclosed in the cavity of
the mandibles.

19 The maxillae are rudimentary and very soft
with the Ephemeridae, and Phryganidae, in the
last stages of their development. The very short

proboscis of many Bombycidae and Hepiolidae, ap-
pears equally unfit to receive food. Finally, the two
small, intercrucial maxillae of the males of the
Strepsiptera, are wholly inadequate for the func-
tions of masticatory organs.

20 Movable oral organs and an oral orifice are
wanting with many Oestridae, and Henopidae, as
well as with the male Coceidae.

1 The functions of these different portions of the
digestive canal do not always correspond to those
of those parts having the same names with Verte-
brata. Rurmeister (Zur Naturgesch. d. Calandra
p. 9) is certainly correct in saying that the stomach
is the chylopoietic part, thus combining the fuuc-

§ 338.

THE INSECTA.

423

With nearly all Inseeta in their perfect state, this colon or large intestine
contains from four to six organs of a peculiar structure and doubtful
function. These consist of transparent protuberances, disposed in successive
pairs, or forming a transverse series. They are round, ovoid, or oblong,
their base being sometimes surrounded by a horny ring, and they are trav-
ersed by numerous tuft-like tracheae. <2) The Lepidoptera, especially, are
remarkable for their numerous organs of this kind. <3> It is singular that
they are wanting in all insects during their larval and pupa states.

The Anus of Inseeta, in all their states, is invariably situated on the last
segment of the body. With the quiescent and non-feeding pupae, both the
anus and the mouth are wanting, but with the larvae of only the Strepsip-
tera, the Apidae, and the Yespidae, are both ileum and colon wanting at
the same time.®

The form and disposition of the different parts of the digestive canal
vary infinitely, according to the habits of life and the states of development
of the Inseeta in which they are observed. On this account it is very
difficult to make any general statement of the various structural relations.®
But that condition may be taken as the fundamental type which belongs
to those perfect insects whose life is pretty long and which have masticatory
organs. Such, therefore, will receive our first consideration.

With the Coleoptera,® the oesophagus is nearly always terminated by a

tions of the stomach and small intestines of the
Mammalia. The crop and gizzard correspond to
parts of the same names with birds. The ileum,
which is usually regarded as analogous to the small
intestine of the Vertebrata, probably plays a very
subordinate part in the act of digestion. Burmeis-
ter thinks that it serves only to conduct the chyme
or chyle, but with certain species where it is very
long, it is probably the seat of a second digestion.
The caecum often serves to receive the secretory
product of the Malpighian vessels, and therefore
belongs rather to the urinary than to the Chylo-
poietic apparatus (see § 346).

2 It is hardly comprehensible how organs so com-
‘mon with the Inseeta, should, as yet, be so little
known.

Swammerdamm , however, observed them with
Apis mellijica (Bib. der Nat. Taf. XVIII. fig. 1),
and Suckow (Heusinger's Zoitsch. III. p. 21, Taf.
V I. fig. 121, 128) has mentioned them with Vespa
crabro , and Apis mellijica , under the name of
callous swellings. Brandt and Ratzeburg , Mediz.
ZjoI. II. Taf. XXV. fig. 2D ( Apis mellijica ), as
well as Burmeister (Handb. &c. I. p. 149) speak
of them very slightly. L. Du four (Recherch.
sur les Orthopt. &c. p. 396, 427), has figured them
with various Orthoptera, Neuroptera and Ilyrnen-
optera under the name of Boutons charnus ;
finally, Newport (Cyclopaed. &c. II. p. 970, fig.
421, (Carabus monilis)) has designated them as
Glandular protuberances. All the figures above
cited give the external form of these organs but not

* [ § 334, note 4.] See, for the intestinal canal of
the larvae of Hymenoptera, Ed. Grube ( Muller's
Arch. 1849, p. 50), who, from examinations of the
larvae of wasps and hornets, concludes that a
ftraight alimentary canal opening at the posterior
extremity is always present, but that only the mus-
t ular tunic forms the continuous tube, — the Lining
membrane of the stomach ending caecaily, and the

their internal structure. They are especially ap-
parent and four in number with the Muscidae ; see
Ramdohr , Abhandl. iib. d. Verdauungswerkz. &c.
Taf. XIX. fig. 2, M. M. } and. Sucko w , loc. cit.
Taf. IX. fig. 153. The four with Melophagus are
very singular and different from those of tiie other
pupiparous Diptera, iu that their external surface
is covered with small solid scales , see L. Dufour ,
Ann. d. Sc. Nat. III. 1845, p. 71, PI. II. fig. 13-
15.

3 I have counted, with the Zygaenidae, thirty of
these swellings, and nearly a hundred with the
Papilionidae, Noctuidae and Geometridae. Ilepio-
lus , Tinea , and Adela , have, by exception, only
six. Treviranus (Verm. Schrift. II. p. 106, Taf.
XII. fig. 4), and Lyonet (M£m. du Mus. &c. XX.
p. 184, PI. XVIII. fig. 6) have taken these organs
for glands with Papilio.

4 The digestive canal is probably organized in a
similar manner with the larvae of the Hymenoptera
and the Diptera, which are parasitic in the bodies
of other Inseeta.*

b For the digestive tube of the Inseeta, beside the
works already cited of Swammerdamm , Gaede ,
Burmeister , Lacordaire , and Newport, see,
especially, Ramdohr , Abhandl. iib. d. Verdauungs-
werkz. &c. 5 Marcel de Serres , Ann. du Mus.
XX. p. 48 ; and Suckow , in Heusingcr's Zeitsch.
III. p. 1.

6 The digestive organs of the Coleoptera have
been especially studied by L. Dufour ( Ann. d. Sc.
Nat. II. III. 1824, and I. 1834). See, moreover,

same membrane of the intestine commencing cae-
cally, and, finally, that the intestine serves, during
the larval state, only to receive the secretion of the
Malpighian vessels which are urinary organs. But
it is doubtful if the contents of the stomach are ex-
pelled by mouth during the larval state. This closed
pyloric end of the stomach is opened during the
transition to the pupa state. — Ed.

424

THE INSECTA.

$ 338.

crop-like dilatation, m winch, with the Cicindelidae, Carabidae, Dytiscidae,
and Gyrinidae, is followed by an ovoid gizzard. This last is longitudinally
plicated internally, and these folds are usually armed on their borders with
cilia or horny hooks. The intestinoid stomach is of median length with
the carnivorous Coleoptera, but very long and more or less flexuous with
those which are herbivorous.® Nearly always, its whole external surface
is numerously constricted, and covered with small caeca.® The ileum and
colon are, usually, rather short. a0)

Among the Orthoptera, the families Forficulidae, Termitidae, Blatti-
dae, Achetidae, Locustidae, Acrididae, and Mantidae, are distinguished for
their large crop,<U) which, with Gryllotalpa is completely constricted from
the oesophagus. The gizzard is of variable length, and covered, internally,
with rows of horny denticulated plates. (12) The stomach is tubular, of equal
calibre, median length, and rarely makes a half or an entire turn.(13)
In most of the families just mentioned, its upper extremity has two, six, or
eight caeca, a4) and its posterior part is continuous into an often somewhat
flexuous ileum upon which succeeds a short colon. With the Perlidae, the
gizzard is wanting, but the upper extremity of the stomach has from four to
eight caeca, pointing forwards. <I5> With the Phasmidae, and the Libelluli-
dae, the oesophagus is long and large, and protrudes somewhat' into the
straight, oblong, constricted stomach, which is without caeca and is succeeded
by a very short ileum and colon. a0) The digestive tube of the Ephem-
eridae, which, in their perfect state, take no food, is feebly developed.
Its walls are very thin throughout, and the oesophagus is directly continu-
ous with the stomach which is a bladder-like dilation and succeeded by a
short, straight intestine. <17)

Ramdohr , Magaz. d. naturf. Freunde zu Berlin,
1807, p. 207, Taf. IV. {Cardbus) ; Brandt , Mediz.
Zool. II. Taf. XVII. XIX. (Melon and Lytta) ;
Straus , Consider. &c. PI. V. ( Melolontha ).*

7 With Oedemera , this crop is constricted from
the stomach *, see L. Dufour , loc. cit. III. PI.
XXX. fig. 7, 8.

8 The stomach is of the greatest length with the
Melolonthidae and Ilydrophilidae see Straus, loc.
Cit. PI. V., and Suckow , loc. cit. II. Taf. III. IV.

9 This constricted stomach is especially observed
with the herbivorous Coleoptera, as, with Melon,
Lytta, and Cantharis ; but is wholly wanting with
Iajcus, Telephorus , Malachius, and Cistela.
With the Elateridae, the stomach is smooth, but, at
its upper extremity there are two caecal folds,
which, with the Buprestidae, are very long *, see
L. Dufour, loc. cit. III. PI. XI. fig. 1, 3, 4 ;
Meckel, Beitr. &c. I. Hft. 2, p. 129, Taf. VIII. fig.
5*, and Gaede , Nov. Act. Nat. Cur. XI. p. 330,
Tab. XLIV. fig. 1.

10 With the Dytiscidae, a pretty long and small
caecum extends forwards from the rectum ; see
Ramdohr, Abhandl. &c. Taf. II. ; L. Dufour,
loc. cit. III. PI. X. fig. 3, and Burmeister , lland-
buch, &c.,I. Taf. X. fig. 4.

11 See Ramdohr, Abhandl. &c. Taf. I. 5 Marcel
de Serres, loc. cit. PI. I.-III. 5 Gaede , Beitr. &c.
Taf. I. II. (Blatta and Acheta ) ; Suckow, loc. cit.
III. Taf. VII. fig. 134-136 ( Gryllotalpa ) ; Bur-
meister, Handb. &c. I. Taf. XI. fig. 1-6 5 and L.
Dufour , loc. cit. XIII. 1828, p. 350, PI. XX.

* [ § 338, note 6.] See, also, Leidy, loc. cit.,
Flora and Fauna within Animals, &c., for full de-

(Forficula), and his Recherch. sur les Orthopt.
&c. loc. cit. PI. I.-V. XIII.

12 See the figures cited in the preceding note.
According to L. Dufour (Recherch. kc. p. 608,
PI. XIII. fig. 196), this gizzard with its dental ap-
paratus is wanting with Termes ; but, according
to Burmeister (Ilandb. I. p. 137, Taf. XI. fig.
8-10), it is present being concealed at the base of
the oesophagus.

13 Gryllotalpa and Ephippigera.

14 The^e caeca are wanting with Forficula and
Termes. There are only two with Acheta , Gryl-
lotalpa, Locusta, and Ephippigera ; six to eight
with the Mantidae, Blattidae, and Acrididae. In
these last, each of these caeca sends off two dever-
ticula. one forwards, and the other backwards.

15 See Suckow, in Heusinger\s Zeitsch. II. p.
267, Taf. XVI. fig. 7 L. Dufour, Recherch. &c.
PI. XIII. fig. 198 ; and Pictet, Hist. Nat. des
Nevropt^res. Famille des Perlides. These caeca
are wanting with Nemura.

16 See Ramdohr, Abhandl. &c. Taf. XV. ( Libel -
lula and Agrion ) ; Suckow , loc. cit. II. Taf. II.
fig. 14 (Aeschna) ; L Dufour, Recherch. &c. p.
568, PI. XI. ( Aeschna and Li be llula) ; and Mul-
ler, Nov. Act. Nat. Cur. XII. p. 5y1, Tab. L.
(Bacteria). These stomachic appendages are
wanting with Psocus also 5 see Nitzsch, in Ger-
mans Mag. IV. p. 277, Taf. II. fig. 1.

17 See L. Dufour, Recherch. &c. PI. XI. fig.
167, and Pictet , Hist. Nat. des Insect. N6vropt.
Famille des Eph£merines.

tails of the intimate anatomy of the alimentary
canal of Passalus cornutus. — Ed.

$ 338.

THE INSECTA.

425

The predatory Panorpidae, which are rapacious, differ notably from the
other Neuroptera, and resemble rather the preceding order. Their oesoph-
agus is short and straight, and, in the thorax, is succeeded by a spherical
muscular gizzard which is lined internally with a brown chitinous membrane
covered with stiff hairs. The stomach is tubular and straight ; the ileum
makes two convolutions before passing into the long colon. <18) With the
other Neuroptera, namely, the Myrmeleonidae, Hemerobidae, Sialidae, and
Phryganidae, the oesophagus is long, and dilated, posteriorly, into a kind of
pouch ; and often there is a long, thin-walled, sucking stomach inserted on
one of its sides. The proper stomach is of a median length, and is more
or less transversely constricted. <19) The two other portions of the digestive
canal are very small and straight.

The Ilymenoptera, which often sip up their fluid flood, have a long oesoph-
agus which dilates into a thin-walled, sucking stomach.™ With the
Vespidae, Apidae, and Andrenidae, this stomach is often only a lateral
fold of the oesophagus, and with many Crabonidae, it is attached solely by
a short and narrow peduncle.™ Many species of this order have a rudi-
mentary, callous gizzard, enveloped by the base of the stomach. In the
genera Formica, Cynips, Leucospis and Xyphidria, it is very apparent,
and consists of a globular, uncurved organ. Those Ilymenoptera which are
engaged during a long and active life (22) in labors for the raising and sup-
port of their young, have a pretty long andflexuous stomach and intestine,
and the first has, usually, many constrictions. The Cynipidae, Ichneu-
monidae, and Tenthredinidae, which, after copulation and the deposition of
their eggs, take no further care in the act of reproduction, have only a very
short small stomach and intestine.

But the modifications of each of the various portions of the digestive
tubes are most prominent with the sucking Insecta, especially with the
Hemiptera.<23) The oesophagus of these last is usually short and small,
while the stomach is generally very long, and describes many convolutions
in the abdominal cavity. This stomach, as to form and structure, may be
divided into two or three distinctly-defined portions. The first consists of
a glandular ante-stomach which is straight, large, and divided by several
constrictions. The second has the form of a long, flexuous canal, whose
walls are glandular, and which dilates, at its posterior extremity, into an
oval pouch.™ With the Cicadidae, it forms a kind of loop, its posterior
extremity being attached to the ante-stomach with Tettigonia, Cercopis, and

18 Ramdohr, Abhandl. &c. p. 150, Taf. XXVI.
fig. 1, and L. Du four, Ilecherch. &c. p. 582, PI.

XI. fig. 169.

ID Ramdohr, Abhandl. &c. Taf. XVI. fig. 2, Taf.
XVII. fig. 2, 6 •, L. Dufour , Recherch. &c. PI.

XII. XIII . ; and Pictet , Recherch. pour servir &
l’hist. et & I’anat. des Phryganides.

The Myrmeleonidae and Hemerobidae, alone,
have a spherical callous gizzard situated between
the stomach and oesophagus.

20 See Swammerdamm , Bib. der Nat. Taf.
XVIII. fig. 1 *, Treviranu.fi , Verm. Schrift. II.
Taf. XIV. XVI. ; Brandt and Ratzebur g- , Mediz.
Zool. II. Taf. XX V. fig. 29 ; Ramdohr , loc. cit.
Taf. XI I. -XIV. ; Suckow , loc. cit. III. Taf. VI.
VI I. VIII. ; finally, L. Dufour , Ilecherch. &c. p.
389, PI. V.-X.

21 With Chrysis , and Hedychrum , this sucking
stomach consists of two lateral caeca situated at the
lower end of the oesophagus *, see Suckow , loc.
cit. III. Taf. IX. fig. 155, and L. Dufour , loc. cit.
PI. IX. fig. 113, 116.

22 The Apidae, Andrenidae, Vespidae, and Lar-
ridae.

23 For the digestive apparatus of the Ileiniptera,
see Ramdohr , Abhandl. &c. Taf. XXII. XXIII. j
Suckow , loc. cit. III. Taf. VII. VIII. ; L. Du-
four, Recherch, sur les Heinipt<h-es. p. 20, PI. I.-
IX.*

24 Notonecta , Naucoris , Velia , Lygaeus , Co-
reus , Pyrrhocoris , Pentatoma , Tetyra , Syro-
mastes , &c.

* [ § 338, note 23.] For the digestive appara-
tus with all its details of Belostoma , see Leidy ,

3(3*

Proc. Acad. Nat. Sc. Philad. I. 1841, p. 62. — Ed.

426

THE INSECTA.

§ 338.

Ledra ; and with Cicada, it penetrates even under the muscular tunic of this
ante-stomach. (25) With the Pentatomidae, and some Coreidae, there is even
a third stomach, quite remarkable, consisting of a very narrow, slightly-
flexuous canal, on which are inserted two or four rows of closely-aggregated
glandular tubes. <26> The ileum and colon are nearly always fused into a
pyriform pouch, upon which is sometimes inserted a kind of lateral cae-
cum.(27) With the Cicadidae, however, the ileum is distinct, narrow, and
nearly always very long and flexuous.

The Diptera have a. sucking stomach with a more or less long peduncle,
inserted upon one of the sides of the short, small oesophagus. This pedun-
cle accompanies the stomach even into the abdominal cavity, where it ter-
minates in a pouch whose thin walls are composed solely of delicate muscular
fibres. This pouch is oblong or round, and often divided, heart-shaped, by
a deep fissure/281 The proper stomach is always long and intcstinoid,
except at its anterior extremity, where it is often dilated. It is situated
in the abdominal cavity and makes many convolutions. In some families,
only, there are two lateral caeca inserted near its cardiac extremity. (29> The
ileum is small, of median length, and is succeeded by a pyriform colon.

The Lepidoptera, which, in their perfect state, live only upon the juices
of flowers, suck up this kind of food by means of a thin-walled, sucking
stomach, situated at the anterior extremity of the abdominal cavity, and
opening by a short peduncle into the posterior extremity of the small, long
oesophagus.0301 The stomach is pretty long and large, often varicose, and
always straight. The ileum is long, small, and nearly always forms several

25 See Ramdohr , loc. cit. Taf. XXIII. fig. 3 *,
Suckow , loc. cit. Taf. VII. fig. 138 •, and L. Da-
four , loc. cit. PI. VIII. or Ann. d. Sc. Nat. V.
1825, p. 157, PI. IV. It was formerly thought that
the second stomach of Cicada opened into the ante-
stomach, but the true relation of these organs has
been pointed out by Doy&re (Ann. d. Sc. Nat. XI.
1839, p. 81, PI. I.) and confirmed by L. Dufour
(Ibid. XII. p. 287). The annular stomach of Dor-
thesia and Psylla is probably arranged in the
same manner ; see L. Dufour , R.echerch. &c. loc.
cit. PI. IX. fig. 108, 110.

20 There are four rows of these glands with
Pentatoma, and Tetyra , and two, only, with
Syromastes , and Coreus ; see Ramdohr , loc. cit.
p. 189, Taf. XXII. fig. 3, 4 *, L. Dufour , Recherch.
&c. p. 21, PI. I. II.

These two authors have taken these rows of
glands for transverse-plicated semi-canals. Tre -
viranus (Annal. d. Wetterauisch. Gesellch. &c. I.
lift. 2, p. 175, Taf. V. fig. 4) is still more mistaken
in taking the four rows in Pentatoma rufipes , for
as many adjacent, but distinct intestinal tubes.

27 Coreus , Pelogonus , Ranatra , and Nepa.

28 The sucking stomach is simple with the Tipuli-
dae, and Leptidae ; it is cordate with the Tabani-
dae, Syrphidae, and Muscidae $ see Ramdohr , and
Suckow , loc. cit. 5 Treviranus, Verm. Schrift.
II. p. 142, Taf. XVII. •, and L. Dufour , Ann. d.
Sc. Nat. I. 1844, p. 376, PI. XVI. fig. 12.

29 With the Tabanidae, these two caeca point
forwards 5 but with the Leptidae and Bombylidae,
backwards 5 and with the Syrphidae, there are
four of them, varicose, two pointing forwards

* [ § 338, note 30.] See, also, for the intimate
structure of the intestinal canal and its append-
ages of Bombyx mori (both larva and imago), Fil-

and two backwards. The Diptera fill this sucking
stomach with liquid (honey, blood, &c.), or solid
(pollen-grains) substances, but which, certainly, are
only there deposited without being changed, for
the walls of this organ do not present the least
traces of a glandular structure. It is, moreover,
remarkable that the Pulicidae and the Ilippobosci-
dae, which feed exclusively on animal juices, have
a kind of crop at the posterior extremity of the
oesophagus, but no trace of a sucking stomach 5
see Ramdohr , loc. cit. Taf. XXI. XXIII. ( Melo -
phagus and Pulex), also L. Dufour , Ann. d. Sc.
Nat. VI. 1825, p. 303, PI. XIII. fig. 1, and III.
1845, p. 69, PI. II. fig. 13 ( Hippobosca and Melo-
phagus). With Pulex, the crop is provided with
large cilia on its internal surface, and thus resem-
bles a gizzard.

30 See Swammerdamm Bib. der Nat. Taf.
XXXVI. fig. 1 (Vanessa urticae) ; Treviranus ,
Verm. Schrift. II. p. 103, Taf. XI., and Annal. d.
Wetterauisch. Gesellsch. III. lift. 1, p. 147, Taf.
XVI. ( Vanessa , Sphinx, and Deilephila ) ; Suck-
ow, loc. cit. Taf. IX. fig. 161 (Y ponomeutd) ; and
Newport, Cyclop, loc. cit. fig. 430, 431 (Sphinx
and Pontia). This sucking stomach is double
with the Zygaenidae (Ramdohr, loc. cit. Taf.
XVIII. fig. 1) ; it is wholly wanting with the Ile-
pialidae, Bombycidae,and in general all the imago
Lepidoptera which do not eat. See Treviranus ,
Verm. Schrift. loc. cit. p. 107, and Annal. d.
Wetterauisch. Gesellsch. loc. cit. p. 158, Taf. XVII- •,
and Lyonet, M6m. du Mus. XX. p. 208, PI. XIX.
fig. 10.*

ippi, Annali della R. Accad. d’agricoltura di To-
rino, V., or Wiegmann's Arch. 1851, Th. II. p.
217. — Ed.

§ 338.

THE INSECTA.

427

convolutions. The colon is constantly of a large size, and is often dilated
into a caecum at its anterior portion/31'

Among the Aptera, the Nirmidae, Poduridae, and Lepismidae, have, at
the posterior extremity of the oesophagus, a kind of crop, which, with
Lepisma , is succeeded by a globular gizzard provided with six teeth. The
proper stomach has the form of a long tube, and is not flexuous as with the
Pediculidae. With these last, and with the Nirmidae, which are parasites,
it has, at its anterior extremity, two caeca directed forwards. But the
intestine which succeeds it, is very short with all the Aptera/32'

With all the hemimetabolic Insecta, or the Orthoptera and Hemiptera,
the digestive canal of the larvae and pupae differs but little from that of
the perfect insects/33' With the Coleoptera, the larvae likewise resemble
the perfect insects in this respect, — their mode of life being generally the
same, as has already been evinced by the structure of their oral organs.
The stomach is usually shorter and larger, and the number of its appendages
less, than with the perfect forms/34'

The larvae of the remaining holometabolic Insecta, which differ essentially
from the imagines as to their oral organs, beside living upon different food,
have also a digestive canal so different, that it must undergo a constant
and gradual change during the quiescent pupa state/355 Most of these larvae
have powerful masticatory organs, — such are those of the Lepidoptera, the
Tenthredinidae, the Siricidae, Phryganidae, Sialidae, and the cephalous
ones of the Culicidae and Tipulidae. The digestive canal here is straight
and rarely longer than the body ; its greater portion consists of a large and
usually varicose stomach, while the ileum and colon are pretty short. With
the larvae of the Lepidoptera, the cylindrical ileum is large and divided
into six lateral pouches, by as many longitudinal septa/30' But with the
cephalous larvae of the Mycetophilidae and Sciaridae, and the acephalous
ones of the Diptera, the digestive canal is formed upon a wholly different

31 This caecum is found with Hipparchia , Pon-
tia , Sphinx , Gastropacha , Euprepia , Acidalia ,
Cafrera, Adela, Chilo , and Tinea. It is wanting
with Vanessa , Zygaena, Hepiolus , Cossus , Ypo-
nomeuta , and Pterophorus.

32 See Nitzsch , in Germar's Magaz. d. Entom.
III. p.280 (Nirmidae); Nicolet , loc. cit. p. 46,
PI. IV. fig. 2 (Poduridae) ; Swammerdamm , Bib.
der Nat. p. 33, Taf. II. fig. 3 ; Ramdohr , loc. cit. p.
185, Taf. XVI. fig. 3, and Taf. XXV. fig. 4, and
Treviranus, Verm. Schrift. II. p. 13, Taf. III. fig.
1-6 ( Pedicuius and Lepisma).

33 See Suckow , in Heusinger\s Zeitsch. II. Taf.
I. fig. 8 ( Aeschna ), and Rathkc, in Miiller\ 8
Arch. 1844, p. 35, Taf. II. fig. 4 ( Gryllotalpa ).

34 With the larvae of Calosoma , the stomach is
straight and without caeca ( Burmeister , Trans, of
the Entom. Soc. I. p. 236, PI. XXIV. fig. 10, 11).

With Hydrophilus piceus, and Dytiscus mar-
ginalise it is varicose, slightly tortuous, and with-
out caeca ( Suckow , in Heusinger's Zeitsch. II.
Taf. IV. fig. 26, and Burmeister , Handb. I. Taf.
X. fig. 3). The larvae of the Latnpyridae, Pyrochro-
idae, Mordellidae, and Curculionidae, differ but
little from the imagines as to their digestive canal
(L. Du four, Ann. d. Sc. Nat. III. 1824, PI. XI. fig.
7 (Lampyris) ; Ibid. XIII. 1840, PI. V. fig. 5
( Pyrochroa ) ; XIV. 1840, PI. XI. fig. 9 ( Mor -
della ); and Burmeister , Zur Naturg. d. Calandra,
p. 8, fig. 3.) The most marked difference between
the larvae and the imagines, is observed with the
Lamellicornes. The first have a very spacious,

straight stomach, which, at both extremities and
sometimes also in the middle, has a circle of simple
or varicose, thickly-set caeca ; the ileum is very
short, and the large intestine extremely large and
always bent forwards *, see Roesel , Insektenbelust.
II. Taf. VIII. IX.; Suckow , loc. cit. III. Taf. III.
fig. 87 ( Melolontha ) f L. Dufour, Ann. d. Sc.
Nat. XVIII. 1842, PI. IV. fig. 8, PI. V. fig. 18
( Cetonia and Dorcus) ; finally, the excellent work
of De Haan , Sur les metamorphoses des Coleop-
t(h*es, Mem. I. les Lamellicornes, in the Nouv. Ann.
du Mus. IV. 1835, p. 153, PI. XVI.-XIX.

35 For this metamorphosis of the intestinal canal,
see Dutrochet, Jour, de Physique, &c., LXXXVI.
1818, p. 130, or MeckePs deutsch. Archiv IV. p.
285, Taf. III. ( Bombyx , Myrmeleon , Apis , Polis -
tes, Tenthredo and Eristalis). This metamor-
phosis with Sarcophaga haemorrhoidalis has
been described and figured by L. Dufour , M^m.
presents, &c., IX. p. 580, PI. III.

36 See Swammerdamm , Bib. der Nat. Taf.
XXXIV. fig. 4 Lyonet , Traite, &c., PI. XIII. ;
Ramdohr , loc. cit. Taf. XVIII. fig. 5. Many
naturalists have carefully observed the metamor-
phoses of the digestive canal with the Lepidoptera;
see Her old, Entwickelungsgeschichte d. Sehmetterl.
Taf. III. fig. 1-12 ( Pontia brassicae) ; Suckow,
Anat. physiol. Untersuch. p. 24, Taf. II. fig. 1-10
{Gastropacha pini) ; ami Newport, Philos. Trans.
1834, PI. XIV. fig. 11-13 {Sphinx ligustri).
This last author has figured the digestive canal in
situ in all the three states.

428

THE INSECTA.

§ 339.

plan. It exceeds more or less the length of the body, and there is a crop
at the posterior extremity of the oesophagus upon which succeeds a long
and tortuous stomach. Upon the cardiac portion of this last there are
inserted two to four caeca directed either forwards or backwards, and with
some larvae of the Muscidae, there is also a long, sucking stomach upon
one of the sides of the oesophagus. (37)

With the larvae of the Neuroptera, which suck up their liquid food through
tubular mandibles, the posterior extremity of the oesophagus is dilated into
a- pyriform sucking stomach, which is followed by the proper stomach,
large, of median length, and slightly flexuous. The extremely small ileum
is long and makes several convolutions, while the colon is large, vesiculi-
form, and continuous into a horny tubular rectum. (S8)

§ 339.

As to the gvandular appendages of the digestive canal of the Insecta,
the Salivary Organs are quite widely distributed, as well with the Imagines
as with the Larvae and feeding Pupae. These organs consist of one, or
two, rarely three pairs of colorless tubes of unequal length. These are
sometimes prolonged into the thorax, while in other cases they accompany
the digestive canal into the abdominal cavity where it makes many convo-
lutions. Their excretory ducts are composed of a solid membrane, and are
distinctly separated from the glandular portion.® This last is composed
of three layers, namely: an external, homogeneous envelope, — an intimate
tunic accompanying the excretory duct, — and a middle layer composed of
colorless, glandular, nucleated cells, which often form very fine excretory
tubes opening into the common duct. Frequently, also, these ducts contain
a spiral filament like the tracheae ; they open, each, at the base of the oral
cavity by a distinct orifice, and it is rare (2> that they unite, forming a
common duct ; sometimes they have, near their excretory openings, special
salivary reservoirs.® With very many Aptera,® Diptera, Lepidoptera,
and Coleoptera,® the salivary organs consist of two simple tubes, which,
with the larvae of the second and third of these orders, often extend a con-
siderable way into the abdominal cavity.® With the Cerambycidae, Te-

37 See S wammerdamm, Bib. der Nat. Taf. XLI.
fig. 6, Tab. XLIII. fig. 5 (Strut iomys and Pio-
phila,)} Ramdohr , loc. cit. Taf. XIX. fig. 1
(Musca) L. Dufoar , Arm. d. Sc. Nat. XI. 1839,
p. 212, PI. V. fig. 23, XII. p. 13, 18, PI. I. fig. 1,
4, and I. 1844, p. 372, PI. XVI. fig. 8 (< Ceroplatus ,
Sapromyza , Piophila).

The metamorphosis of this digestive canal, in
rhe pupa of Sarcophaga carnaria , is represented
in a suite of figures published by Suckow , in
Heusinger's Zeitsch. III. Taf. IX. fig. 147-153.
But Suckow has fallen into the same error as
Ramdohr (loc. cit. p. 171) in regarding the caecal
appendages of the stomach of the larvae as four
tubes connecting the stomach with the salivary
canals.

•38 See Ramdohr , loc. cit. p. 154, Taf. XVII. fig.
1 ; and L. Dufour , Recherch. &c. p. 589, PI. XII.
fig. 175 ( Myrmeleon ). The large intestine together
with the rectum, does not serve, with this larva, as
a defecating organ, but, as is very extraordinary,
has the function of a Spinneret (see § 347).

1 For the intimate structure of these organs, see
//. Meckel , in Muller's Arch. 1846, p. 25, Taf. I.
II.

2 Piophila , Musca , Sarcophaga , Tabanus ,
Hippobosca , Oestrus , Mordella , Mantis , and
Forjicula.

3 With Forjicula , Musca, Sarcophaga, and
Hippobosca, each of these excretory ducts is dilated
into a roundish reservoir 5 but with the Termitidae,
Acrididae, Achetidae, and Mantidae, there is an
oblong, pedunculated reservoir common to both
ducts. See, for the figures, the various memoirs of
L. Dufour.

4 With the Nirmidae.

5 Pyrochroa, Lixus , Phyllobius, Diaperis ,
Lema, Oedemera, Chrysomela, Coccinella. In
this last genus, the two salivary vessels are to-
rose.

6 See the figures in the works of S wammerdamm ,
Lyonet , Ramdohr , Suckow, Her old , and L. Du-
four.

§ 339.

THE INSECTA.

429

nebrionidae, Mordellidae,*7* and most of the Hymenoptera,® they consist
of two rather short, ramified tufts, often contained entirely in the head.®
Among the Neuroptera, the Myrmeleonidae and Sialidao have two simple
short salivary tubes, while, with the Phryganidae and Hemerobidae, they
are ramified and highly developed. (10) It is quite remarkable that there is,
in this respect, a sexual difference with the Panorpidae ; the males have
three pairs of very long, tortuous tubes, while, with the females, the only
vestiges of this apparatus are two indistinct vesicles. (11) Among the Or-
thoptera, the salivary organs are entirely absent with the Libellulidae, and
Kpherneridae. On the other hand, they are highly developed with the
Achetidae, Acrididae, Locustidae, Mantidae, Blattidae, Termitidae, and
Perlidae, where they consist of two, four, or six botryoidal masses of
vesicles, situated in the thorax, and having long, excretory ducts, beside,
also, often long-pedunculated pyriform reservoirs/12* Among the Hemi-
ptera/13* these organs are absent with the Aphididae and the Psyllidae ; but,
on the other hand, they are very large and of a remarkable structure with
the "Bugs and Oicadidae. Here they are nearly always lobulated, and are di-
vided by a constriction into two portions, of which the upper is much smaller
than the lower, and often both have long digitiform processes. The excretory
duct divides, immediately after its origin, into two special canals of equal
or very unequal length, which extend, serpentinely, first, into the abdom-
inal cavity, and then ascend to the mouth/14* Beside these two constricted
glands, many Bugs have, also, one, rarely two pairs of simple salivary
tubes, <l5> which are often dilated, vesiculiform, at their extremity/16* The
salivary organs of the musical Oicadidae differ in many respects from those
of the others of this family ; for, beside the two simple tortuous tubes, there
is, in the head, another pair of glands, composed, each, of two tufts of short,
cylindrical caeca, situated one behind the other.117* It is yet undetermined

7 See Z. Du four, Ann. cl. Sc. Nat. IV. 1824, PI.
XXIX. fig. 4, 5, XIV. 1840, PI. XI. fig. 16.

8 See L. Du four, Recherch. &c. p. 390, fig. 48,
72, 109, 148 ( Apis , Andrena , Philanthus, and
Xyphidria.

9 With the Coleoptera, the ramified glands end
in long, tortuous caeca ; while with the llymenop-
tera, their extremities are vesiculiform, thereby
giving the whole gland a botryoidal aspect.

1° See L. Du four, Recherch. &c. p. 563, fig.
179,184,191, 192, 208,209 (Myrmeleon, Sialis,
Hemerobius, and Phryganea).

11 See Brants , Tijdschr. voor naturl. Geschid.
en Physiologie, 1839, p. 173 ; and L. Dufour,
Recherch. &c. p. 582, fig. 169 ( Panorpa ).

12 See L. Dufour, Recherch. &c. p. 296, PI. I.-
V. XIII. (Tridactylus, Oedipoda , Gryllotalpa,
Ephippigera, Mantis, Blatta, Ternies , and
Per la).*

13 For the salivary organs of the Hemiptera, see,
beside Ramdohr, loc. cit. Taf. XXII. XXIII.
especially L. Dufour, Recherch. sur les Herni-
pt^res, p. 118, PI. I.-IX-

14 The two excretory ducts are of the same length

* [ § 339, note 12.] See also Leidy, loc. cit. p.
82 ( Spectrum femoratum). — Ed.

t [ § 339, note 14.] With Belostoma, the
salivary glands are four in number, are of con-
glomerate structure and situated on each side of
the oesophagus into the commencement of which
they empty. Two of them are long and extend
backwards as far as the commencement of the ab-

with Ranatra, Nepa, Naucoris, Corixa, Redu-
vius, and Syrtis. One is very long and the other
very short with Tetyra, Pentatoma, Syromastes,
Coreus , Lygaeus, Aphrophora and Cercopis.
With the liydrocorisae, above cited, the two sali-
vary glands are, moreover, composed of numerous
round secretory vesicles. In general, these glands
have been regarded as composed of two vesicles
each of which has a proper excretory duct •, but
this view is incorrect. The two excretory ducts
are always the result of the division of a common
trunk which arises at the constricted point of the
gland. With Ranatra , alone, the anterior is en-
tirely separated from the posterior portion of the
gland, f

15 There is only one pair of simple salivary glands
with Tetyra, Pentatoma , Pyrrhocoris, Lygaeus,
Naucoris , Nepa and Ranatra ; two pairs with
Coreus and Alydus. With Nepa and Ranatra,
they dilate into an oval reservoir.

16 Syrtis , Rcduvius, Pe/egonus, and Corixa.

17 See L. Dufour, Ann. d. Sc. Nat. V. 1825, p.
158, PI. IV. and Recherch. &c. PI. VIII.

domen *, while the other two are about one-fourth
as long. Beside these, on each side of the oesoph-
agus, there is situated a sigmoid caecal pduch
which opens by a narrow duct into the commence-
ment of the oesophagus in the vicinity of the termi-
nation of the salivary ducts ; these are perhaps
reservoirs of the saliva •, see Leidy, loc. cit. p. 63.
— Ed.

4 00 THE INSECTA. § 8S9.

whether one of the pairs of these glands with these Hemiptera, may not be
a poison apparatus.

The Insecta have no distinct Hepatic Organs, but the function of a Liver
is performed by the walls of the stomach, the internal tunic of which is
composed of closely-aggregated hepatic cells. With many species whose
stomach has caecal appendages, the walls of these last have a similar hepatic
structure, and must secrete, therefore, a bile-like fluid. <18)

With some Insecta, the ileum has glandular appendages, whose product
is perhaps analogous to a pancreatic fluid. The two or four rows of fol-
licles which, as before mentioned, are situated on the ileum of the Penta-
tomidae and some Coreidae, would, in the same manner, be regarded as a
Pancreas. The same remark applies to the ramified appendages, which,
with Gryllotalpa, open into the stomach below the two caeca, as well, also, as
to the two or three follicles which, with Pyrrhocoris , are inserted, laterally,
on the posterior part of the ileum. (19)

There is found, with all Insecta, a Corpus adiposum , — a tissue, composed
of adipose cells, which is intimately connected with the functions of digestion
and assimilation. This body is especially developed towards the end of
the larval state, and it disappears, for the most part, during the pupa
period, so that only a few traces of it are found with Insecta in their per-
fect state. It is usually of a white, or a dirty-yellow color, but is also
observed of a green, red, or orange hue. In the larvae, the fat cells gen-
erally form pretty large, lamelliform lobes, sometimes ramified or reticu-
lated, sometimes plicated, spread through the abdominal cavity in all the
intervals of the viscera. These lobes are always traversed and retained
in place by numerous trachean branches. With the perfect Insecta, the
remains of this body are not usually found except in the posterior portion
of the abdominal cavity, where they consist of fat-cells loosely scattered,
and not retained by the tracheae. (20>

19 For these biliary organs, see J. Muller , De
Gland, struct, p. 67. The Malpighian vessels
which were formerly regarded as biliary tubes,
will be treated of in future (§ 346).*

19 See L. Dufour , Recherch. sur les Orthopt. p.

332, PI. II. fig. 19 ( Gryllotalpa ), and Recherch.

* [ § 339, note 18.] The liver of the Insecta, as
well as that of the Invertebrata generally, has been
investigated by Will ( Muller's Arch. 1848, p. 502)
who has applied the same chemical mode of in-
quiry, as that of Brugnatelli and Wurzer upon
the Malpighian vessels showing their urinary char-
acter (see infra § 345, note 2). With the Insecta,
he regards as hepatic the caecal and other glandu-
lar appendages which, when present, lie upon the
so-called Ventriculus , thus confirming the suppo-
sition expressed in the foregoing note. For the in-
timate microscopic structure of the liver of the In-
secta, see Leidy , Amer. Jour. Med. Sc. XV. 1848,
p. 1. — Ed.

f f § 339, note 19.] For the hepatic organs of
Belustoma , see Leidy , loc. cit. p. 63, PI. X. fig.

4, i. They consist of four long very tortuous tubes

sur les Il£mipt£res, p. 44, PI. II. fig. 19, 21 ( Pyr-
rhocoris).f

20 See L. Dufour , Recherch. sur les Carabiq.,in
the Ann. d. Sc. Nat. VIII. 1826, p. 29 ; Recherch.
sur les Hemipt. p. 141, and Recherch. sur lea
Orthopt. p. 291, 385, 562.j:

closely applied to the intestinum tenue *, they join
the intestine at the junction of the duodenum and
ileum. — Ed.

\ [ § 339, note 20.] See, upon the Corpus adi-
posuin , Mayer (Ueber die Entwickelung. des Fet-
tkorpers, &c. bei den Lepidopteren, in Siebold
and Kolliker's Zeitsch. I. p. 175) who has traced
its development.

These adipose bodies are formed from a great
number of separate, flattened, usually many-
pointed lobes. These lobes consist of pouches with
structureless walls, and filled with fat-globules.
Each pouch is originally a simple cell with a large
nucleus attached to its wall. In this cell are
formed daughter-cells, which, when filled with fat,
burst, and thereby the mother-cell becomes the fat-
containing sac. — Ed.

$ 340.

THE INSECTA.

431

CHAPTER VI.

CIRCULATORY ORGANS.

§ 340.

The Circulatory System is feebly developed with Insecta, consisting of a
contractile, articulated Vas dorsale, and a cephalic Aorta. The first serves
as a heart, and the second is a simple conductor of the blood from the heart
into the body. In both of these vessels, the blood moves from behind forwards,
and, at its escape from the aorta, traverses the body in all directions, forming
regular currents which have, however, no vascular walls. In this way, it
penetrates the antennae, the extremities, the wings, and the other appendages
of the body, by arterial currents, and is returned by those of a venous
nature. All the venous currents empty into two lateral ones running
towards the posterior extremity of the body, and which enter, through lat-
eral orifices, the dorsal vessel/1’

1 Swammerdamm , Malpighi , and others of the
older anatomists, had already formed a pretty exact
idea of the circulation of the Insecta. But, subse-
quently, it was entirely abandoned when it was ob-
served that the dorsal vessel was a closed tube, and
served only as a simple reservoir of the nutritive
juices. Cams was the first to demonstrate anew
the existence of a circulation which has since been
confirmed with all the three stages of insects. See
Carus, Entdeck. eines einfachen, vom Herzen aus
beschleunigt. Blutkreisl. in den Larven netzfliiglich.

Insekt. 1827 *, Nov. Act. Acad. Nat. Cur. XY.
part II. p. 8, Taf. LI. •, and Lehrb. d. vergleich.

Zoot. 1834, p. 687 \ R. Wagner , Isis, 1832, p. 320,

778 ; Burmeister , Handb. &c. I. p. 164, 436 ;

Bowerbank , Entom. Mag. 1. 1833, p. 239, IV. 1835,
p. 179 (also in Froriep's ueue Notiz. XXXIX. p.

149) ; Tyrrell , Philosoph. Trans. 1835, p. 317
Newport , Cyclop. &c. II. p. 980 ; Milne Ed-
wards, Ann. d. Sc. Nat. III. 1845, p. 278 ; and
Quatrefagcs , Instit. 1845, p. 305. This circula-
tion carried on by the dorsal vessel, having been
observed by so many distinguished naturalists, it is
truly incomprehensible that L. Dufour (Recherch.
sur les Hemipt. p. 272 \ Recherch. sur les Orthopt.
p. 287 5 Ann. d. Sc. Nat. XVI. 1841, p. 10 ; Mem.
presentes d I’Inst. IX. p. 595, 601) can persist in
denying that the dorsal vessel is anything but a
secretory organ which, according to him, has no
opening and therefore nothing in common with a
heart. lie cites the authority of Cuvier who was
unwilling to accord to the Vas dorsale either the
name or the functions of a heart ( Cuvier , Mem.
sur lamaniere dont se fait la nutrition dans les In-
secte3, in the Mem. d. 1. Soc. d’Hist. Nat. de Paris,

VII. 1798, p. 34, or Reil's Arch. V. p. 97). L.

Dufour adduces, moreover, in support of his erro-
neous view, the following remark of Carus (Erlflu-

* f § 340, note 1] The results obtained by
Blanchard have been very satisfactorily confirmed
by Agassiz (Proceed. Amer. Assoc. Advancera. Sc.

1849, p. 140, also its translation into French in the
Ann. d. Sc. Nat. 1851, XV. p. 353), who has suc-
ceeded in distinctly injecting the tracheae by the
dorsal vessel. These experiments I have had the

terungst. lift. VI. p. 8), “ In the perfect Insecta,
whose respiration is performed by a system of
tracheae traversing the entire body, the circulation
of blood would be useless.” But to this it may be
replied, that Carus , by these words, has contra-
dicted his proper observations } for he has shown
that there is a circulation in many perfect insects,
as is stated not only in the Nov. Act. Nat. Cur., loc.
cit., but also in the Erlduterungstafeln from which
the above citation was taken. At all events, the
proposition of Carus is correct, u that in insects, the
blood must come in contact with the atmospheric
air, which is accomplished by means of the tra-
chean system.” But this applies only to the small
portion of the circulation connected with the respi-
ratory process ; whereas, the larger portion, des-
tined for the general nutrition of the tissues, does
not evidently require the presence of tracheae. The
presence of a real blood-circulation by means of the
Vas dorsale , is so easily observed, that the injec-
tions of Blanchard are scarcely necessary (Compt.
rend. XXIV. 1847, p. 870).

If, in certain species, although transparent, these
phenomena are not observable, we must not be too
hasty in denying its real existence, for the blood,
which is not visible except through its globules, is
often so poor in these last, as to elude our observa-
tion. Verloren has recently given a very com-
plete r£sum4 of what has been done on this sub-
ject, and has added new and confirmatory observa-
tions •, see Hollandische Beitr. zu den anat. und.
physiol. Wissenschaft. I. lift. 2, p. 220 •, and M£-
moire en response d la question suivante : dclaircir
par des observations nouvelles le phenomdne de la
circulation dans les Insectes, en recherchant si peut
la reconnaitre dans les larves des differents ordres
de ces animaux, in the Mem. couronn. par l’Acad.
de Belgique, XIX. 1347.*

good fortune to witness, and their character was
such as to leave with me no doubt as to the peri-
trachean circulation. See, also, the additional evi-
dence which Blanchard (Compt. rend. Oct, 6,
1851) has recently furnished of a peritf’achean cir-
culation, which is very important and weighty.
He took advantage of the well-known fact that sil':;-

432

THE INSECTA.

§ 340.

The Blood of the Insecta is usually a colorless liquid, though sometimes
yellowish, but rarely red.(2> In this liquid are suspended a few very small,
ov/il, or spheroidal corpuscles, which are always colorless, have a granular
aspect, and are sometimes nucleated.'3’

The Dorsal Vessel, which is constricted at regular intervals, is always
situated on the median line of the abdomen, being attached to the dorsal
wall of its segments by several triangular muscles whose apices point out-
wards. Its walls contain both longitudinal and transverse fibres, and,
externally, are covered by a thin peritoneal tunic. Internally, it is lined
by another very fine membrane, which, at the points of these constrictions,
forms valvular folds, so that the organ is divided into as many chambers as
there are constrictions. Each of these chambers has, at the anterior
extremity on each side, a valvular orifice which can be inwardly closed.'4’
The returning blood is accumulated about the heart and enters into it
during the diastole of each of its chambers, through the lateral orifices.®
It then passes, by the regularly successive contractions of the heart, from
behind forwards into the aorta which is only a prolongation of the anterior
chamber. This aorta consists of a simple, small vessel, situated on the
dorsal surface of the thorax, and extending even to the cephalic ganglion,,
where it either ends in an open extremity, or divides into several short
branches which terminate in a like manner.® The length of the dorsal
vessel depends, in all the three states of insects, upon that of the abdomen.
The number of its chambers is very variable, but is, most usually, eight.'7’
The blood, after leaving the aorta, traverses the body in currents whici}

2 The blood is red in many larvae of Chirono-
mus.

3 For the blood of Insecta, see Wagner , Zur ver-
glpich. Physiol, d. Blutes, lift. 1, p. 26, lift. 2, p.
3!*, and Isis, 1832, p. 323 ; Horn , Das Leben d.
Blutes, p. 9, Taf. I. and Newport , Institut. 1845,
p. 241, or Ann. d. Sc. Nat. III. 1845, p. 364, or
Froriep's neue Notiz. XXXIV. p. 9.

4 For the structure of the dorsal vessel, see
Straus , Consid. &c. p. 356, PI. VIII. (. Melolon -
tha vulgaris) ; Wagner , Isis, 1832, loc. cit. Taf.
II. (larvae of Diptera and Ephemeridae), and in
Muller's Arch. 1835, p. 311, Taf. V. (larva of
Corethra plumicornis) ; Newport , Philos. Trans.
1843, p. 272, and Cyclop, loc. cit. p. 976, fig. 433,
A. and 434 ( Lucanus cervus and Asilus crabri-
formis) ; finally Verloren, Mem. loc. cit. p. 31,
PI. II I. -VII. ( Chironomus , Sphinx , Rhyncho-
phorus , Pompilus , Syrphus , and Vespa). The

worms fed on different artificially-colored leaves
produced correspondingly colored cocoons. He
therefore fed, in the same manner, various larvae,
and, upon dissection, found not only their blood but
also their tracheae colored like the color used.
With the tracheae, this color was deepest at the
base, but gradually paled away towards their ex-
tremity. What adds a corroborating value to these
experiments is the fact that the muscles here re-
mained uncolored, thus showing that this special
trachean coloration was not due to a bathing of the
general fluids of the body. Compare also the re-
cent various notes and papers of Blanchard , in
Ann. d. Sc. Nat. — Ed.

* [ § 340, note 4.] See also, for histological de-

constrictions of the dorsal vessel are feebly marked
with the larvae of the Diptera and Ilymenoptera.*

5 According to Newport (Cyclop, loc. cit. p.
977), the space in which the blood accumulates
about the heart is surrounded by a very thin mem-
brane, and may therefore be regarded as a true
auricle.

0 The Aorta is divided at its extremity with
Melon, Blaps , Timarch a, Vanessa, and Sphinx ;
see Newport , Cyclop, loc. cit. p. 978.

7 With the Orthoptera, Lepidoptera, and their
larvae, as also with various larvae of Diptera. It
is rare that the number of chambers exceeds eight,
as, for example, with the Poduridae (. Nicolet , loc.
cit. p. 50, PI. IV. fig. 3). More commonly there
are seven, as with Lucanus and Dytiscus ( New-
port, Cyclop, loc. cit. tig. 433, A., and Wagner ,
Icon. Zoot. Taf. XXII l. lig. 2). Burmeister
(Handb. I. p. 165) has observed only four with the
larva of a Calosorna.

tails upon the heart, Ley dig , Siebold and Kol-
lilcer's Zeitsch. 1852, III. p. 446 (larva of Co-
rethra plumicornis). This naturalist has here
described a new and peculiar kind of valves, which
deserve particular notice. In the last chamber of
the heart, there are six or eight pairs of roundislL,
clear bpdies, attached to the inner surface of the
heart by a peduncle. They alternate in their posi-
tion, one beyond the other, so that, during the sys-
tole, two of them are so opposed that the calibre of
the chamber is completely closed at that point.
Each of these curious valves is only a pedunculated
nucleated cell j see loc. cit. Taf. XVI. fig. 2, c. —
Ed.

§ 341.

THE INSECTA.

433

are always extravascular, and in this way bathes all the organs.® The
newly-prepared nutritive fluid passes through the walls of the digestive
canal in which it is found, into the visceral cavity, and thence directly into
the blood. Latterly, this extravascular circulation has been called in ques-
tion, but its presence may be easily and directly observed with very many
perfect Insecta and their larvae. The vascular walls supposed to have
been seen at certain points, are, undoubtedly, the result of some error of
observation or interpretation.® This is also true of the pulsatile organs
supposed to have been observed in the legs of many water-bugs, and which
were thought to affect the circulation.8 * (10) * * 3

CHAPTER VII.

RESPIRATORY SYSTEM.

§ 341.

The Insecta respire, in all their conditions of life, by means of a system
of Tracheae which are spread through the entire body and penetrate all the
organs. This system of air-vessels either opens externally by stigmata
through which the atmospheric air is introduced directly, or they have no
external communication, but derive the air from the water by means of
lamellifonn or tubular prolongations with which the tracheae terminate,
and which have often been compared to branchiae. (,) In the first case, they
are called Pulmonary tracheae, and in the second, Branchial tracheae.

8 In the antennae, the legs, the filaments of the
tail, and other appendages, the arterial and ven-
ous currents are contiguous. But in the wings
they are are isolated ; and although they may be
observed in the nervures of the wings, yet these
last should not therefore be regarded as true blood-
vessels, for their cavities are only prolongations of
the visceral cavity, as is shown by the fact that
they are sometimes traversed at the same time by

branches of tracheae. In the memoir of Verloren
(loc. cit. p. 76) will be found a very complete ac-

count of all the reasons opposing the presence of

vascular walls in Insecta.

0 The same should probably be said about the
thin walls which Bowerbank , and Newport (loc.
cit.) think they have observed with Ephemera
concerning the two lateral currents which run to-
wards the posterior extremity of the abdomen.
Another vessel which, according to Treviranus
(Zeitsch. f. Physiol. IV. p. 182, Taf. XIV. fig. 13)
and Newport (Philos. Trans. 1834, p. 395, PI. XIV.
fig. 9, and Cyclop, loc. cit. p. 980), is found in the
larvae and imagines of Lepidoptera above the
ganglionic chain, and is the analogue of the supra-
spiral artery of the Myriapoda (§ 284), requires
further research, for it may be questioned if such
an organ, found only in certain groups of Insecta,

i3 really a vessel.

10 Very dissimilar and contradictory opinions
have been published on these pulsatory organs.
Behn (. Muller's Arch. 1835, p. 554, Taf. XIII. fig.
13, 14, or Ann. d. Sc. Nat. IV. 1835, p. 5) has de-
scribed them with Corixa , Ploa, Naucoris , Nepa ,
and Ranatra , as thin, movable lamellae attached
to the inner wall of the tibiae. Verloren (Mt*m.
loc. cit. p. 82, PI. VI. fig. 24, 25) has confirmed
these observations with the Cicadidae, although
neither L. Du four (Ann. d. Sc. Nat. IV. 1835,
p. 313) nor Wesmael (Bullet, de PAcad. de
Bruxell. III. p. 158) has been able to discover
them in the water-bugs above cited. It is possible
that these apparent pulsations are produced simply
by the contractions of neighboring muscular fibres.

1 See Burmeister (Handb. &c. I. p. 179 *, Let-
cordaire , Introduct. &c. II. p. 89 ; and Newport ,
Cyclop, loc. cit. p. 983). These organs have not the
structure of true branchiae, and the blood is not
subjected in their interior to the respiratory act, as
is shown by the small quantity of this fluid which
traverses them. These false branchiae are evi-
dently designed to receive air, or, to speak more
properly, to act, through endosmosis and exosmosis,
in the transference of air from the water into the
tracheaen system. Dug 4s (Traite de Physiol. IL
p. 549) is therefore correct in terming them Bran-
chies trachtales.

37

434

THE INSECTA.

§ 342.

The tracheae are cylindrical tubes of variable size, which often form, in
their course, vesicular dilatations and numerous anastomoses. They divide,
like blood-vessels, into many branches which gradually decrease in size,
ending, at last, caecally, so that the expired air passes out by the same way
that it entered.

The intimate structure of these organs is remarkable, and has always
attracted the attention of anatomists. <2) When filled with air they present
a beautiful, silver appearance. Externally, they are invested with a thin
transparent, colorless, or very rarely brownish membrane, corresponding
to a peritoneal envelope.® Internally, they are lined with another mem-
brane still finer, which presents a lamellated epithelial structure.® Between
these two membranes is situated a solid spiral filament whose turns are
usually near together. This filament is sometimes cylindrical, sometimes
flattened, usually transparent and colorless, and in a few instances only,
of a dark color.® Often, its course is unbroken for a long distance, and
rarely is its extremity forked. The new threads always begin between the
turns of the preceding one, as may be easily observed at the commence-
ment of each trachean ramification. In the ultimate trachean branches,
these threads gradually decrease in size, and at last become indistinct. In
the vesicular dilatations of the tracheae, with many Insecta, the spiral thread
is oft6n wholly wanting.® *

§ 342.

The Branchial tracheae are found only in certain aquatic larvae and
pupae, and never in the perfect Insecta. The absence of stigmata here is
compensated by the existence of false branchiae ( Branchiae spuriae seu
tracheales), which are cylindrical, or riband-like organs covered by a very

2 For the internal structure of the tracheae, see, be-
side the works of Burmcister , Lacordaire , and
Newport , that of C. Sprengel , Comment, de partib.
quibus Insect, spiritus ducunt, 1815 *, Suckow , in
Heusinger's Zeitsch. II. p. 24, Taf. I. fig. 10 *,
Straus , Consid. &c. p. 315, FI. VI. fig. 5 ; New-
port, Philos. Trans. 1836, p. 529 ; and Plainer , in
Muller's Arch. 1844, p. 38, Taf. III.

3 This membrane is brown in the Libellulidae
and Locustidae ; this coloration is due to a finely-
granular substance contained in the membrane.

4 See Plainer, loc. cit. Most anatomists regard
this internal membrane as mucous. This being ad-
mitted, it was very natural to suppose that it, like
that of the lungs of the Vertebrata, is covered with
cilia. But here, as well as in other regions of the

* [ § 341, end.] See, also, for investigations upon
the intimate structure of the tracheae, Dujardin
(Comp. rend. 1849, p. 674), and Mayer (Ueber die
Entwickelung. des Fettkorpers, der Tracheen, &c.
&c., bei den Lepidopteren, in Siebold and Kolli-
ker's Zeitsch. I. p. 175). The views of Dujardin
are different from those usually received, for he
regards the spiral thread not as a special forma-
tion, but only a fold-like thickening of the internal
membrane, — which membrane is not composed of
cells but is a structure analogous to the wing-mem-
brane, and is covered with hair3 and points. On

body of insects, there is no trace of ciliated epi-
thelium, which, indeed, would be incompatible
with the presence of chitine. Peters ( Muller's
Arch. 1841, p. 233) was certainly deceived when he
thought he observed ciliary movements in the
tracheae of Lampyris, Coccinella , Mu.sca, and
other Insecta. lie has himself admitted that
he was not able to distinguish the cilia. For my
part, I have sought in vain for this- movement in
the tracheae, and Stein (Vergleich. Anat. u. Phys-
iol. d. Insekt. 1847, p. 105) has been equally un-
successful.

•r> The tracheae of the larvae of the Dytiscidae owe
their black color to the spiral filaments.

6 With the Muscidae, Syrphidae, Vespidae, Api-
dae, and Melolonthidae.

the other hand, Mayer, who has studied the embry-
onic development of these organs, states that the
spiral thread is originally a homogeneous mem-
brane, which ultimately splits up into the threads.

This subject of the structure of tracheae has now
an additional point of interest, from its relations to
Blanchard's views of a peritrachean circulation in
the Insecta. In this connection see especially Fi-
lippi (Annali della R. Accad. d’agricolturo di
Torino. V., also fViegmann's Arch. 1851, Th. II.
p. 145). — Ed.

§ 342.

THE INSECTA.

435

thin cutaneous membrane, and containing one or several finely-divided
trachean trunks. These trachean branchiae are either isolated, or fasci-
culated ; in this last case, they are often digitiform, or penniform, and their
ultimate ramifications are usually deficient in the spiral filament. All the
air-vessels which these branchiae contain, arise from the larger trachean
trunks. These branchiae occur with various Tipulidae, with a Nymphula ,
with the Phryganidae, Sialidae, Ephemeridae, Perlidae, Libellulidae, and
with the Gyrinidae.

This trachean system is most simple with the larvae of Tipulidae of the
genera Chironomus, Tanypus, Corethra and Simidia, as also with some
larvae of the Phryganidae, of the genera Rhyacophila and Hydropsyche,
where the tracheae, instead of forming cutaneous appendages, are sub-
cutaneous and can therefore extract air from the water. The larvae of Core-
thra are distinguished for having in the thorax and abdomen, directly
beneath the skin, two adjacent trachean vesicles, by means of which, very
probably, the necessary renewal of air takes placed1 2 3 4 5' With the pupae of
Simulia, there are two branchial tufts on the sides of the prothorax, com-
posed, each, of six to eight long caecal tubes, which contain' each a single
simple trachea deficient in the spiral thread.® Of the various larvae of the
Lepidoptera, living under the water, that of Nymphula stratiotalis , alone,
has trachean branchiae. These consist of fasciculate filaments situated on
the sides of the abdominal segments.® With the larvae of Sialis, each of
the six, seven or eight abdominal segments has upon its sides an articulated,
filiform thread, containing a trachean vessel, and which may, therefore, be
regarded as a trachean branchia.® Most of the larvae and pupae of the
Phryganidae, have, at the same points, one or two filiform, trachean
branchiae, rarely ramified, and united in groups of from two to five, which
stand out towards the back.® With those of the Ephemeridae, each of
the anterior abdominal segments has a pair of these branchiae which are
sometimes ramified in the most varied manner, and sometimes consist of
two kinds, some being lamelliform and alternating with the others which
are fasciculate.® With all the Ephemeridae, these organs have move-
ments which are sometimes slow and rhythmical, and sometimes rapid and
oscillatory.

With the Perlidae, the branchiae are filiform, ramified, and situated on
the three thoracic segments of the larvae and pupae, or bound together in
several short fasciculi which cover the base of the legs.®

Among the Libellulidae, the larvae and pupae of Agrion and Calo-

1 See Reaumur, Mem. toe. cit. V. PI. VI. fig. 7,
or Lyonet, Mem. du Mus. XIX. PI. IX. fig. 14,

15.

2 See Verdat and Fries , in T lion's Entom.
Arch. II. p. 66, 69, Taf. III. One must be careful,
and not confound, as has sometimes occurred, the
hairy tufts of these larvae for the tufts of tracheae.

3 See Degeer , Abhandl. I. Abth. III. p. 85,
Taf. XXXVII. fig. 5, 6.

4 See Rocsel, Insektcnbelust. II. Insecta aquat.
Class. II. Taf. XXIII.-, Degeer, Abhandl. II.
Taf. XXIII. j Suckow , in Hcusinger's Zeitsch.
II. Taf. III. tig. 23, 24 and Pictet , Ann. d. Sc.
Nat. V. 1836, PI. III. During the passage into
the pupa state, which occurs with Sialis out of the
water, these tracheae are cast off.

5 See the figures of Pictet, ltecherch. pour servir
A Phist. et A Panat. d. Phryganides, PI. II. &c.;
and Deseer, Abhandl. II. Taf. XII. The bran-

chiae are ramose with Hydropsyche , and Rhya-
cophila.

6 See S wammerdamm , Bib. der Nat. Taf. XIII.-
XV. , Reaumur, Mem. VI. PI. XLII.-XLVI.; De-
geer, Abhandl. II. Taf. XVI.-XVIII.; Suckow ,
in II e using er's Zeitsch. II. Taf. III. fig. 21, 22;
Car us, Entdeck. eines Blutkreisl. loc. cit. Taf. III.;
and the figures of Pictet, Hist. d. Insect. NAvropt.
EphAmerines.

7 See the figures of Pictet, Ilist. d. Nevropt.,
Perlides. According to Newport (Ann. of Nat.
Hist. XIII. p. 21, or Froriep's neue Notiz. XXX.
p. 179, or Ann. d. Sc. Nat. I. 1844, p. 183),
these branchial tufts persist, with Pteronarcys
regalis, to the imago state. This would be a
very extraordinary anomaly, and should be con-
firmed, for, from the observations of Newport, it
does not appear that the tufts of hair situated on
the thorax of this Perlide really preserve the struc-
ture of branchial tufts.

436

THE INSECTA.

$ 343.

ptenyx are distinguished for having three long, lamelliform branchiae, with
a rounded extremity, and situated vertically upon the posterior part of the
abdomen.®

The trachean branchiae of Aeschna, Libellula, and the other Libellu-
lidae, are formed upon a wholly different plan. They are situated in the
very large rectum, and consist of numerous epithelial folds which are
traversed by a great number of very fine branches of many large trachean
trunks. The rectum is, moreover, invested by a very highly-developed
muscular tunic, and its orifice has three pyramidal valves which regulate
the entrance and the escape of the water required for respiration.®
Finally, the larvae of Gyrinus have a pair of long branchiae upon the
sides of each of the first 'seven abdominal segments, and two pairs on those
of the eight.8 9 (10)

§ 343.

The tracheae most universal with Insecta are those termed Pulmonary,
which are characterized by the presence of stigmata ( Spiracula ). These
last are round orifices or narrow two-lipped openings, situated at various
points on the external surface of the body, and which, with many soft-skinned
Insecta, are surrounded by a horny ring. Usually, their borders are fringed
with small, short, simple or pinnate hairs,® and can be opened and shut by
means of an internal muscular apparatus ; this last is sometimes attached
to two inwardly-projecting horny plates. By these means, many Insecta
have well-marked respiratory motions, especially of the abdomen.®

With the larvae of the Lamellicornes, the stigmata have a peculiar
organization. They are closed by a horny membrane whose semilunar
borders are cribriform for the free passage of air.®

The larvae of the Oestridae have two large stigmata, covered each by a
similar plate or membrane, at the extremity of the abdomen ; and with
some larvae of the Muscidae, the posterior stigmata are closed in the same
manner, excepting that the membrane is perforated by three very distinct
openings.

Each stigma is usually the entrance of only a single trachean trunk

8 Roesel , Insectenbelust. II. Insecta aquatica,
Class. II. Taf. IX. XI.} and Carus , Entdeck. &c.
Taf. I.

9 Roesel , loc. cit. Taf. III.-YIII. and Suckow ,
in Fie us Inzer's Zeitsch. II. p. 35, Taf. I. II.

10 Roesel , loc. cit. III. Taf. XXXI. and De-
geer , Abhandl. IV. Taf. XIII. Farther researches
are required to decide if the penniform appendages,
situated on the sides of the abdominal segments of
certain larvae of the Hydrophilidae, are really
trachean. branchiae. But it appears to me that,
with these larvae, the pulmonary and trachean
branchiae are confounded 5 see Roesel , Insecten-
belust. II. Insect, aquat. Class. I. Taf. IV. and
Lyonet, Mem. du Mus. XVIII. PI. XXIII. (12),
fig. 47 ( Hydrophilus caraboides.)

1 L. Dufour , Ann. d. Sc. Nat. VIIJ. 1826, p. 20,
PI. XXI.

2 The Locustidae, Libellulidae, and other Ortho-
ptera, make true movements of inspiration and ex-
piration, by alternately dilating and contracting
the abdominal segments. With the Apidae, Ves-
pidae, and other llymenoptera, the alternate con-
li-actions and dilatations of the abdominal cavity are

due to the protractile and retractile movements of
the abdominal segments. Many Lamellicornes
make these respiratory movements before flying,
probably that they may fill their trachean system
with air. r

3 Sprengel (loc. cit. p. 9, Tab. I.) has described
very correctly the stigmata of the Lamellicornes.
Treviranus (Die Erschein. und Gesetze d. Organ.
Lebens, I. p. 258) thinks that these lamellae are not
perforated and that the air enters these tracheae by
endosmose, although Burmeister (Handb. &c. I.
p. 172) says he has observed a single central open-
ing. £ have been unable to confirm the statement
of Sprengel , and think that these perforations
might easily elude the observation, from their being
concealed beneath a kind of net-work on the exter-
nal surface of these lamellae. L. Dufour (Ann.
d. Sc. Nat. XVIII. 1842, p. 173, PI. IV*. fig. 7) has
also misapprehended the stigmata of the larvae of
Cetonia ; for that which he has described as a
transverse fissure is only a fold, due to a pressure
exercised during the manipulation, on the horny
lamella which normally is convex and imperforate
in its centre.

§343.

THE INSECTA.

437

which ramifies more or less directly ; sometimes, however, several trunks
arise from the same stigma.®

With perfect Insecta, the stigmata are nearly always situated on the
sides of the body in the membrane connecting the two segments, being
always wTanting, however, in the membrane which unites the head and pro-
thorax, and that between the last two abdominal segments. In many cases,
they are covered by the borders of the segments. With the Coleoptera, the
stigmata are often situated so high upon the back as to be concealed by the
elytra.® The number and position of the stigmata vary infinitely, and
are not invariable in the different conditions (larva, pupa and imago) of
even the same species. These variations are the least with the hemimeta-
bolic Insecta. But among the Hemiptera, the Naucoridae and Nepidae
form a remarkable exception in this respect. They have, excepting those
of the thorax, only two stigmata at the posterior extremity of the abdomen,
and which alone serve, probably, for respiration when these insects are in
the water ; with Nepa, and Ranatra, these anal stigmata are situated at the
base of a long tube formed by the union of two semicanals.® The small-
est number of stigmata, consisting of two situated adjacently at the posterior
extremity of the abdomen, occurs with the larvae of the Dytiscidae, Stratio-
mydae, Oonopidae, and some Tipulidae and Tachinariae. Sometimes these
two stigmata are situated at the extremity of a longer or shorter Respira-
tory tube (Sipho), surrounded by a circle of -stiff or pennifonn bristles. In
some cases this siphon is very long and articulated, and can be intussus-
cepted like the tubes of a telescope.® When these Insecta become pupae,
these stigmata are sometimes remarkably modified. The pupae of Culex
lose their anal siphon, and acquire, instead, two others which are infundi-
buliform and situated laterally between the prothorax and meso thorax.®
The pupae of Ft.ychoptera respire by means of a flexible siphon situated in
the neck.® With the Strepsiptera, the male, as well as the apodal female

4 In the larvae of the Lamellicornes *, see
Sprengel , loc. cit. Tab. I. fig. 1 (larvae of Geotru-
pes). Some Capricornes present, in their perfect
6tate, a very singular organization in this respect.
Their thoracic stigmata send olf not only several
large tr ache an trunks, but also an infinite number
of small branches ; see Pictet , Mem. <1. 1. Soc. d.
phys. &c. de Geneve, VII., 1830, p. 393, fig. 5, 6
( Hammaticherus heros ), or Ann. d. Sc. Nat. VII.
1837, p. 63.

•7 From this arrangement, the Dytiscidae and
Gyrinidae, which live in the water, must, in .order
to breathe, emerge the posterior part of their body
to draw fresh air under their elytra, whence it is
taken into the tracheae. The Notonectidae, Hy-
drophilidae, Parnidae, and other aquatic Coleop-
tera, respire under the water by means of a pro-
vision of air which, after their immersion, adheres
to the hairs of the legs. With Hydrophilus , the
renewing of this air occurs in a very remarkable
manner. They protrude only their antennae out
of the water, and. bending them backwards, thus
establish a communication between the external air
and that adhering to the under surface of the body;
see Nitzsch, in Rcil's Arch. II. p. 410, Taf. IX.

6 See Roeset , Insectenbelust. III. Taf. XXII.
XX III.; and L. Du four, ltecherch. sur les He-
rnipt. p. 244, PI. XVII. fig. 195, PI. XVIII. With
Nepa , it is true there are stigma-like rings on the
other abdominal segments, but they are closed, and
L . Dufour has properly called them false stig-

37*

mata. In the young age of these insects; these
false stigmata are open and situated in two pilose
grooves located under the belly at some distance
from the lateral borders, and which are prolonged
even to the end of the siphon, where they blend
into one. The air is conducted by these grooves
into the stigmata.

7 By this disposition of the stigmata, the larvae
of the Dytiscidae, Culicidae and Stratiomydae, are
obliged, in order to breathe, to rise to the surface
of the water, where they emerge only the stigmatic
orifices, and the air then adheres to the coronets of
hairs on the stigmata. Many Tipulidae, such as
Pty diopter a , communicate even more easily with
the air by means of their long, articulated, siphon-
tube ; see Swammerdamm , Bib. der Nat. Taf.
XXXI. fig. 5, Taf. XXXIX. ( Culex and Stratio-
mys) ; Lyonet, M4m. du Mus. XIX. PI. XVIII.
(10) fig. 1-3 (Pty diopter a). The parasitic larvae
of the Conopidae, and of Ocyptera of the Tachi-
nariae, which live in the cavity of the body of Cas-
sida , Pentatoma , Bombus and Andrena , obtain
the necessary air for their respiration by placing
the posterior extremity of their body, which has
two stigmata, in contact with a stigma ortrachean
trunk of the insect in which "they live : see L. Du-
four , Ann. d. Sc. Nat. X. 1827, p. 255, VII. 1837,
p. 16, PI. I. fig. 13.

8 See Swammerdamm , loc. cit.

9 See Lyoiiet , loc. cit. p. 4, 5.

THE IN SECT A.

438

§ 344.

pupae, respire by two stigmata situated on the sides of the cephalo-
thorax. <10)

Most of the acephalous larvae of Diptera have only four stigmata, of
which two are situated on the truncated extremity of the abdomen, and the
two others, smaller, upon the sides of the second segment of the body.
These last have sometimes a tubular form, and with some species, are even
divided digitiformly at their extremity/11' With the larvae of many Syr-
phidae and Tachinariae, the two posterior stigmata consist of two siphons,
which are often fused into one/12' The larvae of the Coccidae have only
four stigmata situated on the under side of the middle portion of their
body/13' Most of the larvae of the Coleoptera, Hymenoptera, Lepidoptera,
as well as the cephalous ones of the Diptera, have numerous stigmata situ-
ated on each side in the middle of the segments of the body, and which
are never wanting, constantly, except with the sec<$ad and third thoracic,
and the last abdominal segments.

§ 344.

The numerous differences of the trachean system a’ in the various
families of the Insecta may be classed under two principal forms.

1. With the first and most common, there are two large lateral trunks
upon the sides of which open trunks which arise from the stigmata. From
these lateral trunks branch off' tracheae to the various parts of the body.

2. With the second form, the trunks which arise from the stigmata or
trachean branchiae, directly ramify over the organs, but give off, both
forwards and backwards, branches of communication to the neighboring
trunks. The branches of one and the same segment frequently inter-
anastomose by transverse trunks.

Often these two forms of tracheae coexist in the same individual. In
many cases, the secondary tracheae, in opening into the main trunks, are
dilated into a large vesicle, or have upon their course numerous similar
vesicles which give the whole system a varicose aspect.

Among the Aptera, the trachean system is of the first form with the
Pediculidae, Nirmidae, and Poduridae/2' But the Lepisinidae form an
exception in this respect, each of their stigmata opening into a trunk,
which, without anastomosing wdth the neighboring trunks, is isolatedly
ramified/3'

With the Hemiptera, the trachean system presents many modifications.
The trunks arising from the stigmata, sometimes ramify without anastomos-
ing, and sometimes open into two lateral trunks. The musical Cicadidae

10 See my Memoir in Wiesmann’s Arch. 1843,
I. Taf. VII.

11 See Bouche , Naturgesch. d. Insekt. Taf. V.
VI. ; L. Dufour , Ann. d. Sc. Nat. XII. 1839,
PI. II. III., and XIII. 1840, PI. III. and I. 1844,
PI. XVI .(Tachina, Anthomyia , Ilelomyza, Sapro -
myza , Piophila , &c.).

1 2 The siphon is very long, articulated, and situ-
ated at the extremity of the body with the larvae of
Eristalis ; see Reaumur , M6m. loc. cit. IV. PI.
XXX. XXXII.

13 See Bunneister , Handb. &c. II. Taf. I. fig.
10-12.

1 See, beside the works of Burmeister and La-
cordaire, the work of Marcel de Serres , in the
M6m. du Mus. IV. p. 313.

2 With the Poduridae, the six trachean branches
given off from the two main trunks, have each an
oval dilatation ; see Nicolet , loc. cit. p. 47, PI. IV.
fig. 3.

3 Gutrin (Ann. d. Sc. Nat. V. 1836, p. 374)
thinks that the trachean system is wanting with
Machilis ; but this must be incorrect, for Bur-
meister (Isis, 1834, p. 137) has observed this sys-
tem with Lepisma, with which it had for a long
time before been sought in vain. I have very dis-
tinctly observed it in Machilis , as well as in Le-
pisma, and its organization is the same in both.
The vesicles which, with Machilis , are situated on
the sides of the abdominal appendages, and which
Guerin thinks are respiratory organs, must have
another function.

$ 344.

THE INSECTA.

439

and the Pentatomidae, have varicose tracheae. With dead, a, there are
two of these vesicles situated at the base of the abdomen distinguished for
their very large size.<4) With Nepa, the primary trunks pass into the two
lateral trunks, and form transverse anastomoses which extend from one
side of the body to the other. In the thorax, the two lateral trunks form
several large vesicles, between which arise, upon the sides, two other trunks
which send an infinite number of very fine branches to the thoracic
muscles.®

With the Diptera, this system is of the first form. It often presents,
especially with those having a large and short abdomen, vesicular dilatations
of which there are two, situated at the base of the abdomen, very large
and distinct, sometimes filling nearly the whole abdominal cavity.® It is,
moreover, with the larvae of this order, that this form of tracheae is most
completely represented. The two lateral trunks are connected by the same
number of transverse anastomoses as there are segments of the body.®

With the Lepidoptera in all their states, this system is also of the first
form.® With the imagines of some Sphingidae, Bombycidae and Noctui-
dae, whose flight is continual, there are numerous vesicular dilatations and
appendages of the tracheae.®

The tracheae of the Hymenoptera, which, throughout, are of the first
form, send off from their two principal trunks numerous transverse anas-
tomoses, and usually present vesicular dilatations at many points.1® Of
these last, those situated on the abdominal portion of the two trunks are
very large, and often contiguous, so that the trunk to which they belong
appears like a large sac constricted from point to point. (U> Sometimes
there are only two of these vesicles, which are distinguished from the rest
by their enormous volume, situated at the base of the abdomen. (12) With
the larvae, there are found, pretty commonly, two main trunks connected
by transverse communicating tubes. (13)

4 See Burmeister , Handb. &c. II. Taf. I. fig.
10-12 (Coccidae) •, L. Du four , Recherch. loc. cit.
PI. XVII. fig. 194 ( Tetyra ), and Car us, Analekt.
&c. p. 156 {Cicada).

5 See L. Du four, Recherch. &c. p. 244, PI.
XVIII.

6 With the Muscidae, Syrphidae, Tabanidae,
Asilidae, Leptidae, &c. For the trachean system
of the larva and pupa of Sarcdphaga haem or -
rhoidalis, see L. Du four, Mem. presents. &c.,
IX. p. 572, PI. II.

7 Swammerdamm , Bib. der Nat. Taf. XL. fig.
1 (larva of a Stratiomys) ; Bouchi , Naturgesch.
d. Insekt. Taf. VI. fig. 1 (larva of an Anthomyia ),
and L. Dufour, Ann. d. Sc. Nat. XII. 1839, PI.
I.-IH.

8 Lyonet , Traits, PI. X. XI. (larva of Cossus
ligniperda). Wrhile the Syrphidae and Muscidae
are passing into their pupa-state, the posterior
stigmata disappear, the two anterior ones alone
remaining active. With the Syrphidae these last
often appear as two short tubes inserted on the cer-
vical region.

9 See Sprengel , loc. cit. Tab. III. fig. 24 {Sphinx
ligustri). Sometimes the number of these append-

* [ § 344, note 10.] See Newport (On the form-
ation and use of the air-sacs and dilated tracheae
in Insects, Trans. Linn. Soc. June, 1847) ; these
sacs are formed during the metamorphoses of the
insect, and he adopts the view of Hunter, that the

ages is reduced to two large aeriferous reservoirs
situated in the thorax ; see Suckow , Anat. physiol.
Untersuch. p. 36, Taf. VII. fig. 30 {Gastropacha
pint).

10 These dilatations are wanting with the Cynipi-
dae, Chalcididae, and some Ichneumonidae. For
the trachean system of the Hymenoptera in general,
see L. Dufour, Recherch. sur les Orthopt. p.
374*

11 With the Apidae, Andrenidae, Vespidae and
Bembecidae *, see Brandt and Ratzeburg, Mediz.
Zool. II. Taf. XXV. fig. 30 {Apis mellifica ), and
Newport , Philos. Trans. 1836, PI. XXXVI. or
Cyclop. &c. II. fig. 436 {Bombus terrestris).

12 With many of the Tenthredinidae, with Myr-
mosa , Scolia , Crabro , Pompilus , Sphex, &c.

13 See Swammerdamm, Bib. der Nat. Taf.
XXIV. fig. 1 (larva of a bee). According to the
observations of Ratzeburg (Die Ichneumon, d.
Forstinsekt. p. 63, 81, Taf. IX.), the parasitic
larvae of Microgaster and Anomalon are very
singular. When young, they have no traces of
tracheae, and respire, perhaps, by means of a cau-
dal appendage enveloped by a thin membrane.

vesicles serve chiefly to enable the insect to alter
its specific gravity at pleasure during flight, and
thus diminish the muscular exertion required dur-
ing these movements. — Ed.

440

THE INSECTA.

$ 345.

The true Neuroptera, in all their states, have a pretty simple trachean
system provided with two lateral trunks. But with the Orthoptera, on the
contrary, this system is usually very complicated. It is, indeed, less so
with the Blattidae, Forficulidae, Ephemeridae, and Perlidae ;<14> but with
the Libellulidae, the two lateral trunks are very large and arise from the
trachean branchiae together with two other trunks. a5> With the other
Orthoptera, the tracheae are very numerous and disposed according to the
second type or form, their trunks being connected by a multitude of volu-
minous, longitudinal, and transverse anastomoses, giving the whole a reti-
culated aspect. <16) With the Acrididae, most of the transverse anastomoses
have large air-reservoirs on their course. aT>

With the Coleoptera, the tracheae are always highly developed, and
disposed, with the larvae, after the first type, but with the imagines, after
the second. <18> With these last, the anastomosing canals, which connect the
primary trunks, are often double. <19> With the Palpicornes, and Lamelli-
cornes, this system is most highly developed, — the fine as well as the
larger tracheae having a multitude of terminal vesicles. <20>

CHAPTER VIII.

t*

ORGANS OF SECRETION.

I. Urinary Organs.

§ 345.

The Malpighian vessels, which are widely spread among the Insecta in
all their conditions/1' must now, since uric acid has been detected in their
secretion, be regarded as Kidneys.®

14 See Swammerdamm , Bib. der Nat. Taf. XIV.
and Carus , Entdeck. Ac. Taf. III. (larva and pupa
of an Ephemera).

15 Suckow , in Heusinger's Zeitsch. II. Taf. I.

II. (larva and imago of an Aeschna).

10 With the Locustidae, Achetidae and Mantidae ;
see L. Dufour, Recherch. sur les Orthopt. Ac. p.

269, PI. I. fig. 1 ( Oedipoda ), and Marcel de Serres ,

M6m. du Mus. IV. p. 331, PI. IV. (16) (Mantis),
also in Isis, 1819, p. 627, Taf. IX.

17 Marcel de Serres , loc. clt. PI. III. (15)

( Truxalis ), and L. Dufour , loc. cit. PI. I. (Oedi-
poda).

13 See Burmeister , Trans. Entom. Soc. I. PI.

XXIV. fig. 9 (larva of Calosoma sycophanta),
and Audouin, Ann. d. Sc. Nat. IX. 1826, PI.

XLIII. fig. 3 (Lytta vesicatoria).

19 See L. Dufour , Ann. d. Sc. Nat. VIII. 1826,
p. 23, PI. XXI. bis. fig. 1, and Pictet , M£m. de
Geneve, VII. p. 397, fig. 6 (Hammaticherus
heros).

‘■N Swammerdamm, Bib. der Nat. Taf. XXIX.
fig. 9 (Geotrupes nasicornis ), and Straus , Con-
sid. Ac. PI. VII. (Melolontha vulgaris). See,
also, for the Coleoptera in general, L. Dufour ,

Ann. d. Sc. Nat. VIII. 1826, p. 22.

1 As yet only Coccus , Chermes, and the Aphi-
didae, have been found wanting the Malpighian ves-

sels *, see Ramdohr , Verdauungswerk. d. Insekt.
p. 198, Taf. XXVI. and L. Dufour , Recherch.
sur les Hemipt. p. 116, fig. ill. I have been
unable to find them with the Strepsiptera in their
various stages of development. The male imagines
of Xenos Rossii, alone, have presented to me, at
the extremity of the digestive canal, a singular
glandular appendage resembling a cribriform lobe,
and which serves, perhaps, as a urinary organ.

2 For a long time the Malpighian vessels were
regarded as biliary organs, when Rengger ex-
pressed the opinion that they were urinary organs,
without, however, having demonstrated the pres-
ence of uric acid in their secreted product (Phys-
iol. Untersuch. fiber die Haushalt. der Insekt.
1817, p. 27). This chemical proof was furnished
by Brugnatelli and JVurzer (Meckel's Deutsch.
Arch. II. 1816, p. 629, and IV. 1818, p. 213), with
Bombyx mori. Subsequently, the existence of this
acid has been confirmed by Chevreul with Melo-
lontha vulgaris (Straus, Consid. Ac. p. 251),
and by Audouin with Lucanus cervus and Po/is-
tes gullica (Ann. d. Sc. Nat. V. 1836, p. 129).
See, also, Meckel, Ueb. die Gallen — und Ilarnor.
gane der Insekten, in his Arch. 1826, p. 21, and
Groshans, De System. uropo£t., quod est Radiat.
Articulat. et Mollusc. Acephalorum. 1837, p. 39.

§ 346.

THE INSECTA.

441

These always consist of several very long small tubes which, either
separately, or by means of one or two common excretory ducts, are inserted
upon the posterior or pyloric extremity of the stomach. These ducts are
sometimes dilated, bladder-like, at their point of insertion. The opposite
extremity of these uriniferous canals either terminates caecally, or passes
arcuately into that of another. When, as is usual, they are very long,
they embrace the digestive canal with numerous irregular convolutions.
With certain species, they creep, by their anterior extremity, between the
tunics of the stomach, or by their posterior between those of the colon ; this
remarkable relation has often led to the opinion that these organs have
two outlets into the digestive canal.®

These vessels are yellowish or brownish in color, and often slightly vari-
cose.® They are composed of an external homogeneous tunic tilled inter-
nally with cells. These last are very large, and are disposed rather in
rows, than adjacently ; and nowhere can there be perceived in the interior
of the vessels a glandular canal defined by a special epithelium. Each cell
contains a clear, colorless nucleus, and a multitude of very fine granules
which appear black by direct light, but by reflected light present a dirty-
yellow or brown, rarely a green or red, aspect.® The granular contents
of the cells, which give to these vessels their peculiar color, are scattered,
when the cells are ruptured, through the intercellular spaces, and flow
gradually into the digestive canal, Thus excreted, they accumulate in the
colon or in its caecal appendage, and are evacuated with the faeces, or
separately, as a troubled liquid of a color varying according to the
species.®

§ 346.

The Malpighian vessels present numerous modifications as to their num-
ber, their length, their points of insertion, and their modes of grouping, in
the different orders of the Insecta.®

With the Aptera, they are of median length ; with the parasitic species,
and with the Lepismidae, they are four in number ; and six with the Pod-
uridae.®

The Hemiptera have never more than four of these vessels, which are
pretty long, whose extremities are looped with the Ilydrocorisae and many

3 L. Dufour has clearly demonstrated the usual
caecal terminations of these vessels 5 see Ann. d.
Sc. Nat. XIV. 1840, p. 231, PI. XI. fig. 11 (larva
of a Mordella :), and XIX. 1843, p. 155, PI. VI. fig.
9 (Hammatic herns heros).

4 The uriniferous canals of Melolontha vulgaris
and Sphinx ligustri form, in this respect, a re-
markable exception. In a great part of their
course, they have on each side short caeca, pecti-
nately disposed j see Ramdohr , Abhandl. &c. Taf.
VIII. fig. 1, 2 ; L. Dufour , Ann. d. Sc. Nat. III.
1823, PI. XIV. fig. 4, 5 •, Straus , Consul. &c. PI.
V. fig. 6,10 (Melolontha) ; and Newport. Cyclop,
ioc. cit. p. 974, fig. 432 (Sphinx).

•r> For the intimate structure of these vessels, see
II. Meckel , in Muller's Arch. 1846, p. 41, Taf. II.

6 With the holometabolic Insecta, the urine is
evacuated isolately, especially when they approach
the completion of their pupa-state. It is well
known that the Lepidoptera, when bursting from
their pupae, emit a considerable quantity of urine,
of a variable color. In the larva and pupa of

Myrmelcon , it is gradually accumulated to a large
quantity of a rose-color, in the digestive tube, and
which the perfect insect immediately discharges on
leaving the pupa-envelope, as a solid or elongate
ovoid body. Reaumur (Mem. VI. 10 mem. PI.
XXXIV. fig. 12, 13) and Roesel (Insektenbelust.
III. p. 123, Taf. XX. fig. 28, 29) have taken this
urinary concretion for the egg of this insect. Some-
times there is precipitated in the urine, red crystals
of a quadra-pyramidal form 5 for example, with
the larvae of Sphinx and Ephemera.

1 For these modifications in the different orders
of Insecta, see the figures belonging to Ram-
dohr's work (Verdauungswerkz. &c.) 5 those of
Suckow , in Ileusinger's Zeitsch. III. and L. Du-
four , Sur les vaisseux biliares ou le foie des In-
sectes, in the Ann. d. Sc. Nat. XIX. 1843, p. 145,
PI. VII.-IX.

2 See Treviranus , Verm. Schrift. II. Taf. III.
fig. 1 (Lepisma), Swammerdamm , Bib. der Nat.
Taf. II. fig. 2 ( Pediculus ), and Nicolet , loc. ciL
PI. IV. fig. 2 (Podura).

442

THE INSECTA.

§ 346.

of the Geocorisae.® With some species, their excretory ducts form one or
two vesicular dilatations situated above the colon/3 4 * 6 7 8 9 10 11’ It is only with a few
Geocorisae, and with the Cieadidae, that the extremities of these canals are
free.® With this last group, and with the Cercopidae, they creep with a
portion of the intestine, between the tunics of the ante-stomach, before
opening into the lower extremity of the true stomach.®

With the Diptera, there are four long uriniferous vessels. The Culici-
dae and Psychodae, alone, by exception, have five.'71 With very many
species, these canals are united in twos, and open, by a common excretory
duct, into the lower extremity of the stomach.® Loop-like anastomoses
occur only with the Tipulidae, Leptidae, and Bombylidae. ®

With the Lepidoptera, there are nearly always six long, free, uriniferous
tubes, which open into the stomach by two excretory ducts. ao>

The Hymenoptera are distinguished for their considerable number of
these vessels, which are usually short and surround the pylorus in numbers
of twenty to one hundred and fifty. (11) With the Orthoptera, these vessels
are inserted in a similar manner, <12) but are often much more numerous/1®
The Termitidae, alone, form an exception, — having only six.a4’

The true Neuroptera are distinguished from the Orthoptera in that their
vessels of this nature are long, flexuous, and only six to eight in number/15’
With the Ooleoptera, they are usually long, make numerous convolutions,
and never exceed four or six in number/16’ When four, they are nearly
always joined by twos at their extremity ; and when six, they are often
attached by their extremities to the colon/17’

The urinary vessels of the larvae and pupae resemble somewhat those of the
perfect Insecta/18’ With the larvae of certain Hymenoptera, and Orthoptera,

3 With the Naucoridae, Nepidae, with Saida ,
Capsus and Reduvius. With Dorthesia , the
four canals form also two short loops *, see L. Du-
four, Recherch. &c. p. 19, PI. I. -IX.

4 Pentatoma , Tetyra , Pyrr/iocoris , Lygaeus,
Gerris , Stenocephalus.

3 Cimex , Ploiaria , Mir is, Alydus and Coreus.
In the last two genera the uriniferous canals, free,
terminate at the pylorus in a common reservoir.
With Alydus , Aradus , Aneurus; Cixius , Issus ,
and Asiraca, they unite in twos in a common ex-
cretory duct. With Psylla , they consist only of
four rudimentary caeca; see L. Dufour , Recherch.
loc. cit.

6 It was a long time before there was an exact
idea of the canals with Cicada. Doyire (Ann.
d. Sc. Nat. XI. 1839, p. 81, PI. I.) was the first
who perceived that they penetrated between the
tunics of the stomach *, but he supposed they re-
appeared on its surface after a short course. He
did not, therefore, attribute to these insects, only
two uriniferous vessels. This last error has been
rectified by L. Dufour (Ibid. XII. p. 287).

7 See L. Dufour , Ann. d. Sc. Nat. XIX. loc.
cit. PI. VIII. fig. 26 ( Anopheles).

8 With the Muscidae, Oestridae, Conopidae,
Syrphidae, and Ilippoboscidae. With the Stratio-
mydae, the four canals unite into one excretory
duct j see Swammerdamm , Bib. der Nat. Taf.
XLI. fig. 6 (Sfraliomys) ; L. Dufour, loc. cit. PI.

VIII. fig. 28 (Sargus).

9 Ramdohr , loc. cit. Taf. XX.

10 With Pterophorus and Yponomeuta, Suclcow
has found only four uriniferous vessels (loc. cit. Taf.

IX. fig. 159, 161).

11 See L. Dufour , Recherch. sur les Orthopt.
PI. in.-X. The smallest number of these canals
is found with the Formicidae, Cynipidae, and Ich-
neumonidae.

12 With the Ephemeridae, alone, the form of
these canals is somewhat different, in that their free
extremities are nearly always thickened, and that
the excretory ducts take one or two spiral turns.

13 See L. Dufour, Recherch. sur les Orthopt.
&c. PI. I. -IV. XI. XIII. Gryllotalpa is distin-
guished from the other Orthoptera in that the
urinary canals are disposed fasciculate and termi-
nate in a single excretory duct.

14 L. Dufour, Recherch. loc. cit. PI. XIII. fig.
196.

13 L. Dufour, Ibid. PI. XI.-XIII. There are
six of these vessels with the Phryganidae, Sialidae,
Panorpidae, Rhapididae : and eight with the Myr-
meleonidae and Hemerobidae.

16 There aie four urinary vessels with the Cara-
bidae, Staphylinidae, Gyrinidae, Palpicornes, La-
mellicornes, Cantharidae, and Buprestidae *, six
with the Byrrbidae, Nitidulidae, Dermestidac,
Cleridae, Meloidae, Pyrochroidae, Bmchidae, Bos-
tricidae, Capricornes, Chrysomelidae, and Cocein-
ellidae.

17 For the uriniferous canals of the Ooleoptera,
see, beside Ramdohr, and Suckow, loc. cit., L.
Dufour, Ann. d. Sc. Nat. 1824, 1I.-IV. ; 1884, I.
PI. II. III.; 1840, XIII. PI. V. VI.; XIV. PI. XI.;
XIX. PI. VI. With Donacia, the 6ix vessels
have a very peculiar aspect. Two pairs unite
loop-like at their posterior extremities, and their
anterior ends unite in a common reservoir ; while
the third pair are free and open isolately at the
pylorus •, see L. Dufour , Ann. d. Sc. Nat. 1824,
IV. PI. VII. fig. 7, 8, and 1844, XIX. PI. VII. fig.
10.

18 Beside Ramdohr , and Suckow , loc cit., see L.
Dufour, Ann. d. Sc. Nat. XII. 1839, PI. I.; XIII.
PI. V.; and XVIII. PI. IV. (larva of a Tipulide, a
Sapromyza , a Pyrochroa , and of a Cetonia , iVc.) ;
De Haan , Nouv. Ann. du Mus. IV. PI. XVI. -XIX.

§ 347.

THE INSECTA.

443

alone, their number is smaller, ft9) ancl with those of the Lepid'optera. the
extremities of the six tubes of this kind are insinuated between the tunics of
the colon; while, with the imagines they are freed20’ With the Bupres-
tidae, the larvae have six, but the imagines only four, of these vessels.®1’

II. Organs of Peculiar Secretions.

§ 347.

A great number of the Insecta, in both their larval and their perfect state,
have glandular organs which secrete very varied products remarkable for
their specific properties.

Many species have a secretory appai’atus analogous to the cutaneous
glands of the Vertebrata, which have received the name of Glandulae odor-
iferae. These consist of round follicles situated under the skin, whose
very short excretory ducts open between the segments of the body, or be-
tween the articulations of its extremities. Their product emits a powerful
odor, and, with some species, is evacuated in the form of droplets,'” or,
with others, covers the whole surface of the body, being perceived only by
its odor.®’ The disagreeable odor emitted by the Bugs is due to a fluid
secreted by a single, yellow, or red pyriform gland, situated in the centre
of the metathorax, and opening between the posterior legs.'3’ With other
Insecta, there are analogous secretory organs, concealed in the posterior
extremity of the abdomen, which copiously emit a fetid, troubled liquid,
through an orifice situated by the side of the anus. These Anal Glands are
usually double, and consist of simple follicles whose secretory product
accumulates in round, or oblong contractile reservoirs.'4’ With many

(larva of various Lamellicornes); and Burmeister ,
Trans, of the Entora. Soc. I. PI. XXIV. fig. 10 (larva
of a Calosoma), and his Abhandl. z. Naturges-
chichte d. Calandra, loc. cit. fig. 3.

19 The larvae of the Apidae and Vespidae have
only four uriniferous vessels ; see Swam mcrdamm,
Bib. der Nat. Taf. XXIV. fig. 6 (larva of a bee) ;
Suclcow , in Heusinger's Zeitsch. III. Taf. VI. fig.
180, and Ramdohr , loc. cit. Taf. XII. (larva of a
Vespa ) ; finally, Rathki , in Mailer's Arch. 1844,
p. 36, Taf. II. (larva of a Gryllotalpa).

20 See Lyonet , Traite, &c., PI. XIII., and
Suckow , Anat. u. physiol. Untersuch. Taf. II.

21 See f. Du four , Ann. d. Sc. Nat. XIV. 1840,
p. 114. Loew (Entom. Zeit. 1841, p. 37, fig. 3) did
not, probably, observe these canals in the larva of
Buprestis inariana ; for, otherwise, he would not
have regarded as such the two caecal appendages
at the upper extremity of the stomach, and which
the Buprestidae have also in their imago-state (see
§338).

1 With Euprepia , and Zygaena , a fluid of this
kind, yellowishly transparent, exudes under the
collar 5 and with many Meloidae, Chrysomclidae,
and Coccinellidae, it escapes from the knee-joints.
The larvae of these last Coleoptera, as well as those

of many Tenthredinidae, emit droplets of fluid from
the surface of their skin from the least touch. Very
often the odor of this fluid reminds one of fresh
poppy-juice. The fluid emitted from the cephalo-
prothoracic articulation, with Colymbetes and
Dytiscus , has a very nauseating order. I am un-
able to decide whether or not the transparent liquid
which escapes with various Aphididae through two
tubes on their abdomen, belongs to this same cate-
gory of secretions.

2 Certain Phryganidae, Ilemerobidae, Crabron-
idae, Scoliadae, Ichneumonidae, &c., emit specific
odors without the secretion of their Glandulae
odoriferae being visible.

3 See L. Dufour , Recherch. loc. cit. p. 266, PI.
XVII. fig. 194. Moreover, the opinion that all the
Bugs emit a bad odor is incorrect *, for with many,
as for example Syromastes , the Glandulae odori-
ferae exhales a very agreeable odor resembling that
of a fine bergamot pear.*

4 These anal glands, which Burmeister (Handb.
I. p. 157), Grant (Outlines, &c., loc. cit. p. 584)
and other anatomists have mistaken for urinary
organs, consist, with the Dytiscidae and Gyrinidae,
of two simple, long and flexuous caeca, whose re-
servoirs, having two short excretory ducts situated

* [ § 347, note 3.] With Belostoma , the odor-
iferous glands consist of two pretty long caecal
tubes situated in the metathorax, beneath the other
viscera, and extending into the anterior part of the

abdomen. They open externally between the
coxae of the posterior legs. See Leidy , loc. cit. p.
64.— Ed.

444

THE INSECTA.

§ 347.

Coleoptera, these anal glands secrete a caustic fluid which has a penetrating
and more or less aromatic odor. They are somewhat ramified, or composed
of vesicles disposed botryoidally, and open into one or several long, excre-
tory ducts. (,5) These last open into two pyriform, muscular reservoirs, whose
powerful contractions expel, as a means of defence, the secreted fluid.® The
Formicidae, also, have, in the anal region, a glandular apparatus from
which they eject a capstic, acid fluid. This apparatus is single and com-
posed of one reservoir whose neck opens into a simple tube.® The larvae
of Harpyia, also, defend themselves by ejecting an irritating liquid secreted
by a glandular sac, which opens directly back of the head on the under
surface of the first segment of the body.

Among the Hymenoptera, the females of the Vespidae, Fossores, An-
drenidae, and Apidae, have, in the anal region, a glandular apparatus which
secretes a poisonous fluid introduced by means of a hollow sting into the
tissues of their prey or enemies.® This Poison-apparatus is composed of
two long tubes which are sometimes very ramose.® The intimate struc-
ture of these tubes resembles that of the salivary glands. (10) The two
poison-glands are sometimes isolated, sometimes united into a common
canal, and their product is poured into a pyriform reservoir, which has
thin but contractile walls, whose longer or shorter excretory duct opens
into the sting. (11) This sting is formed by the intimate union of two lateral
pieces, and plays in a cleft horny sheath. Often, its extremity is covered
with backwardly-pointing denticles. (12) Both the sheath and the sting have,
at their base, a peculiar muscular apparatus by which they are protruded
and withdrawn.

near the arras, ejaculate a highly stinking liquid.
With the Silphidae, where this apparatus is single,
the reservoir opens laterally into the rectum ; see //.
Meckel , in Muller's Arch. 1846, p. 47, and L. Du-
four , Ann. d. Sc. Nat. VIII. 1826, p. 15, HI. id. X.
fig. 3, 4, 5, PI. XIII. fig. 5, 7 (Dytiscus,Gyrinus
and Silpha). With Gryllotalpa , the anal glands
consist of small lobular bodies inserted on the re-
servoir which receives their product : see L. Du-
four, Recherch. sur les Orthopt, &c., p. 346, PI.
II. fig. 19.

5 With the Carabidae, and Staphylinidae ■, see
L. Du four, Ann. d. Sc. Nat. VIII. 1826, p. 6 ;
II. PI. XX. XXL; III. PI. X.; and VII. PI. XIX.
XX.; J. Muller , De Glandul. Struct. &c. Tab. I.
fig. 13-18 ; and Stein , Vergl. Anat. u. Physiol, d.
Insekt. 1847, Taf. I. fig. 4, g. g. (Dianous) and
Taf. III. fig. 3, 1. n. ( Oxytelus ).

6 With Brachinus , as is well known, this prod-
uct is so volatile as to immediately become gase-
ous on its ejection.*

7 See L. Dufour, Recherch. sur les Orthopt. &c.
p. 413, PI. VII. fig. 86.

8 The Bees, which have a poison-apparatus of
this kind, ought to be regarded as females whose
genital organs are undeveloped. Many fossorial
Hymenoptera, which feed their young with insects,

* [ § 347, note 6.] For the peculiar glandular
apparatus for this purpose, with Brachinus , see
Karsten , in Muller's Arch. 1848, p. 367. Con-
trary to other Zootom ists, this observer regards
this apparatus as of a urinary nature, for he states
that an analysis of its secretion furnishes a product
analogous to urea. — Ed.

wound these last with their sting, that they may be
mastered, and conveyed the more easily to the
nest. Indeed, some carry their prey into their
nests transfixed with the sting. (See my Observ.
quaed. de Oxybelo atque Miltogramma, 1841, p.
11.) The wound does not always kill the insect,
but simply disables it, so that they remain fresh
for several days by the side of the larvae for whose
food they are to serve.

9 There are two simple tubes with Vespa , Scotia,
Crabro , Halictus , Apis, kc. ; but they are ram-
ified with Pompilus, Phitant/ius, Larra, Bom-
bus, kc.

10 For the intimate structure of these poison-
glands, see //. Meckel , in Muller's Arch. 1846, p.
45, Taf. III.

11 This poison-apparatus is described more in
detail in the works of Swammerdamm , Bib. der
Nat. ]). 183, Taf. VIII. (Apis); Brandt and
Ratzeburg, Mediz. Zool. II. p. 203, Taf. XXV. fig.
39-42 ; Ramdohr , Abhandl. iib. d. Verdauungs-
werkz. kc. Taf. XIV. fig. 5 (Pompilus), and
Suckow, in Heusinger's Zeitsch. II. Taf. XIV.
fig. 38, 46 (Apis and Crabro).\

12 See Swammerdamm, loc. cit. Taf. XVIII. fig.
3.

t [ § 347, note 11.] The poison of the poison
apparatus in the Hymenoptera has been investi-
gated by Will (Schleiden and Froriep's Not.
1848, Sept. p. 17) who found, with Ants, Bees, and
Wasps, that this product consisted of formic acid
and a whitish, fatty, sharp residuum, the former
being the poisonous substance. — Ed.

§347.

THE INSECTA.

445

There is another category of secretory organs which, with many females,
open at the base of the ovipositor, but as they are intimately connected
with the act of oviposition, they will be most properly described with the
genital organs/131

A very large majority of the holometabolic Insecta have, in their larvae-'
state, silk-organs, the secretion of which they use, some, to weave a cocoon
when about to pass into the pupa-state, or to close a hollow refuge they
have sought ; others to fasten together foreign bodies for the fabrication of
their retreat. These organs are, therefore, most developed at the period
when these insects approach their pupa-state ; but with the larvae of the
Psychidae, Tortricidae, and Lasiocampadae, they are already active during
the first epochs of life. The silk-secreting portion of this glandular apparatus
consists of two long, somewhat llexuous, thick-walled caeca, situated on the
sides of the body, and continuous, in front, into two small excretory ducts,
whose common orifice is on the under lip, and usually at the extremity of
a short tubular protuberance/141 With the larvae of Myrmeleon, the silk-
apparatus is very remarkable, for the rectum itself is changed into a large
sac and secretes this substance, which escapes through an articulated spin-
neret projecting from the opening of the anus/151

With the Apidae, there is a very remarkable Wax-secreting apparatus.
This wax is elaborated by the Workers under the form of thin discs, which
are formed between the imbricated posterior legs, without there having
been discovered, as yet, in this region, the orifices of any special glands.
It must therefore be supposed that it is produced by an exudation from the
thin membranes which connect the different parts of the legs/161 Moreover,
many other Insecta have secretory products which transude through the
skin without the existence of any special glandular apparatus, and which
are hardened by the air like wax. These products are usually whitish,
pulverulent, filamentous, or flocculent substances, which catch upon the
surfaces of bodies/171

13 See § 350.

14 See Roesel, Insektenbelust. III. Class. I. Pap-
ilionum nocturnorum. Taf. IX. ( Bombyx ) ; Lyonet ,
Traits, &c., p. 498, PI. XIV. XV. (Cossus) ;
t iuc/cow , Anat. u. physiol. Untersuch. p. 29, Taf.
VII. fig. 31 {Gastropacha) ; Pictet , Recherch.
pour servir 5 l’hist. d. Phryganides, PI. III. fig. 1
(Phryganca). The decrease of these organs dur-
ing the pupa-state has been very carefully detailed
by Herald , Entwickelungsgesch. d. Schmetterl., Taf.
III. and by Suckow , loc. cit. Taf. II. ( Pontia ,
Gastropacha ).

15 See Reaumur, Mem. &c. VI. PI. XXXII. fig.
7, 8 •, Ramdohr , Abhandl. &c. Taf. XVII. fig. 1.

1G Fur the intimate structure of the wax-secret-
ing portions of the skin with the workers of bees,
see Treviranus , Zeitsch. f. Physiol. III. p. 62,
225 •, and Brandt and Ratzeburg, II. p. 179, Taf.
XXV. fig. 18. The production of wax with bees has
lately been the subject of much research among
French naturalists. Milne Edwards has ad-
vocated the opinion before rejected by him, that this
substance is secreted by special glands. But L.
Dufour , after carefully-made researches, failed to
discover them. See the various memoirs on this
question in the Compt. Rend. XVII. and in the

* [ § 347, note 17.] See upon the subject of these
secretions Dujardin (M£m. sur 1’etude micros-

38

Institut. 1843, also in Froriep's neue Not.
XXVIII. XXIX.

It is, moreover, easy to be convinced of the ab-
sence of these glands with the bee-workers ; but
if certain Andrenidae are examined, there will be
found, on each side of their posterior tibiae, a small
pyriform follicle with an excretory duct, and which
secretes an oily substance.

If These cutaneous secretions are observed with
various Coccidae and Aphididae, whose entire bodies
they cover with a powdery or woolly substance.
With the females of Dorthesia, not only the entire
body is covered with a substance which forms a
solid white crust, but also the eggs after their depo-
sition are invested with a similar envelope and
thereby glued to the abdomen of the mother. With
many male Coccidae, this secretion forms, at the
posterior extremity of the abdomen, a bundle of
verjr diverging, long, white and perishable hairs.
With some Cicadidae ( Lustra and Plata), the
thorax and abdomen are covered, in places, by a
kind of mould of a similar origin. The larvae of
many Tenthredinidae (for example, Tentkredo
ovata ), as well as those of certain Coccinellidae
( Scymnus ), exude a liquid which, upon drying,
forms white fiocci.*

copique de la cire, in the Ann. d. Sc. Nat. XII.
1849, p. 250); his observations were made upon

446

THE INSECTA.

$ 348.

The Phosphorescent Organs of the Lampyridae and certain Elateridae,a8>
consist of a mass of spherical cells, filled with a finely-granular substance,
and surrounded by many numerous trachean branches. (19) This substance
which, by day-light, appears of a yellow, sulphur-like aspect, fills, with the
Lampyridae, a portion of the abdominal cavity, aud shines on the ventral
surface through the last abdominal segments, which are covered with a
very thin skin ; while, with the Elateridae, the illumination occurs through
two transparent spots situated on the dorsal surface of the prothorax. The
light produced by these organs so remarkably rich in tracheae, is undoubt-
edly the result of a combustion kept up by the oxygen of the air of these
vessels. This combustion explains the remission of this phosphorescence
observed with the brilliant fireflies, and which coincides, not with the move-
ments of the heart, but with those of inspiration and expiration. (20)

CHAPTER IX.

ORGANS OF GENERATION.

§ 348.

The Insecta always multiply by means of genital organs situated in
different individuals, a> and, invaluably, are provided with copulatory organs.!
With certain species, namely, with the Apidae, and Termitidae, the females

18 For *fhe phosphorescene of these Coleoptera,
Gee Carus, Analekt. &c. p. 168 ; Burmeister ,
Ilandb. I. p. 534, and Lacordaire ,' Introduct. &c.
n. p. i4o.

19 The intimate structure of these organs has
been studied with Lampyris italica by Peters
{Muller's Arch. 1841, p. 229), and by Morren
(Isis, 1843, p. 412). This last author says that this
insect contains phosphorus, but adduces no fact in
support of this assertion.

20 Matteuci has made numerous experiments on
the phosphorescence of Lampyris italica ; from
which it appears that the phosphorescent substance
burns by means of the oxygen contained in the
tracheae, without any increase of the temperature,
and without any indication of the presence of
phosphorus ; see Matteuci , Lecons sur les plu-
nom. phys. d. corps vivants, Paris, 1847, p. 151,
and Compt. Rend. XVII. 1843, p. 309, also in Fro-

various Insecta, among which were Dorthesia ,
Alaerodes , &c. The wax consists of fibres which
are perpendicular to the secreting surface, and is
a true product of the integument independent of
any special glandular apparatus. — Ed.

* [ § 347, note 20.] See, also, a note by me upon
the intimate structure of the phosphorescent organs
in Purophorus phosphorus , Proceed. Boston Soc.
Nat. Hist. 1850, p. 290. — Ed.

t [§ 348, note 1.] See, also, for cases of true
hermaphroditism in the Insecta, Wing (Trans, of
the Eat. Soc. London, V. p. 119) and Wesmatl
(Bull, do l’Acad. d. Brux. 1849, II. p. 378). — Ed.

ricp's neue Not. No. 583, p. 168, and in Schleiden
and Froriep's Not. No. 9, p. 135.*

1 Hartig has declared that certain species of
Cynips are hermaphrodites ; but Ratzeburg and I
have shown that this assertion is based on an erro-
neous interpretation of the organization of the
females of Cynips ; see Ger mar's Zeitsch. f.
Entom. III. p. 322, Taf. I.; and IY. p. 380, 396.

The true hermaphrodites which have as yet been
found in the other orders of insects, notably among
the Lepidoptera, ought to be regarded as monsters.
Klug (Verhandl. d. Gessellsch. naturf. Freunde in
Berlin, I. p. 363, and Jahrb. d. Inseckt. I. p. 254),
Ochsenheimer (Die Schmetterl. von EuropalV. p.
185) and Lefihvre (Ann. d. 1. Soc. Entom. IY.
1835, p. 145) have given a list of the cases of
hermaphroditism with insects. See also Burmcis-
ter , Handb. I. p. 3384

f [ § 348. J The copulatory organs of the Insecta
present wide and manifold variations, as has been
shown especially by the recent researches of La -
caze Dutliiers , Recherches sur l’Armure g^nitale
des Insectes, in the Ann. d. Sc. Nat. 1849, XII. p.
353, 1850, XIV. p. 17; also his Recherches sur
l’Armure g£nitale femelle des Insectes Orthopt^res,
id Ibid. XVII. 1852, p. 207, and Recherches sur
l’avmure g£nitale femelle des Insectes Il&nipt^rea,
Ibid. XVIII. 1852, p. 337, finally the same of the
Insectes Nevropteres, Coleopt^res, Dipt^res, in
Ibid. XIX. 1853, p. 25, et seq. — Ed.

$ 348.

THE INSECTA.

447

are much less numerous than the males. In the colonies of Bees, Ter-
mites, and Ants, there are, beside the males and females, a multitude of
neuter individuals known as the Workers or Soldiers.

The sexual parts of insects are developed chiefly during the pupa-state ;
but their rudiments exist already in the youngest larvae, with which the
sexes may then be distinguished.®

The female genital organs persist in a rudimentary germ-like condition
with many larvae of Bees, probably owing to the influence of nourishment,
for by increasing that of the workers these last may be raised to the rank
of females or Queens.®

The Aphididae are very remarkable in that they produce, for several
successive generations, only females which, in their, turn reproduce, but
viviparously and without the direct influence of the males.®

The genital organs of the Insecta are composed in general, of two symmet-
rical Ovaries, or Testicles, situated in the abdominal cavity, and of two
oviducts, or Deferent canals ( Tubae , or Vasa defer entia) which unite in a
common excretory duct ( Vagina , or Ductus ejaculatorius) opening back of

2 Herold (Entwickelungsgesch. d. Schmetterl.)
has made very interesting researches on this pre-
mature development of the genital organs with
Pontia brassicae , and which accord with the ob-
servations of Suc/cow (Anat. u. physiol. Untersuch.
p. 31, Taf. III. V.) on those of Gastropacha pini.
See, also, Herold , Disquisit. de Animal. Vertebr. car-
ent. in ovo format. Tab. I. fig. 9, or Ann. d. Sc. Nat.
XII. 1839, p. 186, PI. VII. fig. 8. To be con-
vinced that in the other orders of Insecta the geni-
tal organs are also developed at a very early
period, it is only necessary to cast a glance over
the figure which Suc/cow (Heusinger's Zeitsch.
II. Taf. X. fig. 9) has given of Aphrophora spu -
warm, and Z,. Dufour (Ann. d. Sc. Nat. XIII.
1840, PI. III. fig. 5) of Pyrochroa coccinea.

3 For the origin of the neuters with the Ilymen-
optera, see Treviranus, Zeitsch. f. Physiol. III.
p. 220. In all the bee-workers there are found

* f § 348, note 4.] The peculiar economical re-
lations of certain Hymenoptera (Cynips) referred
to above have received some explanation by the
researches of Frauendorf (Ilardinger Berichte iib.
d. Mittheil. v. Freunden d. Naturwiss. in Wien. IV.
p. 247, or Wiegmann's Arch. 1849, Th. II. p.
118), upon Gastropacha lancstris. He gathered
two nests of the larvae at the end of June, 1836 ;
by the middle of August the caterpillars had spun
up, and on Sept. 18, the first imago appeared, and
the second on Dec. 14 ; both of these were males ;
in the spring of 1837, some twenty individuals of
both sexes appeared; others, likewise, in the autumn
of 1837 ; others still in the following year, and the
last of them on the 4th of March, 1842. The pupa-
state of the last of the brood was therefore five and
a half years, while that of the first was only as
many weeks.

In regard to the alleged anomalous reproductive
relations of Psyche , they have received the special
attention of Siebold , who has quite cleared up the
subject (Ueber der Fortpflanzung von Psyche : Ein
Beitrag z. Naturgeschichte der Schmetterlinge, in
Siebold and Kolliker's Zeitsch. I. 1848, p. 93 ;
also in his Bericht iib. die entomol. Arbeiten d.
schles. Gesellsch. im J. 1850, or its transl. in the

vestiges of the ovaries and of the seminal receptacle.
See Rat ze burg , Nov. Act. Nat. Cur. XV. part II.
p. 613, Tab. XLVII. and my observations in Ger-
mans Zeitsch. IV. p. 375.

4 This mode of generation of the Aphididae (see
§ 350) quickly reminds one of that which Steen -
strup has called Alternate Generation. Certain
species of Ci/nips belong probably to the same cat-
egory, for their males have yet been undiscovered.
Hartig (Germans Zeitsch. IV. p. 398) has been
unable to find any individuals of this sex among
thousands of Cynips folii and divisa. Similar
observations have been made by L. Dufour (Re-
cherch. sur les Orthopt. &c. p. 527). It is to me
probable, also, that the capacity which many ento-
mologists attribute to Psyche of laying eggs with-
out a previous copulation is an example of alternate
generation.*

Transact, of the Entom. Soc. London, 1. 1851, p. 234.
In the first of these researches made upon the
genera Psyche and Fumea , there was no evidence
that, with the individuals of these genera, reproduc-
tion occurs in an anomalous manner, that is, with-
out the aid of the male ; on the other hand, the
facts of the well-developed character of the inter-
nal genital organs of the females, and of the capacity
of the male to impregnate the female while she is
concealed deeply in her case — these precluded the
hypothesis of Lucina sine concubitu. But sub-
sequent researches made upon Talacporia have
shown him that, with the individuals of this genus,
non-sexual reproduction does occur, presenting sim-
ilar phenomena and conditions as the generation of
the viviparous Aphides. It is proper to remark, how-
ever, that the carefully -made researches and exper-
iments of Speyer upon the genital organs and mode
of reproduction of Talaeporia lichenella , several
years before, had shown that two successive genera-
tions here occur without the presence of males ; see
his paper in the Entom. Zeit. 1847, p. 18. For the
phenomena and their interpretation of the develop-
ment of the viviparous Aphididae, see my note at
§ 355, end. — Ed.

448

THE INSECTA.

§ 348.

the anus. This duct has several double or single appendages, of which
one with the females serves as a seminal receptacle ( Receptaculum seminis ),
or as a copulatory organ ( Bursa copulatrix), while the others, in both
sexes, are true secretory organs. The vagina is often prolonged into a
horny ovipositor, and this same organ modified, with the males, is the Penis.

The Eggs of Insecta are very varied in their forms and colors. Exter-
nally, they are frequently marked by prominences and raised lines, forming
a very varied, and often a very elegant design.® Those of some Cynipi-
dae, Ichneumonidae, and Siricidae, have one of their ends prolonged into a
long, straight or curved thread.® With some Hydrocorisae they are oblong
and their posterior extremity is covered with long, stiff bristles.® They
have, usually, a very solid chorion, and a thin vitelline membrane. The
vitellus is composed of fat-vesicles more or less colored, which communicate
their color to the entire egg. The germinat.ive vesicle contains a germina-
tive dot which is often composed of several parts.®

These eggs are formed after two different types.

1. With the Orthoptera, and various Coleoptera, the germinative vesicle
is formed in the posterior extremity of the tubular ovaries, and is gradu-
ally surrounded by a mass of granular vitelline substance. This vitelline
mass continues to increase until, at last, there is formed on its surface a
chorion, at first soft, but which finally becomes solid. During the course
of this development, the eggs succeed each other in a row, and in this way
advance towards the opening of the ovarian tube.®

2. With the Lepidoptera, Diptera, Hymenoptera, Neurop'tera, Cicindeli-

dae, Carabidae, and Hydrocanthari, the mode of formation is wholly differ-
ent. The vitelline mass which is disposed around the germinative vesicle,
increases in the following manner : Between each two vitelline masses,

there appear a group of large vitelline cells whose contents are blended
with the subjacent vitelline mass; while, the chorion is developed from a
layer of vitelline cells, commencing by its inner portion. It gradually
extends over the vitelline mass and cells, and finally, when the vitellus has
reached a certain volume, closes at the upper portion of this last. The
epoch at which the eggs reach their maturity coincides, with the Lepidop-
tera, Tipulidae, and Ephemeridae, with the end of their pupa state, so that
these insects are able to deposit their eggs as soon as they have cast off
their pupa envelope ; while, with the Libellulidae, the Locustidae, and
especially the Apidae, the eggs are not matured in the ovaries until a long
time after.1®

With all Insecta, the sperm contains very active filiform spermatic
particles which become immediately stiff and looped when put in water.
These particles are developed in large cells whose involucrum finally dis-

5 Kirby anrl Spence (Einleitung, &c., p. 100, Taf.
XV.) have figured a great number of eggs of insects of
various forms. See, also, Burmeister , Ilandb. &c.
Taf. I. and L'icordaire , Introduction, &c., PI. I.

6 See L. Dnfour , Recherch. sur les Orthopt. fig.
128, 149 ( Cynips and Xiphydria ) ; liar tig, in
Wiegmann's Arch. 1837, 1. p. 151, Taf. IV. (Try-
phon , Paniscus , and other Ichneumonidae), and
in Germans Zeitsch. f. Entom. p. 327, Taf. I. fig.
5, 6 (Cynips).

7 The eggs of Ranatra have two long bristles *,
while, with those of Nepa , these last form a coro-
net; see Roesel , Insektenbelust. III. Taf. XXII.
XXIII., and L. Dufour , Recherch. sur les He-
mipt. PI. XVI.

8 See Wagner , Prodromus, &c., p. 9, Tab. II.
fig. 18-22.

9 See Wagner , Abhandl. d. physical, mathemat
Klasse. der Akad. zu Munich, II. 1837, p. 554,
Taf. II. fig. 1 ( Agrion ), and Stein , Vergl. Anat.
u. Physiol, d. Insekt. I. p. 47, Taf. IX. fig. 4, 8
(Telephorus and Acheta).

10 Herold was the first who observed this re-
markable mode of the fonfiation of the eggs with
the Lepidoptera ; see his Disquisit. &c. Tab. I. fig.
11-18, or Ann. d. Sc. Nat. XII. 1839, p. 195, PI.
VII. fig. 13-18. Researches even still more de-
tailed have been made by Stein , Vergl. Anat. &c.
p. 52, Taf. IX. fig. 2, 9, 1.3 (Pontia and Pterosti -
chus).

§ 849.

THE INSECTA.

449

appears, while the spermatic particles thus formed remain together for
some time and finally are united in fasciculi of variable forms. <u>

With many species, these bundles are disposed one after another, and
then united forming long, vermicular bodies. (12) Only gradually, as the
sperm mass passes along the deferent canals, are the spermatic particles
separated to unite again under new and remarkable forms. These last
consist of long, penniform bodies, having very singular movements, for
their free extremities oscillate to and fro without cessation. (13) A kind of
spermatophore is also observed in the female organs of many species
belonging to the Lepidoptera, Orthoptera and Coleoptera. It consists of a
peculiar hollow body, usually somewhat pedunculate, with pretty solid
albumen-like walls, and filled with spermatic particles. (l4)

I. Female Genital Organs.

§ 349.

The two Ovaries are always composed of a larger or smaller number of
tubes, whose free extremities are extremely small, but which gradually
increase in size to their point of insertion on the oviducts. From their
caecal terminations is prolonged a delicate thread, which, bound together
with the others, serves to attach the two ovaries to the thorax. (1) The

11 For the spermatic particles of the Insecta and
their development, see my memoir in Mutter's Arch.
1836, p. 30 ; and Kolliker , in the Neue schweiz.
Denkschrift. VIII. p. 24.*

12 See my memoir in Mutter's Arch. loc. cit. p.
38, Taf. III., fig. 16-18 ( Pontia ). These vermiform
bundles are observed not only with all the Lepidop-
tera, but also with certain Diptera and Coleoptera ;
see Loew, Horae anatom. lift. 1, 1841, p. 26, Taf.
II. ( Scatopse ), and Hammer schmidt , Isis, 1838,
p. 358, Taf. IV. ( Cleonus and various Lepidop-
tera). This last mentioned naturalist has, however,
taken these cords for gigantic spermatic particles,
to which he has given the name of Pagiura , Spiri-
lura and Cincinnura.

13 1 have discovered these penniform bodies
composed of spermatic particles in the Receptacu-
lum seminis of Locusta and Decticus ; see Nov.
Act. Nat. Cur. XXI. 1845, p. 251, Tab. XIV. XV.
Dujardin (Observ. au Microscop. 1842, PI. XI.
fig. 18, 19) had already perceived similar bodies in
the male organs of Tettigonia plebeja and Spho-
drus terricola. Stein (Vergl. Anat. &c. p. 106,
Taf. I. fig. 19 ( Loricera )) has also found them in
the seminal receptacles of the females of various
Carabidae.

14 Pyriform, short-pedunculated spermatophores
are found in the Receptaculum seminis of the

* [ § 348, note 11.] The spermatic particles of
the Insecta are described above, as well also by
fVagner and Leuckart (loc. cit. Cyclop. Anat. and
Phys.), as being invariably filiform. This is incor-
rect : it is true they are generally so ; as, for
instance, with all the Coleoptera, Lepidoptera,
Diptera, Aptera, Ilemiptera ; but with some fami-
lies of the other orders (the Hymenoptera, Neurop-
tera and Orthoptera) their form is quite different,
and I am only surprised that it has not before been
noticed. Thus, with the Libellulidae, Ephemeri-

38*

fecundated females of Locusta and Decticus (see
my memoir in the Nov. Act. Nat. Cur. loc. cit. p.
262, Tab. XVI. fig. 14, 15), while those observed
in the Bursa copulatrix of many Lepidoptera are
round and long-pedunculated. With the Coleop-
tera, spermatophores are often found, also, in the
copulatory pouch of the fecundated females. Their
forms vary considerably, and I may mention
specially those of Clivina fossor , which are elon-
gate and remarkable for their very long and twisted
peduncle •, see Stein , loc. cit. p. 91, Taf. I. VII.
VIII. The older entomologists took these sperm-
atophores for the penis which was detached in the
copulatory act — an opinion which I myself for-
merly entertained ( Muller's Arch. 1837, p. 399,
419) ; but, since, I have learned the true nature of
these bodies, and the rectification of this error,
made by Stein (loc. cit. p. 86), is perfectly correct.

l For the different dispositions of these tubes, see
J. Muller , Nov. Act. Nat. Cur. XII. p. 585;
Burmeisler , Handb. I. p. 199 ; and Lacordaire ,
Introduct. &c. II. p. 329. The ovaries of the
Strepsiptera are organized after a wholly different
type. The simplicity of the female organs here is
very remarkable, and in this respect they hold an
exceptional position. The two ovaries are, at first,
two long bodies, composed of innumerable germs.
When these last have matured, they are disengaged

dae, Andrenidae, Vespidae, &c., these particles
have the form of those of the Araneae — an arcuate
staff, to which is attached a delicate tail ; while,
with the Phasmidae, they consist of a spoon-shaped
head with a very conspicuous tail — indeed, quite
resembling those of many of the Rodentia. It is
scarcely necessary to add that in this class these
particles are, as is the case with all the other classes
of animals, developed in special cells. The whole
subject is deeply interesting, in both a histological
as well as a zoological point of view. — Ed.

450

THE INSECT A.

§ 349.

ovarian tubes are, moreover, always enveloped by numerous trachean net-
works.® Upon their length, which is very variable, depends the number
of the eggs or germs which are disposed in a single file ; and in this way,
they may be distinguished as uni-, bi- and multi-locular. The two Oviducts
are usually short and often dilated into a kind of calyx at their upper
extremity, if there are numerous ovarian tubes meeting at this point.

The Seminal receptacle ( Receptaculum seminis ) is a double or single,
solid capsule ( Capsula seminalis) of variable form and surrounded by a
muscular layer. It opens into the vagina below the point of junction of
the two oviducts, by means of a canal of variable length ( Ductus semi-
nalis). This duct has sometimes a simple, or a bifurcated appendage
( Glandula appendicularis).&) The seminal receptacle never contains
spermatic particles with those females which have not rejected their pupa
covering, or especially with those still in a virgin state ; but after copula-
tion it always contains a multitude of these particles moving very actively,
and these movements are kept up for a long period, as may be observed
with those females which live over the winter. (4>

The Copulatory pouch ( Bursa cojndatrix) consists nearly always, of a
spacious, pyriform reservoir, which, with oidy a few exceptions, opens into
the vagina below the seminal receptacle. During copulation, it receives
the penis, and often, also, the sperm which enters either by portions con-
tained in the spermatophores, or enveloped by a shapeless gelatinous
substance. (5)

The secretory organs situated at the lower end of the vagina, consist,
usually, of two rather long, glandular tubes on each side of the vagina,
into which they open, either directly, or through two small special excre-
tory ducts. They often have, on their course, two vesiculiform reservoirs.
In most cases, these glandular organs appear to form a Sebaceous or

and scattered through the cavity of the body be-
tween the fat-cells. The females are apodal, and
the ventral surface of their body, which resembles
that of the larvae, is occupied by a shallow canal
(Incubatory canal) which terminates caecally in
the penultimate segment of the body, and opens
upon the cephalothorax by a semilunar orifice
(Genital opening). From this canal pass off into
the visceral cavity three to five forward-bent tubes.
The eggs are developed in the visceral cavity, and
by these tubes the young larvae make their exit
therefrom ; see my Beitr. zur Naturgesch. d. wir-
bell. Thiere. p. 75, Taf. III. fig. 62,67 *, and fVieg-
mann's Arch. 1848, I. p. 147. Formerly, I erred
in taking the ventral for the dorsal surface with
these insects.

2 J. Mailer has taken these filaments for vessels
communicating between the ovaries and the dorsal
vessel •, see Nov. Act. Nat. Cur. XII. p. 580.

3 For a long time this Receptaculum seminis
remained wholly unobserved, or was taken for a
Bursa copulatrix , or an organ secreting a viscous
substance for gluing the eggs together and to for-
eign objects. The older descriptions and figures
give, therefore, only an imperfect idea It is only
lately that the constant presence and true nature
of this organ have been recognized (see my memoir
in Muller's Arch. 1837, p. 392, and Stein , Vergl.
Anat. &c. 1847, p. 96). Yet, at this day, the cop-
ulatory pouch and seminal receptacle are frequently
confounded together ; and L. Dufour, in particu-
lar. persists in his old error in designating this sem-
inal receptacle as a Glande sebifique.

4 See my observations made upon Vespa ( IVieg -
mann's Arch. 1839, I. p. 107) and Culex ( [Ger -

mar's Zeitsch. II. 1840, p. 442). Stein , also (loc.
cit. p. 112), has shown that the spermatic particles
remain alive a long time in the seminal receptacles
of the Coleoptera. The liquid secreted by the
accessory gland serves, probably, to keep the
spermatic particles fresh, and to prevent them from
desiccation. The fecundation takes place undoubt-
edly when the eggs pass in front of the orifice of
the seminal receptacle, which is then probably com-
pressed by an investing muscular apparatus. This
long preservation of sperm in the seminal receptacle
explains how the females of certain species can lay
eggs so long after copulation, and at a time when
the males have all disappeared. The time of the
full maturity of the eggs in the ovary, moreover,
does not always coincide with that of the heat and
copulation with the male. The observations which
have been made on this last point have been col-
lected by Muller (Nov. Act. Nat. Cur. XII. p. 624).

b This copulatory pouch, which, from its large
size, was first perceived by entomologists, is even
now often taken for a fecundating sac, or a seminal
reservoir {Sperm at heca). The spermatic particles
are carried, undoubtedly by their own move-
ments, from this copulatory pouch into the Re-
ceptaculum seminis ; and very probably they
begin to travel shortly after copulation, for, a long
sojourn in the Bursa copulatrix does not ap-
pear advantageous, since those that remain over
become stiff and dead-like in the midst of the semi-
nal fluid, which is granulous and viscid. J. Hun-
ter (Philos. Trans. 1774), in his experiments on
artificial fecundation, was successful only when he
took the sperm from the copulatory pouch of the
females which had just come from copulation.

§ 350.

THE INSECTA.

451

Mucous apparatus (Glandulae sebaceae or colleteriae ), for they secrete a
viscous, coagulable substance, which serves to envelop and glue the eggs
together, and to fix them to foreign bodies. With the females of the
Ichneumon idae, this apparatus secretes a kind of cement with which these
insects close the wounds they have made in the bodies of the Insecta in
which they have deposited their eggs. It is probable, also, that, with those
Insecta which deposit their eggs by means of an ovipositor in the tissues of
plants, thereby producing galls, these same organs serve as a kind of
Poison-apparatus causing this diseased formation of the vegetable paren-
chyma.

§ 350.

The different parts of the female genital apparatus present, in the vari-
ous orders and families, countless modifications as to number, form and
disposition. The most important of these are the following :

With the Aptera, the two ovaries consist each of only four to five tubes,
which, with the Pediculidae, open, all, at the top of the corresponding
oviduct ; while with the Lepismidae, they are separately inserted on the
side of the moderately long oviduct. In both of these families, there are two
short varicose caeca, which enter laterally the lower end of the vagina, and
are probably sebaceous or viscous organs. (1> There appears to be here no
seminal receptacle or copulatory pouch.

With the Hemiptera, the ovaries consist ofafour to eight tubes of variable
length, disposed verticillate at the extremity of the short oviducts. The
Psyllidae and Oicadidae, alone, form an exception in this respect. With
the first, the ovaries are composed of ten to thirty unilocular tubes, and
with the second, twenty to seventy bilocular ones. These last, moreover,
are distinguished by their oviducts being divided into several branches, on
the extremity of each of which is a tuft of ovarian tubes.® Their Recep-
taculum seminis consists of two small caeca.® The other Hemiptera have
only a single seminal receptacle, which is pyriform with the Psyllidae and
oviparous Aphididae ;(4) is a long, slightly flexuous caecum with the Naucor-
idae, and Nepidae; and a very long, somewhat llexuous caecum with the
Hydrometridae. With many Capsidae, and other Geocorisae, also, it is a
pretty long and flexuous caecum, while, with the Pentatomidae, the rather
short D actus semi nails terminates in a brownish, horny, pyriform Capsula
seminalis, the constrictions and protuberances of which often present a
peculiar appearance. Sometimes this tube is dilated into a second
vesicle, at whose base is a horny tube containing a second tube which
is a direct prolongation of the Capsula seminis .<5) Most Hemiptera have
no copulatory pouch, — the Cicadidae, alone, having one which consists
of a narrow-necked, pyriform vesicle.® With the oviparous Aphididae,

1 See S tvammerdamm , Bib. der Nat. p. 37, Taf. of the oviparous and viviparous Aphididae, iu
II. fig. 8 ( Pediculus ), and Treviranus , Venn. Froriep's neue Notiz. XII. p. 308.

Schrift. II. p. 15, Taf. III. fig. 8, 9 ( Lepisma ). *r> For the seminal receptacle of the Pentatomidae,

2 See L. 1) uf our , Recherch. sur les Ilemipt. PI. see L. Dufour , Recherch. &c. loc. cit. PI. XIV.J
XIV.-XVII., and Ann. d. Sc. Nat. Y. 1825, p. 168, XVI., and Siebold , in Muller's Arch. 1837, p.
PI. IV. (Cicada); and Suckow , in Heusinger's 410, Taf. XX. fig. 4-6.*

Zeitsch. II. Taf. XV. fig. 55,57 (Nepa and Cercopis ). 0 See Meckel and L. Dufour , loc. cit. Accord-

3 See Meckel, Beitr. &c. I. lift. I. Taf. I. fig. 6, i. ing to Doyfre (loc. cit. p. 203, PI. VIII. fig. 3).
I.; Tj. Dufour , Ann. d. Sc. Nat. V. 1825, PI. IV. fig. there is, with the female Cicadidae, a special orifice
5 |. 1., a, nd fig. 8, d. d. ; and Doyire, Ibid. VII. by the side of the oviduct, which is continuous with
1837, Pi. VIII. fig. 3-7, e. e (Ledra and Cicada). the ovipositor, and through which the penis pro-

•l S-'j my memoir on the internal genital organs trades into the copulatory pouch.

* [ § 350, note 5.] For the female organs of Belostoma , see Leidy , loc. cit. p. 64. — Ed.

452

THE INSECTA.

§ 350.

and many Geocoripae, the secretory apparatus consists of two round gland-
ular sacs,(7> while, with the Cicadidae, it is a single, long flexuous tube.®
The viviparous Aphididae differ from those which are oviparous, in that
their eight ovarian tubes are multilocular, and their oviducts entirely with-
out, appendages ; while with the second or oviparous, these eight tubes are
unilocular, and there is a- seminal receptacle and two sebaceous glands.®

With the Diptera,110' the ovaries consist, usually, of numerous short,
three or four chambered tubes. With only a few species, these tubes are
long and have eighteen to twenty chambers. (11) The disposition of these
tubes varies considerably. With some, they are simply terminal to the
short oviduct ; while with others they form one or more series on the
sides of these organs, which, then, are longer.

The Receipt aculum seminis presents the most varied forms, n2) it is usu-
ally, triple, rarely simple or double, (13> and is lined with a horny, brown
substance. It has a round, pyriform, or oblong shape, and, in this last
case, is often flexuous or spiral. The seminal ducts, which lead from
the receptacles to the vagina, are sometimes isolated, and sometimes united
into one or two common ducts before entering the vagina. Directly below
them on each side, are the points of junction of the two secretory organs,
which, always present with the Diptera, consist of two simple, rarely
ramose tubes, whose very small excretory ducts have, exceptionally only, a
vesiculiform dilatation. (14) The Bursa copula trix appears to be wanting with
all the Diptera. But, with many Muscidae, the vagina has, as a seminal
receptacle or uterus, a spacious, and sometimes two-lobed reservoir in which
the fecundated eggs are accumulated in great numbers, and remain until the
larvae are sufficiently developed to be hatched, making these animals vivi-
parous.(15) With certain species of Tachina, this uterus presents a remark-
able form ; the vagina is very long, spiral, arid of equal size throughout ;
and, at certain periods, is crowded with larvae or small eggs.(16> With the
pupiparous Hippoboscidae, the female organs are formed on an entirely
special type, corresponding with the remarkable mode of the reproduction

7 See L. Dufour , Recherch. loc. cit. PI. XIV.
XV.

8 See Meckel , Suckow , L. Dufour , Doy&re ,
loc. cit.

9 See my researches in Froriep's neue Notiz.
XII. p. 307. Dutrochet (Ann. d. Sc. Nat. XXX.
1833, p. 204, PI. XVII. C. fig. 1), it would appear,
has unwittingly figured the genital organs of an
oviparous Aphis , by taking the seminal receptacle
for a sperm-secreting organ. In this way he was
led to regard the viviparous Aphididae as her-
maphrodites.

10 For the internal female organs of the Diptera,
see L. Dufour , Ann. d. Sc. Nat. I. 1844, p. 253,
and especially Loew , Horae anatom, p. 61.

H Ephydra and Tachina; see Loew, loc. cit.
Taf. IV. tig. 3, 10.

12 For the Receptaculum seminis of the Dip-
tera, see Siebold , in Muller's Arch. 1837, p. 414,
Taf. XX. fig. 7-10 5 and especially Loew, loc. cit.
p. 89, Taf. IV.-VI., and in Germar's Zeitsch. III.
p. 386, Taf. III.; the numerous figures of this
author will give some idea of the inexhaustible va-
riety of forms of these organs. When L. Dufour
(Ann. d. Sc. Nat. 1. 1844, p. 262) would regard the
seminal receptacle as a reservoir of the neighboring
secretory organs, it is evident that this distinguished
entomotomist must have entirely omitted a micro-
scopical analysis of the substances found in the
various glands and other organs of Insecta.

13 The Receptaculum seminis is simple with
Pulex , Empis , Dolichopus, and Hilara ; and
double with Piophila, Stomoxys and Borborus.

14 See Siebold , and Loew , loc. cit. These gland-
ular appendages secrete with certain Tipulidae a
considerable quantity of gelatinous substance which
envelops the eggs and binds them in a kind of col-
lar. These collars, which are deposited in the
water, have for a long time been figured by bot-
anists among the algae under the name of Gloeo-
nema.

15 There are viviparous species in the genera
Musca, Anthomyia , Sarcophaga, Tachina,
Dexia, Miltogramma, &c. ; see my memoir in
Froriep's neue Notiz. III. p. 337, and in fVieg-
mann's Arch. 1838, I. p. 197 ; also my Observat.
quaed. Entom. &c. p. 18. L. Dufour (Ann. d. Sc.
Nat. I. 1844, p. 261) has designated this reservoir
as Reservoir ovolarvigire ; see also his Hist. d.
Metamorph. et d. l’Anat. d. la Piophila petasionis.
Ibid. p. 382, PI. XVI. fig. 16, g. Loew (Horae
anatom. Tab. IV. fig. 9, 11, 14, Tab. V. fig. 13)
has figured analogous uteriform reservoirs with
Musca, Dexia, Piophila and Psila.

10 This long spiral-form vagina, which was for-
merly described as an ovarium spirale , is found in
Tachina fera, tessellata, grossa, vulpina, hae-
morrhoidalis, &c.; see my memoir in IVieg-
mann's Arch. loc. cit. p. 194, and Reaumur,
Mem. IV. 10 m£m. p. 412, PI. XXIX. fig. 7, 8.

§ 350.

THE INSECTA.

453

of these animals. The two ovaries are unilocular pouches of unequal size,
inserted laterally, by means of a short oviduct, upon the vagina. The upper
extremity of this vagina contains sperm, after copulation, and may, therefore,
be regarded as a Receptaculum seminis ; while the lower portion is wide-
ly dilated, and may, therefore, be considered as an uterus. The upper or nar-
rower portion of the vagina receives two small, simple, or somewhat ramose
glandular tubes ( Glandulae sebaceae) ,(17> Below these glands are situated

the two excretory ducts of a double glandular apparatus, very voluminous
and multiramose, whose product serves, without doubt, to nourish the
larvae which are provisionally developed in the uterus. (18>

With the Lepidoptera, each ovary is composed of four very long, spiral,
multilocular tubes. The Receptaculum seminis (19) is pyriform, and often
has a long, spiral Ductus seminalis.m At its base opens a simple or bifur-
cated accessory gland, and underneath it there is always a large, double,
sebaceous gland, consisting of two rather long, flexuous, simple caeca.
These last open into the vagina, by means of a short common excretory
duct, and each, at their point of union, is usually dilated into a vesiculi-
form reservoir. <21) Some Lepidoptera have, moreover, two smaller ramose
glands, situated near the orifice of the vagina, which secrete, perhaps, an odor-
ous substance that excites the copulatory act.(2i!) The copulatory pouch,
finally, is very remarkable in all the species of this order. It consists of a
large, pyriform reservoir, sometimes constricted in its middle, and hav-
ing for the reception of the penis, a canal which opens externally by a
special orifice situated below the vulva. In its course this canal sends
off' a small, flexuous, lateral duct, which passes into the vagina opposite the
mouth of the Receptaculum seminis , and thus forms a communication
between this last and the copulatory pouch. (33)

With the Hymenoptera, the ovaries(24) vary very much as to the number
of their component tubes, of which there are sometimes four to six, some-
times eight to ten, and with some species they range from twenty to a hun-
dred. (23) These 'tubes are always multilocular, and never very long. The

ir These tubes are simple with Melophagus , and
ramose with Hippobosca.

IS See my researches in Muller'1 s Arch. 1837, p.
425, and those of L. Dufour , Ann. d. Sc. Nat. VI.
1825, p. 303, PI. XIII., and III. 1845, p. 76, PI. III.
This last-mentioned naturalist has very well figured
the female organs of Hippobosca and Melophagus ;
only he is deceived relative to the glandular append-
ages of the vagina, in regarding the upper pair as
a Receptaculum seminis , but which never contain
spermatic particles.

10 For the appendages of the female organs of the
Lepidoptera, see Siebold , in Muller's Arch. 1837,
p. 417.

20 The seminal receptacle has been figured in its
various stages of development by Herold (Ent-
wickelungsgesch. d. Schmetterl. Taf. IV. fig. 1, u. y.
p. and Taf. XXV.) as a unicornous secreting organ.
See also Suckow , Anat. u. physiol. Untersuch.
Taf. VI. g. g.

21 See Herold , loc. cit. Taf. III. fig. 1, t. z.
and the following plates } also Suckow , loc. cit.
Taf. VI. 1. 1.

22 Melitaea , Argynnis , Zygaena) &c.

23 See Herold , loc. cit. Taf. III. fig. 1, x. f. g.
and the plates following} also Suckow , loc. cit.

* [ § 350, note 23.] See also for the internal
female genital organs, and especially their develop-
ment, of the Lepidoptera, Meyer , loc. cit. Siebold

Taf. VI. K. (indistinct). Moreover, Malpighi (De
Bombyce, 1660, p. 81, Tab. XII. fig. 1, J. K. M.)
had already perceived, with the silk-worm, all the
appendages of the vagina, and specially the copu-
latory pouch with its canal of lateral communica-
tion. With Euprepia Hebe this canal has a pyri-
form deverticulum.*

24 For the female genital organs of the Hymen-
optera, see L. Dufour , Recherch. sur les Orthopt.
&c. p. 406.

25 Each ovary is composed of three or four ovige-
rous tubes with Xylocopa , Bombus , Arithophora ,
Chrysis ; of five to six with Nomada , Sapyga ,
Chalcis , Vespa ; of eight to ten with Pimpla , Pa-
niscus ; of ten to twelve with the Tenthredinidae ;
of twenty to twenty-five with Myrmica , Xiphrydria
and Banchus ; and of more than one hundred with
Apis. With Chelonus the ovaries present a re-
markable exception ; they consist each of two long
flexuous tubes, which are very widely dilated at
their lower extremity. L. Dufour (loc. cit. p.
541, PI. X. fig. 143) regards these swellings as a
kind of uterus in which are developed the larvae of
these Ichneumonidae } but this assertion cannot be
admitted without further research.

and Kolliker's Zeitsch. I. 1849, p. 182. This
memoir contains many new details. — Ed.

454

THE INSECTA.

§ 350.

Receptacula seminis is nearly always simple, round, or ovoid, and necked,
and is continuous into a usually short, seminal duct.(2G> A Glandula appen-
dicularis is never absent, and consists, usually, of a bifurcate tube, which
opens into the Ductus seminalis, and only rarely into the Capsula seminalis
itself. <27)

With the Tenthredinidae this apparatus is, moreover, formed after a dif-
ferent type ; the seminal vesicle is a simple deverticulum of the vagina, and
more or less distinct from it, beside, it is deficient in the accessory gland. (28>
The copulatory pouch is absent with all the Hymenoptera, as are also the
Glandulae sebaceae with those females which have a sting and a poison-
gland ; but these sebaceous glands are highly developed with those species
having an ovipositor, into which last they open, and probably serve some
purpose connected with the oviposition, partly as sebaceous, and partly as
excitatory organs. This secretory apparatus consists of a simple or a
double ramose gland, whose excretory duct receives the neck of a pyriform
receptacle, or, sometimes, is itself dilated into a vesicular reservoir. (29)

With the Orthoptera, the two ovaries are nearly always composed of nu-
merous, multilocular tubes, which usually open in a single row upon the inter-
nal or external side of two large and sometimes very long ovaries. (30) The
seminal receptacle often consists of a simple longer or shorter pedunculated
vesicle, whose closed extremity is dilated into a pyriform vesicle with the
Psocidae, Forficulidae, Locustidae, Phasmidae and Mantidae.<31) A similar
Capsula seminis is often found with the Acrididae on one of the sides of the
Ductus seminalis and removed from its extremity. <32) Most of the Blat-

26 For the Receptaculum seminis see Siebold ,
Observ. quaed. Entora. loc. cit. p. 6, and in Ger-
mans Zeitsch. IV. p. 362, Taf. II. With those
females which, at short intervals, lay very many
eggs, the seminal receptacle is very large ; see
Swammerdamm , Bib. der Nat. Taf. XIX. fig. 3,
t. u. u., where the Receptaculum seminis of a
honey-bee is very well represented.*

27 The Glandula appendicular is is simple and
inserted on the Ductus seminalis with the Ptero-
malini and Cynipidae •, it is double, and opens
lirectly into the Capsula seminis , with Vespa
:rabo and Tiphia femorata.

26 The seminal receptacle is double, exceptionally,
vith Lyda.

29 This glandular apparatus is simple and has a
ateral pyriform reservoir with various Ichneumon-
idae ; see L. Dufour , Recherch. PI. X. fig. 137-
142 ( Pimpla and Bracon). This naturalist calls
this apparatus Glande sirifique, as distinguishing
it from the Glande stbifique. With Sir ex , I have
observed the excretory duct of this single and mul-
tiramose gland dilated into a large reservoir. With
the Tenthredinidae, it is also ramose, but double as
well as its vesicular reservoir *, see L. Dufour , loc.
cit. PI. X. fig. 155-157 ( Tenthredo and Cimbex).

30 With the Locustidae, Acrididae, Mantidae
and Libellulidae, the ovarian tubes are inserted
upon the internal side, and with the Phasmidae
and Ephemeridae, on the outer side of the two ovi-
ducts. Forficula gigantea has, moreover, only
five internal multilocular tubes, while with Forji-
cula auricularis, the very long oviducts have on
all sides a multitude of unilocular tubes. With
Mantis , the ovarian tubes are unilateral, but
united together in several bundles. With Oedi-
poda cerulescens and Truxalis nasuta , the two

* [ § 350, note 26.] See also Longstreth (Proc.
Acad. Sc. Philad. 1852, VI. p. 49) for some observa-

long, flexuous, caecal oviducts, have tubes only at
their lower extremity. The oviducts of Perla bi-
caudata are still more remarkable ; they are very
long, flexuous, and have ovarian tubes only on one
side of their upper extremity, and anastomose in a
loop-like manner. For all these differences, see L.
Dufour , Recherch. sur les Orthopt. kc. PI. II.-
V. and PI. XI. fig. 165, PI. XIII. fig. 206, and
in the Ann. d. Sc. Nat. XIII. 1828, PI. XXI. XXII.
( Forficula ).

31 With Forfcula, and Acheta , the seminal re-
ceptacle has a long and flexuous peduncle, which,
with the Psocidae, and Locustidae, is shorter. That
of Psocus pulsatorius contains several long-pe-
dunculated, glandular bodies ( Nitzsch in Ger-
mans Magaz. IV. p. 281, Taf. II. fig. 3-5), which
I formerly regarded as Capsulae seminales
( Muller's Arch. 1837, p. 410), but which are prob-
ably spermatophores. With Perla , the seminal
receptacle is a simple caecum, twisted like a ram’s
horn, and the base of which supports several short
glandular follicles ( Glandulae appendicu lares ?).
For the seminal receptacle of the Orthoptera cited
in the text, see especially Roesel, Insektenb. Th.
II. Heuschrecken-und Grillen Sammlung. Taf. IX.
fig. 3, k. (Decticus) ; L. Dufour , Recherch. sur
les Orthopt. PI. III. fig. 31, PI. IV. fig. 43 ( Acheta
and Mantis ); and Siebold , Nov. Act. Nat. Cur.
XXI. part I. p. 254, Tab. XIV. fig. 1, c. (Lo-
cust a).

32 See Hegetschweiler , De insect, genitalibus
dissert., fig. VII. f. e.; and Siebold , in Muller's
Arch. 1837, p. 409, Taf. XX. fig. 3 ( Gryllus ).
The Ductus seminalis is usually very long and
intertwisted, as, for example, with Gryllus , Trux-
alis, &c.

tions on the impregnation of the common honey-bee,
as due to a Receptaculum seminis. — Ed.

§ 350.

THE INSECTA.

455

tidae(33) and Libellulidae'341 have a short, double, seminal receptacle, which,
however, appears to be wholly wanting with the Ephemeridae. There is a
round Bursa copulatrix only with the Libellulidae/351 The glandular
appendages of the vagina are also not found with all the Orthoptera.
They are wanting with the Eorficulidae, Phasmidae, Perlidae, Ephemeri-
dae, Libellulidae and Acrididae, but with Declicus and Locusta, there is
a sebaceous organ consisting of a simple, pretty long tube,136' which, with
the Achetidae, is more or less ramose, and with the Blattidae and Mantidae is
composed of a considerable numberof partly simple, partlyramose follicles.'371

With the Neuroptera, the ovaries consist always of multilocular tubes.
With the Hemerobidae, and Myrmeleonidae, there are ten inserted on the
external side of the two large oviducts, and with the Phryganidae, their
number is quite large, but their insertion on the oviducts is the same.*38'
The ten with Panorpa, and the much larger number with Stalls, are dis-
posed verticillatc at the extremity of the oviducts. With Myrmeleon and
Panorpa, the seminal receptacle is a long, pedunculated sac ; and has, with
Hemerobius, a single, and with Rapkidia, a double Glandula appendicula-
ris.&3) With the Phryganidae, this receptacle is still more complicated,
for, beside a long, tortuous accessory gland, which is inserted on the neck,
or at the base of the Capsula setninis, there is, at the lower extremity of
the Ductus seminalis, another and flexuous glandular tube, and a short-
pedunculated reservoir which corresponds perhaps to a copulatory pouch. (40)
With Stalls, beside two lateral deverticula serving, probably, as copulatory
pouches, the vagina has numerous vesicular appendages filled with a dark
liquid, but the nature of these is still not understood. (41) With Myrmeleon,
Hemerobius, and Panorpa, the vagina receives two simple, more or less
flexuous, glandular tubes/421 which are probably sebaceous organs, and
with the Phryganidae, consist of six digitiform follicles. 1431

With the Coleoptera, the ovaries consist of trilocular, rarely multilocular
tubes/441 which are inserted on the calyciform upper extremity of the oviducts,
in groups of five to ten or even of fifteen to thirty and forty.'451 Beside

33 Rlatta orientalis has two short and flexuous
seminal receptacles *, but lilatta germanica has
two large and two small ones j see Siebold , in
Muller's Arch. 1837, p. 408.

34 The seminal receptacles of Libellula , Aesclina
and Diastatomma consist of two small caeca,
which, with Calopteryx , open into the vagina
through a common duct ; while, with Agrion , there
is only a single long receptacle ; see Ruthlcd, De
Libellular. partibus genital. Tab. I. fig. 11-13, Tab.
II. fig. 12-14, and Tab. III. fig. 9-11, e., and L.
D iif our , loc. cit. PI. XI. fig. 165^.d. d. ( Libellula ,
Aesclina and Agrion). See also my memoir on
the generation of the Libellulidae, in Germar's
Zeitsch. I. p. 433.

35 See Rat like, loc. cit. Tab. I. fig. 11-13, Tab.
II. fig. 12, 13, and Tab. III. fig. 9-11, b.

36 See Roesel , loc. cit. Taf. IX. fig. 3, i., and
Siebold , Nov. Act. Nat. Cur. loc. cit. p. 255, Tab.
XIV. fig. 1, e.

37 See L. Dufour , Recherch. &c. PI. III. fig.
31, d. ( Oecanthus ), PI. IV. fig. 43 {Mantis). It
is not surprising that this wax-apparatus is so
highly developed with the Blattidae and Mantidae,
for, as is known, the females of these insects sur-
round their eggs with very spacious, multilocular
capsules, which they carry about with them, or
fasten to foreign bodies ; see Gaede , Beitr. &c.
Taf. I. lig. 13, 14 ( Rlatta orientalis ), and Roesel ,
loc. cit. Th. IV. Taf. XII. {Mantis).

38 For the female organs of the Neuroptera, see
L. Dufour , Recherch. sur les Orthopt. &c. PI.
XII. XIII.

39 L. Dufour , loc. cit. PI. XII. fig. 174, d.
{Panorpa).

40 L. Dufour , Ibid. PI. XIII. fig. 211, 212.

41 L. Dufour , Ibid. PI. XII. fig. 1SS, b. •, and
Suckow , in Heusinger's Zeitsch. II. Taf. XVI.
fig. 16, d.

42 L. Dufour , Ibid. PI. XII. fig. 174, 194, c. c.

43 L. Dufour , Ibid. PI. XIII. fig. 211. By
means of these glands the females of Phryganca
envelop their eggs with a gelatinous substance
which swells in water and often sticks to stones or
aquatic plants, presenting the appearance of an
annular spawn.

4-1 The ovarian tubes are multilocular with the
Carabidae, Hydrocanthari, Cyphonidae, Telephori-
dae, and Curculionidae *, in general they are
bilocular with the Staphylinidae 5 see Stein ,
Vergl. Anat. &c. p. 29.

45 The ovaries are multitubular with the Cara-
bidae, Hydrocanthari, Hydrophilidae, Elateridae,
Chrysomelidae,and Coccinellidae’, while with Apio/i,
Lixus, and Hylcsinus , there are only two on each
side ; see L. Dufour , Ann. d Sc. Nat. VI. 1825, PI.
XVII. -XX. 5 Suckou >, in Heusinger's Zeitsch. II.
Taf. XIII., and Stein, loc. cit. Taf. III.-VIII.

456

THE INSECTA.

§ 350.

these fasciculate, there are, also, here and there, botryoidal ovaries, in which
there are numerous imbricated tubes inserted on a large calyx of each of
the oviducts. <4S) When these tubes are few in number, they are but rarely e
disposed in simple or double regular series. (47) With most species, the
Receptaculuvi seminis is cuneiform and often arcuate ; its internal walls
are brown, solid and horny, and it communicates with the vagina or copu-
late ry pouch by means of a long, fiexuous, spiral Ductus seminalis. With
many species, this receptacle is invested with a muscular apparatus, com-
posed of striated fibres, and which undoubtedly is a compressor. Usually,
there is, attached to the base of the receptacle, a simple, rarely bifurcate
or multiramose, Glandula appendicular is, which is sometimes provided with
a long, fiexuous excretory duct.(4Sl Sometimes the entire Recept aculum
seminis is composed of only a simple, rarely bifurcate, somewhat long cae-
cum. m Most of the Ilydrocanthari, and some Carabidae, with which the
Ductus seminalis is inserted on the copulatory pouch, have the peculiarity
that there arises from the Receptaculuvi seminis a special Fecundatory
canal which opens into the upper portion of the vagina. (S0) A Bursa
copulatrix exists, generally, in this order. With only a few species, it
consists of a simple dilatation of the vagina, (S1) but, usually, it is a rather
long, muscular caecum, separated from the upper wall of the vagina, and
sometimes even fiexuous when its length is considerable. (53) Very often,
the vagina is quite long, curved S-shaped, and passes with the rectum into
a cloaca-like canal. It has a complicated special muscular apparatus. (53)

The glandular appendages of the vagina are wanting with the Ooleoptera,
but, with the Ilydrophilidae, there are two multiramose appendages on the
oviducts, which are probably sebaceous organs. (54) The same function may,
perhaps, be attributed to the glandular walls of the upper extremity of the
oviducts of the Staphyliuidae and IIisteridae.(55)

46 With the Melo'idae ; see Brandt and Ratze-
burg , Mediz. Zool. II. Taf. XVII. fig. 2.

47 The ovaries are in single ro vs with Macrony-
chus , Oxytelus , Silpha , and Byrrhus ; but they
are in two rows with Stenetmis , Lycus , Oedeme-
ra , and Hydrobius ; see L. Du four, Ann. d. Sc.
Nat. III. 1835, PI. VII. fig. 25, 27 ; and Stein ,
loc. cit. Taf. III. fig. 3, 16, Taf. IV. fig. 3, 4, and
Taf. VI. fig. 8. There is a very remarkable dispo-
sition, according to Stein (loc. cit. p. 30, Taf. I.
fig. 4), with Dianous caerulescens, Myrmedonia
caniculata , Homalota canaliculata , and a spe-
cies of Trichopteryx , which, alone among all
known Insecta, have only a single ovary and a
single oviduct, the first being composed of ten to
twelve tubes disposed in two rows.

48 For the different forms of the Receptaculum
seminis of the Coleoptera, see L. Dufour , Ann. d.
Sc. Nat. VI. 1825, and III. 1835, &c. •, Siebold, in
Muller's Arch. 1837, p. 404, Taf. XX. fig. 1, and
especially Stein , loc. cit. p. 96, with the corre-
sponding figures. With the Elateridae, the acces-
sory gland is distinguished by a very complicated
structure and numerous ramifications ; see L. Du-
four, Ann. d. Sc. Nat. VI. 1825, PI. XVII. fig.
8-10, and Stein, loc. cit. p. 129, Taf. V. The sem-
inal receptacle is wholly wanting with Xantholi-
nus punctatus , Lathridius porcatus, Notoxus
monoceros , and Lagria hirta ; see Stein, loc.
cit. p. 93.

4I> With the Carabidae, and some Staphylinidae.
The seminal receptacle is double with Stenus and
Paederus ; see Stein, loc. cit. p. 97, Taf. I. III.
fig. 6.

50 With the Ilydrocanthari and some Cara-

bidae ; see Stein, loc. cit. p. 99, Taf. I. fig. 12,
Taf. II.

51 Silpha, Dromius, Calosoma , and other Cara-
bidae.

52 See Straus, Consid. &c. PI. VI. fig. 2, o. n.
( Melolontha ) ; Brandt and Ratzebur g , Mediz.
Zool. II. Taf. XVII. fig. 2, n. m. ( Meloe ) ; Suclc-
ow, in Heusinger's Zeitsch. II. Taf. XIII. -, Sie-
bold, in Muller's Arch. 1837, p. 405, but especially
Stein, loc. cit. p. 69, and the corresponding
figures.

5-3 There is a long, fiexuous, muscular vagina
with the Cerambycidae, Curculionidae, Elateridae,
Uuprestidae, and most of the Ileteromera ; also,
with the Ilisteridae, Dermestidae, Parnidae, &c.;
see Stein's exact descriptions, loc. cit. p. 71, Taf.
VI.-VIII.

54 See Stein,^ oc. cit. p. 33, Taf. IV. fig. 3
( Hydrobius fuscipes). With Hydrobius piceus,
and caraboides, there are even two kinds of anal-
ogous appendages. One consists of eight bifurcate
follicles, the other of simple tubes inserted on the
calyx of the oviducts ; see L. Dufour, Ann. d.
Sc. Nat. VI. 1825, p.445, PI. XVIII. fig. 5, and
Suckow , in Heusinger's Zeitsch. II. Taf. XIII.
fig. 34. The bifurcated appendages were over-
looked by this last naturalist. It is well known
that the females of the Ilydrophilidae enclose their
eggs by groups in a cocoon ( Lyonet , M£m. du
Mus. &c. XVIII. p. 454, PI. XXIV.) which those
of Spercheus carry about attached to' their poste-
rior legs.

55 Stein , loc. cit. p. 35.

§ 351.

THE INSECTA.

457

§ 351.

The External Genital Organs of the females are pretty simple with the Ap-
tera, Hemiptera, Lepidoptera, Coleoptera, with many of the Diptera, Orthop-
tera, and Neuroptera, and with some Hymenoptera. The orifice of the vagina
is supported by an upper, and two lateral horny plates, whose size and form
vary according to the species. With only some Coleoptera, Diptera, and
Hymenoptera, the end of' the vagina is protractile, appearing as a more or
less articulated Vagina tubiformis ,(1) These horny plates about the

vaginal orifice serve to support the penis during copulation, and to facilitate
the escape of the eggs during oviposition.(2) With the Acrididae, these
plates are conical, and in two pairs, one upper, and one under, which
may be opened and shut in a pincer-like manner. With several genera of
the Tipulidae, and Asilidae, the two lateral plates are very long, and form
a simple ovipositor (Vagina bivalvis) .(3) 4 With Boreus, and Acheta , this

ovipositor is long, and with Raphidia , it is long and acinaciform. The
Locustidae have also a similar and very prominent ovipositous sabre, but
more complicated in that each of its plates is divided into three pieces,
which are so disposed that the two internal, soft, are surrounded in a sheath-
like manner by the four others, which are horny. With the Tenthredini-
dae, and with Aeschna , Agrion, and Calopteryx, there is an analogous
apparatus situated at the posterior extremity of the abdomen, and covered
by two valves, only that its pieces are denticulated in a saw-like manner,
and therefore is called saw-ovipositor. (4> With the Siricidae, the ovi-
positing apparatus is likewise composed of two horny, denticulate plates ;
but is more auger-like in its form, and, with some species, projects far
beyond the short lateral valves.®

The Ichneumon idae, Cynipidae, and Cicadidae have a more or less long
ovipositor ( Terebra ), composed of two lateral groove-like sheaths, between
which plays a kind of sting composed of two intimately-united horny
shafts. This sting serves, partly to pierce the substance in which the eggs
are to be deposited, and partly to push the eggs along the sheath formed
by the groove-like valves.® All these different ovipositors have a muscu-
lar apparatus at their base, by which their component pieces are moved.

With some Libellulidae, there is a peculiar groove-like appendage on the
penultimate abdominal segment. It serves to receive the eggs at the

1 The ovipositor is unarticulated and protractile
with the Cerambycidae, while it is articulated with
the Chrysididae and many of the Muscidae. In this
last case, its pieces are movable, like the tubes of a
telescope. They are only the terminal abdominal
segments modified ; see L. Du, four , Ann. d. Sc.
Nat. I. 1844, p. 383, PI. XVI. fig. 16 ( Piophila ).

2 For the ovipositor of Insecta, see Burmeister ,
Handb. &c. I. p. 209, Taf. XII., and Lacordaire ,
Iutroduct. &c. II. p. 353.

3 Limnobia, Pti/choptera , Tipula , Ctenopho-
ra , AsiLus , Lapkria. Among these Diptera,
Ctenophora rujicornis is particularly distinguished
by the length of the horny plates composing the
ovipositor.

4 For the structure of this saw-like ovipositor,
see Lyonet, Mem. du Mus. XIX. p. 57, PI. VI.-
VIII. (14-16) (Mouches 5 scie) ; and Hartig , Die
Adlerfliigler Deutschl. p. 37, Taf. I. u. d. f. ; also,
Reaumur, M£m. VI. 11 memoire, PI. XL. fig. 6-

39

9 {Agrion). It is well known that these Insecta
use this ovipositor to pierce the epidermis of
plants, and to introduce therein their eggs. The
deposition of the eggs with the Tenth redinidae
has been described with details by Dahlbom (Isis,
1837, p. 76) and by Ratzeburg (Forstinsekten,
Th. III. p. 65). I have, also, observed this act with
Agrion forcipula {JViegmamV s Arch. 1841, I. p.
205).

5 Hartig and Ratzeburg have given a detailed
description of the auger of the Siricidae ; it is par-
ticularly long with Xiphydria and Sir ex.

6 For the ovipositor of the Hymenoptera, see
Hartig , Die Adlerfliiger Deutschl. p. 16 •, in
Wiegmann's Archiv, 1837, I. p. 151, and in
Germans Zeitsch. III. p. 326 5 Ratzeburg , Me-
dia. Zool. II. p. 145, Taf. XXIII. ( Cynips ). For
that of the Cicadidae, see Reaumur, Mem. V.
4 memoire, PI. XVIII. j and Doytrc, Ann. d. Sc.
Nat. VII. 1837, p. 193.

458

THE INSECTA.

§§ 852, 353.

moment of their escape from the vagina, and in this way the eggs a^e col-
lected in masses to be deposited in places fit for their incubation.

II. Male Genital Organs.

§ 352.

The Testicles, which are double like the ovaries, consist, sometimes of
two simple caeca, which are more or less long and torose, and sometimes
of many caeca, very variable as to their forms and disposition. Their
mode of grouping resembles that of the ovaries ; indeed, their whole
appearance and contour, and the number and composition of their various
parts resemble remarkably those of the female organs. With many spe-
cies, these organs are covered by a lively-colored pigment layer, or envel-
oped by a special membrane (Tunica vaginalis).

The*two Vasa deferentia are of variable length, often exceeding that of
the body, and therefore making several convolutions in the abdominal cav-
ity. When the testicles are composed of many caeca, there are often the
same number of these canals; but they often unite, on each side, into a
common duct. Sometimes they have, each, at their lower extremity, a
vesicular dilatation which may be regarded as a Vesicula seminalis. At
their point of junction on the Ductus ejaculatorius, there are usually situ-
ated two, longer or shorter, simple Glandulae mucosae, which secrete a
quickly coagulating, granular mucus, which serves, during the copulatory
act, partly to fill and distend the Bursa copulatrix together with the
penis, and partly to surround portions of the sperm, and thereby form
spermatophores. (1)

§ 353.

The principal modifications observed with the internal male organs of
the Insecta, are the following.

Among the Aptera, Lcpisma is distinguished in having numerous oval,
testicular follicles, whose Vasa deferentia , after forming irregular ramifica-
tions, unite in two common excretory ducts, which, gradually enlarging,
terminate in a Ductus ejaculatorius at the point of insertion of two arcu-
ate accessory glands. (1)

With the Hemiptera, the internal genital organs are of very variable
form.(2) The Pentatomidae have only two simple, pyriform testicles, often
of a beautiful red color; at their free extremity they sometimes have
several constrictions, and thus form the passage to the form proper to
many Geocorisae, which have seven long testicular tubes united in a fan-like

l The ovigerous groove is short and triangular
with Libellula vulgata and cancellata ; long,
acumiuate, and^pcrpendicular with Cordu/ia me -
tal'.ica ; long and cordately emarginate and closely
applied against the abdomen with Epitkeca bimac-
ulata. A remarkable appendage, deeply exca-

vated, situated to the exterior of the female genital
organs of Doritis Apollo and mnemosyne , and
upon which, as yet, no lepidopterist has given any
details, is probably an ovigerous sac.

1 For the various forms of the simple and com-
pound testicles, as welias for the male organs of the
Insecta in general, see Burmeister , Handb. &c.
I. p. 217, and Lacordaire , Introduct. &c. II. p.
305.

1 See Treviranus , Verm. Schrift. II. p. 15, Taf.
IV. fig. 2. The Pediculidae have only two pairs
of testicles.

2 See L. Dufour , Recherch. sur les n^mipt. PI.

x.-xm.

r

§ 353.

THE IXSECTA.

459

manner.® Sometimes these seven tubes are grouped into a bundle at the
upper extremity of each of the two deferent canals.® With the Cicadidae,
the testicular tubes are extremely numerous and fasciculate in the same
manner ;® while with Psylla, there are only four, and with Aphis, only three
on each side.® The Hydrometridae have only two or four long testicular
follicles, on the sides of which arise the deferent canals. With Pelogonus,
and Notonecta, there are two pairs of long, spiral tubes, while with Nepa,
and Ranatra, there are five on each side, long and flexuous. The Vasa
defer entia are short with most of the Geocorisae, the Psyllidae and the
Aphididae; but with the Hydrocorisae, and the Cicadidae, they are long
and intertwisted. The glandular appendages are highly developed with
most Hemiptera and often open into the two deferent canals above the
Ductus ejaculatorius.''3 4 5 * 7 8 9'1 But when these glands appear to be wanting, the
deferent canals have upon their course, or at their extremity, vesicular dila-
tations which, perhaps, take their place.® With the Pentatomidae, the
glandular appendages consist of two to four multiramose fasciculate tubes.
The Ductus ejaculatorius is then dilated at its base into a kind of vesicle
divided into two or three lobes, which serve probably as mucous reser-
voirs.00

With the Diptera, the male organs are much more simple, there never
being but two simple testicles,1® whose external envelope is often brown or
yellow. These organs are usually pyriform or oval, but sometimes long
or hooked or twisted in various ways.(11) The Vasa deferentia are usually
of considerable length/121 and open in the upper end of the Ductus ejacu-
latorius, (13) always in common with two simple and pretty long accessory
glands.

With the Lepidoptera, the testicles are always composed of two round
or oval follicles, often surrounded by a beautifully colored pigment/141 Very
often, also, they are so approximated on the median line of the abdomen,
as to appear fused into a single round body/151 The two deferent canals,
after a short course, unite with two simple, long and very flexuous acces-
sory glands, and then form a very long and torose Ductus ejacula-
torius .<I0)

3 Coreus , Alijdus , Pyrrhocoris , Acanthia.

4 Capsut r, Miris. Aradus.

5 L. Du. four, Ann. d. Sc. Nat. V. 1825, PI. VI. fig.
G, 7, and in his Recherch. sur les H&nipt. PI. XIII.
fig. 152-155 ( Cicada , Aphrophora , and Issus).

<> With Aphis Ionic erae , the six testicular tubes
are concentrated on the median line of the abdom-
inal cavity, so that they might easily be taken for a
single body •, see my observations in Froriep's
neue Notiz. XII. p. 307. According to Morren's
description (Ann. d. Sc. Nat. 1836, p. 87, PI. VI.),
there would appear to be a real fusion of the testi-
cular tubes with Aphis per sicae.

7 With Aradrus , Nepa, Cicada, Aphrophora, the
two simple glandular appendages, which are extra-
ordinarily long and flexuous with the Cicadidae, are
inserted on the sides of the deferent canals ; while
with Aphis , which has two, and with Notonecta,
Miris and Capsus, which have four, the glandular
tubes open into the Ductus ejaculatorius , con-
jointly with the deferent canals.

8 Psylla, Pyrrhocoris, Velia and Gerris. L.
Dufour (Recherch. &c.) unhesitatingly calls these
dilatations of the deferent canals Vesiculae sem-
inales.

9 L. Dufour (Recherch. kc. PI. X.) also regards
this reservoir as a Vesicula seminalis.

10 The male organs of the Diptera have been de-
scribed by L. Dufour (Ann. d. Sc. Nat. I. 1844,
p. 250), and by Loew (Horae Anat^. p. 9, Tab.
I.-III.), whose account is very detailed and exact.

11 The testicles are long and regularly flexuous
with Myopa, spiral-form with Asilus and Dasy-
pogon, while those of the Hippoboscidae are ex-
tremely long and very torose j see L. Dufour,
Ann. d. Sc. Nat. loc. cit.

1- Stratiomys , alone, has very long and torose
deferent canals.

13 These two glands are very long with Hippo-
hosca, Dolichopus, Asilus, and Stratiomys ; ra-
mose with Trypeta and Psila ; with Leptis , they
are wanting, being replaced, probably, by two swell-
ings situated at the lower extremity of the two def-
erent canals. Empis and Scatopse have two pairs
of glands, one above, the other below.

14 The testicles are carmen-red with Arsrynnis ,
Hippar cilia, Pontia and Liparis ; green with
Lycaena and Sphinx.

15 Suckow ( Heusinger's Zeitsch. II. Taf. X. fig.
10) has found two separated testicles with Ypono-
meuta. The fusion of these organs is complete
with the Papilionidae, Sphingidae,JBombycidae, kc.

16 See Her old, Entwickelungsgesch. d. Schmet-
terl. Taf. IV. XXXII. ( Pontia brassicae ), and

460

THE INSECTA.

§ 353.

With the ITymenoptera,a7) the testicles present many different forms.
Beside two simple ovoid testicular follicles, (18) there are, not unfre-
(juently, also two testicles composed of several long follicles, fasciculate,
and surrounded, together with a portion of the torose deferent canal, by a
common envelope ; but, more commonly, these two testicles are contained in
a capsule situated on the median Line of the body.<l9)

With the Tenthredinidae and the Siricidae, the testicles are separate and
distinct, without capsules, and composed of round follicles disposed botry-
oidally. <2I>) The two deferent canals are usually pretty long, and have,
sometimes, at their lower extremity, two vesicular dilatations which, con-
taining sperm, may be regarded as seminal vesicles. <21) The deferent
canals with the Hymenoptera have, usually, two pyriform accessory glands,
whose excretory ducts unite into a short Ductus ejaculatorius ,(22)

With the winged Strepsiptera, there are two pyriform testicles provided
with very short deferent canals, which dilate above the Ductus ejaculato-
rius into two seminal vesicles ; but nowhere has an accessory gland been
observed.

With the Orthoptera, the two testicles are nearly always composed of a
greater or less number of follicles. With the Acrididae, Locustidae, Ache-
tidae, Blattidae and Mantidae, they are composed of long fasciculated or
imbricated caeca, which, as with the Hymenoptera, are very often sur-
rounded by a common envelope. In some species the two groups of testic-
ular follicles are united into a common mass on the median line of the
abdomen, by this Tunica vaginalis .<28) On the other hand, the Phasmidae,
Libellulidae, Perlidae and Ephemeridae, have a multitude of round folli-
cles, disposed botryoidally around a long dilated portion of each of the
deferent canals. <24) These last are usually very short, and with the Ache-
tidae and Locustidae, only, they are quite long, and spiral from beginning
to end.(-5) Many Orthoptera have highly-developed accessory glands sur-
rounding a short Ductus ejaculatorius , on which they are sometimes dis-
posed in successive groups. A part of this apparatus, in which are

Suckow , Anat. u. physiol. Untersuch. Taf. IV.
( Gastropacha pint).*

If L. D 1/ four (Recherch. sur les Orthopt. p.
399, PI. Y.-X.) lias furnished observations accom-
panied with very many figures ou the male organs
of the Hymenoptera.

IS The testicles are simple with Parnopes , Cy-
nips, Diplolepis and Chelonus.

l‘J There are two unicapsular testicular bundles
with Apis, Xylocopa and Bombus ; see L. Du-
J'our, loc. cit. fig. 53-62. The two testicular fasci-
culi are enclosed in a common capsule with An-
thophora , An thidium, Odynerus, Tiphia , ScoLia ,
Pompilus and Crabro : see L. Du jour, loc. cit.
PI. VI.-IX.

20 L. Dufour, loc. cit. fig. 150-154 ( Tenthredo ,
IJyloloma and Cephus ).

'A The deferent canals terminate each with a
seminal vesicle with Cynips, Chelonus, Apis and
Xylocopa.

22 See Brandt and Ratzeburg , Mediz. Zool. Taf.
XXV. fig. 35 (Apis), and L. Dufour, loc. cit.

+ [ § 353, note 16.] See, also, for histological de-
tails on the internal male organs and their develop-
ment, of the Lepidoptera, Meyer, loc. cit. Siebold
and Kolliker's £eitsch. I. 1849, p. 182. The for-
mula of the development of the testicles is, of
course, the same as that of the development of the

23 See L. Du four, Recherch. sur les Orthopt. PI.
I.-V. There are two distinct fasciculate testicles
with Gryljotalpa , Oecanthus, Ephippigera, and
two groups of long, imbricated follicles with Tetrix.
Locusta and Declicus. The testicles are fused
into one body with Oedipoda and BlattaA

24 See Suckow, in Heusinger's Zeitsch. II.
Taf. XII. fig. 25, Taf. X. fig. 8 ; Rathkt, De Li-
bellur. partibus genital. Tab. I. fig. 3, and L. Du-
four, loc. cit. PI. II. fig. 164, and PI. XII. fig. 204
(Perla and Libellula).

25 See L. Dufour, loc. cit. fig. 25, 36 ( Gryllo -
talpa and Ephippigera).

26 The Perlidae have only two testicular follicles
inserted on the deferent canals. Tetrix, the
Acrididae, Achetidae and Blattidae, have two long
and large fasciculi ; finally, with the Mantidae and
Locustidae, there are, besides these fasciculi, one or
two pairs of shorter bundles ; see L. Dufour, loc.
cit. PI. III.-V.

ovaries 5 but this observer shows that the spermatic
particles are formed, like the ova, while the insect
is in the pupa-state. — Ed.

t [ § 353, note 23.] See also Leidy, Proceed.
Acad. Sc. Philad. 1846, III. p. 80 (Spectrum
femoratum). — Ed.

§ 353.

THE INSECTA.

461

situated here and there vesicular reservoirs, secretes, undoubtedly, with the
Locustidae, a substance used in the formation of the spermatophores. But
with the Phasmidae, Libellulidae and Ephemeridae, the Ductus ejaculato-
rius is wholly deficient in all kinds of glandular appendages.

With the Neuroptera, the various genera present only few modifications in
their male genital organs. With Panorpa, the two testicles are very simple
and ovoid ;(-r) but with the other species they consist of two tufts of long or
round follicles. (2S) With Myrmeleon, and Hemerobius, they are oval and
surrounded by a distinct envelope. The two deferent canals are short,
and always have on their lower extremity two long or ovoid accessory
follicles. <a’>

With the Coleoptera, the male organs vary very much.<30> With the
Carabidae, Hydrocanthari, and Lucanidae, the testicles consist of two
extremely long,torose caeca, (81) of which each is sometimes enclosed in two
special envelopes. (32) The Elateridae, Tillidae, Gantharidae, very many
Heteromera and Coccinellidae, have, on the other hand, a multitude
of round or oblong, short follicles, fasciculate, composing the two testi-
cles, which, (33) in some genera, are here also invested by a capsule. (34)
With the Hydrophilidae, and Pyrochroidae, these organs are composed of
numerous short, aggregated follicles, situated laterally over a wide extent
of the posterior extremity of the deferent canals. (33) With the Staphy-
linidae, and Silphidae, the testicular follicles are pyriform and inserted
botryoidally on the posterior extremity of the simple or multiramose Vasa
deferential AVith the Lamellicornes, Cerambycidae, Curculionidae, and
Crioceridae, these organs are formed after a wholly different type, their
number being two, six, or even twelve on each side. They are usually
round follicles, flattened disc-like, and from which pass off pretty short
excretory ducts to the extremity of the two common deferent canals. (37)

The Vasa defer entia , with the Coleoptera, are usually pretty long ; but
with the Carabidae, Hydrocanthari and Cerambycidae they are very long,
spiral or torose.(38) AVith a few species, only, is each of them dilated in its
course into a Vesicula seminalis. <so> The accessory glands are never want-
ing in this order, and they either open, together with the deferent canals,
into the upper extremity of the Ductus ejaculatorius, or they pass into
these canals before they reach this duct. In very many species this glaud-

27 L. Dufour , loc. cit. fig. 172.

28 Sialis and Phryganea.

20 See L. Dufour , loc. cit. PI. XII. fig. 172-210
( Panorpa , Myrmeleon , Sialis , Phryganea ), and
Suclcow , in Heusinger's Zeitsch. II. Taf. XYI.
Jig. 15 (Sialis).

30 For the male organs of the Coleoptera in gen-
eral, see especially L. Dufour , Ann. d. Sc. Nat.
VI. 1825, p. 152, PI. IV.-IX. and I. 1834, p. 76,
PI. III. IV.

31 With Harpalus , the two caeca are united into
a single clew.

32 Cybister , Scarites, and Clivina , have two
testicles invested by a capsule.

33 Each testicular fasciculus is composed of from
three to seven follicles with Dermestes , Heteroce-
rus, Anthrenus , Oedemera , Helops , Diaperis ,
Tenebrio ; while with Blaps , Pimelia , Mylabris ,
Telcphorus , Bostrichus , the Elateridae and Coc-
cinellidae, their number is much larger.

34 There is a Tunica vaginalis with Clerus,Tri-
c bodes, Mylabris, and which, with Galeruca , is
even common to both testicles.

89*

35 See Swammerdamm , Bib. der Nat. Taf.
XXII. fig. 5 ; Suclcow, in Heusinger's Zeitsch.
II. Taf. X. fig. 1, 2 (Hydrophilus) L. Dufour ,
Ann. d. Sc. Nat. XIII. 1840, PI. VI. A. fig. 18
( Pyrochroa ).

36 The two testicles are multiramose with Silpha ;
see L. Dufour, Ann. d. Sc. Nat. VI. 1825, PI. VI.
fig. 6.

37 Hammaticherus , Anthribus , Lixus and Do-
nacia have two pairs of testicles ; Melolontha and
Prionus six, Trichius nine, and Cetonia twelve.
Beside L. Dufour (loc. cit.), see Suckow, in Heu-
singer's Zeitsch. II. Taf. XI. and Straus , Consid-
£rat. &c. PI. VI.

38 These torosities are even surrounded with a
capsule with Cybister ; see L. Dufour , Ann. d.
Sc. Nat. VI. 1825, PI. V. fig. 1.

39 With the Hydrophilidae, there is a vesicular
dilatation at the lower extremity of the deferent
canals •, but with Anthribus , and Lixus , it is situ-
ated at the opposite extremity.

462

THE INSECTA.

§ 354.

ular apparatus consists of only two simple, longer or shorter caeca, (40)
which are sometimes quite long and torose.(41> Another series of Coleop-
tera have four to eight caecal appendages, disposed in pairs, and variable
as to length and volume. One of these pairs is probably only a reservoir
for the secreted product of the others/421 The Ductus ejaculatorius is
always very muscular, and with very many species, quite long and flexu-
ous, and the penis therefore can be widely protruded during copulation,

§ 354.

The Copulatory organs of the male Insecta are valve-like or forficulate,
horny appendages, (1) which are so variable in their form that the most
allied species differ, in this respect, widely and constantly.®

Beside these proper copulatory organs, situated at the posterior extremity
of the abdomen, there are often on the antennae, the parts of the mouth,
the legs and other regions of the body, auxiliary organs used for seizing
and retaining the female, and which have long been objects of careful
description in zoology.

With most Hemiptera, the posterior extremity of the abdomen conceals
a horny capsule which contains a protractile, tubular penis. With very
many Diptera, the copulatory organs project prominently in the same
region of the body, and consist often of two horny valves of different forms
which envelop a rather long penis.® The Lepidoptera, Hymenoptera,
Orthoptera, and Neuroptera, have two pairs of valves, one internal, the
other external, which enclose a tubular or groove-like penis.®

The Ephemeridae and the Strepsiptera, only, are distinguished by their
very simple copulatory organs; for with the first there is only a simple
penis without a valvular apparatus. This last is replaced by two long,
small, triarticulated stylets, situated on the penultimate abdominal seg-
ment and curved inwardly ; while with the Strepsiptera, the penis, also
naked and horny, is so articulated that it can be applied laterally against
the abdomen, like the blade of a knife in its handle.

With the Libellulidae, however, the orifice of the Ductus ejaculatorius is
most simple, being covered only by two very small oval valves. But the
penis is not wanting with these Insecta ; it is singularly concealed, together
with a horny-walled seminal vesicle, in a fossa situated at the base of the

40 With the Carabidae, Ilydrocanthari, and with
Mordclla, Anthribus , Galeruca and Coccinella.

41 Melolontha , Cetonia and Lucanus ; see L.
Du four , Straus , and Suckow , loc. cit,

42 With the St<> phylinidae, Cantharidae, Byrrhi-
dae, Elateridae, Tillidae, Melo'idae, Tenebrionidae,
Pyrochroklae, Dermestidae, Cerambycidae, with
Donacia , Heterocerus , &c. ; see L. Dufour ,
Suckow , loc. cit. and Brandt , Mediz. Zool. II.
Tat XVII. XIX. This glandular apparatus is
specially developed with HydrophiLus piceus ,
where, of the four pairs, one is distinguished for its
length and thickness, and is composed at its extrem-
ity of numerous small follicles *, see Swammer-
damm, Bib. der Nat. Taf. XXII. fig. 4 *, L. Du-
four, loc. cit. VI. PI. VI. fig. 7, and Suckow , loc.
cit. Taf. X. fig. 1, 3.

1 See Burmeister , Handb. &c. I. p. 227, Taf.
XIII.

2 As yet, these differences in form of the external
male organs have been of little service to entomolo-
gists in the distinction of species, although, had

they been well understood, the formation of many
bad species might have been prevented. They
prevent allied species from producing bastards by
adulterous connections, for the hard parts of the
male correspond so exactly with those of the female,
that the organs of one species cannot fit those of
another. L. Dufour has, therefore, properly
termed these copulatory organs as u la marantic
de la conservation des types , et la sauvegarde
de la legitemite de Vespicc .”

3 This horny apparatus, from its large and often
tumid lateral valves is quite prominent with the
Dolichopidae, Empidae, with Asi/us , Laphria ,
Ctenophora , Nematocera , and other Tipulidae.
See Schummel , Beitr. zur Entomol. Taf. I.-III.
( Tipula ).

4 With the Panorpidae, these copulatory organs
are changed into very large pincers ; while with
Psyche , the very long penis is protractile like the
tubes of a telescope, thus enabling these butterflies
to copulate with their females which remain con-
cealed in sacks.

§ 355.

THE INSECTA.

463

abdomen.® This penis is composed of three articles with Aeschma , Libel-
lula , and Gomphus ; but of one only with Calopteryx, and Agrion, with
which it is not directly adherent to the seminal vesicle. The male Libel-
lulidae are obliged, before copulation, to fill their vesicula seminalis, which
is situated at the base of the abdomen. This they accomplish by bending
the posterior extremity of the abdomen, so as to meet and empty the semen
into this vesicle. They then seize the female by the neck, by means of their
anal pincers, and she places her genital orifice in contact with the copula-
tory apparatus of the male.® These anal pincers of the males have very
distinct specific characteristics, while the females, on their part, have, in
the separate species, equally specific sculptured markings on the protho-
rax.®

With the Coleoptera, the copulatory organs consist of a more or less
horny sheath enveloped by a membranous prepuce, and containing a
broadly-flattened penis which consists of a canal supported by two lateral
horny ridges. At rest, these organs are entirely withdrawn into the abdom-
inal cavity, but can be widely protruded out of it by means of a very remark-
able muscular apparatus.® With the male individuals of Dennestes, there
is a median orifice on the third and fourth abdominal segments, from which
projects a brush of stiff bristles connected with a round muscular body situ-
ated on the internal surface of each of these segments. This brush is un-
doubtedly some way connected with the act of copulation.®

§ 355.

The development of the larvae of Insecta in the egg, occurs in the same
manner as with most of the other Arthropoda. After the unusually early dis-
appearance of the genninative vesicle/11 there is formed, from a superficial
and partial segmentation, a round or oblong-oval blastoderma, whose
hyaline aspect contrasts with that of the rest of the vitellus.® This bias-

<5 For the copulatory organs of the Libellulidae,
see Rnthki , De Libellar. partibns genital., and my
researches in Germans Zeitsch. II. p. 421.

6 The act of copulation of the Libellulidae has
been represented by S luammerdarnm , Bib. der
Nat. Taf. XII. fig. 3 5 Reaumur , Mem. &c. VI.
PI. XL. XLI. ; and Roesel, Insectenbelust. Tli.
IT. Insect, aquat. Class. II. Tab. X.

7 The different forms of these pincers have been
figured in Charpentier, Horae Entomol. Tab. I.,
and Selys Longchamps , Monogr. des Libellul.
d’Europe, PI. I.-IV.

8 See Straus , Consider. &c. PI. III. Y.

'J See my observations in the Entomol. Zeitung.
1840, p. 137, and BrulU , Ann. d. 1. Soc. Entom.
VII. 1838, p. LIII. The golden-colored tuft
of hairs situated at the base of the abdomen
with the males of Blaps , does not correspond to
that of Dermestes , because it is only external and
does not project into the interior of the body.

* [ § 355, note 2.] I am not aware that the
numerous researches upon the embryology of the
Insecta made within a few years, have added any
new phases to the general type of development of
these animals as brought out by the earlier inves-
tigators. The type of development with the Arth-
ropoda is essentially the same in all of the classes
of this section. What late observers have done,
therefore, is the tracing of some of the secondary

1 The germinative vesicle is never observed in
eggs that have been layed ; it has disappeared
even in those still in the oviduct ; this disappear-
ance would not appear, therefore, to depend upon
the act of fecundation.

if The first phases of the development of Insecta
have been studied by Harold (Disquisit. de Anim.
vertebr. carent. in ovo format. 1835-38) with
Spinx ligustri and Musca vomitoria ; and by
Kolliker (Observ. de prima Insect. genesi,1842, or
Ann. d. Sc. Nat. XX. 1843, PI. X.-XI1.) with
Chironomus , Simulia , and Donacia.

The ulterior phases have been traced by Rathke
(. Meekers Arch. 1832, p. 371, Taf. IV. and Mul-
ler's Arch. 1844, p. 27, Taf. II.) with Blatta
orienta/is and Gryllotalpa vulgaris ; and by
Nicolet (Recherch. &c. p. 18, PI. I.) with the
Poduridae.*

conditions of formation belonging to the different
groups, and the observation of the details of de-
velopment of different internal and external organs.
Those anomalies of development and reproduction,
which continued research shows to be far from un-
common with the Insecta, will ultimately be found,
probably, referable all to the phenomena, we have
discussed below, of the Apliididae. — Ed.

464

THE INSECTA.

§ 355.

toderma, which corresponds to the ventral side of the future embryo, extends
gradually in all directions and at last encompasses the whole vitellus, — its
borders meeting on the dorsal surface. It may be divided into an exter-
nal or serous, and an internal or mucous layer. In the first of these is de-
veloped, on the median abdominal line, the ventral cord ; while the second
forms a semi-canal which gradually surrounds the vitellus and at last com*
pletely enveloping it, is changed into the digestive canal. The various ap-
pendages of this canal are subsequently formed by simple constrictions or
deverticula from its cavity ; while the other abdominal viscera are directly
developed from a special blastoderma.

Upon the external surface of the serous layer are formed the parts of the
mouth, the tactile organs, the legs, and the other appendages of the body,
whose articulations, like those of the body itself, are produced by constric-
tions.

The dorsal vessel is formed between the two blastodermic layers on the
side opposite that of the ventral cord. This development of the embryo
takes place at the expense of the vitellus, which, enclosed in the digestive
canal, is gradually consumed.*

* [ End of § 355.] The subject, which has been
frequently alluded to in this book, — the singular
mode of reproduction of the viviparous Aphldidae,
is one of so much interest and importance in physi-
ology, that I propose to give it something more
than a brief mention. Moreover, I have enjoyed
excellent opportunities for the study of these phe-
nomena in question, and have advanced an inter-
pretation of them, and their like elsewhere, quite
different from that usually received.

My observations were made upon Aphis caryae
(probably Lachnus of Illiger, or Cinara of Cur-
tis), one of the largest and most favorable species
for these investigations. This was in the spring of
1853. The first colony, on their appearance from
their winter quarters were of mature size, and con-
tained, in their interior, the developing forms of the
second colony quite far advanced in formation. On
this account it was the embryology of the third
series or colony, that I was able to first trace. A
few days after the appearance of the first colony
(A), the second colony (B), still within the former,
had reached two-thirds of them full embryonic size }
the arches of the segments had begun to close on the
dorsal surface, and the various appendages of the
embryo were becoming promiuent $ the alimentary
canal was more or less completely formed, although
distinct abdominal organs of any kind belonging to
the digestive system were not apparent.

At this time, and while the individuals B. were
not only in the abdomen of their parents A., but
were also enclosed each in its primitive egg-like
capsule j at . this time, I repeat, appear the first
traces of the germs of the third colony, C. Their
first traces consisted of small egg-like bodies, ar-
ranged two, three, or four in a row, and attached
at the locality where are situated the ovaries in the
oviparous forms of the Apliididae. These egg-like
bodies were either single nucleated cells of one
three-thousandth of an inch in diameter, or a small

number of such cells enclosed in a simple sac.
These are the germs of the third generation or
colony, and they increase pari passu with the de-
velopment of the embryo in which they are formed,
and this increase of size takes place not by the
segmentation of the primitive cells, but by the en-
dogenous formation of new cells within the sac.
After this increase has continued for a certain time,
these bodies appear like little oval bags of cells, —
all the component cells being of the same size and
shape, — there being no one particular cell which
is larger and more prominent than the others, and
which could be comparable to a germinative vesi-
cle. While these germs are thus constituted the
formation of new ones is continually taking place.
This occurs by a kind of constriction-process of
the first germs *, one of the ends of these last being
pinched off, as it were, and so, what was before a
single body or sac, becomes two which are attached
in a moniliform manner. The new germs thus
formed may consist each of a single cell only, as I
have often seen *, but they soon attain a more uni-
form size by the endogenous formation of new cells
within the sac in which it is enclosed. In this way
the germs are multiplied to a considerable number,
the nutritive material for their growth being, ap-
parently, a fatty liquid in which they are bathed,
contained in the abdomen, and which is thence de-
rived from the abdomen of the first parent. When
these germs have reached the size of about one
three-hundredth of an inch in diameter, there ap-
pears on each, near the inner pole, a yellowish,
vitellus-looking mass or spot, composed of yellow-
ish cells, which, in size and general aspect, are dif-
ferent from those constituting the germ proper.
This yellow mass increases after this period, pari
passu with the germ, and at last lies like a cloud
over and partially concealing one of its poles. I
would, moreover, insist upon the point that it does
not gradually extend itself over the whole germ-

§ 355,

THE INSECTA.

465

mass, and is, therefore, quite unlike a proligerous
disc.

When these egg-like germs have attained the size
of one one-hundred-and-fiftieth of an inch in di-
ameter, there begins to appear distinctly the sketch-
ing or marking out of the future embryo. This
sketching consists at first of delicately-marked re-
treatings of the cells here and there 5 but these last
soon become more prominent from sulcations, and,
at last, the form of an articulated embryo is quite
prominent.

During this time, the yellowish, vitellus-looking
mass has not changed its place, and although it is
somewhat increased in size, yet it appears other-
wise the same. When the development has pro-
ceeded a little further, and the embryo has as-
sumed a pretty definite form, the arches of the
segments, which have hitherto remained gapingly
open, appear to close together on the dorsal sur-
face, thereby enclosing the vitellus-looking mass
within the abdominal cavity. It is this same vitel-
loid mass thus enclosed, which furnishes the de-
velopment of the new germs (which in this case
would be those of the fourth colony, or D), and this
germ development here commences with the clos-
ing up of the abdominal cavity, and then the same
processes we have just described are repeated.

The details of the development subsequent to
this time, — the formation of the different systems
of organs, &c., are precisely like those of the de-
velopment of true oviparous Arthropoda in gene-
ral } and although the ovoid germ has, at no time,
the structural peculiarities of a true ovum, — such
as a real vitellus, germinative vesicle and dot, yet
if we allow a little latitude in our comparison and
regard the vitellus-looking mass as the mucous ,
and the germ-mass proper as the serous fold of
the germinating tissue, as in true ova ; if this com-
parison of parts can be admitted, then the analogy
of the secondary phases of development between
these forms, and true ova of the Arthropoda, can
be traced to a considerable extent.

These secondary phases of development need not
here be detailed, for they correspond to those de-
scribed by Herold , Kblliker , of the true ovum*in
other Insecta, and which, too, I have often traced in
various species of the Arthropoda in general.

When the embryo is fully formed and ready to
burst from its capsule in which it has been de-
veloped, it is about one-sixteenth of an inch in
length, or more than eight times the size of the
germ, when the first traces of development in it
were_seen. From this last-mentioned fact, it is
evident that, even admitting that these germ-masses
are true eggs, the conditions of development are
quite different from those of the eggs of the truly vivi-
parous animals, for, in these last, the egg is merely
hatched in the body instead of out of it, and, more-
over, it is formed exactly as though it was to be
deposited, and its vitellus contains all the nutritive
material required for the development of the em-
bryo until hatched. With the Aphididae, on the
other hand, the developing germ derives its nutri-
tive material from the fatty liquid in which it is

bathed, and which fills the abdomen of the parent.
The conditions of development in this respect, are
here, therefore, more like those of the Mammalia and
the whole parent animal may be regarded in one
sense as an individualized uterus filled with germs,
— for the digestive canal with its appendages
seems to serve only as a kind of laboratory for the
conversion of the succulent liquids this animal ex-
tracts from the tree on which it lives, into this fatty
liquid which is the nutritive material of the germs.

Omitting the curious and interesting details of
the further history of the economy of these Insecta,
as irrelevant to the point in discussion, we will now
turn to see what view we should take of these pro-
cesses, and what is their physiological interpreta-
tion. In the first place it is evident that the germs
which develop these viviparous Aphides are not
true eggs *, they have none of the structural char-
acteristics of these last, — such as a vitellus, a
germinative vesicle and dot 5 on the other hand
they are at first simple collections, in oval masses,
of nucleated cells. Then again, they receive no
special fecundating power from the male, which is
the necessary preliminary condition of all true
eggs } and furthermore the appearance of the new
individual is not preceded by the phenomena of
segmentation, as is also the case with all true eggs.
Therefore, their primitive formation, their develop-
ment and the preparatory changes they undergo
for the evolution of the new individual, are all dif-
ferent from those of real ova.

Another point of equal importance is these vivi-
parous individuals of the Aphides have no proper
ovaries and oviducts. Distinct organs of this kind
I have never been able to make out. The germs,
as we have before seen, are situated in moniliform
rows, like the successive joints of confervoid plants,
and are not enclosed in a specirl tube. These rows
of germs commence, each, from a single germ-mass
which sprouts from the inner surface of the animal,
and increases in length and the number of its com-
ponent parts by the successive formation of new
germs by the constriction process as already de-
scribed. Moreover, these rows of germs which, at
one period, closely resemble in general form, the
ovaries of some true Insecta, are not continuous
with any uterine or other female organ, and there-
fore do not at all communicate with the external
world, on the other hand, they are simply attached
to the inner surface of the animal, and their com-
ponent germs are detached into the abdominal
cavity as fast as they are developed, and thence
escape outwards through a Porus genitalis.

With these data, the question arises, what is the
proper interpretation to be put upon these repro-
ductive phenomena we have just described ? My
answer would be that the whole constitutes only a
rather anomalous form of gemmiparity 5 as already
shown, the viviparous Aphididae are sexless ; they
are not females, for they have no female organs,
they are simply gemmiparous , and the budding is
internal, instead of external as with the Polypi and
Acalephae ; moreover this budding takes on some of
the morphological peculiarities of oviparity but these

466

THE INSECTA.

<§>355.

peculiarities are economical and extrinsic, and do
not touch the intrinsic nature of the processes there-
in concerned. Viewed in this way, the different
broods or colonies of Aphididae cannot be said to
constitute as many true generations, any more than
the different branches of a tree can be said to con-
stitute as many trees ; on the other hand the whole
suite, from the first to the last, constitute but a
single true generation. I would insist upon this
point as illustrative of the distinction to be drawn
between sexual and gemmiparous reproduction.
Morphologically, these two forms of reproduction,
have, it is true, many points of close resemblance,
but there is a grand physiological difference, the
perception of which is deeply connected with our
highest appreciation of individual animal life.

A true generation must be regarded as resulting
only from the conjugation of two opposite sexes, —
from a sexual process in which the potential repre-
sentatives (sperjnatic particle and ovum) of two op-
posite sexes are united for the elimination of one*
germ. The germ power thus formed may be ex-
tended by gemmation or fission, but it can be
formed only by the act of generation, and its play
of extension by budding or by division must always
be within a certain cycle, which cycle is recom-
menced by the new act of the conjugation again of
the two sexes. In this way the dignity of the
ovum as the primordium of all true individuality,
is maintained.

I have thus treated this subject in some detail,
not only from its wide bearing in the physiology of
reproduction, but also from its direct relation to
many phenomena alluded to in the preceding
pages. In the memoir from which I have made
this extract (read before the Amer. Acad. Arts
and Sc., Oct. 11, 1853) I have entered into a full

discussion of those many points suggested by these
studies. One of these, is, the relation of this subject
to some of the various doctrines of development,
which have been advanced in late years, such as
that of Alternation of Generation , by Steen-
strup , and that of Parthenogenesis by Owen. I
have there attempted to show that the phenomena
of these doctrines, as advanced by their respective
advocates, all belong to those of gemmiparity, and
that therefore Alternation of Generation and Par-
thenogenesis in their implied sense, are misno-
mers in physiology. Another point there treated
in extenso, is the identity of this mode of repro-
duction we have just described in the Aphididae,
with that observed in the so-called hibernating eggs
of the Entomostraca (see above, §> 290) and the like
phenomena observed in nearly every class of the
Invertebrata. They are all referable, in my opinion,
to the conditions of gemmation, modified in each
particular case, perhaps, by the economical rela-
tions of the animal.

See for some recent writings on this peculiar
form of reproduction with the Insecta, and which
contain many interesting physiological remarks,
Leydig , Die Dotterfurchung nach ilirem Vor-
koqunen in der Thierwelt und nach ihrer Bedeu-
tung, in the Isis, 1848, lift. 3 5 also, Einige Bemer-
kungen fiber die Entwickelung der Blattl&use, in
Siebold and Kiilliker's Zeitsch. II. 1850, p. 62 $
also Zur Anatomie von Coccus hesperidum, in Ibid.
1853, V. p. 1 5 Victor Carus , Zur naheren Kennt-
niss des Generationswechsels, Leipsig, 1849 5 and
Siebold , as referred to in my note under § 348 note
4. I cannot here discuss the often similar and
dissimilar views to those of my own above detailed,
expressed by these different investigators. — Ed.

INDEX

ABBREVIATIONS.

Acal ., Acalephae.
Aceph ., Acephala.
Ann., Annelides.
Arach ., Arachnoidae.

Ceph'd Cephalopoda.
Ceph'r., Cephalophora.
Crus., Crustacea.
£cA., Echinodermata.

He/., Helminthes.
/n/., Infusoria,
/ns., Insecta.
Po/., Polypi.

Rhiz b, Rhizopoda.
PoZ., Rotatoria.
Turb., Turbellaria.

IV. B. T/ie Numbers refer to the Paragraphs .

A®

Acalephae, 53.

Acephala, 170.

Aciculi, Ann. 145.

Air cavity or reservoir, Acal. 65.

Ambulacra, Ech. 77, 91.

Ampulla, of Poli, Ech. 92.

Annelides, 142.

Antennae, Ann. 149, 152. Arach. 306. Ins. 332.
Anus, Inf. 15. Ech. 82. Hel. 107. Rot. 136.
Aceph. 188, 189. Ceph’r. 214. Ceph’d. 249.
Crus. 279. Arach. 307. Ins. 338.

Apparatus, ceraceous, Ins. 347.

digestive. Inf. and Rhiz. 11. Pol. 35.

Acal. 61. Ech. 82. Hel. 106. Turb. 125.
Rot. 136. Ann. 152. Aceph. 188. Ceph’r.
213. Ceph’d. 248. Crus. 278. Arach. 306.
Ins. 337.

ejaculatory, of sperm. Ceph’d. 259.

masticatory. Ech. 84. Hel. 108. Rot.

136. Ann. 154. Ceph’r. 213. Ceph’d. 248.
Crus. 279. Arach. 306. Ins. 337.

mucous. Ins. 349.

respiratory. Inf. and Rhiz. 18. Pol. 41.

Acal. 63. Ech. 89. Hel. 112. Turb. 126.
Rot. 138. Ann. 158. Aceph. 193. Ceph’r.
219. Ceph’d. 253. Crus. 285. Arach. 311.
Ins. 341.

rotatory. Rot. 133.

sebaceous. Ins. 349.

sericeous. Arach. 315. Ins. 347.

suctorial. Hel. 103. Arach. 306. Ins.

337, 338.

tentacular. Ech. 83.

venomous. Arach. 315. Ins. 347, 349.

Appendices, caecal. See Caecum.

cutaneous. Ann. 143.

Arachnoidae, 295.

Arms. Aceph. 185. Ceph’d. 237.

Arolium. Arach. 299. Ins. 326.

Arteries. See Circulatory System.

Audition. See Auditive Organs.

B.

Balancers. Ins. 326.

Bladders, natatory. Acal. 58. Ceph’d. 256.
Blood. Pol. 39, 41. Hel. 110. Ann. 156. Aceph.
191. Ceph’r. 216. Ceph’d. 251. Crus. 282.
Arach. 309. Ins. 340.

Brain. Ann. 146, 147. Ceph’r. 206. Ceph’d. 240,
Crus. 270. Arach. 300. Ins. 328.

Branchiae. Ech. 89. Ann. 159, 160. Aceph.
193. Ceph’r. 220. Ceph’d. 253. Crus. 285.
Arach. 312. Ins. 342.

Bristles. Ann. 145. Aceph. 185.

Bursa Needhami. Ceph’d. 259.

Byssus. Aceph. 179.

C.

Caecum. Ech. 85, 86. Hel. 108. Ann. 154. Aceph.
189. Ceph’d. 249. Crus. 279. Arach. 307.
Ins. 338.

Caeca, hepatic. See Liver.

Calamistrum. Arach. 315.

Canal, intestinal. Ann. 154. Aceph. 189. Ce-
ph’r. 214. Ceph’d. 249. Crus. 279. Arach.
307. Ins. 338.

stony. Ech. 75.

Canals, aquiferous. See Aquiferous System.

lateral. Hel. 110.

longitudinal. Hel. 111.

Capsule, genital. Ceph’d. 260.

egg. Ceph’d. 258.

ovarian. Ceph’d. 258.

Cardo. See Hinge.

Cavity, branchial. Ceph’r. 220.

incubatory. Crus. 292.

pulsatile. Inf. 16.

respiratory. Aceph. 194. Crus. 285.

Cell, lateral. Ceph’d. 254.

Cells, chromatophoric. Ceph’d. 233.

hepatic. See Liver.

vitelline. Hel. 115. Turb. 129.

468

INDEX

Cephalophora, 201.

Cephalopoda, 230.

Cheliceres. Arach. 306.

Circles, of hooks. Hel. 103.

osseous. Ech. 73.

Cirri. Ann. 119, 152.

Cloaca. Arach. 307.

genital. Ceph’r. 227.

Cocoon. Ann. 166.

Collar. Ann. 167.

Corallum. Pol. 25.

Cord, calcareous. Ech. 75.

ventral. Ech. 80. Hel. 104. Ann. 146.

Ceph’r. 206. Crus. 270. Arach. 300. Ins.
328.

Corpus adiposum. Crus. 281. Ins. 339.

spongiosum. Ceph’d. 255.

Corpuscles, germinative. Hel. 118.

Crop. Ceph’d. 249. Ins. 338.

Crustacea, 262.

Cups, sucking. Hel. 103.

D.

Dart. Ceph’r. 227.

Dart-sac. Ceph’r. 227.

Development. Pol. 51. Ech. 98. Hel. 118.
Turb. 129. Rot. 141. Ann. 169. Aceph.
200. Ceph’r. 229. Ceph’d. 261. Crus. 294. *
Arach. 320. Ins. 355.

of Mollusca in Holothurio'idea, 229.

Disc, vibratile. Rot. 133.

Drums. Ins. 327.

E.

Echinodermata, 71.

Eggs. Pol. 44, 45. Acal. 67. Ech. 95. Hel.
115, 116. Turb. 128. Rot. 140. Ann. 163.
Aceph. 198. Ceph’r. 225. Ceph’d. 257, 258.
Crus. 290. Arach. 316. Ins. 348.

hibernating. Cr. 292.

Elytra. Ins. 326.

Envelope, cutaneous. Inf. and Rhiz. 6. Pol. 25.
Acal. 54. Ech. 72. Hel. 100. Turb. 121.
Rot. 131. Ann. 143. Aceph. 171. Ceph’r.
202. Ceph’d. 233. Crus. 263. Arach. 296.
Ins. 322.

Eyes. See Organs of Vision.

crabs. Crus. 289.

F.

Fins. Ceph’d. 234. Crus. 268.

Foot. Aceph. 178. Ceph’r. 204. Crus. 268.
Foramina, repugnatoria. Crus. 289.

Fossettes, respiratory. Ann. 158.

G.

Ganglia, radiating. Ceph’d. 241.

pedal. Ceph’r. 208.

Generation. See Generative Organs.

alternation of. Pol. 45. Acal. 70. Hel.

118. Ins. 348, 355.

Germs, egg. Hel. 115.

Girdle. Ann. 167.

Gizzard. Ins. 338.

Glands, albumen. Ceph’r. 227.

anal. Ins. 347.

of Bojanus. Aceph. 196.

genital accessory. Hel. 116, 117. Ann.

166. Ceph’r. 227. Ceph’d. 258. Arach. 315.
Ins. 349.

hermaphrodite. Ceph’r. 227.

muciparous. Ins. 352.

nidamental. Ceph’d. 258.

Glands, odoriferous. Ins. 347.

poison. Arach. 315. Ins. 347.

salivary. Ech. 86. Hel. 109. Turb. 126.

Rot. 136. Ann. 155. Aceph. 190. Ceph’r.
215. Ceph’d. 250. Crus. 280. Arach. 308.
Ins. 339.

sebaceous. Ins. 349.

sericeous. Arach. 315. Ins. 347.

H.

Heart. Ech. 88. Ann. 156. Aceph. 191. Ceph’r.
217. Ceph’d. 252, 255. Crus. 283. Arach.
309. Ins. 340.

Helminthes, 99.

Hinge. Aceph. 174.

Hooks. Ech. 75. Hel. 103.

I.

Ink-sac. Ceph’d. 256.

Infusoria, 3.

Insecta, 321.

Intestines. Ann. 154. Aceph. 189. Ceph’r. 214.
Ceph’d. 249. Crus. 279. Ins. 338. See also
Digestive Tube.

J.

Jaws. Rot. 136. Ann. 153. Ceph’r. 213. Ceph’d.
248. Crus. 278. Arach. 306. Ins. 337.

K.

Kidneys. Aceph. 196. Ceph’r. 223. Ceph’d.

255. Ins. 345.

Knobs, fleshy. Ann. 145.

L.

Labium. Ins. 337.

Labrum. Crus. 278. Ins. 337.

Lantern, of Aristotle. Ech. 84.

Larvae, nursing. Hel. 118.

Legs. Crus. 268. Arach. 299. Ins. 326.
Lemnisci. Hel. 110.

Ligament, elastic. Aceph. 174.

Liver. Pol. 37. Acal. 61. Ech. 86. Hel. 109.
Turb. 125. Rot. 136. Ann. 155. Aceph.
190. Ceph’r. 215. Ceph’d. 250. Crus. 280.
Arach. 308. Ins. 339.

Lungs. Ann. 159. Ceph’r. 221. Crus. 287.
Arach. 313.

M.

Mandibulae. Crus. 278. Ins. 337.

Mantle. Aceph. 171. Ceph’r. 202. Ceph’d. 234.
Crus. 265.

Maxillae. Crus. 278. Ins. 337.

Membrane, argenteous. Ceph’d. 247.

natatory. Ceph’d. 234.

Metamorphosis. Pol. 52. Acal. 70. Hel. 118.
Ann. 169. Aceph. 200.

Mouth. Inf. 15. Pol. 36. Acal. 61. Ech. 82,
84. Hel. 107. Turb. 125. Rot. 136. Ann.
153. Aceph. 188, 189. Ceph’r. 213. Ceph’d.
248. Crus. 278. Arach. 306. Ins. 337.
Muscles. See Muscular System.

N.

Nerves, pneumogastric. Ceph’d. 241.
respiratory. Ins. 328.

INDEX.

469

Nerves, splanchnic. Ann. 148. Aceph. 184. Ceph’r.
219. Ceph’d. 242. Crus. 273. Arach. 302.
Ins. 331.

Nucleus, generative. Inf. and Rhiz. 21.

intestinal. Aceph. 189.

Nurses. See Nursing Larvae.

O.

Oars, or oarlike organs. Crus. 268.

(Esophagus. Ann. 154. Aceph. 189. Ceph’r.
214. Ceph’d. 249. Crus. 279. Arach. 306.
Ins. 338.

Olfaction. See Organs of.

Opercula, branchial. Crus. 286.

Operculum. Ceph’r. 203.

caducum. Ceph’r. 203.

Organs, auditive. Pol. 34. Acal. 60. Ann. 151.
Aceph. 186. Ceph’r. 211. Ceph’d. 246.
Crus. 276. Arach. 305. Ins. 335.

bird’s-head-like. Pol. 32.

of the Byssus. Aceph. 179.

copulatory. Ann. 164, 167. Ceph’r. 227.

Ceph’d. 259. Crus. 291, 293. Arach. 319.
Ins. 354.

generative. Inf. and Rhiz. 20. Pol. 43.

Acal. 66. Ech. 95. Hel. 114. Turb. 128.
Rot. 140. Ann. 162. Aceph. 197. Ceph’r.
225. Ceph’d. 257. Crus. 290. Arach. 316.
Ins. 348.

gyratory. Crus. 285.

locomotive. Inf. 7. Rhiz. 8. Pol. 31.

Acal. 57. Ech. 77. Ilel. 103. Turb. 122.
Rot. 133. Ann. 145. Aceph. 177. Ceph’r.
204. Ceph’d. 238. Crus. 268. Arach. 299.
Ins. 326.

muciparous. Ceph’r. 224.

nettling. Pol. 27. Acal. 56. Turb. 121.

Ceph’r. 224.

olfactory. Ceph’d. 245. Crus. 275. Arach.

304. Ins. 334.

phosphorescent. Ins. 347.

prehensile. Pol. 36. Acal. 56. Ech. 78.

Crus. 268.

rotatory. See Rotatory Apparatus.

salivary. See Salivary Glands.

of Secretion. Inf. and Rhiz. 19. Pol. 42.

Acal. 65. Ech. 94. Hel. 113. Turb. 127.
Rot. 139. Ann. 161. Aceph. 196. Ceph’r.
223, 224. Ceph’d. 255, 256. Crus. 288, 289.
Arach. 314, 315. Ins. 345, 356, 347.

of Sense. Inf. and Rhiz. 9, 10. Pol. 34.

Acal. 60. Ech. 81. Hel. 105. Turb. 124.
Rot. 135. Ann. 149, 150, 151. Aceph. 185,
186, 187. Ceph’r. 210, 211, 212. Ceph’d.
243, 244, 245, 246, 247. Crus. 274, 275, 276,
277. Arach. 303, 304, 305. Ins. 332, 333,
334, 335, 336.

vitellus-secreting. Hel. 115. Turb. 128.

sericeous. Ins. 347.

soniferous. Ins. 327.

suctorial. Crus. 278. See also Proboscis.

of Taste. Inf. 10. Ceph’d. 244. Arach.

304. Ins. 333.

of Touch. Inf. 10. Pol. 34. Ech. 81.

Hel. 105. Turb. 124. Rot. 135. Ann. 149.
Aceph. 185. Ceph’r. 210. Ceph’d. 243.
Crus. 274. Arach. 303. Ins. 332.

urinary. Ceph’r. 223. Ceph’d. 255. Crus.

288. Arach. 314. Ins. 345.

venomous. Pol. 28. See Venomous Appa-

vibratile. Inf. 8. Pol. 26. Acal. 58.

of Vision. Inf. 9. Pol. 34. Acal. 60. Ech.

81. Hel. 105. Turb. 124. Rot. 135. Ann.
150. Aceph. 187. Ceph’r. 212. Ceph’d. 247.

Crus. 277. Arach. 305. Ins. 336.

. vortical. Crus. 285.

Orifice, cloacal. Rot. 136.

Orifices, genital. Ech. 97. Hel. 115. Turb. 128.
Ann. 166. Ceph’r. 227. Ceph’d. 258. Crus.
290. Arach. 318. Ins. 351.

40

Orifices, respiratory. Ech. 93.

Os sepiae. Ceph’d. 235.

Ovaries. Pol. 45, 47. Acal. 68. Ech. 97. HeL
115, 116, 117. Turb. 128. Rot. 140. Ann.
166, 168. Aceph. 198. Ceph’r. 228. Ceph’d.
258. Crus. 291. Arach. 316. Ins. 349.
Ovipositor. Arach. 318. Ins. 332, 351.

P.

Palpi. Cr. 278. Arach. 303, 306. Ins. 332, 337.
Pancreas. Rot. 136. Ceph’d. 250. Ins. 339.
Pedicellariae. Ech. 78.

Peduncle. Aceph. 180.

Penis. Hel. 115, 116, 117. Turb. 128. Ann. 166.
Ceph’r. 227, 228. Ceph’d. 259. Crus. 291,
293. Arach. 319. Ins. 354.

Penises, secondary. Crus. 293.

Perisoma. Ech. 72.

Pharynx. Turb. 125. Ann. 153. Ceph’r. 213.

Ceph’d. 248.

Pinnulae. Ech. 72.

Plates, ambulacral. Ech. 72.

cribriform. Ech. 97.

genital. Ech. 97.

madreporic. Ech. 75.

ocellary. Ech. 81.

Plexus, splanchnic. See Splanchnic Nerves.
Pouch, cirrous. Hel. 115.

copulatory. Turb. 128. Ins. 349.

fecundating. Ceph’r. 227.

incubating. Crus. 292.

problematical red. Crus. 286.

Polypi, 24.

Polypary. Pol. 25.

Pores, ambulacral. Ech. 72, 77.

Proboscis. Hel. 103. Ann. 149. Crus. 278.

Arach 306. Ins. 332, 337.

Propagation. See Organs of Generation.

Prostate. Ceph’r. 227.

R.

Rays, branchial. Ann. 152.

Receptaculum seminis. Turb. 128. Ceph’r. 227.

Crus. 292. Arach. 318. Ins. 349.

Rectum. Ech. 85. Rot. 136. Ann. 154. Aceph.
189. Ceph’r. 214. Ceph’d. 249. Arach. 307.
Ins. 338.

Reservoir, egg. Ann. 166. Crus. 290, 292.

sperm. See Receptaculum Seminis.

Rhizopoda, 4.

Ring, aquiferous. Ech. 92.

oesophageal. Ech. 80. Hel. 104.' Ann.

146. Aceph. 183. Ceph’r. 206. Ceph’d. 240.
Crus. 270. Arach. 300. Ins. 328.

osseous. Ech. 73.

Rostellum. Hel. 103.

Rostrum. Ins. 337.

Rotatoria, 130.

S.

Shell. Aceph. 174. Ceph’r. 203. Ceph’d. 235.
Crus. 265.

Siphon. Aceph. 173. Ceph’r. 203, 220. Ceph’d.

235. Ins. 343.

Silk. Arach. 315. Ins. 34^

Skeleton, cutaneous. Pol. 25. Acal. 54. Ech. 72.
Hel. 101. Crus. 263. Arach. 296. Ins. 322.

internal. Ech. 73. Aceph. 175. Ceph’d.

231. Ins. 322.

Skin. See Cutaneous Envelope.

Smell. See Olfactory Organs.

Spermatophores. Ceph’d. 259. Crus. 290.
Spermatic Particles. Pol. 46. Acal. 67. Ech.
95. Hel. 115, 116, 117. Turb. 128. Rot.
140. Ann. 163. Aceph. 198. Ceph’r. 225.
Ceph’d. 257. Crus. 290. Arach. 316. Ins. 348.

470

INDEX

Spinnerets. Arach. 315. Ins. 347.

Stalk, crystalline. Aceph. 189.

Stemmata. See Organs of Vision.

Sting3. Ann. 145. Crus. 264. Ins. 347.

Stomach. Inf. 12. Pol. 37, 38. Acal. 61. Ech.
85. Rot. 136. Ann. 154. Aceph. 189.
Ceph’r. 214. Ceph’d. 249. Crus. 279. Arach.
307. Ins. 338.

Suckers. Ech. 77. Hel. 103.

Sucking Cups. Hel. 103. Ann. 145, 153. Ceph’r.

204. Ceph’d. 238. Arach. 299.

Support, calcareous. See Internal Skeleton.
System, aquiferous. Pol. 41. Acal. 63. Ech. 91.
Hel. 112. Turb. 126. Rot. 138. See also
Aquiferous Vessels.

circulatory. Inf. and Rhiz. 16. Pol. 39.

Acal. 62. Ech. 87. Hel. 110. Turb. 126.
Rot. 137. Ann. 156. Aceph. 191. Ceph’r.
216. Ceph’d. 251. Crus. 282. Arach. 309.
Ins. 340.

muscular. Inf. 7. Pol. 29. Acal. 57. Ech.

76. Hel. 102. Turb. 122. Rot. 132. Ann.
144. Aceph. 176. Ceph’r. 204. Ceph’d.
236. Crus. 267. Arach. 298. Ins. 325.

nervous. Inf. 9. Pol. 33. Acal. 59. Ech.

79, 80. Hel. 104. Turb. 123. Rot. 134.
Ann. 146, 147, 148. Aceph. 181, 182, 183.
Ceph’r. 206, 207, 208. Ceph’d. 239, 240, 241.
Crus. 270, 271, 272. Arach. 300, 301. Ins.
328, 329, 330.

respiratory. See Respiratory Apparatus.

splanchnic. See Splanchnic Nerves.

tegumentary. 6ee Cutaneous Envelope.

T.

Taste. See Organs of Taste.

Teeth. Ech. 84. Hel. 108. Rot. 136. Ann. 153.

Ceph’r. 213. Arach. 306.

Tentacles. Pol. 36. Acal. 61. Ech. 83, 91.
Turb. 125. Ann. 149. Aceph. 173, 177, 185,
189. Ceph’r. 204, 210. Ceph’d. 243.
Testicles. Pol. 44, 47. Acal. 68. Ech. 97. Hel.
115, 116, 117. Turb. 128. Rot. 140. Ann.
166, 168. Aceph. 198. Ceph’r. 228. Ceph’d.
259. Crus. 291, 293. Arach. 316. Ins. 362.
Tongue. Ceph’r. 213. Ceph’d. 244, 248. Ins.
333, 337.

Tracheae. Ann. 159. Crus. 287. Arach. 312.
Ins. 342.

Tube, anal. Aceph. 189, 194.

buccal. Aceph. 189, 194.

germinative. Hel. 118.

digestive. Inf. 12. Pol. 37, 38. Acal. 61.

Ech.k 85. Hel. 106, 107. Turb. 125. Rot.
136. \ Ann. 154. Aceph. 189. Ceph’r. 214.
Ceph’d. 249. Crus. 279. Arach. 307. Ins.
338.

Tubes, calcareous. Ann. 161.

genital. Hel. 117.

respiratory. Rot. 138. Aceph. 193. Ins.

343.

trachean. Ech. 93.

Tunnel. Ceph’d. 234.

Tcjrbellaria, 120.

U.

Uterus, nel. 115, 116, 117. Aceph. 199. Ceph’r.
227, 228.

V.

Vagina. Hel. 115, 116, 117. Turb. 128. Ins.

351. See also Genital Orifices.

Veins. See Circulatory System.

Vesicles, pedunculated. Hel. 112.

of Poli. Ech. 92.

seminal. Hel. 115, 117. Turb. 128. Ann.

166. Ceph’r. 227. Arach. 319. Ins. 352.
See also Receptacula Seminis.

tentacular. Ech. 83-

Vessel, dorsal. Ann. 156. Crus. 283. Arach.
309. Ins. 340.

Vessels, aquiferous. Ann. 159. Aceph. 195.
Ceph’r. 222. Ceph’d. 254. See also Aquifer-
ous System.

lateral. Ann. 156.

Malpighian. Crus. 288. Ins. 345.

ventral. Ann. 156.

Vulva. See Genital Orifices.

W.

Wax. Ins. 347.

Wings. Ins. 326.

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