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CHARLES DARWIN

(From a photograph, 1881, by Messrs. Elliott and Fry)

ae

q THE

ANATOMY OF THE FROG

-

BY

Dr. ALEXANDER ECKER

PROFESSOR OF HUMAN AND COMPARATIVE ANATOMY
IN THER UNIVERSITY OF FREIBURG

Transfated, with numerous Annotations and Additions

BY

GEORGE HASLAM, M.D.

SCIENTIFIC ASSISTANT IN THE MEDICAL DEPARTMENT IN THE UNIVERSITY
OF ZURICH ; FORMERLY ASSISTANT LECTURER IN PHYSIOLOGY IN THE
OWENS COLLEGE, VICTORIA UNIVERSITY, MANCHESTER

ILLUSTRATED WITH MANY WOOD ENGRAVINGS

AND TWO COLOURED PLATES EXECUTED BY HOPMANN, WiURTZEURG, BAVARIA

Orford
AT THE CLARENDON PRESS

—

haa SEEN BY

[All rights reserved | PRESERVATION

SERVICES

DATE. htt DlatistaAclediat ltd

TRANSLATOR’S PREFACE.

I wunpertook the publication of a translation of Ecker’s
‘Anatomie des Frosches’ at the suggestion of Professor A.
Gamgee while I was working under his superintendence in the
physiological laboratory of the Owens College. The work was
subsequently accepted by the Delegates of the Clarendon Press; as
one of the series of ‘ Foreign Biological Memoirs,’ published by them. _
Early in the progress of the work it became evident that a mere
translation would be unsatisfactory, and that it would be desirable
to recast and modify several portions of the book. It was deemed
advisable to give greater completeness to the work by descriptions
of the minute structure of the several organs. For these purposes
the appearance of the work has been unavoidably delayed. ;

I have done my best to bring the book up to date by including
the results of recent researches, to which I have added many facts .
derived from my own personal investigations. All such additions
are enclosed within square brackets [ |. More than a hundred
new figures, of which one-third are original, have been added ; and
copious, though it is feared still incomplete, lists of references to
frog-literature have been drawn up. By these additions the size
of the book has been considerably increased.

Tn the several sections into which the book is divided the following
points may be more particularly noticed :—

Sect. I. The Bones and Joints. The nomenclature of Parker

and Bettany has been adopted throughout.

Sect. II. The Muscles. This section remains in its original form,

Sect. III. The Nervous System. The chapters on the central

a3

vi TRANSLATORS PREFACE.

nervous system and the sympathetic system have been re-
written. The description of the arteries of the brain is
entirely new, while the chapters on cranial and spinal nerves
have received many smaller additions, and have been re-
arranged to facilitate reference.

Sect. IV. The Vascular System. The chapter on the heart is
practically new, and many additions and alterations have
been made in the descriptions of the blood-vessels and
lymphatics.

Sect. V. The Alimentary Canal, with its appendages, the Spleen
and the Peritoneum. In this section much new material has
been added : the descriptions of the blood-vessels of the liver, ©
the ducts of the liver and pancreas, ete., being the results of
original investigation.

Sect. VI. The Respiratory Organs, the Thymus and Thyroid
Glands, These organs have been carefully studied and
numerous new details are noted. The lymphatic glands of
the hyoid region have, after some hesitation, been designated
tonsils,

Sect. VII. The Urino-Genital Organs. A very large number
of preparations have been made to investigate the vessels and
uriniferous tubes of the kidneys; and the descriptions of
the remaining organs of this section have received large
additions from recent publications.

Sect. VIII. The Skin and the Sense-Organs. This section has,
with the exception of very small portions, been re-written and
very much enlarged.

Before concluding this preface, I must thank my friend Professor
A. Milnes Marshall, of the Owens College, for all the help and
kindness he has extended to me before and during the time this
work has been in hand; to him I am indebted not alone for the
loan of books, pamphlets, ete., and for much useful information,
but also for the care and patience with which he has read and
corrected the whole of the proof-sheets.

To Professor G. Lunge, of Ziirich, I am indebted for the use of
the library of the Gesellschaft der Naturforscher of Ziirich ; and

TRANSLATOR S PREFACE. vii

to my friend Mr. C. Herbert Hurst, of the Owens College, for the
drawings for figures 132, 133, 134, and 136; also to Dr. Max
K6ppen, of Strasburg, for the proof-sheets of his valuable paper,
‘Zur Anatomie des Froschgehirns’: to these gentlemen I beg to
express herewith my heartiest thanks. Lastly, I must express my
sense of indebtedness to the Delegates of the Clarendon Press, who
have kindly allowed me to alter the original plan of the book, and
to make extensive additions far beyond the limits originally
intended.

A second edition of the original German work is in course of
publication. The first part, on the bones and muscles, has already

appeared.
GEO. HASLAM.

Zitnicu, 1888.

PREFACE TO THE FIRST PART.

—— +4 ———

THE idea of this manual on the anatomy of the frog, of which I
now offer the first part to physiologists and to those who would
become such, occurred to me during the preparation of the plates
for my ‘Icones Physiologicae.’ I was then convinced of the
necessity of such a book. I regret that many direct and indirect
causes have hindered its earlier completion ; fortunately, however,
its appearance is still opportune, as the need for the book has not
diminished. I am conscious that the book requires a recommenda-
tion to the indulgent judgment of my fellow-workers, since almost
every one has studied the frog for one purpose or another, and
each will closely criticize in that department with which he is most
familiar. Although I shall not be able to satisfy all, still I hope
that my work may serve as a useful basis for further investigations,
and I would apply to it the words with which Sémmering’ prefaced
his anatomy: ‘Ich winschte ein Handbuch zu liefern und seine
Einrichtung so zu treffen, dass man kiinftig an ihm als einer Basis
nach Erforderniss leicht andern, wegnehmen und zusetzen kénnte !’

Lest more be anticipated from the book than it is intended to
supply, I would observe that I have throughout had in mind only
a descriptive anatomy of the indigenous (German) frog; a com-
parative anatomy of Batrachians was as foreign to my intention as
were developmental or histological questions : hence morphological
details must not be expected. Any hope of formulating a systematic
nomenclature of the muscles has been abandoned; as neither one
based upon their mode of action, of which we know so little, nor
one based upon their origins and insertions, as demonstrated by
the unpronounceable names of Chaussier and Dugés, is really
practicable. I have therefore preferred to avail myself, as far as
possible, of the received names, which have been chosen partly

1 «J wished to furnish a manual so arranged that it might serve as a basis easily
altered, pruned, or enlarged as the future might need.’

PREFACE TO THE FIRST PART. 1X

according to mode of action, partly according to origin and
insertion, and partly according to position and form ; while in the
choice of new names I have given preference to the simplest.

The figures are, with few exceptions, original, and drawn by
myself, Their careful execution in woodeut has added a very
necessary neatness to that correctness, which alone I claim as mine.

ALEXANDER ECKER.

FREIBURG,
February, 1864.

PREFACE TO THE SECOND PART.

SIXTEEN years have elapsed since the first portion of this
anatomy of the frog appeared; this second portion, therefore,
requires a somewhat apologetic introduction.

The nervous and vascular systems have, in substance, been
known for some years; still, certain points required a thorough
revision : this seemed especially necessary with regard to the cranial
nerves. In consequence of my anthropological investigations, and
particularly through undertaking the editorship of the ‘Archiv fiir
Anthropologie,’ my attention was drawn into another channel, and
I found it impossible to work out this chapter: consequently the
whole was deferred, and would have been still longer delayed had I
not received assistance.

At my request Professor Wiedersheim undertook to imvestigate
afresh the cranial nerves, the brain, the spinal cord, and the sympa-
thetic system ; and the descriptions of these parts are the result of
his work alone. I regard it as most. advantageous to this second
part that so experienced an investigator in the anatomy of Amphibia
should have given me his help.

The remaining portions appear almost unaltered as written
several years ago; and the majority of the illustrations date from

x PREFACE TO THE SECOND PART.

the same period. I had neither the time nor the zeal necessary to
re-examine the whole; besides, it is doubtful whether eyes some
twenty years older would improve matters.

This somewhat neglected book is therefore commended to the in-
dulgence of my fellow-workers, with the hope that it may at least
form a basis upon which further work may easily be done ; to proffer
more than this, as I stated, with a quotation from Sémmering,
in the preface to the first part, I have never even hoped.

The final part of the work, on the viscera and sense-organs, has
been undertaken by Professor Wiedersheim, and will appear in the
Spring of 1882.
ALEXANDER ECKER.

- FREIBURG,
August, 1881.

CONTENTS.

INTRODUCTION
Section I. Tue Bongs and JOINTS
“ IJ. THe Mescies .
» III. THe Nervous System
» LV. THe VascuLaR System. . a .
V. THe ALIMENTARY TRACT WITH ITS APPENDAGES, THE SPLEEN, AND
THE PERITONEUM y ‘i : J =

» WI. THe Larynx, Lunes, Vocat Sacs, ToyMus AND THYROID GLANDs,
AND THE LyMPHATIC GLANDS (TONSILS?) OF THE Hyorp

REGION . ‘ : é i “ re
» WII. Tse Urino-GeniraL SysTEM, THE ADRENALS, AND THE Fat-
. Boprgs . ‘
‘ ,
» VIII. THe SKIN AND THE SENSE-ORGANS s : :
ADDENDA, ETC. . : 3 3 3

INDEX é

ILLUSTRATIONS.

FIGURE PAGE

| er Z 4
2. The Brown grass-frog, Ranatem-
poraria, L. . . .
3. Femur of Rana esculenta . - 16
4. Vertebrae of do. $ Say
5. Vertebral column ofdo. . . 18
6, 7. Section through a vertebra of
Rana esculenta . : - 20
8; 9. U: of Rana esculenta. 21
10-14. Skull of do. - 22, 23, 25, 28
15. Nasal Cartilages of frog . - 29
16, 17. ren Rana esculenta 29, 30
18. Origin of suspensory cartilage
from the skull . ~ = 32
19, 20. Skull of Rana esculenta 325 33
21. Mandible of Rana esculenta 34
22. Hyoid of Rana esculenta 35

23. Omosternum of Rana esculenta 36
eee ee eee

2 36
25. Shoulder-girdle of the frog 37
26, 27. an of Rana es-

8
28.- SA pec EE PEC 33
29. Seapula seen from behind a ee
30. Left coracoid . 3 ey
81. Clavicle of the left side . 39

32. ee te
88. Hinder border of the scapula x
and coracoid . 40

34. Clavicular cartilage of ‘Rana
esculenta 40

35. Humerus of Rana esculenta
(female) . . 41
36. Do. (male) 3 41
37. Do. (female) . Bee

hand of Rana esculenta <<
ee Pelvis of Rana esculenta .
43. Horizontal section through the
iliac bones, ete. . - 49
44. Femur of Rana esculenta 7-4
45. Tibio-fibula of do. . : => ko
46. Section of the tibio-fibula - 50
47. Right foot of Rana esculenta . 51
48-50. Eye-muscles of do. . 55, 56
51. Skull and orbital cavities of
Rana esculenta . : Rey

PAGE
"52. SM. levator bulbi of Rana es-

culenta 57
53. Eye-muscles of Rana esculenta 58
54. Facial muscles of do. ¢ 59

55. Muscles of the back and shoul-
der
56, 57. Muscles of the lower j jaw of

Rana esculenta . ot Gx
58. Muscles of the throat, chest,

and abdomen of do. . 63
59. Muscles of the hyoid bone and

the tongue of do. : 2
60. Do. (from below) . ao ts Oe
61. Do. (from right side) a 66

62. Muscles of the throat, chest,
and belly of Rana esculenta 68

63. Muscles of trunk of Rana es-
culenta (from the right side) 69

4. Second layer of abdominal mus-

cles of Rana esculenta, from
right side and below - ge
65. M. obliquusinternus . 71

66. Muscles of the back and shoul-
der blade . 72

67. Muscles of the back and pelvic
girdle of Ranaesculenta ~. 74

68. Muscles of the shoulder, from

below .
69. Muscles of the right shoulder
and u arm 78

70. Right shoulder, from below. 79
71. Muscles of the back and shoul-
der. 79
94° Wgkslin of tha cheek; Threat,
and belly of Rana esculenta 81
73. Muscle of Tight shoulder and

upper arm 83
74. Muscles of the right arm of
Rana esculenta . “ - 84
75. Do. (deep layer) . 85
76. Muscles of forearm of Rana es-
culenta 2
77. Muscles of hand of Rana es-
culenta, volar surface . . 88

78. Second layer of muscles on
volar surface of hand of
Rana esculenta . 88

79. Muscles of hand of Rass €3-

culenta -
80. Muscles of left thigh ans. . 95
$1, 82. Do. (ventral surface). 98, 99

X1V

FIGURE
83. Deep muscles of left thigh yi
Rana esculenta .
84. Do. (Dorsal view) . - ;
85. Left half of pelvis of Rana es-
culenta
Muscles of the right leg and
foot of Rana esculenta (Dor-
sal view) . ; “
87. Do. (seen from below) é :
88. Do. (Dorsal view) . :
89-91. Muscles of the plantar sur-
face of foot of Rana escu-
lenta . 107, 111,
92-94. Dorsal view of muscles of
foot of Rana esculenta
115, 117,
95. Pectoral region of Rana es-
culenta :
. Hind portion of back and ‘thigh
of Rana esculenta
. The nervous system of Rana
esculenta, from the ventral
surface
. Dorsal view of brain of Rana
esculenta
. Transverse

86.

section through

hinder end of Medulla ob-_

_ longata °

100. Do. at the point of origin of
the abducens nerve

Do. of the auditory nerve

Ventral view of brain of Rana
esculenta.

Lateral do.

Transverse section through the
anterior portion of the optic
lobes opposite the origin of
the motor-oculi nerve.

105. Horizontal section through the

_ brain to show the ventricles
106. Section through the lower di-
vision of the pituitary body

107. Transverse section through the
hinder portion of the cere-
bral hemispheres

Transverse section near the
middle of the cerebral hemi-
spheres ‘ -

From a transverse section
through one of the cerebral
hemispheres

Diagram to show the “Vena
spinalis posterior, etc. ,

Dorsal view of the orbit, ete.
(deep dissection) (colowred)

101.
102.

103.
104.

108.

109.

110.
111.

» 100

IoI

112

118

. 119

- 144

- 145
. 146

- 149

150

159

- 164

Plate I.

112. Do. (superficial do.) (colowred)

Plate I.

113. View of roof of mouth; mu-

cous membrane,etc.(coloured)

Plate I.

114, Lateral dissection of head, etc.

(coloured)

Plate I.

ILLUSTRATIONS.

FIGURE PAGE
115. Dissection of the floor of the
mouth (coloured) Plate I.
116. Right half of skull of Rana es-
culenta 174
117. The nervous system of Rana
esculenta, from the ventral
surface 5 176
118. Ventral view of the brain and
spinal cord, to show the
points of exit of the spinal
nerves 178
119. Ventral view of the spinal
ganglia ; - 179
120. Schema of spinal ganglion - 179
121. Dorsal branches of the =
nerves - 181
122. The brachial plexus . - 184
123, 124. Nerves of the ventral sur-
face of the arm . . 185, 186
125. The N. radialis : 186
126. Ventral view of the brain and
spinal cord . : - 188
127. The sciatic plexus 3 . 190
128. Distribution of the sciatic nerve 193
129. Nerves of the leg and sole of
the foot . 194
130. Distribution of the N. peroneus 196
131. Sympathetic cord . 198
132. The heart and blood-vessels,
seen from me ventral sur-
face 522
133. The heart, seen 1 from above. 214
134. The frog’s heart, seen from the
ventral surface 2 215
135. Dissection of a case in which the
auricular septum is placed
more to the left than is
normal 215
136. Dissection of the heart from the
left side 216
137 I. Transverse section through
the junction of the hinder
and middle thirds of the
ventricle of R. temporaria . 217
137 II, Tranverse section through
junction of the middle and
anterior thirds of the same
heart . Z r 217
138. Portion of a transverse section
through the middle of the
ventricle of R. temporaria . 218
139. Course of the cardiac nerves in
the auricular septum . . 219
140. Group of nerve-cells on the car-
diac nerve, from the auri-
cular septum . 220
141a, Small group of nerve-cells from
the auricular septum . 221
141b. Isolated nerve-cells from frog’s 8
heart . : 221
142. Arteries and veins of the
Truncus arteriosus of Bu/o
vulgaris 4 . 222

ILLUSTRATIONS.

PAGE
13. Bebonn of the arterial system

of Rana esculenta . - 223
144, Right carotid gland ‘ . 224
145. Arterial system of Rana escu-

lenta . 225

146. Transverse section ‘at level of
e larynx . 226
147. Dissection to chow the occipito-
vertebral and the cutaneous
arteries. 2 - . 227
148. Branches of the occipito-verte-
bral and cutaneous arteries
; in the head t
149. Dissection to show the occipito-
vertebral and the cutaneous
arteries. F : - 229
150. Subclavian artery of the left
side . . = . 231

. 228

. 232
152. Arteries of the dorsal surface of
the hand

153. Arterial system of Rana escu-
lenta . - 234
154. The

232

nital arteries - 235
155. Bifurcation of the aorta and the

iliac arteries - 236
156. Arteries of the hinder ex-

tremity 237
157. ‘Ariat of the dorsal surface of
thefoot . - 239
158. Arteries of the sole of the foot 240
159. Schema of the veins of Rana
esculenta . ‘ = 242
160. Distribution of the imternal
jugular vein and the an-
terior portion of the cuta-
neous vein.
161. The anterior caval vein and its
branches e
162. Course of the gubaneous vein as
' geen from the side
163. Veins in the region of the
kidne ‘

164.
165.
166.

167.
168.
169.

- 243

- 245

y
Veins of the liver . F
Veins of the hinder extremity .
Transverse section of a septum
with the attached skin
The sinus abdominalis lateralis 252
Sinus thoracicus transversus .
The lymph-sacs of Rana escu-
lenta (seen from the dorsal
surface) . * A ;
170. Do. (seen from the ventral do.) 256
171. Do. (seen from the side) .
172. Transverse section through the
— in the region of the
ymph-sac .
173. Danas to show the iliac
lymph-sac .
174. Plan of attachments of the in-
ferior femoral etc. septa . 259
175. Transverse section of the thigh 260

= 459

XV
FIGURE PAGE.
176. The anterior lymph-hearts . 261
177. The posterior lymph-hearts . 261
178. The roofofthe mouth . . 276
179. The floor of the mouth . ey is

180. The capillaries of the sub-
mucous layer (colowred) Plate IT.

1811. Transverse section of the pre-

bone, to show at-

tachment of the teeth . - 279
181 If. Dentine and enamel - 279
181 IT. Enamel - 279

182, 183. Muscles of the tongue 281, 282
184. The alimentary canal . . 283
185. The abdominal viscera of Rana

esculenta . 284
186. Longitudinal folds of stomach
of Rana temporaria - 285

187. The cells at the mouth of the
gland of the fundus of the
stomach . (coloured) Plate II.

188. The mucous membrane of the
pyloric end of the stomach of
Rana esculenta . R . 286

189. Mucous membrane of the
pyloric end of stomach and
duodenum . - 288

190. Isolated fold of mucous mem-
brane of small intestine of

Rana temporaria - 291
191. Fold of mucous membrane of

Rana temporaria = - 291
192. The large intestine of Rana

temporaria : ° - 292
193. yest intestine of Rana escu-

: ; d oes

194. The liver : oe
195. The and bile-canals . ee
196 L. The hepatic veins

196 IL at i gon Plate IT.
e tic arteries

ne ; (coloured) Plate 1.

197. Liver-cells . a - 299

198. The bile-capillaries - site ae

199. The pancreas and bile-canals . 300

201. The peritoneum of Rana escu-

lenta - 305

202. The position and relations of
the larynx 311

. The cartilaginous skeleton of
the larynx . a3 2)

204. The larynx and surrounding
parts . : : ~ - 313
205. The muscles of the larynx et

206. Three sections through the la-
rynx of Rana esculenta . 316
207. The Rima glottidis - 317
208. The lung of Rana temporaria
(coloured) Plate IT.
209. The vocal sac of the right

side . ; - 320
210. The thymus gland * 321
211. The hema, “— of Rana

_ esculenta . - 321

XV1 ILLUSTRATIONS.
.FIGUR PAGE | FIGURE PAGE
212. The thyroid gland of Rana 237. Various parts from the fungi-
esculenta . 323 form papillae . 381
213. The lymphatic gland of Rana 238, 239. Frontal sections through
* esculenta . . » 324 the nose of two tadpoles. 384
214, The male urino-genital organs . 331 | 24014. Bowman’s glands in situ
215. The right kidney . ; aa from Rana temporaria - 386
216. The blood vessels and lym- 240 IB. Section of Bowman’s gland 386
phatics of the kidney . - 333 | 240 II. Vessels of nasal mucous

217. Vertical sections through the
kidney (coloured) Plate II.
218. The uriniferous tubes. 335
219. A gold preparation of the kidney
of Rana esculenta
(coloured) Plate II.
220. Transverse section of the pieney 338
221. The bladder . ‘ - 339
222. The male reproductive organs . 341
223. Various preparations from the
testis . + 342
224. The female reproductive organs 344
225. Preparations from ovary and
oviduct si * i . 346
226. The male urino-genital organs 348
227. The fat-body of Rana esculenta 349
228. The epidermis from the head of

Rana esculenta . . 36
229. Vertical section through the

skin of the back . 5 - 368
230. Surface view of epidermis of

Rana temporaria : - 368

231. Nerve terminations of the
branched pigment-cells of

the cutis. - 368
232. The temporary papillae i in Rana
temporaria . - 371

233. The epidermis of the supple-
mental toe of Rana eseu-
lenta . 375
234 I. Fore-foot of a male frog - 375
234 II. The swelling on the supple-
mental toe of amale frog . 375
235..The blood-vessels and lym-
phatics of the skin. 376
236. Lateral ee of tadpole
of frog : - 378

membrane of Rana esculenta 386
241. Separations from the olfactory
mucous membrane of Rana

temporaria . - 388
242. The . tympanic membrane of

Rana esculenta . . - 389
243. The columella : . - 391

244. Antero-posterior section thro ~
the capsule of the right
labyrinth of Rana esculenta 392

245. The membranous labyrinth of
Rana esculenta . 39.

246. Part of the outer wall of the

perilymphatic space . + 395

247,248. The right membranous
labyrinth of Rana esculenta 397

249, 250. The membranous labyrinth
of Rana esculenta + 399, 401

251. Preparations from the ear of
Rana esculenta . . - 402

252. The nerve-terminations in the
membranous sg i of
Rana esculenta . - 404

258. Endothelium from the inner
surface of the sclerotic coat . 406

254, 255. Preparation from cornea of
Rana esculenta + 407, 408

256. Thevesselsofthechoroidandiris 410

257. Fibres from the lens of the frog 414

258. Vertical section through retina

of frog - 415
259. Various preparations from the
eye of the frog - 417

260. The vessels of the vitreous body 421

261. Preparations from the nicti-
tating membrane of Rana
esculenta . ; ; . 423

INTRODUCTION.

THERE is no occasion, now-a-days, to offer a lengthened apology
for devoting a treatise solely to the anatomy of the frog, which enjoys
the doubtful honour of being, xar é£0x7v, the physiological domes-
tic animal. It is kept in every physiological laboratory, and is daily
sacrificed in numbers upon the altar of science. The physiologist
has recourse to it, not only to obtain answers to new questions, but
for the sake of demonstrating easily and quickly the most im-
portant known facts of the science. These unlucky batrachians are
to be had in any number, and are specially adapted for experimental
investigation: they have consequently fallen under a harsher tyrant
than the stork in the fable, and their prophetic outcry in the
frog-chorus of Aristophanes, dewa zeicdperOa, has been literally
fulfilled.

As the history of the most important physiological discoveries is
closely related with the employment of the frog in physiological
research, it will not be without interest to review briefly the
history of its use in scientific, especially in physiological, investi-
gations, and to record the services which it has already rendered
to science. Swammerdam (1637-1685), as du Bois-Reymond justly
remarks, was the first to make known the frog as an important
means of research; he says concerning it:—‘ An den Thieren, die
das heisseste Blut haben, ist die Bewegung der Muskeln nicht so
merklich oder hilt vielmehr nicht so lange an, als an Thieren die
mit kilterem Blute begabt sind. Dergleichen sind die Fische und
viele andere Wasserthiere, wie auch solche, die so wohl im Wasser als
auf dem trocknen Lande leben kénnen. Deswegen habe ich inson-
derheit mit dem Frosch meine Versuche angestellt. Denn an diesem

Thiere sind die Sehnen sehr sichtbar und lassen sich leicht entdecken
“> B

eEEOOO

eee eS ee ee

SE. - — aS

2 INTRODUCTION.

und entbléssen'’? Swammerdam made the earliest experiments on
the contraction of muscle by means of chemical and mechanical
stimulation of its nerves; thus laying the basis of our present
nerve and muscle physiology, which has been built up within rather
less than two hundred years; though during the first half of this
period but little advance was made.

From the famous September evening of the year 1786, on which
Galvani first observed the twitchings of a frog’s lee suspended by a
metallic hook to an iron balcony, the frog has, down to the present
time, afforded almost the only material for the investigation of the
excitability of nerve and its associated electromotive changes, and also
no inconsiderable part of the remaining nerve and muscle physiology.
It was not until Miiller devised the method of operating on the
frog that Bell’s law became capable of easy proof; and much of
our knowledge of the functions of the spinal cord is derived from
experiment upon it. Again, the muscles of frogs served, from the
time of Swammerdam to that of Eduard Weber and his followers,
for the investigation of the phenomena and the conditions of con-
traction; and in almost all other branches of physiology there are
important doctrines which were first definitely established by experi-
ment upon the frog. But for the web of the foot of this animal (and
the gills and tail of its tadpole, in which Leeuwenhoek ? describes
the phenomena most clearly) we should not, perhaps for a long
time, have arrived at a satisfactory knowledge of the existence
and the conditions of the capillary circulation. As is well known,
an accurate acquaintance with the constituents of the blood directly
concerned in nutrition has been obtained by observation on the
frog, as well as important facts in the physiology of the blood and
lymph, such as the intimate knowledge of the corpuscles of both
fluids, and the coagulability of the plasma; while in no less degree
have experiments on these animals served to establish the laws of
the heart’s action. Moreover, physiology is not the only science
indebted to the frog: in histology many important results have
been obtained from observations on it, and for histological in-
struction it is now indispensable. To it we owe much of our

1 ¢Tn animals with warm blood the action of the muscles is neither so apparent
nor so long continued as in those animals which have cold blood, such as fishes and
many other aquatic animals, and those also which live both in water and on dry
land. On this account I have made my investigations chiefly on frogs, for in them
the nerves are very distinct, and are easily found and exposed.’ Buch der Natur,
Leipzig, 1752, p. 330.

2 Leeuwenhoek, Arcana Nature ITI, epist. 65 ad Reg. Soc. Lond., p. 158.

INTRODUCTION. 3.

knowledge of the structure of nerve fibres, their origin and termina-
tion, especially in muscle, their relations within the ganglia, and
even the structure of muscular fibre itself. For the study of
reproduction and development the frog has, next to the chick,
afforded the most important material: one need but refer to the
investigations on impregnation from the time of Spallanzani to
that of Newport’, the phenomena of cleavage, and many others.

Thus with progress of time the field in which the frog has been
submitted to observation and experiment, whether for the demon-
stration of established facts to students or for the solving of new
problems, has vastly increased, and this batrachian has indeed be-
come, as we have stated, the physiologist’s domestic animal.

That, for these manifold uses, a more exact anatomical know-
ledge of the frog is very necessary is self-evident. The majority of
students commencing the study of physiology have little more than
a superficial knowledge of the sciatic nerve and: the leg-muscles ; at
most, of the spinal cord and its nerve-roots ; and only acquire any
further knowledge in a disconnected manner. For this they can
searcély be reproached, the literature of the anatomy of the frog
being so widely scattered in monographs and journals that reference
to it involves the expenditure of much time. This attempt, there-
fore, to produce a complete anatomy of the frog, based throughout
upon my own observations, cannot be considered superfluous ; it is
rather to be feared it may be thought insufficient.

The European frogs* alone are treated of in the following
description, 7.e. the two species, Rana esculenta, L., and R. tempo-
raria, lu., the former being more particularly described, though
such differences in structure as occur are noted. This is not
the place to discuss the exact systematic characters of the two
species, yet they cannot be ignored entirely. The species were,
from their habitats, long ago distinguished by C. Gessner*, and
named Rana rubeta, s. gibbosa, the garden or grass-frog, and Rana
aquatica, 8. innoxia, the water-frog ; at least, from his figure, the
former can be no other than R&R. temporaria, though Gessner,

1 It may be well to remind the reader that this introduction was written in 1864.

2 For purposes of comparison other than European frogs were examined, especially
American species of Rana, for which I am indebted to the kindness of my much
esteemed friend Agassiz. These were Rana Catesbyana, Shaw (2. mugiens, Catesby—
R. pipiens, Harlan); R. sylvatica, Leconte; R. clamitans, Daudin; R. palustris,
Leconte ; R. halecina, Leconte. To these, however, no further reference will be made
in the text.

3 ©. Gessner, Thierbuch. Ziirich. Fol., p. 157.

B2

4 INTRODUCTION.

probably expecting to find in it the rubeta of older writers, adds
that it ‘ist fiir giftig zu halten.’
Leeuwenhoek? also, correctly distinguished between them, but it
is to Résel? that we are chiefly indebted for a careful discrimination
and an accurate knowledge of the life-histories of the two species.

The green water-frog, Rana esculenta, L.

' Rana esculenta, L. The green water-frog, Fig. 1, usually attains
a larger size * and is more active than the other species, and for this

1 Leeuwenhoek, Arcana Nature, Vol. ITI of Ecker’s edition. Leyden,1722. Epist. 65
ad Reg. Soc. Lond., p. 154.

2 Résel, Naturgeschichte der Friésche Deutschlands, ed. Schreber. Niirnberg, 1815,
p- 36.

° The extreme sizes are much more pronounced in this species. I have never found
R. temporaria of the size attained by large specimens of the water-frog.

INTRODUCTION. 5

reason is better adapted to the purposes of the physiologist; hence
I have chosen it for description.

The head is flat, as broad as it is long, and triangular with an
obtuse snout in front. The upper surface of the head, i.e. the
space between the eyes, is slightly concave, grooved, and narrower
than in BR. temporaria. The tympanic membrane is circular, and
relatively to the eye is larger. The upper eyelids have several trans-
verse folds in their hinder part. The pupil is oval, with the long
axis horizontal. The vomerine teeth are arranged in two clusters,
which are relatively larger than in R. ¢emporaria and lie exactly
between the posterior nares, without however touching . them.
The openings of the Eustachian tubes do not exceed in size the
posterior nares to so great an extent as they do im R. temporaria.
The male possesses a vocal sac on either side, which reaches the sur-
face beneath the tympanic membrane through a cleft placed behind
the angle of the mouth, and is, in well-developed specimens, about
the size of a cherry. The hind limbs are relatively longer. The
toes are long, and taper towards their tips: the webs between the
toes are cut out semicircularly, and that of the longest or fourth
toe is continued to the tip of the last phalanx. The supplemental
toe is an oval prominence of cartilagimous hardness. The skin
of the back has wart-like tubercles arranged longitudinally in
raised lines; one of these lines runs on each side from the posterior
eanthus as far as the thigh, and is very constant: in the male
a second line surrounds the posterior margin of the vocal sac;
a corresponding line exists in the female.

The skin of the belly is quite smooth, the colour presenting
many variations which appear to depend upon very diverse circum-
stances. It varies with changes in the physiological condition of the
animal. Von Wittich? has shown that a bright green specimen
changes to a dark leafy green colour on exclusion of light; also, that
dark specimens become almost a lemon-yellow colour on exposure to
bright sunlight; and he has pointed out that this brightening of
the skin is an active condition dependent upon contraction of the
stellate pigment-cells. It is therefore not surprising, as the same
inquirer observes, that one should sometimes find specimens of
R. esculenta in which the ground colour is almost a greenish yellow
(as in Résel’s figure, Pl. XIII), whilst in others it can only be

distinguished from the dorsal black patches by a faint greenish

: Von Wittich, Miiller’s Archiv, 1854, p. 41.

6 INTRODUCTION.

shade. There is no doubt that difference of habitat influences the
colour; but this may again be modified by light4, as has been
established in the case of fish by direct observation®. Apparent
varieties may thus occur.

In frog-tanks such diversities of colour may not unfrequently be
observed inthe same individual, as for example when the lower part
of the body immersed in muddy water is dark, while the part above
the water is bright. That the process of casting the skin exercises
an influence on the brightness of the colouring is certain, yet there
are, as von Wittich has correctly remarked, other alterations of
colour which are in no way connected with this process, and are
evidently more of a pathological nature; such as when the frog
assumes a dirty green spotted appearance, the green fading more
and more, until all the patches which are usually green appear
of a dirty greyish-brown with a faint bronze shimmer. According
to this author these changes are most readily brought about by
starvation. The dark colour which frogs exhibit after hibernation
is perhaps to be ascribed to the co-operation of several of the causes
mentioned above.

The usual colouring of healthy animals is as follows: the back
is bright green with three golden yellow longitudinal stripes, one
median and two lateral, and a number of irregular brown or black
stripes of approximately uniform width: on the head are a pair of
black stripes which pass from the angles of the eyes across the nares
to the tip of the nose ; now and then the tympanic membrane and
surrounding: parts have also a black patch, as in 2. temporaria :
another black stripe is found on the anterior surface of the arm, in
the region of the shoulder: and on the thighs are black, yellow, and
white mottlings. The whole of the under-surface is white or
yellowish. At times the yellow stripes of the back are wanting or
are indistinct. It has already been mentioned that many varieties
may occur; and these have in all probability given rise to the de-
scriptions of reputed new species, such as 2. maritima, Risso, found
in South Europe; 2. alpina, Risso, found in the high-lying Alpine
lakes ; 2. hispanica of Fitzinger and Bonaparte, and 2. calcarata of
Michahelles, the last three of which certainly cannot be retained. It

1 Lister, On the Cutaneous Pigmentary System of the Frog. Phil. Trans., 1857,
p- 627.

2 Agassiz et Vogt, Histoire naturelle des poissons d’eau douce (Neuchatel, 1839),
Pl. IV, mention that the colour of trout is very variable and that in shaded and
deep-lying brooks and rivers a variety is found which is black.

!
:
d

INTRODUCTION. 7

is not.improbable that the water-frog, which Spallanzani! used in
his experiments on impregnation, was the 2. maritima of Risso. He
says, one must not confound his frog with that which Résel calls the
green water-frog; the former being much smaller, without the three
dorsal golden-yellow stripes, and the spawning season (in Lom-
bardy) occurring during April and May. Rusconi? also describes
two varieties in Northern Italy.

Rana temporaria, L., the brown or grass-frog, is so named from
the large black patch in the temporal region, 7.e. between the eye
and the shoulder. While the separation of the preceding species
into several varieties does not seem to be well founded, it appears
that two distinct species have been included under the name of
R. temporaria. Millet of Angers* first described, in his Fauna du
département de Maine-et-Loire, as ‘grenouille rousse,’ a species
differing from R. temporaria, and gave the species previously known
as LR. temporaria the name of &. flaviventris, ‘ grenouille & ventre
jaune.’ No further notice, however, was taken of this observation,
not even by Duméril and Bibron in their ‘ Erpétologie.” Quite inde-
pendently Steenstrup *, in the year 1846, pointed out that two frogs,
differing in structure and habits, had been confounded under the
name &. temporaria; these he distinguished as R. platyrhinus and
R. oxyrhinus. Von Siebold®, and also Schiff* in part, have confirmed
these statements. My own observations lead me to a like conclu-
sion; I shall therefore distinguish two species, viz.:—(1) Rana
temporaria, Li., Rana platyrhinus, Steenstrup; (2) Rana oxyrhinus,
Steenstrup.

Rana temporaria, L.; Rana platyrhinus, Steenstrup. The brown
grass-frog, Fig. 2, does not attain the dimensions of 2. esculenta, L.,
but is, however, always larger than R. oryrhinus. The head is
somewhat broader than long, and the upper surface of the skull
is not grooved, as in R. esculenta, but is flat. The space between
the eyes is wider (according to Duméril, equal to the width of the
upper eyelid, whereas in R. esculenta it is just two-thirds this

* Spallanzani, Versuche tiber Erzeugung der Thiere und Pflanzen. Leipzig, 1786,

p- 5-

* Rusconi, Développ. de la Grenouille. Milan, 1826, p. 6.

* Annales des Sciences naturelles. Zoologie, IV Série, Vol. IV, 1855, p. 368.

* Amtl. Bericht iiber die 24. Versammlung deutscher Naturforscher in Kiel, 1846,
p- 141; Wiegmann’s Archiv, 1847, Vol. II, p. 341; Steenstrup, Oversigt K. Danske
Selsk. Forhandlgr., 1846, p. 92.

> Wiegmann’s Archiv, 1852, Vol. I, p. 14.

® Annales des Sciences naturelles. Zoologie, IV Série, Vol. IV, 1885, p. 368.

8 INTRODUCTION.

width): the fronto-parietal bones are wide and flat. The tympanic
membrane, in comparison with the eye, is smaller than in 2. esculenta,
and is usually less distinguishable from the surrounding parts as
regards colour and transparency. The apertures of the Eustachian
tubes are, relatively to the posterior nares, larger than in the water-
frog. The vomerine teeth are comparatively small and lie in two
groups placed obliquely to each other, their anterior ends diverging
from each other and being prolonged as ridges to the anterior
margins of the posterior nares. The two groups do not lie between

The brown grass-frog, Rana temporaria, L.

fhe nasal apertures, but behind a line drawn transversely through
their posterior margins. Vocal sacs are absent in both sexes.
-The hind legs are relatively shorter: the toes are not so evenly
tapered off, indeed they are slightly swollen: the fourth toe,
as compared with the third and fifth, is somewhat longer than in
R. esculenta; the web of this toe does not extend to the tip of the
toe, but terminates in both sexes at the last phalanx but one; the
web on the third toe is less developed on the thumb side than
on the other: on the remaining toes also the margins of the web

INTRODUCTION. 9

are less developed than in R. esculenta, so that the free borders
appear more crescentic. The supplemental toe forms only a
soft and inconspicuous prominence. The back is mostly smooth ;
the raised glandular ridge, which extends along each side from
the eye to the thigh, is present, but is much narrower and less
prominent than in AR. esculenta; another ridge passes from the
angle of the mouth to the shoulder. The colouring in general, and
especially the ground colour of the dorsal surface, varies from the
brightest tints to the darkest brown-black ; the conditions causing
these variations being, no doubt, the same as those described above
in R. esculenta. A dark-brown specimen taken from a dark frog-
tank is usually yellowish red on the following day. The black
patch between the angle of the mouth and the shoulder has
given this species the name of 2. temporaria, and is constant. A
black stripe passes from the eye across the nostril to the tip of
the snout, and a similar one is found upon the anterior surface
of the upper arm, .On the hind legs the bands are chiefly trans-
verse. The ventral surface is yellowish, and sometimes spotted.
The thighs have a granular appearance, and these as well as the
belly and the neighbourhood of the anus have frequently a reddish
coloration presenting the appearance of an irritated surface.

Rana oxyrhinus, Steenstrup. This species is always smaller and
more elegant in shape than the preceding one. The head is conical,
with the pomted snout projecting beyond the lower jaw; a feature
which is especially evident on looking from below. The space be-
tween the eyes is narrower than in R. temporaria, and is not
grooved, but convex; the fronto-parietal bones are narrow and
arched. With respect to the arrangement of the vomerine teeth
and the sizes of the apertures of the Eustachian tubes, this species
holds an intermediate position between the other two. Next to
the pointed snout, the greatest difference between this species and
R. temporaria is the presence of a much larger supplemental toe,
which is of cartilaginous hardness, compressed from side to side,
and contains a larger bone’. The vocal sacs are absent. In the
males the web of the longest toe reaches to the last phalanx but
one; in the females, on the contrary, the last three phalanges pro-
ject freely beyond the web. The extremities of the toes are more
pointed than in R. temporaria, in which respect, as also in several

? According to Steenstrup, J. c., the size of the supplemental toe is in R. temporaria
one-half and in 2. oxyrhinus two-thirds of that of the next toe.

10 INTRODUCTION,

others, it approaches A. esculenta. In colouring, 2. oayrhinus re-
sembles 2. temporaria; the throat, however, is usually pure white,
at least in the males, the breast dusky white and spotted, while in
hk. temporaria the throat and breast are more uniformly coloured
and yellowish. V. Siebold has remarked that, during the pairing-
season, the males are covered with a bluish bloom!; and, the
whole ground colour being bright at this period, very beautiful
tints result. V.Siebold? moreover states that the note which the
males produce during the pairing-season is different in the two
species. On the whole, 2. oxyrhinus appears to stand midway
between R. esculenta and LR. temporaria.

Thomas*, in addition, distinguishes another species, 2. agilis,
which however may be the ‘ grenouille rousse’ of Millet. Schlott-
hauber* has described a frog which, in marking and colouring, might
hold a middle place between R. esculenta and R. temporaria; in my
opinion this is probably a cross between the two. That attempts at
copulation are made, despite the difference of the pairing-season, is
well known ; Pontallié® mentions this, and I have myself often found
males of 2. temporaria in conjunction with females of 2. esculenta.

I use the following terminology. I suppose the animal to be in
its natural position, the belly towards the ground, the back up-
wards; a horizontal plane passing from the snout to the anus
divides the body into a superior or dorsal half and an inferior or
ventral half. The terms superior and inferior, dorsal and ventral,
indicate positions with relation to this plane. I call that part
anterior which looks towards the head, and that posterior which
looks towards the anus. A vertical plane at right angles to the
middle of the longitudinal axis of the body, divides it into an
anterior or cephalic and a posterior or caudal half. All sections
and planes which lie parallel to this, as well as this itself, are frontal.
Lastly, by a perpendicular section along the middle line of the body
the animal is divided into right and left halves; this plane is the
median plane; and the position relative to this plane is expressed
by the terms median or lateral. Planes parallel to the median plane
are termed sagittal.

1 T do not find, however, that this disappears when the animals are on land; in
fact I have animals before me in a glass in which it is plainly seen.

A AUsOs5 Pol fhe

3 Annales des Sciences naturelles. Zoologie, IV Série, Vol. IV, 1855.

* Wiegmann’s Archiv, Vol. I, 1844, p. 255.

5 Annales des Sciences naturelles. Zoologie, III Série, Vol. XVIII, 1852, p. 243.

~ SECTION I.

THE BONES AND JOINTS.

—ee ee

THE BONES AND JOINTS.

LITERATURE.

van Altena, Commentatio ad quest. zoologicam in academia Lugduno-Batav.
a. MDCCCXXVIII propositam, qua desideratur ut systematice enumerentur species
indigenz reptilium ex ordine batrachiorum addita unius saltem speciei anatomia
et presertim osteographia accurata. Lugd. Bat. 1829. 4°. With 4 Plates.
Ange, Martin St., Recherches sur les organes transitoires des batraciens. Annales
des Sciences naturelles. 1° Série. Vol. XXIV. 1831.
Bell, Article Amphibia, in Todd’s Cyclopaedia of Anatomy and Physiology. Vol. I,
p. go. 1835-1836.
Born, Dr. Gustav, Ue.d. Nasenholen u.d. Thranennasengang der Amphibien. Leipzig,
1877.
Bench, @. , Beitrage zur Naturgeschichte und Klassification der nackten Amphibien.
Wiirzburger Naturzeitschrift, 1862.
Bruch, G., Neue Beobachtungen zur Naturgeschichte der einheimischen Batrachier.
Wiirzburger Naturzeitschrift, 1863.
Cuvier, Recherches sur les ossements fossiles. Vol. V. Pt. II. Paris, 1825.
Cuvier, Lecons d’anatomie comparée. Paris, 1835. Vol. I.
Cuvier, Ueber die Riickenwirbel der Reptilien und Amphibien, Froriep’s Notizen.
Vol. XIII, p.74. 1826.
Daudin, Histoire naturelle des Rainettes, Grenouilles et des Crapauds. Paris, 1802.
Ducrotay de Blainville, Ostéographie ou description iconographique comparée du
squelette et du systéme dentaire des cing classes d’animaux vertébrés. Paris,
1841.
Dugés, Recherches sur l’ostéologie et la myologie des batraciens & leurs différents
ages. Paris, 1834. 4°. With 20 Plates.
Duméril et Bibron, Erpétologie générale ou Histoire complete des Reptiles. 1836.
Gegenbaur: 1. Ueber Bau und Entwicklung der Wirbelsiule bei Amphibien iiber-
haupt und beim Frosche insbesondere. Abhandlungen der naturforschenden
Gesellschaft zu Halle, Vol. VI. Halle, 1861.
2. Untersuchungen zur vergl. Anatomie der Wirbelsiule bei Reptilien und Am-
phibien. Pt. I. Leipzig, 1862. (Carpus and Tarsus.) With 4 Plates. 4°.
Gegenbaur, Untersuchungen zur vergl. Anatomie der Wirbelthiere. Pt. II.
Schultergirtel. 1865.

Ginther, Ueber geschlechtliche Differenzen in Knochen von lebenden und fossilen
Fréschen und Fischen. Annals of Natural History. 1859. Vol. III.

Hallmann, Die vergleichende Osteologie des Schlifenbeins, ete. Hannover, 1837.
4°. With 3 Plates.

Hoffmann, C. K., Beitriige zur Erkenntniss des Beckens der Amphibien und Reptilien.
Leyden, 1876.

Hoffmann, C. K., Bronn’s Klassen und Ordnungen des Thierreichs, Vol. VI.
Amphibien. Leipzig, 1873-8.

Huxley, On the Theory of the Vertebrate Skull; Croonian Lecture, Proc. Royal
Society, p. 381. 1858.

Huxley, Article Amphibia, Encyclopedia Britannica, [Xth Edition. 1875.

Huxley, Lectures on the Elements of Comparative Anatomy.

Huxley, Handbuch der Anatomie der Wirbelthiere. Deutsche Ausg. von T. Ratzel.
1873.

Kehrer, G., Beitriige zur Kenntniss d. Carpus und Tarsus d. Amphibien, Reptilien,
und Saéuger. Berichte d. naturf. Gesell. z. Freiburg. 1886.

14 THE BONES AND JOINTS. LITERATURE.

v. Klein, Beitriige zur Anatomie der ungeschwinzten Batrachier. Jahres-Heft.
Wiirtemberg, 1850.

Késtlin, Der Bau des knéchernen Kopfs. Stuttgart, 1844. 8°.

Leukart, Zwischenkiefer. Valentins Repertoire. 1841, p. 155.

Marshall, A. M., The Frog. Manchester and London. 2nd Edit., 1885, pp. 45-59.

Mayer, A. F., Beitriige zu einer anatomischen Monographie der Rana pipa. Acad.
Caes. Leop. Nov. Acta. 1825. Vol. XII, p. 527 ; and Isis v. L. Oken. 1825. col. 317.

Meckel, System der vergleichenden Anatomie. II.Thl. I. Abthlg. Halle, 1824. 8°.

Meckel, Ueber das Zungenbein der Amphibien. Meckel’s Arch. f. Physik, 1818.
Vol. IV, p. 60.

Mertens, ‘Anatomia batrachiorum prodromus sistens observationes nonnullas in
osteologiam batrachiorum nostratium. Hale, 1820. 8°.

Mivart, On the Classification of the Anurous Batrachians. Proc. Zool. Soc. 1869.
Morren, Observations ostéologiques sur l’appareil costal des batraciens. Bulletins
de l’Acad. de Bruxelles, 1835, II. —Mémoires de I’Académie, 1837. Tome X.
Miller, Beitrag zur Anat. d. Amph. Zeitschrift f. wissenschaftliche Zoologie.

Vol. TX. 1858, p. 178.

Parker, W. K., Structure and Development of the skull of the common frog. Phil.
Trans.-1871, p. 137.

Parker, W. K., Skull of Batrachia. Phil. Trans. 1876, p. 601.

Parker, W. K., and Bettany, G. T., Morphology of the Skull. London, 1877.

Pouchet, Note sur les différences que le sexe imprime au squelette des grenouilles.
Comptes rendus. Vol. XXV, p. 761. 1847.

Reichert, K. B., Vergleichende Entwicklungsgeschichte des Kopfs der nackten
Amphibien nebst den Bildungsgesetzen des Wirbelthierkopfs im Allgemeinen
und seinen hauptsichlichen Variationen durch die einzelne Wirbelthier-Classe.
Konigsberg, 1838.

Remak, Untersuchungen iiber die Entwicklung der Wirbelthiere. Berlin, 1855.

Résel, von Rosenhof, Historia naturalis ranarum nostratium. Nornberg, 1758.

Rudolphi and Breyer, Observationes anatomicae circa fabricam Ranae pipae.
Berolini, 1811.

Rusconi, Développement de la grenouille commune, Milan, 1826.

Rusconi, Sulle metamorfosi delle osse della testa della rana. Annali di Bologna.
17e Série, Vol. II, p. 357.

Schneider, Historia amphibiorum. Jenae, 1799.

Shaw, General Zoology. London. Vol. II, Pt. I, p. 167.

Stannius, Zootomie der Amphibien (Handb. der Zootomie der Wirbelthiere,
2. Buch). 2nd Edit. Berlin, 1856. 8°.

Stricker, Untersuchungen iiber die Entwicklung des Kopfes der Batrachier. Arch.
f. Anat. u. Physiol. 1864, pp. 52-76.

Stricker, Beitriige zur Biologie der Batrachier. Verhandl. der Wiener Akademie.
1866. Vol. XVI, pp. 451-456.

Townson, R., Facts and Observations in Natural History. London, 1799.

Troya, Recaite sur la structure singulitre du tibia et du cubitus des grenouilles et
des crapauds. Mémoires de mathématique et de physique présentées & l’acad.
de Paris. Vol. IX. 1780.

Wagner, Icones Zoctoniieas: Leipzig, 1841.

Wagner, Lehrbuch der vergleichenden Anatomie. Leipzig, 1834-1835.

Wiedersheim, R., Lehrbuch d. vergleichenden Anatomie der Wirbelthiere auf
Grundlage d. Entwickelungsgeschichte.. Jena, 1886, 2nd Edit.

Wiedersheim, R., Elements of Comparative Anatomy of Vertebrates, translated by
W. Newton Parker. London, 1886,

a i Me i ee

—-vr-”

THE BONES AND JOINTS.

Tue consideration of the differences in form, number, and histo-
logical structure, which the parts of the skeleton present during
the various stages of development does not fall within the scope of
this book: we have here but to deal with the adult frog.

The skeleton is made up of histologically different materials ;
these are:—(1) bone, (2) hyaline cartilage, and (3) so-called cal-
cified cartilage. Concernmg the last it is necessary to make
some observations. I have chosen for it the name calcified car-
tilage in place of the more usual names ‘cartilaginous bone’ or

“primordial ossification,’ as by this term its nature appears to
be expressed without any ambiguity’: it is hyaline cartilage
in which calcareous particles have been deposited to a greater or
less extent: in the fresh state it has the appearance of moderately
firm cartilage; when dry it becomes opaque and white, like the
caleareous crusts on the cartilages of the Plagiostomata. The cal-
careous material is deposited in the cartilage in finer or coarser
granules ; after removal of the lime by means of acids, the cartila-
ginous structure becomes apparent although not so perfectly as in
unchanged cartilage.

This calcified cartilage is widely distributed in the frog’s skeleton :
very many parts, which in higher animals consist only temporarily
of this substance during the transition from cartilage to bone, are in
the frog formed of it throughout life. It is especially well-marked
in the epiphyses of the long bones in the hand and foot, in the
bones of the shoulder-girdle, ete. To avoid repetition later on I will
briefly describe it as found in the first-mentioned situation. Dugés?
has described its external appearance, while Bruch* has made us

1 Compare Miiller, Zeit. f. wissen. Zoolog., Vol. IX.

* Dugts, Recherches sur l’ostéologie et la myvlogie des batraciens & leurs différents

ages, p. 116.
* Bruch, Beitriige zur Entwicklungsgeschichte des Knochensystems. Schweiz.
Denkechriften, p. 118.

\

16 THE BONES AND JOINTS.

acquainted with its histological peculiarities. Ifa long bone of the
frog be dried, the femur for example, the middle part is found to
differ considerably from the epi-
physes in colour and in other par-
ticulars. The shaft alone has the
appearance of bone, the epiphysis
consisting of a white, opaque, firm
substance, resembling plaster of
Paris or lime, but which in the
fresh moist state is exactly like
cartilage. The epiphyses, which
are fitted to the ends of the dia-
physis like the cap of a stick-
handle, have sharply defined mar-
gins (Fig. 3), as is well seen in
Figs. 36, 39, 45, and 46. Ifa sec-
tion be made through the epiphysis
Longitudinal section through the upper ex- and part of the diaphysis, the long
tremity (of the femur of Hana esculenta, tube of true bone is seen to cease
4 Hyaline cartilage (articular cartilage). abruptly above 9; Fig -35 and over

¢ Hyaline cartilage closing end of bony the end of it the epiphysis FZ is
cylinder.

Fig. 3.

c’ Calcified cartilage of epiphysis. fixed. This epiphysis consists al-
D Bony cylinder of diaphysis P

E Epiphysis, — most entirely of calcified cartilage
Degrees bophotd ce’, and has merely a superficial

o End of diaphysis,

layer of hyaline cartilage 4. The
bony eylinder of the diaphysis 0, which contains the marrow J in
its interior, is shut off from the epiphysis by hyaline cartilage, the
cells of which are arranged in transverse layers, 0.

I. THE VERTEBRAL COLUMN.

The vertebral column of the frog consists of ten bones, viz. nine
true vertebrae, and the rod-shaped urostyle, which alone is almost as
long as all the remaining vertebrae.

I. GENERAL DESCRIPTION OF THE NINE VERTEBRAE.

a. The bodies of the vertebrae are compressed from above down-
wards; the posterior surface of each body, with the exception of

THE VERTEBRAL COLUMN. 17

the eighth, presents an articular head covered with cartilage; the
anterior surfaces, with the exception of the ninth, present corre-
sponding articular depressions, covered with cartilage.

b. The arches, which have some-
what sharp margins both before and
behind, bear the following pro-
cesses :—

1. The articular processes (Figs.
4 and 500) are similarly placed
to. those of the dorsal vertebrae of
man: they project horizontally, the
cartilaginous articular surfaces on
the posterior. processes being directed
downwards, those on the anterior

upwards.
2. The transverse processes

(Figs. 4 and 5 #2’) are strong, flat,—

and of very varying size and direction.
The transverse processes of the fourth
vertebra are the longest, those of the
third onlya little shorter; the shortest
are those of the seventh and eighth.
The atlas has no transverse pro-
cesses. Those of the second and third
vertebrae project directly outwards
and slightly downwards; those of
the fourth, fifth, and sixth upwards
and backwards. The seventh and
eighth project more directly outwards
and at the same time backwards ;
the ninth upwards and markedly
backwards. All the transverse pro-
cesses have cartilaginous epiphyses ;
the largest are those of the second,
third, fourth, and ninth vertebrae.

3. The spinous processes are
generally small, but individually of

varying size, appearance, and direc-

Fig. 4. °

i

13
Vertebrae of Rana esculenta, seen from

below, twice the natural size,

1 to 9 First to ninth vertebre.

e Urostyle.

o o Articular processes.

sc The two facets for articulation with the

urostyle.

tion, The longest are those of the third, fourth, and fifth vertebrae ;
these are; in transverse section, of a three-sided prismatic form, as

Cc

18 THE BONES AND JOINTS.

in the dorsal vertebrae of man; they are directed backwards and
provided with cartilaginous epiphyses. The spinous processes of the
sixth and seventh are shorter, compressed from side to side, project

Vertebral column of Rana esculenta, from
above, twice nat. size,

1 to g First to ninth vertebre.

e Urostyle.

oo Articular processes.

se Facets for articulation with the urostyle.

tt’ Transverse processes.

directly upwards, and are usually
without cartilaginous epiphyses ;
that of the eighth is still shorter: As
regards the spinous processes, those of
the third, fourth, and fifth vertebrae
resemble those of the dorsal vertebrae
in man; those of the sixth, seventh,
and eighth, lumbar vertebrae. The
ninth has either no spinous process or
only a rudimentary one. The first and
second vertebrae may be looked upon
as cervical vertebrae: the second has
a short, spinous process with a car-
tilaginous epiphysis. In the first, the
cartilage which unites the two halves

of the arch represents the rudiment -

of a spinous process.

II. Description or PARTICULAR
VERTEBRAE.

1. The atlas or first vertebra has
a thin body, compressed from above
downwards, and an arch. The body
has posteriorly a slightly raised, car-
tilaginous, articular head, which is
broader transversely ; in front it has
two oval articular facets, which are
separated from each other by a median
projection. Each facet is concave,
and directed forwards, outwards, and
slightly upwards. The arch is com-
pleted above by cartilage, which pro-
jectsslightly toform the rudiment ofa
spinous process. The hinder margin of
the arch bears two articular processes.
Transverse processes are wanting.

2. The second vertebra presents all the general characters of an

THE VERTEBRAL COLUMN. 19

ordinary vertebra, except that the transverse processes are directed
somewhat downwards.

3. The transverse processes of the third vertebra are longer than
those of the second : each is directed downwards, is broader at its
extremity than at its base, and bears a hammer-shaped cartilaginous
epiphysis larger than those of the remaining transverse processes.

4. The transverse processes of the fourth vertebra are the
longest: each is broader at its free end than at its base, is
directed upwards and backwards, and provided with a cartilaginous
epiphysis.

5, 6, 7. The transverse processes of the fifth, sixth, and seventh
vertebrae are smaller, contracted towards their free extremities, and
directed upwards.

8. The eighth vertebra is distinguished from the rest by its
body possessing no articular head. It presents, at each end, a con-
eave articular depression. The transverse processes resemble those
of the seventh.

9. The ninth vertebra unites the vertebral column with the hip-
bones, and is hence to be regarded as a sacrum. The body bears
on its anterior surface an articular head for articulation with the
eighth vertebra: on its posterior surface are two small rounded
and closely approximated processes (Figs. 4 and 5 sc) for articulation
with the urostyle. The transverse processes are strong, broader at
the free ends than at their origin, directed upwards and backwards,
and provided with cartilaginous epiphyses.

Ill. ARTIcuLATIONS OF THE VERTEBRAE.

The articular heads and depressions of the vertebral bodies,
together with the joint surfaces of the articular processes, are
covered with hyaline cartilage. The periosteum of the bodies, as
also that of the articular processes, forms true capsular joint liga-
ments. The articulations of the vertebrae are still further strength-
ened by longitudinal fibres, which extend along the anterior and
posterior surfaces of the vertebrae, and correspond to the ‘Tigamentum
vertebrale commune anticum et posticum of man. Between the
vertebral arches are membranes which represent the J/igamenta
intercruralia. Between the spinous processes are bands of connective
tissue which form ligamenta interspinalia. (For the articulation of
the atlas with the occiput, see page 24.)

C2

*20 THE BONES AND JOINTS.

IV. Srrvucture or tHE Vertresrar! (Figs. 6 and 7),

Each vertebral body consists of a cylinder of compact bone, which
is directly continued into the bony substance of the arch. In the
interior of the cylinder is found an isolated persistent vestige of the
chorda dorsalis (Ch): this is surrounded by cancellous bone (c), which
extends backwards towards the articular head and forwards directly
into the articular cartilage, compact bone being absent in these
parts. In a transverse section of a ver-
tebral body the following parts are seen
(Fig. 6):—a. An outer layer of compact
bone (0) (the transverse section of the
above-mentioned cylinder), which is formed
of parallel lamellae of varying thickness.
These, according to Gegenbaur, and as I
can confirm, are arranged in well-defined.
groups, each of five to eight lamellae.

Transverse section through aver- ‘The number of the secondary lamellae
tebra of Rana esculenta, magni-

Fig. 6.

fied. increases with the age of the animal.
3 SR a bone. b. In the interior, in the form of a cylin-
kh Chorda dorsalis. 2, 3
Ch’ Sheath of chorda dorsalis, der, is the remnant of the chorda dorsalis.
Compact bo: th f .
* “und lower surfaces of the Lt consists of a double sheath (C2/’) and
sia contents (Ch) composed of chorda-cells.

ce. Immediately around the persistent por-
tion of the chorda lies the central part of the
vertebral body, formed by transformation
of the vertebral cartilage and of the bases
of the original cartilaginous arches. At
each side of the chorda are large marrow-
spaces (c), filled with cells, from which
proceed narrower canals, winding in various

Longitudinal section through the directions, and anastomosing freely with
posterior half of the body of a

Partalion olf fiona seeulein: one another both before and behind. Their
oo ees TE ee walls are constituted partly of true bone
e Cancellous bone. : 5)
o Shell of compact bone. partly of cartilage.

1 Cf. Gegenbaur, (1) Uber Bau u. Entwicklung der Wirbelsiiule bei Amphibien
tiberhaupt u. beim Frosch insbesondere. Abhand. d. Naturforsch. Gesell. zu Halle,
vol. vi, 1861; (2) Untersuch. zur vergleich. Anat. d. Wirbelsiiule bei Amphibien
u. Rept., Leipzig, 1862. As regards the adult animal I can bear out Gegenbaur’s
observations. The scope and limits of this book forbid me to go further into the
developmental history.

THE SKULL. 21

V. Tue Urostyte (Figs. 8 and g).

The urostyle is a long, median, rod-like bone, which projects back-
wards, midway between the two hip-bones, and terminates over the
anus. The anterior end (Fig. 8 a) is the thicker and broader part
of the bone, and has two articular depressions (Fig. 9) for articula-
tion with the two facets of the ninth vertebra. The hinder end
is pointed and cylindrical, and terminates in a cartilage, which
is fixed in the tubular end of the
bone. The middle portion is almost
cylindrical, and has a groove along the y
ventral surface which gradually becomes Se
less marked behind. The dorsal surface ¢
bears a ridge (Figs. 8 and g s), which is "Tsuis of Rane
high and thick in front, becomes sharper from the side,}
and less prominent as it proceeds 2 yt tonder
backwards, and gradually disappears «+. Canal. verte-
towards the hinder third of the bone, — s Dorsal ridge
so that in transverse section the an- Ge: eet
terior two-thirds of the bone appear triangular,
with a ventral and two lateral surfaces: while the
hinder third is cylindrical. The anterior portion
of the bone contains a canal, canalis vertebralis
(Fig. 9 ¢.v.), which is a continuation of the verte-
bral canal, along which the hindermost spinal nerves
pass. On each side of the anterior portion of the
urostyle are small apertures (Fig. 8 ¢.c.), which lead
into canals (canales coccygei), which open into the
vertebral canal, and through which the coccygeal
nerves pass. In front of these openings and partly
overhanging them are small triangular projections rial
(Fig. 8) (processus transversarii): these, however, are side. win.
not constant, and are more often found in R. eseu- ¢ ae ox
lenta than in R. temporaria, in which latter species «.. Canal. coceyg.

the openings are smaller. , Pager

Fig. 9.

IL THE SKULL.

The flat form of the frog’s head, as in batrachians generally,
depends upon the wide separation of the jaw-bones of the two
sides, and on the large size of the orbital cavities and the horizontal

>

22 THE BONES AND JOINTS.

direction of their floors. The outer circumference of the head
forms a parabolic frame (Figs. 10 and 11), composed of the
maxillary (7), premaxillary (2), and quadratojugal bones (7). Im the
middle of this curved framework lies the elongated prismatic
cranium. Anteriorly, this is attached to the fore-part of the frame
by means of the cartilaginous skeleton of the organs of smell
(Fig. 11¢’); posteriorly, it widens out into two transverse arms (7),
which contain the organs of hearing. From this base, on either
side, a bony strut, composed of the posterior arms of the squamosal
(¢’) and of the pterygoid bones, passes backwards to the hinder end

Fig. ro. Fig. 11.

Skull of Rana esculenta, seen from below,

Skull of Rana esculenta, seen from above, twice natural size

twice natural size,

hi id. ¢ Cartilaginous wall of skull.
an age e Sphenethmoid. .—
Sp Piuihijroacical: . e Cartilaginous skeleton of nose, »-
.@ Premaxillary. » h’ Stylo-hyoid,
*j Quadrato-jugal. % ir i sey
4m Maxillary. in axillary.
«o Exoccipital, » - He Quadrate tract. «
op Opisthotic. ss Exoccipital.
«<p Prootic. » Pp Prootic, ; 9
4pt Pterygoid. p’ Anterior arm of prootic (ala magna autt.).
7 4 .
+ pl’ Posterior limb of pterygoid. p” ‘Trigeminal foramen.
tt Squamosal. — pl Palatine.
. pt Pterygoid.

* ’ Posterior arm of the same, DY. Postertor Hote G8 alery old.
— $ Parasphenoid,.;

~ wv Vomer. ~<

of the frame. 'The anterior arm of the squamosal bone (4) does
not quite reach the framework, but is attached to it by ligament
alone. Between the last-named arm posteriorly, the cranium on the
inner side, and the maxillary frame-work laterally, is a large space

representing the orbital and temporal fossae of human anatomy,

THE SKULL. 23

A. THe Cranium.

The cranium of the frog is a prismatic tube, wide behind, narrow
in front, and formed in great part of cartilage (Figs. 15 and 17). Our
indigenous species are characteristically distinguished from one
another by peculiarities in the form of the cranium. In 2. esculenta
it is long and narrow, in 2. temporaria short and wide. The superior
surface in the former is markedly concave, while in the latter it is
flat, and in 2. oxyrhinus arched. These differences are readily
recognised in the living animal.

The Bones of the Cranium.

1. The exoccipital bones, ossa occipitalic /ateralia, Cuvier
(Figs. 10, 11, 12, 14, 16 0).
Cuvier, l.c., p. 387781. XXIV, bb.—Dugeés, /. c., n. 14 Parker and Bet-
tany, ic., p. 166, exoccipitals.

These paired bones form the hinder part of the cranium; they
bound the foramen magnum, and articulate with the vertebral column.
They are imbedded in the cartila-
ginous matrix of the skull, and are
separated above by an unossified
part of this matrix (occipitale
superius, Dugés), which represents
the tabular portion of human
anatomy: below they are separated
by a similar part (occipitale Lasi-

H of Rana esculenta, seen fF6m
twice natural size.

a Stapes.
lare, Dugés) which represents the @, Columelia aur.
body of the occipital bone. They ¢ Condyles of exoceipitals
therefore properly represent only * Pocatan.
the condylar portions ( partes cou- 2 Sat OE sahcsad ballin
dyloideae) of the human occipital ¢ Squamosal.

bone. Each possesses a cartilaginous articular head, for articulation
with the first vertebra: these converge below, and suriound the
lower half of the circumference of the foramen magnum. This latter
has, in R. esculenta, a transversely oval outline; in 2. temporaria, a
somewhat heart-shaped outline, with the apex directed upwards :
in accordance with this the whole bone is wider than high in the
first species; and in the latter it is higher than it is wide. From
the upper and outer border of the foramen magnum on each side

24 THE BONES AND JOINTS.

a ridge runs obliquely outwards and downwards, in which lies
the suture between this bone and the prootic bones. This bony
ridge (processus mastoideus, autt.) is usually cartilagmous in 2, escu-
lenta, even in old animals; in &. temporaria, even in young: speci-
mens, it is bony. In the latter species the bones unite very early,
while in the former they remain separated by the primitive carti-
lage. Between this crest and the processus condyloideus there is a
depression (fossa condyloidea), with a hole ( foramen condyloideum)
through which the vagus nerve leaves the cranium. The exoccipital
take part in the formation of the labyrinth of the ear, as will be
noticed later on.

Articulation of the Exoccipital Bones with the Atlas. From the
middle of the anterior surface of the body of the atlas a ligament
arises, representing to a certain extent the lig. suspensorium dentis,
and attached to the basal portions of the exoccipital bones.

2. The prootic bones, ossa petrosa, Cuvier (Figs. 10, 11, and
12 p).
Cuvier, rocher, /.c., p. 388, Pl. XXIV, ee.—Dugés, n. 12, rupéo-ptéréal.

—Stannius, ala temporalis——Meckel, Schiidelstiick des Schli-
fenbeins,—Parker and Bettany, l.c., prootic.

eee bones lie at the sides and in front of the exoccipital
bones. As already explained, they remain in R. esculenta separated
from these by cartilage, while in 2. temporaria they early enter into
bony uni®n with them; this is due to the complete ossification. of
the processus mastoideus in the latter species, as stated above. The
prootics form the lateral expansions of the posterior part of the
skull in which the organs of hearing are placed. The large cavity
which contains the ear labyrinth is completed by the exoceipital :
internally it opens freely into the skull, and externally on the |
posterior wall of the skull through the foramen ovale, which is
formed by both these bones, The postero-lateral part of the prootic
usually remains cartilaginous: at the side and in front of the
Joramen ovale this cartilage is pierced by a small opening, through
which passes the wervus facialis or ramus tympanicus n. vagi (Volk-
mann). At the side there is a process to which the suspensorium
of the lower jaw is attached (Fig. 12 y): behind this is a hollow in
which the auditory ossicles lie, and which may be designated fossa
tympanica (Fig. 12 ¢). The anterior border of the bone forms the

THE

hinder and inner walls of the
orbit. Here also is the tr-
geminal foramen (Fig. 11 p”)
through which the J. ¢rigeminus

and the several nerves for

the muscles of the eye pass ;*

it represents the foramen ovale,
for. rotundum, and the fissura
orbitalis superior (sphenoidal
fissure) of the human sphenoid
bone. The foramen is some-
times, especially in young
animals, only a notch, which is
completed by cartilage. On
account of the relation of this
part (Fig. 11 py’) of the bone
to the nerves which pierce
it, the whole bone has been
named by Stannius the a/a
magna or temporalis of the
sphenoid; it has been also
looked upon as a bone which
contains these elements, as by
Dugés, who on this account
calls it rupéo-ptéréal.

SKULL.

25

Skull of Rana esculenta, seen from below, twice
natural size.

c

“
i<

ee

RVC ET ALIS
.

o° RRR

Cartilaginous wall of skull.
Sphenethmoid,
Cartilaginons nasal skeleton.
Stylo-hyoid.

Anterior arm of prootic.
Trigeminal foramen.
Palatine.

Anterior arm of plerygoid.
Posterior arm of pterygoid.
Parasphenoid.

Vomer.

Appendages of the Prootic Bones.

t. The styloid cartilage. From the cartilaginous portion of the
prootic the styloid cartilage runs downwards, backwards, and
inwards, and is continued directly into the anterior cornu of the
hyoid bone (Figs. 11 4’ and 12 4).

2. The auditory ossicles.

a. A thick cartilaginous dise, the operculum (Fig. 12 a),

closes the foramen ovale.

6. To the operculum is attached a bony, club-shaped piece,
the columella auris (Fig. 12 a’), which has at its inner, thicker

end a cartilaginous épiphysis, the interstapedial ;

it lies

transversely with the apex directed outwards, and this longer
portion is the mediostapedial.
e. To the apex of the mediostapedial is sttaichied® at an

26 THE BONES AND JOINTS.

obtuse angle, the third cartilaginous piece, the extra-
stapedial (Fig. 12 a”). It is attached to the tympanic
membrane, and by its upper portion is fastened to the
cartilaginous tympanic ring by a smaller piece, the supra-
stapedial.

3. The tympanic ring (aunulus tympanicus) is an annular cartila-
ginous frame ; or more exactly, has the shape of a short, truncated
cone, as it narrows towards the middle line: it is attached to the
squamosal bone. (See Organ of hearing.)

3. The parasphenoid, 0s sphenoidewm, Cuvier (Figs. 11 and 168).

Cuvier, l.c., p. 388, Pl. XXIV, d.—Dugés, n. 8.—Meckel, Theil des
Grundbeins.—Parker and Bettany, l.c., parasphenoid.

A large portion of the base of the cranium is taken up by this
cruciform bone. Of the two longitudinal median processes, the
posterior is by far the shorter, and lies in front of and partly |
below the cartilaginous os occipitale basilare. The anterior longer
longitudinal arm closes in the greater part of the cranium from
below, and articulates by its outer edges with that part of the
prootic bones often described as the alae magnae, and also with the
cartilage lying in front, which forms the greater part of the lateral
walls of the cranium. The anterior extremity of the bone articulates
with the palatine bones. The transverse arms lie on the under
surface of the exoccipitals and of the prootics.

The greater width of the cranium in 2. temporaria is associated
with the greater relative width of the anterior arm of this bone.

4. The fronto-parietal bones, ossa fronto-parietalia, Cuvier

(Figs. 10 and 14 fp).
Cuvier, /.c., p. 387, Pl. XXIV, c.c.—Dugés, n. 1. —Parker and are
l.c., fronto-parietal.

These are a pair of somewhat long, flat bones, which form the
principal part of the upper wall or roof of the cranium, and cover
in superiorly the cartilaginous cranium, which is here, in great
part, persistent. They are united in the middle line by the sagittal
suture; posteriorly they articulate with the exoccipital and prootic
bones ; anteriorly with the sphenethmoid, which they overlap like
tiles. The outer margin of each bone is bent somewhat down-
wards (Fig. 16 fp), and between it and the parasphenoid there is a
space in the wall of the cranium which is closed in by cartilage and
connective tissue only.

ee a.

THE SKULL. oF

These bones are narrower in R. esculenta, and along the sagittal
suture are depressed into a groove: where the superior surface bends
down to become lateral the edges are much more prominent. In
R. temporaria the bones are broader and flat or even somewhat arched.
The latter condition is still more marked in R. oxyrhinus.

5. The sphenethmoid, os ethmoideum (Figs. 10, 11, 14, and
6e).
‘ ) Cuvier, os en ceinture, /. ¢., p. 387, Pl. XXIV, a.—_Dugés, n.15.—__Rathke,
anterior or sphenoidal wing (Vortr. z. vergl. Anat. d. Wirbelthiere,
Leipzig, 1862, p. 42).Meckel, Riechbein, l.c., p. 502—Parker
and Bettany, /.c., ethmoid.
. The long tubular cranium is completed anteriorly by a single
bone, which forms at once the roof, floor, and lateral walls. It is
consequently more or less ring-shaped, on which account it has been
named ‘os en ceinture’ by Cuvier. Only the posterior portion is
annular, however : the anterior portion forms a double canal, with a
median partition, for the passage of the nerves of smell, and as these
canals are widened out anteriorly, this part of the bone helps to
complete the nasal cavities, which, however, are bounded for the
most part by cartilage, as described below. In some species of
frogs (as for example FR. occe/lata, Rathke) this cartilage is partly
ossified.
The sphenethmoid has on each side a small bony canal, running
forwards and inwards, through which the ramus nasalis of the first
division of the trigeminal nerve passes. |

The cartilaginous skeleton of the nose (Figs.14 and 162, 2”, 2”,
nz”). The anterior borders of the funnel-shaped cavities of the sphen-
ethmoid pass into cartilage, which forms two capsules, separated from
each other by a median cartilaginous septum, and opening laterally.
We can distinguish, (2) a cartilaginous septum, forming a continu-
ation of the bony one; (4) the floor of the nasal cavity, narrower
behind, wider in front ; (c) a roof somewhat narrower than the floor.
The floor and roof are united in front by an arched surface. From
this cartilaginous capsule various processes project, which unite it to
other portions of the facial skeleton : firstly, from the most posterior
portion of the capsule there passes transversely outwards a bar of
cartilage (sz), which, widenitg, becomes continuous with the carti-
lage (sp) forming the basis of the anterior arm of the pterygoid
bone. From the anterior angle a cartilaginous process passes out-
wards (Figs. 14, 16 2”), which is attached to a projection on the

28 THE BONES AND JOINTS.

anterior end of the maxillary bone; from the same spot a horn-
shaped cartilaginous process (w’, x”) curves round backwards and
towards the middle line. This projection bounds the nasal cavity
externally, sending off

a free process (7)

Fig. 14. on the way, and ends

with a double point on
the roof of the earti-
laginous nasal cavity
(n’”’). On the floor of
the nasal capsule, on
either side, is a knob-
shaped cartilaginous
eminence, running’
from behind, forwards
and outwards; this may
be regarded as an in-

bone. From the an-
terior wall there passes
into each nasal cavity
an almost horizontal,
partly ossified plate
(c.v.),ending posteriorly

Cartilaginous basis of the skull of Rana esculenta, from above,
twice natural size. Cartilage shown by stippling.

a.n,. Wings of nasal cartilage. p. Prootic.

c.n. Concha narium. pt Anteriorarm of pterygoid: jn a, free pointed bor-

e Sphenethmoid. pt’ Posterior arm of ptery-

Jf’ Foramina of cranium. goid. der. These are the

gn Nasal. s’ Cartilaginous cranium. =

fp ¥ronto-parietal. sp Cartilage of suspensorium. cornets of D ugés (2. Cs,

i Premaxillary. sp’ Cartilage under the squa- p, 12, Pl. 3 Figs. I,

Jj Quadrato-jugal. mosal, h 1

m Maxillary. sp” Cartilage under the ptery- 5), who correct oy ene =
este 3 id.

n,sn iiss os nasal skele 3 Fe act garded them as tur-
; ¢ arm 0 e . as

n’, a aot Sig FR 5 aetna binated bones. Cuvier

9 Exoccipital bones. described them as rudi-

mentary nasal bones!.
The alar cartilages of the nose bide still to be described. "They
are (a.v.) shell-shaped cartilages, hollowed out on the inner sides and

1 Cuvier (Ossem. fossil., V, 2. 388) says that these little bones are fixed outside
the nasal cavity, so that we may suppose that he confounded them with the
nasal cartilages found in this situation.. Duges correctly indicates their position
to be inside of the nasal capsule. Meckel (Vergl. Anat. II, 504) also regards
them as nasal bones. Bruch (Wiirzb. naturwiss. Zeitschrift, vol. II, 1861, p. 213)
could not find them in any frog-skull, doubtless because he did not look inside the nasal
capsules. :

dication of a turbinated

_ More anteriorly in the

space (f) which ex-

theosoccipitale superius.

THE SKULL. 29

decreasing in width from before backwards. They are movably
attached by their anterior broader ends to
the tips of the projecting portions of the
P bones, and are so arranged
as to bound the lateral margins of the
nasal apertures, which they overlap.

Fig. 15.

6. The cartilaginous basis of the
skull, Primordial cranium (Figs. 14, 16).
a. If the fronto-parietals be removed,
(Figs. 14, 16), a cartilage (s') is found
which partially closes the cranial cavity,
and which is usually perforated on either
side by a foramen (’).

median line is found a

tends to the spheneth-
moid bone, and is only
closed by connective
tissue: posteriorly the
cartilage extends be-
tween the exoccipitals
as far as the foramen

magnum, representing

b. The base of the
cranium is(Fig. 16)also
partly cartilaginous. If g
the parasphenoid (s) Certginom kal of Rana ele from be below, twice

be removed we find ¢ cCartitage of prootic.

pt Pterygoid.
above it a cartilage (s’) i ee: pt Articular surface for

which passes back- Premaxillary. r
wards between the ex- 5 ay e Parasphenoid.

Cartilage of suspensorium.
as far back as the nw roses of i attlegs WE ene
foramen magnum: it 4 Exoccipital. =p” carn ended lies

A :
corresponds to the os i nap airy Se

occipitale basilare.
e. The sides of the cranium are Seana almost entirely of car-

, fn ls “A aes”
Payee MN eg ee eer

30 THE BONES .AND JOINTS.

tilage. This cartilage fills the space bounded by the nasals above,
the parasphenoid below, the so-called a/a magna of the prootic bone
behind, and the sphenethmoid in front ; and has in its posterior part
an aperture (7) through which passes the xervus opticus, and below
this a smaller one (7’) for the zervus abducens. The extent of the
cartilage in the antero-posterior direction is greater in R. esculenta
than in 2. temporaria, or in other words the sphenethmoid stretches
further back in the latter than in the former.

B. Tue Bones or THE Facer.

The Suspensorium.

7. The squamosal
bones, ossa tympanica,
Cuvier (Figs. 10, 14 7).

Cuvier, oss. foss., V, 2.

390, Pl. XXIV, Figs. 1,

2n.—Dugés, temporo-

mastoidien, n. 10. —

Meckel, Articular part

of temporal. — Hall-

mann and others, quad-

rate-bone. — Parker
and Bettany, /.c., squa-
~ mosal.

The suspensorium,
which forms the arti-
SP’ py culation between the
cranium and the lower

Cartilaginous basis of the skull of Rana esculenta, from above,

twice natural size. Cartilage shown by stippling. jaw, 18 ye shaped, and
a.h, Wings of nasal cattilage. 0 Exoccipital bones. consists of cartilage
en, Concha narium. ~ p. Prootic.

. é@ Sphenethmoid. pt Anterior arm of pterygoid. covered by bone. Of
ff’ Foramina of cranium. pt’ Posteriorarm of pterygoid. the three arms of the
Jn Nasal. s’ Cartilaginous cranium. ‘
jp ¥ronto-parietal. sp Cartilage of suspensorium. T the anterior has a
i Premaxillary. sp’ Cartilage under the squa- : : .

F uiaadestoeel ae free pointed extremity
m Maxillary. sp” Cartilage under the ptery- (Fig. 14 i) at the
n,sn Cartilaginous nasal skele- goid. t lat, 1 =
n,n’ we Processes of the car. - pr ; l ee oe yt it 3
, ? ts
tilage, Posterior? “Aamosal. of the temporo-orbital

fossa: it- forms a true
processus zygomaticus, and is bound to the upper jaw by ligaments.
In &. temporaria it is comparatively much shorter than in PR.
esculenta. The posterior upper arm (/*) articulates with the prootic

THE SKULL. . BS

bone: the third or lower arm (/*), supported by a cartilage’, runs
backwards and downwards to unite with the side of the broad
hinder extremity of the quadrato-jugal bone.

The cartilaginous basis! of the suspensorium (Fig.17 sy, sp’) isa
direct continuation of the cartilaginous basis of the cranium, and
proceeds from it to the outer extremity of the prootic; from this
point the cartilage runs backwards and divides into two branches ;
of these, one (sp’) retains the original course backwards and
outwards towards the articulation of the lower jaw, and in con-
junction with the quadrato-jugal (7) forms this jot. The other
(sp”) is directed forwards along the anterior arm of the pterygoid
bone; it widens in front (sz), and becomes directly continuous with
the cartilaginous strut described above as projecting from the
hinder part of the cartilaginous olfactory capsule.

8. The quadrato-jugal bones, ossa juyalia, Cuvier (Figs. 10,

17, 19/)-
Dugés, tympano-malléal, n. 11.—Cuvier, l. c., p. 399, Pl. XXIV, Figs.
J, 2 0.—Hallmann, quadrato-jugal bone, /.¢., p. 39.—Parker and
Bettany, /. c., quadrato-jugal.

This is a small process of bone, likened by Dugés to a comma,
which rests by its posterior broader extremity on the cartilage of
the mandibular arch!, and forms with it a portion of the articular
head for the lower jaw. The anterior extremity is pointed, directed
forwards, and attached by ligament to the maxillary bone.

9. The pterygoid bones, ossa pterygoidea ( Figs. 10, 11,17, 19 pt).
Cuvier, l.c., p. 389, Pl. XXIV, Figs. 1, 2 m m.—Dugés, n. 9.—Parker
and Bettany, /. c., pterygoid bones.

These bones, shaped like the Greek letter 4, possess each three
arms : of these.the middle one is attached to the under surface of
the prootic bone by a cartilaginous process (Fig. 18 gv); the hinder
grooved arm lies upon the under surface of the cartilaginous suspen-
sorial arch (Fig. 18 sp’); andthe anterior arm (p¢) runs forwards
along the inner border of the anterior ramus of the suspensorium
(sp”), in contact with the maxillary, palatine, and nasal bones.

The cartilage just mentioned, by means of which the middle arm
of the pterygoid is connected with the cranium (compare Fig. 18),
proceeds from the cranial origin of the cartilaginous arch (sp),

turns downwards and then forms a sort of articular head (cpé),~

which is articulated to an oval flat elevation of the prootic cartilage

* This cartilage is the quadrate cartilage of Parker ; others regard it as the(upper
end of the cartilaginous mandibular arch, of which Meckel’s cartilage is the lower
distal part.

a

“

32

THE

Origin of the suspensory cartilage
(sp) from the skull, with attachment
of the pterygoid ; front view. Car-
tilage shown by stippling.

cpt Cartilaginous epiphyses of the

pterygoid bone, from the cartila-
ginous suspensorium.

Jj Quadrato-jugal bone.

pt Pterygoid bone. Xs

sp Origin of suspensorial cartilage

from the skull.

sp’ Hinder arm of same.

sp” Anterior arm of same,

Cartilaginous skull of Rana esculenta, from below, twice
natural size. Cartilage shown by stippling.
pt Pterygoid.

e Cartilage of prootic.

BONES

AND JOINTS,

by a movable joint. Externally the
articular head curves somewhat abruptly
into the bony substance (Fig. 18 pf)
of the pterygoid bone.

10. The maxillary bones, ossa
manillaria superiora, Cuvier (Figs. 10,
II, 17, 19 m).

Cuvier, /.¢., p. 389, Pl. XXTV, Figs. 1, 2kk.
—Dugés, n. 4, maxillo-jugal. — Parker
and Bettany, /.c., maxillary bones.

These are elongated, curved bones,
narrower behind, broader in front, and
forming with the quadrato-jugals the

bony support of the
~ face. The — superior

& surface is convex and
directed outwards, the
inferior surface is
grooved and _ bears
teeth along the outer
edge of this groove.
From the upper and
inner border of the
anterior half of this
bone a process (pro-
cessus. frontalis) passes
upwards, which articu-
lates ‘with the nasal
bone. The anterior ex-
tremity of the bone
articulates with the

f

sp

e Sphenethmoid. pt’ Articular surface for F
fp. Fronto-parietal. pierre, premaxillary bone, the
@ Premaxillary. r Optic foramen. ior with the quad-
Quadrato-jugal. 7» Foramen for N. abducens. posterio q
m Maxillary. s Parasphenoid. rato-jugal.
n,sn Cartilaginous nasal skele- s’ Cartilaginous cranium. <
ton. sp Cartilage of suspensorium. The maxillary bone
n’, n", n//7, wer’ Processes of sp’ Cartilage under squa- articulates at its an-
nasal cartilage. mosal, 5 ; ,
o = Exoccipital. sp” Cartilage under ptery- terior end (Fig. Ig 2 )
p Prootic. goid, a 4
pl Palatine. v _- Vomer. with a process of the

of the nose.

cartilaginous capsule

The broad plate of cartilage (Fig. 19 ~), under

a

4

“nasal cartilage is articulated

tin SKULL. 33

eover of the processus frontalis, connects the hindermost transverse
portion of the nasal cartilage with the cartilage which runs forwards
from the suspensorium upon the anterior arm of the pterygoid.

11. The nasal bones, ossa fronto-nasalia, Dugés (Figs. 10,17 72).
Cuvier, frontale anterius, l. c.,h.—Dugés, n. 2—Meckel, nasal bone.—
—Parker and Bettany, /. c., nasal bones.

These flat, triangular bones, which rest upon the nasal cartilages
(z), assist to bound the orbital cavities in front, and are connected
by their external angles with the maxillary bone on either side?.

12. The premaxillary bones, ossa intermaxi/laria (Figs. 10, 11,
17, 19 7).
Cuvier, /.c., p. 388, Pl. XXIV, Figs. 1, 2 f f—Dugés, n. 3.— Parker and
Bettany, /.c., premaxillary bones.

These two bones are united
in the middle line : each consists
of a tooth-supporting portion,
which completes the maxillary
areh, and an ascending pro-

cess, to the apex of which the

Fig. 20.

by a movable joint (az). As
muscles are attached to this
process, it becomes a_ lever,
by which movements are ef-

fected.

13. The palatine bones, 3 Skull of Rana oe proline below, twice

ossa palatina (Figs. 19, 20 p/). —Cartilaginous wall of skull.
e Sphenethmoid.
Cuvier, /.c., p. 389, Pl. XXIV, e¢ Cartilaginous nasal skeleton.

Figs. 1, 2 ii.— Dugés, n. 7.— ™ Stylo-hyoid.

# Premaxillary.
Parker and Bettany, l.c.,pala- , yfaxillary.
tine bones. Le Suamnan .

Are two transverse bony p_ Prootic.
- -* p’ Anterior arm of prootic.
bars, situated under the anterior }» Trigeminal foramen.

portion of the sphenethmoid ” Palatine
pt Anterior arm of pterygoid.

bone on either side: each ex- pt’ Posterior arm of pterygoid.
s Parasphenoid.

tends outwards from the-apex Veanie:
of the parasphenoid to the paneer bone, where this gives off its
ascending process to the nasal bone.
* For os nasale, Cuvier (I.c., g), cornet (concha), Duets, see cartilaginous nasal
capsule, p. 27.
D

34 THE BONES AND JOINTS.

14. The vomers, vomer (Figs. 19, 20 v).
Cuvier, /.c., p. 389, Pl. XXIV, Figs. 1, 2 11.—Dugés, n. 6.— Parker
e and Bettany, l.c., vomer.

A pair of flat bones, placed horizontally on the under surface of
the cartilaginous nasal capsule in the triangular space between the
palatine bone and the anterior portion of the arch of the jaw. They
limit the outer border of the floor of this capsule, which lies in
a groove on the dorsal surface of the bone. The outer border of
each bone has three processes, and between them two notches; the
hinder of these notches bounding the posterior nares. The inner
borders of the two bones touch, and the under surface of each bears
a transverse row of small, pointed teeth.

) 15. The mandible, mawilla inferior (Fig. 21).
Cuvier, /.c., p. 398, Pl. XXIV, Figs. 1, 2 rs¢.—Duges, n. 16, 17, 18, 19.—
Parker and Bettany, /.c., mandibular arch.

The mandible consists of two bony arches united by ligament i in
the middle line, and each formed of four pieces. These are, (1) the
: i angulosplenial, a

strong, bony piece
(Fig. 21 C, B1, A1),
which forms the in-
ferior and internal
part of the lower
jaw; below, it ex-
tends posteriorly, as
far as the articula-
tion ; in front, it is
attached to the den-
tary. In the greater
part of its length it
has a groovedirected
upwards and out-
wards (C, 4), and
above has a_ pro-
cess which repre-

F'g. 21.

A Mandible of Rana esculenta, from above, nat. size.

B External view of lett side, } twice nat, size, sents the processus
C Angulosplenial, a .
t. Angulosplenial. coronoideus : (2) the
2. Dentary.
3. Mentemeckelian, dentary (4 25 B
4,4 Meckel’s cartilage, 2), a bony lamella

a. Rudimentary processus coronoideus. :
b. Groove for Meckel’s cartilage. which rests on the

—— =" | 4

THE SKULL. 35

outer surface of the anterior half of the angulosplenial, and articu-
lates in front with Meckel’s cartilage; it is a thin, flat lamella of
bone ; (3) in the groove of the angulosplenial is found a‘cartilage
occupying its entire length (4 4, B 4), Meckel’s cartilage; it is
broader behind, and here forms the articular fossa of the lower jaw ;
anteriorly it is covered by the dentary, and articulates with the
(4) mentomeckelian (4 3, B 3) at its anterior end, which is bound to
its fellow of the opposite side by ligaments, and unites the two
halves of the lower jaw.

The upper part of Meckel’s cartilage, which forms the joint with
the suspensorium, must be regarded as the articu/are; to this also
belongs the anterior, ossified portion of the seacipimecksliin 1; the
dentary, which covers Meckel’s cartilage, must represent the os
dentale* ; the first and largest bone, the angulosplenial, which lies
on the inner side of the cartilage, must be considered as the os oper-
culo-angulare, Duges, for it contains the elements of these bones.

16. The hyoid bone, os hyoideum (Fig. 22).
Parker and Bettany, /.c., hyoid.

This consists of a broad, thin, cartilaginous plate, with processes
passing from it as represented in the figure. We distinguish in it :—
(a) the body (#), somewhat oblong, and
wider in front than behind. From the
anterior angles there projects on either side
a blunt rounded process (4); from either
posterior angle a more pointed process (4).
(b) The anterior cornua (H’) (cornua sty-
loidea) project from the anterior border of
the body, first in a forward direction, then
ina curve backwards and upwards (compare
Fig. 12). to unite with the cartilage of the
prootic bone. Where the direction of these Hyoid of Rana esculenta,
cornua is changed each sends off a short _,, Se peat,
blunt process. (¢) The posterior cornua = #" Anterior horn. *

(cornua thyroidea) (H”’) are bony rods which °™*"0r hom.
run from the hinder margin of the body, diverge posteriorly, and
enclose the beryex-

? Dugts, os feud ? Duges, surangulaire.

36 THE BONES AND JOINTS,

+ / II. THE STERNUM (Fig. 24 es, hs).

Cuvier, /.c., p. 401, Pl. XXIV, Fig. 31 e f—Dugés, n. 27, 28.—Parker
and Bettany, /.c., sternum.

The bones of the sternum are in very close relationship with the
shoulder-girdle, and some difference of opinion exists as to the rela-
tions of the several parts.

Fig. 23. The following parts must be regarded as undoubtedly
es belonging to the sternum :—

1. An anterior part, consisting of a bony and a carti-
laginous portion.

a. The omosternum (Figs. 23, 24 ¢.8.) is a bony
rod, wider behind, narrower in front, and supports
4. The episternum (Fig. 24 es’), a semicireular

anon plate of calcified cartilage, with a thin free border
of Rana eseu- ; :
lenta, twice of unchanged hyaline cartilage.
nat. size. : : ney
Shier. 2. A posterior part, which also consists of a bony
p Posterior and a cartilaginous portion.

extremity.

Fig. 24. @ ,

Shoulder-girdle and sternum of Rana esculenta, twice nat. size. Sade aa
The scapula and suprascapula are turned outwards,
c. Connecting cartilage. hs, Sterhum proper
el, Clavicles and precoracoids, hs’ Xiphisternnm,
co Coracoid. + o Bone.
» es, Omosternum. o Caleified cartilage.
\ es’ Episternum. se. Scapula.

h Hyaline cartilage. se’ Supraseapnla.

- >

Oe en. el ea a men

THE PECTORAL GIRDLE. 37

a. The sternum proper (Fig. 24/.s.), a rod of cartilage
ensheathed in bone, broader in front and narrower behind.
To its posterior extremity is attached

4. The cartilaginous xiphisternum (Fig. 24 /s’), a plate, the
shape of which is best understood by referring to Fig. 24, and

the structure of which is similar to that of the episternum.
3. The epicoracoids* lie between the episternum and the sternum
proper: they are a pair of narrow cartilages, closely applied to
each other and placed between the ventral ends of the precoracoids

and coracoids, see p. 40.

IV. THE BONES OF THE ANTERIOR EXTREMITY.

A. Bones or THE SHOULDER-GIRDLE.

The shoulder-girdle of the frog (Fig. 25) consists of four bones,
two in the upper or scapular portion, and two in the lower or

coracoid portion.

1. The scapular portion.
a. The suprascapula, pars supra-
scapularis scapulae, scapula superior
8. omolita (Figs. 258, 26, 27).
This forms the upper, thinner por-
tion. It is trapezoid in shape, its
narrowest, thickest, and lowest
border articulating with the sca-
pula. The remaining three borders
are free; the posterior and supe-
rior borders are very considerably
thinned out, the inferior surface
is curved towards the ventral
surface.” Only the thin upper and
hinder borders (4/4) are of hyaline

_ cartilage; the middle portion (co)

consists of calcified cartilage; the

Sexuerane :

Fig. 25.

section, diagrammatic.

Articulation of these two.
Vertebra.

lateral part (0) and the anterior border (0’) of true bone.
The bony part forms a thin plate striated both radially and

* Duges, l.c., p. 61, regards the cartilaginous laminae as os episternale and proc.
ziphoideus, and the two bones ¢.s. and h.s. (Fig. 24) as sternum.

38 THE BONES AND JOINTS.

concentrically with the margin. The anterior border (o’) is bent
on itself so as to form a groove (Fig. 27)... The dorsal surface
of this bony plate is quite smooth, and covered only by periosteum ;
the ventral surface, on the contrary, is for the most part covered

Fig. 26.

Suprascapula of Rana esculenta, from above,
twice nat, size.

Fig. 27.

Suprascapula of Rana esculenta, from below,
twice nat. size.

co Calcified cartilage.
kh Hyaline cartilage.

co Calcified cartilage.
co’ Layer of calcified cartilage on the under surface

o Bony portion. of the bone.
o Anterior curved border. hk Hyaline cartilage.
0 Bony portion,

o’ Anterior curved border.

by an even layer of calcified cartilage (Fig. 27 co’). This passes
directly into the second portion of calcified cartilage (co); so that if
the whole be dried, the thin hard lamina of bone can easily be split
away from the underlying parchment-like cartilage. The layer of
calcified cartilage is, however, not so complete that the suprascapula
can be said to consist of calcified cartilage.

b. The scapula (Figs. 25s, 28, 29) is a long, flat, four-cornered
plate of compact bone, contracted in the middle, and wider at either
end. From above (Fig. 28 /) it descends to the shoulder-joint with a
slight curvature, with the con-
-vexity directed outwards. The
inferior or ventral border (Fig.
28 m), which assists in the forma-
tion of the shoulder-joint, is cleft
into two processes, a ventral and
a dorsal. This may be best seen
by looking at the border of the
bone from behind or before (as
in Fig. 29). The lower ventral
process (Fig. 29 v) may be re-
garded as the acromion, or at

Fig. 28. Fig. 29.

Left scapula of Rana esculenta,

from below, twice nat, size. Scapula seen

from behind,

a Anterior border. . 2
twice nat, size,

c.a. Cavitas articularis.
! Outer border, ¢.a, Cav. articularis.
m Inner border. d__ Dorsal process,
p Posterior border. vw Ventral process,

THE PECTORAL GIRDLE. 39

- least as a rudiment of the acromion, 7. ¢., spina scapulae. The upper
dorsal process evidently represents a rudimentary processus coracot-
deus. The anterior border (Fig. 28 a) is free, somewhat sharp, and
slightly concave; the posterior (Fig. 28 p), also concave, is free
externally ; while internally, where the division of the ventral border
commences, it takes part in the formation of the articular cavity of
the shoulder (Figs. 28 and 29 c.a.).

Articulation with the suprascapula, The scapula consists of
a shell of compact bony tissue and an inner portion of cancellous
tissue ; this latter passes, at the boundary between this bone and the
suprascapula, through an intermediate layer of calcified cartilage,
which is directly continuous with the cartilage of the suprascapula.
The compact superficial layer ceases where the calcified cartilage
begins, and the periosteum of the scapula passes directly into the
perichondrium) of the suprascapula.

2. The ventral portion of the shoulder-girdle consists of three
parts, which lie one behind the other.

a. The larger and posterior bone, the coracoid (Figs. 24 co, 30),
is contracted in the middle, and expanded
at either end, especially at the sternal end.
The inner half is flattened from above down-
wards; externally it becomes more cylindrical.
The anterior and posterior borders are markedly
concave; the outer border (Fig. 30 /) ar-
ticulates by means of a cartilage with the
proc. coracoideus of the scapula ; the inner bor-
der (m) is separated from its fellow of the
opposite side by the epicoracoids. This immer | sa twice nat
border is so broad, that it almost touches the size. ;
inner end of the clavicle (Fig. 24 ¢/.). A @ From below.
coracoid foramen is thus formed between the 1: outer extremity.
two bones, similar to the foramen ovale of the ™ ee
pelvis.

b. The small anterior bones of the ventral portion of the shoulder-

girdle (Figs. 24 e/., 31), I, like Cuvier and Fig. 31.
others, regard as clavicles. Dugés (n. 33)

names them ‘acromial. Each bone is nar- fe: ae
rower than the coracoid, smaller internally a att a. aie
(m), broader externally (/), and articulates by twice mat. size.”

1 Outer extremity.

this broader end with the cartilage uniting the — m Inner extremity.

40 THE BONES

Right shoulder-girdle of Rana esculenta, from

above.
ca Cay. articularis. co Coracoid.
ce Cartilage. sc Scapula,
cl Clavicle. sc’ Suprascapula.

AND JOINTS.

dorsal and ventral portions ;
the inner extremity rests upon
the epicoracoid. The clavicle is
grooved on its superior and
posterior surfaces in almost its
whole length; the groove widens
externally (/), and contains

e. The precoracoid (Fig.
34c/), a slender bar of cartilage,
connecting the anterior edge of
the scapula with the sternum.

Cartilages of the shoulder-girdle (Figs. 24, 32, 34). A car-
tilage (c), described by Dugés as the ‘paraglénal,’ connects the
scapula with the coracoid, and converts the notch between the two
processes (s and v) on the inner border of the scapula into an
aperture opening posteriorly into the glenoid cavity, and which is

filled up by the lining cartilage.

This cartilage connects the two

processes with the coracoid; being thicker between this and the
proc. coracoideus, it takes an important share in the formation of

Fig. 33

Hinder border of the sca-
pula and coracoid, with
the connecting cartilage

Caner ‘ethics of a young specimen of Rana esculenta,

enlarged to the adult size.

¢ Connecting cartilage.
e Epicoracoids.
c’ Ligament between the two cartilages.

and shoulder-joint, twice cl. Clavicle.
nat, size. cl’ Clavicle and precoracoid.
ec Connecting cartilage, .co Coracoid.
d_ Dorsal process. é co’ Cartilage of same,
ca Coracoid, es Omosternum.,
sc Scapula. hs Sternum proper.

v Ventral process.

the floor of the glenoid cavity. At the outer extremity of the
clavicle the cartilage projects and is then continued in the groove

7
J
j

THE FORE-LIMB. 41

on this bone towards the middle line (Figs. 32, 34), where it
widens out, and is united by its external margin with the sternum,
thus forming the precoracoid as already described, see p. 40.
These connections are best seen in young animals, as is shown in
Fig. 34.

The clavicle (c/) is of ossifying cartilage; the cartilage (c), the
epicoracoid, is very large, and hyaline, and at ¢/ runs directly into
the epicoracoids, which are here united mesially by ligament. In
the fully developed animal the whole of the epicoracoid changes to
calcified cartilage, as also does the precoracoid lying in the groove
of the clavicle.

B. Bones or THE Fore Limp. *

1. The arm has but one bone.
The humerus, 03 humeri (Figs. 35, 36, 37). The shaft of the
humerus is, on the whole, cylindrical, the middle part being the

Fig. 35. Fig. 36. Fig. 37.

)).

Humerus of Rana es- Humerus of Rana es- Humerus of Rana
culenta, female, seen culenta, male, seen esculenta, female,
from below. from below. outer side.

Figures twice natural size.
e Anterior extremity. ¢ Posterior extremity. ed Crista deltoidea.
em Crista medialis. # trochlea.

narrowest ; its dorsal surface is slightly concave, the ventral surface
convex. In the upper half the cylindrical form is indistinct, from
the presence of a well-marked crest (crista de/toidea) upon the under
or ventral surface. The hinder half of the bone has very different

42 THE BONES AND JOINTS.

shapes in the two sexes : in the female it remains cylindrical as far
as the elbow-joint; in the male, on the posterior surface, where
the erista deltoidea ceases, a marked ridge (crista medialis) arises,
which gradually winds inwards and terminates at the inner condyle.
This sexual difference is found in all the three species described in
the Introduction, and it would seem that this ridge increases in height
during the pairing season. The muscle which arises from this process
is the flewor carpi radialis (Fig. 74 Fe), and it attains, in the males, a
very large size at the same period; indeed, it is at its origin twice
as broad as in the female. Dugés! has incorrectly stated that
this crista is a peculiarity of Rana temporaria, and is wanting in
Rana esculenta. Pouchet? first observed that it was a sexual dis-
tinction.

The anterior articular extremity presents a rounded head, which is
somewhat flattened externally. The inferior ventral border is sharp,
and developed into the above-mentioned bony crest (erista deltoidea) ;
the free border is arched and curved outwards. Above, on the
outer surface of the head, is found an eminence which may be
a rudimentary ¢uberc. maius. The inner half of the head is
articular.

The posterior articular extremity consists of a rounded head (c’),
attached to the posterior extremity of the shaft; internal to this is
a small ¢roch/ea (+), placed upon the inner condyle. The external
condyle is but small. The head is embraced by these condyles.
Upon the under surface, above the head, is the fossa cubitalis
anterior. The structure of the two articular extremities of the hu-
merus differs ; the upper, as in long bones generally (see page 16),
consists of hyaline cartilage surrounded by calcified cartilage, which
again is covered by hyaline articular cartilage; the lower extremity
is composed of spongy bone, with roundish marrow spaces, and for
the most part covered by a layer of calcified cartilage.

The shoulder-joint. The socket is formed by the (posters border
of the scapula, by both the processes of that bone, the outer portion
of the coracoid, and besides these by cartilage, which forms the
articular surface already described (Fig. 33). In the macerated
bone the floor of the socket opens dorsally into a fossa
between the processes of the scapula (Fig. 32). This opening, in
the natural condition, is closed by synovial membrane only; the
cartilage covering the rest of the space being absent (the sac may

1 Le, p. 68. * Compt. rend. vol. XXV, 1847, p. 761.

THE FORE-LIMB. 43°

easily be inflated, either from the joint itself or through the opening).
The margin of the socket consists of a /aérum, partly fibrous and
partly cartilaginous, which is easily removed entire. The capsule,
which is attached beneath the caput humeri, arises from this. From
the articular cartilage of the ventral margin of the socket, and from
the adjacent part of the scapula, proceeds a strong band, which is
inserted into the flattened outer surface of the head.
2. The forearm.

The radio-ulnar, 0s antibrachii (Fig. 38). The two bony
elements of the forearm are fused into one, which, however, shows
traces of its compound character. Of these two bones, Fig. 38.
that which forms the inferior (in man anterior) border ee
is the radius, the other the ulna. The relative posi- /]
tions of the bony elements are such that they ap-
pear to be in a state of semi-pronation ; by this the
thumb-border of the arm is directed downwards (in
man forwards). The two bones so united form a
flattened, tube-like bone, the grooved surfaces of
which are directed inwards and outwards respectively ;
the borders being dorsal and ventral. The shaft of
the bone is narrower above, becoming gradually wider
below. In the upper half, the groove showing the Radio-uinar of
line of junction of the two bony elements is ‘° Msht side

of Rana escu-

scarcely visible, and it appears as though this part —nta,twicenat.
consisted of ulna alone, the radius not reaching so | paaime
far; below the groove is more marked. The upper ~ Coe
articular extremity appears to consist of an olecranon u Uina.
(Fig. 38 wu’) and a processus coronoideus (r’), between “ ”erne™-
which is the greater sigmoid cavity (cavitas sigmoidea major) for
the processus cubitalis humert. A more careful examination shows
this to be incorrect : the portion of the concave articular surface,
_ which lies in the immediate neighbourhood of the ventral border,
undoubtedly represents the articular surface of the capitulum radii,
and the upper portion of the articular surface (at u’) belongs to the
ulna and articulates with the ¢rochlea- (Figs. 35, 36 ¢) of the
humerus. The inner. border of the upper extremity of the bone
articulates with the groove ¢ of the humerus. The inferior
extremity forms one of the usual cartilaginous epiphyses, enclosing
the two bones. That part of the extremity corresponding with
the radius is triangular and convex, it is prolonged upon the
inner or under surface of the bone by means of a process; the

r

|

\ L
4

» 44 THE BONES AND JOIN''S.

ulnar portion of the bone forms a capitulum. The structure of
the inferior extremity is that of epiphyses in general, except that
there are two medullary cavities in a common sheath of calcified
cartilage; the anterior head consists of cancellous tissue, with a
covering of calcified cartilage.

Fig. 39. 3. Bones of the hand (Fig. 39).
Dugés, Pl. VIII, Figs. 37, 38, 39, 40, 41,
42, 43, 52,

a. Bones of the wrist, ossa carpi.
These are arranged in two rows, proxi-
mal and distal. The proximal or an-
terior row has three bones, viz. :—

1. Os lunatum, the middle bone (Fig.
39 2), Dugés, n. 38, articulates with the
radial part of the articular surface of
the radio-ulnar by a concave surface ;
with the large bone of the second row
(Ac) it articulates by means of a rounded
head; and with the two other bones
of this row, os naviculare (n) and pyra-
midale ( p), with the former by a saddle-
shaped surface, with the latter chiefly
by ligament. The bone is irregularly
cuboid ; the dorsal and palmar surfaces
are non-articular. With Dugés I regard
this bone as os lunatum; Mertens? re-
gards it as os naviculare.

2. Os pyramidale (Fig. 39 p), Duges,
Bones of the forearm and hand of Rana . an
esculenta, right side, dorsum, twice TN. 375 articulates with the ulnar part

pear of the posterior articular extremity of
a ; zal 3

he Os capitato-hamatum. the radio-ulnar. Anteriorly the bone
Z Os Ilunatum. . . .
ss Cea airtastat has a facet which receives the capitu-
On teees Jum ulnae, and alongside this a small

p Os pyramidale. a : 7
r Radial portion of the radio-ulmar. — flat’ surface which articulates with the

¢ Os multangulum majus ortrapezium. 4. Z .
t’ Os multangulum minus or trapezoides. radius. Posterior ly > opposite to the

« Ulnar portion of the radio-ulnar, y z ; is
Perea whats Glee fetes second row, it presents a long raised
of os metacarpi, the second and third articular surface, extending from the

f two, fourth and fifth of three
vhalanaeeme ov ie dorsum to the palmar surface; and on

1 Mertens, /.c.

a

RG Eee es ae eee

THE FORE-LIMB. 450

the palmar aspect of the bone is a ridge running from before back-
wards. Mertens names this bone os /unatum.

3. Os navieulare (Fig. 39 2), Dugés, n. 39. The third bone
of the first row does not articulate with the bones of the forearm.
It is connected with the os /unatum. by a saddle-shaped surface, pos-
teriorly with the os capitatum by means of a concave surface. On
the inner surface is a small concave articular facet for the os mu/t-
angulum minus or trapezoides (Fig. 39 ¢#). The convex palmar
surface of the bone articulates with the os mu/tangulum majus (t) ; the
radial side is non-articular, and with the os /unatum forms a ridge
directed forwards. Mertens names this bone os friguetrum. It is
evident, however, that if the arrangement in man obtains as a
standard, the nomenclature of Dugés, which I have here used, is
correct; but the os nariculare is no longer in contact with the
articular surface of the os antibrachit.

The second or distal row also consists of three bones :—

4. Os capitato-hamatum (Fig. 39 he), Dugés, n. 40, 41, 42,
corresponds with the os capitatum and jamatum1, which are here
fused together. It is the largest bone, and articulates with all three
bones of the first row; it is crescentic, with the concavity directed
posteriorly, and on the convex surface has three facets for the three

outer ossa metacarpi.
5. O08 multangulum minus, s. trapezoides (Fig. 39 t’), Duges,

- 1. 43, is a small bone lying next to the foregoing; it articulates

with the os metacarpi Il, and anteriorly with the os xaviculare.
Dugés considers it to be the os trapezium.

6. Os multangulum- majus, s. trapezium (Fig. 39 ‘), is a small
bone, which is placed on the convex palmar auricular side of the
os naviculare. Dugés regards this bone as 0s metacarpi pollicis
(Dugés, n. 44), Mertens as multangulum minus. It appears to me
that the interpretation here given is justified, because it articulates
with the rudiment of the thumb, and as it possesses no resemblance
to a long bone it cannot be regarded as an os metacarpi.

Structure of the carpal bones. All the carpal bones consist
of calcified cartilage, though variations due to age occur in the
amount of the deposit.

Wrist joint. As stated above, the os /unatum and os pyramidale are
articulated with the forearm. In addition to the capsules uniting
the parts, there are strengthening ligaments, two of which require
special mention. One of these arises from the palmar surface o

* Dugés thinks that os trapezoides is also included. :

» 46 THE BONES AND JOINTS.

the posterior extremity of the ulna, and passes to the sharp palmar
ridge of the os pyramidale, where it is attached, and is inserted into
the os capitato-hamatum ; the second ligament passes in a similar
manner on the palmar surface from the radius to the os naviculare.
Between the two ligaments there is on the volar surface a deep

excavation.

Fig. 40.

Bones of the forearm and hand of Rana
esculenta, right side, dorsum, twice nat,
size.

a Radio-ulnar.

he Os capitato-hamatum.

2 Os lunatum.

m Ossa metacarpi.

n Os naviculare,

p Os pyramidale.

vr Radial portion of the radio-ulnar,

¢ Osmultangulum maius or trapezium,

¢ Osmultangulum minusor trapezoides,

« Ulnar portion of the radio-ulnar,

J -V First to fifth fingers, the first only
of a metacarpal, the second and third
of two, fourth and fifth of three
phalanges.

Movements of the hand. The two
bones of the forearm being firmly
united, pronation and supination, as
in man, are impossible. The normal

position, as already remarked (see radio-

ulnar), is that of semi-pronation (com-
pare Figs. 2 and 74). If the animal
be in its natural posture, with the arm
bent at the elbow (Fig. 1), it can touch
the ground with the ulnar border only ;
but when the whole surface of the hand
rests upon the ground, the action is
brought about as follows: the plane of
the carpus is in extension parallel with
that of the forearm ; in flexion, almost
at right-angles with that plane (Fig.
74). The os dunatum glides on the pro-
longation of the articular surface on.the
inner palmar surface of the radius,
while the os pyramida/e is held firmly
by the ligament just described. The
hand follows the movement of the os
/unatum, and at the same time the three
outer ossa metacaryi gliding with it in-
wards, the fingers of the hand turn
inwards.

b. The Bones of the metacarpus, ossa
metacarpi (Fig. 40m). Of these there
are five: the second to the fifth are of
about equal length; the first, forming
the rudiment of the thumb, hidden
beneath the skin, is much shorter.
This metacarpal bone of the thumb is
regarded by Dugés and others as the

first phalanx. My reason for describing it as a metacarpal has

THE PELVIC GIRDLE. 47 »

already been given. This bone also presents differences in the two
sexes. Meckel’s’ observation that it exists only in the male is
incorrect ; it is a large, broad and sickle-shaped mass of calcified
cartilage 6r even true bone, while in the female it is simply a small
cartilaginous rod ; as this almost entirely disappears in dried speci-
mens, Meckel’s statement is explained. The second finger has in
the frog assumed the functions of the thumb, and, in the males, in
the breeding season swells and undergoes an essential alteration of
structure. The metacarpal of this finger also displays differences
in the sexes, being in the male stronger, broader, and on the inner
side provided with a spine-like prolongation, for the tendon of the
abductor digiti II (pollicis) longus, which attains an unusual de-
velopment during the breeding season. The remaining metacarpal
bones, the third, fourth, and fifth, are of similar form, the last
being provided with a tubercle. The anterior articular extremities
are rather broad and concave, and the posterior have rounded
heads.

ec. The phalanges, phalanges digitorum. The hand has four fingers
and the rudiment of a fifth, which latter is completely hidden under
the skin, and as already explained, consists of a metacarpal only.
Of the four fingers, the fourth is the longest, the third the shortest,
the second and fifth of intermediate and about equal length; the
fourth and fifth fingers have each three phalanges, the second and
third have each two. Their shape is not unlike that of the human

phalanges.

V. THE BONES OF THE HINDER EXTREMITY.

A. Bonzs or tue Petvic Girvie (Fig. 41).

The pelvis has a characteristic V-shape, the pubic and ischiatie
bones of the two sides together forming a vertical plate (ap),
which divides anteriorly into the two iliac bones (i). The pubic
and ischiatic bones being united by their median surfaces, one can

only speak of the pelvic cavity as the space between the two
‘ia

1. The ilia, ossa i/ii (Fig. 42 il). In these a broader part or

' Le., II, 464.

48 THE BONES AND JOINTS.

body can be distinguished, which takes part in the formation of the
acetabulum (a). The hinder and broadest part of the bone is joined
to the corresponding portion of its fellow by ligament ; anteriorly the
two diverge, bounding a cone-shaped cavity, the pelvis. The suture,
by which the body of the iliac bone is united with the ischiatic
and pubic bones, runs from above downwards through the middle of
the acetabulum (Fig. 42,

from yp through the ace-
‘abulum to is). Inferiorly
and in front the united
iia form a prominence
(s), which represents the
symphysis oss. pub. of
man. The expanded por-
tions of the ilium rest
directly over the articu-
lar cavity by means of
a somewhat constricted
Pelvis of Rana esculenta, part or root, The ala is
from below, nat. size. g, sabre-like bone f with ©
Portes the sharper, more convex

p Pubic bone, border directed upwards ;
the more concave, thicker

border downwards. The two surfaces,
of which the imner is grooved, are
directed respectively inwards and outwards.
' The broader part of the blade springs
directly from the neck or root (at 27’), and
at this end of the sharp convex border
is a process, process. sup., from which

Fig. 42. Fig. 41.

Pelvis of Rana esculenta, left side,

twice nat. size. the tendon of the m. vastus externus arises.
a Acetabulum. : .
Hierdtiney border. The anterior end of the blade is a hol-
ee Mea low cylinder, containing cartilage, mov-
al’ Superior process. ae A
vis Ischium. ably articulated to the transverse process
is’ Tuber ischii.
p_ Os pubis, of the last vertebra or sacrum.
DR cassie esheets gator 2. The ischia, ossa ischii (is), are irre-

zw Lower border of same,
. gular, four-cornered plates of bone, united

together by the whole extent of their inner surfaces. The vertical
plate formed by the union of the two bones takes only a very
small share in the formation of the articular cavity. Above, it has
a somewhat sharp border, continued with the ilium into a process

THE HIND-LIMB.

(és’) corresponding with the united ¢udera ischii ;
the hinder border, which is united below with the
pubic cartilage, is curved. }

8. The pubes, os pubis (Figs. 41, 42, 43 p)-
Ossified pubie bones do not exist; even in old
animals they are composed of calcified cartilage.
Each is a triangular cartilage, wedged between
the ilium and ischium, but also taking part
in the formation of the acetabulum. The pubes
of opposite sides are, as shown in section in
Fig. 43, united by ligaments in the median
plane.

B. Bones or THE Htxp-Lioe.
1. The thigh.

Horizontal _ section
through the iliac,
pubic, and ischiatic
bo

opposite sides.

The femur, os femoris (Fig. 44). The shaft is cylindrical,

with a slight double or S-shaped curve. In the
anterior portion the convexity is directed upwards,
in the two hinder thirds downwards. Towards
the hinder extremity it is flattened from above
downwards: The anterior extremity is a rounded
articular head placed directly on the shaft like
that.of the Aumerus. This head is somewhat flat-

~ tened from side to side; and in structure resembles

that of the humerus. The inferior extremity is
rounded below, but flattened above (towards the
hollow of the knee) and behind.

Hip-joint. The articular cavity is deepened by
a fibrous ring, Jabrum cartilagineum, which fits
closely upon the caput femoris ; from this /abrum the
joint-capsule arises, to bé° inserted behind the head ;
close to the lower border of the cavity a Jiga-
mentum teres arises, which is inserted into the caput

femoris.

2. The leg.
Tibio - fibula, os cruris (Fig. 45). This
consists of a single bone, the os cruris; it is

often called the ¢isia, but presents, however, dis-'

tinct indications of being formed of two bones,

the tia and fibula. The shaft is not. quite

straight ; it is thinner in the middle and flattened
E

Fig. 44.

Femur of Rana escu-
ienta, right side, twice
nat. size.

a Anterior extremity.

p Posterior extremity.

50 THE BONES AND JOINTS,

from above downwards. On the upper as also
on the lower surface of the bone is a groove,
passing from the middle towards each ex-
tremity ; this deepens as it proceeds, and is an
indication of the compound nature of the bone.
@ In the middle of each surface of the bone
is the opening of a canal, through which a
bristle may be passed: the canal has bony
walls, The medullary cavity is, for the most
part, double, being single only in the middle.
The anterior extremity is articular, and presents
a median groove, which is prolonged on to the
under surface. The posterior extremity forms -
a transverse condyle, which has at its imner
part a notch for the tendon of the m. tibialis
posticus.
The knee-joint consists of a capsule strength-
ened by theinsertions of numerous tendons.
Within this the articular surfaces
Tiga of the femur and tibio-fibula are
“connected by means of fibro-elas-
tic bands, which spring from the
latter bone and cross each other,
thus representing the /ig. cruciata.

Tibio-fibula of Rana escu-

lenta, twice nat. size,seen “AVON hte Lhe articular surfaces are more-
Mena js underextremity. over deepened by loose semilunar
7 Foramen nutritium, aan ee ih cartilages, corresponding with
¢ Anterior articular ex- | yarroweavities, the inter-articular cartilages of
e gprs Se elentlhe Sa | Peer the knee-joint of man. In addi-

t’” Grooveon malleolus in- ¢éThe two cylin- tion. on either side of the joint
ternus for tendon of ders of bone. : .

m. tibialis posticus. are found auxihary ligaments.

3. The foot (Fig. 47).

a. The ankle, ossa tarsi. The tarsus consists of two rows of
bones.

a. The proximal row consists of two long tubular bones (Fig.
47 ac), which are parallel to each other, and undoubtedly cor-
respond with the astragalus (/a/us) and caleaneum. ‘The bones
are separated in the middle, but approach each other at either end.
The outer of these bones (c) I have named calcaneum, following
Cuvier and Dugés; the inner, astragalus (a). The two bones are

ea ay eer

~ will be described below (see

——— ee

THE HIND-LIMB. : 51

surrounded and enclosed at
their anterior and posterior
extremities in a common epi-
physis of calcified cartilage,
which has the usual struc-
ture found elsewhere. The
ligamentum caleanei, which

Muscles of Foot, Fig. 88 /c),
may be regarded as an un-
attached process of the heel?.

8. The distal row of the
tarsals are all composed
of calcified cartilage. They
are :—

I. Os cuboideum (Fig. 47
ch), a flat plate of cartilage,
concave in front, convex
behind, placed between the
common epiphysis of the
astragalus and calecaneum
(ac) and the ossa metatarsi IT
and J/J. This corresponds,
as Dugés suggests, with the
separated os cuboideum and
cuneiforme III of other ba-
trachians, ¢.g. Bufo.

2. On the inner side of
the above, between the as-
tragalus and metatarsus I lies
a small body, concave in
front, convex behind, which
we may regard, with Dugés,
as the analogue of the os
naviculare (Fig. 47 2).

3. This latter supports a
cartilage which forms a pro-
jection on the inner border,
covered with skin. This

a Astragalus. h nie athena mond ee
j : ac Common epiphysis. of su en
consists of closely-united ¢ Calcaneunn. m Osca metacarpi
; ch Os cuboideum. n naviculare.
pieces, a small round, basal I to V First to fifth toe.

* Meckel, /.¢., II, p. 488, regards the cartilage in the tendo Achillis as such.
E2

52 THE BONES AND JOINTS.

piece (1), and a flattened beak-like piece (/’). Dugés considers
these pieces as the first and second ossa cuneiformia; I rather incline
to Meckel’s opinion that they represent a rudimentary hallux, the
first being the os metatarsi, the second a phalanx. Both are com-
posed of calcified cartilage ; in R. temporaria the lime-deposit seems
to be less than in &. owyrhinus and R. esculenta, and the projection
consequently softer !.

b. The metatarsal bones, ossa metatarsi (Fig. 47,mI-V). The
five ossa metatarsi are long, thin tubular bones, the anterior articular
extremities of which are broader above and narrow below, hence are
wedge-shaped, and anteriorly present flat surfaces for articulation
with the ¢arsus. The shafts are long and thin; the posterior
extremities have rounded heads. The comparative length of these
is as follows: the fourth is the longest, then come the third, fifth,
second, and first in order. In structure they resemble other tubular
bones.

ce. The phalanges, phalanges digitorum (Fig. 47). The total lengths
of the separate toes correspond with that of the ossa metatarsi, but
the distinctive differences are increased, partly by the difference in
number and partly by the varying lengths of the phalanges. The
first and second toes have each only two phalanges, the third and
fifth have each three, the fourth, which is the longest, has four.
The terminal phalanges are somewhat hooked towards the plantar
surface.

1 Tn the text these two cartilages are termed the ‘ supplemental toe.’

SCLES.

MU

.

THE MUSCLES.

LITERATURE.

v. Altena, see p. 13.

Anonymous, Ueber das Schultergeriist der Schildkréten mit den daran sitzenden
Muskeln. Isis, 1827. (Contains remarks on the shoulder-muscles of the frog.)

Carus, C. G. (1) Lehrbuch der vergleichenden Zootomie. 2nd Edit. Leipzig, 1834.
(2) Erlauterungstafeln zur vergleichenden Anatomie. 1 Part. 1826. (Muscles
of the Leg.)

Chappuis, Morphologische Stellung der kleinen hintern Kopfmuskeln. Zeit. f. Anat.
u, Entwickl. 1876. Vol. II, pages 287-297.

Cuvier, Legons d’anatomie comparée. Paris, 1835. Vols. I, II.

Dugés, Recherches anatomiques et physiologiques sur la déglutition dans les
Reptiles. Ext. des Annales des Sciences naturelles, Paris, 1827.

Dugés, Legons d’anatomie comparée. Paris, 1835.

Duméril and Bibron, Erpétologie générale ou Histoire complete des Reptiles. 1836.

Fihrbringer, Zur vergleichenden Anatomie d. Schultermuskeln. Jenaische Zeitschr.
1873. Vol. VII.

Klein, Beitrige zur Anatomie der ungeschwinzten Batrachier (Rana temporaria, L.):
in Jahrshefte des Vereins fiir vaterlindische Naturkunde in Wiirtemburg.
6 Jahrgang. 1850. Page 1.

Kuhl, Beitriige zur Zoologie der Rana esculenta: in Beitr. z. Zool. Frankfurt, a. M.
1820, Page 115.

de Mann, Vergelykende myologische en neurologische studien over Amphibien en
Vogels. Acad. Proefschrift. 1873.

de Mann, Myologie comparée de l’extrémité post. chez les amphibiens. Niederl.
arch. f. Zool. 1874. Vol. II.

Marshall, The Frog. London and Manchester. 2nd Edit. 1885. Pages 60-71.

Martin St. Ange, Annales des sciences naturelles. Vol: XXIV. 1831. Page 393.

Meckel, System der vergleichenden Anatomie. Halle, 1828. Vols. III and IV.

Pfeiffer, Zur Anatomie des Schultergiirtels und der Schultermuskeln bei Siiugethieren,
Voégeln und Amphibien. Giessen, 1854.

Rymer Jones, Article ‘ Reptiles’ in Todd’s Cyclop. of Anatomy and Physiology.
1847-1852. Vol. IV. Page 263.

Stannius, Handbuch der Anatomie der Wirbelthiere. Vol. II. Zootomie der Am-
phibien. Berlin, 1856.

Wagner, Icones Zootomicae. Leipzig, 1841.

Wagner, Lehrbuch der vergleichenden Anatomie. Leipzig, 1834-35.

Zenker, Batrachomyologia. Diss. Jena, 1825.

=

THE MUSCLES.

———

I. MUSCLES OF THE HEAD.

I. Muscies or tHe Eye.

1. UW. rectus inferior (Fig. 48 77’).

Dugés, post-orbito-sous-oculaire, n. 12.—Zenker, depressor oculi.

This muscle arises by a very thin,

almost thread-like tendon

from the parasphenoid, near the foramen opticum, and becomes rapidly

broader ; it lies beneath the tendon of
the membrana nictitans and a part of the
m. retractor bulbi: then runs forwards
and outwards to be attached into the
lower part of the circumference of the

eyeball.

2. W. rectus externus (Fig. 48 re).
Dugés, post-orbito-ex-oculaire, n. 14.
Arises by a thin, thread-like tendon
from the parasphenoid near the fora-
men opticum, internal to and a little be-
hind the m. rectus inferior : it then passes
obliquely outwards over the m. retractor
bulli and the tendon of the membrana
nictitans, to be inserted into the outer
and hinder part of the cireumferencé
of the eyeball.

3. WW. rectus internus (Fig. 48 rz).
Dugés, post-orbito-in-oculaire, n. 13.
A long, thin muscle, which arises by

Eye muscles of Rana esculenta, from
below.

On the right side (é. e. in the left eye)
the lev. bulbi(/) is taken away ; on
the left side it is still present.

iM. levator bulbi.

La M. lev. anguli seapulae
ot M. obliquus inferior,
os M. obliquus superior.
p M. pterygoideus.

r M. retractor bulbi.

re M. rectus externus.

1 First cervical vertebra.

a thread-like tendon from the parasphenoid at the inner and

56

THE MUSCLES.

hinder angle of the orbit, passes along its inner wall, and is in-
serted into the antero-internal part of the circumference of the

eyeball.

4. M. rectus superior (Fig. 49 78.).
Dugés, post-orbito-sous-oculaire.

Arises by a slender tendon from the fronto-parietal bone, widens

Fig. 49.

Eye-muscles of Rana esculenta, from

above.
n Membrana nictitans.

n’ Tendon of membrana nictitans.

p M. pterygoideus.
rs. M. rectus superior.
é M. temporalis.

rapidly, and runs forwards and out-
wards to be inserted into. the upper
part of the circumference of the Ju/bus.

5. M. obliquus inferior (Fig. 48 07).
Dugés, pré-sous-orbito-oculaire.

This muscle arises near the floor of
the orbital cavity, at the inner and an-
terior angle, from the palatine bone by
a thm and long tendon, runs under
Harder’s gland outwards and _back-
wards, and is inserted, almost at a right
angle with the axis of the eye, into
the anterior part of the cireumference
of the eyeball.

6. UM. obliquus superior (Fig. 48 os).
Dugés, pré-sus-orbito-oculaire, n. 7. |
The tendon of this small muscle arises from the inner end of the

Fig. 50.

Eye-muscles of Rana escu-
lenta, from below, the m,
recti and obliquihave been
removed,

n’ Tendon of membrana nic-
titans.

r M. retractor bulbi, lower
part.

x’ Second part of same.

palatine bone, near the origin of the m. obliquus
imferior, rans upwards, backwards, and out-
wards, and passes into a flat muscle, whicl:
rapidly becomes broader, and is inserted into
the upper surface of the eyeball.

7. WU. retractor bulli (Figs. 487, 507, 7’).

Dugés, orbito-post-oculaire or choanide, n. to.—
Zenker, m. opticus.

This muscle surrounds the optic nerve, and
is situated within the cone formed by the four
recti muscles; it consists of three portions,
which take their broad and fleshy (the recti
and obliqui arise by thin tendons) origins from
the under surface of the parasphenoid. The
first portion (Fig. 507) arises from the under
surface of the parasphenoid, nearly as far as the

MUSCLES OF THE HEAD. 57

middle line, is broad and fleshy, and covers, from below, the tendon
of the rectus externus, then runs forwards and outwards. The
second portion (7’), which lies over this and the tendon of the m.
rectus externus, has also a broad and fleshy origin, but runs more
directly forwards, slightly crossmg the preceding. The third
portion arises above the two others by a strong thin tendon from
the parasphenoid : it runs almost in the direction of the m. rectus
internus, but more directly forwards. The first two portions
pass more to the upper surface of the eyeball, the third more
to the under surface; consequently the whole muscle forms a
sheath surrounding the eyeball. The fibres to the upper surface
of the eyeball are inserted somewhat in front of the equator of
the eyeball, those to the under surface somewhat behind it.

8. U. levator bulbi, Duges (Figs. 48 7, 51 J, 522).
Dugés, fronto-pterygoidien, n. 9.—Klein, sustentator bulbi.

There is no bony floor to the orbital cavity, and the oral and orbital
cavities are only separated by soft tissues; these are :—the mucous
membrane of the mouth,

a thin fascia, and above

this the muscle under Fig. 51.
consideration. The fibres P

of this muscle run from 5
before and from the inner
side obliquely backwards
and outwards, below all
the remaining muscles of

the re, With, UNE ExCOP-— oo Laake th, weak the
tion of the origin of the —skull_ and orbital cavities of

. Rana esculenta.
m. retractor bulbi, and
6 Bulb of eye. M., levator dulbi of Rana
the tendons of the m. ¢ Skulleavity. esculenta; een from
A . : g Mucous membrane. above; the eyeball
pages inferior, and a M levator bulbi. ee oe th ke
ma: nlerddbideus:: m Upper jaw. been ed.
ergy? a ey n% Membrana nictitans. agen

arise on the inner side 2»’ Continuation of same to the sii ver, reer Hg
lower eyelid. oe eee

from the upper and outer , Upper eyelid. ¢- M. levator bulbi.
border of the fronto- 4 De a.
parietal bone (Fig. 51), tiga

also from the transverse portion of the parasphenoid and ptery-
goid bones, anteriorly from the sphenethmoid and palatine bones;
they run first downwards, then, in the direction indicated, under-

58 THE MUSCLES.

neath the eye; and are inserted externally by means of tendinous
fibres into the superior border of the upper jaw.

9. From the foregoimg muscle certain fibres pass to the lower
eyelid, which may be regarded as a depressor palpebrae inferioris
(Fig. 52 d.p).

Manz" has described a muscle as depressor palpebrae inferioris
which arises in the neighbourhood of the external angle of the
eye, somewhat behind and below the lower border of the orbit, thence
passes obliquely upwards to be inserted into the lower eyelid. This
description is right as regards the insertion, but needs correction
as regards the origin. The muscle is attached to the orbital border
in so far that the tendinous expansion, into which the levator bulbi
passes at its external border, is attached into the upper jaw; this
bundle splits off from the upper surface of the levator bulbi at its
middle, and runs outwards on the under surface of the eyeball to the
hinder part of the lower eyelid.

10. Tendon of the membrana nictitans® (Fig. 53%’). The
pigmented free border of the nictitating membrane passes, at the
inner and outer angles of the eye, into a ten-
don which passes for some distance through
fibrous tissue, then descends to the under
surface of the eyeball and joins that of the
opposite side, so that the free border of the
eyelid, together with this tendon, form a com-
plete ring. The tendinous part of the ring,
which is thin and _ thread-like, is found
on the under surface of the eyeball, and lies
under the m. retractor bulbi, and is bound to
Bye-muscles of Rana escu. ‘His muscle by connective tissue. Manz is

lenta, from below, the m. right in saying that the two muscles described
recti and obliqui have x F .
Raastieanitred: by Dugés as /evatores palpebrae inferiores (or-
gig poearurettice bito-palpebral anterieur and posterieur, n. 5
y M, retractor bulbi, lower and 6) do not exist; as is also the suggestion
BL sk oF de pote that he has confounded the tendon of the
nictitating membrane with these; this is
clearly shown in the figure in Plate VI of Dugés. With regard
to the actions of these eye-muscles, it is plain that the four straight

Fig. 53.

~~
»okI2 ©

1 Manz, Berichte der naturf. Gesellschaft zu Freiburg, 2 Band, 4 Heft, 1862,
p- 391.

? Compare Manz, J. c.

es eis ee

_ site one. It brings together the pro-

MUSCLES OF THE HEAD. 59

and two oblique muscles rotate the eyeball about three axes, one
the axis of the eye, one vertical, and the third passing from behind
forwards and inwards. The m. retractor pulls the eyeball into
the orbital cavity backwards and downwards, while the /evator
raises it.

There is less agreement abont the movements of the eyelids, or
rather of the lower eyelid, for the upper has no independent
movements. Dugés (/.c.) says that the two muscles, which he con-
siders to be /evatores palpebrae inferiores, and which, according to
him, are connected with the m. retractor bulbi, draw up the lid as it
is being drawn backwards and downwards by the latter muscle.
The depression of the lid on the relaxation of the retractor and
projection of the eyeball is due simply to elasticity. Manz?, on the
contrary, has shown that the sinking of the eyeball by the con-
traction of the retractor must necessarily cause a rising of the
nictitating membrane, as its tendons are attached to that muscle
and so must follow its movements.

The depression of the lower lid occurs simultaneously with the
raising of the eyeball by means of the m. levator bulli, through the
contraction of the m. depressor palpebrae inferioris, which proceeds
from that muscle; this is easily understood, as they are but parts

of the same muscle.

II. Muscies or THE Facer.

11. UW. intermazillaris s. dilatator narium (Fig. 54 im).
Dugés, intermaxilaire, n. 1.—Zenker, intermaxillaris medius.
This small muscle lies in the space
between the vertical processes of the
two premaxillary bones, and consists of
obliquely-crossing fibres arignmg from,
the one bone and inserted into the oppo-

cesses of the intermaxillary bones, so
that their upper extremities approach

each other. At the same time, the join) muscles of Rana vsculenta.
cartilaginous nasal coverings or wings am Cartilaginous nasal alae. _
(an) diverge and the nares expand; “ V*tss! Procos of premaailiary

hence w@ may regard this muscle as im ™. intermaxillaris.
in M_ lateralis narium.

corresponding to a dilatator narium. n Cartilaginous nose capsule.
1 Z.¢., p. 4.

im

60 THE MUSCLES.

12. MW. lateralis narium (Ecker), (Fig. 54).

Zenker, m. intermaxillaris lateralis—Klein, m. nasalis inferior.—
Dugés, sus-maxillo-pré-nasal, n. 2.

This small muscle occupies the space between the anterior portion
of the maxillary bone and the ascending process of the premaxillary
bone. It arises from the maxillary, and ascends obliquely forwards
to be inserted into the outer border of the ascending process of the
premaxillary bone. It is antagonistic to the foregoing.

A third muscle is described by Dugés as sus-mawillo-post-nasal,
n. 3 (nasalis externus, Klein); according to him it passes from the
proc. nasalis of the maxillary bone to the outer border of the nasal
opening, which it widens. According to Klein (/.c., p. 9), this
muscle in 2. temporaria runs to the upper border of the maxillary bone
beneath the lower eyelid, and is long and narrow. I have, however,
never been able to find muscular fibre in this situation.

III. Muscizes or tHE Lower Jaw.

13. MW. depressor mawil-
lae inferioris, Carus, Zenker
(Figs. 55, 56, 63 d.m.).

Cuvier, /.c., II, 141, digas-

tricus.—Dugés, sus-occipito-
dorso-angulaire, 32.

This is a strong, trian-
gular muscle, wide above,
pointed below. It is placed
between the head and the
shoulder-blade. It arises in
two portions; the greater,
from the fascia dorsalis
(2 ), covers the scapula, and
passes inwards and back-
wards over the muscles of
the back ; anteriorly it passes

Muscles of the back and shoulder. over the m. temporalis and
c M. cucullaris. is attached to the fronto-

dm,dm ,M, depressor maxillae, arising from the fascia i
dorsalis. On the right side it is cut through parietal and squamosal,

: and reflected. . ;

PSCaene Meee being continued to the
Sd’ Same cut near the spinous processes. fascia of the uper eyelid,
i ,M. infraspinatus. 3

ia’ M, levator anguli scapulae. : The second part is smaller,
ld /M. latissimus dorsi.

r M. retrahens scapulae. and arses by fleshy fibres
sc M. sternocleidomastoideus. from the postero-superior

—

EE

OE eS eS
: 1

MUSCLES OF THE HEAD. 61

arm of the squamosal, and from the posterior and inferior border
of the cartilaginous tympanic ring. The two parts unite and are
inserted into the hinder angle of the lower jaw. Cuvier correctly
considers that only the anterior portion corresponds to the digastri-
cus, the posterior answering to the m. cervico-maxillaris of snakes.
It draws the lower jaw down and opens the mouth.

14. M. temporalis (Figs. 49, 52, 56, 57 ¢).
Cuvier, m. temporulis, I, l.¢., p.138.—Dugés, sous-rupéo-temporo-coronoidien.

This muscle, together with the m. pterygoideus, occupies the space
between the prootic and the eyeball; it arises by the greater
part of its fibres from the .
upper surface of the pro-
otic; it passes, narrowing,
beneath the anterior arm of
the squamosal, then over
the pterygoid bone, between
this and the maxillary and
quadrato-jugal, receiving on
the way other fibres which
arise from the anterior border
of the inferior arm of the’
squamosal and from the
anterior circumference of the
tympanic ring. The collected 4 yy jettoiaeus
fibres end in a broad, flat dm M. depressor maxillae, its origin where covering
tendon, which is inserted into uw Mninimmpni
the inner surface of the so- ™ M- maseter.

b t M. temporalis, origin.
called proce. coronoideus. ’ Lower portion of same.

Muscles of the lower jaw of Rana esculenta.

15. M. pterygoideus (Figs. 49 p, 52, 57 pt).

Cuvier, m. temporalis, II, l. e.—Zenker, m. massetericus, 1. c., p..25.—
Dugés, pré-rupéo-pterygo-maxillaire, 31.

This is partly covered by the foregoing, and lies between it and
the eyeball. It arises at the inner wall of the orbit from the
frontoparietal, and from that portion of the prootic which may be
regarded as the a/a magna, above the m. retractor bulbi. The muscle
is broad, and compressed from before backwards: it runs down-
wards covered by the m. temporalis, and soon passes into a long,
thin tendon (Fig. 57 pt), which is inserted, behind the m. temporalis
and immediately in front of the joint, into the inner surface of the
lower jaw.

62 THE MUSCLES.

16. MM. masseter (Figs. 56, 57 m).
Dugés, zygomato-maxillaire, n. 29.
Arises as a somewhat broad muscle from the horizontal process of
the quadrato-jugal and is inserted
into the outer side of the lower
jaw, opposite the insertion of the
m. temporalis.

Fig. 57.

Y 17. M. submazitlaris (Figs. 58,

59, 61 sm, sm’).
Cuvier, m. mylo-hyoideus, l.c., I,
536. — Zenker, mylo-sternoideus,
p- 25. — Dugés, sous-maxillaire, n.

IB.

This muscle forms the floor of
the mouth as does the mylo-
Muscles of the lower jaw of Rana esculenta, hy ovdeus man ; it 1S, however,

dm M. depressor maxillae cut through and not inserted into the hyoid bone.
reflected, :

Pa 'al: levator anguiltickpalan It arises—1. From the whole of
i.d. M. latiss. dorsi, cut through and reflected. the inner surface of the upper
m M. masseter. ie hi

pt M. pterygoideus. border of the lower jaw', except
s Scapula. :

s’ Suprascapula. near the angle (Fig. 58 si) 4

s.c. M. sternocleidomastoidens.
tt M. temporalis cut through and reflected.

2. By asmall portion (Figs. 58,
59, 61 sm’) near the skull, from
the cartilaginous anterior cornu of the hyoid-bone which projects
from the cartilaginous part of the prootic bone. This portion
descends along the cornu to unite with the other portion. The
two together form a membranous layer, the fibres of which run
transversely and meet in a band of connective tissue along the
middle line, forming a kind of Zinea alba. The sheath runs for-
wards to the most projecting part of the lower jaw superficially to
the m. submentalis. Slightly in front of its posterior border the
muscle is attached in its whole breadth to the skin of the throat
by a fine lamella of connective tissue, which is not always complete.
The posterior border of the muscle is attached to a fascia, which.
passes between the deeper muscles and is attached to these. It is
known that this muscle plays an important part in the movements
of respiration and swallowing ; but its precise action has not yet
been worked out.

1 A second origin from the lower border of the mandible, described by Klein, is

not to be found. The appearance is due to the exit of vessels and nerves from the
. groove between the mandible and the muscle.

MUSCLES OF THE HEAD. 63

y 18. WM. submentalis (Fig. 59 smt).
Cuvier, transversus, 1. c., p. 588. —Dugés, 4, sous-mentonnier. — Zenker,
m. lingualis (incorrectly brought into connection with m. hyoglossus).
This small muscle lies in the anterior angle of the lower jaw
between the dentary bones. It consists of transverse fibres which
Fig. 58.

4

Muscles of the throat, chest, and abdomen of Rana esculenta.
sm M. submaxillaris.
sm’ Hinder portion of same arising from the anterior cornu of the hyoid bone.

(For other references see page 68.)
pass from one bone to the other. Below it is covered by the most
anterior portion of the m. submarillaris.
Its action is to approximate the sides of the lower jaw: according’
to Dugés (/.¢., p. 123), it assists in closing the nostrils, by drawing
together the sides of the lower jaw and thus raising the premaxillae.

64 THE MUSCLES.

TV. Muscies or tHe Hyorp Bone anp tHe Tonaun.

y 19. MW. geniohyoideus (Figs. 59 gh, 60 gh).

Cuvier, IV, 1, 536.—Dugés, n. 16.—Zenker, p. 30.—M. St. Ange, I. ¢.,

Pl. XXVI, f. 1, 13, p. 423.

Arises from the lower jaw in two portions, the one from near
the middle line above the m. submentalis, the other more externally

Fig. 59.

smt

mq

Muscles of the hyoid bone and the tongue of Rana
esculenta.
The m, submaxillaris has been removed close to
its insertion.
em’ Origin of the hinder portion of same from
the hyoid bone.
gh M. geniohyoideus.
gh’ External portion of same.
gh” Internal portion of same.

H . Body of hyoid bone.
H’ Anterior horn,
hg M. hyoglossus.
oh M. omoltyoideus.
ph Mm. petrohyoidei.

sh M. sternohyoideus.

‘sh! External origin of same.
sh” Internal origin of same.
sm M. submaxillaris,
sm’ Origin of hinder portion of same,
smt M. submentalis.

from the upper border of the
lower jaw. The two parts unite
to form a long, flat muscle,
which lies on the ventral sur-
face of the body of the hyoid
bone, and divides posteriorly
into two portions. One of these,

the median (Figs. 59, 60gh” i,

is inserted into the inner border
of the posterior horn of the
hyoid bone, and is here attached
to a fascia which covers the m.
hyoglossus from beneath, By
the same fascia the muscles of
opposite sides are connected
in the space between-the two
posterior cornua, The lateral
division (Figs. 59, 60 gh’) is
attached to the posterior carti-
laginous process of the hyoid

bone.

20. I. sternohyoideus (Figs.
59,60 sh).

Cuvier, IV, 1, 538 (pubio-hyoi-
deus). — Dugés, n. 17, sterno-
xipho-hyoidien.— Zenker, p. 30.

This muscle forms the cer-
vical part of the m. rectus

abdominis and is, in fact, a direct continuation of it. It arises by
an inner portion (Fig. 59 s#’”) from the upper surface of the inner
extremity of the ‘coracoid and from the xiphisternum, while the

MUSCLES OF THE HEAD. 65

outer portion (sk’) is an immediate continuation of the m. rectus
abdominis, which passes into this

muscle at about the fifth zzscrip-

tio tendinea. The muscle passes

forwards on the upper surface of gh
the coracoid and of the clavicle,
under the pericardium towards
the hyoid bone; here the muscle,
hitherto horizontal, suddenly be-
comes (compare Fig. 60) ver-
tical, and passes between the
two insertions of the m. genio-
hyoideus, and is inserted for a

considerable length into the lower hg’ he a”
surface of the hyoid bone and the oe
anterior extremity of the posterior -
i: Muscles of the tongue and of the hyoid bone of
Rana esculenta, from below.

cornu.
gh M. geniohyoideus.

gh’ External origin

gh” Internal origin | tna
H_ Body of hyoid.

H’ Anterior cornu.

H” Posterior cornu.

21. WM. omohyoideus (Figs. 59,
60 oh).

_ Cuvier, /.c., p. 539-—Dugés, n. 18,
interscapulo-hyoidien ou omo-
hyoidien. — Zenker, p. 31.—
M. St. Ange, /. c.

Arises from the anterior border

hg M. hyoglossus.

hg’ Hinder origin of same.

oh M. omohyoideus.

ph.1, 2, 3, 4, first, second, third, and fourth
m. petrohyoideus.

sh M. sternohyoideus.

ee

of the bony scapula, and is in-
serted into the outer part of the ventral aes 3 of the body of the
hyoid : it is partially covered by the m. sternohyoideus.

22. M. petrohyoideus anterior (Ecker), (Fig. 61 ph1).

Dugés, 10, rupéo-cérato-hyoidien.—Zenker, m. pelro-ceraus? p. 30.—
Klein, basio-hyoideus, 1. c., p. 71.

_ A thin, flat. muscle, narrow above, but broadening rapidly
below, which arising from the outer extremity of the prootic
bone, partially surrounds the pharynx below, into which some of
its fibres are inserted; it is attached to the ventral surface
of the body of the hyoid bone, near the lateral notch. The
chief action of this muscle appears to be that of a m. constrictor

66 THE MUSCLES.

23, 24, 25. Mm. petrohyoidei posteriores (Ecker), (Figs. 61
ph2, 3, 4).

tiie Cuvier, mm. stylohyoidei, l.c., p. 537.—Dugés, 20, 21, 22, masto-hyoi-
“- deus (Fig. 4).— Zenker, petro-hyoideus superior and inferior.—
Klein, stylo-hyoideus, l.c., p. 18. ,
These are three long, thin muscles, which lie nearly parallel to
one another, and run from the prootic bone to the posterior cornu
of the hyoid bone. All three arise,
Hig. 6x. covered by the m. sternocleidomastoi-
N deus, from the lateral extremity of
the prootic, pass round the pharynx
and are attached, the m. petrohyoideus
posterior primus (Fig. 61 ph 2) to the
anterior extremity, the secundus (Fig.
61 ph 3) to the middle ; and the fertius
(Fig. 61 ph 4) to the hinder extremity
of the posterior horn of the hyoid
bone.

sm

y 26. MW. hyoglossus (Figs. 59, 60,°

\ 61 hg).
Muscles of the hyoid bone of Rana escu- Cuvier, /. c., p. 588.—Dugés, 24, hyo-glosse.
lenta, seen from the right side and ° F
bale: Arises from the bony posterior ex-
H’ Anterior cornu. tremity of the hinder process of the
H” Posterior cornu. ‘ ;
ho: Me Thyoglonsad. hyoid bone (/g’). The muscles of the

Lier gh Fe pehcn N two sides pass forwards and converge

ph2, 3.4 Mm. petrohyoidei posteriores. to the middle line, where they unite.

sm M. submaxillaris.

sm’ Hinder portion of same. The azygos muscle thus formed runs
forwards on the ventral surface of the

hyoid bone, between the mm. geniohyoidei, over the anterior border .

of the hyoid, and passes into the tongue, where it turns backwards

and runs to the tip. (For action, see tongue.)

27. M. genioglossus.

- Cuvier, /.¢., p. 587.—Meckel, /. c., 1V, 339.—Dugés, 23, genio-glosse.

Arises above the insertion of the m. geniohyoideus on either side
near the middle line from the two anterior bones of the lower jaw.
The two origins quickly unite to form a thick, very firm muscular
belly, which in its course backwards rapidly thins, and is distributed
by numerous bundles ; decussating with the fibres of the m. hyog/ossus
at an acute angie, it runs on to the anterior extremity of the tongue.

ih a De — aa ot

—_—_ ~~

Se ee

oo

MUSCLES OF THE TRUNK. 67

II. MUSCLES OF THE TRUNK.

I. Muscies oF THE ABDOMEN.

In the formation of the abdominal wall the following muscles
take part :—(1i) m. rectus abdominis, (2) m. obliquus externus, (3) m.
obliguus internus, (4) the portia abdominalis of the m. pectoralis.
Above, the m. obliquus internus forms a kind of diaphragm, partially
separating the abdominal from the thoracic cavity (p. 70).

“te 28. WM. rectus abdominis (Fig. 62 7).

Dugés, pubio-thoracique, n. 52.

These muscles, situated on either side of the middle line of the
abdomen, are as a rule traversed by five notched inscriptiones ten-
dineae. Each muscle arises, by a narrow, strong tendon, from the
inferior border of the pubes, passes forwards, and quickly widening,
divides at the second inscriptio /endinea (counting from behind) into
two portions.

(2) The Outer portion (Fig. 62 r) runs into the portio abdominalis of
the m. pectoralis, and forms the greater lateral division of that muscle.

(4) The Inner (7’) continues as the m. rectus abdominis and gradu-
ally narrows anteriorly. At the sternum some of the fibres (the
median) are inserted into the dorsal surface of the cartilaginous
plate of the xiphisternum, while the greater part of the muscle con-
tinues forwards over the coracoid to become the m. sternohyoideus

at about the fifth inscriptio tendinea (p. 64).

29. M. obliquus externus (Fig. 63 oe, oe’).
Zenker, /. c., p. 31, m. obliquus.—Dugés, dorso-sous-abdominal, n. 54.

The m. obliquus externus arises from—

(a) The aponeurosis covering the long muscles of the back, and
by this from the spinous processes. The anterior edge of the
m. obliquus externus covers the posterior edge of the m. /atissimus
dorsi, which arises from the inferior, ventral surface of the aponeu-
rosis. The aponeurosis also divides laterally into two parts, one of
which, the posterior, passes into the obliguus externus, while the
anterior forms the tendon of origin of the depressor masxillae inf.
(dm) (compare Fig. 66).

(4) A second, narrow portion, portio omo-abdominalis (Fig. 63 oe’)

F2

68

(m. wipho-adscapulaire, Dugés, n. 62), arises from the posterior
border of the scapula by a thin tendon, and becomes broader as it
; Fig. 62.

THE MUSCLES.

Muscles of the chest, throat and belly of Rana esculenta.

ch

sh
sm
sm
sr

U

runs downwards and backwards, to join the anterior border of the

M. coraco-humeralis,

M. deltoideus,.

M. obliquus abdom., internus.
M. obliq. abdom. externus. *
Scapular portion of same.

M. omohyoideus. f
Port. sternalis anterior of m. pectoralis.
Port, sternalis posterior of same.
Port. abdominalis of same.

M. rectus abdominis. |

Inner portion of same.

M., sternohyoideus.

M. submaxillaris.

Hyoid origin of same.

M. sternoradialis,

other and larger portion.

‘ .
es

ee eee

ee

—

a ey

MUSCLES OF THE TRUNK. 69

The whole muscle is attached by its most anterior fibres to the
cartilage of the xiphisternum, the rest passing into an aponeurosis

Fig. 63.

oe oe’ ss

Muscles of trunk of Rana esculenta, from the right side.

ed M. cutaneus femoris,

d M.deltoideuz, .

d.m. M. depressor maxillae.

M. infraspinatus,

M. latiss. dorsi.

M. obliquus abdom. externus.
Scapular origin of same.

M. subscapularis.

M. triceps brachii.

“BRRE™

which, inseparably connected with the tzscriptiones tendineae, traverses
the lower surface of the m. rectus abdominalis to the linea alba.

30. WU. obliquus internus (and transversus), (Figs. 64, 65 07).
Dugés, ileo-transverso-sous-sternal, p. 53.—Zenker, transversus, l.c.,
p- 31.—Kuhl, transversus, l. c., p. 116.

This muscle corresponds with the combined ob/iguus internus and
transversus, and has therefore been described either as the one or the
other, by various authors.

The fibres arise tendingusly—

a. From the transverse processes of the vertebrae from the

fourth backwards, and from the fascia covering the mm. intertrans-

versarii.

b. From the iliac bone, bya strong tendon from its upper border,
and by a few weaker fibres from its outer surface. The latter fibres
are covered by the former, and these end posteriorly in a sharp_
concave border.

The muscular bundles diverge from these points, some running
forwards, some backwards; the former are only partially covered
by the portio omo-abdominalis of the m. obliquus externus (compare ,

70 THE MUSCLES.

Figs. 62, 63), in front of the anterior edge of that muscle. The
posterior border of the muscle is uncovered. .

Fig. 64.

Second layer of abdominal muscles of Rana esculenta, from the right side and below. The
m. obliquus externus and the right anterior extremity has been removed.

dm M. depressor maxillae.

hg M. hyoglossus,

ld M. Jatissimus dorsi and infraspinatus,

oi M. obliquus internus.

oi’ Insertion of third portion of same.

oi” Second portion inserted into the pharynx.
pe Pericardium.

ph4, M. petrohyoideus quartus.

yr M., rectus abdominis,

ss M. subscapularis.

The insertions of the muscle are very various, and as a conse-
quence very various functions are accomplished by it.

a. The most anterior part of the muscle (Fig. 65 0¢’”), the fibres
of which run forwards, is attached—

1. Partly to the xiphisternum and the coracoid.

2. A second portion, viz. that arising from the transverse pro-
cesses of the fourth vertebra (Fig. 64 02”), surrounds the pharynx
like a diaphragm (Fig. 65 0¢), and is attached to its side as far as
the dorsal aspect (Fig. 6502’). This portion is lightly separated
from the following.

3. A third portion, placed behind the preceding, runs from the
pharynx over the pericardium (Fig. 64 pe), and is attached to this
nearly as far as the middle line (Figs. 64 02 and 65 oi”), resting
on the sternum, the m. rectus and m. sterno-fyoideus. The lines of
insertion of the muscles of opposite sides form an angle, open in
front. In the thin borders of this portion the muscular bundles lie
almost entirely in simple layers, and they are therefore well adapted
for microscopical purposes.

b. The middle and posterior portions of the nies pass down-

{
“

MUSCLES OF THE TRUNK. 71

wards and slightly backwards, towards the outer border of the

_ m. rectus; there they pass into a tendon which, for the most part,
runs on the upper surface of the rectus to the linea alba.

II. Muscies or THE Back.

The muscles of the back are covered by a fascia, the fascia dor-
salis (Fig. 66 f7/), attached to the spinous processes of the vertebrae.
Anteriorly, where it covers the m. tempora/is, it is attached to the
frontoparietal and squamosal bones, posteriorly to the superior border
of the iliac bones and the extremity of the urostyle. The posterior part,
which covers the origins of the
m. longissimus dorsi, of the m.
coccygeo-iliacus, and of the
coccygeo-lumbaris, is especially
strong. From the anterior
part several muscles arise la-
terally, viz. a portion of the
m. obliquus abdominalis exter-
nus, of the m. latissimus dorsi,
and of the m. depressor maxillae
inferioris. Inthe uppermost }
layer, immediately covered by
the fascia dorsalis, lie the m.
cucullaris, the m. retrahens
scapulae, the m. latissimus ©. obliquus internus, showing its attachments
dorsi arising from the fascia , _ Xiphisternum.
itself, and the scapula with ‘OREO tornns
its muscles ; then come the Fibres of m. obliq. int., which are inserted into
long muscles of the back ; and oi” ov Sage eee A tie sfeinad Woodard
in the third and deepest layer» p.Suua

Fig. 65.

- the short muscles of the back. + M. rectus abdominis.

The individual muscles are as follows :—

A. Lime Moscres or tue Back (for moving the shoulder-
girdle and arm).
81. MW. cucullaris (Fig. 66 c).
Cuvier, angularis.—Dugés, n. 38, sous-occipito adscapulaire.—Zenker,
levator seapulae sublimis.
In order to see this muscle, it is necessary to separate the fascia
dorsalis from the spines of the vertebrae and to turn it back with
the m. depressor maxillae inf. arising from it. It is then seen to

72 THE MUSCLES.

rise from the posterior surface of the exoccipital as far as the
middle line ; the muscles of the two sides run backwards, diverging
each from the other, so as to form an angle, and are then attached
on each side to the anterior superior angle of the suprascapula at
its under surface and median border. ald

Cuvier considers this muscle as the analogue of the m. levator
anguli scapulae. Dugés and Meckel consider it to be the anterior part
of the m. cucudlaris, the former thinking the posterior part of the
muscle to be the m.rhomboideus. I cannot agree with these opinions,
and I regard the muscle as simply representing the m. cucullaris of -
man (Ecker).

32. M. latissimus dorsi (Figs. 56, 66 dd).
Dugés, n. 66, lombo-huméral.—Zenker, depressor brachii.

This thin, triangular muscle arises from the ventral surface of the
fascia dorsalis, and is posteriorly covered in part by the anterior
border of the m. obliquus abdominis externus. The muscle becomes
narrower towards the sides, and passes into a flat tendon, which
blends with that of the m. infraspinatus, and is attached to the
outer surface of the crista
deltoidea of the humerus by
a triangular expansion.

33. MW. retrahens scapu-
lae (Kicker), (Fig. 66 7).
Dugés, n. £9, lombo-adscapulaire.
—Klein, m. rhomboideus, l. c.,
p. 26.— Zenker, omoplateus
rectus ? p. 37, l.c.— Kuhl, /.c.,
124, retrahens rhomboideus,

This flat, oblong muscle
arises from the transverse
process of the fourth verte-
bra, and is connected with
the third tendinous inscrip-
tion (counting from before)

Muscles of the back and shoulder-blade. of the m. longiss. dorsi. Pos-
Ao ey cama teriorly its origin forms a

dm,M. depressor maxillae arising from the fascia dor-

salis, cut through and reflected on the right side. @onyvex border, whence it
Jd Fascia dorsalis. :

fd’ Same cut through at the spines. runs forwards and to the
. fi eee side ; it is inserted into the
l.a_ M. levator anguli scapulae. 2

id_/M. Latissimus dorsi. ’ ventral surface of the supra-

y M. retrahens scapulae. . ] 2 f : 1, ‘ 1 Be
se M. sternocleidomastoideus. scapula, near its inner border.

MUSCLES OF THE TRUNK. 78

This muscle lies near the m. serratus or transv. scap. tertius (Fig.

. 68 és”), and has an analogous position. It would, therefore, possibly

be more correct to regard it also as a m. serratus. It arises
from parts which represent ribs, and is inserted into the scapula.
It has, at any rate, no analogy to the m. cucudlaris, with which
Dugés connects it, nor with the m. rhomboideus, which Kleim holds
it to be, as it does not arise from spinous processes.

B. Lone Muscres or rue Bacx.

34. M. extensor dorsi communis (Fig. 67 /g.d.).

Dugés, n. 33-40, masse des muscles surspinaux devis¢e en huit faisceaux
principaux: 1. vertebro-sus-occipital, 2-5. transverso-spinaux, 6.
transverso-coccyg., 7. sacro-coccygien, 8. ileo-coceygien. The muscles
1-7 form the lombo-costal, 8 the ischicoceyg., Cuv.— Zenker, m. sa-

crolumbaris.—Klein, longiss. dorsi, coccygeo-lumb., coccyg.-iliac.
This muscular mass is covered by the fascia dorsalis, the m. cucul-
laris and retrahens scapula, and the suprascapula : it corresponds with
(1) the m. ileo-costalis and longissimus dorsi, dorsi and cervicis (Henle);
(2) the semispinalis and spinalis (Henle).
The following separate portions may be made out :—
35. (1) UW. longiss. dorsi (Fig. 67 /g.d.).

This muscle arises from the most anterior part of the urostyle, runs
forwards near the middle line, separated from the muscle of the
opposite side by the spinous processes of the vertebrae. The inner
portion passes over the posterior spinous processes without being
connected with them, as far as the fifth, it is then imsertéd into the
succeeding spines as far as the exoccipital bone. The lateral portion
runs outwards and forwards to be attached to the transverse pro-
cesses and oblique processes of all the vertebrae, from the sixth
forwards, while accessory muscular slips arise from the transverse
processes and from the anterior spinous processes which, merging
in the general muscle-mass, are inserted with this into the occiput.

The muscle is subdivided by a series of wavy, tendinous par-
titions (Fig. 67), which arise from ‘the transverse processes, and
traverse the muscle in planes, the upper surfaces of which are
directed upwards and forwards. This arrangement of the muscle
indicates its relation with the lateral trunk muscles of fish and
fish-like amphibians.

36. (2) UW. coccygeo-sacralis (Fig. 67 ¢.1.).

This muscle is partially covered by the preceding, it arises from

the lateral surfaces of the anterior half of the urostyle; from this

74 -

THE MUSCLES.

origin the fibres pass forwards and outwards to be inserted in two

portions, the anterior set into the arch and the posterior set into the .
transverse process of the last vertebra.

The former may be re-

garded as m. intercruralis, the latter as m. intertransversarius.

Fig. 67.

¢

Ui if “ll \)
fp | j 1] NN
q ilk sais) \\\

i \ | ti :
| ~ i Ny iS
i.c.i. a mi
i.c.s. ls MM iN
foal te ig.d.
; Coulis i —
‘ ai nit Yy
on SS ine iu ZA\
My = Dp ZZ
; ZZ Nee il.
0.1. — ES 2
ZEN: \W=
-- cl
Ay \ ' Cd,
dD ' gl.

er
. 4 \
Muscles of the back and pelvic girdle of Rana esculenta.

ci. M. coccygeo-iliacus/

, ¢.l, M. coccygeo-sacralis.,
g.l. M. glutaeus.
é MM. intertransversarii.
v MM. intercrurales.
ici. M. intertransv. capitis inferior.
i.c.s. M. intertr. cap. sup.

E $t, M. ilio-lumbaris.
ig.d M. longissimus dorsi.
oi, M. obliq. internus.
t M, temporalis.

37. (3) I. coccygeo-
dliacus {Fig. 67 ¢.1.).
This muscle arises

from nearly the whole
length of the lateral] sur-

_ face of the urostyle, the

anterior portion being
concealed by the preced-
ing muscle. The fibres
pass outwards and for-
wards to be inserted into
the anterior two-thirds of
the inner surface of the
ilium.

88. I. ilio-lumbaris
(Klein), (Fig. 67 #.).
Duges, n. 51, transverso-ili-

aque.—Cuvier, Zenker,
etc., guadr. lumborum.

Evidently represents
the guadratus lumborum
of human anatomy; it
takes its origin from
the anterior extremity
of the ilium, and runs
forwards to be inserted
into the transverse pro-
cesses of the vertebrae
from the seventh to the
fourth,

Ss —_ ee

MUSCLES OF THE ANTERIOR EXTREMITY. o

C. Ssort Moscres or rar Back.
39. W. intertransversarius capitis superior (Ecker), (Fig.67 i.c.s.)-
Dugés, n. 41, ex,ccipito-transversaire sup.
A small muscle arising from the prootic: it lies above the
levator anguli scapulae, and is inserted into the transverse process of
the second vertebra.

40. W. intertransversarius capitis inferior (Fig. 67 1.c.i.).
Dugés, n. 42, ex-occipito-transv. inf.

This muscle lies on the ventral surface of the preceding one, but
is easily separable from it; it arises from the angle of the prootic
and is inserted, together with the preceding muscle, into the
transverse process of the third vertebra. The x. vagus passes out-
wards between these two muscles.

41, MM. intertransversarii dorsi (Fig. 67 7).
Dugés, n. 43 to 50, intertransversaires.

Seven small muscles, placed between adjacent transverse pro-
cesses of the vertebrae; from the second to the last, in continuity
with the muscles last mentioned. :

42. MM. intercrurales (Ecker), (Fig. 67 7).
Klein, p. 29, interspinales, interobliqui.

Those muscular fibres found between the arches of adjacent
vertebrae are so named. On account of the shortness of the
spinous processes they can scarcely be named m. interspinales.

Ill. MUSCLES OF THE ANTERIOR EXTREMITY.

I. Muscies oF THE SHOULDER-GIRDLE.

A. Dorsat Muescres or trae Snovtper-Biave.

(L.) Muscles arising from the head or trunk, and inserted into
the scapulae, which they act upon primarily, and upon the shoulder-
girdles secondarily.

Some of these muscles, such as m. cucullaris and retrahens, are
situated on the back, and have already been described with the
muscles of that region. Others are attached partly to the under-
surfaces of the scapulae and are only visible from below ; they are
best seen in such a preparation as is shown in Fig. 68, made by
cutting through the sternum in.the middle line, and reflecting each
half outwards.

76 THE MUSCLES.

(a) Muscles which arise from the skull.

43. M. levator anguli scapulae (Fig. 68 /a).

Dugés, sous-occipito-adscapulaire, n. 60.—Zenker, protractor scapulae,
Pl. I, Fig. 5.—Cuvier, Lecons I, p. 379, describes this muscle as part
of the m. serratus anticus magnus,

A fairly strong muscle, which has a broad origin from the prootic
and exoccipital bones as far as the foramen magnum, a few fibres
are also attached to the lateral portions of the parasphenoid, The
fibres run backwards and outwards, first in a frontal plane and
then in a sagittal plane, to be inserted into the under surface of
the suprascapula near the posterior border, where it encloses the
hinder border of the m. interscapularis.

Its action is to draw the shoulders forwards and imwards, or the
head downwards. .

44, WM. sternocleuomastoideus (Fig. 68 sc).

Dugés, scapulo-mastoidien, n. 65.— Cuvier, sterno-mastoidien.— Zenker,
protractor scapulae, Pl. I, Fig. 5, 1.

A narrow muscle placed in front of and externally to the pre-
ceding muscle ; its general direction resembles that of the m. levator
ang. scap.

The fibres arise from the most. external part of the prootic and
from the hindermost part of the squamosal, under cover of the
-m. digastricus maxillae, and from the hinder portion of the cartila-
ginous tympanic ring. Covered by these muscles, it passes
backwards and downwards to be inserted into the concavity of
the anterior border of the scapula; externally to the origin of
the deltoid. .

The action of this muscle is to draw the shoulder forwards
and towards the middle line, or to bend the head downwards,

45. M. protrahens scapulae (Fig. 68 ps).
Dugés, Zenker, protractor acromii, Pl. I, Fig. 5, 3.
This muscle lies to the outer side of the rectus capitis inferior :
. . ‘ :
it arises from the prootic, and runs backwards and outwards upon the

levator anguli scapulae, to be inserted into the scapula.
It pulls the scapula forwards,

—_———_; or

_ levator scapulae, from

MUSCLES OF THE ANTERIOR EXTREMITY. 77

(b) Muscles which arise from the vertebrae.

46. M. transverso-scapularis major (Ecker), (Fig. 68 ¢s).

Dugés, transverso-interscapulaire, n. 63.—Cuvier, l. ¢., p. 380, probably
regarded as a portion of the serratus.—Zenker, Pl. I, Fig. 5, 3;

depressor acromit, Pl. IT, Fig. 3, 15.—Klein, depressor scapulae.
This muscle arises by tendon from the cartilage of the transverse
process of the fourth vertebra and by a slip from the cartilage
of the transverse process of the third vertebra. Diminishing in
size, the muscle passes outwards, forwards, and upwards to be
inserted into the posterior border of the scapula, opposite the in-
sertion of the m. sternocleidomastoideus. It draws the shoulder

inwards, backwards, and downwards.

47. M. transverso-scapularis minor (Ecker), (Fig. 68 ts’).

Dugés, transverso-adscapulaire, n. 61.—Cuvier, regarded as part of the
serratus.—Zenker, Pl. I, Fig. 5, 7, detractor scapulae.

This is much shorter than the muscle just described; it arises
under cover of the m.

the transverse process
of the third vertebra
in front of the ¢rans-
verso-scapularis major ;
and runs outwards and
forwards to beinserted
into the ventral surface
of the cartilage of the
scapula, The action of
the muscle is to draw
the shoulder inwards,
backwards, and out-
wards. Duges re-
gards this muscle as

a portion of the serra-

; Muscles of the shoulder, from below ; the sternum has been eut
tus anticus magnus, the sabi dat is Gaba coat,

remainder of which

: : d Deltoideus.
he considers is to be . és Interscapularis.

. > it Intertransversarii.
found in the jportio | ta Let. sukilicienbiiin:
scapularis of the m. A tot
obliquus externus (xi- ss Subscapularis.

: ts Transverso-scap. major.
pho-adscapulaire, Du- * ts? ‘Transverso-ecap. minor.

ges, n, 62). ts” Transverso-scap. tertius.

78 THE MUSCLES.

48. M. transverso-scapularis tertius s. serratus (Ecker), (Fig.
68 ts”).

This is larger than the muscle just described; arising by a
broad and flat origin from the transverse processes of third and fourth
vertebrae, it runs upwards and inwards to be inserted into the
ventral surface of the cartilaginous scapula near its inner border.
In position, course, and action the muscle most nearly represents the
m. serratus anticus of human anatomy.

(II.) Muscles on the scapula, that is, arising from the scapula
and inserted into the scapula or humerus.

(a) Muscles on the deeper surface.

49. M. interscapularis
(Fig. 69 @.s.).

Dugés, interscapulaire, n. 64.

One end of this muscle is
tendinous, and is attached to
the outer extremity of the su-
prascapula ; from this the
muscle, becoming fleshy and
narrower, runs towards the
middle line to become at-
tached to the ridge on the
ventral surface of the scap-
ula, from which the m. de/-
Muscles of right shoulder and upper arm, The cora- toideus and the m. subscapularis
wie etn ii ie en Ss arise, and between. which it

passes. It approximates the

e.h. M. coraco-humeralis,

el Clavicle. scapula and suprascapula and
c.o. Coracoid. 1] h ] b

dM. deltoideus. essens the angle between
@ Clavicular portion of m, deltoideus, them

a M. infraspinatus. :

i.s. M, interscapularis. -

lia. M. levator anguli scapulae. ° °
Ld. Mi tatiedmus tome” 50. M. subscapularis (Fig.
yp’ Sternal portion of m. deltoideus. "08 3)

p" Anterior sternal portion of the m. pectoralis, / -

p’” Posterior sternal portion of the m. pectoralis, Dugés, sous-scapulo huméral,
$s Scapula, n. 72

s.r, M. sternoradialis. Paes

be.) HE erleepe eerie ‘This muscle is situated on

a ea ee ee ae eee Tl lh
‘

‘from this origin the fibres

MUSCLES OF THE ANTERIOR EXTREMITY. 79

the upper or visceral surface of
the scapula. It arises from a
bony ridge found on the upper
surface of the coracoid and of
the proc. coracoideus ef the scap-
ula. The muscle runs outwards
and is inserted, after widening,
into the imner surface of the
crista deltoidea of the humerus;
it is antagonistic to the deltoid,
and draws the raised arm back-
wards and towards the trunk.

Right shoulder, from below, arm strongly
abducted.

ef Clavicle.

co Coracoid.

d Deltoideus.

@ Clavicular portion of deltoid.
hk Humerns.

ss Subscapular muscle.

(b) Muscles on the superficial surface.

51. M. infraspinatus
(Fig. 57, between /d and
dm, Fig. 71 i).

Dugés, adscapulo-huméral, /
n. 67.

The m. infraspinatus re-
presents the m. infraspina-
tus, teres major and minor of
human anatomy. It is of
triangular form, with the
broad base directed in-
wards ; it arises from the
whole of the upper sur-
face of the suprascapula
except along the inner
border which is formed

of hyaline cartilage alone:

converge outwards to a
flat tendon which unites
with that of the m. /atis-
sinus dorsi to be inserted
into the crista deltoidea hu-
meri, by means of a thin,
triangular, tendinous ex-
pansion.

Fig. 71.

Museles of the back and shoulder.

e M. cucullaris.

dm M. depressor maxillae.

Jad Fascia dorsalis.

Jd’ Fascia dorsalis reflected. »
é - M. infraspinatus. - 6
4a M. levator anguli scapulae. > <2
ld M. latissimus dorsi.

r M. retrahens scapulae.

se M. stetnocleid

80 THE MUSCLES,

General arrangement of the muscles of the shoulder-blade.
The muscles attached to the scapula and suprascapula are :

1. Muscles of the back (m. cucullaris and m. retrahens scap.).

2. Muscles of the neck (m. omohyoideus).

3. Muscles of the abdomen (portio scapularis of the m. obliquus
externus).

4. True shoulder muscles (1. /evator anguli scapulae; m. sternoclei-
domastouleus ; m. protrahens scapulae ; mm. transverso-scapularis major,
minor, and tertius 8. serratus; m. interscapularis ; m. subscapularis ;
and the long head of the m. triceps).

From above the following are visible: m. cucul/aris, a portion of
the m. subscapularis, and the transverso-scapularis maior.

From below (after cutting through and drawing aside the two
halves of the sternum) may be seen: the omohyoideus, sternocleido-
mastoideus, levator anguli scapulae, protrahens scapulae, transverso-
scapularis minor and tertius, interscapularis and subscapularis.

B. Vewnrrat Muscres or tur Suoviper (Pecrorar
Musctes )

These arise from the sternum or shoulder-girdle and are inserted
either into the humerus or into the radio-ulnar.
52. M. pectoralis (Fig. 72).
This is placed on the ventral surface of the shoulder-girdle and
consists of the following parts :

(a) Portio sternals anterior (Ecker), (Figs. 72, 73 p’).
Dugés, clavi-huméral, n. 7o (port. clavic. du grand pectoral).

This is the anterior portion of the m. pectoralis, it arises from the
sternum proper and the epicoracoids. Broad at the origin, it be-
comes narrower as it runs outwards into a tendon attached to the
crista deltoidea humeri.

(8) Portio sternalis posterior (Ecker), (Figs. 72, 73 p”).
Dugés, sterno-huméral, n. 71 (port. sternal du grand pectoral).—Klein,
humero-sternalis.

This muscle is placed immediately behind the portio sternalis
anterior, it has a somewhat broad origin from the sternum and
xiphisternum ; the muscle runs outwards and slightly forwards to
be inserted into the groove beside the crista deltoidea humert. The
tendon of the m. sterno-radialis passes between these two portions
of the m. pectoralis.

’

lie dell) ae

o_O aT SCC
;

MUSCLES OF THE ANTERIOR EXTREMITY. 81

(y) Portio abdominalis (Figs. 72, 73 p’”).
Dugés,. abdomino-huméral, n. 69 (port. costal du grand pectoral).—
Zenker, brachio-abdominalis—Klein, humero-abdominalis.

This portion represents that part of m. pectoralis major of human

Fig. 72.

Muscles of the chest, throat, and belly of Rana esculenta.
M. coraco-humeralis.

M. deltoideus.

M. obliquus abdom. internus.

M. obliq. abdom. externus.

Scapular portion of same.

M. omohyoideus.

Port. sternalis anterior to m. pectoralis.
Port. sternalis posterior to same,

Port. abdominalis of same.

M. rectus abdominis.

"eee

SFRBVVS RR RAS

M. submaxillaris.
Hyoid origin of same.
M. sternoradialis,

333

G

ue = 4

82 THE MUSCLES.

anatomy which arises from the costal cartilages, and more par-
ticularly that part which is connected with the aponeurosis of the
m. obliquus abdominis externus. The muscle arises (1) from the
m, rectus abdominis (Fig. 72 7), that is, it forms a direct continua-
tion of the outer portion of this male (2) the inner, smaller part

arises from the superficial surface of the aponeurosis of the m. ob/i-
quus abdominis. 'The muscle becomes narrower as it courses out-
wards and forwards, the outer fibres being longer and more oblique
than the inner. The action of this muscle will necessarily vary
according to the part or parts which are brought into action;
speaking generally, the anterior extremities will be drawn down-
wards and towards each other.

53. I. coraco-humeralis (Duges), (Figs. 72, 73 ¢.h.).
Dugés, n. 72.—Klein, adductor humeri.

A long, narrow muscle, lying upon the posterior border of the
coracoid and the lowest part of the m. subscapularis. By its posi-
_ tion it corresponds most nearly with the m. pectoralis minor, although
its insertion does not. It has a narrow origin from the coracoid
near the sternum, whence it courses outwards, under cover of the
port. sternalis anterior and posterior of the m. pectoralis, to be inserted
into the middle of the humerus between the deltoid and internal —
head of the triceps. It draws the limb towards the trunk.

54. IM. sternoradialis (Cuvier), (Figs. 72, 73 8.7.).
Dugés, pré-sterno-clavi-radial, n. 74.

This muscle evidently represents the biceps of man, it lies in
front of the portio sternalis anterior of the m. pectoralis, its hinder
border being under cover of the latter muscle. It takes origin from
the episternum, omosternum, and the epicoracoid ; from this broad
origin the fibres converge while coursing backwards and outwards to
be attached to a strong tendon. This tendon plays in a groove along
the crista deltoidea, and is held in position by tendinous bands
arising from the insertion of the m. pectoratlis; it then pierces the
lower portion of the muscular belly of the deltoid, and is inserted
into the anterior extremity of the radial side of the radio-ulnar.
The muscle is a powerful flexor of the forearm.

55. WM. deltoideus (Figs. 70, 72, 73 d).
Dugés, pré-sterno-scapulo-huméral, n. 68.
It is placed in front of and ‘external to the m. sternoradialis, and
represents both the m. deltoideus and supraspinatus of man. The
muscle has two points of origin :—

——— << CCU

MUSCLES OF THE ANTERIOR EXTREMITY. 83

(a) Portio scapularis, the
larger, external portion -is
attached to the outer end of
the clavicle, and to the ante-
rior process of the precoracoid,
but it arises chiefly from the
dorsal surface of the scapula
(from the same ridge as the
m. subscapularis), and lastly
from the anterior border and
ventral surface of the scapula.
The fibres pass outwards over
the shoulder-joint.

(b) Pars clavicularis (muse.

Muscle of right shoulder and upper arm. Thecora- ¢]¢j)]/9-jumeralis i arises
coids (co) and the clavicles (cl) have beer drawn 5 Klein)

Fig. 73-

asunder after cutting through the sternum. from the inner extremity of
ee ae the clavicle and from the omo-
ae nee ‘ sternum and joins the jortio
ee elie A, scapularis.

= plese crim iacs ae The muscle is inserted into
Sige 2s pepe ae the humerus, the under part
i.d. M. latissimus dorsi. of the portio scapularis being

yp” Anterior sternal portion of the m. pectoralis, attached to the upper portion
ve A igi ag ae aaa m. pectoraliss of the crista deltoidea; the
s.r. M. sternoradialis. outer fibres of this part, to-
rai : gether with those of the pars
clavicularis, are attached to the extremity of the crista deltoidea and
to the inner surface of the humerus as far as the distal extremity ;
just before its insertion the muscle is pierced by the tendon of the
m. sternoradialis. 'The deltoid draws the limb forwards.

Il. Muscies or THE ForeE-Lipk.

A. Muoscres or tHe Arm.
M. sternoradialis (hiceps). See page 82.
56. WM. triceps brachii (Fig. 73 ¢.r.).
Dugés, scapulo-huméro-olecranien, n. 75.—Capes, Zenker, m. anconaeus.
This muscle les on the upper or dorsal surface of the arm, and
has relations similar to those of the corresponding muscle in man.
The long head arises from the posterior border of the scapula at the
upper border of the glenoid cavity, and is here attached to the capsule
of the joint; the inner head arises from the upper and inner surfaces
G2

84 THE MUSCLES.

of the anterior half of the humerus as far as the extremity ; the
outer head arises from the outer surface of the humerus. Additional
fibres, which may be regarded as a fourth origin (m. subanconaeus),
arise from the upper surface of the hinder half of the humerus.
The fibres from these several origins unite to form a strong muscle,
which covers the upper, inner, and outer surfaces of the bone, and
then passes into a tendon. This tendon is attached to the capsule
of the elbow-joint and inserted into the proximal extremity of the
radio-ulnar. A cartilage, representing the olecranon, is found in the
capsule at the point of attachment of the tendon.

B. Muscxes or tHE Fore Arm.
(I.) Muscles of the flexor surface.

The muscles of this surface are arranged in two groups, so as to
form, at the elbow-joint, a triangular depression (p/ica cubiti), into
which the tendon of the m. sternoradialis sinks.

A. Muscles of the Inner Group.

Fig. 74. 57. M. flexor carpi I s. radialis (Fig.
Gq > 74 Fe).
Dugés, sous-huméro-carpien, n. 83.

This represents either the flewor carpt
radialis longior or radialis brevior of man ; it
has a broad origin from the inner border of
the humerus above the epicondylus medialis.
It becomes narrower as it passes downwards
to be inserted by a tendon into the os
semilunare and naviculare. The muscle is
much stronger in males than in females, °
and the crest from which it takes origin is
correspondingly larger in the former sex

_(p. 42). Tendinous fibres connect it with
the following muscles :-—

Muscles of the right arm of : me “
Glas eseadeste: 58. M. flewor carpi II s. ulnaris (Fig.

ed M. extens. digitorum com- 74 Fe’).
munis,

ei M.abductor digiti II longus. Dugés, epitrochlo-carpien, n. 84.

Fa’ M, flexor antibrachii later- : .
sts supoeficiilin This muscle represents the flexor carpe

Fe M. flexor carpi radial. ulnaris or ulnaris anterior, and is close to

Fc’ M. flexor carpi ulnar, : . : :
Fa M. flexor digitorum com. the inner side of the foregoing. It arises

munis. . ee XN .
Tan aa a Shey. from the eprcondylus medialis, being con-
radialis, nected by fibres with the flewor digitorum

communis, and is inserted into the 0s xaviculare.

_ of the humerus, the other deeper from the

ae ie ee a ee CLC cree,

MUSCLES OF THE ANTERIOR EXTREMITY. 85

59. MW. flexor digitorum communis (Figs. 75, 76, 77 Fa).
Dugés, epitrochlo-sous-phalangettien, n. 118.

This muscle lies most internally, and corresponds to the m. flexor
digitorum sublimis of man. It arises in common with the foregoing
muscle from the epicondylus medialis, and runs downwards to the
palm of the hand. At its entrance into this it diminishes and
passes into the flat aponeurosis palmaris. (See hand, B.)

60. MM. flexor antibrachii medialis (Ecker), (Fig. 75 Fa).

Dugés, epitrochlo-sous-radial, n. 79. (Frequently described as the pro-
nator rotundus, a description which cannot be retained, as the implied
movement does not occur in the frog.—Ecker.)

This muscle lies deeply on the inner side of the forearm, covered
by the flexores carpi; it arises tendinously from the epicondylus me-
dialis and is inserted into the inner surface of the radial side of the
radio-ulnar as far as the inferior articular extremity.

61. M. flexor antibrachii lateralis su- Fig. 75-
perficialis (Ecker), (Figs. 74, 75 Fa’).
Dugés, premier ex-huméro-radial, n. 76.

(Usually described as supinator longus,

this, for reasons similar to those in the

case of m. flexor antibrachii medialis,
cannot be retained.)

The situation of this muscle corresponds
with that of the supinator longus of man ;
it lies to the outer side of the tendon of
the m. sternoradialis, and arises by two

heads, the one, above from the outer edge

epicondylus lateralis. They unite and pass
into a tendon which, running over the
lower articular extremity of the radio-

ulnar, is partly attached to the carpus and i ee nen

partly connected with the tendon of the ca Extensor digit. communis.
m. extensor digiti IT proprius longus. From fw Flos sutinachii lee caper
its position and insertion, this muscle Pa onc a ae
evidently flexes the forearm and extends fe Flexor carpi radialis.

Fe’ Flexor carpi ulnaris.
the hand. Fd Flexor digitorum communis.

62. M. flexor antibrachii lateralis profundus (Ecker), (Fig.75 Fa’).

Dugés, epicondylo-sus-radial, n. 78.—Klein, fleror antibrachii. (Su-
pinat. brevis autt.)

This muscle arises under cover of the foregoing, from the epicon-
dylus lateralis of the outer surface of the humerus, it becomes

86 THE MUSCLES.

broader and is inserted into the whole length of the lower (volar)
ridge of the radio-ulnar. It is a powerful flexor of the forearm.

(II.) Muscles of the extensor surface.

63. M. extensor digitorum communis longus (Fig. 75 ed).
Dugés, huméro-sus-digital, n. 95.

This muscle lies on the outer border of the forearm ; it arises in
common with the short head of the flexor antibr. lateralis superfici-
alis from the epicondylus lateralis, and from the surface above it ;
it runs downwards along the outer side of the forearm, in order to
pass into an aponeurosis on the back of the hand, which expands
upon the third, fourth, and fifth fingers, and ends between them in
a free concave border. This aponeurotic expansion is connected
with the tendons of the extensor brevis digitorum.

63*. M. abductor digiti II (i, e. pollicis) longus (Fig. 74 ei).
*Dugés, cubito-métacarpien, n. 87.

This muscle lies between the foregoing and the flexor antibrachw
lateralis superficialis, and appears superficially in the interval between
Fig. 76. them. I¢ arises from the lateral surface of the
a radio-ulnar, and. runs obliquely over the m. flexor

antibrachi lateralis profundus and the hinder |
extremity of the radio-ulnar towards the second
finger into the metacarpal bones of which it is

inserted.

64. MW. extensor carpi ulnaris s. ulnaris post.
(Fig. 76 ec).
Dugés, epicondylo-sous-carpien, n. 85.—Klein,
abductor carpi internus.

This muscle has a somewhat narrow origin
from the epicondylus lateralis ; during its course
through the forearm, where it lies between the
mm. anconaci on the one side and the extensor
digitorum communi on the other, it becomes

Muscles of forearm of broader and is inserted into the outer surface of
Rana esculenta, dorsal

Sica the carpus in the following manner. By one
aa M.anconeei. tendinous slip it is attached to the palmar
» piste border of the os pyramidale, by a second slip

¥d M. flex. digit. to the outer border of the os capitato-hamatum.

This latter slip is usually connected in its dorsal portion with the
extensor digitcrum communis brevis.

MUSCLES OF THE ANTERIOR EXTREMITY. 87

65, 66. WM. anconaei s. extensores antibrachii (Fig. 76 aa).
Dugés, epicondylo-cubital and epitrochlo-cubital, n. 80, 81.

Both these muscles lie on the extensor side of the forearm ; they
spring, the one from the epicondylus lateralis, the other from the
epicondylus medialis; converging, they run downwards, enclose the
olecranon, and are inserted into the upper (dorsal) border of the
ulna, each forming a penniform muscle. They are extensors of the
forearm and assist the m. triceps. *

C. Muscres or trae Hanp.
(I.) Muscles on the palmar surface.

(1) Muscles common to all the digits.

67. M. flexor digitorum communis and m. palmaris brevis (Fig.
77 £4, ph).

The origin and course of this muscle has been described above.
At its entrance into the palm it suddenly diminishes in size and
passes into a triangular aponeurosis, aponeurosis palmaris. Into the
outer border of this aponeurosis is inserted the m. palmaris brevis
(Fig. 77 pd); this latter muscle arises from the posterior or ulnar
border of the lower extremity of the radio-ulnar below the insertion
of the mm. anconaei, and runs obliquely downwards to this insertion.

From the lower free border of the aponeurosis a number of
muscles arise which will be described with the rest of the digital
muscles,

(2) Muscles of the rudimentary thumb.

68. WM. abductor pollicis (Figs. 77, 78 ap).
Dugés, cubito-pollicien, n. 100.
This short muscle arises from the upper border of the lower
extremity of the radio-ulnar, passes transversely outwards, and is
then inserted into the anterior border of the rudimentary thumb.

69. WM. adductor pollicis (Figs. 77, 78 ad.p).
Dugés, sous-carpo-pollicien, n. ror.

This lies more superficially than the last, it arises from the
palmar surface of the os capitato-hamatum, and is inserted together
with the abductor pollicis into the thumb. Several fibres of the
extens. dig. II brevis are also imserted into the thumb. As this
member is completely covered with skin, the motions of which it
is capable are very limited. |

88 THE MUSCLES.

(3) Muscles of the second finger, which serves the purposes of a

thumb.

70. M. flexor digiti II longus s. sublimis (Fig. 77 f2).
Dugés, sous-carpo-phalangettien de lindex, n. 133.
This is a flat muscle, which arises for the most part by fleshy
fibres from the hinder free border of the aponewrosis palmaris, also

Fig. 77.

Muscles of hand of Rana esculenta, volar
surface, larger than nature.
A Aponeurosis palmaris.
abs M. abductor dig. V primus.
abs’ M, abductor dig. secundus.
ac MM. anconaei.
M. adductor pollicis,
M. abductor pollicis.
M. extensor digitorum communis.
M. extens. dig. commun. brevis.
f2 M+. flexor dig. IT longus.
M
M
M
M

F3 . flexor dig. IIT longus.
S4 . flexor dig, IV longus,
ws . flexor dig. V longus.

Sb2 . flexor dig, II brevis.

Jb3 and fb3’ MM. flexores dig. IIT breves.

Jb4 and fb4’ MM, flexores dig. IV breves.
jobs M. flexor dig. V primus,

fd M. flexor digitorum communis.

7) M. opponens,

pb Mz. palmaris brevis,

I First finger, rudimentary thumb.
Ii Second finger, functions as thumb.
Iii-V Third to fifth fingers,

Fig. 78.

Second layer of muscles on volar surface of

hand of Rana esculenta, larger than nature,

abs M. abductor dig. V primus.

abs’ M. abductor dig. V secundus.
adz M. adductor dig. IT.

ad.p M. adductor pollicis.

ap M. abductor pollicis.

ec M. extensor carpi.

fb2 M. flexor dig, II brevis.

fb2’ M. flexor dig. IT tertius.

tp MM. flexores proprii phalangum.
43
wv MM. interossei volares,

is

0 M. opponens dig. IT.

o’ M. opponens dig. V,

tt’ MM. transversi metacarpi.
I-V as in Fig. 77.

by a smaller part from the palmar surface of the os capitato-
hamatum. Tt quickly passes into a thin long tendon which is
inserted into the terminal phalanx of the thumb (second finger),

MUSCLES OF THE ANTERIOR EXTREMITY. 89

71. M. flexor digiti IT brevis s. profundus (Fig. 77 fb2).
Dugés, sous-carpo-phalangien de l’index, n. 102.
_ This flat muscle, covered by the preceding, has a tendinous origin
from the palmar surface of the 0s capitato-hamatum, together with
- one head of the flexor sublimis, and is inserted into the basal
phalanx.

72. M. fleror digiti LI tertius (Fig. 78 fb2’).
Dugés, tendini-phalangien de l’index, n. 103.
A small, thm muscle which arises close to the foregoing from the
0s capitato-hamatum, and is inserted into the basal phalanx (see
below, m. interosseus volaris I).

73. M. adductor digiti II (Fig. 78 adz).
Dugés, métacarpo-métacarpien de l’index, n. go.
This muscle represents the adductor pollicis of man; it arises from
the base of the third os metacarpal and is inserted into the metacarpal
of the second finger, which latter it draws towards the third finger.

74. M. opponens digiti IT (Figs. 77 and 78 0).
Dugés, sous-carpo-métacarpien de l’index, n. go.

This muscle represents the muscle of like name in man. It arises
from the palmar process of the 0s capitato-hamatum by a narrow
tendon and passes into a broad, flat muscle, which is inserted into
the under surface and outer border of the metacarpal of the second
finger throughout its length. It has, undoubtedly, the same action
as the corresponding muscle in man.

(4) Muscles of the third finger.
75. M. flexor digiti IIT longus s. sublimis (Fig. 77 £3).
_ The smaller portion of this muscle arises from the free border of
the aponeurosis palmaris, the chief portion, together with the flexor
brevis, from the palmar surface of the os capitato-hamatum. The

two portions pass into one long tendon, which is inserted into the
last phalanx.

76,77. MM. flexores digiti III breves s. profundi I, II (Fig.
77 fo3 and 763’).
~ Dugés, tendini-phalangiens du medius, n. 104, 105.

‘These two muscles arise in part from the free border of the 2yo-
neurosis palmaris, in part from the volar surface of the os capitato-
hamatum, and pass backwards on either side of the muscle last
described, to be inserted into the basal phalanx. Dugés regards
these as analogues of the mm. /umbricales.

90 THE MUSCLES.

78. M. flexor metacarpi dig. III.

This is a somewhat strong muscle, which arises by fleshy fibres
from the palmar surface of the 0s capitato-hamatum; and is inserted
into the palmar surface of the metacarpal bone.

(5) Muscles of the fourth finger.

79. MW. flexor digiti IV longus s. sublimis (Fig. 77 74).

It arises at the free border of the aponeurosis palmaris, and is
inserted into the terminal phalanx by a thin tendon.

80, 81. MM. flewores digiti IV breves s. profundi I, II (Fig.
77 fa and fb4’).
Dugés, tendini-phalangiens de l’annulaire, n. 108, 109.

Dugés regards these also as analogues of the m. /umbricales ; they
arise on either side of the foregoing muscle from the free border of
the aponeurosis palmaris, and are inserted by tendons into the basal
phalanx.

82. M. flewor proprius phalangum dig. IV (Fig. 78 fp).
Dugés, phalango-phalangien, n. 115.

A small muscle which arises by two slips from the palmar surface
of the basal phalanx, and is inserted into the base of the middle
phalanx.

83. WM. fleaor metacarpi dig. IV (Fig, 78 14).
This somewhat strong muscle arises from the os capitato-hamatum,
and is inserted into the palmar surface of the metacarpal bone.

(6) Muscles of the fifth finger.
84. WM. flewor dig. V longus s, sublimis (Fig. 77 £5).
This corresponds exactly with the corresponding muscle of the
fourth finger.
85. MW. flexor dig. V brevis (Fig. 77 05).

This muscle arises from the free border of the aponeurosis and
is inserted into the basal phalanx.

86. WM. flexor proprius phalangum dig. V (Fig, 78 fp).
Dugés, phalango-phalangien, n. 17.
It corresponds exactly with the corresponding muscle of the
fourth finger.
87. MM. opponens dig. V (Fig. 78 0’).
Dugés, deuxitme sous-carpo-métacarpien du digitule, n. 92.
This muscle has a narrow origin from the palmar surface of the

a

MUSCLES OF THE ANTERIOR EXTREMITY. 91

os capitato-hamatum, it widens and is inserted into the outer border
of the metacarpal of the small finger. It draws this finger towards
the thumb. /

88. WM. abductor dig. V primus (Figs. 77 and 78 ab5).
Dugés, sous-pyro-pré-métacarpien du digitule, n. 93.
This muscle arises from the palmar border and the outer surface

of the os pyramidale, and is inserted into the basal phalanx by a
thin tendon.

89. MW. abductor dig. V secundus (Figs. 77 and 78 ab5’).
Dugés, sous-pyro-post-métacarpien du digitule, n. 94.
It arises from the posterior part of the os pyramidale, is short,
and is inserted into the outer side of the metacarpal.

(II.) Muscles on the dorsal surface.
NM. extensor digitorum communis longus (Figs. 75 ed and 77 ee).

90. WM. extensor digitorum communis brevis (Fig. 79 €3, €4, €5)-
Dugés, sous-pyro-phalangettien du ITI, IV, V, n. 124, 128, 131.

Covered by the foregoing, this muscle arises from the os pyra-
midale ™m conjunction with the extensor pollicis and from the os
capitato-hamatum, The part destined for the third finger, together
with that for the fourth, arises from the os pyramidale, passes
obliquely backwards into a tendon which runs along the inner side
of the corresponding finger to be inserted into the last phalanx.
That for the fifth finger arises from the inner projection of os
capitato-hamatum being: here attached to the insertion of the m. ex-
tensor carpi ulnaris, and is inserted in a similar manner into the
terminal phalanx of the fifth finger.

91. WM. abductor digiti II (i.¢. pollicis) longus (Figs. 74 ei and
79 ab.2).

For the origin and course of this muscle in the forearm see
No. 63. The muscle passes obliquely over the wrist-joint from
the little finger towards the inner side and from before backwards,
it is inserted into the metacarpal of the second finger (thumb).
The place of insertion of this muscle into the metacarpal (compare
p- 47) is, in the males, developed into a ridge and process, the
muscle itself is enlarged during the breeding season. This muscle
abducts the thumb and by this means aa! upon the chest of the
female when clinging to her.

92 THE MUSCLES,
92. WW. extensor digiti IT proprius longus (Fig. 79 2, 2’).
Dugés, cubito-radio-sous-phalangien de l’index, n. 96.
This muscle lies obliquely on the back of the hand, parallel
Fig. 79. with the m. abductor digiti II. Tt
arises by two heads, one from the
tendon of the flexor antibr. lat.
superf. (n. 60) upon the hinder ex-
tremity of the radio-ulnar. This
tendon conceals the hinder end of
this bone by means of a patella-like
thickening, and sends forth three _
tendinous prolongations; of these,
the one is attached to the ulnar
border of the radio-ulnar, the second
to the os naviculare, while the third
constitutes that portion of the m.
extens. dig. II proprius long. which
is under consideration. The second

eb2
Muscles of hand of Rana esculenta.
view, twice natural size.

Dorsal

ab.2. M. abductor dig. II longus,
ab.2' M. abductor dig. II brevis,
adz M. adductor dig. IT.

a" } M. extensor dig. II longus.
2

head arises from the os pyramidale
in connection with the extensor digi-
dorum communis brevis (n. go). The
heads unite to form a long muscle,

‘i \.M. extensor digitorum communis
4 j brevis.

which runs obliquely towards the
second finger, passes into a tendon,
which, after forming’ connections
by some musctlar fibres with the
metacarpal, is inserted into the ter-
minal phalanx.

eb2 M. extensor dig. II proprius
brevis.

ec M. extensor carpi ulnaris.

fa M. flexor antibr. lat. superficial.

#3

4 hana, interossei,

t's

TI-V as in Fig. 77.

. 93. MW. extensor dig. LI proprius brevis (Fig. 79 eb2).

Dugés, sus-luno-phalangettien de l’index, n. 120.

This muscle -lies between the preceding muscle and the abductor
dig. II longus. It arises from the os naviculare, and also includes
some fibres which arise from the second metacarpal. The tendon
runs along the radial side and is imserted along with the last
muscle into the terminal phalanx.

94. M. abductor dig. II brevis (Fig. 79 ab.2’).
Dugés, sus-luno-métacarpien de l’index, n. 88.
This represents the abduct. pollic. brevis of man, lies on the outer
side of the hand, arises from the os naviculare, and is inserted into
the second metacarpal.

OR
;

—oc—=——_- °°}

MUSCLES OF THE ANTERIOR EXTREMITY. 93

95. M, extensor dig. III proprius.
Dugés, sus-luno-phalangettien du médius, n. 122.

This muscle has two heads of origin, from the os naviculare and
lunatum. ‘These form one muscular belly, which rapidly diminishes
and passes into a tendon; this, after receiving a few muscular
fibres from the second metacarpal, runs to the outer part of the
dorsal surface of this finger as far as the terminal phalanx, where it
is inserted.

96. WM. extensor dig. IV proprius.
Dugés, sus-pyro-phalangettien de l’annulaire, n. 128.

By a somewhat broad base, this muscle arises from the os navi-
culare and lunatum. The tendon receives fibres from the fourth
metacarpal and runs on the outer half of the dorsal surface of this
finger as far as the middle phalanx, where it is inserted.

(IIL.) MM. interossei.
97, 98. [a.| IM. transversi metacarpi (Ecker), (Fig. 78 4, ¢’, adz).
These lie transversely between the metacarpals. There are three ;
the first has been already described as m. adductor digiti II (n. 73) ;

the second is stretched between the third and fourth metacarpals,
and the third between those of the fourth and fifth fingers.

99,100, 101. [b.] ILM. interossei volares.

One may regard as such, four long, thin muscles, which take
origin near one another on the palmar surface of the carpal bones,
and diverge from this towards the second and fifth fingers.

1. The first of these muscles (Fig. 78 72’) has already been
described above as the m. flexor digiti LI tertius (n. 72).

2. The second (Fig. 78 13) passes from the origin already de-
scribed to the palmar surface of the basal phalanx of the third
finger.

3. The third (Fig. 78 74) runs, in like manner, to the fourth
finger.

4. The fifth (Fig. 78 75) to the fifth finger '.

102 to 108. WM. interossei dorsales.
These arise in common from the metacarpals, and are inserted

' into the bas4l phalanx of the corresponding surface on the finger.

* Whether these muscles may be regarded as mm. interossei is open to discussion,
as they appear to act more as mm. opponentes.

94 THE MUSCLES.

1. ‘The ¢hird finger has two, one to the radial side (Fig. 79 7 '3),
one to the ulnar side.

2. The fourth finger has three, the third (Fig. 79 74) arises from
the carpus, and perhaps ought rather to be regarded as an extensor.

3. The fifth finger has two. |

IV. MUSCLES OF THE HINDER LIMB.

J. Muscres or tHe THIGH.

General arrangement (Figs. 80, 81).

a. The m. triceps femoris forms the outer border of the ines and
extends on to both the dorsal and ventral surfaces. The outer
border therefore corresponds with the anterior surface of the thigh
of man, in consequence of the thigh in the frog being normally
rotated outwards.

b. The m. vastus internus (v.i.) and a portion of the adductor longus
(ad’), the sartorius (s), a portion of the adductor magnus (ad’”’), and
the rectus internus major (r.i’) are found on the inner surface of the
thigh.

e. The rectus internus minor (r.<’) forms the inner border.

d. On the dorsal surface are to be seen, nearest the trunk, the
glutacus (gZ), on the outer border the vastus externus (v.e.), the pyri-
_ formis and biceps (p and b), then the semimembranosus (sm), and lastly
the rectus internus minor (77).

e. By reflecting the rectus internus major (compare Fig. $2) there
are exposed to view: the semitendinosus (st), the whole length of
the adductor longus, magnus (ad’ and ad”), and brevis (ad”). By re-
flecting the triceps, one sees (Figs. 84, 85) the 2io psoas (ip), and
beneath the semimembranosus, the quadratus (qf), and capsularis
Semoris (09).

Description of the separate Muscles.

(A.) Muscles of the dorsal surface.
109. MW. glutaeus (Fig. 80 g/).
Dugés, ex-ilio-trochantérien.—Zenker, glutaeus maior.

The tendinous origin of this muscle is found on the outer surface
and upper border of the two hinder thirds of the iliac bone. Thence
it runs outwards and backwards between the head of the m. vastus
eaternus (ve) on the one side, and the i/io-psoas and rectus anticus (ra)

= num or the vastus externus(v.e.),

:
E.
3

_ tendon into the tibio fibula. ~

dangum or the rectus femoris
rl =

MUSCLES OF THE HINDER LIMB.

on the other, to be inserted
into a tubercle (trochanter)
of the femur.

110. HM. Pyriformis (Fig.
80 7).

Cuvier, pyramidal. Dugés, -, Oo
coccy-fémoral, n. 136. + tr,

A narrow, slender muscle,
arising from the apex of the
coccyx; it passes obliquely
outwards and backwards to
the thigh, to be inserted deep-
ly between the m. vastus exter-
nus and the diceps, into the in-
ner surface of the femur, but
towards the ventral surface.

MM. triceps femoris s. exten-
sor eruris communis (Fig. 80).
Dugés, pelvi-fémoro-rotulien,

n. 145, 146, 147.

This is a large, strong
muscle, having three—heads
of origin, and inserted by a,

‘The three heads are the caput
anticus (r.a.), the caput exter-
and the caput internum or the

vastus internus (Fig. 82 vi); of 2
these, the first. is situated

' on the outer border of the

95

thigh, the second on the dor- Muscles of left thigh of Rana esculenia. Dorsal view.

‘sal surface, and the third on Diem
the ventral surface. a, aM. aga
11. [a.] W rectus femoris 2 pyriformis~
_ anticus (Figs. 80, 82 ra). 7. Me Xectus anterior,
(ventral) surface of the iliac __ cat ee eaten
bone about its middle and — — ~<. Mt: vastus externnsa_—

beneath the m. glutaeus. The muscular belly quickly passes into

y

ay

_

96 THE MUSCLES.

an aponeurosis, which covers the other two muscular masses and
combines with their tendons.

112. [b.| I. vastus externus (Fig. 80 v.e.).
It arises from the upper and hinder extremity of the iliac bone
(Fig. 42 i’) behind the g/utaeus, which here sinks in between this
muscle and the rectus anterior. ;

113. [c.] I. vastus internus (Figs. 81, 82 vi).

It arises from the whole of the under and outer surfaces of the
hip-joint capsule, and from tendinous slips which pass from this
- capsule downwards on the under surface of the muscle, (from the
pubis and the femur I have not seen any fibres of origin, as stated
by others). Anteriorly the vastus may easily be separated into two
heads. The two vastz unite and form one muscular belly, in the
formation of which, as above stated, the rectus anticus takes no
part. This united muscle passes into a tendon which, without the
mediation of a patella, passes over the knee-joint to be inserted into
the anterior extremity of the tibio-fibula, and is prolonged into the
fascia of the leg. .

/
114. MW. ilio-fibularis s. biceps (Fig. 80 3).
Dugés, ilio-péronien, n. 149.—Zenker, flexor externus tibiae, p. 42.

This is a long, somewhat narrow muscle, which lies to the inner
side of, and partly covered by, the vastus eaternus, between which
and the semimembranous it is placed. Itarises by a tendon between
‘the t/io-psoas and pyriformis from the ilium above the acetabulum
and behind the origin of the vastus externus. From here it passes
backwards, separated from the vastus externus by a strong ligam.
intermusculare. On the inner side of this muscle, between it and
the m. semimembranosus, run the vessels of the thigh and the J.
ischiadicus. The muscle then divides into two portions, of which
one is inserted high up on the inner and under surface of the
femur. This is probably the muscle which Klein (¢. ¢., p. 61)
describes as the extensor brevis. The other long muscular belly
passes into a thin tendon, opposite the hinder extremity of the
thigh, it divides into two portions; the anterior is inserted into
the dorsal surface of the hinder extremity of the femur, the other
into the dorsal surface of the tibio-fibula. Between the two is

stretched an arch with the concavity outwards. ‘This insertion of ~

the biceps is covered by the stronger tendon of origin of the m. gas-
trocnemius (compare Fig. 87).

,

MUSCLES OF THE HIND LIMB. 97

115. M. semimembranosus (Figs. 80, 86 sm).

Dugés, sus-ischio-poplit¢é, n. 148.—Klein, p. 60, extensor femoris
sublimis.

This muscle lies on the dorsal surface of the thigh, to the inner
side of the biceps and pyriformis : it is a broad muscle, which takes a
tendinous origin from the hinder and upper angle of the symphysis
ossis i/ei, and:is inserted by a flat tendon into the dorsal surface
of the ligaments of the knee-joint, and through these into the
tibio-fibula. The tendon is formed rather abruptly from the muscle,
and is surrounded (Fig. 86) by the concave arch, which forms
the tendon of origin of the gastrocnemius (q.v.). A little behind
its middle (compare Fig. 81) the muscle is divided obliquely into an
anterior and a posterior portion by an aponeurotic septum. As
all the fibres are interrupted by this structure, the muscle may
very easily be torn through.

(B.) Muscles on the ventral surface.
:16. 1. sartorius (Figs. 81, 82 *).

Dugés, sous-iléo-tibial, n. 150.—Klein, gracilis.

This long, flat muscle lies along the middle of the ventral surface
of the thigh ; it arises by a tendon from the anterior inferior angle
formed by the symphysis of the mnominate bones, and ter-
minates m a tendon behind the knee-joint, forming a kind of

pes anserinus 11 the fascia of the leg, similar to that of the semi-
tendinosus *,

117. M. rectus internus major (Ecker), (Figs. 81 7.2’, 82 ri’).

Dugés, post-ischio-tibial profond, n. 152.—Klein, semimembranosus.
This is a broad and flat muscle, thinned out at either extremity ;
it occupies the inner half of the ventral surface of the thigh, and is
in relation with the adductor magnus externally and anteriorly, with
the sartorius posteriorly, and the rectus minor muscle internally.
The muscle arises by a tendon from the pubic symphysis;
it covers in its course the semitendinosus, then passes into a
strong tendon, which blends with the tendon of the rectus
minor, to be inserted by a slip into a process of the tibio-fibula
representing the fuerositas tiliae, first passing between the ten-
dons of the sartorius and semimembranosus, which here form an
aponeurotic arch; a second slip passes under the tendon of the

* The sartorius has lately been used by Kihne in his researches on the nerve-
endings in muscle and on muscle contraction without nerve supply (du Bois-Rey-
mond’s and Reichert’s Archiv, 1859. Page 314).

i a —

a)

THE MUSCLES.

Vi.

ese

Muscles of left thigh of Rana esculenta. Ventral surface.

ad’ M.
ad”. M.
ad!” M.
«CG. MM.
ft. M,

~ gc. M,

ri’ M.
rt’ M,
8 M.
tia. M.
tee MM,
v¢. M,

adductor longus, .
adductor brevis.
adductor magnus.
extensor cruris,
flexor tarsi.
gastrocnemius.
rectus internus majo:
rectus internus mino:
sartorius.

tibialis anticus.
tibialis posticus.
vastus internus, —

oY
as

t.ayil tus

&

m. semitendinosus to
be inserted into the
upper surface of the
tibio-fibula, under it
passes the N. ¢ibialis.
A third thread - like
tendon passes to the
m. semimembranosus,
Somewhat behind its
middle (Fig. 82) the
muscle is traversed by
an inscriptio tendinea,
by which the whole of
the fibres are inter-.
rupted.

118. UM. rectus in-
ternus minor (Ecker),
(Figs. 80, 81 7.7”).

Dugés, post-ischio-tibial
superficiel, n. 151.—
Zenker, fleror tibiae

# magnus.—Klein, is-
__ ehio-tibialis,
Situated entirely on
the inner ‘surface of
the thigh, this narrow
muscle arises by a
tendinous band which
runs the whole length
of the pubic symphy-
sis, and is connected
posteriorly with the
sphincter ani, anterior-
ly with the rectus
abdominis ; posteriorly —
it passes into a thin
tendon which is also
connected with the
muscle just described
(117). In its course

_internus (Fig. 81 ad’). The muscle

MUSCLES OF THE HIND LIMB. 99
this muscle is ftached to the skin by strands of vessels and con-

vastu i ternus major and minor together undoubtedly
mith rectus internus or gracilis of human anatomy.

The ternus major is, however, regarded as corresponding
with the adductor magnus by Dugés, and with the semimembra-

nosus by Klein; by considering the position and attachments of
these muscles one must arrive at a different conclusion.

MAM. adductores femoris.

119. [a] MW. adductor longus (Fig. Fig. 82.
82 ad’).
Dugés, sous-ilio-fémoral, n. 141.
Without further dissection this
muscle is only partially visible be-
‘tween the m. sartorius and rastus

is flat and long, and arises by a
tendon from the anterior inferior
angle of the pubie symphysis (Fig.
42 #), partially covered by the
origin of the sarterius. Thence the
muscle passes between the vastus
internus and the adductor maguus,
and finally is inserted below the
middle of the femur, together with
the latter muscle.

120. [b] ¥. adductor magnus ~

(Figs. 81, 82 ad”).

_ Dugés, sous-ischio-pubi-fémoral (ad-
ductor 1 and 2), n. 142, 143.—
Hein, adductor magnus and ex-

tensor femoris profundus. Ventral surface.
This muscle is visible between the ae Me oeteten kenge.

- sartorius and rectus internus major gf Ms

in the anterior half of the thigh, ere Ne set tt ett

posteriorly it is covered by these pe ae

muscles. It arises by a tendon | * ¥.=mitendinosux

from (a) the pubic symphysis and =”

ischii, and is in this position divided into two portions, between
H2 -

100 THE MUSCLES.

which passes the tendon of one head of the m. semitendinosus (Fig.
83 st”); (4) a second part arises from this same tendon (Fig. 83 s¢’”)
and joins with the first part. Thus formed the muscle passes to be
inserted into the distal half of the inner surface of the femur as
far as the condyle. Near its hinder extremity, however, it passes
on to the dorsal and outer surfaces, and thus forms a kind of
muscular sheath surrounding the distal portion of the bone.

121. [ce] IM. adductor brevis (Figs. 81, 83 ad”),
and
122, [d] M. pectineus (Fig. 83 pe).
Dugés, sous-pubio-fémoral (analogue of the pectineus, pee of the
add. brevis also).

These two small muscles which lie under cover of the sartorius, adduc-
tor longus and magnus,
appear externally as one
muscle, but may easily be
separated (Fig. 83). They
arise close together from
the pubic symphysis, and
are inserted into the
inner surface of the an-
terior half of the femur.
They are not attached to
the adductor magnus.

Fig. 83.

123. I. semitendinosus

(Fig. 83 st, st’, st”).
Dugés, bis - ischio - tibial,
n. 153.— Zenker, Ji-

ceps.

This is a long thin mus-
AD \\\ cle, only visible after re-
vi" moval of the m. rectus

Deep muscles of left thigh of Rana esculenta.

ad’ M. adductor longus. ®,.. -.<. Av».
+ ad” M, adductor brevis.
ad” M. adductor magnus,

«ip M. ilio-psoas.
» pe M. pectineus.

ra M. rectus anticus,

vi’ M. rectus internus maior

ri’ M. rectus internus minor = efigastan.
s M. sartorius.

st Belly of m. semitendinosus.

st’ M, semitendinosus (cap. posticum).

st” M. semitendinosus (cap, anticum).

st” Fibres passing into the adductor magnus.
vi M. vastus‘internus,

internus, by which it is en-
tirely covered. It arises
by two long thin tendons,
one (caput posticum, st’)
from the pubic symphysis,
the other (caput anticum,
st”) from the hollow be-
tween the symphysis and
the acetabulum. Thelatter

~~

MUSCLES OF THE HIND LIMB. 101

-

passes through a slit in the adductor magnus, and so affords this
muscle another point of origin; then backwards between the
adductor magnus and the rectus internus major and under the lower
third of the thigh, and unites with the posterior head of origin. The
muscle so formed passes into a thin tendon, and, together with that
of the sarforius, forms an aponeurotic arch, connected with the fascia
of the leg, under which the tendons of the rectus internus major and

minor pass.

(C.) Deep muscles of the thigh.
To these, in addition to the adductor brevis, pectineus, and the
portion of the diceps already described, belong also the following :

124. W. ilio-psoas (Figs. 82, 83, 84 ip).
Dugés, intra-ilio-fémoral (=iliacus and psoas)——Cuvier, Zenker,
Klein, iliacus internus.
_ The fibres of this muscle take a broad origin from the pelvic
surface of the ilium, pass outwards over the lower margin of the

Fig. 84.

Fig. 85.

bone and form a flat muscle with its apex. pointed posteriorly. It
erossés the hip-joint between the m. rectus and vastus internus,

102 THE MUSCLES,

covering the hinder part of the m. g/utaeus, and is inserted into the
outer surface of the middle third of the femur.

125. M. quadratus femoris (Fig. 84 qf ).

Dugés, post-ilio-fémoral (Homologue of the glutaeus marinus), n.197.—
Zenker, glutweus minor, p. 42.

This muscle is of a somewhat elongated, triangular shape, and
arises, under cover of the pyriformis, from the ilium behind the ace-
tabulum ; it passes backwards over the joint to-be inserted into the
inner and under surfaces of the femur, between the pyriformis and
ilio-psoas ; below, it is in direct relation with the adductor brevis.

126. M. obturatorius (Figs. 84, 85 0g).
Dugés, ischio-pubi-fémoral, n. 139 (?).—Zenker, m. capsularis femoris.
This small muscle is deeply situated upon the hip-joint, and
covered by all the other muscles that arise from the symphysis. Its
origin from the innominate bone extends from the superior posterior
angle of the symph. ossis ilii to about the middle of the pubic sym-
physis ; the muscle fills the space between the crest of the sym-
physis and the acetabulum. The fibres converge to pass into a
strong tendon, which is inserted into the posterior and anterior
surfaces of the head of the femur. The muscle appears to represent
collectively the small rotators of human anatomy, m. obturator ex-
ternus and internus and the gemelli.

II. Muscres or tHe Lue.
General description.

On the outer surface (the anterior of man), covered by the fascza
cruris, into which the tendon of the eatensor communis cruris or
triceps is prolonged, are found the following muscles : nearest to the
Wone, the m. extensor cruris brevis ( Mc externally, the m. tibialis
anticus (ta) and the m. peroneus (pe). On the inner surface (the
hinder of man) lie the gastrocnemius (gc) and tibialis posticus (tp), and
deeply the flexor tarsi sup. (ft).

127. WW. gastrocnemius (Figs. 80, 81, 86).
Dugés, bi-fémoro-plantaire, n. 159.
This important muscle arises by two tendinous heads. The one
(Fig. 86 g’) rather nearer the middle line of the popliteal space, is
by far the stronger: it arises by a broad, tendinous expansion,
which covers the knee-joint, and is attached to the femur and the
tibio-fibula by anterior and posterior bands respectively ; it ends

\

MUSCLES OF THE HIND LIMB. 103

internally in a concave aponeurotic arch: the second head is a thin,
tendinous slip, arising from the common tendon of the ¢riceps as
this lies on the knee-jomt. The muscle is thickest near its origin,
and then gradually*diminishes in size as it passes backwards; the
superficial surface is convex, the deep surface is flat. By tracing the
tendons of origin, they are seen soon to unite and form a common
flat tendinous surface, broad in front,
contracted behind ; this aponeurosis
lies in a plane running” obliquely
from the deep surface towards the
superficial surface, without, how-
ever, reaching this. The muscular
_ fibres arise from both surfaces of the
aponeurosis, the fibres of the two
sides diverging slightly as they pass
backwards so as to be inclined at a
small angle to each other. The
fibres are inserted into a fibrous ex-
pansion (4y) which lies on the su-
perficial surface of the muscle; thin .
and slight in front, this aponeurosis
- rapidly thickens posteriorly until it
passes into the tendo Achillis.
128. MM. tibialis posticus (Fig.
86 ¢.p.).
Dugés, cruro-astragalien, n. 160.
Covered by the gastrocnemius this

Muscles of the right leg and foot of Rana esculenta.
Dorsal view.

_ ah, MM. abductor hallucis.

FJ. M. flexor digitorum III, IV, V longus.

FJ, Mz. flexor digitorum I and IT longus.

9g M. gastrocnemius, drawn towards the right.
g Tendon of origin of gastrocnemius.

Ze, Ligamentum calcanei-

104 HE MUSCLES.

muscle occupies the whole of the inner and upper surfaces of the
tibio-fibula, from which it arises by numerous fibres. Opposite the
hinder extremity of the bone the muscle becomes free and passes
somewhat abruptly into a tendon, which courses behind and over the
malleolus internus, on to the dorsum of the foot, and is here inserted
into the anterior extremity of the astragalus. 1 cannot agree with
Duges that this muscle corresponds with the so/ews (Ecker).

, 129. I. extensor cruris brevis (Fig. 87 ¢e).
Dugés, pré-fémoro-tibial, n. 15.4.

Covered by the strong fascia cruris, and lying between the m, f-
bialis anticus and the tibio-fibula, this muscle arises by a long tendon
from the inner condyle of the femur; it passes backwards in the
groove on the anterior extremity of the tibio-fibula, covered by the
tendon of the triceps femoris, and is then inserted by muscular
fibres into the outer surface of the tibio-fibula almost as far as the
posterior third of the bone. (Dugés regards this muscle as the
upper, 1.e. anterior, portion of the ¢cbialis anticus.)

y 180. IM. tibialis anticus (Figs. 80, 81, 87 ta).

Dugés, pré-fémoro-astragalien and pré-fémoro-caleanien, n. 156 and 157 ;
the former he regards as one part of the ¢ib. anticus, the latter
as the peroneus longus I.—Zenker, tib. ant. biceps.

The tendon of origin of this muscle is attached to the femur near
the tendon of the m. ewtensor cruris brevis, and to the joint-ligaments.
The muscle is placed under the fascia cruris, its long tendon of
origin passing’ beneath the tendon of the ¢riceps in a special sheath
through the joint ; the tendon then gains a muscular belly .which
bifurcates at about the middle of the leg, forming two muscular
masses, coursing along the outer and the inner side of the leg re-
spectively... The latter is inserted into the dorsal surface of the astra-
galus by a tendon, and the former into the dorsal surface of the
calcaneus ina similar manner. The muscle extends the foot and
flexes the tarsus ; the latter movement is very distinct on account of
the insertion of the muscle being so near the hypomochlion.

y 181. I. flexor tarsi anterior (Ecker), (Fig. 87 1).
Dugés, ex-tibio-astragalien, n. 155.—Zenker, tibialis anticus simplex,
This muscle arises where the insertion of the extensor cruris brev’
ceases, from the middle of the under surface of the tibio-fibula, and
passes backwards between the two tendons of the m. tibialis anticus
along the outer side of this muscle, to be inserted by a tendon

MUSCLES’ OF THE

into the inner side of the anterior
articular extremity of the astra-
galus and the fascia dorsalis pedis.

x 132. U. peroneus (Figs. 80 pe,
87 p).
Dugés, génio-péronéo-calcanien,
n. 158.

This is a strong muscle which is
attached by a long tendon of origin
to the hinder extremity of the
femur and the ligaments of the
knee-joint. The tendon runs in a
sheath through the joint and pos-
teriorly becomes muscular; the
muscle passes downwards on the
outer side of the tibio-fibula to be
inserted into the ma//eolus externus
of this bone and into the anterior
extremity of the calcaneus. It has
an action similar to that of the
m. tibialis anticus. ;

III. Muscrzs or rue Foor.
A. Muscteson rune PranrarSorrace.
133. Aponeurosis plantaris

(Fig. 88 A.p.).

As already mentioned, the ten-
don of the m. gastrocnemius is, at
the heel, continued into a strong
aponeurosis, and possesses at this
place a thickening '. The aponeu-
rosis is of triangular form, the
base directed towards the toes and
attached to these. The lateral
borders of this triangle are con-
tinued into weaker fasciae, which
are attached to the two long tarsal
bones. The inner border in par-
ticular gives a strong bundle of

* Lehmann, Ueber den Knorpel in der Achill
U. Zool. XTV, p. 10g. (See also literature on

HIND LIMB. 10

Muscles of leg and foot of Kana esculenta,
seen from below.

a.5.5 M. abductor dig. V longus.

ec M. extensor cruris brevis.

e.d.x M. extensor digit I longus,

¢.d.4 M. extensor digit IV longus.

e.d.5 M. extensor digit V longus,

Ft Mz. fiexor tarsi anterior.

Ft M. flexor tarsi posterior.
ig M. gastrocnemius.

pM. peroneus.

ta M. tibialis antieus.

iF M. triceps femoris.

cartilage, Sect. VIT.)

essehene des Frosches, Zeitschs. f.

A\

106 THE MUSCLES.

fibres to the astragalus, and is thus connected with the fascia of the.
dorsum of-the foot; externally this aponeurosis is attached to a
cartilage (Dugés, os sesamoide, /.¢., n. 66), situated on the plantar
surface of the joint between the calcaneus and the os metatarsi IV.

134. Ligamentum calcanei (Ecker), (Figs. 88, 89 /.c.).
If the tendo Achillis be divided and the aponeurosis plantaris
reflected towards the toes, there is
seen, arising from the posterior head
of the tibio-fibula, in. its whole
breadth, a ligament (between the
th. posticus and. peroneus). This
ligament forms a firm surface on
which the thickened portion of the
tendo Achillis may move, and which
evidently represents the tuberosity
of the heel bone. I have there-
fore named the entire structure the
ligamentum calcanet.

Several muscles arise from this
ligament, viz. :—

135. MW. extensor tarsi (Sleia)
Figs. 88, 89 ¢./.).

Dugés, tibio-sous-astragalien (regarded
by him as the homologue of the
tibialis posticus). >

Covered by the two succeeding
muscles, this muscle arises from the

Muscles of the right leg and foot of Rana esculenta.
Dorsal view.

a.h, M. abductor hallucis.

a.lx M. abductor longus digiti L.

Ap. Aponeurosis plantaris.

b M. biceps.

et. | M. extensor tarsi.

Fl. M. flexor digitorum III, IV, V longus,

FJ’. M. flexor digitorum I and IT longus.

g M. gastrocnemius, drawn towards the right.

g Tendon of origin of ppeipoonensing.

Lc, Ligamentum calcanei.

p M. plantaris.

‘ ;
vi. MM. internus maior and nifror,
s.m, M.semimembranosus.
s.t, M. semitendinosus.

t.A. Tendo Achillis.

t.A’, Thickening of tendo Achillis,
ip. M. tibialis posticus.

ve, M. vastus’externus.

tof. M, vastus internus.

MUSCLES OF THE HIND LIMB. 107

ligamentum caleanei, rans backwards, and is inserted into the whole
length of the plantar surface of the astraga/us. It extends the foot.

136. M. plantaris (Figs. 88, 89 p).
This takes its origin from the ligamentum calcanei to the inner side
and below the last muscle. It passes backwards and is inserted
into the dorsal surface of the aponeurosis plantaris.

137. M. flexor digitorum III, IV, V longus (Ecker), Figs. 88,
89 Fd).
Dugés, péronéo-sous-phalangettien ( fleror dig. longus).

This muscle also arises
from the /igamentum cal-
canei to the outer side of
the m. plantaris. It runs
backwards over the apo-
neurosis plantaris, and at
the free margin of this
passes somewhat sud-
denly into a strong ten-
don, which traverses an
aponeurotic canal, formed
by fibres of the aponeu-
rosis passing above and
below the tendon, from

Muscles of the plantar surface of foot
of Rana esculenta, twice natural
size.

A.p. Aponeurosis plantaris, divided.

ab.5s. M. abductor dig. V.

ad.5. M. adductor dig. V.

ad.l.1, M. adductor longus dig. 1.

et. M. extensor tarsi.

F.5. M. flexor brevis dig. V.

Fil, Mz. flexor digitorum III, IV, V

longus.

PI. M. flexor digitorum I, II longus.

#1.

t.2.

4.3.

1.3’. -Musceuli Iumbricales,

4", |

t.4. Tendo Achillis,,
t.A’, Thickening in tendo Achillis,
&p. M. transversus plantae poste-

rior.
tp’. M. transversus plantae anterior.

108 THE MUSCLES.

the cartilaginous enlargement in the tendon to the median border
of the aponeurosis. The tendon forms. three slips for the fifth,
fourth, and third toes: these are slightly attached to the aponeurosis,
but reach beyond its free border to be inserted into the terminal
phalanges of the toes mentioned, and are held down by fibrous
bands. (The small m. /umbricales arising from these tendons are de-
scribed below.) .

138. M. flexor digitorum I, II longus (Ecker), (Figs. 88, 89 /’/’.).

The tendons, by means of which the terminal phalanges of the

first and second toes are flexed, arise directly from the posterior
border of the aponeurosis.

139, 140. MM. transversi plantaue (Ecker), (Fig. 89 t.p., t.y’.).

The movements of the aponeurosis and through it the move-

ments of the tendons attached to it are influenced not only by

the m. gastrocnemius and plantaris, but also by two other muscles,

which together have been described as the flewor dig. longus interaus
(Klein), or as the tarso-sous-phalangettien (Dugés, 221).

a. WM. trausversus plantae posterior (t.p.).

This takes its origin from the plantar cartilage, widens as it
courses backwards and inwards to be inserted into the dorsal
surface of the aponeurosis plantaris; from this the tendons for
the first-and second toes (jleror dig. longus I and 17) arise, thus there
is no direct connection between the muscular fibres of the two
muscles,

b. WM. trausversus plantae anterior (t.p’.).

This muscle is covered by the last ; broader anteriorly, it arises
from the calcaneum, and is inserted to the inner side of the last
muscle into the dorsal surface of the aponeurosis. This muscle,
like that just described, is not continued directly into the tendon
of the flexor of the toes, they cannot therefore be regarded as
flexors of the toes.

141 to 149. Musculi lumbricales (Fig. 89 1-5).
(A.) From the posterior border of the aponeurosis plantaris arise :---
(1) UL. lumbricalis digiti I (0.1).
Dugés, tendini-sous-phalangien de pouce, n. 185.

This is inserted into the anterior extremity of the proximal
phalanx.

MUSCLES OF THE HIND LIMB. 109

(2) M. lumbricalis digiti II (7.2).
Dugés, tendini-sous-phal. du I doigt, n. 186 (and 187), double according
to Dugts.
Similarly inserted.
(3 and 4) MM. lumbricales digiti III (7.3).
Dugés, tendini-sous-phal. du III doigt, n. 188, single according to
Duges.
One of these (/3) is inserted into the anterior extremity of the
basal phalanx, the other (/3’) into a corresponding position on the
middle phalanx.

(5) M. lumbricalis digiti 17.
Dugés, tendini-sous-phal. du IV doigt.

Inserted into the anterior extremity of the basal phalanx.

(B.) Arising from the tendons of the flexor Jongus 11I, IV, TV:
(6 and 7) MM. /umbricales digiti IV (2.4’. and 7.4”.).
Dugés, tendini-sous-phalanginien du IV doigt, n. 201, 202.
The first (7.4’) is inserted into the posterior end of the basal pha-
lanx, the second (/.4”) in a similar position into the second phalanx.

(8) I. dumbricalis digiti V (1.5.).
Dugés, tendini-sous-phalangien du V doigt, n. 203.
This arises from the tendon for the fifth toe, rans backwards as a
thin tendon alongside that of the flexor, and is inserted into the
middle phalanx.

Special Muscles of the Separate Toes.
(I.) Muscles of the rudimentary great toe.
150. M. abductor hallucis (Pigs. 88 a.h., 90).
Dugés, tibio-sous-tarsien, n. 163.
This muscle arises from the inner border of the aponeurosis plan-
taris, at the spot where the m. plantaris is inserted, it may therefore

almost be regarded as a continuation of this muscle; it is inserted
into the anterior border of the rudimentary toe.

(I1.) Muscles of the great and first toes.
151. M. adductor longus digiti I (Figs. 89, go ad./1).
Dugés, caleanéo-scaphoidien, n. 164.

This powerful muscle arises from the plantar surface of the cal-
caneum and astragalus ; its fibres converge towards a tendon lying in

110 THE MUSCLES,

its middle, which becomes free towards its posterior end; the
tendon passing inwards under the Jigamentum tarsi transversum
through a groove on the hinder extremity of the astragalus in an
arched direction, to be inserted into the os naviculare, which bears
the rudimentary great toe and the os metatarsi 1.

(III.) Muscles of the first toe.
152. M, abductor longus digiti I (Figs. 88 al.1, go a.b.1).

It takes its origin from the inner border of the aponeurosis plan-
‘aris, and lies on the plantar surface of the adductor hallucis. Its
tendon runs in the hollow which the great toe forms, and is in-
serted into the inner side of the os metatarsi I.

153. M. flexor brevis digiti I (Fig. go F.0.1).

A small, thin muscle, which arises from the anterior extremity
of the os metatarsi IT, and is inserted into the basal phalanx of the
first toe. In this small muscle, and also in the m. /umbrical. dig. V
(Fig. 89 7.5.), the nerve distribution may be very well seen.

154, MW. opponens dig. I (Fig. go op).
Dugés, sous-metatarso-phalangien du pouce, n. 192.

This is situated to the inner side of the preceding muscle, arises
from the os metatarsi IJ somewhat narrow, widens in a fan-like
manner towards the os metatarsi I, into the anterior half of which it
is inserted.

(IV.) Muscles of the second toe.
155. I. flexor metatarsi dig. II (Fig. 90 P.m.2).

Dugés, sous-tarso-metatarsien du IT doigt.—Klein, extensor metatarsi.
By a narrow origin from the hinder end of the calcaneum, poste-
riorly this muscle becomes broader and is inserted, somewhat thinned
out, into the plantar surface of the second os metatarsi.

156. M. fleror dig. II proprius (Fig. go F.p.2).
Dugés, sous-metatarso-phalangien, n. 194.

It arises from the plantar surface of the os metatarsi I], and is
inserted by a thin tendon into the plantar surface of the first
phalanx.

Dugés describes. this and the analogous muscles of the third,
fourth, and fifth toes (7.3, 4, 5) as the imterossei plantares, a no-

MUSCLES OF THE HIND LIMB. 111

menclature which, to me, does not appear correct, as these muscles
lie entirely on the plantar surface, and do not adduct or abduct the

toes, but flex them.

(V.) Muscles of the third toe.

157. UW. flex. metatarsi dig.

III (Ecker), (Fig. go /’.m.3).
Dugés, sous-calcaneo-métatar-
sien du III doigt, n. 174.—

Klein, extensor metatarsi.
Like the _ corresponding
muscle of the second toe
(n. 155), this arises by a small
tendon from the hinder ex-
tremity of the calcaneum, runs
backwards and is mserted into
the plantar surface of the os
metatarsi Il]. The greatest
portion of the muscle lies be-
neath the m. transversus meta-
tarsi (tm), the most anterior
portion, however, lies above
this. Dugés has described
this latter portion as a special
muscle (n. 176, metatarso-
métatarsien du IIT), the same
description holds good for the

second toe (n. 177, Dugés).

158. WM. flexor dig. ILI
proprius (Ecker), (Fig. 91 Fp3).
Dugés, sous-métatarso-phalan-
gien du IIT doigt, n. 195.
Like the corresponding
muscle of the second toe,
this arises from the plantar
surface of the os metatarsi ITI,
and is inserted by a thin tendon
into the plantar surface of the
anterior extremity of the first
phalanx.

Muscles of plantar surface of foot of Rana esculenta.

ab.x M. abductor longus digiti L
abs M. abductor digiti V.
adi M. adductor longus digiti I.
ah. MM. abductor hallucis.

_ Fd.x M. flexor brevis digiti I.

F.m.2, 3, 4 M. flexores metatarsi I, III, [V.
F-p.2, 3, 4, 5 MM. flexor. proprii digit. 2, 3, 4, 5.
F.ph.3, 4, 4’, 5 MM. flexor. phalang. digit. 3, 4, s.
op M. opponens digiti L

tm’
tm” pon. transversi metatarsi 1, 2, 3.
tan”

112 THE MUSCLES.

159. M. flexor phalangum proprius digiti IIT (Reker), (Fig. 91
Fph.3).
Dugés, phalango-phalangien, n. 204.

This arises by tendon from the plantar surface of the basal

Fig. 91.

‘Muscles of plantar surface of foot of Rana esculenta.

a.b.1 M. abductor longus digiti I.

abs M. abductor digiti V.

ad,/.1 M, adductor longus digiti I.

a.h. M., abductor hallucis.

F.b.1 M. flexor brevis digiti I.

F.m.2. 3, 4 M. flexores metatarsi II, IIT, 1V.
F..p.2, 3, 4, 5 MM. flexor. proprii digit. 2, 3, 4, 5.
Fph.3, 4, 4', 5 MM. flexor. phalang. digit. 3, 4, 5.
op M. opponens digiti I. ;

tm’

tm” jon. transyersi metatarsi 1, 2, 3.

tml”

phalanx, and is inserted into
the anterior extremity of the
terminal phalanx.

(VI.) Muscles of the fourth

toe.

160. MW. flexor metatarsi
dig. IV (Fig. 91 F.m.4).
Dugés, métatarso-métatarsien,
n. 175.

Similarly to the correspond-
ing muscle of the third toe,
this one arises from the
hinder extremity of the calca-
neum, and is inserted into the
anterior portion of the plantar
surface of the os metatarsi LV,
but not into the greater portion
of this surface, as in the second
and third os metatarsi.

161. DM. flexor dig. IV
proprius (Fig. 91 Fp4).

Dugés, sous-métatarso-phalan-
gien du IV doigt (interosseus
plantaris), n. 196.

The origin and insertion are
similar to those of the muscles
of the second and third toes.

162. M. flexor brevis dig.
Tr.

A small muscle, which arises
with the m. flexor brevis of the
fifth toe, from enlargement of
aponeurosis plantaris, and is in-
serted into the basal phalanx
of the fourth toe.

MUSCLES OF THE HIND LIMB. 113
163. M. flexor phalangum proprius dig. IV anterior (Fig. gt

F’ph.4).
Dugés, phalango-phalanginien, n. 205.
It resembles the corresponding muscle of the third toe.

164. WM. flexor phalangum proprius posterior (Fig. 91 F.ph.4’).
Dugés, phalangino-phalangettien, n. 209.
This extends from the plantar surface of the second phalanx to
the anterior extremity of the third.

(VII.) Muscles of the small toe.
165. M. abductor dig. V (Fig. 91 a.b.5).
Dugés, calcan¢o-ex-métatarsien du digitule, n. 169.

This muscle arises from the hinder extremity of the calcaneum,
and is inserted into the outer surface of the fifth metatarsal.

166. M. adductor dig. V (Fig. 89 a.d.5).
Dugés, sous-tarso-in-phalangien, n. IgI.

This arises from the cartilage of the plantar aponeurosis, and is
inserted into the hinder end of the fifth metatarsal.

167. M. flexor brevis dig. V (Fig. 89 F.5).
Dugés, sous-tarso-ex-phalangien, n. 190.
Arising from the same place as the preceding, it extends to the
basal phalanx.

168. M. flexor dig. V. proprius (Fig. 91 F.p.5).
(Analogues of Muscles, n. 156, 158, 161; see note at n. 156).—Dugés,
sous-métatarso-phalangien, n. 197 (=inteross. plant.).
This muscle arises from the plantar and inner surfaces of the fifth
metatarsal, and is inserted into the basal phalanx.

169. M. flexor phalangum proprius (Fig. 91 F.ph.5).
Dugés, phalango-phalanginien, n. 206.
Its origin and insertion are as in the corresponding muscles of the
second, third, and fourth toes, n. 159, 163, 164, 169.

170 to 172. MM. interossei (Fig. 91 t.m.).
Dugés, I, 2, and 3, intermétatarsien, n. 170, 171, 172.
These are three muscles with their fibres arranged transversely,
which oceupy the anterior portion of the spaces between the
I

114 THE MUSCLES.

metatarsals, and approximate these. The first arises (¢m’) from the
edge of the plantar surface of the first metatarsal, and is inserted
into the corresponding part of the second: the second (¢m”’) passes
from this point to the third, and the third (#m’”) to the fifth.

B. Muscres or tur Dorsar Svreace.
173. M. flexor tarsi posterior (Ecker), (Fig. 92 Ft.).
Dugés, péronéo-sus-astragal, n. 161.
This is a strong muscle, which has a narrow origin from the
outer side of the tibio-fibula, directly over the distal extremity, and

is inserted into the dorsal surface of the astragalus from the middle
to the distal extremity.

Muscles of the first toe.
174. M. extensor longus dig. I (Fig. 92 ¢./.1).

Dugés, calcanéo-sus-métatarsien du pouce, n, 166. ;

This lies to the outer side of and near the foregoing muscle; it
arises by a long’, strong head from the middle of the caleaneum, runs
obliquely backwards and inwards to unite with a small head which
arises from the common epiphysis of the astragalus and calcaneum,
in common with the m. extensor dig. IT. The muscle so formed

passes into a flat tendon to be inserted into the basal phalanx of
the first toe.

175. M. extensor brevis dig. I (Fig. 92 e.b.1).

A small, short muscle which arises from the os naviculare and is
inserted into the dorsal surface of the first metatarsal.

176. IM. abductor brevis dig. I (Fig. 92 a.b.1).
Dugés, ex-tarso-métatarsien du pouce, n. 168.
This small muscle is situated near the preceding; it arises from
the first bone of the supplemental toe, and is inserted into the inner
side of the first metatarsal.

Muscles of the second toe.

177. M. extensor dig. II longus (Fig. 92 e.1.2).
Dugés, calcanéo-sus-phalangien du IT doigt, n. 182.
This arises from the caleaneum, in common with the m. extensor
longus of the third toe, and is inserted into the basal phalanx of the
second toe by a tendon.

MUSCLES

178. M. extensor
dig. II brevis (Fig. 92
e.b,2).

Dugés, astragalo-sus-

phalangien du II,
n. 183.

This is partly covered
by the preceding muscle:
it arises from the astra-
galus, and unites with
the tendon of the pre-
ceding muscle.

Muscles of the third
toe.

179. WM. extensor
dig. IIT longus (Fig. 92
e.l.3).
Dugés, sus-astragalo-
phalangien du mé-
dius, n. 199.

This arises with the
extensor longus of the
second toe from the
caleaneum : its tendon
unites with that of the
following muscle.

180. WM. extensor
dig. III brevis (Fig. g2
e..3).

Dugés, astragalo-sus-

phalangien du mé-
dius, n. 181.

This muscle arises
from the astragalus,
and is inserted with the
tendon of the preceding
muscle into the dorsal
surface of the basal pha-
lanx.

OF THE HIND LIMB.

Dorsal view of muscles of foot of Rana esculenta.

Fig. 92.

\e

|
!
|

a.b.s M. abductor brevis dig. I.
e.b.x M. extensor brevis dig. L
e.b.2 M. extensor brevis dig. IL
¢.b.3 M. extensor brevis dig. III.

e.b.4 M. extensor brevis x dig. IV.
e.b.4' M. extensor brevis 2 dig. IV.

e.b.5 M. extensor brevis dig. V.
e4.x M. extensor longus dig. L
¢.t.2 M_ extensor longus dig. II.
¢.l.3 M. extensor longus dig. IIL
e.l.4 M. extensor Jongus dig. IV.
e.J.5 ML. extensor longus dig. V.
F.t M. flexor tarsi posterior.

i.2 to iro MM. interossei.

12

115

116 THE MUSCLES.

Muscles of the fourth toe.

181. M. extensor longus dig. IV (Fig. 93 ¢./.4).
Dugés, péroneo-sus-phalangien du IV, n. 178.
A narrow muscle arising in common with the flexor tarsi inf.,
but external to it. It is inserted into the tendinous expansion on
the dorsum of the toe.

182. MM. extensores dig. IV breves (Fig. 93 ¢.b.4 and ¢.b.4’).

Dugés, calcanéo-sus-phalangien and sus-calcanéo-phalanginien, n. 179
and 198,

These two small muscles arise from the caleaneum: one is in-
serted into the basal phalanx, the other, by means of a long
thin tendon, passes along with the tendon of the corresponding
m. interosseus to the second phalanx, to which it is attached.

Muscles of the fifth toe.
183. M. extensor dig. V longus (Fig. 93 e./.5).

Dugés, calecanéo-sus-métatarsien, n. 165.

A strong muscle which covers almost the whole length of the
caleaneum ; it arises from the anterior extremity of this bone, runs
backwards to the outer side of the dorsum of the foot, and is
attached to the outer surface of the fifth metatarsal.

184. M. extensor dig. V brevis (Fig. 93 ¢.b.5).
Dugés,. calcanéo-sus-phalangien du V, n. 180.
This is a long thin muscle, which, together with the muscle last
described, arises from the caleaneum and is inserted into the basal
phalanx of the fifth toe.

185. UW. abductor dig. V brevis (Fig. 93 7.10).
This, the last m. interosseus, arises from the outer side of the
fifth metatarsal, and is inserted into the hinder extremity of the
second phalanx of the same toe.

186 to 195. IM. interossei dorsales (Fig. 93 7.1 to 2.10).

First toe.

(x) The analogue of the first m. interosseus is the m. abductor
brevis dig. I (a.b.1).

(2) The second m. interosseus (7.2) arises from the outer side of
the first metatarsal, and is inserted into the outer surface of the
second phalanx of the same toe, dorsally to the m. opponens and
flexor brevis dig. I.

MUSCLES OF THE HIND LIMB.

Second toe.

(3) The third m. ix-
terosseus (7.3 )takesorigin
from the anterior part
of the outer surface of
the first metatarsal by
a thim tendon; it is
inserted into the inner
surface of the second
phalanx by a similar
tendon.

(4) The fourth m. in-
terosseus (7.4) arises from
the outer side of the
second metatarsal, and
is inserted into the outer
surface of the second
phalanx.

Third toe.

(5) The fifth m. in-
terosseus arises from the
outer surface of the
second metatarsal, and
is inserted by a thin

tendon into the inner |

surface of the second
phalanx of the same
toe.

(6) The sixth arises
from the outer surface
of the third metatarsal,
and is inserted laterally
by a thin tendon into
the hinder extremity of
the second phalanx of
the same toe.

Fourth toe.

(7) The seventh m. in-
terosseus (1.7) arises by a
thin tendon from the

Fig. 93-

|

Dorsal view of muscles of foot of Rana esculenta.

a.b.1 M. abductor brevis dig. I.
e.b.1 M. extensor brevis dig. I.
é.b.2 M. extensor brevis dig. II.
e.b.3 M. extensor, brevis dig. IIL
e.b.4 M. extensor brevis 1 dig. IV.

e.b.4' M. extensor brevis 2 dig. IV.
e.b.5 M. extensor brevis dig. V.
e.l.1 M. extensor longus dig. I.
e.l.2 M. extensor longus dig. II.
e.l.3 M. extensor longus dig. III.
e.l.4 M. extensor longus dig. IV.
¢.l.5 M. extensor longus dig. V.
F.t M. flexor tarsi posterior.

1.2 to 7.10 MM. interossei.

117

118

e.1.5

e.b.5

e.l.4

e.1.3
esb.3
i.10

e.b.4

e.b.4’ if L

1.9

THE MUSCLES.

Dorsal view of muscles of foot of Rana esculenta.

a.b.x M, abductor brevis dig, I,
e.b.1 M. extensor brevis dig. I.
e.b.2 M. extensor brevis dig, IT.
e.b.3 M. extensor brevis dig. III.
e.b.4 M. extensor brevis x dig. IV.
e.b.4’M. extensor brevis 2 dig. IV.
e.b.5 M. extensor brevis dig. V.
e.l.x M. extensor longus dig. I.
e.l.2 M. extensor longus dig. IT.
e.l.3 M. extensor longus dig. II.
e.l.4 M, extensor longus dig. IV.
e.l.s M. extensor longus dig. V.
F.t M, flexor tarsi posterior.

i.2 to i.1o MM. interossei.

hinder extremity of the
astragalus, and by fleshy
fibres from the hinder
extremity of the fourth
metatarsal ; it is mserted
by a thin tendon into
the inner surface of the
second phalanx of the
same toe.

(8) The eighth m, i-
terosseus (1.8) takes its
origin from the outer
surface of the fourth
metatarsal and from the
inner surface of the fifth :
it is inserted into the
hinder extremity of the
second phalanx.

Fifth toe.

(9) The ninth m. i-
terosseus (1.9) arises from
the inner surface of the
fifth metatarsal, and is
inserted into the hinder
extremity of the second
phalanx.

(10) The tenth m. i-
terosseus has already been
described as the abductor
digitt V brevis (Fig. 94
2.10).

If we take the
fourth toe as the axis
of movement, the first,
third, fifth, seventh,
eighth, and tenth mm.
interossei will abduct
from an imaginary line
which runs through this
toe. ‘The second, fourth,

MUSCLES OF THE SKIN. 119

sixth, and ninth will adduct towards this lme. If we compare
them with those of man (in whose case the second toe affords the
central line), those of the first group must be regarded as mm. inter-
osset dorsales, of the latter as plautares. Duges holds all these
interossei (with the exception of the first, abductor brevis dig. 1) to
be mm. interossei dorsales (métatarso-sus-phalangettiens, n. 210, 211,
212, 214, 215, 216, 218, 219). Those which I have described as
flexores proprii digitorum, he regards as interossei volares.

V. MUSCLES OF THE SKIN.

196. M. cutaneus pectoris (Fig. 95 cp).
Dugés, abdomino-guttural, n. 53.— Klein, abdomino-cutaneus.—Zenker,
subeutaneus pectoris.

This is an elongated quadrangular muscle, attached by its hinder
margin to the side of the xiphisternum, and to the superficial
surface of the aponeurosis of the m. obliquus externus. The fibres
course forwards and .
slightly outwards to be Fig. 95.
inserted, at a very acute
angle, into the skin : lying
between the two muscles
and attached to them on
either side is a thin fas-
cia, which, together with
the muscles and the sep-
tum thoracicum, assists in
closing a triangular space
between these structures
and the deeper muscles.

The thinness and trans-
parency of this muscle
render it especially suit- Pectoral region of Rana esculenta.
> ° : cp M. eutaneus pectoris.
able for the investigation ?” Port. abdominalis of the m. pectoralis.

of nerve-terminations !.
197. M. cutaneus dorsi (Fig. 96 ed).
Dugés, pubio-dorso-cutané, n. 56.—Zenker, cutaneus iliacus.
This muscle has a narrow origin in the space between the muscles

? Kolliker, Mikrosk. Anatomie, 1866, vol. II. 1, p. 247; Reichert, Miiller’s Archiv,
1851, p. 29, Pl. 1; K@lliker, Untersuchungen iiber die letzten Endigungen der Nerven
in den Muskeln des Frosches ; Leipzig, Engelmann, 1862.

120 THE MUSCLES.

of the belly and of the thigh, and is here inserted into the fasciae,
which are attached to the pubic symphysis; it passes inwards and

Fig. 96.

Hind portion of back and thigh of Rana esculenta.

ed M., cutaneus dorsi,

cx. Coccyx.

gl, M. glutaeus,

H Skin reflected to left side,
oe M. obliquus externus,

rf M. rectus femoris anterior.
sm M. semimembranosus,

v.e M. vastus externus.

upwards to the outer side of
the anterior insertion of the
m. rectus femoris anticus, then
widens and is inserted by di-
verging fibres into the inner
surface of the skin of the
hinder portion of the back.

198. M. coccygeo-cutaneus.
Dugés, coccy-dorso-cutanés,
n. 57,

The muscular fibres which
Dugés has described under
this name, lie covered by the
m. pyriformis, behind the m.
coccygeo-iliacus, etc., and above
the muscles of the rectum.
They arise from the hinder
extremity of the urostyle:
they appear to be connected
with the rectal muscles, and
pass outwards to be attached
to the skin.

Among the cutaneous muscles may perhaps be included the

m. submaxillaris (p. 62).

The fibrils passing from the flexor tendons to the warty bodies
on the plantar surface of the toes are described! with the skin

(p. 373)-

1 Compare Klein, Beitriige zur Anatomie der ungeschwinzten Batrachier (R. tem-
poraria, L.) : Jahreshefte des Vereins fiir vaterliindische Naturkunde in Wiirttemberg,

1850, p. 72.

SECTION IIL.

aa } a) i;
THE NERVOUS SYSTEM. |

THE NERVOUS SYSTEM,
LITERATURE.

Ahlborn, F., Ueber die Bedeutung der Zirbeldriise. Zeit. f. wiss. Zool. 1884.
_ Vol. XL, pp. 331-337.

Allen, H., The Spinal Cord in Batrachia and Reptilia. Proc. Acad. Nat. Sci.
Philadelphia. 1883, pp. 56-57.

Arndt, A. W., Untersuchungen iiber die Ganglienkérper des Nervus sympathicus.
Arch. f. mikrosk. Anat. 1874. Vol. X, pp. 208-241.

Arndt, R., Untersuchungen iiber die Endigung der Nerven in den quergestreiften
Muskelfasern. Arch. f. mikrosk, Anat. 1873. Vol. IX, p. 481.

Arndt, R., Untersuchungen tiber die Ganglienkérper der Spinalganglien. Arch. f.
mikrosk, Anat. 1875. Vol. XI, p. 140.

Arnold, J., Zur Histologie der Lungen des Frosches. Virchow’s Arch. 1863.
Vol. XXVIII, p. 433.

Arnold, J., Histologische Verhiltnisse des Frosch-Sympathicus. Centralbl. f. d.
med. Wiss. 1864, p. 657.

Arnold, J., Ueber die feineren histologischen Verhiltnisse der Ganglienzellen
in dem Sympathicus des Frosches. Virchow’s Arch. 1865. Vol. XXXII,

p. I.

Arnold, J., Die Spinalfasern im Sympathicus des Frosches. Arch. f. Anat. und
Physiol. 1866, p. 398.

Arnold, J., Das Gewebe der organischen Muskeln. Leipzig, 1869; and Chap. IV
in Stricker’s Handbook.

Arnstein, C., and Gonjaew, K., Ueber die Nerven des Verdauungskanals. Bericht.
f. Physiol. u. Histologie. Mittheilung. aus. d. 4 Vers. wissensch, Naturforsch. zu
Kasan, Pfliiger’s Arch. d. ges. Physiol. 1874. Vol. VIII, pp. 614-615.

Aubert, H., Die Innervation der Kreislaufsorgane, Hermann’s Handbuch der Phy-
siologie. Leipzig, 1880. Vol. IV, Pt. I, p. 377.

Axmann, De Gangliorum systematicis structura persitiori eiusque functionibus.
Berolini, 1847.

Axmann, Beitriige zur mikroskopischen Anatomie und Physiologie des Ganglien-
nervensystems. 1853, p. 20.

Baculo, B., Nuove ricerche intorno lapparechio ganglionare intrinseco dei cuori
itaftici: Naples, 1885.

Balfour, F. M., Treatise on Comparative Embryology. London, 1880.

Balfour, F. M., Handbuch der vergleichenden Embryologie. Aus dem Englischen
von B. Vetter. Jena, 1880.

Beale, L. 8., On the Structure and Formation of the so-called Apolar, Unipolar,
and Bipolar Nerve-cells of the Frog. Phil. Trans. 1863, p. 543. (Hyla
arborea.)

Beale, L. 8., Further observations in favour of the view that nerve-fibres never end
in voluntary muscle. Proc. Roy. Soc. 1863. Abstract in Quart, Journ. Micros.
Sci. 1863. Vol. XII, p. 668.

Beale, L. S., New observations upon the structure, etc. of certain nervous centres.
Proc. Roy. Soc. 1860. Vol. ITT.

Beale, L. S., On the Distribution of Nerves to the elementary fibres of Striped
Muscle. Phil. Trans. 1864, p. 611.

LITERATURE. 123

Beale, L. S., Of very fine nerve-fibres ramifying in certain fibrous tissues and
trunks, and plexuses consisting entirely of very fine nerve-fibres in the bladder
of the frog. Beale’s Archives of Medicine, 1864. Vol. IV, pp. 19-251.

Beard, J., The Ciliary or Motor-oculi ganglion and the Ganglion of the ophthalmicus
profundus in Sharks. Anatom. Anzeiger. 1887. Vol. II, p. 565.

‘Beck, K., Zur Kenntniss der Herznerven. Arch. f. mik. Anat. 1885. Vol. XXIV,

- II-Ig.

Bellonci, G. Intorno alla struttura e alle connessioni dei lobi olfattorii negli
arthropodi superiori e nei vertebrati. Atti Accad. Lincei Ann. 279 Mem.
Accad. Bologna, Vol. XIII, pp. 555-564: and in Arch. Ital. Biol. 1883;
Vol. III, pp. 191-196.

Bellonci, G., Sulla terminazione centrale del nervo ottico nei mammiferi. Mem.
Accad. Bologna, Vol. VI, pp. 199-205: and in Arch. Ital. Biol. 1884, Vol. VI,
pp. 405-411. ‘

Bidder, F. H., Die Endigungsweise der Herzzweige des N. vagus beim Frosch.
Arch, f. Anat. u. Physiol. 1839, p.1.

Bidder, F. H., Zur Lehre yon dem Verhialtniss der Ganglienkérper zu den Nerven-
fasern. Nebst einem Anhange von Dr. A. W. Volkmann. Leipzig, 1847.

Bidder, F. H., Zur Lehre vom Verhalten der Ganglienkérper, u.s.w. Leipzig,
1847.

Bidder, F. H., Ueber functionelle verschiedene und raumlich getrennte Nerven-
centra im Froschherzen. Arch. f. Anat. u. Physiol. 1852, p. 163.

Bidder, F. H., Endigungsweise der Herzzweige des N. vagus beim Frosch. Arch.

_ , Anat. und Physiol. 1868, p. 1.

Bidder, F. H., Zur naheren Kenntniss des Froschherzens und seiner Nerven.
Arch, f. Anat. u. Physiol. 1866, p. 1. :

Bidder, F. H., and Kupffer, Untersuchungen iiber die Textur des Riickenmarks.
Leipzig, 1857.

Bidder, F. H., and Volkmann, A. W., Die Selbstindigkeit des sympathischen
Nervensystems, durch anatomische Untersuchungen nachgewiesen. Leipzig,
1842.

Bidder and Gregory, Beitriige zur Physiologie der Herzbewegung beim Frosche.

. Dorpat, 1865.

Bikfalvi, K., Ueber die Hornscheide der markhaltigen Nervenfasern. Orvoster-
mészettudomanyi Ertesito, 1884, p. 133. Abstract in Centralbl. f. d. med.
Wiss. 1886, p. 34.

Biroege, E. A., Die Zahl der Nervenfasern u. der motor. Ganglienzellen im Riicken-
mark des Frosches. Arch. f. Anat. u. Physiol. 1882. Physiol. Abth., p. 435.

Bischoff, Nervi accessorii Willisii anatomia et physiologia. Heidelberg, 1832.

Blasius, G., Gerardi Blasii Anatomia Animalium. Amstelodami, 1681.

Blattmann, A., Mikrosk. anatom. Darstellung der Centralorgane des Nervensystems
bei den Batrachiern. Dissert. Ziirich, 1850.

Boll, F., Studj sulle immagini microscopiche della fibra nervosa midollare. Atti
della R. accademia dei Lincei, 1876-1877. Vol. II.

Boll, F., Ueber Zersetzungsbilder der markhaltigen Nervenfasern. Arch. f. Anat. u.
Physiol. 1877, p. 288.

Bojanus, Testudinis anatomia. 1819.

Bosse, De ganglior. spinal. vi in nutr. radic. poster. nervor. spinal. Dissert. 1859.

Boveri, T., Beitrage zur Kenntniss der Nervenfasern. Abhandl. d. bayr. Akad. d.
Wiss. 1885. Vol. XV, p. 421.

Bremer, D. L., Die Nerven der Capillaren, der kleinen Arterien und Venen.
Arch. f. mik. Anat, Vol. XXI. 1882, p. 663.

Bremer, L., Ueber die Muskelspindeln sowie iiber Structur, Neubildung u. Inner-
vation der quergestreiften Muskelfaser. Waldeyer’s Arch. 1883. Vol. XXII,
p. 2.

124 THE NERVOUS SYSTEM.

Bremer, L., Ueber die Endigungen der markhaltigen und marklosen Nerven im
quergestreiften Muskel. Arch. f. mikrosk, Anat. 1882. Vol. X XI, p. 165.
Brenner, A., Ueber das Verhiltniss des nervus laryngeus inferior vagi zu einigen
Aortenvarietiiten des Menschen und zu dem Aortensystem der durch Lungen
athmenden Wirbelthiere tiberhaupt. His u. Braune’s Arch. 1883, pp. 373-397-

Budge, J., Ueber den Verlauf der Nervenfasern im Riickenmark des Frosches,
Arch. f. Anat. u. Physiol. 1844, p. 160.

Budge, J., Ueber die Bewegung der Iris. (Concerning ganglia of motor-oculi, p. 36.)

Budge, J., Wagner’s Handwérterb. d. Physiologie. 1846. Vol. III, p. 451.

Burdon-Sanderson, J., Circulation of the Blood. Handbook for the Physiological
Laboratory. London, 1873.

Calberla, E., Ueber die Endigungsweise der Nerven in den quergestreiften Muskeln
bei Amphibien. Zeit. f. wiss. Zool. 1874. Vol. XXIV, p. 164.

Calberla, E., Studien iiber die Entwicklung der quergestreiften Muskeln und Nerven
der Amphibien und Reptilien. Arch. f. mik. Anat. 1875. Vol. XI, p. 442.

Carus, Versuch einer Darstellung des Nervensystems und Gehirns. Leipzig, 1814.

Champness, F., The septum atrium of the Frog and Rabbit. Journ. of Anat. and
Physiol. 1874.

Christmas-Dirckinck-Holmfeld, J., Experimentaluntersuchungen iiber den Bau
der Regio olfactoria. Nord. med. ark. 1883. Vol. XV, No. 3.

Ciaccio, G. V., On the nerves of the Cornea, and their distribution in the corneal
tissue of man and animals. Proc. Roy. Soc. 1863. Abstract in Trans. Micros.
Soc. London, 1863. Vol. XI, pp. 77-93.

Ciaccio, G. V., On the distribution of nerves to the skin of the frog, with physio-
logical remarks on the ganglia connected with the cerebro-spinal nerves. Quart.
Journ. Micros. Sci. 1864. Vol. IV, pp. 15-31.

Ciaccio, G. V., Intorno alla minuta fabbrica delle pelle Rana esculenta. Giornale
di Scienze naturali ed economiche. Palermo, 1866. Vol. IT, p. 103.

Clarke, J. Lockhart, Ueber den Bau des Bulbus olfactorius und der Geruchsschleim-
haut. Zeit. f. wiss. Zool. 1862. Vol. XI, p. 31.

Cornil and Ranvier, A Manual of Pathological Histology. London, 1880, p. 359,
Fig. 199 (Ganglia of heart).

Courvoisier, G., Beobacht. tiber den sympathischen Griinzstrang. Arch. f. mik.
Anat. 1866. Vol. II, p. 13.

Courvoisier, L. G., Ueber die-spinalen und sympathischen Zellen des Frosches.
Centralbl. f. d. med. Wiss. 1867, p. 897.

Courvoisier, G., Ueber die Zellen der Spinalganglien, sowie des Sympathicus beim
Frosch. Arch. f. mikrosk. Anat. 1868. Vol. IV, p. 125.

Cuvier, Lecons d’anatomie comparée. 2nd Edit. Vol. II.

Cyon, Ueber die Nerven des Peritoneum. Berichte tiber die Verhandlungen d.
konigl. siichs. Gesellsch. d. Wissensch. zu Leipzig. Math.-physik. Classe. 1868.
Vol. XX, p. 119.

Czermak, J. N., Ueber die Hautnerven des Frosches. Arch. f. Anat. u, Physiol.

"1849, p- 252. Leipzig, 1869.

Czerniak, J. N., Ueber die Herznerven des Frosches, Rana temporaria. Arch, f.
Anat. u. Physiol. 1851, p. 160.

v. Darkschewitsch, L., Zur Anatomie der Glandula pinealis. Neurol. Cent. Bl.
1886. Vol. V, p. 29.

v. Deen, De differentia et nexu inter nervos vitae animalis et vitae organicae.
Diss. inaugur. Lugduni-Bat., 1834.

v. Deen, Over de zijdelingsche Takken dar swervende zenuw van den Proteus
anguineus, aus Bijdragen tot de Naturkundige. Wettenschappen, 1834.

v. Deen, Ueber den Ramus lateralis n. vagi bei den Batrachiern. Arch. f. Anat. u.
Physiol. 1834, p. 477 (abstract from Diss. inaugur. De differentia et nexu inter
nervos vitae animalis et vitae organicae), Lugduni-Bat.

LITERATURE. 125

Deiters, O., Untersuchungen fiber Gehirn und Riickenmark. Braunschweig, 1365.
Denissenko, G., Zur Frage iiber den Bau der Kleinhirnrinde bei verschiedenen
Klassen von Wirbelthieren. Arch. f. mikrosk. Anat. 1877. Vol. XIV,

Pp. 203-

Dietl, M. J., Beobachtungen iiber Theilungsvorgange an Nervenzellen. Wiener
Sitzungsber. 1874. Vol. LXIX, Pt. II, p. 71.

Dietl, M. J., Casuistische Beitrage zur Morphologie der Nervenzellen. Wiener
Sitzungsber. 1874. Vol. LXIX, Pt. III, p. 80.

Dogiel, J., Die Ganglienzellen und Nerven des Herzventrikels beim Frosche. Arch.
£. mikrosk. Anat. 1877. Vol. XIV, p. 470.

Dogiel, J., Die Ganglienzellen des Herzens bei verschiedenen Thieren und beim
Menschen. Arch. f. mikrosk. Anat. 1877. Vol. XVII, p. 471.

Dogiel, J., Die Nervenzellen und Nerven des Herzventrikels beim Frosche. Arch.
f. mikrosk. Anat. 1882. Vol. XXI, p. 21.

Duméril, A. M. C., and Bibron, G., Erpétologie générale ou histoire naturelle com-
plete des reptiles. Paris, 1841.

Eberth, Untersuchungen zur normalen und pathologischen Anatomie der Froschhaut.
Leipzig, 1869.

Ecker, A., Icones physiologicae. Leipzig, 1851 to 1859.

Eckhard, C., Beitrage zur Anatomie und Physiologie. Giessen, 1860. Vol. II.

Eckhard, C., Experimentale Physiologie des Nervensystems. Giessen, 1867, p. 208
(Ganglion cells of heart).

Edinger, L., Nachtrag zu dem Bericht iiber Leistungen auf dem Gebiete der Ana-
tomie des Centralnervensystems. Schmidt's Jahresb. 1887.

Egorow, W., Ueber die Nervenzellen der Lungen. Centralbl. f. med. Wiss. 1879.
Vol. XVII, p. 305.

Eichholtz, De piscium atque amphibiorum nudorum lobis opticis atque olfactoriis.
Berolini, 1841.

Engelmann, T. W., Zur Physiologie des Ureter. Pfliiger’s Arch. f. d. ges.
Physiol. 1869. Vol. II, p. 243. (Treats also of histological details of frog’s
bladder.

Engelmann, T. W., Ueber die Discontinuitat des Axencylinders und den fibrillaren
Bau der Nervenfasern. Pfliiger’s Arch. f. d. ges. Physiol. 1880. Vol. XXII,
p- I.

Engelmann, T. W., Der Bulbus aortae des Froschherzens. Pfliiger’s Arch. f. d.
ges. Physiol. 1882. Vol. XXIX, p. 425.

Fischer, E., Ueber die Endigung der Nerven im quergestreiften Muskel der Wir-
belthiere. Arch. f. mik. Anat. 1876. Vol. XIII, pp. 365-390.

Fischer, J. G., Amphibicrum nudorum néurologiae specimen primum. Berlin,
1843; and Arch. f. Anat. u. Physiol. 1844, p. 57.

Fowelin, C., De causa mortis post nervos vagos dissectos instantis. Inaug. Dissert.
Dorpati, 1851.

Frenkel, 8., Nerv und Epithel am Froschlarvenschwanze. Arch. f. Anat. u.
Physiol. 1886. Physiol. Abth., p. 405.

a! an d. Histologie u. Histochemie d. Menschen. 3rd Edit., p. 3.41. (Ganglia

heart.)

Friedlander, Ueber die nerviésen Centralorgane des Froschherzens. Untersuch.
aus d. physiol. Laborat. za Wirzburg. 1867.

Frommann, Ueber Structur der Nervenzellen. Virchow’s Arch. 1864. Vol. XXXI,
p- 129.

Fubini, 8.,Gewicht des centralen Nervensystems im Vergleich zu dem Kérpergewicht
der Thiere, bei R. esculenta u. R. temporaria, Moleschott’s Untersuchungen zur
Naturlehre d. Menschen. 1881. Vol. XII, pp. 455-461.

Gad, J., Ueber Centrum und Leitungsbahnen im Riickenmark des Frosches. Ver-
handl. der Physiol. Gesellsch. zn Berlin, No. 10, 1884. Arch. f. Anat. v. Physiol.

126 THE NERVOUS SYSTEM.

1884, p. 304. Verhandl. d. physick.. med. Gesellsch. zu Wiirzburg. 1884.
Vol. XVIII.

Gaskell, W. H., On the augmentor (accelerator) nerves of the heart of cold-blooded
animals. Journ. of Physiol. 1884. Vol. V, p. 46.

Gaskell, W. H., and Gadow, On the anatomy of the cardiac nerves in certain cold-
blooded animals. Journ. of Physiol. 1884. Vol. V, p. 362.

Gaskell, W. H., The Structure, Distribution, and Function of the Nerves which
innervate the Visceral and Vascular System. Journ. of Physiol. 1886. Vol.
VII,.p. 1.

Gegenbaur, C., Grundziige der vergleichenden Anatomie. 1870. 2nd Edition,
p- 728.

Gerlach, J., Ueber das Verhalten der Nerven in den quergestreiften Muskelfiden
der Wirbelthiere. Sitzungsber. d. phys.-med. Societiit zu Erlangen. 1873.
Vol. V, p. 97.

Gerlach, J., Das Verhiltniss der Nerven zu den willkiirlichen Muskeln der Wir-
belthiere. Leipzig, 1874.

Gerlach, J., Ueber die Nervenendigungen in der Muskulatur des Froschherzens.
Virchow’s Arch, 1876. Vol. LXVI, pp. 187-223.

Gerlach, J., Das Verhiltniss der nervésen und contractilen Substanz d. querge-

‘streiften Muskels. Arch. f. mikrosk. Anat. 1877. Vol. XIII, p. 399.

Giuliani, Sulla struttura del midollo spinale della Lacerta viridis, Memorie della
R. academia dei Lincei. Roma, 1878. .

Goette, A., Kurze Mittheilungen aus der Entwicklungsgeschichte der Unke. Arch.
f. mik. Anat. 1873. Vol. IX, p. 396.

Goette, A., Entwickelungsgeschichte der Unke, Leipzig, 1875.

Golgi, C., Sulla fina anatomia degli organi centrali del sistema nervoso. Milano,
1866.

Golgi, C., Sui Nervi dei Tendini dell’ Uomo e di altri Vertebrati e di un nuovo
organo nervoso terminale muscolo-tendineo. Estr. dalle Memoire della Reale
Acc, di Torino. 1880. Vol. XXXII, p. 29. ,

Gonjaew, K., Die Nerven des Nahrungsschlauches. Arch. f. mikrosk, Anat. 1875.
Vol: XI, pp. 479-496.

de Graaf, H. W., Zur Anatomie u. Entwicklung d. Epiphyse bei Amphibien u.
Reptilien. Zool. Anz. 1886. Vol. IX, No. 219.

de Graaf, H. W., Over den bouw der epiphyse bij de amphibien. Tijdschr. der
Nederl. dierkundige Vereeniging. 1886. Vol. II, p. 1.

de Graaf, H. W., Bijdrage tot de kennis van der bouw ende entwickkeling der
epiphyse bij amphibién en reptilién. Inaug.-Diss. Leiden, 1886. Abstract in
Centralbl. f. d. med. Wiss. 1886, p: 706.

Grant, R., Comparative Anatomy. London, 1839.

Grant, R., Umrisse der vergleichenden Anatomie von R. E. Grant. Aus dem En-
glischen von C.C. Schmidt, M.D. Leipzig, 1842.

Gruenhagen, A., Ueber ein Endothelialelement der Nervenprimitivscheide. Arch.
f. mik. Anat, 1884. Vol, XXIII, p. 380.

Gscheidlen, R., Ueber Nervenendigung in den glatten Muskelfasern. Arch. f.
mik. Anat. 1877. Vol. XIV, pp. 320-332.

Guillot, Exposition anatomique de l organisation des centres nerveux dans les quatres

» classes d’animaux vertébrés. Paris, 1844.

Hannover, A., Die Chromsiure, ein vorziigliches Mittel bei mikroskopischen Unter-
suchungen. Arch. f. Anat. u. Physiol. 1840, pp. 549-556. (Describes the con-
nection between fine fibres and small ganglia in the central nervous system of
fish, frogs, and birds.)

Hannover, A., Recherches microscopiques sur le systtme nerveux. Recherches
sur le cerveau de la grenouille, pp. 20-22. Kopenhagen, Paris, and Leipzig,

1844.

—_—_— -<-

LITERATURE. 127

Harless, Ern., Ueber die Functionen verschiedener Parthien des Riickenmarks der
Amphibien. Arch. f. Anat. u. Physiol. 1846, p. 74.

Hartmann, D. R., Ueber die Endigungsweise der Nerven in den Papillae fungi-
formes der Froschzunge. Arch. f. Anat. u. Physiol. 1863, p. 634.

Heidenhain, Disquisitiones de nervis organisque centralibus cordis. Dissert. inaug.
Berol. 1854; and in Arch. f. Anat. u. Physiol. 1858, p. 479.

Hénoque, Du mode de distribution et de la terminaison des nerfs dans les muscles
lisses. Arch. de l’Anat. et dela Physiol. 1870.

Hensen, V., Ueber die Entwicklung des Gewebes und der Nerven im Schwanze der
Froschlarve. Virchow’s Arch. 1864. Vol. XXXI, p. 51.

Hensen, V., Ueber die Nerven im Schwanz der Froschlarven. Arch. f. mik. Anat.
1868. Vol. IV, p. 111.

Hesse, F., Zur Kenntniss der peripherischen markhaltigen Nervenfaser. His u.
Braune’s Arch. f. Anat. u. Physiol. 1879. Vol. VI, p.89. Abstraet in Centralbl.
f. d. med. Wiss. 1880, p. 324.

His, W., Ueber die Endigung der Gefiissnerven. Virchow’s Arch. 1863. Vol.
XXVIII, p. 427.

Hjelt, De nervis cerebralibus parteque cephalica nervi sympathici Bufonis cinerei
adnotata quaedam. Helsingforsiae, 1852.

Hoffmann, C. K., in Bronn’s Klassen und Ordnungen des Thierreichs. Leipzig and |
Heidelberg, 1873-1878. Vol. VI. Amphibia.

Holl, M., Ueber den Bau der Spinalganglien. Wiener Sitzungsber. 1876. Vol.
LXXTII, Pt. IT, p. 31.

Horn, H., Ueber die Endschlingen des Gernchsnerven (Nervus olfactorius) in Rana
temporaria. Arch. f. Anat. und Physiol. 1850.

Huizinga, D., Untersuchungen iiber die Innervation der Gefisse in der Schwimm-
haut des Frosches. Pfliiger’s Arch. f. d. ges. Physiol. 1875. Vol. XI, pp.
207-221.

Huxley, T. H., Article Amphibia. Encyclopaedia Britannica, gth Edition.

Isquierdo, V., Ueber die Endigungsweise der sensiblen Nerven. Arch. f. mikrosk.
Anat. 1880. Vol. XVII, p. 367.

Jacubowitsch, M. N., Terminaisons des nerfs 4 la périphérie et dans les différents
organes ou terminaisons périphériques du syst?me nerveux en général. Comptes
rendus. 1860. Vol. L, p. 859.

Jantschitz, J., Materialien zur Anatomie der Nerven des Pericardiums. Rudneft’s
Journ. f. normale u. patholog. Histologie u. klinische Med. St. Petersburg,
1874, pp. 417-442. (In Russian, Abstract in Centralbl. f. d. med. Wiss.
1874.)

Johnson, A., and Sheldon, L., Note on the Development of the Newt (Triton
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Kandarazki, M., Ueber die Nerven der Respirationswege. His u. Braune’s Arch.
f, Anat. u. Entwickelungsgesch. 1881, pp. I-11.

Kanhel, G., Studien tiber Innervation der Lymphherzen. Medic. Jahrb. 1886,
PP- 392-420.

Karabanowitsch, D., Ueber den Bau des Riickenmarkes vom Frosche. Arbeiten
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Key, A., and Retzius, G., Studien in der Anatomie des Nervensystems. Arch. f.
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Elebs, “iy Die Nerven der organischen Muskeln. Centralbl. f. wiss. Med. 1863,
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Klebs, E., Die Nerven der organischen Muskelfasern. Virchow’s Arch. 1865. Vol.
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Klein, E., Beitrige zur Anatomie der ungeschwiinzten Batrachier. Wiirttemberger
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128 THE NERVOUS SYSTEM,

Klein, EB., Auerbach’s Plexus in the Intestine of Frog and Toad. Quart. Journ.
Microsc. Sci. 1873. Vol. XIII, Pp: 377-380.

Klein, E., Some remarks on the finer nerves of the Cornea. Monthly Micros. Journ.
1872. Vol. VII, pp. 156-164.

Klein, E., On the peripheral distribution of non-medullated nerve-fibres, Quart.
Jouen Microsc. Sci. 1871. Vol. XI. New Series, p. 405. :

Klug, F., Ueber die Herznerven des Frosches. Arch. f. Anat. u. Entwicklungs-
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Klug, F., Ueber die Beschleunigungsnerven des Froschherzens. Centralbl. f. med.
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v. Kélliker, A., Neurologische Bemerkungen. Zeit. f. wiss. Zool. 1849. Vol. L
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v. Kélliker, A., Handbuch der Gewebelehre. 5th Edit. 1861, p. 163. (On nervye-
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v. K6élliker, A., Vorlaufige Mittheil. iiber den Bau des Riickenmarks bei niederen
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v. Kélliker, A., Ueber die letzten Endigungen der Nerven in Muskeln des Frosches.
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v. Kélliker, A., Untersuchungen iiber die letzten Endigungen der Nerven. Zeit. f.
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v. Kélliker, A., Ueber die Vitalitiit der: Nervenrohren der Frésche. Wiirzburg.
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Kollmann, J., Ueber den Verlauf des Lungenmagennerven in der Bauchhohle.
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Kollmann, J., and Arnstein, Die sympathischen Ganglienzellen des Frosches.
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K6nigstein, L., Beobachtungen fiber die Nerven der Cornea und ihre Gefiisse.
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K6ppen, M., Zur Anatomie des Froschgehirns. Neurologisches Centralblatt. 1888.

Képpen, M., Zur Anatomie des Froschgehirns. Arch. f. Anat. u. Physiologie,
1888.

Korybutt-Daszkiewicz, W., Ueber die Entwicklung der Nerven aus Plasmazellen
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Krause, W., Die Nervenendigungen in den Froschmuskeln. Internat. Monats. f.
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Krause, W., Ueber die Driisennerven. Zeitschr. f. rat. Medicin. Dritte Reihe.
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Krohn, A., Ueber den Ramus lateralis n. vagi bei niedrigen Amphibien. Fror.
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Krohn, A., Ergiinzungen der Nachricht tiber den n. lateralis der Froschlarven.
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Kihne, W., Die Endigungsweise der Nerven in den Muskeln und das doppelsinnige
Leitungsvermégen der motorischen Nervenfaser. Monatsbericht der Kénigl.
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Kiihne, W., Die peripher. Endorgane der motorischen Nerven. Leipzig, 1862.

Kiihne, W., Zur Lehre von den Endplatten der Nervenhiigel. Virchow’s Arch.
1865. Vol. XXXIV, p. 412.

Kihne, W., Zur Histologie der motorischen Nerven. W. Kiihne’s Heidelberger
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1879, P- 495.

Kiihne, W., Ueber Nervenendigungen in den Muskeln nach Beobachtungen von M. B.
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?

LITERATURE. 129

Kihne, W., Widerlegen der Bemerkung E. du Bois-Reymonds iiber mehrfache

Nervenendigungen in einer Muskelfaser. Zeitschr. f. Biol. 1884. Vol. XX,
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Kanne, W., Ueber das doppelsinnige Leitungsvermiégen der Nerven. Zeitschr. f.
Biol. 1886. Vol. XXII, p. 305.

Kuhnt, J. H., Die peripherischen markhaltigen Nervenfasern. Arch. f. mik. Anat.
1877. Vol. XIII, p. 427.

Kupffer, De medullae spinalis textura in Ranis. 1854. Dissert. inaug.

Kutschin, Zur Structur des Nervengewebes. Centralbl. f. d. med. Wiss. 1865,

561.

Kittner, C., De origine n. sympathici ranaram, ex nervorum dissectorum muta-
tionibus dijudicatur. Dorpat, 1854. Dissert. inaug.

Lahousse, P., Die Structur des Nervenplexus in der Vorhofscheidewand des Frosch-
herzens. Arch. f. Anat. u. Physiol. 1886, p. 19.

Langerhans, P., Zur Histologie des Herzens. Virchow’s Arch. 1873. Vol. LVIII,
p- 65- .

Lantermann, A. J., Bemerkungen iiber den feineren Bau der markhaltigen Nerven-
fasern. Centralbl. f. d. med. Wiss. 1874, p. 706.

Lantermann, A. J., Ueber den feineren Bau der markhaltigen Nervenfasern.
Arch. f. mikrosk. Anat. 1877. Vol. XIII, p. 1.

Lavdowsky, N., Die feinere Structur und die Nervenendigungen der Froschharn-
blase. Arch. f. Anat. und Physiol. 1872, p. 55.

Lavdowsky, N., Das Saugadersystem und die Nerven der Cornea. Arch. f. mikrosk.
Anat. 1872. Vol. VILL, p. 538.

Lavdowsky, N., Zum Nachweis der Axencylinderstructurbestandtheile von mark-
haltigen Nervenfasern. Centralbl. f. d. med. Wiss. 1879, pp. 865, 881.

Lavdowsky, N., Ueber die Fortsiitze der Nervenzellen in den Herzganglien. Arch.
f. mik. Anat. 1887. Vol. X XIX, p. 609.

Lehmann, J. C., Ueber die Nervenendigungen und das Vorkommen von mikro-
skopischen Ganglien in den Gefiisswandungen. Zeit. f. wiss. Zool. 1864. Vol.
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Lenhossek, M., Untersuchungen iiber die Spinalganglien des Frosches. Arch. f.
mikrosk. Anat. 1886, Vol. XX VI, pp. 370-453.

Leuret, Anatomie comparée du systtme nerveux de Vhomme et des animaux
vertébrés. Paris. Vols. I, IT.

Lipmann, Die Nerven der organischen Muskeln. Dissert. Berlin, 1869.

Lominsky, T., Zur Frage iiber die Teilung der Nervenzellen. Centralbl. f. d. med.
Wiss. 1882, p. 434.

Longet, Anatomie et Physiologie du syst#me nerveux de Phomme et des animaux

~ vertébrés. Paris, 1842.

Léwit, M., Die Nerven der glatten Muskulatur. Wiener Sitzungsb. 1875. Vol.
LXXI, Pt. IT, p. 355.

Léwit, M., Beitrige zur Kenntniss der Innervation des Froschherzens. Pfliiger’s
Arch. f. d. ges. Physiol. Vol. XXIII, p. 313; Vol. XXV, p. 399; Vol. XXVIII,
p- 312; Vol. XXIX, p. 469.

Léwit, M., Ueber die Gegenwart von Ganglienzellen im Bulbus aortae des Frosch-
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Léwit, M., Beitrage zur Kenntniss der Innervation des Herzens. Pfliiger’s Arch. f.

d. ges. Physiol. 1881. Vol. XXV, pp. 399-496.

Luchsinger, B., Zur Innervation d. Lymphherzen. Pfliiger’s Arch. f. d. ges. Physiol.
1880. Vol. XXIII, p. 304.

Ludwig, C., Ueber die Herznerven des Frosches. Arch. f. Anat. u. Physiol. 1848,
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Macallum, A. B., The Nerve Terminations in the Cutaneous Epithelium of the
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K

130 THE NERVOUS SYSTEM.

Maddox, On the apparent relation of Nerve to Connective-tissue Corpuscles.
Monthly Microse. Journ. Vol. IX, p. 109.

Maier, R., Die Ganglien in den harnabfiihrenden Wegen des Menschen und einiger
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Marchi, P., Beobachtungen iiber Wimper-Epithel. Arch. f. mik. Anat. 1866. Vol.
II, p. 467.

Marshall, A. M., The segmental value of the Cranial Nerves. Journ. of Anat. and
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Marshall, A. M., The Frog: an introduction to Anatomy and Physiology. Man-

chester and London, 1885.

Masius and Vaulair, De la situation et de ’étendue des centres réflexes de la
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Mason, J.J., A new group of Nerve-cells in the Spinal Cord of the Frog. New York
Med. Journ. 1879.

Mason, J. J., Microscopic Studies on the Central Nervous System of Reptiles and
Batrachia. Journ. of Nerv. and Mental Diseases. New York. 1880, Vol.
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Mason, J. J., Minute Structure of the Central Nervous System of certain Reptiles
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Mayer, A. F. J. C., Ueber das Gehirn der Amphibien und ein zoologisches Gesetz.
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Mayer, 8., Zur Lehre der Struktur der Spinalyanglien und der peripherischen
Nerven in Rana esculenta. Arch. f, Anat. u. Physiol. 1858, p. 274.

Mays, K., Histo-physiol. Untersuchungen iiber die Verbreitung der Nerven in den
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Mays, K., Ueber die Nervatur.des Musculus rectus abdominis des Frosches. Hei-
delberg, 1886. :

Mays, K., Nervenfasertheilungen in den Nervenstiimmen der’ Froschmuskeln.
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Meckel, A., System der vergleichenden Anatomie. Halle, 1833.

Meckel, J. F., Beitriige zur vergleichenden Anatomie. Leipzig, 1811.

Michel, Ueber den Bau des chiasma nervorum opticum. vy. Grife’s Arch. 1864.
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Miller, J., Beitrige zur Anatomie und Naturgeschichte der Amphibien. Tiede-
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Namias, M., Sui ganglii miocardici della Rana. Osservazioni ed esperienze in Lo
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Niccolucci, G., Sul sistema nervoso e circolatorio della Salamandra aquaivola.
Napoli, 1842.

Niura, M., Untersuchungen tiber die motorischen Nervenendigungen der querge-
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Obersteiner, Ueber einige Lymphriiume im Gehirne. Wiener Sitzungsber. 1870,
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Odenias, M. W., Undersékungar éfver de sensibla muskelnervena. Nord. Medic.
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Onodi, A. D., Ueber die Entwicklung des sympathischen Nervensystems. Arch. f.
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Onodi, A. D., Ueber die Gangliengruppen der hinteren u. vorderen Nervenwurzeln.
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v. Openchowski, Th., Beitrag zur Kenntniss d. Nervenendigungen im Herzen.
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v. Openchowski, Th., Histologisches zur Innervation der Driisen. Pfliiger’s Arch.
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Osborne, H. F., Observations upon the Urodele Amphibian Brain. Zool. Anz.
1884. Vol. VII, p. 679.

LITERATURE. 131

Osborne, H. F., Observations on the presence of the corpus callosum in the brains
of Amphibians and Reptiles. Zool. Anz. 1886. Vol. IX, p. 200.

Osborne, H. F., Note upon the cerebral commissures in the lower vertebrata and a
probable fornix rudiment in the brain of Tropidonotus. Zool. Anz. 1886. Vol.
IX, p. 577-

Partsch, C., Beitrige zur Kenntniss des Vorderdarmes einiger Amphibien und
Reptilien. Arch. f. mik. Anat. 1877. Vol. XIV, p. 179.

Pertik, O., Untersuchungen iiber Nervenfasern. Arch. f. mik. Anat. 1881. Vol.
XIX, p. 183.

Pfitzner, Nervenendigungen im Epithel. Morph. Jahrb. 1882. Vol. VII, pp.
726-745.

Popoff, N., Die Nerven der Gallenblase. Rudneff’s Journ. f. normale und pathol.
Histologie u. klin. Med. St. Petersburg, 1872. (In Russian. Abstract in
Virchow and Hirschfeld’s Arch.)

Priestley, J., An account of the anatomy and physiology of the batrachian lymph-
hearts. Journ. of Physiol. 1878. Vol. I, p. 1.

Ranvier, L., Recherches sur lhistologie et la physiologie des nerfs. Arch. de
physiol. normale et pathologique. 1872. Vol. IV, pp. 427-446.

Ranvier, L., Appareil nerveux terminaux des muscles de la vie organique. Legons
d’anat. générale. Paris, 1880, p. 350.

Ranvier, L., Des tubes nerveux en T et de leurs relations avec les cellules gang-
lionaires. Compt. rend. 1875. Vol. LX XXTI, p. 1274.

Ranvier, L., Lecons sur Vhistologie du systtme nerveux. 1878. Vol. 1, pp. 98—1o!.

Rawitz, B., Ueber die Structur der Zellen in den Spinalganglien, ete. Arch. f.
mik. Anat. 1880. Vol. XVIII, p. 283.

Rawitz, B., Ueber den Bau der Spinalganglien. Arch. f. mik. Anat. 1880. Vol.
XVIII, p. 283.

Rawitz, B., Ueber den Bau der Spinalganglien. Arch. f. mik. Anat. 1882. Vol.
XXI, p. 244.

Reichert, K. E., Ueber das Verhalten der Nervfasern bei dem Verlauf der Ver-
theilung und Endigung in einem Hautmuskel des Frosches, Rana temporaria.
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Reissner, E., Der Bau des centralen Nervensystems der ungeschwiinzten Batra-
chier. Dorpat, 1864.

Remak, R., Anatomische Beobachtungen iiber das Gehirn, das Rickenmark und die
Nervenwurzel. Arch. f. Anat. u. Physiol. 1841, pp. 506-522.

Remak, R., Multipolare Ganglienzellen. Berliner Monatsberichte. 1854, p. 26.

Retzius, G., Undersékung éson cerebrospinalganglionus nervseller and sirskild
hiiusyn till dessus ut lépare. Nord. Med. Arkiv. 1879.

Retzius, G., Untersuchungen iiber die Nervenzellen der cerebrospinalen Ganglien,
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Reynier, Les nerfs du ceur. Paris, 1880 (pp. 32-37, ganglia of heart).

Rosenberger, De centris motuum cordis disquisitiones anatomico-pathologicae.
Inaug. Diss. Dorpat, 1850.

Rouget, Note sur la terminaison des nerfs moteurs dans les muscles chez les
reptiles, les oiseaux et les mammiftres. Compt. rend. 1862. Vol. LV, pp.
548-555-

Rumph, T., Zur Histologie der Nervenfaser und des Axencylinders. W. Ktihne’s
Heidelberger Untersuchungen. 1879. Vol. II, p. 355.

Sachs, C., Die Nerven der Sehnen. Reichert u. du Bois-Reymond’s Arch. 1875,
p- 402.

Boni J., Die Spinalfasern im Sympathicus des Frosches. Arch. f. Anat. u. Physiol.
1866, p. 398.

Sanders, A., Contributions to the Anatomy of the Central Nervous System in
Vertebrate Animals. Phil. Trans. 1882. Pt. III, p. 927.

K2

132 THE NERVOUS SYSTEM.

Scheel, Ueber die Kreuzung der Sehnerven im Chiasma bei den Wirbelthieren u.
beim Menschen. Klin. Monatsbl. f. Augenheilk. Vol. XII.

Scherhej, M. L., Zur Lehre der Innervation der Lymphherzen. Arch. f. Anat. u.
Physiol. 1879. Physiol. Abth., p. 227.

Scherkey, M. L., Ueber die Feststellung und Bedeutung der Centren-der Lymph-
herzen im Riickenmark. Dissert. Berlin, 1878. Abstract in Centralbl. f. d. med.
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Schiefferdecker, P., Beitriige zur Kenntniss des Baus der Nervenfasern. Arch. f.
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Schiess, Versuch einer speciellen Neurologie der Rana esculenta. St. Gallen und
Bern, 1857.

Schmidt, M., Beitriige zur Kenntniss des Riickenmarkes der Amphibien. Zeit. f.
Naturwiss. Vol. IV, pp. 1-45.

Schmidt, M., Beitriige zur Kenntniss des Riickenmarkes der Amphibien. Zeit. f.

- Naturwiss. Vol. LVIII, pp. 1-44.

Schébl, J., Ueber die Blutgefiisse des cerebrospinalen Nervensystems der Urodelen.
Arch. f. mikrosk. Anat. 1882. Vol. XX, p. 87.

Schoébl, J., Ueber Wundernetze und divertikelbildende Capillaren bei nackten
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Schénn, Ueber das angebliche Epithel des Riickenmarks und Centralcanals.
Stettin, 1865.

Schénn, Ueber die Entwicklung des Riickenmarks. Stettin, 1865.

Schramm, Neuve Untersuchungen tiber den Bau der Spinalganglien. Diss. Wirzburg,
1864.

Schulgin, M. A., Lobi optici der Vogel; vergl. anat. Studien. Zool. Anz. 1885.
Nos. 84 and 85. :

Schultze, H., Axencylinder und Ganglienzelle. Reichert u. du Bois-Reymond’s
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Schwalbe, G., Bemerkungen iiber die Kerne der Ganglienzellen. Jenaische
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Schwalbe, G., Ueber den Bau der Spinalganglien nebst Bemerkungen iiber die
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Schwalbe, G., Lehrbuch der Anatomie der Sinnesorgane. Erlangen, 1885.

Schwalbe, G., Das Ganglion oculomotorii. Jenaische Zeitsch. f. Naturwissensch.
1879. Vol. XIII, p. 173.

Schwalbe, G., Handbuch der Neurologie. Erlangen, 1881.

Schweiger-Seidel, Das Herz. Stricker’s Gewebelehre, p.177. (Ganglion cells of
heart.)

Serres, C., Anatomie comparée du cerveau des quatres classes des animaux vertébrés.
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Sokoloff, A. A., Ueber die Nervenendigungen in den Muskeln ausgehungerter
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Sokolow, Sur les transformations des terminaisons des nerfs dans les muscles de la
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Solly, 8., The Brain. London, 1837.

Sommé, C. L., Recherches sur l’anatomie comparée du cerveau. Anvers, chez
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Spencer, W. B., On the presence and structure of the parietal eye in Lacertilia.
Quart. Journ. Micros. Sci. 1886. Vol. XX VII, p. 165.

Spina, A., Untersuchungen des lebenden Bindegewebes. Oecsterr. med. Jahrb.
1885.

Stannius, Lehrbuch der vergleichenden Anatomie der Wirbelthiere. Berlin, 1856.

Stannius, Handbuch der Zootomie, 2nd Edit., 1856. Berlin. And Miiller’s Arch.
1852, p. 85.

LITERATURE. 138

Stannius, Handb. der Anatomie der Wirbelthiere. 2nd Edit., 1854.

Stieda, L., Studien tiber das centrale Nervensystem der Wirbelthiere. Zeitschr. f.
wiss. Zool. 1870. Vol. XX, p. 273.

Stieda, L., Zur vergleichenden Anatomie und Histologie des Cerebellum. Reichert
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Stirling, W., On the Nerves of the Lungs of the Newt. Journ. of Anat. and
Physiol. 1882, p. 96.

Stirling, W., and Macdonald, F., The minute structure of the palatine nerves of
the frog and the termination of nerves in blood vessels and glands. Journ. of
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Swan, Illustrations of the Comparative Anatomy of the Nervous System. London.

v. Thanhoffer, L., Neuer Nervenapparat im Diinndarm. Centralb. f. d. med.
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v. Thanhoffer, L., A csigolyakézti diczsejtek szerkezet¢hez. Ertekezések 4 termé-
exettudoményok k6rébél. Kiadja a. m. t. Akadémia. 1877.

Tiedemann, Anatomie und Bildungsgeschichte des Hirns. 1816.

Toel, G. H., Die Ranvierschen Schniirringe markhaltiger Nervenfasern und ihr
Verhialtniss zu den Neurilemmkernen. Dissert. Ziirich, 1875.

Toloschinoff, Ueber das Verhalten der Nerven zu den glatten Muskelfasern der
Froschharnblase. Arch. f. mik. Anat. 1869. Vol. V, p. 509; and in Stricker’s
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Tordk, A., Beitrige zur Kenntniss der ersten Anlagen der Sinnesorgane und der

Schadelformation bei den Batrachiern. Wiener Sitzungsber. 1886.
Vol. LII, Pt. I, p. 646.

Traugott, Ein Beitrag zur feineren Anatomie des Riickenmarks von Rana tempo-
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Treviranus, G. R., Untersuchungen iiber den Bau und die Functionen des Gehirns.
1820.

Treviranus, G. R., Ueber die hinteren Hemisphaeren des Gehirns der Vogel, Am-
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and Leipzig, 1831. Vol. IV, p. 39.

Treviranus, G. R., Bemerkungen iiber das Nervensystem des Fisches und iiber
einige bisher unbeachtete Theile dieses Thieres in G. R. and L. Chr. Treviranus.
Verm. Schriften Anat. u. Physiol. Vol. I, 1816, p. 94.

Tschiriew, S., Sur les terminaisons nerveuses dans les muscles striés. Arch. de
physiol. norm. et pathol. 1879. Vol. VI, 2 sér., p. 89.

Valentin, Die letzten Enden der Nerven. Nova acta academ. caesar. -Leop. 1836.
Vol. XVIII, p. 51.

Vignal, Recherches sur V’appareil ganglionaire du cceur des vertébrés. Labora-
toire d’histologie du Collége de France. Travaux de l'année 1881, p. 186. Also
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Vogt, C., Beitriige zur Neurologie der Reptilien. Neuchatel, 1840.

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134 THE NERVOUS SYSTEM.

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THE NERVOUS SYSTEM.

—_>——_

I THE CENTRAL NERVOUS SYSTEM.
(Re-written by the translator.)

A. Tue Spryat Corp (Fig. 97).

1. External form. The spinal cord is, in comparison with the
brain, somewhat small; the two organs are directly continuous,
and present no distinct line of demarcation: the point of origin
of the first spinal nerve is, therefore, arbitrarily accepted as the
anterior limit of the spinal cord ; posteriorly it terminates in the
jitum terminale.

The spinal cord is flattened dorso-ventrally, and is constricted
at a point (yars media, Reissner) somewhat anterior to its
middle: in consequence of this constriction the cord has two
enlargements; an anterior smaller, and a posterior larger (zxtu-
mescentiae anterior v. posterior), from which arise the nerves of the

_ brachial and lumbar plexuses respectively. At about the sixth
‘o seventh vertebra, the hinder enlargement diminishes rather
abruptly to form the so-called conus medullaris ; this is continued
into the jfilum terminale, which enters the cavity of the urostyle.
The hinder portion of the lumbar nerves forms a cauda equina,
the constituent nerves of which surround the ji/um termina/e.

A dorsal longitudinal fissure (su/cus longitudinalis superior) is
well marked in the middle line of the dorsal surface of the pos-
terior enlargement ; anteriorly and posteriorly it rapidly fades away,
its position being merely indicated by a small amount of connective-
tissue and a blood-vessel.

The ventral longitudinal fissure (su/cus longitudinalis inferior) is
well marked throughout the length of the cord. Neither fissure can
be traced in the hinder part of the conus medullaris or in the filum

Ten pairs of nerves arise from the spinal cord, each nerve arising
by two roots, a ventral and a dorsal (anterior and posterior), from

136

THE NERVOUS SYSTEM.

points near the ventral and dorsal longitudinal sinuses respec-

ively ;, the two roots unite their point
} x » © y @ x : Soe

Fig. 97.

.

Ma.

am |

of exit from the ver-
tebral canal through
the intervertebral for-
amen ; each dorsal root
possesses a ganglion.

The nervous system of Rana es-

_ culenta, from the ventral sur-
face. (From Icones physiolo-
gicae by A. Ecker. Pl. XXIV,
Fig. 1.)

F Facial nerve.

G Ganglion of pneumogas-
tric nerve. mit

He — Cerebral hemisphere.

Ie Optic tract,

Lop Optic lobe.

M. Boundary between me-
dulla oblongata and spi-
nal cord. | ~

vu. t—10 Spinal nerves.

MS Connection between fourth
spinal nerve and sympa-
thetic chain,

N ° Nasalsac,

/Ni Sciatic nerve.

No Crural nerve,

7) Eyeball,

JS Trunk of sympathetic.

/S81—10 Sympathetic ganglia.

Sm Rami communicantes of

sympathetic,
Sp Continuation of sympa-
thetic into head,
ED 4 Olfactory nerve. ~

iI Optic.nerve,
III Motor oculi nerve,
IV _Trochlear nerve,

V Trigeminal and facial
nerves,

Va Ramus ophthalmicus of
trigeminal. -

Ve Ramus maxillo-mandibu-
laris of trigeminal.

Vad Mandibular branch of
trigeminal.

Ve Hyomandibular branch of
facial, 3

Vg _ Gasserian ganglion,

Vs Upper end of sympathetic *
trunk in connection with
Gasserian ganglion,

VI Abducens nerve,

VII Facial nerve.

VIII Auditory nerve,

xX Glossopharyngeal, and
pnheumogastric nerves,

Xz Ramus anterior of glosso-

pharyngeal.

X2 Ramus posterior of glosso-
pharyngeal.

X3—4 Branches of pneumogas-
tric. wae

———— ee Oe. ee

ee ee ee

THE SPINAL CORD. 137

2. Internal structure. As in other vertebrates, the spinal cord
consists o£ white and grey matter, the latter being surrounded by
the former ; the relative amount of the one to the other varies in
different parts of the cord.

A transverse section of the cord presents the same general
characteristics as a similar section from a bird or mammal. The
grey matter lies in the middle, surrounding the central canal, and is
prolonged into each half of the section by ventral and dorsal horns
or cornua. The grey matter is surrounded by the white, but is
not so sharply marked off from this in amphibia as in birds and
mammals.

A section through the anterior enlargement is almost quad-
rangular in outline, and somewhat broader below than above; the
ventral longitudinal fissure is well marked and deep, while the
dorsal is indistinct. The dorsal horns are narrow and short, the
ventral longer and much broader. The space between the dorsal
horns is narrow and deep, that between the ventral shallow; the

ee

- outer boundary of the grey matter is almost straight, and the central

canal is placed above the centre of the section.

In the constricted portion of the cord (pars media) the relative pres
portion of the white matter is increased at the expense of the grey;
the horns are less distinct, the dorsal being directed outwards and
the ventral somewhat flattened. The central canal is in the centre
of the section.

The posterior enlargement shows the ventral horns projecting out-
wards, very much enlarged, and approaching the periphery; the space —

. between them is semilunar. The dorsal horns are well developed,

especially at their upper parts 5 the space between them is narrow
and deep. The outer margin of the grey matter is again nearly a
straight line. The central canal is below the centre of the section.

The arrangement of the parts in the conus medullaris approaches
that in the pars media: the horns are much diminished in size, and
posteriorly they entirely disappear, the ventral horns persisting longer
than the dorsal. The central canal approaches the lower surface.

No cornua can be recognised in the jilwm terminale behind the
origin of the last pair of spinal nerves. The grey matter has here
a circular outline, with the exception of a very slight indentation
below ; the white matter is almost absent: the central canal is on
the lowes border of the section in the anterior part, while posteriorly
it occupies almost the entire space below the pia mater.

The Central Canal lies in the median line, and always presents a _

138 THE NERVOUS SYSTEM.

distinct lumen; in the two enlargements this lumen forms a vertical
ellipse ', while in the pars media it is circular. The canal is lined by
a single layer of ciliated columnar epithelium, the cells of which
are usually conical, with their bases directed towards the lumen ; but
other forms may be noticed. These cells average about 0040 mm.
in length and about o:002 mm. in width at their broadest part.
The peripheral extremities of the cells have processes, which, in the
ease of the cells above and below the cord, may often be traced
as far as the pia mater; the processes of the lateral cells are less
distinct and seem to be shorter. Anteriorly the central canal
opens into the floor of the fourth ventricle. The termination of
the central canal, posteriorly, has been described by Masius
and Vanlair. According to these observers, the canal towards the
hinder end of the fidwm terminale increases very gradually in width,
until its epithelial cells are immediately underneath the pia mater,
its walls then converge somewhat more sharply to close the cavity.
From the point where the canal commences to increase in width,
a change takes place in its epithelial wall, which, instead of having
a single layer of cells, now possesses two to three layers; towards
the posterior end it is again thinned out to a single layer.

The grey matter varies in different parts of the cord and in dif-
ferent parts of the same section. In a section through the anterior
enlargement a portion of the grey matter, placed immediately above
the central canal, is easily distinguished by its vertically-placed,
elliptical outline, and by its transparency: it is known as the swd- -
stantia reticularis. It consists of a mesh-work of branched cells,
through which course distinctly contoured fine commisural fibres
which are derived chiefly from the dorsal cornua, the vertical
from the epithelial cells of the roof of the central canal. In a
seriés of sections the substantia reticulosa may be seen to originate
indistinctly in the most anterior part of the cord; in the anterior
enlargement it already possesses the elliptical form mentioned, and
in the pars media it commences to send off lateral processes to either
side. In the posterior enlargement it reaches its greatest absolute
development, as it here surrounds the central canal; while further
‘backwards it engroaches until, together with the remaining grey
matter, it constitutes almost the whole of the ji/um terminale.

Immediately underneath the central canal is a narrow band,
which immediately connects the grey matter of the two sides ;
above it is bounded by the epithelium of the central canal, below

1 y, Kolliker states that the lumen is everywhere circular.

THE SPINAL CORD. 139

by medullated fibres. This septum medium (Reissner) may be traced
backwards from the anterior extremity of the cord to the posterior
enlargement. It consists chiefly of transverse fibres, together with
vertical fibres derived from the epithelial cells on the floor of the
canal, and like the sudstantia reticulosa, is distinguished by its
greater transparency from the rest of the grey matter.

The grey matter consists of connective-tissue and nervous ele-
- ments, which are very intimately united; each of these elements
including its special cells and fibres. The nerve-cells vary much in
size and appearance. A prominent group of large cells in the ven-
tral cornua, the lateral group (Stieda), is very conspicuous. The
individual cells are seldom rounded, but are usually spindle-shaped
or angular, and each possesses one to five processes, which may
often be traced through considerable distances. These cells have an
average length of o-o40 mm., and are about o’016 mm. broad;
they are somewhat larger in the anterior enlargement than in the
posterior, and are also more numerous in a section from the anterior
enlargement than in a section from the posterior. In the terminal
filament they gradually disappear. Some of their processes are
continued into the lateral columns (K6ppen).

Smaller, spindle-shaped or triangular cells are scattered irregu-
larly throughout the grey matter, without forming distinct groups,
though for descriptive purposes those of the centre have been named
the central group: In a stained, transverse section of the cord are
seen numerous nuclei; these undoubtedly belong both to small
nerve-cells and to connective-tissue cells, but except under the most
favourable conditions the two are indistinguishable. The larger
nerve-cells present the usual characters of nerve-cells : more or less
granular contents, nucleus, well-marked nucleolus, more or less
marked fibrillation ; their processes are usually more homogeneous.
The cells are frequently pigmented.

The processes of the cells belonging to the lateral group radiate
in all possible directions, but certain well-marked processes directed
towards the middle line can always be made out. From the lowest
part of this group a few processes may be traced into the ventral
roots. The small cells seem to be chiefly arranged vertically, al-
though their processes radiate in all direttions (Stieda).

The Fibres of the grey substance are nearly all non-medullated.
They may be traced in all‘directions, but the best-marked groups
are either vertical or transverse. The vertical fibres appear to arise
from the central grey matter, and to ascend in larger or smaller

140 THE NERVOUS SYSTEM.

bundles towards the periphery. The transverse fibres are arranged
chiefly in the two commissures: the dorsal commissure (commissura
superior) is the smaller; the fibres are parallel, and show no trace
of decussation ; externally they radiate in various directions to the
dorsal horns. ‘The ventral commissure is composed of two layers, the
upper grey (commissura inferior grisea), the lower white (commissura
inferior alba): both are interrupted by the septum medium. A well-
marked decussation of the fibres is seen in the middle line ; the exact
mode of termination of these fibres has not been made out, but many
appear to communicate with the large cells of the ventral horns.

The white matter consists chiefly of longitudinal, medullated
fibres, in which various columns may be distinguished. The dorsal
columns are separated from the lateral by a process of neuroglia,
~ continued from the general investment of neuroglia lying under the
pia mater. The line of separation between the lateral and ventral
columns is not well marked ; it is about the line which would be
formed by prolonging the ventral horns to the surface.

The fibres vary in size, and fibres of all sizes may be found
in any particular part of a transverse section ; still the fibres of the
ventral columns have an average greater diameter than those of
the lateral columns, and the fibres of the dorsal columns are finer
than those of the lateral. The largest fibres of the ventral column
are placed near the ventral fissure and on its lower border; they
attain their greatest development in the posterior enlargement ;
these fibres frequently contain two or three axis-cylinders each.
K6ppen suggests that they may represent the formatio reticularis of
higher animals.

In the lateral columns the larger fibres are placed close to the .
grey matter, these columns also receive fibres from the cells of the
lateral group. : 3

In the dorsal columns the radiating root-fibres “never reach the
median plane, but leave an area of baadly longitudinal fibres on. each
side of the dorsal fissure ; these represent Goll’s columns, and have
a club-shaped outline in transverse section.

The white matter is pierced in all directions by fine connective-
tissue fibres and bundles of fibres which radiate from the grey matter;
some branch and join with others to form a network, others pass
almost uninterruptedly to the periphery. From the connective-tissue
cells of the pia mater, processes pass into'the white matter and assist
in completing the connective-tissue matrix for the nervous elements.

Dorsal roots of the spinal nerves. Each root consists of a

THE BRAIN. 141

single bundle of nerve fibres, which suddenly bends at the periphery
of the cord in order to descend vertically through the white matter
towards the dorsal horn; the fibres divide into three sets, one to
the dorsal commissure, a second to the upper horn itself, and the
third helps to form the dorsal columns.

Ventral roots of the spinal nerves. Each ventral root consists
of three or four delicate threads, which may be traced to the ven-
tral cornua, which they reach after a vertical or very slightly
oblique course through the white matter. Other fibres arise from
the ventral columns, but these oblique fibres never extend to the
median plane.

Pigment is found distributed irregularly through a section from
any part of the spinal cord ; it is creased in amount in those parts
in which there is an increased amount of grey matter. The pigmen-
tation is always found more marked in the lower parts of the
ventral horns than in other parts.

B. Tue Bratn (Figs. 98, 102, 103, and 105).

1. General description. From behind forwards, the dorsal
surface of the brain presents the following parts for examination :
the medulla oblongata, the cerebellum, the optic lobes, the thalamen-
cephalon,, the cerebral hemispheres, and the olfactory lobes.

The medulla oblongata is a direct continuation of the spinal cord ; it
is wider anteriorly than posteriorly, and is separated in front from the
optic lobes by a vertical plate of nervous matter, the cerebellum. The
optic lobes are two symmetrical ovoid bodies touching each other in
the median plane, and tegether forming the widest part of the brain.
In front of the optic lobes is the thalamencephalon, with a thick
vascular membrane, the choroid plexus, lying on its upper surface,
and connected with the pineal gland; the thalamencephalon extends
forwards between the posterior ends of the cerebral hemispheres. _
The cerebral hemispheres are two symmetrical ovoid bodies, narrow ~
in front, wider and slightly diverging behind: each hemisphere is
prolonged forwards to form an olfactory lobe.

The ventral surface has in front the olfactory lobes, then the
cerebral hemispheres, behind these the /amina terminalis, the tuber
cinereum, the optie chiasma, the pituitary body, the crura cerebri,
and lastly the medulla oblongata, in the order here given.

The various cranial nerves (Figs. 102 and. 103) may be seen to
arise as follows:—The olfactory nerve (J, I’, L.ol’) arises directly

7 Try eS ee a

ta2\- ; THE NERVOUS SYSTEM.

from the anterior end and outer side of the corresponding olfactory
lobe, and from the cerebral hemisphere. The optic nerve (Zo and
IT) arises, as the optic tract, from the side of the brain below the
optic lobe, whence it passes to the chiasma on the under surface of
the brain. The oculo-motor (Z//) takes its origin from the ventral
surface close to the median line and between the erura cerebri.
The pathetic or trochlear nerve (JV) is attached to the dorsal
surface between the optic lobes and the cerebellum. The trige-
minal nerve (/) arises from the side and anterior part of the
medulla oblongata. The abducens (V1) arises behind the pituitary
body close to the median line from the ventral surface of the
medulla halfway between the swdeus and the origin of the vagus.
The facial and auditory (VJZ and VIII) nerves arise from the
medulla oblongata behind the trigeminal nerve, the facial -beng
in front of the auditory nerve. The glossopharyngeal (ZX) nerve
arises, in common with the pneumogastric nerve (X), behind the
auditory nerve.

2. The several parts of the brain. _

a. The medulla oblongata (Figs. 98, 102, and 103 Mo)—a. External
form. The meduila is limited behind by the origin of the first pair
of spinal nerves, at which point a very faint constriction is sometimes
found : it extends forwards as far as the cerebellum. It gradually
widens as it passes forwards until just before it reaches its anterior
limit, where it presents a shallow but sharp constriction. The
dorsal surface is characterised by the presence of a deep, triangular
fossa, the fourth ventricle (Fig. 98 Sr), esti quartus,
Stieda; sinus rhomboideus s. sinus triangularis, Reissner; fossa
rhomboidalis); the sides of the triangle are, however, it quite
straight, but are slightly bent outwards just before they converge
towards the posteriorly-directed apex; the base of the triangle _
is formed by the cerebellum. By careful examination, the ventricle
is seen to be continued for a short distance under the cerebellum,
where it opens into the Sylvian aqueduct. In the floor of the fourth
ventricle is a well-marked median longitudinal fissure (swdeus cen-
tralis), (Fig. 98 8). Into the posterior part of the ventricle opens the
central canal of the spinal cord. As the fourth ventricle is formed
by the white matter passing to either side, and the simultaneous
flattening of the grey matter, the floor of the fourth ventricle is
composed of grey matter.

The fourth ventricle is closed in by a highly vascular mem-
brane, the choroid plexus of the fourth ventricle (plexus cho-

THE MEDULLA OBLONGATA.

143

roideus ventriculi quarti, Reissner; velum medudlare posterius). The
blood-vessels of the plexus will be described together with the

other vessels of the brain (p. 162). They
are supported by a connective-tissue matrix,
and the whole covered with flattened epi-
thelium, which in the fourth ventricle is
ciliated and often pigmented.

The ventral surface of the medulla ob-
longata (Fig. 102 Mo) has a median ventral
longitudinal fissure, | a direct continuation of
that of the cord; in the anterior part of the
medulla siidigite there is also to either side
of this a lateral fissure, continued on to the
erura cerebri; these fissures correspond to
the positions of the two rami posteriores of
the internal carotid arteries ; they are always
well seen in microscopical sections. The

_ medulla oblongata is so intimately connected

with the pars commissuralis (pp. 149, 150)
that the minute anatomy of the two is best
deseribed at the same time.

8. Internal structure. Examined by
means of serial sections, the medulla oblon-
gata is seen to have, in comparison with the
cord, an increased amount of grey matter ;
this is especially the case in its anterior part.
The floor and inner parts of the walls of
the ventricle are formed of grey matter, in
which the largest-sized cells have disap-

- peared, to be replaced by medium-sized
horns of the cord are seen to increase in
size and to be more widely separated until

Traced from behind, the ventral

they form two isolated masses, while the
dorsal horns. gradually diminish; at the

Dorsal view of brain of Rana
esculenta,

Ad Choroid plexus, m1

C Cerebellum.

Jf Groove between cerebral
hemispheres and elfactery
lebes.

G @pening in the roof of the
third ventricle.

Gp Pineal body.

He Cerebral hemispheres.

I Olfactory nerve.

“Li Wall of fourth ventricle.

L.ol Olfactory lobe.

L.op Optic lobe.

Mo Medulla oblongata.

s Longitudinal fissure of the
fourth ventricle.

S.r Fourth ventricle.

Tho Thalamencephalon,

same time they are forced outwards and upwards, until they lie under
the floor of the ventricle, and so extend to the pars peduncularis.
Grey matter. The sudstantia reticularis is not present, but the
septum medium extends forwards as far as the pars peduncularis.
The central canal extends upwards at the expense of the tissue
above it, and is here pespbeped; ; at the same time the dorsal

144 THE NERVOUS SYSTEM.

‘longitudinal fissure deepens until the two meet in the fourth ven-
tricle; beyond this point one cannot speak of dorsal and ventral

horns.
Small nerve cells are irre-

gularly distributed through-
out the whole of the grey
matter and cannot be
grouped; the larger cells,
on the other hand, are
arranged in distinct groups
which have special relations
with the nerves arising
from the part. Occasion-
ally these groups are not
so isolated as usual; in
this case processes of one
group can be traced into
another group (Reissner).
Of these groups the chief

Transverse section through hinder end of Medulla are:
oblongata (magnified 30-80)1, from Stieda. zi

b Inferior commissure. 1. The nucleus centralis -
Ff Dorsal horns, S :

> Wenteal horrid (upper inner group, Reiss-
h Fourth ventricle, ner), nucleus medullae oblon-

z~ Nucleus centralis, . 3 RE
k Isolated mass of grey matter in which longitudinal gatae, Stieda (Fig. 99 7), is

fibres of the pneumogastric nerve course. a group, of cells foun d to-
wards the hinder end of the medud/a oblongata, on either side of and
below the central canal; the group can be traced under the floor of
the fourth ventricle to about its middle. The cells are rounded or
spindle-shaped, the processes directed upwards, downwards, or out-
wards ; their average size is 0'040-0'048 mm. long by 07020 mm.
broad. ;

2. The auditory nucleus (nucleus acusticus, Reissner, Stieda),
(Fig. 100 2) is a large group of cells found in the wall of the
fourth ventricle opposite the poimt of origin of the auditory nerve,
The cells are rounded, pear-shaped, or of spindle form, and inter-
spersed between the nerve fibres; these cells have an average
length of o'o40 mm., and are about half as broad. The fibres
of the auditory nerve radiate from their superficial origin in all

1 In these diagrams, from Ludwig Stieda’s Studien tiber das centrale Nervensystem

der Wirbelthiere, the outline of the diagram is magnified thirty times, while the
details are magnified eighty times.

THE MEDULLA OBLONGATA. 145

directions through the grey matter towards these cells, and evidently
communicate with them (Fig. 101 p). One small group (Fig. 101 7)
passes to a lower level than the rest, and is regarded by Stieda as

Fig. 100.

Transverse section through the Meduila oblongata at the point of origin of the abducens nerve,
from Stieda. Magnified 30x 80.)

Ah =©Fourth ventricle,
m Abducens nerve.
n Anditory riucleus.
o Abducens nucleus.

the true auditory centre. Képpen considers that the auditory nerve
has a threefold origin: (1) from small cells on the median surface
of the auditory area; (2) from the large cells between the above ;
(3) from a group of free nuclei on the dorsal surface of the auditory
area.

3. The trigeminal nucleus (nucleus trigeminus), (Fig. 101 g)
lies in part beneath the auditory nucleus but extends further
forwards. It forms a rounded group of cells placed under the outer
angle of the grey matter. The cells are somewhat crowded together,
and are chiefly of an elongated spindle-form, with their processes
directed obliquely downwards and outwards. The fibres of the trige-
minal nerve separate into two groups ; the upper group is best traced
in a horizontal section, the fibres curving round to join the longitu-
dinal fibres continued from the dorsal columns of the cord. The
fibres of the lower, smaller group pass transversely inwards to the

L

>

146 THE NERVOUS SYSTEM,

trigeminal nucleus. According to Reissner the latter fibres are
motor, the former sensory. Probably other nerves are connected
with the hinder part of this group.

4. The abducens nucleus (Fig. 100 0). From its superficial
origin, the fibres of the abducens nerve may be traced vertically
upwards to a small, rounded, grey mass; at this point the mass
is somewhat isolated, but further forwards it may be traced
pe aa to the central grey matter ; it contains small spindle
cells.

Fig. 101.

Transverse section of the Meduila oblongata, at the point of origin of the auditory nerve, from
Stieda, (Magnified 30x 80.)

Fourth ventricle.

Auditory nucleus,

Abducens nucleus.

Auditory nerve.

Ganglion of auditory nerve.

Hinder portion of trigeminal nerve.

Bundle of fibres arising from trigeminal nucleus and joining the auditory nerve.

~

SAVesose

5. The pneumogastric nucleus. The pneumogastric, with its
numerous irregular roots, arises from the side of the medulla ob-
longata. The hindermost fibres can be traced as a small bundle,
passing almost transversely through the white matter to the outer
margin of the grey matter. The larger portion of the fibres is
placed in front of these; part of this seems to be directly con-
tinuous wath the longitudinal fibres of the white matter; a
-second part, however, can be traced from the surface transversely

THE MEDULLA OBLONGATA. 147

through the white matter to the grey matter. These latter fibres,
together with those of the group first described, do not arise from
the grey matter in this part of the medulla oblongata, but curve
round and run backwards longitudinally through the grey matter,
thus forming a rounded bundle of fibres (Fig. 99 4). Between these
fibres are interspersed small nerve-cells and nuclei which disappear
as the fibres approach the white matter. The vagus undoubtedly
receives fibres from the grey matter throughout a long course,
and again receives a large bundle just before leaving the grey
matter. The more exact origin of the various fibres has not been
traced.

6. The nucleus magnus (Reissner and Stieda) is a very peculiar
group of cells placed on either side, in the most anterior portion of
the pars commissuralis, that is, immediately underneath the valvula
cerebelli. The large cells are arranged in a transverse section in a
- single row so as to enclose a pear-shaped space on either side, which
has its long axis directed from above, downwards and outwards, the
narrower end being above. In longitudinal section the line of cells
is seen to be open m front. The space enclosed by these cells is
occupied by a granular ground-substance which contains only few
nuclei. Bellonci is of opinion that these nuclei represent the corpora
quadrigemina posteriora of higher animals.

White matter. In the hinder part of the medulla oblongata the
arrangement of the white matter resembles that of the white
matter of the spinal cord; further forwards the white matter of
the dorsal surface commences to pass to either side, and ultimately
it forms the outer part of the walls of the fourth ventricle. The
fibres of the white matter of the ventral surface are unchanged in
direction as they proceed forwards. The fibres of the anterior part
of the medulla are thinner than those of the posterior portion
(Stieda), according to Reissner they gradually thin as they pass
forwards. The fibres are nearly all longitudinal, such transverse
and oblique fibres as are present being chiefly in connection with
the various nerve-roots and the commissures.

The commissura superior is naturally lost in consequence of the
opening of the central canal into the fourth ventricle; the com-
missura inferior is increased in the anterior half and decreased in
the posterior half of the medulla oblongata; in the latter the
fibres become more and more oblique, and decussate very freely ;
ultimately they seem to be either continued as longitudinal fibres or
to join the ganglia.

L2

148 THE NERVOUS SYSTEM.

Near the pars commissuralis is a transverse arched band of fibres,
passing from the under surface of one half of the cord over the
ventral longitudinal fissure through the septwm medium to the under
surface of the opposite half; part of the fibres are continued up-
wards along the periphery to the cerebellum, part to the nucleus
magnus. Vertical, straight, or slightly arched fibres are found in
the walls of the fourth ventricle.

A section from the medulla oblongata has a larger amount of
pigment than a section from the spinal cord, and the anterior portion
of the medulla oblongata contains more than the posterior portion.
The pigment is chiefly found in a curved line, placed in the lower
and outer parts of the grey matter; the amount present varies in
different specimens.

b. The Cerebellum and Valvula cerebelli.

a. External form. The cerebel/um is a thin, semilunar plate,
which projects between the optic lobes and the fourth ventricle,
its base covering the most anterior part of the ventricle; the
posterior surface possesses a very faint median fissure (Reissner).
The valvula cerebelli (Velum medullare anterius, Reissner) is the thin
lamella which connects the anterior surface of the cerebellum with
the optic lobes.

8. Minute structure. By means of longitudinal, vertical sec-
tions, the posterior surface of the cerebellum is seen to be covered
with epithelium ; in the lower part of the surface this is columnar
or conical, above it is flattened: immediately beneath, that is in
front of this is a finely granular layer, with very closely packed and
granular nuclei. In front of these is a stratum of nerve-fibres
forming the second layer of the cerebellum.

Still more anteriorly is the third layer of the cerebellum, an
irregular double layer of large cells (Purkinje’s cells, Denissenko) ;
the cells have an average length and breadth of o-o40 mm. and
o'015 mm. respectively ; they are pear-shaped or of spindle-form,
and possess usually two well-marked processes, one passing into
the layer behind, the other forwards into the anterior layer to be
immediately described, while other less distinct processes radiate
irregularly in all directions. The fourth and most anterior layer
of the cerebellum is a thick stratum of nerve fibres with numerous
nuclei (0'006 to o:008 mm. diameter), The fibres are for the
most part arranged transversely, but some course in various direc-
tions. These fibres underlie the flattened i asin which covers
the anterior surface of the cerebellum,

I

sna ine

THE CEREBELLUM. 149

The fibres of the second layer ©

course, for the most part, in an almost
vertical plane; they connect the cere-
bellum with the optic lobes (processus
cerebelli ad corpora ligemina) and with
other parts of the brain.

The fibres of the fourth layer re-
ceive numerous long processes from
the large cells of Purkinje; they form
a large commissural system, which can
be followed ventrally on each side into
the pars commissuralis. A part of the
fibres ends here in the grey matter, a
second portion enters the auditory area
and forms a descending auditory root,
a third part joins the lateral columns
Gn the medulla oblongata), and more an-
teriorly some join the ventral columns.
The descending fibres from the cere-
bellum, together with the jibrae arcu-
atae found in the ventral columns,
indicate the presence of a pons Fa-
rolii. The fibres of this ventral com-
missure decussate only on its dorsal
surface (K6ppen).

The Valvula cerebelle® contains a few

_medullated fibres and the roots of the

trochlear nerves; these pass from the
medulla oblongata into the valvula
cerebelli, cross in the median line, and
then proceed forwards as the troch-

. lear nerves.

The pigment in the pars commissu-

Ventral view of brain of Rana
esculenta.

Cho i

He Cerebral hemispheres.

Hy Pituitary body,

Lol Olfactory loba,

L.oB Origin, of olfactory nerve from
the cerebral hemisphere.

it Temipa terminalis. = -

Mo Medulla oblongata.

To Optic tract.

Tuc Tuber cinereum.

r a ! root of the olfactory nerve.

II Optic nerve?

IIT Oculo-motor nerve.

IV Trochlear nerve.

VI Abducens nerve. ;

¥, Vi, VI Trigeminal, facial, and
auditory nerves.

IX, X, XI Glossopharyngeal, pneumo-
gastric, and accessory nerves.

ralig is arranged in a curved line similar to that found in the me-
dulla oblongata, but the line is shortened at either extremity, and
consequently does not extend into the cerebellum.

e. The optie lobes and Crura cerebri. (Corpora geminata and

- Pars peduncularis, Reissner; Lotus opticus, Stieda; Vierhiigel,

Tiedemann ; Vierhiigel (Zweihiigel) and Pedunculi cerebri, Schiess ;

Mesencephalon, Baxley.)

150 THE NERVOUS SYSTEM,

a, External form (Figs. g8, 102, 103 Lop). The optie lobes
are two promi-

Hig: t05: nent ovoid bodies

Rey ——!/ Thos) i i MM; sy ately in front of
MS/fPinZy ih UTE the cerebellum,
and connected
with it by the
valvula cerebelli ;

fp Lot Te ioe posteriorly they
[To Tue Hy Mo touch each. other

Lateral view of brain of Rana esculenta, in the median

Ad Choroid plexus, Tu.c Tuber cinereum. plane, while an-

C Cerebellum. I ist : “ :

Gp Pineal body. I’ and § Tt of olfactory nerve. teriorly they di-

He Cerebral hemisphere. iI Optic nerve.

Hy Pituitary body. IV Trochlear nerve. verge and thus

L.ol Olfactory lobe. V Trigeminal nerve. - eonstitute the

L.ol. Disc at origin of second root.VII Facial nerve, 5

L.op Optic lobe. VIII Auditory nerve, widest part of

Mo Medulla oblongata. IX, X, XI Glossopharyngeal, pneumo- aun Beit

Tho Thalamencephalon, ; gastric, and accessory nerves, the brain m the

To Optic tract, anglethus formed

is the thalamencephalon. The optic lobes are always more darkly
pigmented than any other part of the central nervous system.

The Crura cerebri are two columns of white matter, placed beneath
the optic lobes, and partly hidden by the pituitary gland. At their
junction with the medulla oblongata, or rather with the pars com-
missuralis, is a very slight transyerse fissure ; at the same point the
ventral longitudinal fissure is interrupted by an extremely small
grey tubercle (Stieda).

8. Internal structure. From the anterior extremity of ‘the
fourth ventricle a canal, the Sylvian aqneduct (dgueductus Sylvi,
iter a tertio ad quartum ventriculum), may be traced forwards under
the cerebellum, in the median line of this section of the brain. At
about opposite the middle of the length of the optic lobes the canal
is dilated and communicates with the cavities or yentricles (Ventri-
culi lobi optici, Stieda) enclosed by these; a general cavity is
formed, which in transverse section has something of the form
of the letter T. The roof of the cavity is thinner than the floor ;
this is especially the case in the median plane opposite the superipr
longitudinal fissure between the optic lobes; the floor is thinned
in the middle line by the descending portion of the cavity. The
cavity of each optic lobe extends both forwards and backwards
beyond its point of communication with the dilated Sylvian aque-

:
:
:
:

THE OPTIC LOBES. 151

duet, hence in a transverse section taken in front of this point
(Fig. 104 2’) the cavity of either side appears to be isolated; in
a horizontal and longitudinal section (Fig. 105 4g) the general
arrangement of the parts may be well seen.

The grey matter
is chiefly arranged
in a layer so as to
surround the cavity

(Fig. 104), this layer ~

being deeper on
either side of the

descending portion

of the cavity than 4
elsewhere. For the

rest the grey matter
is much interspersed

among the white

matter, except at the
circumference of the
section, which is en-
tirely formed of white

matter. It contains ==

a large number of
small cells, of which
the nuclei are alone
visible; in the parts
mentioned where the
layer is most marked
these cells are ar-
ranged in oblique
rows, between which
pass fine bundles of
medullated _ fibres

Fig. 104.

Transverse section through the anterior portion of the optic lobes
opposite the origin of the motor-oculi nerve ; from Stieda (mag-
nified 30-80).

h
i’

vee Sak

Lower portion of cavity.

Lateral portion of cavity.

Ganglia of oculi-motor nerve.
Oculo-motor nerve.

Large cells of the optic lobe,

Roof of optic lobe.

Posterior commissure.

Anterior diverticulum of the cavity.

(Fig. 104, between wu and h’). A group of large cells (Fig. 104 z) is
found on either side of the middle line and under the floor of the cavity ;

the cells are about 0-032 mm. long, and o’016 mm. broad ; the oculo-

motor nerve may be traced to this group, which is the oculo-motor
nucleus. A small commissure of decussating fibres connects the
nuclei of opposite sides (K6ppen).

The substance of the roof of the optic lobes (Fig. 104 2) is

arranged in very distinct layers: above is a layer free from cells ;

152 THE NERVOUS SYSTEM.

the fibres of this layer are extremely fine and delicate, and have
not been accurately traced ; under this is a nuclear layer ; a second
layer of fine fibres fallowia: which is succeeded by a second layer of
nuclei ina granular matrix, and lastly epithelium (Stieda). (Reissner
describes three nuclear layers in Bufo variabilis, and this is also the
case in R. temporaria, G. H.; according to Képpen, the number is
variable.) In the anterior portion of the roof a distinct bundle of
fibres may be made out; externally they bend downwards, aaa can
be traced as far as the crura cerebri.

Fibres corresponding with the commissural and arched fibres of
the medulla oblongata are continued into the hinder portion of the
crura cerebri, the change from pars commissuralis to crura .cerebri
being: very gradual, The longitudinal white fibres are much in-
creased in number in the crwra cerebri, and a portion of them can
be traced to the nucleus magnus.

A peculiar irregular group of large cells (Fig. 104.) is found
where the roof meets the crura cerebri ; these vary in diameter from
0°024 to 0040 mm., and their processes are very indistinct.

The fibres of the optic tracts arise, according to Képpen, from
two different origins: the one lies on the hindermost part of the
optic lobe ; from this point the fibres curve downwards and forwards
to form longitudinal fibres; this root Képpen names the ventral
ascending root, it can be ante through the entire length of
the organ. The second root arises in the tectum opticum near the
longitudinal fissure; it is smaller than the foregoing, and has
been named the dorsal ascending optic root. The fibres of these
two roots unite anteriorly near the posterior commissure, at which_

point they receive additional fibres (Képpen). Bellonci traces: a

large proportion of the fibres of the optie tract to the nucleus
magnus, which pair of nuclei, as already stated, he regards as the
posterior pair of corpora quadrigemina of higher animals. ;
The pars peduncularis is the continuation of the pars commissu-
- ralis underneath the optic lobes; a gelatinous mass lying in the
median plane and containing numerous isolated nuclei (Ganglion
interpedunculare) divides it into two lateral halves. The longitu-

dinal fibres are ungrouped posteriorly, but arranged in rounded *

strands in the middle, especially dorsally; anteriorly the grouped
arrangement is lost and the number of fibres diminished.

The pigment of this region has, in a transverse section, an outline
which has something the form of a lyre ; commencing on either side
of the median line, and underneath the deepest portion of the eavity,

eS ee a

—

‘marked depression (Fig 98 @), the origin of

between the cerebral hemispheres (Figs. 98,

_ a fine thread of connective-tissue.

. THE THALAMENCEPHALON. 153

- 6

the pigment line passes, first, directly outwards ; then suddenly turns
upwards and slightly outwards parallel with the wall of the deeper
part of the cavity; it then curves outwards to pass below the cavity of
the optic lobe, where it divides, one portion passing outwards, the other
between the Sylvian aqueduct and the ventricle of the optic lobe.

d. The Thalamencephalon (Huxley), (Lojus ventriculi tertii,
Stieda ; Thalami optici, Reissner ; Thalamus opticus s. Lobus ventri-
euli tertii, Stannius ; Ganglien der Haemisphaeren, Carus).

- a. External form. From above (Fig. 98 Zio) the thalamence-

phalon is seen as a lozenge-shaped mass lying in front of the optic
lobes, and behind and between the diverging posterior ends of the
cerebral hemispheres ; it is covered by a thick vascular membrane, the
choroid plexus, through which passes the pedicle of the pineal
body (G/andula pinealis). On removing the choroid plexus:a small
aperture is seen in the roof of the thalamencephalon, connecting
the hollow pedicle of the pimeal gland with the third ventricle.
The ventricle appears as a narrow slit in the median line, its
walls being formed by the optic thalami. By Fig. 105.

pressing aside the cerebral hemispheres the pos-
terior commissure (Commissura posterior) may
be seen lying quite in front and deep in the
cleft-of the ventricle. Immediately behind the
pedicle of the pineal body is a slight but well-

which has not been investigated (Wiedersheim).
_ The choroid plexus’is continued forwards

103 Ad) for some distance, and terminates in

The under surface of the thalamgencephalon
(Fig. 102) is divided into two parts by the
optic chiasma (C/o): the anterior portion
(Lt) is the Jamina terminalis (Substantia cinerea
anterior); the posterior (Tu.c) the tuber cine-
reum. "The lamina terminalis is bounded on —__ a2
either side by the cerebral hemispheres. The “the tin techow the we

tuber cinereum (Figs. 102, 103 Tu.c) isa small le.

. P . ‘ ‘ = q Ventricles of optic lobes
median swelling immediately behind the optic and the aqueduct of
chiasma, and caused by the depression of the py Thind ventric,
floor of the third ventricle to form the infun- 2%? Feramen of Monroe.

. ‘ . 4 RS : . 3 Se Lateral ventricle.
dilulum (Diverticulum infundibuli, Reissner). ‘Ye = Fourth ventricle.

154 THE NERVOUS SYSTEM.

The pituitary body (Hypophysis cerebri) is a flattened sac, placed
behind the ¢uder cinereum and continuous with it by means of the
mfundibulum,

8. Internal structure. The aqueduct of Sylvius, after commu-
nicating with the ventricles of the optic lobes, again contracts
(Fig. 105), but still remains somewhat larger than before. In the
thalamencephalon the Sylvian aqueduct opens into the third
ventricle, which gradually assumes the form of a vertical slit with
the walls bulging slightly outwards in their upper parts. The
thin roof of this ventricle, where complete, contains a band of
transverse fibres. ‘The floor is depressed both before and behind
the part immediately above the optic chiasma, the posterior de-
pression lying above the tuber cinereum, which here descends
towards the infundibulum: a transverse section through this por-
tion of the third ventricle has the form of a square standing on
one angie, the superior angle being produced into the vertical
slit of the general cavity. The anterior depression is formed
by the general cavity being prolonged downwards and forwards to
the damina terminatis in the form of a narrow and shallow slit.

The white and grey matter of the thalamencephalon are only so
far distinct in that the portion immediately surrounding the cavity
is darker than the rest of the section. In the immediate neighbour-
hood of the cavity are many small cells and nuclei, which become
scarcer further from the ventricle; they are arranged in rows,
separated by a fibrillated matrix. On either side is a distinct bundle
of longitudinal fibres, the ‘round bundle’ of Képpen, which come
from the optic lobes but appear to arise from either the pars com-
missuralis or the medulla oblongata, and to receive additional fibres
from the optic thalami; they pass forwards to the base of the
cerebral hemispheres (Stieda). A second set of longitudinal fibres
arises in the substance of the tuber cinereum and passes forwards
to the hemispheres (strand of the Zuber-cinereum and Thalamus,
Képpen); this band, together with the ‘round bundle,’ form a crus
cerebri (Képpen).

The commissural fibres of the thalamencephalon are : (1) a com-
missura transversa Halleri in the posterior portion of the organ ;
(2) an optic commissure, consisting of fibres arising from the thala-
mencephalon (thalamencephalic root) and crossing the median line
to join the optic tract of the opposite side; (3) a probable com-
missure between the optic nerves just in front of the chiasma
oplicorum ; the existence of the latter is not yet proved beyond

THE PITUITARY BODY. 155

doubt ; (4) the large commissure of transverse fibres found in the
roof of the third ventricle ; whether the fibres decussate or not is
uncertain (K6ppen).

The fibres of the large commissure of the roof are, in part con-
tinued into the strand of the 7user-cinereum above mentioned, and
thus conducted to.the posterior parts of the hemispheres (K6ppen).
A group of fibres (Meynert’s band, Képpen) is found in each lateral
wall of the third ventricle; they pass from the region of the nucleus
parcus downwards in a curved course almost parallel with the ex-
ternal border of the thalamencephalon. .

A distinet group of cells may be noted in this section of the brain,
an areiform or circular group (Nucleus parvus, Reissner ; ganglion
of the abenula, Kippen) of large spindle cells (average diameter
0016 mm.), placed under the upper border close to the third ven-
tricle; the group extends alongside the whole length of the
ventricle. A second group lymg in the middle and posterior parts
beneath the ventricle, Képpen names the ‘ ventral nucleus’ of the
thalamencephalon.

The pigment in the posterior part of the thalamencephalon is
arranged in a manner similar to that in the optic lobes and erura
cerebri ; anteriorly where the third ventricle is prolonged forwards
and downwards the arrangement is different ; the pigment lies in
a curved line above the process of the ventricle, with its concavity
directed downwards, each end bifurcating, in order that one branch
may pass upwards, the other downwards.

_ The pineal body! is a small vesicle placed underneath the skin
above the fronto-parietal bones ; in the embryo it is connected with
the third ventricle by means of the pedicle? already mentioned ; the
skin covering the body is always paler than the surrounding skin, and
the usual cutaneous glands are absent in this part ; the paler spot on
the head may always be found, but is more distinct in Rana tempo-
raria than in Rana esculenta. The structure on the roof of the third
ventricle, which is usually known as the pineal body, is nothing more
than a thicketied portion of the choroid plexus, and consists of a
group of convoluted vessels surrounded by pia mater, which is de-
scribed by Wyman as being covered with ciliated epithelium (R.
pipiens). The true pineal body is a small body with an outer con-

* Compare Ehlers, Ueber die Zirbel der Haifische, Zeit. f. wiss. Zool. 1878, Vo .
XXX ; and Balfour, Development of the Elasmobranch Fishes, chap. ix.

* Wiedersheim states that the pedicle is hollow, and regards the part formerly
known as the pineal body as a thickened portion of this pedicle.

156 THE NERVOUS SYSTEM,

nective-tissue capsule, derived from the pia mater ; this encloses an
irregular mass of epithelial cells; according to de Graaf a twig of
the ramus supramaxillaris reaches it subcutaneously, and a blood-
vessel accompanies the pedicle through the foramen parietale, Ac-
cording to Darkschewitsch, the pedicle contains medullated nerve-
fibres derived directly from the brain.

The pituitary body (Figs. 102, 103 Hy) when examined with
a lens is seen to consist of two portions: an anterior, superior, and
smaller white portion, and a larger, inferior, posterior, and reddish
portion. The anterior portion has the form of a very small, flat
disk, and is enclosed in a connective-tissue capsule which sends
in larger and smaller processes. In either transverse or longitu-
dinal section it is seen to be formed of two horizontal layers
separated by a line of blood-vessels and connective-tissue. The
upper layer consists of a granular and reticular matrix, containing
many nuclei (averaging 0°006 to o’o10 mm. diameter), and divided
into irregular rounded or polyhedral spaces by bands of tissue
derived from the capsule. This layer is more vascular than the
lower. The lower layer consists of a mass of clear, nucleated
rounded or polyhedral cells (0°016 to 0024 mm. in diameter ;
nuclei from o:008 to o:012 mm. in diameter, Reissner), pierced
by very fine connective-tissue septa derived from the capsule.
The septa are, for the most part, vertical and longitudinal
(Reissner), the blood-vessels are very few.

The posterior larger portion of the pituitary body (Fig. 106) is
also compressed from above downwards, and in transverse section
as an oval outline. It possesses an external thin connective-
tissue capsule, which sends in fine processes to support a mass
of convoluted tubes, between which course a few blood-vessels ;
these tubes possess an outer nucleated basement-membrane, and
are lined with a single layer of more or less cylindrical epithelium,
which entirely fills the tube ; hence the tubes possess no lumen.
The tubes are from o'04 to o’o8 mm. in diameter; the cells are
clear or granular, and possess distinct, rounded nuclei.

e. The Cerebral Hemispheres and Olfactory Lobes. The
cerebral hemispheres (Lodi hemisphaerici, Stieda; Loli cerebrales,
Reissner ; Centralmasse des Geruchssinns, Carus ; Hemisphaeren
des grossen Hirns, Tiedemann; Grosse Hemisphaeren, Schiess ;
Prosencephalon, Huxley). The olfactory lobes (Lubercula offac-
toria, Stieda ; Lobi olfactorii, Reissner ; Riechkolben, Schiess ; Rhi-
nencephalon, Huxley).

THE CEREBRAL HEMISPHERES. 157

a. External form (Figs. 98, 102, 103 He and L.o/). The two
cerebral hemispheres form together the largest section of the
‘brain ; from above they are seen to be separated by a dorsal lon-
gitudinal fissure, which is here well marked : each hemisphere is an
ovoid body with the smaller end directed forwards and continuous
with the corresponding olfactory lobe; the Fig. 106.
posterior end forms one half of the anterior
boundary of the thalamencephalon. The
olfactory lobes are two elongated, rounded
bodies directly continuous with the cor-
responding cerebral hemispheres, and like-
wise partially separated in the median line ING
by a dorsal longitudinal fissure: at the section through the lower division
point of union of the cerebral hemispheres pl aS ii
and olfactory lobes is a faintly marked a Tubes lined with epithelium.

_ transverse depression. ~ * oe

On the ventral surface the parts are again marked off from
one another by a corresponding ventral longitudinal fissure and a
transverse groove; the two longitudinal fissures being continuous,
anteriorly, between the olfactory lobes. The cerebral hemispheres
appear to be more widely separated behind (Fig. 102) than is
the case on the dorsal surface, and im the space so formed is
the Zamina terminalis (Lt). Seen from the side, the slight depres-
sion of the upper surface, between the cerebral hemispheres and
the olfactory lobes, is seen to be continued downwards and»
slightly backwards to join the corresponding groove on the inferior
surface. :

The longitudinal fissures are shallow and do not meet, except
at one point, at about the middle of the cerebral hemispheres
(Fig. 105). The olfactory bulbs arise superficially (Figs. 102, 103 I’
and L.o/) from the whole length of the olfactory lobe, between the
anterior extremity (J’) and the posterior (Z.o/), where they are also
attached to the cerebral hemispheres.

8. Internal structure. The cerebral hemispheres and olfactory
lobes are hollow, the common cavity of each side being known
as the lateral ventricle (Ventriculus Jateralis); these ventricles
communicate with each other, and with the third ventricle
(Fig. 105). The narrow aperture by which the lateral ventricles
communicate is known as the Foramen of Monro (MF); it
communicates with the third ventricle posteriorly, and with the
_ space between the cerebral hemispheres anteriorly, and thus forms

158 THE NERVOUS SYSTEM.

a common cavity (Ventriculus communis loborum hemisphaericorum,
Stieda).

In general terms, each ventricle may be said to be a semilunar
eavity, prolonged backwards and forwards (Fig. 107 c); the outer
wall is always more or less concave, while the
inner varies according to the part of the hemi- —
sphere examined. At the anterior and posterior
extremities the inner wall is convex and bulges
into the cavity (Fig. 107); in the middle portion
of the cavity the inner wall presents a longi-
tudinal groove (Ventriculi lateralis cornu inter-
Tecsiaedaras section um, Reissner), (Fig. 108 d), and consequently

pag oh ehe st the inner wall has here two rounded masses, an

bral - hemispheres; upper and a lower (Corpus striatum, Wiedersheim),

from Stieda. . . : : .

Lateral ventrice, Projecting into it. By tracing them backwards
< Colgan: | eae and forwards, the lower swelling is seen to in-
d Longitudinal fibres. @rease at the expense of the upper, while at the
thn tt de tia Same time the lateral grooves disappear; the
ventricle. outline of the cavity shown in Fig. 107 is then
obtained. The roof of the ventricle is arched and broader than
the floor, which, in the middle part, exists only as a vertical slit
(Fig. 108), (Ventriculi lateralis cornu inferius, Reissner): towards
the anterior and posterior extremities it widens and becomes
shallower (Fig. 107).
Fig. 108. The cerebral hemispheres and olfactory lobes
. are composed of a fine granular matrix, enclosing
spindle-shaped, rounded, or pear-shaped nerve
cells and nuclei, and containing: very fine fibres.
The cells (Fig. 109 4) are more numerous towards
the ventricle, and somewhat sparse towards the
Transverse section near SUPCTficial surface. The cells are of two chief
the middle of the cere- sizes, the smaller and more numerous average

bral hemispheres, ; . .

CERES 07004 mm. to o‘oo8 mm. in diameter ; they are
set “heed acl found chiefly in the deeper portions of the

section, but also form a very thin irregular
layer beneath the pia mater: the larger cells have an average
diameter of o‘o1o mm. to o'o12 mm., and are placed towards
the periphery, especially in the dorsal part of the inner wall.

In this irregular collection of cells the following centres have
been described : (1) The nucleus, through which the corpus callosum
passes (Képpen); (2) the lower internal or median cell-area

THE CEREBRAL HEMISPHERES. 159

(Osborne), situated above the foregomg nucleus in the posterior and
middle portions of the hemispheres ; (3) the upper internal cell-area
(Osborne) is the area of large cells ir the dorsal part of the inner
wall; (4) the Corpus striatum (Osborne) is a mass of cells between
the corpus callosum and the commissura anterior; Koppen doubts
the correctness of Osborne’s opinion, and suggests that a group of
cells found in the wall of the third ventricle in front of ‘ Meynert’s
band’ may perhaps be a corpus striatum.

Fig. 109.

From a transverse section through one of the cerebral hemispheres ; from Stieda.
(Magnified 360 times.)
a Epithelium of lateral ventricle.
b Nerve cells,
e Connective-tissue processes from the Pia mater.

A bundle of longitudinal medullated nerve-fibres, the ‘ round

] _ bundle,’ is found on either side of the median line (Fig. 107 d),

and near the lower border in the posterior portion of this region ;
these fibres can be traced from the posterior section of the thala-
mencephalon ; they diminish in number as they course through the
base of the cerebral hemispheres, and are ultimately lost in the
lower anterior part of the outer walls. A second strand of lon-
gitudinal fibres is the continuation of that of the Tuser-cinereum
above described, which can be followed to the outer wall of the
posterior part of the ventricles, and to the anterior commissure.

The commissures are: (1) The corpus ca/losum, a large bundle of
transverse fibres, seen best in a transverse section, at the point of
junction between the /amina terminalis and the cerebral hemi-
spheres, forming an arch over the roof of the anterior prolongation
of the third ventricle. The fibres course to the inner and anterior
parts of the hemispheres, and are situated chiefly behind the jo-
ramen Monroi. To this commissure must be added those fibres
which unite the two olfactory lobes, and possibly the fibres (Com-
missura posterior) found in the roof of the third ventricle (Képpen).
(2) The Commissura anterior (Stieda), a smaller set, found immedi-

160 THE NERVOUS SYSTEM.

ately under the floor of the common ventricle, forming in their
course outwards a curve, with the concavity directed downwards.
This commissure connects the ‘round bundles’ of opposite sides,
and those fibres coursing with the ‘round bundles’ to the olfactory
lobes constitute the pars olfactoria of the commissura anterior. To
this commissure must also be added some fibres found on the ventral
surface of the commissura anterior and connecting the two strands
of the Zuber-cinereum; an unusually coarse strand of these fibres
can be traced to the inner wall of the ventricle, and is termed the
pars olfactoria interna by Osborne.

The general structure of the olfactory lobes resembles that of
the hemispheres; the olfactory nerves arise each by two roots, an
outer and inner. The outer root arises from the outer wall near the
groove between the corresponding hemisphere and olfactory lobe ;
the inner or anterior root arises from the anterior surface of the
olfactory lobe. Both roots have a peculiar method of origin from
the extremely fine fibrillar network of the matrix (Nerve-fibre-
conglomerate, Képpen), in which are rounded dark bodies known
as ‘ glomeruli ;” in the ‘ glomeruli’ dark points and nuclei are seen,
between larger and smaller bands of nerve-fibres. K6éppen holds
that all the sensory nerves of the brain arise in a similar manner.

A decussation takes place between the two inner roots of the
olfactory nerves; possibly the external roots are connected by
means of the commissura anterior.

Very little pigment exists in the cerebral Re ee or olfac-
tory lobes, the greater portion is found in the upper part of the
inner walls of the cerebral hemispheres.

The epithelium of the ventricles of the brain, like that of the
central canal of the spinal cord, consists of conical cells with
their bases directed towards the cavity, and their apices directed
peripherally and prolonged into distinct processes (Figs. 104, 109 a).
In such situations, as the choroid plexuses, where nervous tissue is
absent and the cavity is completed by pia mater alone, the epithelial
cells are flattened. Everywhere else it is ciliated! and possesses dis-
.tinct round nuclei which are as broad as the cells themselves. The
epithelium is somewhat irregularly and sparsely pigmented ; the
ventral parts of the central canal of the spinal cord, of the fourth
ventricle, and of the Sylvian aqueduct are always more pigmented
than the dorsal parts.

1 Schmidt (I. c.) states that the epithelium of the central canal of the spinal cord is
not ciliated.

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161

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THE CEREBRAL HEMISPHERES.

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162 THE NERVOUS SYSTEM.

C. THe Coverines oF THE BRAIN AND Spinat Corp.

1. The Pia mater closely invests the whole of the brain and
spinal cord ; it may, in fact, be regarded as the flattened, outermost
layer of the connective-tissue material which supports the nervous
elements ; fine processes (Fig. 109 ¢) pass radially from its inner
surface to join the general connective-tissue matrix or neuroglia.
It is usually pigmented, those portions covering the optic lobes
and spinal cord being especially deeply pigmented: on the cerebral
hemispheres it contains very little pigment; at times, indeed,
in &. temporaria, pigment is absent from this part.

The pa mater is continued on to the choroid plexuses and pituitary
body, and on to the pineal body by means of the pedicle; the
membrane is very vascular, and forms, especially for the cerebral
hemispheres and the olfactory lobes, a very important source for
the direct supply of blood-vessels.

2. The Dura mater, or lining membrane of the cranial cavity and
vertebral canal, is a connective-tissue membrane containing many
very much branched, pigmented cells. This membrane is not so
deeply pigmented as the pia mater, except in that portion covering
the cerebral hemispheres and the olfactory lobes, which is much
darker than the corresponding portion of the pia mater.

3. The arachnoid membrane is the layer of endothelial cells
covering the inner surface of the dura mater: by means of the
blood-vessels and nerves, etc., it is continued on to the pia mater
of the spinal cord and brain, which it in like manner closely invests.
Masses of calcareous crystals are found between the epineurium
and the arachnoid (Wiedersheim) on each spinal nerve at its exit
from the intervertebral foramen, also on the trigeminal nerves in
the cranium. Additional smaller and more irregular masses are
found on the dorsal part of the dura mater of the spinal cord.

D. Tue VessEts oF THE BRAIN anp Spinat Corp. (Fig. 110.)

The arteries of these organs are derived from the internal carotids
and the arteriae vertebrales, As soon as the internal carotid arteries
reach the cranial cavity each divides into two branches, an ante-
rior (Ramus anterior, Schébl') and a posterior (Ramus posterior,
Schébl) ; the anterior branches course forwards on the lower part of

1 These names are those adopted by Schébl for corresponding vessels in the newt, -

the translator has accepted them as being suitable, with slight modification, to the
vessels of the frog.

Ses i NN i a la a

: VESSELS OF THE BRAIN AND CORD. 163

the surface of the brain as far as the anterior portion of the tha-
lamencephalon, where they again divide; one division, arteria
lobi hemisphaerici inferior externa (Schobl), continues forwards along
the outer surface of the cerebral hemisphere and of the olfactory
lobe as far as the olfactory bulb, where it may still be distinctly
seen; it gives off branches to the adjacent parts in its course for-
wards. The vessels of the two sides communicate with each other
by means of delicate transverse vessels (Arteriae communicantes ante-
riores). The second division, arteria lobi hemisphaerici superior in-
terna (Schobl), of the ramus anterior courses on the thalamencephalon
to the dorsal surface, gives a large branch to the choroid plexus of
the fourth ventricle, and runs forwards in the dorsal longitudinal
fissure ; it supplies vessels to all the neighbouring parts.

_ The rami posteriores converge as they course backwards, and ulti-
mately unite to form an arteria basilaris, which is continued in the
_ median line of the under surface of the spinal cord as the arteria
_ spinalis anterior. The ramus posterior gives off, in its course, many
small vessels to the neighbouring parts, and two larger vessels on
_ either side, one of which, the arteria (obi optici (Schobl), is distributed
to the optic lobes, while the other passes to the pituitary body.

The branches of these vessels form a network in the pia mater,
from which the nervous tissue is supplied ; they also send numerous
branches directly into the brain and cord, and these have a similar ar-
‘Tangement for all parts of the brain with the exception of the cerebral
hemispheres and olfactory lobes ; more or less vertical branches arise
from the posterior parts of the upper borders of the rami anteriores,
from the whole of the rami posteriores, and from the arteria basi-
aris; these course upwards from their place of origin into the corre-
_ sponding part of the brain, give off a few branches in the white
_ matter, and then branch freely, and at somewhat sharp angles,
in the grey matter. In the pars commissuralis a large branch may
ir be traced from the ramus posterior on either side upwards into the
_ cerebellum: almost to its upper border. The vessels of the cerebral
Miisnispheres and olfactory lobes seem to possess no other definite
| arrangement than that described above. The grey matter seems,
|} on the whole, to be more vascular than the white; the vessels of
| the latter are chiefly arranged radially to the surface, and run in
courses which are more or less straight; the vessels of the grey
matter are more irregular and sinuous.

_ The Arteria spinalis anterior courses along the whole length of
the spinal cord, giving off lateral branches and communicating with
M2

164 THE NERVOUS SYSTEM.

rami spinales (branches of the Arteria vertebralis). These branches
form a plexus in the pia mater, from which vessels pass at irregular
points into the cord ; one set of small vessels, described by Reissner,
pass in a straight course from the superior longitudinal sinus
towards the substantia reticularis, where they divide. Other branches
pass directly from the arteria spinalis anterior, through the ventral
longitudinal fissure, and there divide; the twigs as a rule avoiding
the septum medium and passing in greater part towards the ventral
Fig. 110. horns. The vessels in the white matter are
for the most part radial and straight, while
in the more vascular grey matter they are

irregular and more sinuous in their course.
The choroid plexus of the third ventricle
(Plexus choroideus ventriculi tertii, Reissner)
_ lies, as already described, on the roof of the
third ventricle ; it is somewhat triangular in
form (Plexus venosus triangularis, Schébl), and
is evidently a prolongation of the pia mater,
with an increased supply of vessels. It re-
ceives, at its anterior angle, veins from the
cerebral hemispheres and the adjacent parts.
The under surface is covered with a layer of
ciliated pavement epithelium. At the pos-
terior angles of the plexus the veins commu-
nicate on either side (Fig. 110) with the
anterior lateral prolongation of the vena

Diagram to show the Vena . - ‘ . ni -
spinalis posterior, the Ve- spinalis superior, and with the internal jugular

nite ame: ee
the origin of the Vena Veln. ‘The small body usually named the

pagetarie titern, pineal body, and placed on the roof of the
Po spiotal jusclex. ventricle, is only a small thickened portion of

op Optic lobes. j a s
AY ee the plexus, and consists of a group of convo

spp Vena spinalis posterior. luted blood-vessels. This plexus sends a con-
siderable bunch of vessels into the upper part of the third ven-
tricle. The choroid plexus of the fourth ventricle (Plexus choroideus
ventriculi quarti, Reissner) is a triangular membrane, slightly at-
tached to the borders of the fourth ventricle. Its upper surface
is flat and bounded at either side by a large vein, the vena
spinalis superior ; anteriorly it 1s bounded by the cerebed/um. The
under surface is not flat; in the middle line is a slight furrow
corresponding to the position of a median vessel, which may, when
injected, be seen from the dorsal surface; from it a number of

1, eR i. opal
“- " " vant

VESSELS OF THE BRAIN AND CORD. 165

short vessels pass outwards and slightly backwards to the outer
border. The connective-tissue between these vessels is pushed down
into the cavity ; in thismanner one obtains a double row of flattened
villous-looking bodies, which frequently have their tips pigmented.
The under surface of the plexus is clothed with flattened, ciliated
epithelium.

On either side of the pituitary body is another small venous
plexus (Plerus lateralis, Schébl); it communicates above with the
posterior angle of the choroid plexus of the third ventricle; exter-
nally, with the internal jugular vein ; and internally with its fellow
of the opposite side by more or less irregular transverse vessels,
which, together with a median vein from the fissure between
the cerebral hemispheres, form an irregular cireulus venosus around
_ the pituitary body. These plexuses receive blood from the lower
_ part of the cerebral hemispheres, the thalamencephalon, the optic
_ lobes, and from the pituitary body. The veins of the spinal cord

open into the dorsal, rena spinalis posterior (Fig. 110 spp), which
bifureates at the posterior angle of the fourth ventricle, one division
passing to either side and forming, as already described, the outer
border of the choroid plexus ; anteriorly it opens into the internal
jugular vein (Fig. 110 72).

; The blood-vessels, both arteries and veins, are irregularly pig-
_ mented, both on the surface and in the interior of the central
_ nervous system; those of the cerebral hemispheres and olfactory

___ lobes have very little or no pigment.

166

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Ms.ob
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F
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phi

DESCRIPTION OF THE FIGURES ON PLATE I.

&
7
;

G

Fig. 111. Dorsal view of the orbit, etc.; deep dissection. e
Course of the palatine nerve, II Optic nerve. 5
Fibrous plate. IIT Motor oculi nerve.
M. depressor maxillae. IV Trochlear nerve.
Terminal branches of the ophthalmic nerve. Vb R. palatinus ’
Facial with R. anterior of the glossopharyngeal. Ve R&.maxillo-mandibularis ( of the trigeminal
Terminal twigs of the ophthalmic nerve. Ve’ RB. maxillaris nerve.
Muscular twigs of the Ram. maxillaris, Vd R. mandibularis

M. intertransversar. capitis superior.

Twigs of upper eyelid. ;

Terminal twigs of the Ram. maxillaris.

M. levator anguli scapulae.

M. pterygoideus,

M. sterno-cleido-mastoideus.

Sympathetic nerve.

M. temporalis.

Nasal branch.

Union of facial nerve with Ram. anterior of
the glossopharyngeal nerve,

Olfactory nerve.

Fig. 112. Dorsal view of the orbit, etc. ; superficial dissection.

External branch of the ophthalmic nerve.
Internal branch of the ophthalmic nerve.
Terminal twigs of the ophthalmic nerve.
Optic nerve.

Motor oculi nerve.

Trochlear nerve.

Fig. 113. View of roof of mouth ; mucous membrane, ete., removed.

Heench of the Ram. palatinus to the Harderian

Branch of the Ram. palatinus to the inter-
maxillary gland,

Inosculating-branch of the Ram. palatinus,

Internal naris.

Cutaneous branch of the Ram. palatinus.

Fibrous plate.

Ramus mandibularis of the facial nerve.

Intermaxillary gland.

Harderian gland.

Eyeball.

M. masseter.

i, M. obliquus inferior.

Epier. jaw,
. retractor bulbi.

Cardiac nerve.

Union of facial and Ram. anterior of the
glossopharyngeal nerve.

Ram. hyoideus of the glossopharyngeal nerve.

M. levator angi scapulae,

M. longissimus dorsi.

M. masseter.

Ram. mandibularis of the glossopharyngeal
nerve.

Hypoglossal nerve.

Brachial nerve.

Anterior cornu of the hyoid bone.

M, obliquus internus,

M. petrohyoideus I.

M. petrohyoideus IT,

M. petrohyoideus III.

M. petrohyoideus IV,

Fig. 115. Dissection of the floor of the mouth.

M. depressor maxillae.

, United facial nerve and Ram, anterior of the

glossopharyngeal nerve.
M., geniohyoideus.

Ram. hyoideus of the glossopharyngeal nerve.

Heart.

Lung.

Ram, mandibularis of the glossopharyngeal
nerve.

Hypoglossal nerve,

Brachial nerve.

Anterior cornu of the hyoid bone.

Momohyoideus.

M. petrohyoideus I,

be underneath them.—Trans.

1 The branches of the vagus which are represented in this figure as crossing the petrohyoid muscles out

Fig. 1141. Lateral dissection of head, ete., to show the cranial nerves, ete.
P

Ve(VL1) Facial nerve.

Vg _ Gasserian ganglion.

VN Trigeminus,

VS Sympathetic nerve.

VI Abducens nerve.

Vil’ Facial nerve.

VIII Auditory nerve.

Xx Ram. anterior of the glossopharyngeal,
X2 Glossopharyngeal nerve.
X3 Pneumogastric nerve.
XG Ganglion nervi vagi.

XI Accessory nerve.

Va Ophthalmic nerve.

Ve R. maxillo-mandibularis,

Ve’ R. maxillaris of the trigeminal nerve.
Vd _ R. mandibularis of the trigeminal nerve.
VI Abducens nerve.

VI’ Ciliary nerves.

ri M. rectus internus,

ri’ M. rectus inferior.

sc M. sterno-cleido-mastoideus.

uk Mandible.

+ Terminal branch of Ram. palatinus.

* Union of facial nerve with Ram. anterior of ©
the glossopharyngeal.

IIT Motor oculi nerve. :

Vb Ramus palatinus of trigeminal nerve. a

Ve . Ramus maxillo-mandibularis of the trigeminal _
nerve.

Ve’ Ramus maxillaris of the trigeminal nerve.

Vd &. mandibularis,

Ve (VII) Facial nerve.

xX Pneumogastric nerve.
X1 Glossopharyngeal nerve.

pp branches of the pneumogastric ti
nerve.

tt’ M. temporalis.

Muscular twigs of the Ram, mandibularis
the trigeminal nerve.

Z Tongue.

Va _ Terminal twigs of the ophthalmic nerve.
Ve Ram, maxillaris of the trigeminal nerve.
Vd Ram. mandibularis of the trigeminal nerve,

Ve (VII) Facial nerve.

Xz Ram. anterior of the glossopharyngeal nerve.
X2 Glossopharyngeal nerve, ;
X3 #Pneumogastric nerve.

X39 Ram. gastrici of the pneumogastric nerve,

X3/ ~=Ram. Jaryngeus.

X3p - Ram. pulmonales of the pneumogastric nerve,
XI Accessory nerve of the pneumogastric nerve, —

ph2 M. petrohyoideus IT.
ph3 M., petrohyoideus IIT.
pha M. petrohyoideus IV.

sc M. sterno-cleido-mastoideus,

sh M. sterno-hyoideus.

sm M, mylohyoideus (submaxillaris),

smt M. submentali

TT Thyroid.

uk Mandible.

us Muscular twigs of the Ram. mandibularis.

‘2 Glossopharyngeal nerve.

X3 + #Pneumogastric nerve.

X3¢ Rami cardiaci of pneumogastric nerve. ‘
X3/ ~=Ram., laryngeus of the pneumogastric nerve.
X3p Ram. pulmonalis of the pneumogastric nerve.

THE CRANIAL NERVES. 167

Il. THE PERIPHERAL NERVOUS SYSTEM.

E. Tue Crantat NERVEs.

(To facilitate reference the original arrangement of this part
has been altered.)

[There are ten pairs of cranial nerves in the frog, which are
numbered in order from before backwards. The mode of origin of
these nerves,and their deeper relations with the respective parts of
the brain to which they belong, have already been described. |

1. The olfactory nerve (J. o/factorius), |(Figs. 97, 98, 102, 103,
111 J) runs a very short course only a few lines in length, and
escapes from the cranium by an opening in the cartilage of the
sphenethmoid into the nasal cavity, where it divides into two branches,
each of which breaks up into a brush of filaments, to be distributed
in the olfactory mucous membrane. The nerve contains no white
fibres]. (See organ of smell, p. 385.)

2. The optie nerve (J. opticus), (Figs. 97, 102, 103, 111 JZ)
_ [arises, as already described, by the optic traet, and joins with its

_ fellow at the optic chiasma or commissure, where part of the fibres
_ pass over to the opposite side (according to Michel all the fibres
_ eross). Each optic nerve then courses outwards, piercing the car-
_ tilage of the cranium and so reaching the eyeball]. (See organ
of sight, p. 408.)
8. The motor oculi (NV. oculomotorius, Oculo-motor, Motor com-
_ munis), (Figs. 102, 111, 112, 113 ZZZ). From its origin it courses
_ outwards and forwards, perforating with a slight obliquity the carti-
_ laginous wall of the cranium, just in front of the Gasserian gan-

_ glion (Fig. 116 J/Z); on reaching the orbit it divides into two

_ branches, between the Levator bulbi and the Rectus internus and in-

| ferior. One branch, Ramus superior, rans over and parallel to the
. Ramus ophthalmicus Trig. and enters the under surface of the

Reectus superior ; the second, lower branch, Ramus inferior, supplies
filaments to the Rectus internus and inferior and to the Obliguus in-
_ ferior. Apparently it exchanges fibres with the ophthalmic division
of the trigeminal nerve.

[That portion of the motor-oculi aati its branch to the
Reetus superior and to that to the Rectus internus contains a
number of nerve cells; according to Schwalbe (7.c., p. 235 and

Pt. XII, Fig. 4) these cells are arranged in four groups or ganglia ;

168 THE NERVOUS SYSTEM.

the second group forms a very slight prominence, and is covered by
a very fine layer of nerve fibres, it also gives off some extremely fine
nerves to the eyeball; this is perhaps a ciliary ganglion (Ganglion
ciliare, Schwalbe). Beard, however, names it ‘ mesocephalie gan-
glion.? The other three groups are simply clusters of ols between
the fibres of the nerve. |

4. The pathetic or trochlear nerve (N. troch/earis, patheticus),
(Figs. 102, 103, and 112 JV). From its origin it courses forwards
with and then crosses the motor-oculi ; it perforates very obliquely
the cartilaginous lateral wall of the cranium, in front of the
motor oculi but above and very slightly behind the optic foramen
(Fig. 116); it runs parallel to and in company with the Ramus
opthalmicus trigemini, and appears to exchange a few fibres with it,
which, however, according to de Watteville, Stannius, Cuvier, and
Wyman, is not really the case. In this course it lies first to the inner,
then to the outer side of the ophthalmic, over which it passes to
supply the Rectus superior. [The pathetic and ophthalmic nerves
are sometimes enclosed in a common sheath (de Watteville).]

5. The trigeminal nerve (J. ¢rigeminus), (Figs. 97, 102, 103,
III, 112, 113, and 114 V) is the largest of the cranial nerves in
the frog ; from its origin it runs outwards and forwards to the skull
wall, and just before reaching this enters the large Gasserian
ganglion. It then passes through the cranial wall immediately in
front of the auditory capsule, and divides at once into two main
branches (Fig. 111 Vg, ete.), the Ramus ophthalmicus and the Ramus
maxillo-mandibularis.

The Gasserian ganglion is a large, yellow, oval ganglion placed
in a depression in the outer wall of the cranium ; it is covered by a
‘periganglionic gland,’ which is similar in structure to that of
a spinal ‘periganglionic’ gland (see p. 180), the fibrous capsule
bemg stronger. This ganglion receives three other nerves besides
the trigeminal, vz. the sixth and seventh nerves, and branches of
the sympathetic.

According to de Watteville, these nerves are arranged on the
lower surface of the ganglion, so that the sympathetic is below,
the sixth above it; then the seventh, while the fifth is uppermost ;
the sympathetic splits into several bundles which join the various
branches of the ganglion; the sixth divides into two bundles, one of
which usually joins the ophthalmic, while the other makes its exit
independently; the seventh splits into two bundles, one of which

Oy ee Ne

53 Fabs :

" ‘THE CRANIAL NERVES. 169

leaves the ganglion as the hyomandibular branch, the other gives
some fibres to the palatine branch of the trigeminal nerve, and is
then continued as the palatine branch of the facial. ]

a. The Ramus ophthalmicus (Ramus nasalis, Fischer ; Ophthalmic
or Orbital Branch, Wyman ; Orbito-nasal or Ophthalmic Nerve,
de Watteville), (Figs. 111 and 112 Va). After leaving the Gasse-
rian ganglion the nerve is directed forwards parallel to the side of
the cranium, between this and the eyeball. It lies beneath the
Rectus superior, but above all the other muscles of the eyeball and
the optic nerve. At the anterior end of the orbit it divides into
two branches (e and f) which pass through apertures (Foramen pro
ramo nasali) in the cartilage of the sphenethmoid, to reach the nasal
cavity, where they lie between the cartilage and mucous membrane.
In this position the nerves supply branches to the mucous membrane
and then pierce the skull to appear on the surface (Figs. 111,
112 9,9,9, 114 Va), the skin of which they supply. The branches
inosculate with each other and communicate with the anterior twigs
of the Remus maxillaris (Fig. 114 Vc) and with those of the Ramus
palatinus (Fig. 113 V6).

In its course through the orbit the Ramus ophthalmicus gives
off :—

(1) Near the Gasserian ganglion < one, two, or three small branches,
which communicate with the trochlear nerve, and may then be
traced to the sclerotic of the eyeball ; some of the twigs enter near
the optic nerve, others nearer the cornea. They are regarded as
Ciliary nerves (Nervi cil.ares).

(2) A large branch, the palatine nerve (Ramus palatinus),
(Figs. 111 and 113 7,4). This nerve, after receiving the palatine
branch of the facial, descends on the inner border of the Levator
bulbi to the mucous membrane of the mouth, to which it gives
numerous filaments ; it then runs parallel and near to the median
line, lying on the base of the skull; and near the front of the
orbit it divides into three branches. The smallest (a) supplies
the Harderian gland (HD); the second (4) continues in the course

of the original nerve, pierces the vomer, and divides, giving
filaments to the mucous membrane in its whole course, while
the terminal twigs supply the intermaxillary gland (G7) and the
surrounding structures. One of these (¢) ascends on the anterior
border of the sphenethmoid to the intermaxillary (internasal,
Born) space to supply the numerous glands and to inosculate by
one or two twigs with the nasal branch (fr) of the trigeminal.

170 THE NERVOUS SYSTEM.

The third branch of the palatine nerve (c) curves directly out-
wards, just behind the palatine bone, to the inner surface of the
maxillary bone; it then courses backwards, pierces the fibrous
plate (db) between the eyeball and the pterygoid bone, and ulti-
mately unites with superior maxillary division of the trigeminal
nerve (Vc’). Just before piercing the fibrous plate it gives off a
tolerably large nerve (d) to the mucous membrane, and in its whole
course it gives off twigs to the mucous membrane and surrounding
structures; many of these twigs imosculate with other terminal
twigs of the trigeminal.

[This nerve has been minutely described by Stirling and Mac-
donald ; these observers find that the branches form a very fine and
close plexus in the mucous membrane, etc. ; fibres were traced to
blood-vessels, glands, etc., and ganglion cells were found scattered
along the nerves. The fibres are both medullated and non-medul-
lated, and many of the cells are described as ‘ spiral cells’ (see page
201), such as those described by Arnold in the sympathetic system
of the frog. ] .

b. The Ramus maxillo-mandibularis (Ramus manillaris, Ecker and
Hoffmann ; Supra-maxillary, Humphry; Upper Maxillary Branch,
Wyman), (Figs. 111, 112, and 113 Vc). This nerve is the largest
division of the trigeminal; it runs directly outwards behind the
eyeball, in front of the auditory capsule, and between the temporal
and pterygoid muscles. After a very short course it divides into the
maxillary and mandibular nerves. The nerve gives off before its
division a few fine filaments (7,7) to the hinder half of the upper
eyelid and to the surrounding skin, also a branch (4) [not correctly
drawn in Fig. 111] which divides to supply twigs to the temporal
and pterygoid muscles.

(1) The Ramus mawillaris (Ramus supramaxillaris, Ecker ; Ramus
maxillaris superior, Hoffmann ; Upper Maxillary Branch, Wyman ;
Supramaxillary, Humphry and de Watteville), (Figs. 111, 112,
113, and 114 Vc) runs outwards and then forwards, between the
eyeball and the outer wall of the orbit, to the margin of the upper
jaw (K); a large portion terminates in a number of small branches
for the supply of the skin of the lower eyelid, the upper lip, and of
the parts between the tympanic membrane and the external nares.
Some of these twigs inosculate with twigs of the palatine and
ophthalmic nerves. The second portion of the nerve unites with
the palatine nerve, as already described.

THE CRANIAL NERVES. 171

(2) The Ramus mandibularis (Ramus mazillaris inferior, Hoff-
mann; Mandibular or Lower Jaw Branch, Wyman ; Inframaxillary,
Humphry and de Watteville), (Figs. 111, 112, 113, 114, and 115
Vd, us). As far as the outer margin of the eyeball, this nerve
runs parallel to and behind the Ramus mazillaris, in which course it
supplies brariches to the temporal and pterygoid muscles ; it then
curves backwards, outwards, and downwards to the under surface
of the squamosal bone, where it supplies a twig to the Depressor
maxillae, and then perforates the Masseter: in this manner it
reaches the outer surface of the mandible, just behind the insertion
of the temporal muscle ; it then courses forwards, under the skin, to
the Symphysis menti. In this course the nerve gives off numerous
branches to the skin and surrounding parts, it also supplies the
mylo-hyoid and submental muscles; one branch (Figs. i114 and
115 us) is larger than the rest, and supplies the under surface of
the floor of the mouth and lower lip.

6. The abducens nerve (Nerrus abducens, Ecker and Hoffmann ;
included in the trigeminal, Wyman), (Figs. 111 and 112 V1). This
* very slender nerve courses along the inner wall of the cranium from
its origin to the Gasserian ganglion (q.v.) which it joins, and leaves
this in contact with the ophthalmic division of the trigeminal
nerve: the nerve then bifurcates in the orbit; the outer branch
supplies the Rectus externus, the inner inosculates with small twigs
of the ophthalmic division of the trigeminal, and then gives off
_ a number of small ciliary nerves, already described, and one special
_ branch to the Refractor bulbi.

7. The facial nerve (N. facialis, Ecker and Hoffmann ; Facialis
_ (Portio dura), Wyman ; Facial or Jugular Nerve, Stannius), (Figs.
111, 113, and 114 Ve VI) arises immediately behind the trige-
_ minal, and runs forwards, first in company with the auditory
nerve, then alone, to the Gasserian ganglion (q.v.), with which it

unites; it again appears at the posterior angle of the ganglion,

Sand escapes from the cranium in company with, and immediately

PS behind, the Ramus mandibularis of the trigeminal, and divides at

once into two branches.

a. The Ramus palatinus at once unites with the palatine
branch of the ophthalmic division of the trigeminal nerve.
Wiedersheim doubts this arrangement, and holds that the two
portions arise in common from the Gasserian ganglion; neither
has Wyman (Rana pipiens) described this branch of the facial.

172 THE NERVOUS SYSTEM.

[De Watteville states that the Ramus palatinus and the palatine
branch of the ophthalmic nerve are separated by the carotid artery.
In urodeles the two nerves are distinct. |

b. The Ramus hyomandibularis (Ramus jugularis, Hoffmann ;
Facial Nerve, Wyman), (Figs. 113 and 114, Ve VII). The nerve
is directed outwards and backwards so as to pass around the
bony wall of the auditory capsule, it then crosses over the inner end
of the columella, with which it is in close contact, and is then
joined, under cover of the s/erno-cleido-mastoideus (sc), by a branch
(Ramus communicans) of the glossopharyngeal (see Fig. 111 *). The
single trunk (/’) so formed is directed downwards in the posterior
wall of the Eustachian tube to just above the angle of the mandible,
where it divides into three branches, or sometimes into two, in
which case a third nerve is supplied by one of the others, usually
by the Ramus hyoideus.

(1) The Ramus mandibularis (Ramus mentalis, Hoffmann ; Third
Trunk of the Facial, Wyman), (Figs. 114 mt and 115 m’) passes inside
the angle of the jaw and courses forwards, between the skin and
mylo-hyoid muscle, parallel to the Ramus mandibularis of the
trigeminal nerve, as far as the symphysis. _ It supplies small twigs
to the neighbouring parts of the mucous membrane of the mouth.

(2) The Ramus hyoideus (Ramus jugularis, Hoffmann ; Second
Trunk of the Facial, Wyman), (Figs. 114,115 4) is the largest division
of the facial ; it courses forwards subcutaneously over the de/toideus
and the hinder fibres of the mylo-hyoideus to the anterior cornu
of the hyoid bone, supplying its muscles and the skin of the throat
and sternal region.

(3) The Ramus auricularis (First Trunk of the Facial, Wyman) ;
is a small branch, directed outwards ; it supplies a branch to the
walls of the tympanic cavity, and % finally distributed in the
skin under the tympanic membrane and behind the angle of the
mouth.

8. The auditory nerve (JV. acusticus, Ecker, Hoffmann ; Audi-
tory Nerve, Wyman). This nerve has a very short course in the
cranium; it reaches the auditory organ by a foramen (Fig. 116
VIII) in the auditory capsule, and is then distributed in the ear,
with which it will be described.

9. The glossopharyngeal nerve (N. glossopharyngeus, Ecker ;
Ramus glosso-pharyngeus, Hoffmann ; Glossopharyngeal, Wyman ;

THE CRANIAL NERVES. 173

Glossopharyngeal of the Vagus, Miiller), (Figs. 102 and 103 X, 111,
113, 114, and 115 X*) arises in common with the pneumogastric
nerve, and quits the skull with it through an opening (Canalis nervi
vagi) immediately behind the auditory capsule, and at once divides
into two branches ; both of which lie under the MM. intertrans-
versarii capitis and are covered by the Depressor mandibulae.

a. The Ramus anterior (Verbmdungsast des Glossopharyngeus,
Wiedersheim ; Ramus communicans, Hoffmann; Unitmg Branch,
Wyman ; Laryngeal Branch of the Vagus, Volkmann ; Communi-
cans ad facialem, de Watteville), (Figs. 111,113, and 114 X"). This
nerve curves downwards and forwards around the auditory capsule
and beneath the Depressor mandibuli to join the facial nerve, as
already described.

b. The Ramus posterior (N. glossopharyngeus, Wiedersheim ;
Ramus lingualis, Hoffmann), (Figs. 111, 113, and 114 X”). This
nerve runs downwards and forwards to the ventral surface of the
pharynx, dips underneath the Petrohyoideus IV, to appear again,
after a short imterval, by piercing the Petrohyoideus II or LI,
courses el to and behind the anterior cornu of the hyoid bone,

and thus reaches the floor of the mouth. The nerve then runs

forwards in a very sinuous course, close to the median line, and
between the Geniohyoideus and Hyoglossus; in its course on the
floor of the mouth it crosses the hypoglossal nerve. It supplies
the petrohyoid muscles, and gives numerous small branches to the
mucous membrane of the pharynx (Ramus pharyngeus, Hoffmann).

10. The pneumogastric or vagus nerve (Vagus; Ramus intestinalis
nervi vagi, Fischer, Hoffmann; Vagal Trunk, Wyman; Vaso-
sympathetic, Gaskell), (Figs. 111, 113, 114, and 115 X%). This
herve arises in common with the glossopharyngeal the two nerves

_ - leave the skull together by an opening in the exoccipifal bone

(Canalis nervi vagi); immediately outside the skull they acquire a
ganglionic enlargement (Ganglion condyloideum, Ganglion nervi vagi),
(Fig. 111 XG) ; in this course the glossopharyngeal lies in front of
the pneumogastric, which it then leaves. The pneumogastric lies
first upon the MW. levator anguli scapulae, then running backwards
and downwards along the hinder border of the Petrohyoideus IV
it comes to the side of the pharynx ; it is covered by the trapezius,
and passes between the hypoglossal nerve and the Aorta ascendens ;
arriving at the Arteria pulmonalis, it gives off its terminal branches.

174 THE NERVOUS SYSTEM.

[Gaskell has proved that this nerve contains both sympathetic and
vagal elements, and that it is therefore really a vago-sympathetic. |

The branches

Fig. 116. and communica-

tions of the pneu-

mogastric nerve

q are :—
E a. Communica-
Hf i \ tions between the
ganglion of the
Ea . Ss tee pneumogastric and

the sympathetic
system (Fig. 111
Sp), which again

iT Optic nerve.

III Motor oculi nerve. ~ connect it with

IV Trochlear nerye, :

VN Root of the trigeminal nerve. the Gasserian gan-

Vg __Gasserian ganglion. 7 j-

VS Sympathetic nerve. ‘ glion of the tri
VI Abducens nerve. geminal nerve

VIP Facial nerve. F

VIIT Auditory nerve. (Fig. iil VS, V9);
(1-3 i :

x Pneumogastric and glossopharyngeal nerves. (see sympathetic

system).

b. [The Ramus cutaneus dorsalis (Fischer) is considered by Stan-
nius and Fiirbringer to be the homologue of the Ramus auricularis ;
it passes outwards between the digastricus and temporalis to be
distributed in the skin of the suprascapular region. This nerve

is the persistent portion of the NW. dateralis nervi vagi of the
tadpole. |

ce. During its course over the petrohyoidei the vagus gives off a
few twigs (Fig. 114 pp), which form a fine plexus to supply these
muscles and the pharynx [also a twig to the trachea, according to
Hoffmann].

d. The Ramus accessorius (Fiirbringer, Hoffmann, Ecker), (Fig.
114 X/) is usually a single small nerve which runs between the
intertransversarit muscles and the trapezius: it supplies the under
surface of the latter muscle.

e. The Ramus scapularis (Hoffmann) is a very slender nerve arising
near the Ramus accessorius; it passes along the under surface of
the trapezius to the inner surface of the énterscapularis, which it
supplies.

THE SPINAL NERVES. 175

f. The Ramus laryngeus (Recurrens vagi), (Figs. 114 and 115
¥3/) runs for some distance parallel to the pneumogastric, separated
from it by the petrohyoideus IV; arriving at the hinder cornu of
the hyoid bone the nerve loops round the Arteria pulmonalis, and
divides into two branches for the supply of the larynx.

g. The Rami gastrici (Fig. 114 X39) are usually two in number :
they pierce the partial diaphragm formed by the anterior fibres of
the M. obliquus internus and terminate in the walls of the stomach.

h. The Rami pulmonales (Figs. 114 and 115 X3p) also perforate
the partial diaphragm, and then course along the pulmonary arteries
to the lungs. *

i. The Ramus cardiacus (Ries 114 and 115 X3c). This nerve
is usually smaller on the right side than on the left; it passes
along the dorsal surface of the pulmonary artery and Vena cava
superior to the Sinus venosus ; in this course it gives off two or three
twigs to the roots of the lungs: the two nerves communicate just
before reaching the heart and pass on to the auricular septum,
whence they are distributed to the heart.

j. A slender Laryngeal nerve arises from the vagus alongside
the Ramus cardiacus ; it courses along the hinder end of the greater
cornu of the hyoid to the outer side of the pharynx, which it

pierces to pass to the larynx.

F. Tue Sprvat NERvEs.

I. General description. Ten pairs of nerves arise, as already
described (p. 135), from the spinal cord; each nerve has two
roots, a ventral or anterior, and a dorsal or posterior, which unite
_ at their points of exit from the intervertebral foramen: just

before, and* for a short distance beyond this union, each dorsal

root bears a ganglionic enlargement.

1. The length and direction of the various Nerve-roots’ vary
greatly; the roots of the anterior spinal nerves run a very short
course, almost transversely outwards, from their points of origin to
the intervertebral foramina: the roots of the middle and posterior
nerves, in consequence of the vertebral column being considerably
longér, than that part of the cord belonging to it, pass obliquely
backwards to the foramina, the hinder nerves of the Cauda equina

running for a considerable distance in the vertebral canal (Fig. 116).
The relations of these roots are as follows :—

176 THE NERVOUS SYSTEM.

(1) The roots: of the first nerve (WV. Aypoglossus) arise from the
spinal cord at a point between the first and second vertebrae ; they
run transversely outwards to escape between the first and second
vertebrae. The dorsal root is extremely slender. ”

Fig. 117. * (2) The roots of
the second nerve (J.

The nervous system of Rana es-
culenta, from the ventral sur-
face. (From Icones physiolo-
gicae by A. Ecker. Pl XXIV,
Fig. 1.)

F Facial nerve.

G Ganglion of pneumogas-
tric nerve.

He Cerebral hemisphere.

Le Optic tract.

Lop Optic lobe.

M Boundary between me-
dulla oblongata and spi-
nal cord,

Mx-10 Spinal nerves.

MSC tion between fourth
spinal nerve and sympa-
thetic chain.

N Nasal sac.

Ni Sciatic nerve.

No Crural nerve.

0 Eyeball. —

8 Trunk of sympathetic.

S1-10 Sympathetic ganglia.

SM Rami communicantes of
the same.

Sp Continuation of sympa-
thetic into head.

I Olfactory nerve.

iI Optic nerve,

III Motor oculi nerve.

IV Trochlear nerve.

V Trigeminal and facial
nerves,

Va Ramus ophthalmicus.

Ve Ramus maxillaris.

Vd Mandibular “branch — of
trigeminal.

Ve Hyomandibular branch of
facial.

Vg _Gasserian ganglion,

Vs Upper end of sympathetic
trunk in connection with

Gasserian ganglion,
VI Abducens nerve,
VII Facial nerve. f

VIII Auditory nerve.

x Glossopharyngeal and
pneumogastric nerves.

X1 Ramus anterior of glosso-
pharyngeal,

X2 Ramus posterior of glosso-
pharyngeal.

X3, 4 Branches of pneumogas-
tric. ,

THE SPINAL NERVES. 177

—_—"

brachialis) arise at the level of the second vertebra and leave the
vertebral canal between the second and third vertebrae. °

(3) The roots of the third nerve arise from the cord between the
second and third vertebrae, and pass out between the third and
fourth vertebrae.

(4) The fourth nerve arises by its two roots at the level of the
fourth vertebra, and quits the vertebral canal between the fourth
and fifth vertebrae.

(5) The fifth nerve arises opposite the fourth vertebra, and passes
outwards and slightly backwards to the foramen between the fifth
and sixth vertebrae.

(6) The roots of the sixth nerve are attached to the cord opposite
the fourth vertebra, and leave the vertebral canal between the
_ sixth and seventh vertebrae.

(7) The seventh nerve arises from the cord at a point between
the fourth and fifth vertebrae, and leaves the canal between the
‘seventh and eighth vertebrae.

_ (8) The eighth nerve quits the cord at a point opposite the arti-
culation between the fifth and sixth vertebrae, then runs backwards
_ to the eighth vertebra, and escapes between this and the ninth
vertebra.
(9) The ninth nerve arises at the level of the sixth'vertebra, and
passes out between the sacrum (ninth vertebra) and the urostyle.
i (10) The tenth nerve (1. coccygeus) arises from the cord immedi-
_ ately behind the ninth nerve and opposite the sixth vertebra, and
_ courses alongside the terminal filament to pass out through a fora-
__ men in the urostyle (canalis coceygeus).

b. [The Spinal ganglia (Ganglia intervertebralia).

At their exit from the intervertebral foramen the two roots of
_ each nerve unite and bear a ganglionic enlargement, which is in
intimate connection with the dorsal root, but is merely in contact
_ with the ventral root. The ganglia lie’ in the large intervertebral
_ depressions, upon the under surface of the Proc. obligqui, above and
- behind, being in relation with the bodies of the vertebrae internally,

and the: Musculi intertransversarii externally (Fig. 119); ventrally
| the ganglia are, more or less, covered by the ‘ periganglionic glands.’
| The ganglia vary much in size ; that of the first spinal nerve is the
. 1 The Gangl. coccygeum is in the urostyle.

N

178 THE NERVOUS SYSTEM.

smallest. The ganglion is not attached to the dorsal root alone
but is prolonged a short distance beyond. the point of union of the
two roots ; this is best seen in the nerves of the lumbar plexus.
Each ganglion is a yel-
lowish-white rounded
or oval body, with an
outer thick (sometimes
o15 mm. thick) sheath
of connective - tissue,
connected by the epi-
neurium of the nerve
roots with the Dura

composed. of bundles of
parallel, wavy, white,
connective-tissue fibres,

number of connective-
tissue corpuscles, and
here and there contains
brown pigment.

By means of longi-
tudinal and transverse
sections it may be seen
that the ganglion sur-
rounds the ventral root,
but that it forms a
thinner layer on that
side, where the dorsal
root joins the ventral ;
although at this point
the two roots and the
ganglion are firmly uni-
ted together, the thick
fibrous sheath of the
ganglion prevents any
communication be-

Ventral view of the brain and spinal cord, to show the tween the nervous ele-
points of exit of the spinal nerves,

: ments of the ventral
Mrx-10 Spinal nerves.

VG@ Trigeminal ganglion. root and those of the
Wi-10 Vertebrae. ij
XG Ganglion of vagus. gangion.

mater. This sheath is”

‘which enclose a large -

:
;
F

THE SPINAL NERVES.

The sheath contains nerve-cells and

fibres, and sends in a few fine processes to
support these structures. The fibres of
the posterior root enter and pass out of
the ganglion without suffermg any

changes, except that the nerve fibres are ¢ |
slightly separated by the presence of a

few nerve-cells, and that a distinct in-

crease in the number of nerve fibres takes *

place. The nerve-cells, of which the
ganglion is chiefly composed, and upon
the number of which its size directly de-
pends, are arranged chiefly around the
fibres of the dorsal root; such few as
lie between the fibres are smaller than
the rest and vary more in their relative
numbers; at times one or two isolated
cells are found in the capsule or even in
the adjoining ‘periganglionic gland.’
The cells near the capsule are somewhat
smaller than the deeper cells!. Each of
these cells, which are usually pear-shaped,

possesses only one process ; the cell mem-
brane is thick, resistant, and possessed of

179

. Ventral view of the spinal ganglia ;

on the right side they are still
hidden by the ‘ periganglionic

an external nucleated, endothelial covering, the space around
being probably a pericellular lymph-space ; it often contains one to

three small fat-globules ; the protoplasm
of these has, according to v. Lenhossék,
a concentric fibrillation ; the nucleus is
round, clear, and distinct, and relatively
larger the smaller the nerve-cell; it is
. usually placed in the centre of the cell.
In that portion of the cell towards the
process is a portion brighter and less
easily stained than the rest of the cell
(Polarkernen, Courvoisier); this apparent-
ly possesses one or two nuclei, and is
regarded as a cell by Lenhossék (Polar-
zellen); the process of each cell soon
gia a medullated sheath, and after

Fig. 120.

Schema_of spinal ganglion.
Ventral root.

Ramus communicans.
Ganglion.

Dorsal division.

Dorsal root.

_ Ventral division.

' Larger cells of deeper — 80 » to go » in diameter, sometimes one or two as

large as c-t mm. v. Lenhoss¢k
N 2

180 THE NERVOUS SYSTEM.

a short course, o°og mm. to 0°35 mm., divides usually about the
third constriction (Lenhossék). These processes all pass peripherally,
even those which appear at first to pass in the opposite direction
curve round again ; it is chiefly due to these fibres that the spinal
nerve is larger than its two roots.

In addition to the above, smaller, irregular cells from 5 u to 7 p
in length are found; Rawitz regards them as young cells, Len-
hossék as cells capable of (entwicklungsfiihige) developing into
nerve-cells. The ganglia contain only few blood-vessels. |

The above description is founded upon that of Lenhossék, and
has been confirmed by the translator in every particular, except
that only very indistinct and unsatisfactory indications of the con-
centric fibrillation so clearly delineated by Lenhossék were obtained ;
the structure of the Gasserian ganglion was found to correspond
exactly with the description here given of the structure of the
spinal ganglia. The nucleus was oftener at the side than at the
centre of the cell.

ce. The ‘ Periganglionie Glands’ (Periganglioniire Kalkdriisen,
v. Lenhossék ; Kalksiickchen, Ecker, and others ; Crystal capsules,
Wyman ; Calcareous Sacs or Masses, of other writers), (Fig. 119).
These bodies are found on the ganglia of all the spinal nerves and
on the Gasserian ganglion of the trigeminal nerve; they have recently
been carefully investigated by v. Lenhossék. According to his
description there are usually two to each ganglion, lying on its
sides and ventral surface ; each consists of a connective-tissue cap-
sule which sends in a few fine trabeculae to support a system of
glandular tubes: these usually run parallel to the long axis of the
gland, and are about 14 » to 15 pw in diameter; each tube is lined
with a single layer of somewhat columnar epithelium, the cells of
which have sharp, distinct outlines and oval nuclei.

A membrana propria was not made out with certainty; the lumen
of the tubes is wide and contains a milky fluid, which gives the
whole structure its characteristic appearance; it has long been
known (Blasius, 1681, mentions the fact, /.c., p. 291) that this fluid
contains calcareous matter, which effervesces and dissolves in the
presence of hydrochloric acid ; the crystals vary in form but are
chiefly oval (Wyman). _

These glands bear no definite proportion to the size of the
nerves to which they are attached (Fig. 118); they already contain
calcareous matter during the tadpole stage before the limbs: are
developed (Stannius, Wyman). No ducts have been traced to

THE SPINAL NERVES. 181

these glands. This description, founded upon that of Lenhossék,
ean be confirmed by the translator in every particular ; his sections,
however, would lead him to believe that the glands are far more
vascular than the description and the drawings of Lenhossék

imply. |

d. The Branches of the complete spinal nerves formed by the
union of the dorsal and ventral roots with the ganglion (Fig. 120)
are usually described as two, a dorsal and a ventral branch, which
latter at once gives off a Ramus communicans to the sympathetic
system; these two branches are given off almost immediately
beyond the ganglion.

Il. The Individual Nerves.
A. The Dorsal Branches (Fig. 121).

The dorsal branches are smaller than the ventral; they pass up-
wards between the inner borders of the Muse. intertransversarii and
the articular processes of the vertebrae to reach the under surface
of the I. longissimus dorsi; the general course of these nerves is
very similar for all ; each nerve gives off-—

(a) A twig to the Muse. intertrans-
versarius and then divides into two
branches.

(2) A Ramus muscularis (Fig. 121
rm), which passes outwards to supply
the MW. longissimus dorsi. .

billy

ee

(c) A Ramus cutaneus (Fig. 121 re);
this nerve continues. under the ex-
tensor muscle of the back, running
on the arch of the vertebra towards
the middle line; it then pierces the
- muscle and Fascia dorsalis to reach
the large dorsal lymph-sae (Sace.
eranio - dorsalis), through which it
courses to end in the skin. In its
course through the sac the nerve is
connected with a small artery and gr xriprenabaies Vaueaaet, acne
vein’ by a small amount of connec- *™ te left side,
tive-tissue, the whole being enclosed ee! Sok i

182 THE NERVOUS SYSTEM,

in a sheath of endothelium continuous with that of the general
cavity.

The three anterior cutaneous nerves pierce the Fascia dorsalis near
the spinous processes, the fourth a little to the side, the fifth perfo-
rates the M. coccygeo-iliacus at about the junction of its anterior and
middle thirds; the sixth and seventh perforate the same muscle,
but more posteriorly. There are seven of these Rami cutanei, the
first coming from the second spinal nerve, the rest from the suc-
ceeding six spinal nerves.

B. The Ventral Branches.

The ventral branches of the spinal nerves are larger than their
corresponding dorsal branches: each nerve gives off immediately
a Ramus communicans to the sympathetic system (Figs. 117 SV,
120 C); these Rami communicantes will be described with the sym-
pathetic system ; the remaining portions of the ventral divisions of
the original spinal nerves are usually known as the spinal nerves ;
they will be described as such in detail.

_ 1, The hypoglossal nerve ! (NV. hypoglossus, N. spinalis I), (Figs.
114, 115, and 117 Mt), or first spinal nerve, is of small size; it
leaves the vertebral canal between the first and second vertebrae to
lie between the Musculi intertransversarii and the pharynx, where it
has in front the Arteria vertebralis, behind the Arteria and Nervus
brachialis ; passing under the Levator anguli scapulae; it touches the
Aorta ascendens and crosses the Vagus and the Carotid-gland, and
thus reaches the space between the Musculi sterno-hyoidei and the
Petro-hyoideus ; then curving forwards sharply it turns under the
Mylo-hyoideus to course between the fibres of the @enio-hyoideus to
the root of the tongue, where it ends. It first lies to the inner and
then to the outer side of the glossopharyngeal nerve. In its course
the nerve gives off the following branches :—

(a) One or two communicating twigs (Figs. 114 and 122) to the
second spinal nerve.

* [Observers have differed considerably as to the relations of this nerve : Volkmann
describes it as the first nerve of the neck, and describes a ganglion on its dorsal
root; Vogt denies the presence of this ganglion, and regards it as a true cranial
nerve; Stannius asserts that no ganglion exists, and holds the nerve to represent the
first two spinal nerves ; Wyman describes the two roots and regards it as a spinal
nerve ; Hoffmann regards this nerve as the second spinal (N. spinalis II): Fiir-
bringer as the representative of two spinal nerves; de Watteville describes two roots
and names it first spinal nerve.—TRANS. |

THE SPINAL NERVES. 183

(6) Muscular twigs to the Longissimus dorsi, Intertransversarii
capitis, Levator anguli scapulae, and the Retrahens scapulae.

(c) When near the glossopharyngeal it supplies twigs to the
Geniohyoideus, Sternohyoideus, and Omohyoideus, where it bifurcates.

-(d) One of the branches passes inwards to supply the Hyoglossus.

(e) The other terminal branch passes forwards with the Ramus
Hingualis and the glossopharyngeal, between the fibres of the Genio-
hyoideus, which it partially supplies, and sends twigs to the neigh-

(f) [Hoffmann describes a communicating branch to the pneu-
mogastric nerve, which the translator has not been able to discover,
and which no other observer has mentioned. |

2. The second spinal or brachial nerve (.V. brachialis, N. spinalis
IT), (Fig. 122) is a large nerve, leaving the vertebral canal between
the second and third vertebrae ; it then accompanies the Art. azil-
Jaris along the anterior border of the transverse process of the third
vertebra, over the hinder end of the Muse. levator scapulae and the
anterior end of the m. transverso-scapularis major, to the inner border
of the Musc. subscapularis, under which it passes into the arm. In
this course it gives off or receives the following branches :—

(a) It first receives a branch from the second spinal nerve.

(4) It gives off a large branch, the W. coraco-clavicularis (Fig. 122
Ce), which first accompanies a branch of the Art. axi//aris on the
Muse. levat. scapulae, then courses forwards and outwards over the

Musc. subscapularis to pass from above into the Foramen ovale be-

tween the clavicle and coracoid bones. It gives off two branches:

(1) One immediately beyond its origin, which runs backwards
over the Muse. subscapularis to supply the Muse. oblig. abdominis in-
__ ternus (Fig. 122 Cc’).

(2) While in the Foramen ovale, the N. coraco-clavicularis bifur-
cates ; the anterior twig runs forwards and outwards to the de/toideus
and also supplies a recurrent filament to the Musc. sterno-radialis ;
_ the posterior twig enters the upper surface of the Muse. sterno-
radialis.

___ (e) At the outer extremity of the Muse. transrerso-scapularis the
brachial nerve gives off a posterior branch, which at once bifurcates :

(1) The first branch passes into the under surface of the Muse.
latissimus dorsi (ld), giving a twig to the Infraspinatus.

(2) The second is the Ramus cutaneus axillaris (IIc) ; it passes on

184 THE NERVOUS SYSTEM.

the under surface and posterior border of the Muse. latissimus dorsi
to the skin of axilla and dorsal surface of the upper arm. :
(2) Several small branches are given off from the upper and an-
terior surfaces of the brachial nerve near the Foramen ovale ; they
accompany an artery to pass forwards and upwards between the
Muse. subscapularis and the M. transverso-scapularis on the one side,

Fig. 122.

The brachial plexus.

Ce N. coraco-clavicularis 5 ss Musc. subscapularis.

Ce’ Nerve to muse. obliq. abdom., internus. _SI_ First spinal nerve.

dad Deltoid muscle. : . SII Second spinal nerve.

la Muse. lev. ang. scap. ' SJIT Third spinal nerve.

id Muse. lat. dorsi, JTIe Ramus cutaneus axillaris.

ot Muse, obliq. abdom, intern. Ilfe Ramus cutaneus abdominalis.

sc Musc. sterno-mastoid.

and the long head of the W. triceps brachialis on the other, and are
lost in the MW. de/toideus and the M. infraspinatus.
_ The N. brachialis continues its course by passing between the
| long and inner heads of the W. triceps, reaches the arm and splits
‘ into two nerves, the WV. w/naris and the N. radialis.

[I.] The WV. wlnaris (Fig. 123 U) escapes from cover of the long
head of the M/. triceps and runs obliquely over its inner head

THE SPINAL NERVES. 185

towards the outer side of the Pica eubiti ; im this course it supplies
four branches :

a. The Ramus : solayadects — dorsally to the M.. suéb-
scapularis.

B. A Ramus pecto- Fig. 123.
vralis (Fig. 123, up),
passes forwards to the
M. abdomino-pectoralis
and to the skin of

the pectoral region (2.
~ entaneus pectoralis).

y- The NV. cutaneus
antibrachii superior 8
medialis (uc) passes
to the.skin of the

Nerves of the ventral surface of the arm. The hand pronated.

inner side of the fore- re Upper entaneous branch of the N. radialis.
z ; re’ Tower cutaneous branch of the N. radialis.
arm ; this and the Ot een
two following nerves ue R. cutan. sup. of the N. ulnaris.
- uc’ =R. eutan. inf. of the N. ulnaris.
are given off near the up R. pectoralis of the N. ulnaris.

Plica culiti.

8. The WN. cutaneus antibrachii inferior s. dorsalis s. musculo-
cutaneus (uc’) at once supplies branches to the MW. flexor cary radi-
alis1, and then runs downwards upon the muscle and bifurcates :—

[1] The R. /ateralis is distributed, by two twigs, in the W. flexor
carpi udnaris and in the skin of the second finger, to which it sup-
plies the Rami digitales rolaris and dorsalis.

[2] The R. dorsalis, after giving a cutaneous twig to the second
_ finger, is distributed by numerous twigs to the skin of the dorsal
_ surface of the hand.

The N. unaris then passes between the WV. flexor carpi radialis and
the tendon of the W. sterno-radialis, sinks deeply into the Plica
eubiti, where it lies between the WM. flexor carpi radializ and the
Flexor carpi ulnaris, then between the latter and the Fleror anti-
brachii medialis on the one side and the Flexor digitorum communis on
the other: it supplies branches to all these muscles, and while still
in the forearm divides into two terminal branches :-—

a. The “R. uluaris medialis is the smaller; it runs inwards,

* As this muscle increases in size during the breeding season, it would be inter-
esting to know whether a corresponding change takes place in the nerve.

Sa eae

186 THE NERVOUS SYSTEM.

passes under the tendon of the MW. extensor carpi ulnaris into the
palm of the hand and ends as the NV. volaris digiti V medialis.

B. The R. ulnaris lateralis
passes near the thumb-rudi-
ment, covered by the MW. aé-
ductor pollicis, deeply into the
palm of the hand, and supplies
by bifureating branches the
adjacent sides of the second,
third, fourth, and_ fifth fin-
gers (R. volares) ; it also gives
twigs to the muscles of the
palm. |

[1I.] The N. radials (Figs.
123, 124, and 125 FR) passes’

Nerves of the ventral surface of the arm, The hand immediately bey ond its cel Ad .
supinated, and the superficial layer (Flex. carpi rad. from the NV. brachialis, between

d uln., Flex. dig. .) has bee ed. ;
- SCN? CEE Sak ood the humerus and the IZ. triceps,
R N. radialis. er
uN, ulnaris. runs along the bone to its.

we Houma cftte Nes outer side; in this course it
gives off :—
a. Rami musculares to the separate parts of the M. triceps.
B. The Ramus cutaneus superior (Fig. 125 re) to the skin of
the outer surface of
the upper arm and fore-
arm.

Fig. 124.

Fig. 125.

The nerve then sinks
deeply under the origins
of the M. extensor carpi
ulnaris and the M. ex-
tensor digitorum commu-
nis, where it bifureates
after giving off some
small twigs :—

mae

y- Small muscular

The N. radialis. twigs to the extensor :
ec M. extensor carpi ulnaris. muscles of the hand and |
ed M. extensor digit. comm. }
RN. radialis. fingers. .
Rx R. lateralis. -

Re R. medialis. 6. The R. radials
re, cutaneus superior. > ee
re’ , cutaneus inferior. medialis (R2), the

a
P
a
a
:

THE SPINAL NERVES. 187

smaller terminal branch, supplies a branch to the MW. extensor digit.
comm. longus and the skin over the carpus (Ramus eutaneus inferior,
re’), and ends on the muscles of the little finger as the 2. dorsalis
digiti V medialis.

e. The 2. radialis lateralis (R), the larger of the two branches,
supplies the extensor muscles of the fingers and gives bifurcating
branches, Rami digitales dorsales, to the adjacent sides of the second,
third, fourth, and fifth fingers (the Ramus dorsalis lateralis of the
second finger is supplied by the NV. u/naris).

3. The third spinal nerve (J. spina/is III) (Fig. 122 SI1) leaves
the vertebral canal by the foramen between the third and fourth
vertebrae, and runs outwards and forwards upon the large transverse’
process of the third vertebra to the brachial nerve (J. spinadis II).
Its behaviour at this point is subject to considerable variation ; at
times it joims the brachial nerve completely, at other times the two
nerves are simply in contact ; or lastly, it may send a small twig
to the brachial nerve. Externally to this point the two nerves
supply a number of small branches, which may belong almost en-
tirely to either one nerve or the other ; these nerves again inosculate
in a variable manner, to form an axillary plexus. The more con-
stant branches are :— 4

(1) One or more twigs to the Vuse. transverso-scapularis major.

(2) Several branches, usually two larger and one smaller; they
course in the M. oblig. aldom. internus (Fig. 122 01) to the MW. rectus,
where they give off branches, then pierce the muscle to reach the
skin (R. eutaneus abdominalis), (Fig. 122 IIe).

4. The fourth spinal nerve (lV. spina/is IV) (Fig. 126 M4)
appears between the fourth and fifth vertebrae; it runs on the
ventral surface of the transverse process of the fifth vertebra and

upon the Muse. intertransversarius obliquely outwards and down-

wards, and reaches the deeper surface of the Muse. obliquus internus,
into which it descends, about opposite the articulation between the
eighth and ninth vertebrae ; it then bifurcates into :-—

(1) A Ramus cutaneus abdominalis, which pierces the muscle and
supplies the skin.

(2) A Ramus muscularis, which supplies the broad abdominal
muscle and the MW. rectus abdominis.

5. The fifth spinal nerve (J. spinalis V) (Fig. 126 M5) emerges
through the foramen between the fifth and sixth vertebrae, runs

188 THE NERVOUS SYSTEM.

obliquely downwards and outwards over the transverse processes of

the sixth and seventh vertebrae and the corresponding JZ. inter-
transversarii, and at a
point nearly opposite
the middle of the uro-
style pierces the WM.
obliquus internus,

The rest of its course
corresponds exactly
with that of the fourth
spinal nerve.

Fig. 126.

6. The sixth spinal
Nha at, EN 7 nerve (NV. spinalis V1)
Wi — (eee +S ie (Fig. 126 16), after

wer ae ii escaping from the ver-
gage if tebral canal between

the sixth and seventh
Lot vertebrae, runs ob-
Mer. liquely downwards and
5 i fem

outwards on the under
ws—-_ an Nia \ea surfaces of the trans-

(s sy ee verse processes of the
ee seventh, eighth, and
ninth vertebrae, then
under the iliac bone to
a point opposite the
hinder half of the uro-
style, where it descends
under cover of the J. -
obliquus abdom. internus.
In the rest of its course
it repeats the corre-
sponding courses of the
fourth and fifth spinal
nerves.

Ventral view of the brain and spinal cord, to show the

points of exit of the spinal nerves. 7, 8, 9, and10. The
Mx1-10 Spinal nerves. ' seventh, eighth ninth,
VG@ Trigeminal ganglion, “
Wx-10 Vertebrae. and tenth — spinal

XG Ganglion of the vagus, nerves (Nervi spinales

VII, VI, IX, and N. spinalis X 8. N. coccygens) (Figs. 426 and

4 ‘he ‘ig > i

: THE SPINAL NERVES. 189

127 M7, M8, Mg, and Mio) are best described together, as
they are intimately associated to form the sciatic plexus (Plerus
ischiadicus, Plexus cruralis).

Within the vertebral canal the roots of these nerves form the
Cauda equina; the seventh nerve leaves the canal between the
seventh and eighth vertebrae, the eighth nerve between the eighth
and ninth vertebrae, the ninth between the sacrum or ninth ver-
tebra and the urostyle, and the tenth by the Canalis coccygeus in
the urostyle ; from these points the four nerves run obliquely on
the ventral surface of the J/. ilio-coccygeus to the pelvis, where they
form the sciatic plexus. Although subject to some variation, the
usual arrangement is that the seventh and eighth nerves unite to
form a trunk, which then receives the ninth nerve ; the large nerve
so formed is the sciatic nerve: a branch of the tenth usually then
joins either the sciatic plexus or the sciatic nerve ; the plexus gives
off or receives the following branches :—

(a) Like other spinal nerves, these nerves give off Rami communi-
cantes (see Sympathetic System).

(4) The MM. clio-hypogastrieus (Fig. 127 M7ja). This arises from
the seventh spinal nerve, before its union with the eighth spinal
nerve ; it runs obliquely outwards and downwards on the Muse.
ilio-coccygeus and under the border of the MW. obliguus abdom. in-
ternus, where it bifurcates :— :

(1) One branch, the Ramus cutaneus abdominalis, pierces the
M. oblig. abdom. internus in the same ‘fashion as the cutaneous
branches of the fourth, fifth, and sixth spinal nerves; it supplies
the skin of the abdomen.

(2) The second or Ramus muscularis supplies the flat abdominal
muscles and the WM. rectus abdominis.

{¢) The MW. cruralis (Fig. 127 M7#) also arises from the seventh
spinal nerve at or just beyond its point of union with the eighth
_ spinal nerve. It accompanies the 4. cruralis on the pelvic wall to
_ the thigh, where it lies upon the W/. iZio-psoas in a triangle between
_ the W. rectus fem. anterior and the M. adductor longus, and divides

into two main branches :—

(1) Muscular twigs to the I. i/io-psoas, M. rectus femoris anticus,
MAM. adductores longus and brevis.

(2) The Ramus cutaneus femoris, which runs downwards in the
__ hinder wall of the Lymph-sae (Saceus iZiaeus), and supplies the skin
__ of the under and outer surfaces of the thigh.

190

THE NERVOUS SYSTEM.

(d) The Ramus dorsalis is a very small nerve ; according to
Waldeyer it possesses only twenty nerve-fibres. It arises from
Fig. 127. ;

SS

is vil

Is

$7

AZ

The sciatic plexus, from a drawing by Wiedersheim.

Communicating nerve from the ninth spinal
nerve.

Nerve to muse. lev. ani.

Nerve to oviduct.

Urostyle.

Communicating twig from the ninth spinal
nerve.

M. coccygeoiliacus.

M. coccy, i

Nerve to bladder.

Twig to the m. iliacus.

Twig from sciatic plexus to coceygeal plexus.

' M. intertransversarius.

M. ilio-coccygeus.

M. ilio-psoas, ‘
M. lev. ani.

M. obliq. abdom, internus.
Transverse process of sacrum.

‘

4

,

Ao
Com
Is
Ms
M6
M7

Rect’

Aorta.

Point of union of nerves a and ce.
Ischium.

Fifth spinal nerve.
Sixth spinal nerve.
Seventh spinal nerve.
Eighth spinal nerve.
Ninth spinal nerve.
Tenth spinal nerve.
M. iliohypogastricus.
M. cruralis.

Sciatic nerve.
Oviduct,

Rectum,

87,88, S89, Sxo Rami communicantes of seventh,

Ves
8,9

eighth, ninth, and tenth spinal nerves,
Bladder.
Eighth and ninth vertebrae.

:

THE SPINAL NERVES. 191

the coccygeal nerve immediately beyond the Canalis coccygeus,
perforates the M. i/io-coccygeus, and runs on its dorsal surface
obliquely over the lymph-heart, without supplymg it; the nerve
then pierces the fascia to supply the skin of the back and thigh.

(e) The Ramus abdominalis also arises from the coccygeal nerve ;

_ it is larger than the R. dorsalis, and arises at the same pomt; the

nerve runs on the ventral surface of the W. i/io-coccygeus towards the
lymph-heart, and inosculates with the sympathetic. It is from this
nerve that the branch to the sciatic plexus is usually given off ; it
further supplies a varying number of branches, which with branches
derived directly or indirectly from the sciatic nerve, form a plexus
(Plexus coccygeus) ; the two plexuses may together be regarded as a
Plexus ischio-coccygeus or a Plexus sacro-coccygeus.

(7) In addition to the Rami communicantes given off by the spinal
nerves near the vertebral column, the sciatic plexus supplies a few
twigs, usually two (Fig. 127).

(g) Other small twigs pass from the sympathetic system for-
wards and outwards to join the sciatic plexus or the sciatic nerve.
According to Waldeyer two of these are very constant.

(4) Branches to the oviduct (Fig. 127 4).

() Branches to the rectum (Fig. 127 ce).

(4) Branches to the bladder (Fig. 127 @).

(4) Branches to the W. /evator ani (Fig. 127 a’).

(m) A branch to the lymph-heart, which runs along the anterior

border of the J/. Zev. ani, on to its dorsal surface, and then direct to
the lymph-heart.

Variations in the sciatic plexus. The arrangement of the
nerves in the sciatic plexus is subject to many variations ; ac-
cording to Wiedersheim most of these variations belong to two
chief classes : either the NV. coccygeus mosculates directly with the
ninth spinal nerve by one or several branches, or it joins the ninth
nerve indirectly by uniting with its branches. A case of the
latter arrangement is seen in Fig. 127, and is thus described by
Wiedersheim :—

‘ After cutting through the pelvic symphysis and drawing to one
side the contained viscera, namely, the hinder end of the oviduct,
the rectum, and the bladder; one sees a row of small twigs (a, J,
ec, d, and e) arising from the inner, hinder, and anterior surfaces of
the ninth spinal nerve: the first (2) runs backwards parallel with

192 THE NERVOUS SYSTEM.

the NV. coccygeus over the M. itio-coccygeus to join this nerve at the
point marked Com. The twig ce behaves in like manner after re-
ceiving a twig from 6. The twig 4 arises from the inner surface of
the ninth nerve between the two foregoing and close to its union

with the eighth spinal nerve ; from this origin twig 4 passes almost.

transversely outwards to the hinder extremity of the oviduct
(“uterus ”’), and partly to the rectum, crossing in its course twig a,
the sciatic nerve, and the urostyle. Its branches form a net-
like plexus with the terminal branches. of the last sympathetic
ganglion and with a branch ce from the point of union Com.

‘A second branch (w’), arising from the point of junction Com, is
a continuation of the WV. coccygeus (M10); it passes vertically down-
wards towards the hinder end of the cloaca and at the upper border
of the Levator ani, divides into two branches, which are distributed
to the inner and outer surfaces of this muscle and to the cloaca.
Other branches pass dorsally to the lymph-hearts, while a third set
pass to the hindermost part of the bladder.

‘These three sets of nerves, to the MW. coccygeus, M. levator ani, —

and to the lymph-hearts, are not supplied entirely by the WN. coccy-
geus, as this is reinforced by one or more branches (e) from the
sciatic plexus: this branch (e) supplies twigs to the JZ. clio-coccygeus,
which is also supplied anteriorly from the trunk of the WV. coccygeus.

‘The bladder receives a special branch (d), which arises from the
sciatic plexus at the junction of the eighth and ninth spinal nerves ;
this nerve gives a twig (d’) to the MW. tdiacus,

I. The sciatie nerve (J. ischiadicus) (Fig. 128 J) is the largest
nerve of the body; it passes under the J/. coccygeus, between the
origins of the W/. vastus externus and of the MW. pyramidalis : lies then
between the MW. biceps and the M. pyramidatis, and later between the

M. biceps and the M. semimembranosus ; lastly, it bifureates under ~

the MW. biceps to form the N. tidialis (IT) and the N. peroneus (II/).
In this course it gives off :— a es

(a) A twig to the WM. coccygeo-iliacus, while still in the pelvis.

(6) The WV. cutaneus femoris posterior (Fig. 128, 2), which passes be-
tween the I/. pyramidalis and the M. vastus eaternus, to appear behind
and beneath the former ; it accompanies an artery of like name to

supply the skin of the hinder and inner surfaces of the thigh.
(ec) A little below the foregoing it gives off a collateral branch
(Fig. 128, 3), which passes under the /. pyramidalis and divides to
form—

a a

das icone meal aaa é

i en ter 2

THE SPINAL NERVES. 193
s

(1) A branch to the upper third of the M/. semimembranosus.

(2) A branch to the Rectus internus minor. A twig of this
branch (44) pierces the muscle transversely in company with the
Arteria cutanea, and passes to the skin of the middle of the inner
surface of the thigh. :

(3) Branches to both heads of the semitendinosus.
(4) Branches to the I/. adductor magnus.

(d) Branches covered by
the WM. pyramidalis to the
M. quadrat. femoris and M.
obturator.

(e) A branch (5) forwards
to the UW. biceps.

(f) A branch (6) which
accompanies the Art. circum-
jlexa genu lateralis sup. for-
wards to the MW. extensores
eruris, the M. vastus externus,
and the W. rectus anterior.

Distribution of the sciatic nerve.

I The sciatic nerve.

II N. tibialis.

Ill N. peroneus.

Branches to the M. pyramidalis.

N. cut. fem. posterior.

Large collateral branch.

Branch to the M. biceps,

Branch accompanying the art. cir-
cumfi. genn lateralis sup.

Branch of tibial nerve to the M. gas-
trocnemius.

M. biceps.
Twig accompanying the art. cutanea.
M. coceygeo-iliacus.

O29 4 ek Ue A 2 ANwW NW
m
i

194

THE NERVOUS SYSTEM.

II. The Nervus tibialis (Figs. 128 II, 129 7) passes backwards
and inwards to supply the extensors of the foot and the flexors of

the toes. Its branches are :—

(a) The R. cutaneus cruris posterior (Figs. 128 and 129 ct), ac-
companied by an artery and vein, passes to the skin of the calf.

(4) A twig to the upper part of the gastrocnemius (Fig. 129 9’).

Fig. 129.

The main nerve, after supplying
this twig, bifurcates to form the
next two nerves.

(c) The Nervus suralis. (Figs.
128, 8; 129 s) runs downwards
on the inner border of ‘the MW.
gastrocnemius and gives. off :—

(1) A twig (/”) to the upper
third of the muscle.

(2) The Ramus cutaneus me-
dius (cs) is given off below: the
middle of the MW. gastrocnemius ;
it passes to the skin of the

‘lower third of the leg. After

giving off the latter branch, the
N. suralis rons downwards along
the inner aspect of the Tendo
achillis to the Aponeurosis plan-
faris of the sole of the foot
as far as the calear, and gives

off :—

Nerves of the leg and sole of the foot.

abs Branch to the M. abduct. digit. V.
ads Branch to the M, adduct. digit. V.

ar M. rectus anterior,

b M. biceps.

cs Ramus cutaneus medius,

et Ramus cutaneus cruris posterior,

dvI Ramus digitalis volaris I.

dvIl_ Branch supplying R. digit. volaris I
and II.

dvIII Second branch of the N. tibialis.

Fs _ Branch to the M. flex. brev. digit. V.

flip ‘Branches to the M. plantaris and the
M. flexor digitorum.

g Branch to the M. gastrocnemius.
gf’ Branch to the M. gastrocnemius,
pe N. peroneus. o
3 N. suralis.

sm M. semimembranosus.
T,t Nervus tibialis.

Pa ee i a ne

“THE SPINAL NERVES. 195

--(3) Branches (7p) to the Muse. plantaris and the M. flexor
digitorum.

(4) A branch to the WM. abductor hallucis. ;

(5) The R. digitalis volaris I (dvI) supplies the inner side of the
first toe by its terminal twig.

(2) The Nervus tibialis (Fig. 129 ¢) passes downwards on the
hinder surface of the tibio-fibula, sinks into the MW. tibialis posticus
to appear again at its hinder border; it then runs over the ankle-
joint into the sole of the foot, where it lies midway in the space
between the two Ossa tarsi and between the W/. extensor tarsi and the
M. abductor digiti I longus ; the nerve then runs downwards in the
groove of the small Os ¢arsi and divides to form three branches :—

(1) The first branch (dvJZ) runs to the space between the second
and third fingers, where it bifurcates :—

(a) The Rami digital. volaris I ran transversely over the muscles
of the second toe, supply the muscles of the first toe, and bifur-
cate to form the R. digital. volaris I and IT.

(8) The Ram. digit. rolar. II divides in the space between the
second and third fingers to supply the Fler. phalang. and the adjacent
sides of these toes.

(2) The second branch (dvJZ/) runs over the M. flex. metatarsi of
the third toe to the space between the third and fourth toes, and
bifurcates to supply the adjacent sides of these toes and the web
between them.

(3) The third branch at once divides to supply :— i

(a) The WW. transv. metatarsi.

(8) The MM. lumbricales of the fourth toe.

(y) The M. abductor digit.V (abs), the M. flexor brevis dig. V
(F5), and the MW. adductor dig. V (ad5); it then ends as—

(6) A bifureating branch forming the R. digit. volar. of the fourth
and fifth toes.

III. The Nervus peroneus (N. peroneus communis superior, Ecker),
(Fig. 130 pe) is the second division of the sciatic nerve; it passes
between the outer head of origin of the MW. gastrocnemius and the

tendon of insertion of the Jf. biceps, it then lies on the tibio-fibula

between the W/. gastrocnemius and the MW. peroneus, where it is ac-
comnanied by the Vena tibialis postica, then runs downwards upon
the M. extensor cruris and the Fleror tarsi ant., and passes under
the M. tihial. anticus and bifureates ; its branches are :—

0 2

196 THE NERVOUS SYSTEM.

a. The NV. cutaneus cruris lateralis (Fig. 128 cp) ; which, like other
cutaneous nerves, runs in a common sheath together with an artery
and vein to the skin. It arises close to the sciatic nerve.

b. Muscular branches to the JM. peroneus, tibialis anticus, extensor
cruris brevis, and the flexor tarsi anterior.

Fig. 130.

Distribution of the NV. peroneus.

A Inner terminal twig of N. peron. comm.

inf.

B Outer terminal twig of N. peron. comm,

inf.
epl N. cutaneus dorsi pedis lateralis.
pe N. peroneus.
pei N, peroneus communis inferior
pl N. peroneus lateralis.
pm N, peroneus medialis,

e. The NV. peroneus medialis (Fig.
130 pm) is the smaller of the two
terminal branches of the NV. pero-
neus ; it courses with the Art. tibi-
alis antica under the MM. flexores
tarsi anterior and posterior and sup-
plies the latter.

d. The NV. peroneus lateralis (Fig.
130 p) is the larger terminal branch
of the WV. peroneus ; it passes down-
wards between the heads of the MW.
tibialis anticus to the tendon of origin
of the Flexor tarsi posterior, where it
gives off two branches (Nos. rand 2);
the nerve then unites with the J.
peroneus lateralis to form a common
stem, the NV. peroneus communis in-

ferior (Ecker). The NV. peroneus

lateralis gives off :—

(1) The N. cutaneus dorsi pedis

lateralis (cpl), which passes to the

skin of the outer side of the
dorsum of the foot.

(2) A second branch to the W. ex-
tensor of the fourth and fifth toes.

e. The NV. peroneus communis in-

ferior (Fig. 130 pct) runs on the

dorsum of the foot in company with
the Art. dorsalis pedis, underneath
the MM. extensores digiti I and I ;
it supplies several branches and then
bifureates. It gives off :—

(1) Branches to the JM. extensor
longus and brevis digiti I.

THE SYMPATHETIC SYSTEM. 197

(2) Rami digitales dorsales to the adjacent sides of the first and
second toes.

(3) Branches to the MM. extensores digiti LI.

(4) The inner, terminal branch (Fig.-130 4) at once divides :—

(a) The outer branch runs between the third and fourth toes as
far as the commencement of the web, where it bifurcates to form
two Rami cutanei, which course along the adjacent sides of these
toes as far as their apices.

(8) The inner branch passes to the extensor muscle, and, in part,
to the adjacent sides of the third and fourth toes.

(5) The outer, terminal branch (Fig. 130 B) of the N. peroneus
communis inferior passes to the muscles of the fourth and fifth toes,
and supplies Rami cutanei dorsales to the outer side of the fourth
and inner side of the fifth toes.

Cutaneous branches of the J. ¢idia/is supply the outer side of the
fifth and inner side of the first toe.

G. Tue Sympatuetic System (Sympathicus).
(Re-written by the translator.)

The sympathetic cord or chain is a row of nervous ganglia
(vertebral or lateral ganglia), connected by nerve-fibres, and lying
on either side of the vertebral column (Figs. 117 and 131); with
the exception of the last spinal nerve there is usually one sympa-
thetic ganglion associated with each spinal nerve ; in the case of the
tenth spinal nerve there may be only one ganglion or as many
as twelve.

The first ganglion (Figs. 111, opposite ics; 117 S1) is placed on
the hypoglossal nerve just as it emerges from the first intervertebral
foramen; it is large, but smaller than the second; its Ramus
communicans is represented by several fine and very short fibres,
which connect the ganglion with the nerve. This ganglion is con-
nected with the second by two or three nervous threads, between
which passes the subclavian artery, a true Aunuulus Vieussenii bemg
thus formed (de Watteville). The other ganglia are connected by
single bands of fibres. The first ganglion supplies also branches to
the axillary artery and to the cardiac plexus.

The second ganglion (Figs. 117 and 131) is the largest, and is
closely applied to the brachial nerve ; as in the case of the first
ganglion and hypoglossal nerve, it is attached to the second spinal
nerve without a distinctly marked Ramus communicans.

=

198 THE NERVOUS SYSTEM.

The third ganglion (Ganglion cardiacum basale, Gaskell and Gadow)
is sometimes fused with the second, but is usually close to the third
spinal nerve: it has a short but distinct Ramus communicans.
Behind the third ganglion the sympathetic cord is continued back-
wards along the corresponding aortic arch, then parallel with and
close to the abdominal aorta (Figs. 117, 127, and 131), receiving
Rami communicantes, which are
long and well marked, from
each of the spinal nerves ;
the fourth, fifth, and sixth
nerves usually supply each
one Ramus communicans, the
seventh two, and the eighth
and ninth each two or three :
from the tenth nerve it re-
ceives three or more, as many
as twelve having been noted.
The ganglia are usually more
or less spindle-shaped or flat-
tened and triangular; the
hinder part of the cord usually
receives in addition two or

_ three branches from the sciatic
plexus and twigs from the
R. abdominalis of the N.
coccygeus. °

The branches and commu-
nications of the sympathetic

Sympathetic cord. From Ecker (Icones physiologicae y
Pl. XXIV, Fig. 3). ’ cords are as follows :—
The heart, lungs, and liver have been removed ; the - :
stomach, intestine, kidneys, and testes drawn tothe a. Communicating branches

right side ; the left sympathetic cord is thus puled 3
to the right side to expose the Rami communicantes. between the two cords 5) these

S Sympathetic cord attached to the ganglion of the are extremely numerous and

vagus. ° : °
The numbers refer to the ganglia, which are enumer- irregular, forming me net-like
ated from before backwards. plexus 5 which surrounds the

abdominal aorta and other adjacent structures, and gives. off
numerous small twigs to the neighbouring vessels and organs.

b. Communications with the cranial nerves; these are two
branches (Wiedersheim), (Figs. 111 and 116) which pass from the
first ganglion to the Ganglion nervi vagi, where one terminates, the
other leaves the ganglion to pass on to the Gasserian ganglion

NR mime a
'

ee ee

THE SYMPATHETIC SYSTEM. 199

(Figs. 111 and 116 V8): apeording to Gaskell a single nerve passes
from the first ganglion to the Ganglion nervi vagi, whence one

portion of its fibres is continued to the Gasserian ganglion, the re-
mainder accompanying the pneumogastric nerve without. any con-
nection with the ganglion; he therefore names this nerve the
vago-sympathetic. (See Gasserian ganglion, p. 168.)

e. Communications with the spinal nerves ; these are :—

(1) The Rami communicantes.

(2) Communications between the sympathetic ganglia or their
branches and the spinal nerves or their branches (Fig. 117); by
means of these connections, fibres of the sympathetic system are
conducted by the spinal nerves and their branches to all parts of
the body.

da. Branches to the heart, which form the following ganglia :-—

(1) A relatively large plexus lies on the auricles in the median
plane immediately beneath the division of the MW. hyoglossus. It
supplies a network of fibres to the auricles and the adjacent large
vessels. It is said to communicate at various points with the
pheumogastric nerve.

(2) A smaller ganglion of oval form, supplies twigs te the
neighbouring vessels and a communicating branch to the hypo-
glossal nerve (Wiedersheim).

e. Branches to the abdominal viscera; these form intricate
plexuses by which the organs are supplied: the one best known
is the solar plexus (Fig. 131); it is formed chiefly from branches
derived from the third, fourth, and fifth ganglia, and supplies
the stomach, etc. ; other plexuses for the various viscera are known
by corresponding names, such are the Plerus hepaticus, renalis, geni-
talis, haemorrhoidalis, and vesicalis.

The sympathetic system is characterised by the fact that the
branches form intricate plexuses, which include numerous ganglia
and which are very irregular; it is also characteristic that most
of its fibres are non-medullated. According to the investigations.
of Gaskell, the fibres of the sympathetic system arise in mam-
malia as very fine medullated fibres from the posterior vesicular
(Clarke’s) columns (Mason has recently described cells in the
frog’s spinal cord, which he holds to be homologous with the cells
of these columns); they leave the cord by both the ventral and
dorsal roots of the spinal nerves, and are thus connected with two
sets of ganglia, (1) with the ganglia of the dorsal roots, and (2)

200 THE NERVOUS SYSTEM.

through the Rami communicantes with the sympathetic ganglia (ver-
tebral or lateral ganglia); these two sets of ganglia Gaskell terms
proximal. By means of the branches from the sympathetic ganglia
(Rami efferentes) part of the fibres pass to another set of ganglia, the
solar plexus, etc., which he terms prevertebral or collateral ; from
these the fibres pass to be distributed to the various viscera and blood-
vessels, where a fourth set of very small ganglia (terminal ganglia)
-isfound. The prevertebral and terminal ganglia are together classed
as distal ganglia. Gaskell holds that the fine medullated fibres
from the cord lose their medullary sheath in one or other of these
ganglia according to the function they fulfil.

The inhibitory fibres of the heart and vaso-dilator fibres of the
blood-vessels continue as white fibres along the vago-sympathetic and
spinal nerves to the distal ganglia (Bidder’s ganglion, etc.), where
the medullary sheath disappears: whereas the ‘augmentor’ fibres of
the heart and vaso-constrictor fibres of the blood-vessels lose their
medullary sheath in the proximal ganglia and pass on as non-
medullated fibres. In the same way the nerve-fibres that bring
about contraction of the circular muscle fibres of the hollow viscera
lose their medullary sheaths in the proximal ganglia, while those
fibres, the influence of which negatives the former, become pale
fibres in the distal ganglia.

Waters has demonstrated that in the frog the various spinal
nerves have each a localised physiological action upon the blood-
vessels and muscular walls of various parts of the alimentary canal :
he shows that

The third spinal nerve supplies the oesophagus.

The fourth spinal nerve supplies the stomach.

The fifth spmal nerve supplies the upper third of the small
intestine.

The sixth spinal nerve supplies the lower two thirds of the small
intestine.

The seventh spinal nerve supplies the large intestine. 5

The eighth spinal nerve supplies the bladder, this supply being,
however, not so definite as the others given above.

It has long been known that the branches of the spinal ganglia
(ganglia of the posterior roots) are together larger (one-third,
Lenhossék), and contain more fibres than the ventral and dorsal
roots together; this is supposed to be in part due to an acquisition
of new fibres derived from the ganglia. The majority of recent
observers hold that each ganglionic cell has only one process, which,

THE STRUCTURE OF THE NERVE-FIBRES SYSTEM. 201

however, soon bifurcates ; whether any of the fibres so formed pass
as far as the cord or beyond its blood-vessels is doubted by most ob-
sérvers, and denied by Gaskell. These remarks and the description
of the cells of the spmal ganglia (p. 176) hold good for the lateral
or vertebral ganglia and the prevertebral ganglia (solar gan-
glion, etc.) of the sympathetic system; the terminal ganglia will
be described with the organs in which they are found.

H. Histrotoeicat Nores oN THE Nervous System.

(in order to render the foregoing description of the nervous system more complete,
the following notes have been added by the translator.)

[The histological elements of the nervous system are nerve-cells
and nerve-fibres ; of these the nerve-cells have been deseribed with
the parts in which they occur; it may simply be remarked that
later observers have been unable to discover the ‘ spiral cells’ de-
scribed by Beale, Arnold, and others. The nerve-fibres, as in most
other animals, are of two kinds, medullated and non-medullated.

1. Medullated nerve-fibres or white fibres are found in all cranial
and spinal nerves, with the exception of the olfactory nerves, and
in many of the sympathetic nerves (see Sympathetic System) ;
also in the white matter of the brain and spinal cord; examined
microscopically the fibres are seen to consist of an external sheath or
neurilemma, a medullary sheath, and an axis-cylinder :-—

2. The neurilemma (Sheath of Schwann, Outer or Primitive
Sheath) is a nucleated endothelial layer covering the nerve-fibre ;
it is continuous with the corresponding coat of the nerve-cells, and
is uninterrupted throughout the length of the nerve ; at the nodes,
however, it dips down towards the axis-cylinder, the circular groove
so formed being filled with cement substance.

b. The medullary sheath (White substance of Schwann); the
presence of this sheath is the chief cause of the whiteness of these
nerves ; the thickness of the sheath varies considerably, and towards
the ultimate distribution of the nerve it is entirely lost. At more
or less regular intervals along the course of the nerve-fibre the
continuity of the medullary sheath is broken, and gives the
fibres the appearance of being constricted at these places; such
constrictions are known as nodes of Ranvier; the portion between
two such nodes being termed an internode. Each internode
possesses an oval, flattened, granular nucleus at about its middle

202 THE NERVOUS SYSTEM.

and placed between the neurilemma and the medullary sheath ; the .
nucleus has a nucleolus. In the fresh state the medullary sheath
seems to be fluid; it is of a fatty nature.

Medullary segments are caused by breaks in the continuity
of the medullary sheath, which are seen only in nerves which are
no longer in their normal condition, and are especially well marked
after treatment with osmic acid. ‘The breaks are oblique ; hence the
conical end of one segment fits into the funnel-shaped end of the next.
How far they correspond to pre-existent structures is uncertain.
The segments in the frog vary in length from o-o10 to 0°040 mm.

ec. The axis-cylinder is the essential part of every nerve-fibre ; it
shows a longitudinal striation corresponding to the fine fibrils
(primitive fibrillae) of which it consists; these fibrils often exhibit
minute varicosities: at times it has the appearance of being in-
vested with a very delicate structureless sheath. It is continuous
through the nodes of Ranvier.

2. Non-medullated nerve-fibres (Grey or Varicose Fibres ; Fibres
of Remak); these occur chiefly in branches and plexuses of the
sympathetic system; they consist of a neurilemma and an axis- ©
cylinder, which agree exactly with the corresponding elements
found in the medullated fibres.

The nerve-fibres, whether medullated or non-medullated, are
bound together by connective-tissue to form nerves. A number of
fibres bound together by connective-tissue to form a slender cord
is known as a funiculus ; a small nerve may consist of one such
funiculus ; the sheath surrounding it is known as the perineurium,
and sends in supporting processes between the fibres (endoneurium) ;
when several funiculi are bound together to form a large nerve the
common sheath is known as the epineurium. These sheaths support
nerves (zervi nervorum) and vessels (vasa vasorum) supplying the
nervous elements, and their intercellular spaces form lymph-canals.
The whole nerve is surrounded by an endothelial coat, which helps
to form a lymph-space, which more or less completely surrounds
the nerve.

The ultimate distribution of the nerve-fibres will be included in
the description of the various organs in which they end. ]

SECTION IV.

THE VASCULAR SYSTEM.

THE VASCULAR SYSTEM.

LITERATURE.

THE HEART AND BLOOD-VESSELS.

Aeby, Ueber den feineren Bau der Blutcapillaren. Centralbl. f. d. med. Wiss.
1865, p. 209.

Altmann, R., Ueber Corrosion in der Histologie. Centralbl. f.d.med. Wiss. 1878,
P- 245-

Aubert, H., Die Innervation der Kreislaufsorgane. Hermann’s Handbuch der
Physiologie. Leipzig, 1880. Vol. VI, Pt. I, p. 377.

Beck, K., Zur Kenniniss der Herznerven. Arch. f. mik. Anat.1884. Vol. XXIV,
pp. I1-I9.

v. Bezold, Untersuchungen iiber die Innervation des Herzens. Leipzig, 1863.

Bidder, F., Ueber functionell verschiedene und raumlich getrennte Nervencentra
im Froschherzen. Arch. f. Anat. u. Physiol. 1852, p. 163.

Bidder, F., Zur naheren Kenntniss des Froschherzens und seiner Nerven. Arch. f.
Anat. u. Physiol. 1866, p. 1.

Bidder, F., Endigungsweise der Herzzweige des N. vagus beim Frosche. Arch. f.
Anat. u. Physiol. 1868, p. 1.

Bidder, F., and Gregory, Beitrage zur Physiologie der Herzbewegung beim Frosche.
Dorpat, 1865.

Boas, J. E. V., Ueber den Conus arteriosus und die Arterienbogen der Amphibien.
Morph. Jahrb. 1881. Vol. VII, pp. 271-273.

Boas, J. E. V., Beitrage zur Angiologie der Amphibien. Morph. Jahrb. 1882.
Vol. VIII, pp. 169-187.

Bobretzky, C., Ueber die Entwickelung der Capillargefasse. Centralbl. f. d. med.
Wiss. 1885, p. 769. :

Bremer, L., Die Nerven der Capillaren der kleinen Arterien und Venen. Arch. f.
mik. Anat, 1882. Vol. XXI, p. 663.

Brenner, A., Ueber das Verhaltniss des N. laryngeus inferior vagi zu einigen
Aortenvarietaten des Menschen und zu dem Aortensystem der durch Lungen
athmenden Wirbelthiere iiberhaupt. Arch. f. Anat. u. Physiol. 1883, pp.
373-397-

Bricke, E., Ueber Mechanik des Kreislaufes des Blutes bei Friéschen. Wiener
Sitzungsb. 1851. Vol. VI, p. 61; also p. 114.

Bricke, E., Beitrage zur vergl. Anatomie u. Physiologie des Gefisssystems der
Amphibien. Denkschriften d. Wiener Academie. 1852. Vol. III, p. 335.
Burdon-Sanderson, J., Circulation of the Blood, in Handb. for the Physiological

Laboratory. London, 1873.

Burow, De vasis sanguiferis ranarum. Diss. inaug. Regiomontani, 1834.

Calori, L., Sugli organi della circulatione e della respirazione dei gyrini della Rana
esculenta e della Salamandra cristata. Nuov. Ann. delle Scienz. nat. de Bologna.
1838.

Champness, F., The Septum Atriorum of the Frog and the Rabbit. Journ. of Anat.
and Physiol. 1874, p. 340.

Chapmann, 8. H., Beitriige zur Kenntniss des Baues des normalen und entziindeten
Pericardiums der Batrachier. Wiener Med. Jahrbiicher.

” -
Sige

206 THE VASCULAR SYSTEM.

Chrzonzczewsky, N., Ueber die feinere Structur der Blutcapillaren. Virchow’s
Arch. 1866. Vol. XXXYV, p. 169.

Darwin, F., Contributions to the anatomy of the sympathetic ganglia of the Bladder
in their relation to the vascular system. Quart. Journ. Micros. Sci. 1874. Vol.
XIV, p. 109.

v. Deen, De differentia et nexu inter nervos vitae animalis et vitae organicae.
Diss. inaugur. Lugduni; also in Arch. f. Anat. u. Physiol. 1834, p. 477.

v. Deen, Over de zijelingsche Takken dar zwervende van den Proteus anguinis (in-
cludes frog-larva). Bijdragen tot de Naturkundige Wetenschappen, 1834.
Dogiel, J., Die Ganglienzellen des Herzens bei verschiedenen Thieren und beim

Menschen. Arch. f. mik. Anat. 1877. Vol. XIV, p. 471.

Dogiel, J., Die Nervenzellen und Nerven des Herzventrikels beim Frosche. Arch.
f. mik. Anat. 1882. Vol. XXI, p. 21.

Dumeril, A. M.C., and Bibron, G., Erpétologie générale, ou histoire naturelle com-
plete des reptiles. Paris, 1841.

Eberth, C. J., Ueber den feineren Bau der Blutcapillaren bei den Wirbelthieren.
Centralbl. f. d. med. Wiss. 1865, p. 196.

Eberth, Elemente der quergestreiften Muskelfasern, bes. des Herzens. Virchow’s
Arch, 1866. Vol. XXXVII, p. 100.

Ecker, A., Icones physiologicae. Leipzig, 1851-9.

Engelmann, T. W., Der Bulbus Aortae des Froschherzens. Physiol. Untersuch. in
Gemeinsch. mit. J. Hartog und J. J. Verhoff. Pfliiger’s Arch. f. d. ges. Physiol.
1882. Vol. X XIX, pp. 425-468.

Friedlander, Ueber die nervésen Centralorgane des Froschherzens. Unters. a. d.
physiol. Labor. in Wiirzburg. 1867. Vol. II, p. 159.

Fritsch, G., Zur vergleichenden Anatomie der Amphibienherzen, Arch. f. Anat.
u. Physiol. 1869, p. 654.

Gaskell, W.H., On the augmentor (accelerator) nerves of the heart of cold-blooded
animals. Journ. of Physiol. 1884. Vol. V, p. 46.

Gaskell, W. H., and Gadow, On the anatomy of the cardiac nerves in certain cold-
blooded animals, Journ. of Physiol. 1884. Vol. V, p. 362.

Gastaldi, Neue Untersuchungen iiber die Muskulatur des Herzens. Wiirzb.
Naturf. Zeitschr. 1862. Vol. III, pp. 6-9.

Gegenbaur, C., Grundztige der vergleichende Anatomie. 2nd edit., 1870.

Gerlach, L., Ueber die Nervenendigungen in der Muskulatur des Froschherzens.
Virchow’s Arch. 1876. Vol. LXVI, pp. 187-223.

Golubew, A., Beitrige zur Kenntniss des Baues und der Entwicklungsgeschichte der
Capillargefiisse des Frosches. Arch. f. mik. Anat. 1869. Vol. V, pp. 49-89.

Gompertz, C., Ueber Herz und Blutkreislauf bei nackten Amphibien. Arch. f.
Anat. u. Physiol. Phys. Abt. 1884, p. 242. Pe

Gruby, Sur le syst?me veineux de la grenouille. Annales des Sciences nat. 2rfl
series. Zool. 1842. Vol. XXVII, p. 207.

Gruby, Recherches anatomiques sur le syst#me veineux de la grenouille. Paris,
1842.
Geotisianen; R., Zur Lehre vy. d. Nervenendigungen in den glatten Muskelfasern.

Arch. f. mik. Anat. 1877. Vol. XIV, p. 321.

Heidenhain, Disquisitiones de nervis organisque centralibus cordis. Dissert. inaug.
Berol., 1854; and in Arch. f. Anat. u. Physiol. 1858, p. 479.

His, W., Ueber die Endigung der Gefassnerven (in mesentery). Virchow’s Arch.
1863. Vol. XXVIII, pp. 427-428.

Hoffmann, C. K., Die Lungengefiisse der Rana temporaria. Dissert. Dorpat,
1875.

rn hit C. K., in Bronn’s Klassen und Ordnungen des Thierreichs. Leipzig
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Hoffmann, T., Die Lungen-Lymphgefisse der R. temporaria. Dissert. Dorpat, 1875.

ee er Re ee ee ee

A

LITERATURE. 207

Huizinga, D., Untersuchungen iiber die Innervation der Gefasse in der Schwimmhanut
des Frosches. Pfliiger’s Arch. f. d. ges. Physiol. 1875. Vol. XI, p. 207.

Huschke, Ueber die Carotidendriise einiger Amphibien. Zeit. f. Physiol. von
Friedmann u. Treviranus. 1831. Vol. IV, p. 113.

Hyrtl,. J., Vorlaufige Anzeige tiber gefasslose Herzen. Wiener Sitzungsb. 1859.
Vol. XXXII, p- 572-

Hyrtl, J., Ueber die sogenannten Herzvenen der Batrachier. Wiener Sitzungsb.
1864. Vol. L, Pt. II, p. 42.

Hyrtl, J., Ueber das Verhalten der Leberarterie zur Pfortader bei Amphibicn u.
Fischen. Wiener Sitzungsb. 1864. Vol. XLIX, Pt. I, p. 167.

Jantschitz, J., Materialien zor Anatomie der Nerven des Pericardiums. Rudneff’s
Journ. f. normale und patholog. Histologic u, klinisch. Med. St. Petersburg,
1874, Pp. 417-442.

Klug, F., Ueber die Beschleunigungsnerven des Froschherzens. Centralbl. f.d. med.
Wiss. 1881, p. 945-

Klug, F., Ueber die Hermerven des Frosches. Arch. f. Anat. u. Entwicklungs-
geach. 1881, pp. 330-346. Abstract in Centralbl. f. d, med, Wim: 1882,
Pp- 259.

v. Kélliker, A., Handbuch der Gewebelehre. 5th edit.

Kiutiner, Beitrag zu den Kreislaufsverhaltnissen in der Froschlunge. Virchow’s
Arch. Vol. LXI, p. 21.

Lahousse, P., Die Structur des Nervenplexus in der Vorhofscheidewand des
Froschherzens. Arch. f. Anat. u. Physiol. 1886, pp, 191-196.

Lambotte, H. A., Observations anatomiques et physiologiques sur les appareils
sanguins et respiratoires de Batraciens anourés. Mém. cour I’ Acad. de Bruxelles.
1838.

Langer, C., Ueber das Lymphgefasssystem des Frosches. Wiener Sitzungsb. 1866.
Vol. LITI, Pt. I, p. 395; 1867. Vol. LV, Pt. I, p. 593; 1868. Vol. LVIII,
Pt. I, p. 198.

Langerhans, P., Notiz zur Anatomie des Amphibienherzens. Zeit. f. wiss. Zool.
1873. Vol. XXIII, p. 457.

Langerhans, P., Zur Histologie des Herzens, Virchow’s Arch. 1873, Vol. LVIII,
pp- 65-83.

Lavdowsky, M., Das Siugadersystem und die Nerven der Cornea. Arch. f. mik.
Anat. 1872. Vol. VIII, p. 538.

Lavdowsky, N., Ueber die Fortsiitze der Nervenzellen in den Herzganglien. Arch.
f. mik. Anat. 1887. Vol. X XIX, p. 609.

—— Ueber die Nervenendigungen und das Vorkommen von mikroskopischen
_Ganglien in den eT ee Zeit. f. wiss. Zool. 1864. Vol. XIV,
Pp- 346-352.

Levschin, Ueber taaiymeh: und Blutgefasssystem, Wiener Sitzungsb.1870. Vol.
LXTI, Pt. I, p. 67.

Leydig, Anatomisch-histologische Untersuchungen tiber Fische und Amphibien. 1853.

Leydig, F.. Ueber Organe e'nes sechsten Sinnes. Nova Acta Acad. Caes. 1868.
Vol. XXXIV, pp. 1-102.

Leydig, Lehrbuch der Histologie. 1857.

Léwit, M., Beitrage zur Kenntniss der Innervation des Herzens. Pfliiger’s Arch.
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‘p- 312. Chapter VII, 1882, Vol. X XTX, p. 469.

Léwit, M., Ueber die Gegenwart von Ganglienzellen im Bulbus aortae des
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88-94. a
Ludwig, C., Ueber die Herznerven des Frosches, Arch.-f. Anat. u. Physiol. 1848,
p- 139- 2

208 ; THE VASCULAR SYSTEM.

Marshall, A. M., The Frog. Manchester and London. 1885, pp. 22-31.

Marshall, C. F. Siteadbare and Distribution of striped and unstriped muscle. Quart.
Journ. ‘Niiseos. Sci. 1887. Vol. XXV. -

Meckel, J. F., System der vergleichenden Anatomie. Halle, 1833.

Milne-Mdwards, Legons sur la Physiol. et Anat. comparée. Vol. II, p. 407.

Namias, M., Suiganglii miocardici della Rana. Osservazione ed esperienzi in Lo
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Nicolsky, P., Ueber Flimmerendothel beim Frosche (in pericardium). Centralbl. f.
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Oellacher, J., Ueber die erste Entwickelung des Herzens und der Pericardial- oder
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v. Openchowski, T., Beitrag zur Kenntniss der Nervenendigungen im Herzen.
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Owen, R., Comparative Anatomy. Vol. I, p. 517.

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Pohl-Pincus, Ueber die Muskelfasern des Froschherzens. Arch. f. mik, Anat. 1884.
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Prévost and Lebert, Mémoire sur la formation des organes de la circulation et du
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Ranvier, L., Lecons d’anatomie générale. Paris, 1880, p. 469.

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Rawitz, B., Ueber den Bau der Spinalganglien. Arch. f. mik. Anat. Vol. XXI,
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Rosenberger, De centris motuum cordis disquisitiones anatomico-physiologicae.
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LITERATURE. 209

Schweigger-Seidel, Das Herz, in Stricker’s Handbuch d. Gewebelehre.

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Stirling, W., and Macdonald, The minute structure of the palatine nerves of the
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Stricker, S., Untersuchungen iiber die capillaren Blutgefasse in der Nickhaut des
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Stricker, S., Studien iiber den Bau und das Leben der capillaren Blutgefasse. Wiener
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Trevianus, G. R., Ueber die Karotidendriise einiger Amphibien. Tiedemann’s
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Trevianus, C. R., Beobachtungen aus der Zootomie u. Physiologie, nach dessen Tode
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Verhoeff, J. J. W., Histologische en physiologische bijdragen tot de kennis van den
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Vignal, Recherches sur l’appareil ganglion nerve du cceur des vertébrés. Labratoire
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Virchow, H., Ueber die Kopfgefiisse des Frosches. Sitzungsb. Wirzburg, 1880.
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Virchow, H., Ueber die Gefiisse im Auge und die Umgebung des Auges beim
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Volkmann, Nack:weise der Nervencentra, von welchen die Bewegung der Lymph-
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Wagner, R., Lehrbuch d. vergleichenden Anatomie. Leipzig, 1834-35.

Wagner, R., Icones Zootomicae. Leipzig, 1841.

Weismann, Ueber die Muskulatur des Herzens beim Menschen und in dem
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Wyman, J., On the heart and respiration of the Menobranchus and Batrachians.
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Zimmermann, W., Ueber circumvasale Saftriume der Glaskérpergefiisse von Rana
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THE LYMPHATIC SYSTEM.

Bacculo, B., Nuove ricerche intorno l’apparecchio ganglionare intrinsico dei cuori
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Eckhard, C., Zeitsch. f. rat. Med. 1850. Vol. IX.

Eckhard, C., Beitrige zur Anat. u. Physiol. 1855, Vol. I, p. 53; 1858, Vol. II,
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Goltz, Centralbl. f. med. Wiss. 1863, pp. 17, 497; 1864, p. 690.

Heidenhain, Disquisitiones de nervis cordis cordiumque lymphaticorum. Berlin,
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His, W., Ueber die Wurzeln der Lymphgefiisse in den Hiiuten des Kérpers und tiber
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Hoffmann, T., Die Lungen-Lymphgefasse der R. temporaria. Dissert. Dorpat,
1875.

Hiiter, C., Ueber den Kreislauf und die Kreislaufsstérungen in der Froschlunge.
Centralb. f. med. Wiss. 1873, Nos. 5 and 6.

As

210 THE VASCULAR SYSTEM.

Jourdain, 8., Sur les sacs sous-cutanés et les sinus lymphatiques de la région
céphalique dans la Rana temporaria. Compt. rend. 1881. Vol. XCIII, pp.
597-600.

Jourdain, S., Sur le syst?me lymphatique des tétards de grenouilles. Compt. rend.
1883. Vol. XCVI, pp. 271-273.

Jourdain, S., Recherches sur le systtme lymphatique de la R. temporaria.
Montpellier, 1883 ; Extr. de la Revue de Sci. nat. Montpellier, 1884.

Kahrhel, G., Studien iiber Innervation der Lymphherzen. Medic. Jahrb. 1886,
PP: 392-420.

Key and Retzius, Studien in der Anatomie des Nervensystems. Arch. f. mik. Anat.
1873. Vol. IX, p. 308.

Klein, E., On the lymphatic system of the skin and mucous membranes. Quart.
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Langendorff, O., and Boll, F., Zur Kenntniss der Lymphherzen. Arch. f, Anat. u.
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Langer, C., Ueber das Lymphgefiisssystem des Frosches. Wiener Sitzungsb. 1866,
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p- 198.

Levschin, Ueber das Lymph- und Blutgefiisssystem. Wiener Sitzungsb. 1870. Vol.
LXI, Pt. I, p. 67.

Luchsinger, B., Zur Lehre der Innervation der Lymphherzen. Pfliiger’s Arch. f. d.
ges. Physiol. 1880. Vol. XXIII, p. 304.

Meyer, J., Systema amphibiorum lymphaticum. Diss. Berol., 1845.

Miller, J., Beitrage zur Anatomie und Naturgeschichte der Amphibien. Tiedemann’s
Zeitschr. 1831. Vol. IV, pp. 190-275. :

Miller, J., On the existence of four distinct hearts having regular pulsations con-
nected with the lymphatic system in certain amphibious animals. Phil. Trans.
1833. Pt.I, pp. 89; also in Arch. f. Anat. u. Physiol. 1834, p. 296.

Miller, J., Bemerkungen iiber die Structur der Lymphherzen und der Lymphgefasse.
Arch. f. Anat. u. Physiol. 1839, p. 176.

Obersteiner, H., Ueber einige Lymphriume im Gehirne. Wiener Sitzungsb. 1870.
Vol. LXI, Pt. I, p. 57.

Pagliani, Ueber die Funktion der Herzganglien. Moleschott’s Untersuchungen.
1876. Vol. XI, p. 358.

Panizza, B., Sopra il sistema linfatico dei retelli. Ricerche Zootomiche. Pavia,
1833.

Panizza, B., Ueber die Lymphherzen der Amphibien. Arch. f. Anat. u. Physiol.
1834, p. 300.

Pihlermann, R., Untersuchungen iiber dié angeblich praiformirten Verbindungswege
zwischen den Blut- und Lymphgefissen des Frosches. Dissert. Dorpat, 1876.

Priestly, J., An account of the anatomy and physiology of the batrachian lymph-
hearts. Journ. of Physiol. 1878. Vol. I, p. 1.

Ranvier, L., Appareils nerveux terminaux des muscles de la vie organique; cceurs -

sanguins, cceurs lymphatiques; cesophagus ; muscles lisses. Lecons d’ Anatomie
générale faites au Collége de France. Paris, 1880. Vol. VII, p. 350.

v. Recklinghausen, Die Lymphgefasse und ihre Beziehung zum Bindegewebe.
1862.

Remak, R., Ueber blutlehre Gefasse (Lymphgefiisse) im Schwanze der Froschlarve.
Arch. f. Anat. u. Physiol. 1849, p. 102.

Robinson, C., Ueber die Lymphgefasse der Abdominaleingeweide der Frische,
sowie deren Lymphbehiilter. Froriep’s Notizen, 1846. No. 807, col. 225.

Rusconi, M., Lettre du docteur Rusconi ’ M. Breschet sur le systeme lymphatique
dela Salamandra commune Arch. f. Anat. u. Physiol. 1840, p. 8.

Rusconi, M., Ueber die Lymphgefisse der Amphibien. Arch. f. Anat. u. Physiol.

1843, p. 241.

LITERATURE. 211

Rusconi, M., Einige historische Notizen die Lymphgefisse der Amphibien betreffend.
Arch. f. Anat. u. Physiol. 1843, p. 244.

Rusconi, M., Sur les vaisseaux lymphatiques. Annales des Sci. nat. Series II. Zool.
1841. Vol. XV, p. 249-

Rusconi, M., Rifiessioni sopra il sistema linfatico dei Rettili. Pavia, 1845.

Scherkey, M. L., Ueber die Feststellung und Bedeutung der Centren der Lymph-
herzen im Riickenmark. Dissert. Berlin, 1878.

Scherkey, M. 1.., Zur Lehre der Innervation der Lymphherzen. Arch. f. Anat. u.
Physiol. 1879, p. 227.

Schweigger-Seidel, F., and Dogiel, J., Ueber die Peritonealhéhle bei Fréschen
und ihren Zusammenhang mit dem Lymphgefiasssysteme. Arbeiten aus d.
physiol. Anstalt. Leipzig, 1867, pp. 68-76; Abstract in Centralbl. f. d. med.
Wiss. 1867, p. 287.

Suslowa, N., Beitrige zur Physiologie der Lymphherzen. Centralbl. f. d. med. Wiss.
1867, p. 832.

Suslowa, Beitrage zur Physiol. der Lymphherzen. Dissert. Ziirich, 1867; also in
Zeitsch. f. rat. Med. 3rd series. 1868. Vol. XXXI, p. 224.

Waldeyer, W., Anatomische und physiologische Untersuchungen iiber die Lymph-
herzen der Frische. Zeitsch. f. rat. Med. 3rd series. 1864. Vol. XXI,
pp. 103-124 ; Abstract in Centralbl. f. d. med. Wiss. 1864, p. 73.

Waldeyer, W., Zur Anatomie und Physiologie der Lymphherzen von Rana und
Emys europea. Studien des physiol. Instituts zu Breslau. 1865, pp. 71-96;

Abstract in Centralbl. f. d. med. Wiss. 1865, p. 321.

Weber, E. H., Ueber die Lymphherzen der Amphibien von Panizza. Arch. f.
Anat. u. Physiol. 1834, pp. 300-304.

Weber, J., Beitrage zur Anatomie und Physiologie. Bonn, 1832.

THE BLOOD AND LYMPH.

Aly, W., Ueber die Vermehrung der rothen Blutkérperchen bei Amphibien.
Dissert. Halle, 1884.

Arndt, R., Beobachtungen an roten Blutkiérperchen der Wirbelthiere. Virchow’s
Arch. Vol. LX XVIII, p. 1.

Beale, L. 8., Observations upon the nature of the red blood-corpuscle. Quart.
Journ. Micros. Sci. 1864, pp. 32-43.

Bizzozero, G., Ueber die Teilung der roten Blutkérperchen. Centralbl. f. d. med.
Wiss. 1881, p. 129.

Bizzozero, G., Ueber die Teilung der roten Blutkérperchen. Centralbl. f. d. med.
Wiss. 1882, p. 577.

Bizzozero, G., and Torre, A. A., Ueber die Entstehung der roten Blutkérperchen
bei den verschiedenen Wirbelthierklassen. Virchow’s Arch. 1884. Vol. XCV,
pp- I-25-

Briicke, E., Ueber den Bau der rothen Blutkérperchen. Wiener Sitzungsb. 1867.
Vol. LVI, Pt. IT, pp. 79-91.

Donders and Moleschott, Hollindische Beitriige. 1848, p. 361.

Eberth, C. J., Ueber die Vermehrung der rothen Blutkérperchen nach Unter-
suchungen von W. Aly. Fortschritte d. Med. 1885. Vol. III, pp. 1-7.

Fuchs, E., Beitrag zur Kenntniss des Froschblutes und der Froschlymphe.
Virchow’s Arch. 1877. Vol. LXXI, p. 78.

Gaule, J., Beobachtungen der farblosen Elemente des Froschblutes. Arch. f. Anat.
u. Physiol. 1880, pp. 375-392.

P2

212 THE VASCULAR SYSTEM.

Gulliver, G., Measurements of the red blood-corpuscles of Batrachians. Proc.
Zool. Soc. London, 1873, p. 162.

Hewson, W., On the figure and composition of the red Particles of the Blood, com-
monly called Globules. Phil. Trans. 1773. Vol. LXIII, Pt. I, p. 303.

Home, E., On the changes the blood undergoes in the act of coagulation. Phil.
Trans. 1818, p. 172.

Kollmann, J., Bau der rothen Blutkérperchen. Zeitschr. f. wiss. Zool. 1874. Vol.
XXIII, p. 462.

Kusnezoff, F., Ueber blutkérperhaltige Zellen der Milz. Wiener Sitzungsb. 1873.
Vol. LXVII, Pt. ILI, pp. 58-67.

Moriggia, A., Ueber den Durchtritt der farblosen Blutkérperchen durch die Blut-
gefasswandungen, etc. Moleschott’s Untersuchungen. 1876. Vol. XI, p. 47¢.

Neumann, E., Zur Histologie der rothen Blutkérperchen. Centralbl. f. d. med.
Wiss. 1865, p. 481. _

Owsjannikow, P., Zur Histologie der Blutkérperchen. Bullet. de Pacad. science
de Pétersbourg. 1865. Vol. VIII, pp. 561-572.

Peremeschko, Ueber die Theilung der rothen Blutkérperchen bei Amphibien.
Centralbl. f. d. med. Wiss. 1879, pp. 673-675.

Ranvier, L., Traité technique d’histologie, pp. 148-224.

Rollett, A., Versuche und Beobachtungen am Blute. Wiener Sitzungsb. Vol.
XLVI, Pt. IT, pp. 65-98.

Stricker, Beobachtungen iiber die Entstehung des Zellkernes. Wiener Sitzungsb.
1878. Vol. LXXVI, Pt. 1IT, p. 7.

Thoma, R., Die Ueberwanderung farbloser Blutkérperchen von dem Blut in das
Lymphgefiisssystem. Heidelberg, 1873.

Welcker, H., Grisse, Zahl, Volum, Oberfliiche und Farbe der Blutkorperchen bei
Menschen und Thieren. Henle u. Pfeuffer’s Zeitschr, 1864. Vol. XX,
pp. 258-307. ;

~

a

PART I.
THE HEART AND BLOOD-VESSELS.

I THE HEART.
(The original arrangement of this section has been modified.)

Tue heart is situated in the middle line above the central portion
of the shoulder-girdle and WM. sternohyoideus, and below the
oesophagus ; the apex is directed backwards and lies between the
lobes of the liver, the base is directed forwards and lies a short
distance behind the larynx. The heart is surrounded by the

A. The Pericardium [is a
very thm membranous ac,
which completely encloses the
heart ; itis attached, at some S’>-
distance, to the large vessels BO

passing to and from the heart, ale ar
and has inserted into it some #4---—~ 3 FA lias ;
fibres of the M. obliquus ab- Ta.---------- SY) =a

dominis internus (see page 70).
A fold of the pericardium
extends fromthe dorsal sur-

face to the truneus arteriosus,
and through it courses the
vena cardiaca.
The pericardium is a con-
nective-tissue membrane, and ™°"** Rag ep erases ee

is lined on either side with
endothelium, which is in part
ciliated (Leydig); the endo-
thelium of the inner surface
is continued on to the heart

SPRERERA
:

214 THE VASCULAR SYSTEM,

and so forms a closed lymph-sae. The pericardium is more or less
pigmented, and contains both vessels and nerves ; it may contain
fat-cells].

B. The Heart.

[The heart is a hollow muscular organ, composed of: (1) two
auricles, forming the wider anterior portion ; (2) the ventricle, placed
behind the auricles ; (3) the sinus venosus, situated dorsally; and (4)

the truncus arteriosus, lying ventrally. Examined while still living, ~

the auricles are seen to be much darker in colour than the ventricle,
due to the blood being seen through their thinner walls; between
the auricles and ee ventricle is a distinct groove, ‘the auriculo-
ventricular groove. The whole organ is more or less pigmented,
especially the ventricle (2. temporaria has much less pigment). |

Big. 133- : a. The Sinus venosus
(Sinus venarum cavarum), (Fig.

133 SV.) is a thin-walled sae

of the heart, and very shghtly
to the right side (Hoffmann).
It is somewhat triangular in
form, receiving an anterior
caval vein at each anterior
angle (/.), and the posterior
caval vein (JC.) at the poste-
riorangle. The ventral wall
has a transverse opening (S/”.),
by which it communicates with

: = Z . _—~
ret the night auricle ; the opening
The heart, seen from above, and dissected to showthe possesses two valves, an ante-
opening from the Sinus vencsus to the right auricle ; ri or and a p ost eri or, an d is
after Howes.

@’. Right carotid arch. placed close to the auricular

IC, _ Posterior caval vein.
LA, ° Left auricle. septum.
P’. Right pulmo-cutaneous arch. 3
PV. Pulmonary vein. b. The auricles [are not
RA. Right auricle. i"
8S’. Right systemic arch, alway: 8 separated, a the sep
SV. Sinus venosus. - tum: which usually brings about
SV’. Opening of Sinus venosus into the right 2 Soar

auricle. the separation is in some cases
Ez Right anterior caval vein,

incomplete, and in rare in-
stances appears to be absent (Hoffmann)]; according to Ecker, the
auricular septum is sometimes placed so far to the left side that it

lying on the dorsal surface,

Ce me

Paar

>

THE

appears to be absent (Fig. 135).
The septum is attached to the
walls of the auricles so as to
form two distinct cavities, which
communicate at the auriculo-
ventricular opening, where the
septum -has a free concave

border (Fig. 134). The right

ace aay paral
] and receives the systemic
venous blood from the sinus
venosus by the opening (Figs.
133 and 134 SV.) already de-
scribed. The left auricle re-
ceives the blood from the lungs
by the pulmonary vein (Fig.
133 PF.), which opens into the
auricle near the septum (Fig.
134 PY.): [the openings from

the sinus venosus and from

the pulmonary vein may be so
closely approximated as to be >
separated by the septum only. ™

The septum is much thinner PY.
than the auricular walls]. Both rial

auricles open into the ventricle

ing (Fig. 134).

HEART.

215

The frog’s heart seen from the ventral surface, and

A,
B.

vee

Pe

8.

dissected so as to show its structure. The ven-
tral walls of the truncus arteriosus and of the
auricles and ventricle have been removed. From
a drawing by Mr. Hurst.

Auriculo-ventricular aperture and valve.
Aperture leading from ventricle to truncus

Left pulmo-cutaneous arch.
Style passed down right pulmo-cutaneous arch
into the truncus arteriosus, T.

SA. Septum atriorum.
SV. Opening of Sinus venosus into right auricle.
by the auriculo-ventricular open- ¥- Ventricle.

ec. The ventricle (Figs. 132, 134, and 136 V.), examined while

still livmg, is seen to be bluntly conical in
shape and darker on the left side than on the
right; this is due to the ventricular wall of
the right side, near the truncus arteriosus, being
somewhat thinner. The inner wall is not smooth
but possesses muscular ridges (Zrabeculae). At

Fig. 135.
Vv

its base the ventricle communicates with the’ pisection of a case in

auricles by the auriculo-ventricular opening
and with the truncus

(Figs. 134 and 436),

which the auricular
septum is placed more
to the left than is nor-

arteriosus by a separate opening (Fig. 134 B.). oes:
The ventricle is lined by a layer of odo SS Left auricle,

endothelium. -

V Opening into the -

Sinus venosus.

ies

216 THE VASCULAR SYSTEM.

The auriculo-ventricular opening (Fig. 134 A.) is a large
aperture guarded by two valves, a dorsal and a ventral: each valve
Fig. 136. is formed by a redupli-

LA. cation of the endothe-
“ lium, and contains a
small amount of con-

AC yh

TC; 3 5 R
” nective-tissue.; its free
RA.__ margin is bound down
by a» number (about
twelve) of fibrous cords,
the chordae. tendineae,
which are attached by
\ their posterior extre-
A V. - mities to the _ trabe-
Dissection of the heart from the left side ; after Howes, culae.
A, Auriculo-ventricular opening. d. The truncus ar-
AC, Anterior caval veins. A
IC. Posterior caval vein. teriosus(Figs. 132 7'A.,
LA, Left auricle. .
PV. Pulmonary vein. 134 A.) arises at the
RA, Right auricle. base of the ventricle,
SV. Sinus venosus. ; é .
TA, Truncus arteriosus, on the night side of
& Ventricle.

its ventral surface, then
passes forwards and to the left, across the auricles, to reach their
anterior border near the median line, where it divides to form two
vessels.

Internally it is incompletely divided into two compartments by
a spiral valve (Fig. 134); the valve is attached to the dorsal surface
and is free ventrally : when the vessel is fully dilated (artificially),
the valve extends two-thirds of its diameter. The opening of the
vessel into the ventricle is guarded by two semilunar valves (Fig.
134 A.), the free margins of which are bound to the inner surface
-of the tube by chordae tendineae. The distal extremity has a semi-
lunar valve in the left compartment (Fig. 134), which is attached
by a delicate band to the spiral valve (Ecker).

C. The minute structure of the Heart.

[The heart consists chiefly of muscle, but possesses also nerve-
fibres, nerve-cells, endothelium, and connective-tissue ; the truncus
arteriosus has in addition, blood-vessels.

a. The muscular structure of the heart.

(1) The arrangement of the muscle-fibres varies in the different
portions of the heart. That of the ventricle will be easily understood

THE- HEART. 217

by reference to Fig. 137. A layer of circular fibres (CI) extends
round the whole ventricle, and from it more or less radial or trans-

Fig. 137.

I. Transverse section through the junction of the hinder and middle thirds of the ventricle of R. tem-
ia. II. Transverse section through junction of middle and anterior thirds of the same heart.
Occ, I, Syst. 1, Leitz. The heart was freely distended! with dilnte spirit, and so hardened.—G. H.

CC - Central cavity.

CM Circular muscle.

LM Longitudinal muscle.

T™™ a Transverse muscle.
verse bands (7'/, also Fig. 138 7'M/) pass inwards ; these, in the apical
portion of the ventricle, seem to extend almost transversely across ;
towards the base they are directed onwards and forwards towards
the auricles. Of these bands some, near the apex, can be traced
directly to the opposite side, others join the wall more anteriorly,
and still others join bands of muscular fibres (LM), which may be
deséribed as longitudinal, and form the Museuli papillares. Yn the
anterior portion of the ventricle the same arrangement holds good,
but is modified to form a central cavity; still more anteriorly,
at the junction of auricles and ventricle, the trabecular structure is
much less apparent, the fibres being closer and mainly circular.

In the auricles the muscular fibres are chiefly arranged in circular
rings which cross one another; on the inner surface, however,
traces of an arrangement similar to that in the ventricle may be
made out. In the heart, from which the sections in Fig. 137

1 The base of the ventricle measured, when distended, 8 mm. by 5 mm.

218 THE VASCULAR SYSTEM.

were drawn, transverse bands (cut longitudinally), 0°33 mm. in
length, were numerous ; their central ends terminated in bands, the
fibres of which were cut transversely. The auricular septum (Fig.
141 a J)also possesses muscular fibres which cross one another in its
substance.

The fibres of the truncus arteriosus resemble those of an ordi-
nary artery; those of the sinus venosus are arranged in rings,
mostly transverse, but others oblique, and a few longitudinal. |

(2) The structure of the cardiac muscle-fibres (Figs. 138 and

41a).
|The cardiac muscle of the frog consists of spindle-shaped cells,

which as Pohl-Pincus pointed out, are of two kinds ; the main differ-

ence between the two being in the size of the nucleus, which is
much broader in one than in the other.

Fig. 138.

Portion of a transverse section through the middle of the ventricle of R. temporaria, From
same heart as the sections in Fig, 136. Oc. I, Syst. 7, Leitz.—G. H.
A Rod-shaped nuelei of muscle fibre.
B Oval nuclei of muscle fibre,
CM Circular layer of muscle.
CY Connective-tissue,
E Endothelium of the epicardium.
TM ‘Transverse bands of muscle.

a. Cells with a broad nucleus (Fig. 138 B): the nucleus is lenti-
cular or egg-shaped, 4 to 7 » broad, 8 to 14 or 18 p» long; the

ratio of length to breadth being 1 : 2. ;
g. Cells with a narrow nucleus (Fig. 138 4): the nucleus is

x a aS
ee ee ee

Ot os

— a te eit

THE HEART. 219

rod-shaped, 2°5 to 3°5 u broad and 25 to 43 mw in length. The
ratio of length to breadth varying from 1:8 to 1:16. These
cells are more frequent in the right half of the base of the ven-
tricle than the former variety. In the trabeculae the second
variety is more numerous (Pohl-Pincus).

The muscle-fibre may be simple (Fig. 141 J/) or possess branches
(Fig. 138); the fibres are all more or less spindle-shaped, and
striated transversely and longitudinally, but possess no sarcolemma.
The protoplasmic contents of the cell are finely granular; the
nucleus much more coarsely granular and possessing one or more
distinctly. marked nucleoli. The striations are due to the presence
of a network, which has been carefully described by Messrs. B. Mel-
land and C. F. Marshall', and is similar to that of ordinary
voluntary muscle (see histology of muscle). ]

b. The nerves of the heart.

The nervous supply of the heart is derived from the sympathetic
system and from the cardiac branches of the pheumogastric nerve ;
the course of which has already
been traced (page 175) to the roots Fig. 139.
of the anterior caval veins, where ~
they form a simple plexus by means
of a connecting link (Fig. 139).
The plexus possesses nerve-cells and
sends off two nerves into the auri-
cular septum ; the one (d) lies dor-
sally and is shorter and thicker than
the other (v), which lies ventrally
in the septum. They course back-
wards to the posterior border of
the septum, and there distribute
fine branches to the base of the
ventricle and surrounding parts.

[In the whole of their course in
the heart they have numerous
nerve-cells, either imbedded ‘be- Course of the cardiac nerves in the auricular

tween their fibres or attached to a Beene
the nerves and their branches. ~ v ss aa

The nerve-fibres are both me-
dullated and non-medullated. The nerve-cells (Figs. 139, 140, 141)

* I have had opportunity of examining Mr. Marshall’s slides and have convinced
myself of the correctness of his observations.

220 THE VASCULAR SYSTEM.

are usually oval, and are unipolar or rarely bipolar ; sometimes two
cells exist in the same envelope, forming the ‘twin-cells’ of
Fig. 140. Dogiel (Fig. 141b II). Acecord-
ing to the recent observations
of Lavdowsky and Dogiel each
cell receives one medullated fibre
and gives off a fine non-medul-
lated fibre ; the two run together
for a short distance, after which
the non-medullated fibre sepa-
rates to supply muscle-fibres.

Two large clusters of nerve-
cells have received special names.

Remak’s ganglion is a large
group of nerve-cells in the wall
of the sinus venosus.

Bidder’s ganglion is formed,
collectively, by groups of cells in
Group of nerve-cells on the cardiac nerve, from the suriclo-ventrivular ee?

the auricular septum, Stained with picrocar- the chief groups being attached

mine. Occ. III, Syst. 3, Hartnack ; after Dogiel. “
Hee to the two cardiac nerves.

G> Resvecsie. . No nerve-cells have been dis-
covered behind that portion of the ventricle near the auriculo-
ventricular groove, nor has a direct connection between the cells
or their processes with the fibres of the pneumogastric nerve been
made out.

Nerve-fibres have been described as existing in all parts of the
ventricle and being connected with the muscle-fibres (Openchowsky
and others); this cannot, as yet, be accepted as proved.

The truncus arteriosus also possesses nerve-fibres and nerve-cells
(Paghani, Léwit, and others), but their arrangement seems to be
very irregular. Lowit did not succeed in finding the nerve-cells in
all cases examined ; and Engelmann denies their occurrence. | °

e and d. [The endothelium and connective-tissue of the heart.

The connective-tissue of the heart exists only in very small
quantity. A fine layer on the outer surface of the ventricle,
especially towards the auriculo-ventricular groove, can easily be
seen (Fig. 138 C7’); the various valves, the auricular septum, and
more particularly the truncus arteriosus, all contain connective-

ee ee

THE HEART. 221

tissue. In the latter part the spiral valve is wholly formed of

Fig. 141 a.

Small group of nerve-cells from the auricular septum. Stained with picrocarmine and silver
nitrate, after Dogiel.

E Endothelium (endocardium).
G = Nerve-cells.

M Muscle-fibres.

NW Nucleus.

NW’ = Nucleolus.

The whole of the inner surface is lined with endothelium

Fig. 141 b.

Isolated nerve-cells from frog’s heart. I. Usual form of herve-cell. IL ‘Twin-cell.’

C Capsule.
N Nucleus.
NV’ Nucleolus.
P Process.

222 THE VASCULAR SYSTEM.

(endocardium), which covers the various

trabeculae ; the external surface-of the
. heart is likewise covered with an epi-
cardial layer of endothelium (Fig. 138
fi).

e. The blood-supply to the heart.

With the exception of the ¢runcus
arteriosus, no part of the heart possesses
blood-vessels (Hyrtl). [The ¢runcus
arteriosus (Fig. 142 6) has a rich anas-
tomosis, which receives its blood by
the arteria bulli (a), a branch of the

Fig. 142.

anastomosis with the systemic veins,
and with the hepatic portal veins : the
Arteries and veins of the Truncus former, vena bulbi anterior (v), passes

arteriosus of Bufo vulgaris, after over the auricles to open into the left

Hyrtl. F ° ‘ :
ra imnominate vein (v2); the latter, the
b Truncus arteriosus. vena bulli posterror (vc) or vena car-
h, i Hepatic portal veins. ‘ Rad:
Right and left synangium. diaca, as 1t is more usually named, passes

t

vw Vena bulbi anterior, ; . 5

oi« Tahawbomtaiaba seth. from the ¢runcus arteriosus in a fold
vc

Vena bulbi posterior (V. cardiaca). of pericardium, and then courses back-
A Right auricle. ‘ oe
A’ Left auricle, wards to open into the anterior-abdo-

V Ventricle. - minal vein. |

Il. THE ARTERIES.

(The original arrangement of this section has been modified.)

The Zruncus arteriosus divides to form two vessels (Figs. 132,
134); each of these is divided by two partitions into three com-
partments, which after a short course together separate to form
three distinct vessels, the carotid, systemic, and pulmo-cutaneous
arches. .

1. The carotid arch (Canalis carotico-lingualis, Briicke ; Ductus
_ earoticus), (Fig. 143 J) is the most anterior of the three arches : it
winds round the side of the oesophagus as far as the carotid gland,
where it divides to form two branches ; the right carotid arch gives
off a small branch to the Truncus arteriosus, the Arteria bulbi (see
above).

earotid arch. Two veins connect this

THE ARTERIES. 223

The carotid gland (Fig. 144 e’)is adilated portion of the vessel.
The interior contains bands or trabeculae of muscle, which give its

Fig. 143.

a
i \

Schema of the arterial system of Rana esculenta.

<

ce Cutaneous'artery. vy artery./
> Carotidastery. @ Subelayian artery. v

= i J-——
«) jes. Urinogenital arteries ‘

ie . External iliae artery. @ Vertebral arterx, 5

ti Internal iliac artery. _ af

y Mesenteric artery. _ TT Se a 7

x omaha 5 wife Pulmo-gutaneus arch.

224 THE VASCULAR SYSTEM.

walls a more or less spongy structure; the muscle-fibres are not
transversely striated (Hoffmann).

a. The lingual artery (Arieria lingualis, Arteria hyoidea-lingualis,
Arteria hyoidea), (Figs. 143 7, 144 L) arises by two roots from the
inner surface of the carotid gland, and courses forwards and in-
wards, supplying branches to the thyroid gland and the Museuli
geniohyoide:, to the ventral surface of the hyoid ; another continues
forwards on the outer border of the W/. Ayoglossus to supply branches
to the hyoid and tongue.

b. The carotid artery (Arteria carotis communis), (Figs. 143 ca,
144 ¢”) arises by several roots from the outer wall of the carotid
gland ; and passes over the Musculus petrohyoideus I to the anterior
end of the oesophagus, round which it courses towards the vertebral
column, and then runs forwards to the base of the skull. The artery
then courses forwards, lying immediately above the mucous mem-
brane and underneath the transverse arm of the parasphenoid, which
it crosses about midway between its back and external end ; [at this
point the artery gives off two palatine arteries, then ascends in the
orbit to the origin of the MW. pterygoideus, and divides into two

Fig. 144. branches, the internal carotid artery and the
ophthalmic artery]. The branches are :—

(1) The pharyngeal artery (Arteria pha-
ryngea ascendens), (Fig. 145 p) which runs
towards the opening of the Eustachian
tube, distributes branches to the pharynx,
and anastomoses with the Arteria pharyn-

Right carotid gland, <

: geo-maxillaris of the cutaneous artery, and
e Carotid arch. ‘ : ( ;
e’ Carotid gland. with the Ramus inframaxillaris of the
e” Carotid artery. * > deh
L Lingual artery. occipital artery.

ow) immediately divides into a number of small twigs é

At [The posterior palatine artery (Arteria palatina posterior,

ply the mucous membrane of the hinder and outer parts.of th» ..

gums. |

(3) The anterior palatine artery (Arteria palatina anterior, Vir-
chow; Arteria palatina, Ecker), (Fig. 145 p’) runs forwards, between.
the Muse. levator bulli and the mucous membrane, with the Ramus
palatinus of the trigeminal nerve. [On reaching the palatine
bone, it curves outwards to the outer anterior angle of the orbit,
where it gives off a branch backwards along the upper jaw to

the hinder portion of the orbit.] In its course it supplies twigs _

Png

THE ARTERIES. 225

to the surrounding tissues, but chiefly to the mucous membrane
and Harder’s gland.

Arterial system of Rana esculentu.

_ A Dorsal aorta. m Mesenteric artery.

* “Ad Right systemic arch. M Stomach.
As Left systemic arch. M’ Spleen.
¢ (opposite fore-limb)* Carotid artery. o Ophthalmic artery.
¢ (in abdomen) Coeliac artery. p _ Pharyngeal artery.
em Cutaneous artery. p’ Anterior palatine artery.
e Lingual artery, S Subelavian artery.
H Heart. I Carotid arch.
H’ Harderian gland. Il Systemic arch.
Ls Liver. IIT Pulmo-cutaneous arch.

Iu Lung.

(4) The internal carotid artery (Art. cerebralis, Virchow) ; see
Arteries of Brain, p. 162.

(5) The ophthalmic artery (Art. ophthalmica), (Fig. 145 0) [is
larger than the internal carotid artery at this poimt ; it crosses the
origins of the MW. rectus externus and of the WM. retrahens bulbi and
reaches the optic nerve; the artery then runs forwards along
the under surface of this nerve and of the eyeball, lying close to
the sclerotie coat as far as a little beyond the equator, where it
pierces the sclerotic coat so obliquely that the choroid coat is only

Q

926 THE VASCULAR SYSTEM.

reached at the ciliary processes. In its course the artery sup-
plies :—

a. Muscular branches, given off at the point where the artery
reaches the eyeball.

8. Two arteries (4A. ciliares) to the choroid, given off at the
same point as the foregoing.

y. Two arteries to the iris.

8. The drt. hyaloidea, the terminal portion of the ophthalmic
artery. (For further description of these vessels, see Eye.)].

2. The systemic arch (Ductus aorticus), (Figs. 132, 143, and
145 //) is the middle arch of the three; it arises from the middle
canal of the Ductus arteriosus, and winds obliquely round the
oesdphagus between the WM. petrohyoidei I-and IJ towards the
vertebral column, which it reaches at about the level of the
sixth vertebra. The right systemic arch is continued as the
dorsal aorta, the left arch communicates with it merely by a
small opening, and is then continued as the coeliaco-mesenteric
artery.

Branches of the systemic arch :—

a. The laryngeal artery (Arteria laryngea), (Fig. 146 /g) arises
from the inner border of the systemic arch before it reaches the
oesophagus ; it passes forwards and inwards to be distributed in
the larynx and pharynx. According to Briicke this artery possesses
a valve at its point of origin.

b. The oesophageal arteries (Arferiae
oesophageae) pass from the upper part of the
arch to the dorsal surface of the oesophagus.

e. The occipito-vertebral artery (Hicker),
(Art. occipito-vertebralis), (Fig. 147 0,v) [arises
from the systemic arch immediately in
front of the transverse process of the second
vertebra, and ascends immediately in contact
Transverse section at level of With the body of the first vertebra, which it

Hip Deyue separates from the MM. intertransversarii
C Carotid gland. capitis and the sympathetic cord]. Immedi-
G Glottis. ; .
Ig Laryngeal artery, ately under the most anterior portion of the
S Subclavian artery. oa wwe a :
7” Caroll Gale M. longissimus dorsi the artery divides into
IT Aortic arch. two branches, the vertebral and occipital

arteries :—

(1) The vertebral artery (Arteria vertebralis or supra-vertebralis

a Te

THE ARTERIES. 227

(Fig. 147 v) courses backwards lying on the transverse processes of
the vertebrae and on the WW. intertransversarii, under cover of the
M. longissimus dorsi. Tn this course it is close to the oblique pro-

Fig. 147.

ality

alan

T\

aie

ry

Tt \
A Vn |

Vi igi?

Le

M fA = ‘

Dissection to show the occipito-vertebral and the cutaneous arteries.

The skin of the back has been divided by a median incision and drawn to either side ; the right arm
dislocated and removed through the opening in the skin (at A). On the left side the extensor
museles of the back have been removed.

e.m, Cutaneous artery.

¢.p. Arteria cutanea pectoris.
o Occipital artery.

* Scapular artery.

v Vertebral artery.

cesses, and may even be partially covered by these; it extends
beyond the sacrum, and gives off :—
a. The Rami spinales, which pass through the intervertebral
foramina to the spial cord (see Arteries of Spinal Cord, p. 162).
8. The Rami dorsales ; these supply the muscles of the back and
send branches to the skin, which accompany the cutaneous branches

of the spinal nerves through the Saceus /ymphaticus cranio-dorsalis.

Q 2

228 THE VASCULAR SYSTEM.

y. The Rami intercostales are distributed in part to the 1M. in-
tertransversaru ; other twigs pass ventrally to the periganglionie
glands; the longest branches accompany the anterior divisions of
the spinal nerves to the muscles and skin of the belly (Fig. 145).

(2) The occipital artery (Arteria occipitalis), (Figs. 147 and 148 0),
the anterior branch of the occipito-vertebral artery, pierces the
M. longissimus dorsi; then courses forwards under cover of the
Fascia dorsalis and upon the WM. temporalis, and divides, behind the
eyeball [at the anterior border of the I. temporalis, Virchow],
into two branches :—

a. The Ramus orbito-nasalis (Fig. 148 oz) accompanies the oph-
thalmic nerve along the wall of the cranium, and passes through
the sphenethmoid, with the nasal branch of the ophthalmic nerve, to
the nose, where it divides into two branches supplying the mucous

membrane of the nose. In its course through the orbit the artery .

supplies branches to the Harderian gland and neighbouring parts,

and anastomoses with the ascending branch of the Arteria palatina.

B. The Ramus maxillaris communis (Art. temporalis, Virchow),

(Fig. 148 m) runs downwards and outwards along the anterior

border of the MW. temporalis, and passes under the anterior arm of

the squamosal bone to course backwards on the upper jaw. At

this pomt the Ramus mawillaris

Fig. 148. superior (m’) is given-off. The

yo lene main artery continues its backward

eae ney. course to the tympanic membrane,

where it divides into its three termi-
nal branches :—

[(1) The Ramus mazillaris supe-
rior (AA, maxillares superiores, Vir-
chow), usually not a single artery
but a number of small twigs, which

supply the space between the eye

Branches of the occipito-vertebral and cuta- gnd the upper jaw.
neous arteries in the head ; side view. The
skin (/7) has been reflected downwards.

(2) A small ascending branch to

SL phas woakoeeh the tympanic membrane (Virchow).
la. . levator scapulae.

0 oe naan (3) A Ramus auricularis(Virchow),
m le maxillar 5 superior. = 2 :

im’ Art, maxillaris inferior. which forms a rich anastomosis on
0 Occipital artery.. ; -
al Aik collie cbacaia the hinder wall of the tympanic

p.m. Art. pharyngo-maxillaris.

av] ig he
y. -Vertebral aiaeey cavity, and supplies a twig to t

tympanic membrane. This passes

ey

—_

THE ARTERIES. 229

from the upper border of the membrane to the point of attachment
of the Columel/a auris (extrastapedial), round which it forms a
circular anastomosis. The Ramus auricularis also anastomoses with

the cutaneous artery.

Dissection to show the occipito-vertebral and the cutaneous arteries.
The skin of the back has been divided by a median incision and drawn to either side ; the right arm
. dislocated and removed through the opening in the skin (at 4). On the left side the extensor
“muscles of the back have been removed.

¢.m, Cutaneous artery.
¢.p. Arteria cutanea pectoris.
o Occipital artery.

s

Scapular artery.
v Sp pac artery.

(4) A branch passing inwards to the fat-body, and lying immedi-
ately in front of the deltoid muscle (Virchow).

(5) A small branch running on to the inner surface of the angle
of the jaw and then forwards (Virchow).

_ A = o's
iy ee Ses

230 THE VASCULAR SYSTEM.

(6) A larger vessel, the Ramus mawillaris inferior (Fig. 148 m’’),
which arises from the Ramus maxillaris superior under cover of the
tympanic membrane, and accompanies the Ramus mandihularis of
the trigeminal nerve through the IM. masseter, or between this
muscle and the J/. temporalis to the mandible, and then courses
forwards to the chin. A large cutaneous branch is given off half-
way along the floor of the mouth. The artery gives off many
small twigs to supply the neighbouring structures. ]

3. The pulmo-cutaneous arch (Ductus pulmo-cutaneus), Figs.
132, 143, and 145 J//) is the hindmost (fifth embryonic) of the
three persistent arches; it passes upwards and forwards on the
oesophagus, and at the level of the carotid gland divides into two
branches, the pulmonary artery and the cutaneous artery.

a. The pulmonary artery (Arteria pulmonalis) runs backwards to
the root of the lung, along the outer surface of which it is continued —
in a sinuous course. It supplies the lung.

b. The cutaneous artery (Arteria cutanea magna), (Fig. 149 c.m.)
[ passes along the deeper surface of the IZ. petrohyoideus ITT until near
the prootic bone; in this course it travels forwards, outwards, and
upwards, crosses the outer border of the muscles, and appears between
the WM. levator anguli scapulae and the M. sternocleidomastoideus. At
this point the artery curves sharply round to reach the angle of the
jaw, the hinder border of the MW. depressor maxillae inferioris. The
curve so formed and the descending limb are covered by the J.
depressor maxillae inferioris. The artery then passes backwards to
form a rich anastomosis in the skin almost as far as the posterior ~

end of the trunk. It supplies the following branches :—

_ (1) The Ramus dorsalis (Virchow) arises immediately in front of
the curve of the main artery; it ascends behind the I. temporadis,
and passes along the anterior border of the WW. depressor maxillae to
the skin, where it curves backwards, It supplies small twigs
forwards as far as the eyelids.

(2) The Ramus auricularis (Virchow) also arises in front of the
curve in the cutaneous artery; sometimes it arises from the Ramus
dorsalis. 'The artery winds around the J. petrohyoideus ITT near its
insertion, and so reaches the posterior wall of the tympanic cavity,
where it anastomoses with the 2. auricularis of the Ramus mawillaris
communis.)

(3) The Arteria pharyngo-maxillaris (Fig. 148 p.m.) is a small
branch running forwards and outwards to supply the mucous mem-
brane of the larynx, Eustachian tubes, gums, the lower jaw, and

THE ARTERIES. 231

the skin under the mouth. It forms a rich anastomosis with
branches of the Ramus mazillaris inferior of the occipital artery,
and with others from the pharyngeal branch of the carotid artery; -
a large branch passes forwards to supply the skin of the throat
and floor of the mouth.

(4) The Arteria cutanea pectoris (Fig. 149 ¢.p.) is distributed to the
skin of the breast.

4. The subclavian artery (Arteria suiclavia), (Fig. 150 8).
The subclavian artery arises from the systemic arch immediately
behind the occipito-vertebral artery at the level of the second or
third vertebra. The artery then runs outwards alongside and in
front of the brachial nerve, between the MW. subscapularis and the
M. triceps to the arm, where it is known as the brachial artery; in
its course it gives off :—

a. The Arteria costo-cervicalis (Fig. 150, 1). This artery arises
near the systemic arch, and runs backwards, parallel to the ver-
tebral column, over the brachial nerve, and across the transverse
processes of the vertebrae. It is distributed more especially to the
M. obliquus internus.

b. The Arteria
corace - clavicula-
ris (Fig. 150, 2)
arises more ex-
ternally than the
last artery; it
accompanies the
coraco -clavicular
nerve on the dor-
sal surface of the
ventral portion
of the shoulder-

Fig. 150.

girdle, and passes
between the W.
deltoideus and M.,
subscapularis into
the Foramen ovale, 4 Systemie arch. s Subelavian artery.
J =o ’ Dorsal aorta. U_ Utmar artery.
where it divides e Arteria cutanea medialis superior. 1 Arteria costo-cervicalis.
to supply these ¢ Arteria cutanea medialis inferior. 2 Arteria coraco-clavicularis.
; ls M. levator scapulae. 3. +Arteria scapularis posterior.
muscles and the ov pea meor artery. 4 Arteria ecapularis superior.
. Pp rteria pectoralis, Cutaneous artery.
M. pectoralis. R_ Radial artery. é Arteria cabbeeearia.

232 THE VASCULAR SYSTEM,

e. The Art. scapularis posterior (Fig. 150, 3), a small branch
arising’ opposite at the tip of the second transverse process and
passing backwards over the WM. transverso-scapulares, to which it is
distributed.

d. The drt. scapularis superior (Fig. 150, 4) accompanies several
nerves between the MW. subscapularis, M. transverso-scapularis major,

Fig. 151. Fig. 152.

Arteries of the palmar surface of the hand. Arteries of the dorsal surface of the hand,
B Ulnar artery. B Ulnar artery.
ci RB, cutaneus medialis inferior, cri RR. cutan. rad. inferior.
dad ___ Digital branches. hk Radial artery
FM. flexor digitorum communis. Zl Thumb.
II Thumb. V Fifth finger.

V Fifth finger.
and the long head of the M. triceps towards the dorsal surface,
where it is distributed to the WM. infraspinatus, latissimus dorsi, ete.
e. The Ramus cutaneus maxillaris. : 2
f. The Art. subscapularis (Fig. 150, 6) is distributed in the sub-
scapular muscle.

A. The brachial artery (Arteria brachialis), (Fig. 150) accom-
panies the brachial nerve under cover of the long head of the
M. triceps and over its inner head to the Plica cubiti, into which it
sinks near the tendon of the WM. sternoradialis ; beyond this point it
is continued as the ulnar artery. Jn its course the brachial artery
gives off :—

a. The Arteria pectoralis (Fig. j15° p)-

b. The Arteria cutanea medialis superior (Fig. 150 ¢).

ce. The radial artery (Arteria radialis), (Fig. 150 R) which winds

THE ARTERIES. 233

round the humerus with the radial nerve between the muscles of the
outer side of the forearm, to which it gives branches: in the palm
of the hand it passes between the W/. extensor carpi udnaris and the
M. flexor antibrachii to the dorsal surface of the hand, where it
anastomoses with the ulnar artery. In its course it supplies :— —

(1) Muscular branches to the surrounding muscles.

(2) The Ram. cut. radialis inferior, which arises from the radial
artery towards the distal end of the forearm, and passes underneath
the MW. flexor carpi ulnaris to the skin.

B. The ulnar artery (Arteria ulnaris), (Figs. 150 U, 151 B) ac-
companies the ulnar nerve towards the hand, passes between the
M. flexor digitorum communis and the M. anconeus to the palm of the
hand, and then winds round the outer side to the dorsal surface
of the carpus to form its terminal branches. The branches are :—

(1) The titan. med. inferior (Fig. 151 ci); it arises near
the wrist-jomat and supplies (a) twigs to the skin of the inner sur-

face ; (8) a branch downwards, which courses along the inner side
of the second finger to its tip; and (y) a branch which passes
upwards to anastomose with the R. cutaneus medialis superior.

(2) In the palm of the hand a branch (Fig. 151 @) is given off,
which divides to form Arteriae digitales volares: one for the second
finger, two for the third finger, two for the fourth finger, and one
for the fifth finger.

(3) Given off on the dorsum of the hand (Fig. 152) it supplies
branches corresponding exactly with those of the palmar surface.

_ 5. The dorsal aorta (Aorta communis s. aldominalis (Fig. 153 A).

The two systemic arches unite at about the level of the sixth vertebra
to form the dorsal aorta: as already mentioned the union is very
incomplete, the dorsal aorta being practically a continuation of the
right systemic arch, and only communicating with the left by
means of a small opening. The branches are as follows :—

a. The coeliaco-mesenteric artery (Arteria intestinalis communis),
(Fig. 153), the true continuation of the left systemic arch, at once
divides to form the gastric and mesenteric arteries.

(1) The gastric artery (Arteria gastrica s. coeliaca) (c) immediately
divides into two branches :—

a. The Ramus dexter s. anterior ; this artery gives off the Arteria
hepatica to the liver and gall-bladder and passes to the right (an-
terior) surface of the stomach, running along the attachment of the

234 THE VASCULAR SYSTEM.
mesentery and supplying branches forwards to the oesophagus and
backwards towards the intestine.

B. The Ramus sinister s. posterior passes to the left (posterior)
surface and behaves like the Ram. dexter.

(2) The mesenteric artery (Arteria mesenterica superior and infe-
rior, and the Arteria splenica), (Fig. 153 m) supplies :—
. The superior mesenteric artery, which supplies the upper part Of <

Fig. 153.

a

Arterial system of Rana esculenta.
Mesenteric artery. o

A Dorsal aorta. m

Ad Right systemic arch. M ~ Stomach.

As Left systemic arch. M’ Spleen.

€ opposite fore-limb) Carotid artery. o Ophthalmic artery.

¢ (in abdomen) Coeliac artery— p Pharyngeal artery.

em Cutaneous artery. © p’ Anterior palatine artery.
€ Lingual artery. S Subclavian artery.

HH Heart. I Carotid arch.

H’ Harderian gland. ° II Systemic ach.”

L Liver. III Pulmo-cutaneous arch.
Lu Lung.

the intestine, and gives off a recurrent branch to the stomach, which
anastomoses with the gastric arteries.

B. The splenic artery to the spleen.

errener eras rpm mere raya res * taal

THE ARTERIES. 235

y. The inferior mesenteric artery to the lower part of the intestine.

All the arteries to the intestine course in lymph-spaces.

b. The urinogenital arteries (Arteriae urino-genitales), (Fig.
154 ug) are four to six small arteries arismg from the ventral
surface of the aorta between the kidneys : they immediately divide
into right and left branches to supply the kidneys, fat-bodies,

_ reproductive organs, and their ducts (see kidney).

ce. The lumbar arteries ( Arteriae /umbales), are small paired vessels
to the neighbouring muscles, and send branches through the in-
tervertebral foramina to the vertebral canal. Sometimes these
arteries arise from the Art. spinalis or Art. vertebralis, ete.; in the
former case they pass outwards from the vertebral canal to the sur-
rounding structures.

d. The haemorrhoidal artery (Art. mesenterica inf. s Art. hae-
morrhoidalis superior) is a small median artery running from the pos-

terior end of the aorta to the large intestine.

6. Bifurcation of the aorta. The
iliac arteries (Arferiae iliacae commu-
nes). Opposite the middle of the uro-
style the aorta bifurcatés to form the ,
iliae arteries; each of these courses
on the corresponding sciatic plexus to
the thigh, beyond which it is con-
tinued as the sciatic artery. The
branchés of the iliac artery are :—

_a. The vesico-epigastric artery
(Arteria epigastrico-vesicalis), (Fig. 155
ev); it arises near the bifurcation,
passes outwards on the plexus, and
divides into two branches :—

(1) The epigastric artery (Arteria

Fig. 154-

The urinogenital arteries.
A Dorsal aorta.

epigastrica) (e) immediately gives off H Testis.
a recurrent branch to the iliac bone “ —se ME aiteaioa.

and the MW. ilio-coceygeus; it then
continues to the ventral muscles of the abdominal wall, where it
runs forwards on the deeper surface of the VW. obliquus internus, and
is distributed more especially to this muscle.

(2) The hypogastric artery (Arteria vesicalis) (v) winds downwards
around the sciatic plexus to reach the mesentery, along which it
courses to the bladder, where it forms a rich anastomosis.

236 THE VASCULAR SYSTEM.

b. The femoral artery (Arteria femoralis s. crurglis), (Fig. 155 f)
is the representative of the femoral artery of man, although it does
not perform the same functions. The artery passes under the
hinder free border of the MW. obliquus internus to the thigh, where it —
lies upon the I. /io-psoas, and sends twigs to the neighbouring
muscles, the skin, and lymph-sac (Lamina inguinalis), and then
divides into :—

(1) A twig, which runs forwards on the ventral surface of the
iliac bone and is covered by the epigastric artery.

(2) A twig, running forwards and downwards on the MM. ilio-
psoas, vastus internus, and sartorius, to send branches to the hip-joint.

ce. The spermatic artery (Arteria spermatica), which arises, in
males, from the iliac artery, and.ascends to the Vesicula seminalis.

7. Arteries of the hinder
extremity.

Fig. 155.

A. The sciatic artery (Ar/e-
ria ischiadica), (Fig. 156 2) is the
continuation of the iliac artery ;
it leaves the pelvis between the
hinder (outer) border of the J/.
coccygeo-iliacus and the inner
surface of the origin of the ©.
ilio-psoas, then lies between the
former muscle and the origin of
the WM. vastus externus. It ap-
pears on the thigh between the.
vastus externus (in front) and the
M. pyriformis (behind); it is the
main arterial trunk for the hinder ©
Bifurcation of the aorta and the iliac arteries. extremity. The artery courses

6: Bplemae arse: backwards, lying upon the sciatic

ev Vesico-epigastvic artery.

f Femoral artery. nerve and between the M. biceps
o Internal oblique muscle, . .
o> “Neaionl axGean: and the MW. semimembranosus ; in

this course it runs in a lymph-
space placed in the Septum femorale superius (see page 259).
Arrived at the popliteal space the artery bifureates to form the
peroneal and tibial arteries; near the pelvis it gives off two
branches (a) and (b), and in its course along the thigh two
branches (¢) and (d).

a. The Art. haemorrhoidalis inferior (i) runs backwards and

THE ARTERIES. 237

inwarda under the MW. pyriformis to be distributed in the W/. sphincter
ani and the skin of the anus.

b. The Art. cutanea femoris posterior v. superior (cf) rans with the
corresponding nerve and the J. pyriformis, and over the IW. semi-
membranosus to the skin of the inner and hinder surfaces of the
thigh.

e. The Rami musculares supply the M. semimembranosus, the M.
biceps, and the MM. extensores auris; the branch to the WM. rectus
inferior major pierces the muscle in company with the nerve, and
is continued as :—

d. The Art. eutanea femoris media (cf’) to the skin of the middle
of the inner surface of the thigh. Several small twigs pierce the
M. rectus internus minor,
reach the skin, and Fig 156.
communicate with this
artery.

Arteries of the hinder extremity.
Art. cutanea caleanei.
Cutaneous branch of the fe-
moral artery.

Art. cutanea fem. post. supe-
rior.

Art. cutanea femoris media.

Art cut. genu lateralis supe-
rior.

Art. cireumfiexa genn lateralis
inferior.

Art. circumflexa genu superior
medialis,

Art. circumfiexa genu inferior

py Pee ia
M. pyramidalis, 2 J _,

ETE"REATY NVPATMRSA gg € ag 4 A
—

B. The peroneal artery (vf. peronea), (Fig. 156 p) runs out-

238 THE VASCULAR SYSTEM.

wards under cover of the tendon of the I. biceps femoris, and
accompanies the peroneal nerve downwards to give off :—

a. The Art. circumflexa genu lateralis superior, which runs forwards
on the outer side of the knee, gives a twig to the joint, and is
continued as :—

b. The Art. cutanea genu lateralis superior (eg/) to the ‘skin of the
anterior and outer sides of the knee. It anastomoses with branches
of the Arteriae circumflexae genu mediales to form a rich anastomosis
(Rete articulare genu): other branches pass upwards to inosculate
with the Art. cutanea femoris anterior (cf), and others downwards
to anastomose with the next artery.

e. The Art. eircumfleaa genu lateralis inferior (cgl’) rans under
the tendon of origin of the gastrocnemius to the outer side of the
knee, and terminates in the skin as the Art. cutanea genu lateralis
inferior. Some of the cutaneous twigs pass upwards to anastomose
with the Art. cut. genu lat. superior, others downwards to anastomose
with the Ad. madleolares.

d. A muscular branch (p’) for the IW. peroneus ; it is the real
continuation of the peroneal artery, and runs behind the outer
tendon of origin of the gastrocnemius to be distributed in the
M. peroneus.

C. The tibial artery (Arteria tibialis), (Fig. 156 ¢), arises at
the bifurcation of the sciatic, and runs inwards, meeting the
tibial nerve between the tendons of origin of the 1. gastrocnemius,
and deep in the popliteal space under cover of the calf-muscles. It
then pierces the MW. tzbialis posticus, and leaves this to perforate the
tibio-fibula (see p. 50), appearing again on the anterior surface
as the anterior tibial artery. Before meeting the tibial nerve this
artery gives off the following branches :—

a. The Art. circumflexa genu superior medialis (cgm), which winds
round to the front of the knee-joint, and gives off a cutaneous
branch, the Art. cutanea genu medialis superior, which is distributed
in the skin of the inner side of the knee and anastomoses above with
the Art. cutanea femoris media, below with the following branches
(b, ec, and d).

b. The Art. circumfleaa genu inferior medialis (cym’) supplies twig's
to the knee-joint, and passes to the skin of the knee and inner
surface of the calf as the Art. cutanea inferior medialis.

e. Muscular twig's to the J/. gastrocnemius.

THE ARTERIES. 239

d. The Art. suralis (su); this accompanies the N. suralis down-
wards along the calf-muscle, and is distributed in the skin of the
inner side of the heel.

e. While passing between the fibres of the W. tzbialis posticus, the
tibial artery gives off muscular twigs ; one larger than the rest is |
known as the Ramus descendens.

D. The anterior tibial artery (Arteria tibialis antica), (Fig.
157 4.2.) is the continuation of the tibial artery after piercing the
tibio-fibula. It runs Fig. 157.
downwards on the
anterior surface of
the leg, then between

‘the two heads of the
MM. tibialis anticus to
the dorsum of the
foot, where it is con-
tinued as the Artfe-
ria dorsalis pedis. \t
supplies:— ~

a. Rami musculares
to the WM. peroneus,
M. extensor cruris,
and to the W. flexor

4.

or.

_ inferior
(c.c.i.) passes between
the two heads of the
M. tihialis anticus to
the skin of the ante-

Arteries of the dorsal surface of the foot.

rior and outer sides ec. Art, cutanea calcanei.
. ¢.c.i, Art. cutanea cruris inferior.
of the leg. Ft! M. flexor tarsi.
h Art. cutanea hallucis.
e. The Art. cuta- ix Art. interomsea dorsalis I.
n ° 3 - i2 Art. interossea dorsalis II,
= caleanet (c.c ) 18 i3 Art. interossea dorsalis IIL.
given off at the is Art. interossea dorsalis IV.
kl ate % mil Art. malleolaris lateralis.
ankle-jomt; it runs m.m, Art. malleolaris medialis.
t.a. Anterior tibial artery.
outwards on the ta* Bifurcation of the dorsalis pedis artery.
lower end of the tr Art. tarsea. -

tibio-fibula, giving branches to the joint, then backwards between

240 THE VASCULAR SYSTEM.

the tibio-fibula and the WM. peroneus to be distributed to the skin
of the heel. Above it anastomoses with the A. cireumflexa genu inf.
lateralis, and below with the malleolar arteries.

d. The Art. malleolaris lateralis (m/l) arises a little beyond the
last artery ; it runs outwards under the origin of the J/. flewor tarsi,
gives branches to the joint and muscles, and terminates in the skin
of the outer border and dorsal surface of the foot.

e. The Art. malleolaris medialis (m.m.) arises at about the
same level as the Art. madlleolaris lat. from the inner border of the
anterior tibial artery. It supplies branches to the joint, gives nu-
merous branches to the skin, which anastomose with the Art. sura/is,
and passes to the inner border of the foot, where it ends by dis-
tributing branches to the I. plantaris, the extensor aponeurosis, and,
as the Art. cutanea plantaris, to the skin of the-sole of the foot.

EK. The dorsal artery of the foot (Art. dorsalis pedis), (Fig.
157 ¢.a.) runs under the I. flexor tarsi posterior to the point ta*,
where it is superficial; the artery then
bifureates ; the branches are :—

Fig. 158.

a. The Art. tarsea (tr) which arises from
the dorsal artery of the foot while under
cover of the M. flexor tarsi. posterior ; it
passes to the MZ. extensor digiti V and to
the skin of the dorsum and outer border
of the foot. One branch courses along
the outer border of the fifth toe to its tip ;
another passes upwards to anastomose
with the neighbouring vessels.

b. The inner branch, formed by the
bifurcation of the dorsal artery of the
foot, at once divides to form :—

(1) The Art. cutanea hallucis (h) to the
supplemental great toe.

(2) The Art. interossea dorsalis I (i),

Arteries of the sole of the foot. which at once bifureates to form two

Sebi medina Rami digitales for the first and second toes;

pf Rami perforantes, s E
these inosculate with the Art. cutanea
plantaris, and send twigs to the skin of the inner border of the foot.

e. The outer branch formed by the bifureation of the dorsal
artery divides to form the Arteriae interossei dorsales II, ILI, and 1V
(77, 7°, 7); they are distributed in a rich anastomosis to the web.

THE VEINS. 241

d. The Arterig interossea (Fig. 158
artery of the foot at the tarsus, and perforates the membrane
tween the astragalus and caleaneum to

e reach the sole of the foot.
Tt forms a rich subcutaneous plexus on the

?) arises from the dorsal]

Y the veins, which conduct the blood di-
rectly or indirectly to the auricles. The pulmonary yein opens -
directly into the left e three Venae carae open into the

US Venosus. “Rance ptt

A. Vein Opening into the left auricle,
: The pulmonary vein (7

: m 4 common trunk, the pulmonary Vein, -
: which opens into the left auricle (see p. 215).

(Vena Jugularis externa), (Fig.
159 je) is formed, at the outer border of the hyoid bone, by the
union of two Veins ;—

(1) The lingual vein (Vena Lingualis) (Fig. 16yY, 2). This originates
at the tip of the tongue and Passes in a very tortuous course along
€ of the hyoid 3 It receives numerous branches
te and hyoid muscles,

R

242 nee

VASCULAR SYSTEM.

(2) The mandibular vein (Vena mazillaris inferior), (Fig. 161 m)
runs along the insertion of the MW. submazillaris, and turns inwards

at its hinder border to join the lingual vein.

b. The innominate vein (Vena anonyma), (Fig. 160 A) is formed

Fig. 159.

by the union of the
internal jugular and
the subscapular veins.
By tracing the inno-
minate vein upwards
between the suspenso-
rium and the shoulder-
girdle, the internal
jugular vein will be
seen to receive the
vertebral vein at the
outer border of the. J/.
levator scapulae. The
left innominate vein
receives the Vena bulln
anterior from the Trun-
cus arteriosus (p. 222).
Schema of the veins of Rana
esculenta.

Subclayian vein,
Anterior abdominal vein,
Right auricle.
Left lwuricle,
Anterior vena cava.
Posterior vena cava.
Cutaneous vein. :
Vena dorso-lumbalis.
Intestine.
Femoral vein.
Sciatic vein. :
Vena communicans iliaca,
Exteynal jugular vein form-
ed by lingual and maxil-
lary veins 7 and m.
i Internal jugular vein.
L
WN
0
iz! od

Hepatic veins.
Kidney.”
Oviducal veins.
> Hepatic portal vein.
val Renal portal vein.
rail Secondgry renal portal
veins.
ve Renalweins,
8 Subscapular vein,
“SG Sanus Yenosus.
va Innommate vein.

“Be Vena bulbi posterior (car-

diac véin
up Pulmonary veins,
re

oe, or

THE VEINS. 243

(1) The internal jugular vein (Vena jugularis), (Fig. 160 J) can
be traced from the border of the MW. /evator scapulae upwards and
forwards to the hinder part of the prootic bone: it then passes

forwards under the lateral process of the prootic, in a groove on

the anterior surface of the same bone, towards the hinder angle of
the orbit, where it receives the ves from the cranial cavity (see
vessels of brain, p. 165), and also a branch from the orbit.

Fig. 160.

x

Distribution of the internal jugular vein and the anterior portion of the cutaneous vein.
_

A Innominate vein. @& Yena orbitalis posterior.

™~em. Cutaneous vein. P Lateral process of the prootic bone.

—f Nasal vein, ~S | Subscapular vein.
h Harderian gland. S Shoulder-girdle.
H Skin, reflected downwards. T Tympanie membrane.

~~ J _ Internal jugular vein. —V Vertebral vein.

£ ~ Anterior lymph-heart. 2 Transverse process of the second vertebra.
t= -M. levator scapulae. 3 Transverse process of the third vertebra.
0 - M. obliquns internus, 4 Transverse process of the fourth vertebra.
o Vena orbitalis anterior.

S

. [The Vena orbitalis media (Virchow) ; it arises from the an-
terior internal angle of the orbit, from the Harderian gland, the
nasal cavity, or from other veins on the anterior wall of the orbit.
The vessel lies close to the cranium, immediate] y underneath the
Arteria nasalis, and sinks under the M. rectus superior to join the
internal jugular vein. It its course it receives the Vena bulbi supe-
rior (see eye), and near its termination communicates with the
Vena orbitalis posterior. ]

R 2

244)

n

THE VASCULAR SYSTEM.

B. The Vena vertebralis (Fig. 160 V) arises posteriorly and runs

forwards over the transverse processes of the vertebrae, the Museudi
intertransversarii, and the WM. devat. scapulae, to join the internal
jugular vein. In its course it receives branches (Venae spinales)
from the vertebral canal through the intervertebral foramina, and
cutaneous branches which accompany the corresponding arteries and

nerves through the dorsal lymphatic sac.

The vein pulsates in

consequence of its connection with the anterior lymph-heart (Miiller).

(2) The staeayetee vein (Vena subscapularis), (Fig. 160 8).

Fig. 161.

The anterior caval vein and its branches.

a Innominate vein,
cm, Cutaneous yein.
cs, Anterior cava vein.

Z Internal jugular vein.
i’ External jugular vein.

a

aC,

Lingual vein,

Mandibular vein.

Brachial vein,

Subscapular vein.

Yn

-

This vein arises in
the transverse abdo-
minal muscles and
the muscles of the
shoulder girdle; it
unites with the in-
ternal jugular vein
under the shoulder-
girdle.

ce. The subclavian
vein (Vena subclavia),

_. (Fig. 159) passes
backwards from the

anterior caval vein

on the dorsal surface

of the coracoid bone

_ and the clavicle, and

then under cover of
the Portio sternalis
of the MW. pectoralis
major, to the internal

border of the Portio

abdominalis of the
M. pectoralis major,
where it is formed
by the union of the
cutaneous vein and
the brachial vein.

(1) The cutaneous
vein (Vena cutanea

magna, Ecker; Vena

fi

NS

THE VEINS. . 245

musculo-cutanea, Graby), (Figs. 160, 161, and 162 ¢c.m.). This vein
arises by small branches in the head ; these are :—

a. The Vena nasalis (Virchow) ; it arises by an upper and a lower
branch from around the nostril, and courses backwards along the
superior maxillary bone to about the middle of the orbit, where it

joins the facial vein.

B. The Vena orbitalis anterior (Virchow), (Vena ophthalmica ante-
rior, Ecker), (Fig. 1600) commences at the Harderian gland from a
rich anastomosis,
receives branches
from the floor and
anterior wall of the
orbit, and joins the
facial vein with the
Vena nasalis.

y. The Vena orbi-
talis posterior (Vir-
chow), (Vena oph-

thalmica posterior, Course of the cutaneous vein as seen from the side.
Ecker), (Fig. I 60 0’) c.m, Cutaneous vein.

= dM, depressor maxillae,
arises on the pos- ¢ “MC ifrespinatus.

terior wall of the

orbit on the M. pterygoideus ; it passes under the Processus zygoma-
ticus to join the facial vein, and in its course receives the Vena
ophthalmica (see eye), and communicates with the Vena orbitalis
medialis and the internal jugular vein.

8. The Vena facialis (Fig. 160) is formed about the middle
of the orbit by the union of the Vena nasalis and the Vena orhitalis
anterior ; it courses backwards towards the angle of the jaw. On
reaching the MW. depressor marillae, about 4 mm. in front of the
angle of the jaw, it passes on to the skin. It receives in its
eourse the Venae palpebrales (Fig. 162) and the Vena orbitalis
posterior.

The musculo-cutaneous vein is the direct continuation of the
Vena facialis after this has left the upper jaw; it immediately
receives one or more twigs (Venae tympanicae), (Fig. 162) from the
tympanic membrane and the tympanic cavity.

The vein then courses backwards in the outer wall of the lateral
lymph-sae as far as the middle of the trunk, where it passes, by
means of the Septum abdominale, to the outer border of the Portio

246

~ THE VASCULAR SYSTEM.

abdominalis of the M. pectoralis; here the vein curves round to pass
forwards between the fibres of this muscle to its inner border where
it terminates by joining the brachial vein. In the whole of this
lengthy course the vein receives numerous branches from the
neighbouring parts.

Veins in the region of the kidney.

Fig. 163.

Renal portal vein.
Dorso-lumbar veins.
Anterior abdominal vein.
Intestine.

Femoral vein.

Oviduct.

Oviducal veins,
Mesenteric veins,
Renal veins,
Bladder.
Posterioryvena cava.
Vesical velws.

Sciatic vein.
Kidney,
Right ovary, drawn to the left.

(2) The brachial vein
(Vena brachialis) is formed
in the Plica cubiti by the
union of two veins.

a. The radial vein
(Vena radialis) arises on
the dorsum of the hand
from a venous arch, the
distal convexity of which
receives the Venae digitales
dorsales : the vein courses
superficially along the
outer side of the forearm
to the elbow.

B. The ulnar vein
(Vena ulnaris) arises from
the veins in the palm of the
hand, and courses towards
the elbow, lying deeply
between the muscles of
the inner and outer sur-
faces of the forearm. In
the elbow the vein be-
comes superficial near the
tendon of the MW. sterno-
cleidoradialis, and joins
the radial vein to form
the brachial vein.

The cutaneous veins
of the fore-limb follow
courses corresponding:
with those of the arteries.

2. The Posterior Caval
Vein (Vena cava inferior),

(Fig. 159 Cp, 163 v.c.i.).

THE VEINS. 247

The posterior caval vein is a median vein which, commencing be-
tween the kidneys, runs forwards to open into the posterior end
of the Sinus venosus. It receives the hepatic, renal, and ovarian or
spermatic veins.

a. The hepatic veins (Venae hepaticae), (Fig. 164 v.h.) are two in
number, one from either side of the liver; they open into the
posterior caval vein near the Sinus venosus.

b. The renal veins (Venae renales or Venae revehentes), (Fig.
163 r) are four or five small vessels on each side ; they pass from
the inner border of the kidney inwards and forwards, to form,
by their union, the posterior caval vein. The must anterior receive
branches from the fat-bodies (see kidney).

ce. The spermatic or ovarian veins are four or five in number on
each side ; they open into the posterior caval vein between the renal
veins.

3. The Portal Systems.

[There are, in the frog, two portal systems; the renal and the
hepatic. Each of these receives vessels which are derived, directly
or indirectly, from the veins of the hinder extremity.

The femoral vein on entering the pelvis divides to form two
branches ; an iliac vein placed dorsally, and a pelvic vein placed
ventrally ; the two pelvic veins converge to the middle line of
ventral wall of the abdomen, where they unite to form the ante-
rior abdominal vein. |

a. The renal portal vein (Vena renalis advehens princeps), (Fig.
163 a). This vein is formed by the union of the sciatic and the
iliac veins ; it courses forwards to the outer border of the kidney,
and is distributed, by numerous branches, to that organ, chiefly
on its dorsal surface. It receives the following veins :—

(1) The iliac vein (Vena tliaca externa); this is the dorsal branch
formed by the bifurcation of the femoral vein.

(2) The sciatic vein (Vena ischiadica), (Figs. 163 and 165 #)
arises at the popliteal space, courses upwards in company with the
sciatic nerve between the W. semitendinosus and the M. biceps, then
passes, still with the nerve, between the MW. vastus externus and the
M. pyramidalis into the pelvis. It continues forwards to join the
iliac vem. At the root of the thigh this vein communicates with
the femoral vein by the Ramus communicans iliacus.

248 THE VASCULAR SYSTEM.

(3) The dorso-lumbar vein (Vena dorso-lumbalis), (Fig. 163 a’) is
a vein (or more usually several) arising by twigs in the dorsal and
outer walls of the abdomen ; it joins the renal portal vein opposite
the kidney.

(4) The oviducal veins (Fig. 163 ov) are irregular veins from
the oviducts, which open either into the dorso-lumbar vein, or into
the renal portal vein.

b. The hepatic portal system.

The liver receives blood from two sources: (1) from the hind-
limbs by means of the

FRE OP 4: anterior abdominal
\ vein, and (2) from the
alimentary canal by

the hepatic portal vein.

The anterior ab-
dominal vein (Vena
abdominalis),(Figs.159
ab, 164 Va) is formed,
a little in front of the
symphysis pubis, by
the union of the two
pelvic veins. It courses
forwards . along the
middle line of the
ventral body-wall un-
til opposite the liver,
where it ascends and
divides into three
branches, of which
two enter the right
and left lobes of the
; : liver respectiveyl. The
a See left branches of Neate aay third, the Ramus de-

anterior abdominal vein. Pt Gastric veins. scen den &, j oins the
b Ramus descendens. S Sinus venosus. i cs
c Vena bulbi (Vena cardiaca). V_-Ventricle. hepatic portal vein.
D Intestine. ‘ Va Anterior abdominal F .
G Gall-bladder. Bie The anterior abdomi-
L.l, Left lobe of liver. V.c.7, Posterior vena cava. ‘ eet

a i

L.r, Right lobe of liver. v.h. Hepatic veins, nal Drie tat ths the

following veins :—
a. The vesical vein (Vena vesicalis), (Fig. 163 Vv); a median
vein arising in the groove between the lobes of the bladder from
lateral branches, which extend outwards on the bladder. This vein

THE VEINS. 249

communicates above with other vesical twigs which open into the
haemorrhoidal vein.

B. Parietal veins, which join the anterior abdominal vein in its
course along the ventral body-wall.

y. A cardiac vein (Vena cardiaca), (Figs. 142, 159 ve, 164 ¢),
which joins the anterior abdominal vein just before its division
(see p. 222).

The hepatic portal vein (Vena portarum), (Figs. 159, 164 P)
is formed by the union of the gastric, intestinal, splenic, and one
of the haemorrhoidal veins. The large vein so constituted passes
forwards towards the liver, receives the Ramus descendens from the
anterior abdominal vein, and then passes into the left lobe of the
liver. Its branches are the following :—

(1) The gastric veins. The stomach has three veins :—

a. [The Vena coronaria ventriculi, which receives blood from the
hinder end of the oesophagus and anterior portion of the stomach.

_ Band y. Two other veins which form an Arcus coronarius on the
concave surface of the stomach; the hinder receiving in addition
the small Venae pancreaticae and the Vena duodenalis; the trunk so
formed receives the Vena coronaria ventriculi (Hoffmann).

(2) The intestinal veins; the veins of that portion of the ali-
mentary canal between the middle of the duodenum and the
anterior end of the large intestine open into a common vein which
joins the hepatic portal vein.

(3) The splenic vein joins either the hepatic portal vein or one
of the intestinal veins. °

(4) The haemorrhoidal veins are three in number; the anterior

opens into the splenic vein, the remaining two into the portal veins
through the agency of the intestinal veins. |

4. The Veins of the Hinder Extremity.

The hinder extremity has two venous trunks, the sciatic vein and
the femoral vein.

a. The femoral vein (Vena femoralis), (Fig. 165 f) is the larger
venous trunk of the hinder extremity. It arises in the popliteal
space as a direct continuation of the posterior tibial vein, courses
upwards in company with the sciatic artery and nerve, then leaves
these to wind forwards and outwards, and appears between the
origins of the WM. vastus externus and of the M. rectus anterior.

250 THE VASCULAR SYSTEM.

The vein here gives off the Ramus communicans iliacus to the sciatic
vein, and turns forwards and downwards around the J/. glutaeus
maximus to reach the floor
of the pelvis, near the fe-
moral artery. The vein
then bifurcates to form the
pelvic and iliac veins.

Fig. 165.

(1) The Ramus commu-
nicans tliacus (Fig. 165 ¢.i.)
forms a communication
with the sciatic at the base
of the thigh.

(2) The posterior tibial
vein (Vena tibialis postica),
of which the femoral is a
continuation, arises on the
dorsal surface of the toes
and foot. It runs super-
ficially on the M/. extensor’
longus digiti primt over the
ankle-joint, courses up-
wards and winds round
the outer surface of the
tibio-fibula to the flexor
surface. It receives, in its
| course, muscular branches,
/ and at the knee a large
cutaneous branch.

b. The sciatic vein:
this vein has already been
described (see p. 247), but

Veins of the hinder extremity, half schematic. the vein from which t

cd: Vest eotanebainene Tiladk: arises requires description.
I: Femoral vein, 5 dg Ue

é — Sciatie vein. The anterior tibial
i Vena cutanea cruris medialis. ° rr of aoe

9a Ms tok vein (Vena tibialis an
ai a ag eth isi tica) arises on the dorsum

v.e. M, vastus externus.

of the foot by twigs from
the toes; it courses under the MW. extensor longus digiti primi, then
upwards on the anterior surface of the leg, and enters the canal in
the tibio-fibula to appear on its hinder surface. The vein then

THE LYMPHATIC SYSTEM. 251

receives twigs from the MW. peroneus, the M. tibialis posticus, the MW.
gastrocnemius, and a large cutaneous branch.

a. The Vena cutanea cruris medialis (Fig. 165 2’) receives branches
from both above and below, and enters the popliteal space to join
the anterior tibial vein.

8. The anastomosis on the dorsum of the foot, from which the
anterior tibial vein arises, receives perforating twigs from the
plantar surface.

PART IL
THE LYMPHATIC SYSTEM.

(The arrangement of this section has been considerably altered.)

[The lymphatic system of the frog may, for descriptive purposes,
be advantageously treated of in four parts :
1. The subcutaneous lymph-sacs.
2. The lymph-hearts.
.3. The lymph-spaces of the body, and those lying between
the various organs.
4. The lymph-vessels of the separate organs.

The first two parts will be described in this section ; the remainder
with the organs or parts of the body with which they are more
intimately associated. The spleen will be described with the ab-
dominal viscera.

1. The Subcutaneous Lymph-Sacs.

A number of large spaces exist between the skin and the muscles,
in which there is no direct attachment between these parts. These
spaces are separated from each other by thin connective-tissue
septa, stretched between the muscles and the skin, and by attach-
ments of the skin to the underlying structures.

Joh. Miller first demonstrated that these spaces were connected
with the lymphatic system, and that the contained fluid was lymph.
Although this fact was contradicted by Meyer it received confirma-
tion from Stannius, Leydig, and especially from Recklinghausen,
who showed that the fluid of the lymph-sacs was carried away by
the lymphatics, and that later it entered the blood-stream.

252 THE VASCULAR SYSTEM.

A. The Lymph-sacs of the Head and Trunk.

a. The septa. The connective-tissue septa themselves contain
sinuses which occupy the space between their two surfaces (Fig.
166): these septal sinuses receive the contents of the cutaneous
lymph-vessels and forward their contents into lymph-vessels situated
in the septa. Such a sinus is shown in transverse section in Fig.
166, which is a section of the ventral septum. 'The same sinus, in
plan, is seen in Fig. 167.

(1) The dorsal septum (Septum dorsale), (Figs. 169 and 171 d) of
each side commences at the tympanic membrane; it is then attached
to the MW. depressor mawillae, M. infraspinatus, and M. longissimus

Fig. 167.

Transverse section of a sep-
tum with the attached
skin, its contained sinus
injected with blue injec-

tion mass,
H Skin.
s Septum, The sinus abdominalis lateralis (Ecker) injected
S Sinus contained in the with blue mass.
septum.

H Skin with its lymph-vessels.
S Sinus of the septum with lymph-vessels
opening into it.
s The septum cut parallel with the skin.
dorsi; and continued backwards over the MW. obliquus abdominis
externus to the anterior end of the I. glutaeus, whence it extends
along the iliac bone, where it is connected with the posterior
lymph-heart and the MW. pyriformis, to the tip of the urostyle. At
the tip of the MW. g/utaeus it is joined by the iliac septum. The
posterior part of the septum is horizontal, and forms the roof of the
iliac lymph-sae.

(2) The ventral septum (Septum abdominale), (Figs. 169, 170, and
171 a), commencing at the Symphysis pubis, rans forwards and out-
wards, on either side, along the outer border of the MW. rectus abdom-
inis to the Portio abdominalis of the M. pectoralis (p’”’), where it is,
attached, at a right angle, to the pectoral septum; it then extends
forwards, after attachment to the axillary septum, to the outer

a a

_ symphysis pubis, where it joins the

THE LYMPHATIC SYSTEM. 253

angles of the maxillary septum. At the root of the anterior ex-_

tremity it divides to enclose the root of the limb, and so form the

axillary septum.

(3) The pectoral septum (Septum pectorale), (Figs. 170 and 171 p)
is attached to the superficial surface of the MV. pectoralis (Portio
sternalis, anterior and posterior); it rans transversely across the body,
and is attached at its outer end to the ventral and to the maxillary
septa. The septum passes obliquely backwards and downwards
to be attached to the skin, and so forms a very acute angle with
the HW. cutaneus pectoris (cp): a vertical band of connective-tissue,
broad behind, narrow in front, extends in the middle line from the
septum to the body wall; from it a certain amount of loose con-
nective-tissue extends in all directions,‘and forms open lymph-spaces
between the WM. cutanei pectorales and the vertical septum.

(4) The perineal septum (Septum
perineale), (Fig. 170 pe). This me-
dian septum extends from the at-
tachment of the dorsal septum to the
tip of the urostyle, backwards to the

Fig. 168.

ventral septa. In its attachment
it follows the middle line of the
perineum.

(5) The maxillary septum (Sep-
tum maxillare), (Figs. 170, 171 m)

is attached by either extremity Sinus thoracicus transversus (Ecker).
to the dorsal septum, near the cp M. cutaneus pectoralis,
tympanic membrane, is continued eens teewsaee

s Sinus with its afferent vessels.

downwards to unite with the

anterior end of the ventral septum, and then runs across the
anterior pectoral region, forming a curve with the convexity
forwards. It has inserted into it fibres of the M. submazillaris.
The septum is formed of very loose tissue, and frequently contains
deposits of fat; it encloses a well-marked septal sinus, the Sinus
thoracicus transversus (Ecker).

(6) The iliac septum (Figs. 169, 172 15, 173 S’) is a septum
extending from the dorsal septum to the inguinal septum. It is
attached to the dorsal septum opposite the anterior end of the
M. glutaeus, and extends outwards and downwards to the inguinal

254 THE VASCULAR SYSTEM.

Fig. 1691.

septum. In it
the IM. cutaneus
lacus passes
from the trunk
to the skin.

(7) The ingui-
nal septum (La-
mina inguinalis,
Ecker), (Figs.
169, 171, the
dotted line near
15) Fig - 172,
separates the
belly from the
thigh ; on the
ventral surface
it is attached to
the groove which

The lymph-sacs of Rana
esculenta, seen from the
dorsal surface.

t Dorsal lymph-sac.
3 Lateral lymph-sac,
7 Brachio-radial lymph-
sac,
9 Femoral lymph-sac.
ro Suprafemoral lymph-

sac.
11 Interfemoral lymph-
sac

12 Crural lymph-sac.

13 Dorsal lymph-sac of
the foot.

14 Plantar lymph-sac of
the foot.

15 Iliac lymph-sac.

a Ventral septum.

d Dorsal septum.

J’ Superior femoral sep-

tum.

J’ Intermediate femoral

septum.

i Inguinal septum.

s Posterior brachial sep-
tum.

s” Anterior brachio - ra-
dial septum.

V Vocal sac.

* In Figs. 168, 169, and 170 the dotted lines denote the boundaries of the various

lymph-sacs.

THE LYMPHATIC SYSTEM. 255

forms the boundary between the belly and thigh; on the dorsal
surface it is more posterior, and is attached to the dorsal surface of
the muscles of the thigh at some little distance from the trunk. © It
completely surrounds the root of the hinder limb. It has attached
to it the ventral, dorsal, and iliac septa, together with the septa
of the thigh.

b. The lymph-sacs.

(1) The dorsal lymph-sac (Saccus cranio-dorsa/is), (Figs. 169 and
1711). This is a large lymph-sac, extending from the tip of the
snout to the tip of the urostyle; it is bounded in front by the
attachment of the skin to the premaxillary bones; the line of
attachment is continued, on either side, along the inner border of
the external nares, then forms a pouch towards the jaw and in front
of the eye, and runs backwards along the upper border of the orbit,

_ where it is attached to the upper eyelid, to the inner border of

the tympanic membrane. In this course the skin is firmly attached
to the underlying parts. The lateral boundary of the lyniph-sac,
behind this point, is formed by the dorsal septum, which separates
it from the lateral lymph-sae.

(2) The ventral lymph-sac (Saccus abdominalis), (Figs. 170, 171 2)

_is triangular in form, with the base forwards at the breast, and the

apex behind at the pelvic symphysis ; it occupies the space between
the skin below and the belly muscles and part of the W. pectoralis
above. It is bounded anteriorly by the pectoral septum (y) and
laterally by the ventral septa (a).

(3) The lateral lymph-sac (Saccus Jateralis), (Figs. 169, 170, and
171 3) exists on either side; below, the sac is bounded by the.
ventral septum (a), above by the dorsal septum (@), anteriorly by the
maxillary septum (), and posteriorly by the inguinal septum (7) and
the wall of the iliac lymph-sac.

(4) The submaxillary lymph-sac (Saccus submazillaris), (Figs.
170 and 171 4) is a space between the M. submazillaris and the
skin; the sae is bounded behind by the maxillary septum, which
separates it from the pectoral lymph-sac, and more laterally from
the lateral lymph-sac. In front and at the sides the skin is firmly
attached to the margin of the mandible.

(5) The pectoral lymph-sae (Saccus thoracicus), (Figs. 170 and
171 5) lies between the submaxillary and ventral lymph-sacs.- The

256 THE VASCULAR SYSTEM.

Lymph-sacs of Rana esculenta, seen from the ventral surface.

2 Ventral lymph-sac. a Ventral septum, m’ Attachment of maxillary sep-
3 Lateral lymph-sac. a’ Anterior division of ventral tum to skin.
4 Submaxillary lymph-sac. septum. p Pectoral septum. ba
5 Thoracic lymph-sac. a” Posterior division of ventral p’” Port, abdom. of the M. pecto-
6 Brachio-ulnar lymph-sac. septum. ralis.
. 8 Anterior brachial lymph- ef Intermediatefemoralseptum. pe Perineal septum.
sac. cp M. cutaneus pectoris. .r M. rectus abdominis.
9 Femoral lymph-sac. ’ Inferior femoral septum, ri’ ‘M. rectus internus minor.
11 Intérfemoral lymph-sac, @ Inguinal septum. s” Anterior brachio-ulnar sep-
12 Crural lymph-sac. 7 Attachment of inguinal tum.
13. Dorsal lymph-sac of the septum to skin. s” Anterior brachial-radio sep-
foot m Maxillary septum, tum.

oot. t
14 Plantar lymph-sac of the foot. sm Muse, submaxillaris,

bs Yr

-

THE LYMPHATIC SYSTEM. 257

sac is bounded behind by the pectoral septum (y), and in front by
the maxillary septum (7).

(6) The iliac lymph-
sac (Saccus iliacus),
(Figs. 171 and 172 15,
173) does not really be-
long to the subcutane-
ous lymph-saes, as it
does not lie directly un-
der the skin except by a
very narrow border. It
is bounded in front by
the iliac septum, above
by the dorsal septum,
and posteriorly by the

inguinal septum. By
_ these boundariesaspace
is enclosed, which lies
under the dorsal septum
and dorsal sac, and at
the same time partly
under the lateral sac.
In this sac the WV.
glutaeus, the anterior
ends of the WM. vastus
externus, M. rectus an-
terior, and M. cutaneus
ilacus, lie free together

The lymph-sacs of Rana esculenta,
seen from the side.

AB Souew nen
z
=
3

~

Attachment of M. submaxil-
laris to the skin.

Pectoral septum.

M. submaxillaris.

Vocal sac.

*3*

258 THE VASCULAR SYSTEM.

with the hindmost part of the I. obliquus abdominis -externus,
and the hinder portion of the posterior lymph-heart. Anteriorly
the floor is depressed between the MM. obliquus abdominis and the
M. glutaeus, the depression leading to a canal, which communicates
with the abdominal cavity.

B. The Lymph-sacs of the Anterior Extremity.

a. The septa.

(1) The axillary septum (Septum amillare), (Figs. 170 a’, a”,
171) is practically a portion of the ventral septum, which divides
at the root of the arm to enclose it. The dorsal and ventral por-
tions of this circular septum have received special names.

a. The dorsal axillary septum
Bie. 47- (Septum axillare dorsale) crosses the

M. triceps and joins the pectoral
_ septum.
: B. The ventral axillary septum

(Septum axillare dorsale) passes

through the axilla and joins the

Transverse section through the trunk in the pectoral septum.
region of the iliac ]ymph-sac. : .
_ en The circular axillary septum has

¢ Urostyle. ‘ :

ce’ Skin. attached to it the following :—

o Muscles of abdominal wall.

x: Dorsal lymph-sac. (2) The posterior brachial sep-

3 Lateral lymph-sac.
15 Iliac lymph-sac,

tum (Septum brachiale posticum (Fig.
169 s); it is attached along the
middle line of the extensor surface of the arm (long head of the
M. triceps) to the elbow and to the forearm (J/M. anconaez), then passes
obliquely over the volar surface of the hand to the fourth finger.

(3) The anterior brachio-ulnar septum (Septum brachiale anticum
ulnare), (Fig. 170s”) commences at the same point as the foregoing,
passes obliquely over the outer head of the MW. triceps, and is con-
tinued over the W/. flexor antibrachii lateralis, M. supinator longus, and
M. extensor digitorum communis, to the dorsal surface of the fourth
finger.

(4) The anterior brachio-radial septum (Septum brachiale an-
ticum radiale), (Fig. 170 8’) passes from the outer angle of the wall
of the pectoral lymph-sac, over the inner head of the J/. triceps and
M. flexor carpi radialis to the thumb.

b. The lymph-sacs are enclosed by these three septa; they are
four in number :—

i oe e+ er

THE LYMPHATIC SYSTEM. 259

(1) The brachio-ulnar lymph-sae (Saceus brachialis ulnaris),
(Fig. 170 6) is situated between the first and second septa along the
extensor and ulnar surfaces.

(2) The brachio-radial lymph-sac (Saccus
brachialis radialis), (Fig. 169 7) is placed
along the extensor and radial surfaces.

(3) The anterior brachial lymph-sac
(Saceus brachialis anticus), (Fig. 170 8) lies
on the flexor surface between the second
and third septa; it is a long cavity and in-
terrupted by connective-tissue bands, in
which the tendon of the W. sterno-radialis
and the nerve and vessels are situated.

(4) The axillary lymph-sae (Saceus azil-
laris) corresponds to the iliac lymph-sac ;
it is bounded by the divisions of the ventral
septum.

In the hand no large lymph-space exists ;
the skin is attached by numerous bands to
the underlying structures.

C. The Lymph-saes of the Hinder Ex-
tremity.

a. The septa.

(1) The superior femoral septum (Sep-
tum femorale superius), (Figs. 169 and 175 tT)
is attached above to the inguinal septum
near the posterior lymph-heart; and is
continued, from this point, over the M. rastus erternus and along
the WM. triceps to the knee.

(2) The inferior femoral septum (Septum femorale inferius), (Figs.
170 and 175”) runs from the inguinal septum near the point
of insertion of the M. rectus abdominis, along the

A E ' Fig. 174.
M. rectus internus minor to the knee.

(3) The intermediate femoral septum (Septum |
Semorale intermedium), (Figs. 169 and 175’) passes '
from near the posterior lymph-heart over the
M. semimembranosus and the M. rectus internus minor a ee
to jom the inferior femoral septum. rn

$2

Fig. 173-

moral, inguinal,
and perineal septa-

260 THE VASCULAR SYSTEM.

(4) The tibio-femoral septum (Septum femoro-crurale) is a circular
band, separating the lymph-saes of the thigh from the leg sae.

(5) The septa of the foot. At the ankle joint the skin is closely
attached all round to the underlying parts. Along the outer border
of the foot a septum is attached to the skin externally, and to the
underlying parts, especially the IM. abductor longus digiti primi,
internally. A similar but weaker band is attached along the outer
border of the foot, especially to the MW. adductor digiti quinte.

b. The lymph-sacs.

(1) The femoral lymph-sae (Saccus femoralis), (Figs. 169, 170,
171, 175 9) covers the lower and outer surfaces of the thigh; it is
bounded by the superior femoral and
inferior femoral septa, and in front
by the inguinal septum.

(2) The suprafemoral lymph-sac
(Saccus suprafemoralis), (Figs. 169,
171, 175 10) lies on the upper sur-
face of the thigh, between the

ve pte ete superior and intermediate femoral
Transverse section of the thigh. septa ; above it is bounded by the
b M. biceps. non
f’ — Superior femoral septum. inguinal septum.
f”’ Inferior femoral septum. he i m e
jt’ Intermediate femoral septum. (3) T sg interfe oral lymph ene
H Skin, (Saccus interfemoralis), (Figs. 169,
vi! M. rectus internus major. :
OE. catia Eakecste nition. 170, 175 11) is a narrow sac on the
ee inner surface of the thigh, between
sm . semimembranosus. -
ve M. vastus externus. the inferior femoral septum and the
g Femoral lymph-sac. : ‘
io. Supeatieione ipeaioue. intermediate femoral septum. It
12“) Interiemorad tymape a0. covers the MW. rectus internus minor,

and is interrupted by numerous bands of tissue which pass from the
surface of the muscle to the skin. It is, therefore, not a simple sac,
but a very wide-meshed trabecular structure of connective-tissue.
The sac is triangular in shape, with the base directed forwards at
the inguinal septum.

(4) The lymph-sac of the leg is a simple sac enclosing the
whole leg, bounded above by the tibio-femoral septum, and below by
the attachment of the skin to the ankle.

(5) The lymph-saes of the foot. On the dorsum of the foot the
skin is free, and there is consequently a lymph-sac. On the plantar
surface the skin is attached by numerous connective-tissue bands
and thread-like tendons, particularly to the flexor tendons. The

a ieee ae mil

THE LYMPHATIC SYSTEM. 261

skin of the dorsal and plantar surfaces meet on the web and
enclose a very rich anastomosis of lymph-capillaries.

2. The Lymph-Hearts.

The frog has two pairs of lymph-hearts, one pair anterior, the
other posterior.

A. The anterior lymph-hearts (Fig. 176). These organs lie,
one on each side, behind the broad transverse processes of the third
vertebra (Miller, Panizza, Priestley), in a deep triangular space
formed by the separation of the fibres of the W. intertransversarius,
between the transverse processes of the third and fourth vertebrae.
Each heart is a rounded sac, slightly elongated anteriorly where

Fig. 177.

The anterior lymph-hearts.
IL The left anterior lymph-
heart. "
is. M. levator scapulae. The posterior lymph-hearts.
N Brachial nerve. ; gt =M. glutaeus.
ts. M. — transverso - scapularis ie M. ilio-coceygeus.
maior. LIC Posterior 1 -hearts.
1-4 Vertebrae numbered from p M. se rig
before backwards. r M. rectus.

ve M. vastus externus.

it is connected with the subscapular vein. [The hearts receive
lymph from the anterior part of the body and the surrounding
parts, and empty their contents into the vertebral vein. Each of
these hearts is supplied by a branch from the second spinal nerve
(Volkmann, Eckhard, Schiff, Priestley).]

B. The posterior lymph-hearts (Fig. 177) are situated on either
side of the urostyle in the triangular spaces (Miller, Panizza,
Priestley), bounded externally and above by the MW. g/utaeus,

262 THE VASCULAR SYSTEM.

internally and above by the J. coccygeo-iliacus, below and exter-
nally by the origin of the I/. vastus eaternus, and below by the
M. pyramidatis. Each posterior heart is about two lines long and
one broad, with its long axis placed antero-posteriorly ; the outer
surface is uneven and appears to be unequally dilated. The lymph-
heart is closely attached to the surrounding parts, especially to
the fascia covering the I. c/ii-coccygea, and posteriorly to the
M. levator ani and the M. pyramidalis. [The posterior lymph-hearts
receive lymph from the parts surrounding them, and from the
hinder extremities, and forward it into the /. c/iaca communicans.

The posterior lymph-hearts are each supplied by a branch from
the corresponding coceygeal nerve (Waldeyer) by its dorsal branch.
The lymph-hearts are also in close connection with the sympathetic
system (Waldeyer).] ;

PART III.

THE BLOOD, LYMPH, AND HISTOLOGY OF
THE VESSELS,

[The parts described in this section will be considered very
briefly, and only from an anatomical point of view.

A. The blood !.

The blood varies in colour, according as it is obtained from an
artery or from a vein; from an artery it has a bright red or scarlet
colour ; from a vein a darker shade: in the pulmonary vessels these
colours are reversed. The blood consists of a fluid plasma which
contains red and white corpuscles: the whole forming a slightly
alkaline, opaque, and somewhat sticky fluid.

a. The plasma or /iguor sanguinis is a transparent, clear, slightly
yellow fluid, faintly alkaline in reaction.

1 Mr. Hurst has noticed a frog (R. temporaria) in which the blood was perfectly
colourless.

SS as ee i <a

THE BLOOD, LYMPH, AND HISTOLOGY OF THE VESSELS. 263
b. The corpuscles are of two kinds, colourless and coloured.

~ (1) The colourless or white corpuscles are subspherical masses of
protoplasm, endowed with the power of spontaneous motion. They
are much fewer than the red corpuscles, though the proportion of
white to red varies considerably. Three chief varieties of colourless
corpuscles can be distinguished, all of which are true cell forms,
and behave like other cells with staining or other reagents. They
have no cell-wall, but are simply nucleated masses of protoplasm.
These corpuscles possess the power of passing through the walls
of the blood-vessels, and are then known as migratory cells; such
migratory cells can be found in nearly all tissues, but more espe-
cially in the connective-tissues.

a. Ordinary large colourless corpuscles are large transparent
masses of protoplasm containing one or two nuclei, rarely three
or more. The cell contains few granules, and usually has one or
more vacuoles or clear spaces containing fluid.

8. Granular corpuscles are less numerous than the foregoing, but
larger, and are distinguished by the numerous large dark granules
which they contain. The processes such a corpuscle sends out are
hyaline.

y- Smaller corpuscles also occur varying much in form: they may
consist of a nucleus with a very small amount of hyaline or granu-
lar protoplasm, or of several nuclei with an extremely small amount
of protoplasm.

(2) The coloured corpuscles are much more numerous than the
colourless corpuscles; each is a bi-coneave, oval disc, about
00255 mm. in length, and 0-017 mm. in breadth (Gulliver)!
(R. temporaria, 0°0235 and 00145 mm. respectively). Each cor-
puscle possesses an oval nucleus (Hewson)?, which projects into
either concave surface of the whole corpuscle. These corpuscles
do not possess the power of spontaneous movement; and have no
cell-wall. The corpuscles are of a reddish-yellow colour, and
give the blood its characteristic hue. The colouring matter is
haemoglobin, and when separated it crystallizes in prisms (Preyer).
The corpuscles show a well-marked intracellular and intranuclear
network. |

* Gulliver, Proc. Zool. Soc. London, 1845, Vol. XIII, p. 93 seq.
* Hewson, Phil. Trans. 1773, Vol. LXIII, p. 310 seq.

264 THE VASCULAR SYSTEM,

B. [The Lymph and Chyle.

The lymph is that portion of the blood which has filtered from
the blood-vessels, through the tissues, into the lymphatics. It is a
clear, transparent fluid, containing colourless corpuscles, which agree
in all particulars with the colourless corpuscles of the blood. During
digestion the lymph from the alimentary canal contains particles of
fatty matter, and is then known as chyle.| The colourless cor-
puscles of the lymph frequently contain portions of red corpuscles
or granules of pigment. Non-nucleated masses of protoplasm and
decolourised red corpuscles (slightly diminished in size) have also
been described as occurring frequently in the lymph (Fuchs*).]

C. [Histological Remarks on the Vascular System.
a. The heart has already been described (pp. 216-222).

b. The blood-vessels present the same structure as the corre-
sponding vessels in higher animals. The arteries and veins have
each the three walls or layers usually described—TZwnica adventitia,
Tunica media, and Tunica intima. The only characteristic to be men-
tioned is that the Tunica adventitia contains branched, pigmented
corpuscles. The Nervi vasorum, especially of the smaller arteries,
are arranged in two plexuses, one in the Zuxica adventitia (His) ?,
the second in the muscular coat (J. Arnold)*. The fibres of both
plexuses are non-medullated, and have the usual beaded appearance ;
they communicate freely with each other, The capillaries present,
as a rule, the usual structure: such special arrangements of the
capillaries or peculiarities in structure as occur will be described
with the organs in which they are found.

ce, The subcutaneous lymph-sacs are lined with a layer of
endothelium resembling the endocardium shown in Fig. 140; the
endothelial layer possesses stomata (see peritoneum), through which
the lymph-sacs communicate with the underlying lymphatics. The
endothelium is continued on to the vessels, nerves, ete., which
course through the sacs, and excludes these from the cavities. As a
rule an artery, vein, and nerve are enclosed in a common sheath.

d. The lymph-hearts are small saccular bodies with thin trans-
parent walls, which contain obscurely striated muscle-fibres. The
vessels communicating with the hearts appear to possess valves

1 Fuchs, Virchow’s Arch. 1877, Vol. LXXI, p. 78 seq.
? His, Virchow’s Arch. 1863, Vol. XXVIII, p. 427.
-§ Arnold, in Stricker’s Handbuch d. Gewebelehre, p. 137.

ee a —<« se

THE BLOOD, LYMPH, AND HISTOLOGY OF THE VESSELS. 265

(Miller). The walls of the hearts are formed of three layers; an
external, compared by Waldeyer to an adventitia, a muscular layer,
and an endothelial lining. The muscular fibres form a close inter-
lacing mass, the fibres being small, branched (Leydig), and pos-
sessed of many nuclei. Among the muscular fibres are pigmented
corpuscles, together with medullated and non-medullated nerve-
fibres, but no ganglion-cells (Volkmann, Waldeyer, Priestley).
The adventitia is a connective-tissue layer with many pigment

cells (Leydig, Hyrtl, Waldeyer).]

SECTION V.

THE ALIMENTARY TRACT WITH ITS APPENDAGES,
THE SPLEEN, AND THE PERITONEUM.

THE ALIMENTARY TRACT, ETC.

LITERATURE.

THE MOUTH.
(Except the mucous membrane of the tongue, for which see organ of taste.)

Ducrotay de Blainville, H. M., Ostéographie ou description iconographique
comparée du squelette et du syst?me dentaire des cing classes d’animaux vertébrés.
Paris, 1841.

Erdl, Ueber den Bau der Ziahne bei den Wirbelthieren, etc. Miinchen, 1841,

Fixen, C., De linguae raninae structura. Dorpat, 1857.

Heincke, F., Untersuchungen iiber die Zihne niederer Wirbelthiere. Zeitsch. f.
wiss. Zool. 1873. Vol. XXIII, p. 495.

Hertwig, O., Ueber das Zahnsystem der Amphibien, etc. Suppl. to Vol. XI,
Arch. f. mik. Anat. 1874.

Hoffmann, C. K., Bronn’s Thierbuch. Leipzig and Heidelberg, 1873-1878. Vol.
VI, p. 379.

Holl, M., Zur Anatomie der Mundhéhle von Rana temporaria. Wiener Acad.
Sitzungsb. 1887. Vol. XCV, Pt. ITI, p. 47. :

Hoyer, Ueber die Epithelzellen der Froschzunge, sowie iiber den Bau der Cylinder-
und Flimmerepithelien und ihr Verhiiltniss zum Bindegewebe. Arch. f. Anat,
u. Physiol. 1858, p. 163; also Deutsche Klinik, 1857.

Langer, C., Ueber das Lymphgefiisssystem des Frosches. Wiener Acad, Sitzungsb.
1867. Vol. LV, Pt. I, pp. 614-621.

Leydig, Die Anuren Batrachier der deutschen Fauna. Bonn, 1877.

Owen, R., Odontography. London, 1840-1845, p. 187.

Reichel, P., Beitriige zur Morphologie der Mundhohlendriisen der Wirbelthiere.
Leipzig, 1882; also in Morph, Jahrb, 1882, Vol. VIII, pp. 1-72.

Santi Sirena, Untersuchungen iiber den Bau und die Entwicklung der Zihne bei
den Amphibien und Reptilien. Verhandl. d. phys.-med. Gesellsch. in Wiirz-
burg, 1872. Vol. II, new series, p. 125.

Schobl, J., Ueber divertikelbildende Capillaren in der Rachenschleimhaut nackter
Amphibien. Sitzungsb. d. k. b. Gesellsch. d. Wiss. in Prag. 1878, p. 25;
also in Arch, f. mik. Anat. 1885, Vol. XXV, p. 89.

Schultze, F. E., Das Driisenepithel der schlauchformigen Driisen des Diinn- und
Dickdarms und die Becherzellen (of the pharyngo-oral cavity). Centralbl. f. d.
med. Wiss. 1866, p. 61.

Schultze, F. E., Epithel- und Driisen-Zellen. Arch. f. mik. Anat. 1867. Vol. ITI,
P- 137:

Smith, W. J., Beitrag zur differentiellen Diagnose der Rana fusca s. platyrrhinus
und Rana arvalis s. oxyrrhinus auf Grund der an den Gaumenzihnen nachweis-
baren Unterschiede. Pfliiger’s Arch. f. d. ges. Physiol. 1883. Vol. XXXII,
pp. 581-588.

LS

LITERATURE. ; 269

Tomes, C. S., On the development of the teeth of the newt, frog, slowworm, and
green lizard. Phil. Trans. 1874, p. 285.

Térék, Untersuchungen iiber die Entwickelung der Mundhéhle, ete. Wiener
Sitzungsb. 1866. Vol. LIV, Pt. I, p. 75-

Waller, A., Microscopic examination of the principal tissues of the tongue, ete.
Phil. Mag. 1846, pp. 273-290.

Waller, A., On the development of the mouth and tongue of the frog. Phil. Mag.
1850. Vol. I, pp. 38-43.

Zeller, A.. Die Abscheidung des indig.-schwefelsauren Natrons in den Driisen (In-
termaxillary gland). Virchow’s Arch. 1878. Vol. LX XIII, p. 257.

THE OESOPHAGUS AND STOMACH.

Biedermarn, Untersuchungen iiber Magenepithel. Wiener Acad. Sitzungsb. 1875.
Vol. LXXT, Pt. IL, p. 377.

Bischoff, Ueber den Bau der Magenschleimhaut. Arch. f. Anat.u. Physiol. 1838,
p- 503.

Bleyer, E., Magenepithel und Magendriisen der Batrachier. Dissert. Kénigsberg,
1874.

Braun, Zum Vorkommen von Flimmerepithel im Magen. Zool. Anzeiger. 1880.
No. 69, p. 568.

Brinton, in Cyclopaedia of Anat. and Physiol., edited by R. B. Todd. 1859. Vol. I,
p- 320.

Cobelli, Le gliandole acinose del cardia. Wiener Acad. Sitzungsb. 1866. Vol.
LIT, Pt. I, p. 251.

Ebstein, W., Beitrige zur Lehre vom Bau und den physiologischen Funktionen
der sogenannten Magenschleimdriizen. Arch. f. mik. Anat. 1870. Vol. VI,
p- 515. ‘

Ecker, A., Ueber die Driisen der Magenschleimhaut. Zeitsch. f. rat. Med. 1852,
P- 243-

Foster, M., On some points in the epithelium of the frog’s throat. Journ. of Anat.
and Physiol. 1869. Vol. IV, p. 394.

Frerichs, On the Stomach, in Wagner’s Handwiérterbuch d. Physiol. 1848. Vol. IT,

p. 748.

Glinsky, A., Zur Kenntniss des Baues der Magenschleimhaut der Wirbelthiere.
Centralbl. f. d. med. Wiss. 1883, p. 225.

Gonjaew, K., Die Nerven des Nahrungsschlauches. Arch. f. mik. Anat. 1875. Vol.
XI, pp. 479-496.

Hebold, O., Ein Beitrag zur Lehre von der Sekretion und Regeneration der
Schleimzellen. Dissert. Bonn, 1879, pp. 21-27.

Heidenhain, R., Untersuchungen iiber den Bau der Labdriisen. Arch. f. mik. Anat.
1870. Vol. VI, p. 368. :

Hoffmann, C. K., Bronn’s Klassen und Ordnungen des Thierreichs. Leipzig und
Heidelberg. 1873-1878. Vol. VI, pp. 408-412.

Just, A., Zur Histologie und Physiologie des Flimmerepithels. Breslauer irztliche
Zeitsch. 1885. No. 18, pp. 205-206. _

Klein, E., Darmkanal, in Stricker’s Gewebelehre, p. 388, etc.

v. Kolliker, A., Mikroskopische Anatomie, 1854. Vol. IT, p. 147. -
Langley, J. N., and Sewall, H., On the changes in pepsin-forming glands during
secretion. Journ. of Physiol. 1880. Vol. II, pp. 261, 281.
Langley, J. N., On the histology and physiology of pepsin-forming glands. Phil.

Trans. 1881. Vol. CLX XII, Pt. ITI, pp. 663-712.

270 THE ALIMENTARY TRACT, ETC.

Langley, J. N., On the structure of secretory cells and on changes which take place

in them during secretion. Internat. Monatschr. f. Anat. u. Histol. Vol. I,

pp: 69-76.

Leydig, Lehrbuch der Histologie. 1857.

Nussbaum, M., Ueber den Bau und die Thiitigkeit der Driisen. Arch. f. mik.
Anat. 1882, Vol, XXI, p. 296; 1882, Vol. XXVIII, p. 296; 1877, Vol. XIII,
p- 721.

Partsch, C., Beitriige zur Kenntniss des Vorderdarmes einiger Amphibien und
Reptilien. Arch. f. mik. Anat. 1877. Vol. XIV, p. 179.

Regéczy, E. N., Ueber die Epithelzellen des Magens. Arch. f. mik. Anat. 1880.
Vol. XVIII, pp. 408-411.

Robinson, C., Ueber die Lymphgefiisse der Abdominaleingeweide des Frosches, etc.
Froriep’s Notizen, 1846. No. 807, col. 225.

Rollett, Bemerkungen zur Kenntniss der Labdriisen und der Magenschleimhaut.
Untersuch. in d. Institut f Physiol. u. Histol. zu Graz. 1871.

Schultze, F. E., Epithel- und Driisenzellen. Arch. f. mik. Anat. 1867. Vol. ITI,
p. 174; abstract in Centralbl. f. med. Wiss. 1866, No. 4.

Schmidt, C., Ueber eingenthiimliche aus dem Flimmerepithel hervorgehende Gebilde.
Arch. mik. Anat. 1881. Vol. XX, p. 123.

Sewall, H., A note on the processes concerned in the secretion of the pepsin-
forming glands of the frog. Studies in the Biol. Laborat., Johns Hopkins
Univers. Vol. II, pp. 131-134.

v. Swiecicki, H., Untersuchungen tiber die Bildung und Ausscheidung des Pepsins
bei den Batrachiern. Pfliiger’s Arch. f. d. ges. Physiol. 1876. Vol. XIII,
P- 444-

Trinkler, N., Zur Kenntniss des feineren Baues der Magenschleimhaut, insbesondere
der Magendriisen. Centralbl. f. med. Wiss. 1883, pp. 161-163.

Trinkler, N., Ueber den Bau der Magenschleimhaut. Arch. f. mik. Anat. 1885.
Vol. XXIV, p. 74.

Tritschel, Ueber die Endigung der Nerven in der Schleimhaut des Magens.
Centralbl. f. d. med. Wiss. 1870, p. 115.

Valatour, Recherches sur les glandes gastriques et sur les tuniques musculaires du
tube digestif dans les poissons ossieux et les Batraciens. Annales de Sc. nat.
1861. Series TV. Vol. XVI, p. 2109.

THE INTESTINE.

Arnstein, C., Ueber Becherzellen, etc. Virchow’s Arch. 1867. Vol. XXXIX,
p- 527-

Arnstein, C., and Gonjaew, K., Ueber die Nerven des Verdauungskanals. Pfliiger’s
Arch. f. d. ges. Physiol. 1874. Vol. VIII, pp. 614-615.

Auerbach, L., Fernere vorliufige Mittheilung iiber den Nervenapparat des Darmes.
Virchow’s Arch. 1864. Vol. XXX, p. 457.

Auerbach, L., Untersuchungen iiber Lymph- und Blutgefiisse. Virchow’s Arch.
1865. Vol. X XXIII, p. 340.

Auerbach, L., Organologische Studien.

Billroth, T., Ueber die Epithelzellen der Froschzunge ; der Bau, Cylinder- und Flim-
merepithel und ihr Verhiiltniss zum Bindegewebe. Arch. f. Anat. u. Physiol.
1858, p. 159.

Billroth, T., Einige Beobachtungen iiber das ausgedehnte Vorkommen von

Nervenanastomosen im Tractus intestinalis. Arch. f. Anat. u. Physiol.
1858, p. 148.

—OC.:

LITERATURE. 271

Brettauer und Steinach, Untersuchungen iiber das Cylinderepithelium. Wiener
Akad. Sitzungsb. 1857. Vol. XXIII, p. 303. Moleschott’s Zeitsch. 1857.
Vol. II, p. 157.

Darsch, O., Beitriige zur Kenntniss des feineren Baues des Diinndarmes. Wiener

b. 1880. © Vol. LX XXIT, Pt. ITT, p. 168.
Dénitz, Ueber die Schleimhaut des Darmcanals. Arch. f. Anat. u. Physiol. 1864,
. 367.

Danits, Ueber Darmzotten. Arch. f. Anat. u. Physiol. 1866, p. 757.

Eberth, C. J., Ueber den feineren Bau der Darmschleimhaut. Wiirzb. naturw.
Zeitschr. 1864. Vol. V, p. 23.

Eimer, T., Zur Fettresorption, ete. Virchow’s Arch. 1867. Vol. XXXVIII,
p. 428.

Bimer, T., Ueber Becherzellen. Virchow’s Arch. 1868. Vol. XLII, p. 490.

' Eimer, T., Zur Geschichte der Becherzellen. Dissert. 1867.

Eimer, T., Die Wege des Fettes in der Darmschleimhaut bei seiner Resorption.
Virchow’s Arch. 1869. Vol. XLVIII, p. 119.

Eimer, T., Zur Becherfrage. Virchow’s Arch. 1867. Vol. XL, p. 282.

Erdmann, Die Resorptionswege in der Schleimhaut des Diinndarms. Dissert.
Dorpat, 1867.

Fries, E., Ueber die Fettresorption und die Entstehung der Becherzellen. Virchow’s
Arch. 1867. Vol. -XL, p. 519.

Gerlach, L., Ueber den Auerbachschen Plexus mysentericus. Arbeiten aus d.
physiol. Anstalt.. Leipzig. 1872, pp. 102-112.

Gonjaew, K., Die Nerven des Nahrungsschlauches. Arch. f. mik. Anat. 1875. Vol.
XI, pp. 479-496.

Gruby and Delafond, Résultats des recherches faites sur l’anatomie et les
fonctions des villosités intestinales, ete. Compt. rend. 1843. Vol. XVI,
Pp. 1194-

Grugenhagen, A., Ueber Fetiresorption und Darmepithel. Arch. f. mik. Anat.
1887. Vol. XXIX, p. 139.

Heidenhain, R., Die Absorptionswege des Fettes. Moleschott’s Untersuchungen.
1858. Vol. TV, p- 251.

Henle, J., Symbolae ad anatomiam villorum intestinalium impr. eorum epithelii
et vasorum lacteorum. LBerolini, 1837.

Hoffmann, C. K., Bronn’s Klassen und Ordnungen des Thierreichs. Leipzig und
Heidelberg, 1873-1878. Vol. VI, pp. 412-424.

Klein, E., Der Darmkanal in Stricker’s Gewebelehre, Article XVI.

Klein, E., Contributions to the anatomy of Auerbach’s Plexus in the intestine of the
frog and toad. Quart. Journ. Micros. Sci. 1873. Vol. XIII, p. 377.

Klein, E., and Verson, E., Der Darmeanal, in Stricker’s Gewebelehre, 1871,
P- 355- :

Klein, E., Der neue Nervenapparat v. Thanhoffer’s. Centralbl. f. d. med. Wiss,
1883, p. 82.

v. Kélliker, A., Nachweis eines besonderen Baues der Cylinderzellen des Diinndarms.
Verhandl. d. phys.-med. Gesells. Wiirzburg, 1856. Vol. VI, p. 153.

v. K6lliker, A., Handbuch der Gewebelehre.

Lambl, Ueber die Epithelialzellen der Diinndarmschleimhaut. Wiener med.
Wochenschr. 1859. Nos. 24 and 25.

Langer, C., Ueber das Lymphgefiisssystem des Frosches: Wiener Acad. Sitzungsb.
1866. Vol. LIII, Pt. I, p. 395.

Letzerich, L., Ueber die Resorption der verdauten Nahrstoffe im Diinn-
darm. Virchow’s Archiv. 1866, Vol. XXXVII, p. 232; 1867, Vol. XXXIX,
P- 435-

Lipsky, A., Beitrag zur Kenntniss des feineren Baues des Darmcanals. Wiener
Akad. Sitmabigeb 1865. Vol. LV, Pt. I, p. 183.

272 THE ALIMENTARY TRACT, ETC.

Oeffinger, Einige Bemerkungen iiber die sogenannten Becherzellen. Arch. f. Anat.
u. Physiol. 1867, p. 337.

Partsch, C., Beitriige zur Kenntniss des Vordariavaaa einiger Amphibien und
Reptilien. Arch. f. mik, Anat. 1877. Vol. XIV, p. 179.

Remak, R., Ueber peripherische Ganglien an den Nerven des Nahrungsrohrs. Arch.
f. Anat. u. Physiol. 1858, p. 189; also in Zeit. d. Vereins f. Heilkunde in
Preussen. 1840.

Renzoni, Osservazioni e ricerche sul epitelio intestinale.. Rendiconti dell Acad. di
Napoli. 1868.

Rusconi, Riflessioni sopra il sistema linfatico dei rettili. Pavia, 1845.

Sachs, J., Zur Kenntniss der sogenannten Vacuolen oder Becberseliens im Diinndarm.
Virchow’s Arch. 1867. Vol. XXXIX, p. 493.

Schultze, F. E., Das Driisenepithel der schlauchférmigen Driisen des Diinn-
und Didkdacens und die Becherzellen. Centralbl. f. d. med. Wiss. 1866,
p- 160.

Schultze, F. E., Epithel- und Driisen-Zellen. Arch. f. mik. Anat. 1867. Vol. ITI,
Pp. 145-

Thanhoffer, L., Beitriige zur Fettresorption und histologischen Structur der
Diinndarmzotten. Brita Arch. f. d. ges. Physiol. 1874. Vol. VIII, pp.
391-443.

v. Thanhoffer, L., Ein neuer Nervenapparat im Diinndarm. Centralbl. f. d. med.
Wiss. 1883, p. 33.

v. Thanhoffer, L., Antwort auf Herrn Prof. Klein’s ‘ Der neue Nervenapparat ete.,”
betitelte Demnsrkenets Centralbl. f. d. med. Wiss. 1883, p. 176.

Valatour, M. M., Recherches sur les glandes gastriques et sur les tuniques musculaires
du tube digestif dans les poissons et les Batraciens. Annales des Sci. nat. 4th
Series, Vol. XVI. Zool. 1861, pp. 219-285.

Watney, H., The minute anatomy of the alimentary canal. Phil. Trans. 1877.
Vol. CLXVI, Pt. II, p. 451.

Wiegandt, Untersuchungen iiber das Diinndarmepithel. Dissert. Dorpat, 1860.

v. Wittich, Beitriige zur Frage iiber Fettresorption. Virchow’s Arch. 1857. Vol.

XI, p. 37.

THE LIVER, GALL-BLADDER, AND PANCREAS.

Barfurth, D., Vergleichend-histochemische Untersuchungen iiber das Glycogen.
Arch. f. silks Anat, 1885. Vol. XXV, p. 369.

Brotz, J., and Wagenmann, C. A., De sumphibloraca hepate et cleudalarina ductu
aucehio carentium structura dague earundem functionibus experimenta.
Berolini, 1841.

v. Brunn, A., Flimmerepithel in den Gallengingen des Frosches. Zool, Anzeiger.
1883. No. 148, p. 483.

Eberth, C. J., Die Pigmentleber der Frésche und die Melaniimie. Virchow’s Arch.
1867. Vol. XL, p. 305.

Eberth, C. J., Zur Kenntniss der Verbreitung glatter Muskeln. Zeitschr, f. wiss.
Zool. 1863. Vol. XII, p. 360.

Eberth, C. J., Ueber den feineren Bau der Leber. Centralbl. f. d. med. Wiss.
1866, p. 897.

Eberth, C. J., Untersuchungen fiber die Leber der Wirbelthiere. Arch. f. mik.
Anat. 1867. Vol. III, p. 423.

Eberth, C. J., Untersuchungen iiber die normale und pathologische Leber. Vir-
chow’s Arch. 1867. Vol. XX XIX, p. 7o.

——

“

LITERATURE. 273

berth, C. J., Ueber die Pigmentleber der Frésche. Virchow’s Arch. 1862. Vol.

XXIX, p. 70.
Gerlach, L., Ueber die Nerven der Gallenblase. Centralbl. f.d. med. Wiss. 1873,
p- 562.

Hering, E., Ueber den Bau der Wirbelthierleber. Wiener Acad. Sitzungsb. 1886.
Vol. LIV, Pt. I, p. 335-

Hering, E., Ueber den Bau der Wirbelthierleber. Arch. f. mik. Anat. 1867. Vol.
II, p. 88. ;

Hering, E., On the liver. Stricker’s Gewebelehre. 1872, p. 429.

Hoffmann, C. K., Bronn’s Klassen und Ordnungen des Thierreichs. Leipzig und
Heidelberg, 1873-1878. Vol. VI, p. 424.

Jones, C. H., On the structure and development of the liver. Phil. Trans. 1849.
Pt. I, p. 122.

Langley, J. N., On variations in the amount and distribution of fat in the liver-cells
of the frog. Proc. Roy. Soc. 1886. Vol. XX XIX, p. 234.

Leydig, F., Lehrbuch der Histologie. 1857.

Leydig, F., Die Leber der Fische und Batrachier.

Nussbaum, M., Ueber den Bau und die Thatigkeit der Driisen (Pancreas). Arch.
f. mik. Anat. 1877. Vol. XIII, p. 752.

Popoff, M., The nerves of the gall-bladder (in Russian). Rudneff’s Journ. f.
normal. u. pathol. Histol., ete. 1872.

Remak, R., Ueber runde Blutgerinnsel und iiber pigmenthaltige Zellen. Arch. f.
Anat. u. Physiol. 1852, p. 115.

Weber, E. H., Ueber die periodische Farbenanderung welche die Leber der Hiihner
und Friésche erleidet. Bericht von Verhandl. K. Sach Gesell. Leipzig,
1850, p. 15.

Zeller, A., Die Abscheidung des indig.-schwefelsauren Natrons in den Driisen
(Pancreas}. Virchow’s Arch. 1878. Vol. LX XIII, p. 257.

THE SPLEEN.

Billroth, T., Beitrage zur vergleichenden Anatomie der Milz. Arch. f. Anat. u.
Physiol. 1857, p. 88.

Billroth, T., Beitrage zur vergleichenden Anatomie der Milz. Virchow’s Arch.
1861, Vol. XX, p. 410, and 1862, Vol. XXIII, p. 457; also Zeitschr. f. wiss.
Zool. 1862, Vol. XI, p. 325.

a onE = in Wagner’s Handworterbuch der Physiologie. 1849.

Gray, H., On the structure and use of the spleen. London, 1854.

cea” C. K., Bronn’s Thierbuch. Leipzig und Heidelberg, 1873-1878. Vol.

» P- §09-.

v. Kolliker, A., Ueber den Bau und die Verrichtungen der Milz. Mittheil. d. naturf.
Gesell. in Ziirich, 1847. Vol. I, p. 120.

Kusnezoff, F., Ueber blutkérperchenhaltige Zellen der Milz. Wiener Sitzungsber.

: 1873. Vol. LXVII, Pt. III, pp. 58-67.

Miller, W., Ueber den feineren Bau der Milz. Leipzig und Heidelberg, 1865.

Remak, R., Ueber runde Blutgerinnsel und ‘fiber pigmenthaltige Zellen. Arch. f.
Anat. u. Physiol. 1852, p. 115.

Schweigger-Seidel, F., Untersuchungen iiher die Milz. Virchow’s Arch. 1862.
Vol. XXII, p. 526.

Stieda, L., Zur Histologie der Milz. Dorpat, 1862.

274 THE ALIMENTARY TRACT, ETC.

THE PERITONEUM.

Alltmann, R., Ueber die Veriainderungen des serésen Epithels am blosgelegten
Froschmesenterium. Arch. f. mik. Anat. 1878. Vol. XVI, p. 111.

Arnold, J., Ueber die Durchtrittsstellen der Wanderzellen durch entziindete serése
Haute. Virchow’s Arch. 1878. Vol. LX XIV, p. 245.

Batelli, A., Dello addaltamento di aleune cellule endotiali nelle membrane serose.
Lo Sperimentale. 1884, p. 132.

Cyon, Ueber die Nerven des Peritoneum. Bericht iiber d. Verhandl. d. Kén. Siich.
Gesell. d. Wiss. z. Leipzig, 1868. Vol. XX, p.119. Leipzig, 1869.

Grunau, H., Ueber das Flimmerepithel auf dem Bauchfell des weiblichen Hropches
und ‘bes den Eileiterbau desselben. Dissert. Ké6nigsberg, 1875.

Hoffmann, C, K., Bronn’s Klassen und Ordnungen des Thierreichs. Leipzig und
Heidelberg, 1873-1878. Vol. VI.

Hoffmann, T., Dic Lungen-Lymphgefisse der Rana temporaria. Dissert. Dorpat,
1875.

Kapff, Untersuchungen tiber das Ovarium und dessen Beziehungen zum Peritoneum.
Arch. f. Anat. u. Physiol. 1872, p. 553.

Klein, E., On Remak’s ciliated vesicles and corneous filaments of the peritoneum of
the frog. Quart. Journ. Mic. Sci. New Series, 1872. Vol. XII, p. 43.

Klein, E., On the peripheral distribution of non-medullated nerve-fibres (nerves of
the peritoneum), Quart. Journ. Micros. Sci. 1872. Vol. XII, p. 32.

Leydig, Lehrbuch der Histologie. 1857, p. 325.

Mayer, Ueber die Flimmerbewegung. Froriep’s Notizen, 1836. Vol. XLVII,
Pp: 179.

Neumann, E., Die Beziehungen des Flimmerepithels der Bauchhéhle zum Eileiter-
epithel ikon Frosch. Arch. f. mik. Anat. 1875. Vol. XI, pp. 354-377.

Nicolsky, P., Ueber das Flimmerepithel beim Frosche. Centralbl. f. d. med. Wiss.
1880, p. 641,

- Paladino, G., Dell’ endotelio vibratile nei Mammiferi ed in generale di aleuni dati
sulla fisiologia delle formazioni endoteliche. Estr. dal Giornale intern. delle
Scienze Mediche. 1882. Vol. IV.

Schweigger-Seidel and Dogiel, Ueber die Peritonealhéhle der Frésche. Arbeiten
aus d, physiol. Anstalt zu Leipzig, 1866, p. 68.

Solger, B., Ueber einige Entwicklungsstadien des Peritonealepithels der Amphibien-
larven. Manusce. d. Naturf. Versamml. zu Freiburg. 1884.

Thiry, Ueber das Vorkommen eines Flimmerepitheliums auf dem Bauchfell des
weiblichen Frosches. Gittinger Nachrichten. 1862, pp. 171-174.

Tourneux, Recherches sur |’épithelium des sereuses. Journ. de l’anat. et de la
physiol. 1874.

Waldeyer, Eierstock und Ei. Leipzig, 1870, pp. 72 and 122.

Wolff, W., Ueber freie sensible Nervenendigungen. Arch. f. mik. Anat. 1882. Vol.
XX, pp. 377-381.

I i

THE ALIMENTARY TRACT, ETC.

L THE ALIMENTARY TRACT.

Tue alimentary tract consists of the mouth or pharyngo-oral
cavity, the oesophagus, the stomach, the small intestine and the
large intestine ; these together forming a tube extending from the
mouth to the cloaca. From the commencement of the oesophagus,
at the entrance to the larynx, to the end of the cloaca, the length
of the tube is about 31°5 cm., that of the various parts being :

From glottis to pylorus 5°5 em.
From pylorus to large intestine 22°0 cm.
Large intestine to end of cloaca 4°0 em.

Total length 31°5 cm.

A. The Mouth,
The mucous membrane covermg the tongue will be described
with the sense-organs (see organ of taste).

a. General description. The mouth of R. esculenta, as in all
other amphibia, with the exception of the lowest (Siren, Proteus,
ete.), is of considerable width, and extends backwards as far as
the middle of the tympanic membrane. The upper margin of the
mouth possesses a lip or fold of the skin (SS'), which projects suffi-
ciently to prevent the teeth being seen from the front or from the
sides. This lip-like rim is most prominent in the premaxillary and
superior maxillary regions, but can be traced along the whole length
of the upper jaw, and on to the lower jaw, by means of a well-
marked fold at the angle of the mouth. Beyond this point the lip
is absent, as the skin is closely attached to the bony mandible.

On the roof of the mouth the following structures can be made

T2

276 THE ALIMENTARY TRACT, ETC.

out: immediately within the lip is a deep, well-marked groove, the
outer boundary formed by the lip, the inner by a fold of the mucous
membrane (Fig. 178 /’); this fold increases from behind forwards
as far as the premaxillary bones, where it forms two prominences
(F!, F 1) with an interval between. These correspond to the
palatine processes of the premaxillary bones: immediately behind
‘them are openings of the ducts of the intermaxillary glands.
In the groove so formed are
placed a single row of simple
B'S FF teeth, which, though subject to
pa ‘ many variations, are usually
about fifty in number.

A little further back and to
either side of the median line
is a small group of vomerine
teeth (0) ; each group has from
five to ten teeth; external to
these is on each side a trans-
versely-placed oval opening, the
posterior nares (Cho). These

0 Fig. 178.

The ook ak bie Ganda. apertures are directed outwards
Cho Posterior naris. and backwards into a_ shal-
ID Opening of intermaxillary glands. ; °
F Fold of mucous membrane. low groove, bounded anteriorly
. F', Fl Prominences of mucous membrane.
oe Tena by a fold of mucous mem-
0 Floor of the orbit. brane.
Ss Lip. : . : :
si Lip. According to Wiedersheim the
oT Eustachian tubes. < ‘
Vo Vomer. mucous mnbmbrae immediately
around the vomerine teeth is
supplied with taste-bulbs ; the epithelium. ae ding these being
-“non-ciliated. Ny

The roof of the mouth underneath the paradtiitnoid i is somewhat
vaulted and on either side depressed by the eballs, which project
downwards more or less prominently (0, a si ‘further back
are the openings of the Eustachian tubes (Pig. 178 7)).one on
each side, and almost surrounded by the limbs of the pterygoid
bones.

On the floor of the mouth (Fig. 179) the tongue (7, 7) forms
the most prominent object ; its shape varying according to the’state
of contraction of its muscles. Behind it, in the middle line, is a
transverse groove (+), corresponding to the posterior border of the
hyoid bone, and still further back is the opening to the larynx (JZ),

—— oe a

- eous membrane of both the roof

Set

THE ALIMENTARY TRACT. 277

a longitudinal slit about 3 mm. in length. The mucous mem-
brane to either side of the tongue is only slightly folded, and

a little in front of the angle of the mouth is depressed into onty

4

tm

an aperture (8), opening into the vocal sac. This opening is sur- ™*4

rounded by small radiating folds of mucous membrane, and is oval
in shape.
Towards the oesophagus the mu-

and the floor of the mouth is thrown
into numerous longitudinal folds.

b. The minute structure of the
several parts.

(1) The mucous membrane of
the mouth. At the junction of the
skin and the mucous membrane
there is a gradual transition from
the stratified epithelium of the
skin to a single layer of colum-

nar epithelium. On the floor Pie tic kts iabitha

of the mouth this condition is K Muscles,

reached at the tongue; on the jy yout”

roof the transition takes place § Qpening to volco-ac{in males only)
more quickly, The columnar Z Tongue. 1

epithelium of the mouth (that of { Folds opposite hinder yar
the tongue is excluded from this ge

description) is ciliated ; scattered cells, which are not ciliated, are
found here and there irregularly, but are not numerous. The
cylindrical cells are very finely granular in their upper parts,
clearer in the middle portion, more coarsely and darkly granular in
their deeper portions ; each cell is possessed of a large, well-defined,
oval nucleus, which contains one or sometimes two nucleoli. The

non-ciliated cells usually present a sharply differentiated, structure- -

less, hyaline, free border (Schultze). The epithelium towards the
margin of the mouth, where it is stratified, is also ciliated.

Goblet-cells occur in every part of the epithelium, whether cili-
ated or non-ciliated, and their forms vary very greatly.

[The submucous layer is a fibrous connective-tissue matrix,
very rich in nerves and blood-vessels. The capillaries are arranged
in small, somewhat polygonal meshes (Fig. 180), and are peculiar,
with those of the anterior part of the oesophagus, in having small

278 THE ALIMENTARY TRACT, ETC.

dilatations. This arrangement was first ' described by Langer, and
later by Schébl. The dilatations are placed quite irregularly on the
capillaries, sometimes only on one side, sometimes on both sides of
the vessel ; a slight constriction occurs at the neck of each dilatation,
where it opens into the capillary*. The nerves of the mucous
membrane underneath the orbits have nerve-cells attached to them
(Stirlmg and Macdonald, page 170). The lymphatics are very
numerous, and for the most part follow the course of the blood-
vessels to their finest twigs, beyond which they follow an saa jan
dent course (Langer). |

(2) The teeth are wanting in the lower jaw; on the roof of the
mouth they are found in two situations: as a single row in the
groove within the lip, and a group on each vomer. Each tooth
has the form of an elongated cone, which in the case of the °
jaw-teeth is curved, in that of the vomerine teeth straight. The
teeth are fixed to the jaw so as to project upwards and slightly in-
wards, those at the front of the mouth projecting backwards, and
those on the vomers project backwards. Each tooth has a small,
sharp projection, or secondary crown on its outer surface (Fig. 181),
placed near the mucous membrane. The teeth are fixed to the
bones by means of Crusta petrosa, which is again united to the bones
of the mandible by a matrix of spongy bone, continuous for the
several teeth. Between the tooth and the mucous membrane is a
layer of flattened epithelium (//), which extends more deeply on the
inner side of the tooth than on the outer; the layer is continuous
with the epithelium of the mouth, and is two to three cells in
thickness. Each tooth has fine longitudinal grooves on the basal
part of its outer surface, and consists of two parts, a crown and
a root. The teeth possess large cavities, the wall being thin and
almost of even thickness, except on the inner surface of the basal
portion of the root, where the wall is wanting, and so forms a
large aperture to the root.

The general skeleton of the tooth is formed of dentine, this is
covered on the crown by a layer of enamel, and the Cuticula dentis
on the socket by a layer of Crusta petrosa.

1 Beale, Phil. Trans., 1863, p. 153, shows dilatations in his drawing, but makes no
reference to them in the text.

? The vascular supply of the mucous membrane of the dorsal surface of the mouth
and oesophagus is shown (after Schébl) in Plate II, Fig. 180, I. Arteries red, veins
blue. II. in the same figure represents the dilatations on the capillaries; after
Schobl.

THE ALIMENTARY TRACT. 279

a. The dentine is a homogeneous substance pierced by numerous
tubules (D), which arise at the pulp-cavity and course in a parallel
direction to the surface of the
dentine, where they form a
rich network with irregular,
interglomerular spaces. The
inner surface of the dentine
is rough, through the presence
of numerous small, dark
tubercles.

8. The enamel covers the
dentine on the apical portion
of the tooth. It has tubes
coursing through it, which are
continuous with those of the
dentine, and presents also
circumferential striations (Fig.
181 III).

y. The tooth cuticle (Cuti-

cula dentis) is colourless and I. Transverse section of the premaxillary bone to
: show attachment of the teeth ; after Hertwig.

Fig. 181.

covers the enamel. It is Magnified 22 times. :
highly refra ctive, very trans- Il, Dentine Agr after Hertwig. Magnified

P 500
parent, and very resistant to Il. Enamel: after Hertwig. Magnified soo times
chemical reagents. From the ere ber env ey.

A

C Crusta petrosa.
apex, towards the Crusia BE egret
petrosa, it thins very rapidly, H Layer of epithelium.
but is continued sufficiently Naas scam
far to cover a portion of the 6 maak,

X Cutaneous glands.

Crusta petrosa.
_ 8. The Crusta petrosa resembles bone, except that it contains no
Le Haversian canals ; it possesses cells which resemble bone corpuscles,

and are usually somewhat rounded or oval and communicate with
each other by their processes ; for the most part it is homogeneous
and free from cells (Hertwig).

e. The pulp-cavity contains a connective-tissue very rich in
cellular elements; those cells adjacent to the dentine are arranged
in a layer (Membrana eboris) which has somewhat the appearance of
a layer of epithelium. The cells (odontoblasts) of this layer are

_spindle-shaped, and send processes (dentinal fibres) into the dentinal
tubules. A small blood-vessel can be traced into each ote but
as yet no nerve has been found in the pulp-cavities. =

280 THE ALIMENTARY TRACT, ETC.

[Smith (/. c.) has, after careful investigation, come to the
conclusion that the teeth of 2. esculenta and R. temporaria are
practically alike, therefore the methods of differentiating the two
species by means of the teeth, as given by Leydig, are not to be
relied on. |

(3) The intermaxillary glands (G/andula intermavillaris) consist
of a mass of convoluted tubes, lying chiefly between the pre-
maxillary bones and the capsule of the nose, and opening by about
twenty to twenty-five ducts at the fore-part of the mouth (Fig.
178 ID). A portion of the glands extends high into the nasal
cavity (Born), while dorsally another portion lies under the skin
and the M. dilatator and M. lateralis narium, which together act as
compressors to the subjacent glands: a small, elastic, cartilaginous
rod, placed between the anterior margin of the nasal capsule and
the under surface of the ascending limb of the premaxilla, opposes
these muscles on either side by its spring-like action (Wiedersheim).

In a fresh skull the openings of the ducts can easily be seen
after washing away the mucous secretion ; they are, however, seen
to better advantage by treatment with Miller’s fluid and subsequent
staining with carmine. With sufficient magnifying power, they
are then seen as a row of bright dots. The tubules are of uniform
thickness, placed closely side by side, and surrounded by a nervous
plexus, which contains numerous branching nerve-cells. The epi-
thelium of the tubules is cylindrical, with a rounded, finely granular
nucleus ; processes from the peripheral ends of the cells are con-
tinued to a Membrana propria. The ducts are lined with columnar,
ciliated epithelium.

The secretion of the glands is remarkably adhesive, and is wiped
off by the tongue when it is projected; by this means the tongue
becomes a particularly efficacious instrument for capturing prey.
The glands are, both histologically and chemically, pure mucous
glands. In urodeles the homologous glands are placed in the hollow
septum of the nose,. between the nasal cavities.

(4) The tongue (Figs. 179, 182, 183) is a broad, fleshy flap on
the floor of the mouth, to which it is attached by the anterior half
of its ventral surface as far forwards as the chin. Seen from above
it has a wedge-like form, being narrow in front and wider behind,
where it is prolonged at each angle to form two cornua.

By raising the tongue one obtains a view of a portion of the

“FD

ee

THE ALIMENTARY TRACT. 281

M. hyoglossuz. The two MM. hyoglossi arise (see page 66) some
distance apart, and run forwards and towards each other to meet
on the ventral surface of the hyoid bone ; they now assume a lon-
gitudinal direction, and course forwards parallel to each other until
they reach the M. genio-glossus (Fig. 182 G). Each muscle now
divides to form coarse bundles, which ascend on either side of the
M. genio-glossus towards the dor-
sum of the tongue. In this course
they are encircled by a strong,
elastic, connective-tissue sheath.
The sheath is incomplete at the
hinder end of the MW. genio-glossus,
where it possesses rounded aper-
tures, through which the glosso-
pharyngeal nerves (N, \) disap-
pear, to be distributed, after a
sharp curve backwards, in the
substance of the organ.

The Jf. genio-glossus arises, m
two parts on either side, at the
side of the chm. One part (Fig.
182 G) is dorsal and median, the
other (Fig. 182 G') ventral and
external.

The first part, with its fellow
of the opposite side, forms an
arched commissure in the form of
muscular rings, which decrease in -*% = S="Pharmenal nerve.
size from before backwards, and so form a pear-shaped mass: the

Fig. 182.

weO ERAS
;

second, external portion, extends backwards, with a slight obliquity, ©

as a thin, fan-like expansion, to the mucous membrane, where it is
inserted. This arrangement can easily be seen after dissecting
away the sheath (Fig. 183 Hy); the hindermost fibres curve sharply
into the tongue (Hy"); the anterior fibres pass obliquely forwards
and blend with the straight fibres of the dorsal portion of the
A. genio-glossus (Fig. 183 Gg). The arcuate fibres.of the M. genio-
glossus pass, for the most part, upwards and outwards to the tips of
the posterior bifid border of the tongue; in this course they lie as
a rule above the MW. Ayoglossuz, but here and there the two muscles

intermix (Fig. 183 Gg"), and it is by no means easy to separate _

them.

Ares.

282 THE ALIMENTARY TRACT, ETC.

Fig. 183. The I. hyoglossus is the retractor

G of the tongue, the I. genio-glossus
| the protractor.

(For mucous membrane of the
tongue, see organ of taste. The
vocal sacs are described with the
organs of voice and respiration.)

B. The Oesophagus and Stomach
(Figs. 184, 185, 189, 194, 195,
199). ,

a. General description. The
oesophagus is not separated from the
pharyngo-oral cavity by a sharp line
of demarcation. It has a length of

Muscles of the tongue, from the ventral

surface, only a few mm. in medium-sized
G M. genio-glossus, : ° 3
Gg Straight fibres of the M. genio-glossts, frogs (Fig. 184 Oc), and les in the

Gg Curved fibres of the M.genio-glossus. middle line of the body, supported
< Rani ete on either side by the cornua of the

hyoid bone. The oesophagus lies on
the dorsal wall of the larynx, is smooth externally, and is thrown
into well-marked longitudinal folds internally.

The transition from oesophagus to stomach is somewhat indefi-
nitely marked by a slight dilatation of the tube, often scarcely per-
ceptible, still it can always be recognized by an abrupt curvature to
the left (Fig. 184 1), which becomes more prominent when the
stomach is distended. Externally the stomach is seen as an elon-
gated, slightly curved cone, smooth externally and of equal diameter
throughout. eth

The oesophagus and stomach are held in position by folds of
peritoneum (mesentery), which attaches them to the dorsal wall of
the abdominal cavity, to the lungs, pericardium, and liver; and by
the blood-vessels.

b. Minute structure. The walls of these viscera are composed
of four layers or coats. m4

(1) The serous coat (Fig. 186) is " layer of endothelium, lying
on a very thin stratum of connective-tissue; the whole derived
from the peritoneum, which encloses the organs.

(2) The muscular coat (Fig. 186 LM and 7M) is arranged in

———E——

See ee

a

THE ALIMENTARY TRACT. 283

two. layers, one (LJ) longitu- Fig: 184.
dinal, the other (7) trans- ; ?
verse. The longitudinal layer
is thicker in the oesophagus,
and thins as it is continued to
the pyloric end of the stomach.
The circular layer, on the other
hand, gains in thickness ; both
layers are of unstriated mus-
cular fibre.

—M

(3) The submucous coat
(Fig. 186 4, B, and SM) is
better developed in the stomach |:
than in any other part of the
alimentary canal. Itis formed
of a wide-meshed, loose con-
nective-tissue, which supports
numerous blood-vessels and
lymphatics. Towards the
mucous coat it possesses a
well-differentiated Muscularis
mucosa, Which is arranged in
two layers, a longitudinal (2)
‘and a transverse (4).

(4) The mucous coat is pos-
sessed of numerous tubular
glands, which vary in structure
according to the. part of the
membrane examined. They
have been the subject of much
investigation (Heidenham, ©
Nussbaum, Partsch, Langley, Du Duodenum. .
and others), and are best de- A oe

scribed in three groups: those ¥* Spleen.

of the oesophagus, of the first Py —

part-of the stomach, and of { Sumtion of small and lage intestine
the pyloric end of the stomach respectively ; between each pair of
groups are transitional forms.

a. [The oesophageal glands are complete tubular glands lined
by a single layer of epithelium, which very closely resemble the

The alimentary canal.

Opening of large intestine into cloaca.
Cloaca.

284 THE ALIMENTARY TRACT, ETC.

glandular cells of the fundus of the stomach (Plate II, Fig. 187).
The cells are conical or cylindrical, the protoplasmic contents

Fig. 185.
a | ; i

: . ; tics

’

The abdominal viscera of Rana esculenta (female).

D Small intestine. Tl ~ Right lobe of liver.
Du Duodenum. L2 Middle lobe of liver.
EE Ovaries. Ig Left lung.
H = Heart. ig Right lung.

. HB Urinary bladder. M = Stomach,

L Left lobe of liver,

granular, the granules being larger than those of the corresponding
cells in the stomach (Langley). Mucous cells are found among
the true secretory cells. The cells of the ducts are sometimes,

but rarely, ciliated (Langley). ]

\

THE ALIMENTARY TRACT. - 285

8. [The glands of the fundus of the stomach’ are not so complex
as the typical glands of the oesophagus. The cells at the mouth
of the gland are continued
into fine processes (Fig. 187),
and their. outer parts contain
mucigen. The cells of the
neck of the gland are more
eubieal, and towards the
lower part of the neck are
mucous cells. The cells of
the body of the gland are of
irregular shape, and so placed
that the nucleus of one cell
faces the junction of two
cells on the opposite side
(Langley). These cells are
very finely granular. ]

Fig. 186.

wT Ox

y- [The glands of the py-
loric end of the stomach have
been compared with the
mouths and necks of the
glands of the fundus (Partsch,
Langley). The cells are of
two kinds only (Fig. 188).
The cylindrical cells of the
‘surface of the stomach are "2°" nee ponent fee 5 9
continued into the gland, — general arrangementof the walls —G. H.
where they becom: e shorter A Transverse layer of muscularis mucosae.

i 5 B Longitudinal layer of muscularis mucosae,
and sub-cubical; these form £4 Longitudinal muscular coat.

the greater part of the Sai. Balewainn ek.
samt The. elie cw: the
deepest portion of the gland are more rounded, and resemble the
mucous cells in the neck of the glands of the fundus. |

&. [Between these well-marked groups of glands are various
transitional forms. The transition from oesophageal to gastric
glands is not a continuous one, as glands resembling those of the
stomach can be found nearer the oesophagus than other glands, which

‘ A transverse section through the mucous membrane of the fundus of the stomach
of Rana esculenta is shown in Plate II, Fig. 187. Alcohol preparation, doubly
stained with carmine and anilin blue. After Biedermann. (Obj. II, Syst. 7,
Hartnack.)

286 THE ALIMENTARY TRACT, ETC.

more nearly resemble oesophageal glands. At the same point the
mucous membrane is thinner than either in front or behind. In
the same way an intermediate zone exists
between the typical glands of the fundus
and pylorus of the stomach. |

In both oesophagus and stomach the
mucous membrane is thrown into longi-
tudinal folds when the organs are empty.
The epithelium of the surface of the
oesophagus is mostly ciliated, and possesses
numerous goblet cells; according to Klein
the cells are not set vertically on the sub-
jacent submucosa, but obliquely.

[The epithelium of the surface of the
: stomach is, at least in part, ciliated (Re-
Transverse section through the géczy, Trinkler, and others), and has nu-

mucous membra f th ; ;
pylorie end of the stomach merous goblet-ceils (Schultze, Heidenhain,

aarp, ( neue ee Bleyer, Eimer, Oedmonson, and others). |

Hartnesk} (5) [The nerves of these organs, accord-
ing to Gonjaew, contain both medullated and non-medullated fibres,
which have nerve-cells attached to them. From these fine branches
pass, either with the blood-vessels or alone, to the mucous coat,
losing their medulla on the way. In this course they inosculate
very freely, and are then distributed as very fine, beaded fibrils to
the glands and epithelium, which are very richly supplied. |

(6) ['The blood-vessels and lymphatics very closely resemble the
corresponding: structures in the small intestine (p. 290); the blood-
vessels form a rich anastomosis in the submucous membrane; the
lymphatics are arranged in two systems, one under the serous coat,
and a larger system in the mucous and submucous coats. The
oesophagus lies free in a peri-oesophageal lymph-sac (Robinson). |

C. The Small Intestine.

a. General description. The small intestine commences behind
the middle of the abdomen at the pyloric end of the stomach, from
which it is marked off by a slight constriction. The first portion
of the small intestine is the duodenum (Figs. 184 and 194 Du); by
means of an abrupt turn it winds directly forwards, parallel to the
long axis of the stomach ; the pancreas is placed in the loop so
formed.

The whole of this. portion of the intestine, together with the

THE ALIMENTARY TRACT. 287

greater part of the stomach, is, in the normal condition, under cover
of the liver (Figs. 185, 194): while under the liver the intestine
is firmly attached to the deep surface of that organ by a short
but strong Ligamentum hepato-duodenale; it then turns suddenly
backwards, increases in size, and by means of numerous convo-
lutions occupies a considerable portion of the right half of the
abdomen (Fig. 184 D). It is held in position by a well-developed
mesentery.

b. Minute structure. Like other portions of the alimentary
canal, the small intestine is formed of four layers :—

(1) The serous coat presents no peculiarities ; it consists simply

of a layer of endothelial cells, with a small amount = sub-endothe-
lial connective-tissue.

(2) The muscular coat is in two layers, the outer longitudinal
layer being very thin, the inner circular layer thick.

(3) The submucous layer resembles that of the stomach, but is
not so thick ; the muscu/aris mucosae is well developed and arranged,
as in the stomach, in two layers.

(4) The mucous coat (Fig. 189) is thrown into folds, which differ
in various parts of the tube.

The longitudinal folds of the stomach are compressed together
towards the pyloric end of the stomach (a) and diminish in size; at
the commencement of the duodenum they end abruptly (a'), but
without any indication of a valvular arrangement.

Immediately beyond the pylorus the mucous membrane is folded
so as to form an irregular network of folds which inclosé irregular
alveoli; the folds are thicker on the concave surface of the duo- —
denum, and form a longitudinal ridge (4); mm this ridge the
alveolar spaces are much smaller than those to either side. The
- irregular folding extends through two to three cm., when a more
regular arrangement commences in the form of two adjacent series
of transverse folds (¢, c!). Each fold is semi-lunar in shape, with
the convexity attached to the wall of the tube and directed forwards,
while the concave free border and pocket-like space enclosed are
directed backwards.

The arrangement of these folds reminds one of the semi-lunar
valves of. the human heart, and probably one of their functions is
to prevent the regurgitation of the chyme (Wiedersheim).

The correspondmg valves of opposite sides meet at each end at
an angle, the apex of which is directed away from the stomach. On

THE ALIMENTARY TRACT, ETC.

these folds and between them are smaller,
secondary folds, partly irregularly arranged,
partly longitudinal (d @).

Towards the middle of the small intestine
this valvular arrangement is lost, to be replaced
by an irregular net-like folding; beyond this
longitudinal folds arise, which proceed in a’
sinuous course towards the large intestine.

The whole mucous membrane, both on the
folds and otherwise, is covered with a simple
layer of columnar epithelium, which is con-
tinued into numerous simple follicles (glands
of Lieberkiihn) found throughout the mucous
membrane of the small intestine. The cells
are placed on a basement membrane, which
rests on a thin layer of loose connective-tissue,
intervening between the epithelial coat and

Mucous membrane of the
pyloric end of the stomach
and the duodenum.

a Mucous membrane of

a! Commencement of the muscularis mucosae. The epithelial cells .
bent. cons are intermixed with a large number of goblet-
ee ee cells, and have between them fine processes
work, from the connective-tissue corpuscles of the

¢ ) Semi-lunar folds of the

cl § » mucous membrane.

ad Longitudinal folds of
the mucous mem-
brane.

subjacent layer; many of these processes
extend to or even beyond the free margin of
the epithelial cells.

The individual cells are columnar, possessed.
of a well-marked cell-wall, and have distinct, large, oval nuclei,
containing one or more nucleoli. The protoplasmic contents are
' granular, and with proper treatment show a very distinct intra-
cellular network. The free margins of the cells are sharply marked
off from the cell-contents, and are more firmly attached to the cor-
responding portions of adjacent cells than the rest of the cell-wall.
This margin has a longitudinal striation, which owing to the im-
portant function performed by this part of the intestine, namely,
absorption of the fat, has been the subject of many important
investigations.

[In the following brief summary of the earlier researches on the minute structure
of the intestinal epithelium, in which the intestine of the frog was chiefly used, the
memoirs in which these investigations are recorded are referred to in the order of
time.

1837. Henle first described the border as a thickened, highly refractive portion
of the cell-wall.

1855. Kélliker and Funke, after independent research, described the longitudinal

THE ALIMENTARY TRACT. 289

Striation : Funke offered no explanation of the fact, while Kélliker considered it due to
the presence of fine tubules. Later Funke gave a modified support to Kélliker’s view
by admitting the presence of tubules around the circumferential part of the border.

1856. Donders gave a description corresponding with that of Henle.

1857. Brettauer and Ste’nach gave it as the result of their investigations that the
border was composed of closely-applied fine rods: v. Wittich first showed that the
borders of adjacent cells were more firmly attached than the rest of the cell; he
admitted the presence of apertures, but considered the whole appearance to be due
to post-mortem changes.

Welcker and Friedreich agreed with the views of Brettauer and Steinzch, but

_ traced the striation throughout the length of the cells, in fact traced the tubules to
the connective-tissue below,

1858. In this year Heidenhain published his results; he held the striation to be
due to the prgsence of fine rods, and was the first to show that processes of the con-
nective-tissue corpuscles passed up between the epithelial cells; he found fat globules
in the epithelial cells, in the connective-tissue, and in the lacteals.

Friedreich described the striation as continued through the whole length of the
cells, and as due to tubules.

1859. Lambl denied the presence of the rods, and considered the whole phenomenon
an optical appearance due to the cell-wall ; in this view he was supported by Vlako-
vich of Padua and Amici of Florence.

1860. Wiegandt held the border to be an independent covering, and the striation
to be due to folding or wrinkling.

Col. Balogh described the border as formed of rods, but denied that these existed
except when brought about by the action of fats; in support of this view he showed

“that the striation was wanting when fat was absent. -

1865. Lipsky held the border to be composed of rods.

1866. Henle described the cells as in his former work, but now held the border
to be composed of rods, in fact to represent a ciliated border.

1867. Erdmann described the border as being of two layers, an upper, thicker
layer, with both longitudinal and transverse striation, and a lower, thinner layer,
the true cell-wall. The upper layer he described as capable of splitting in the di-
rections of both striations.

Schultze described the border as not being in intimate connection with the proto-
plasm of the cell. Arnstein and Wiegandt supported Heidenhain’s description.

1868. Albini e Renzoni described the part as resembling resting cilia.

1869. Eimer traced fat-globules into all the parts, epithelium, connective-tissue, and
vessels ; and held that the fat could pass from a lacteal to a branch of the Vena porta.

1870. Heidenhain, after further investigation, supported his earlier views.

1874. Thanhoffer described the membrane as perforated, and the protoplasm of the
cells as actively sending protoplasmic processes through these apertures ; this he had
seen in frogs in which all connection with the spinal nerves had been severed.

1875. Benjamins could not find the striation to be a constant occurrence, and failed
to find the processes described by Thanhoffer.

1876. Krause found rod-like bodies round the margin of the border.

1877. Fortunatow supported Thanoffer’s view.

1881. Landois observed appearances in Spelerpes fuscus, which led him to sup-
port Thanoffer’s views, ;

1883. Wiedersheim supported Thanhoffer’s views.

1884. Wiemer supported Thanhoffer’s observations.

1888. Paneth failed to find any contractile protoplasmic processes, and asserts that
the circumference of the border, when examined under certain conditions, is com-

posed of rods.

From the same causes the goblet- or chalice-cells, already mentioned, have been
the subject of much speculation and investigation.

1846. Frerichs drew and described these cells as empty cells.

In 1848 these cells were first described as epithelium capitatum by Gruby and
Delafond.

U

290 THE ALIMENTARY TRACT, ETC.

In 1856 Donders described the cells as being open, and as discharging their contents
into the canal; the cell-walls being then pressed together by the neighbouring cells,
and the cell-contents being then gradually reformed. ;

In the same year Kolliker published results closely agreeing with those of Donders,
and he traced the various stages of the process.

1857. Brettauer and Steinach held them to be cells which had lost their contents,
and as the ‘cuticular border’ was absent, concluded that the cell-contents were in
closer connection with the ‘ border’ than with the rest of the cell-wall.

1865. Lipsky and Sachs both doubted the presence of such cells, and considered
them due to the action of reagents or post-mortem change.

1866. Letzerich described the cells as open, and regarded them as the commencement
of the lacteal system, while Dénitz thought the whole appearance due to reagents.

1867. Schultze and Eimer, independently, described them as unicellular glands.
Erdmann, however, again denied their occurrence under normal conditions.

Oeffinger held the goblet-cells to be modified ordinary cylindrical epithelium cells ;
in which view he was supported by Arnstein.

1868. Schultze and Eimer, after renewed investigations, reiterated their former
opinions,

1869. Eimer described the goblet-cells as secreting mucin, and as capable, by
division, of throwing out pus-like cells.

1876. Krause described the cells as containing granular contents, which under
certain conditions are thrown out.

1877. Tolldt considered them artificial productions, Edinger asserted that they are
formed from the cylindrical cells.

1877-1885. Partsch (1877), Klein and Hebold (1879), Stohr (1880), Patzelt (1882),
Haller (1883), Holl (1885), support the last view.

1878. Hoffmann supported Schultze’s views.

1886. List describes these organs as unicellular mucous glands.

1887. Paneth described them as secreting mucous and as being derived from the
cylindrical cells.]

(5) [The blood-vessels of the small intestine (p. 234) have been
described by Langer ; he finds the vessels arranged in networks,
one a subserous network, placed underneath the serous coat, and
formed of elongated, irregular, four-cornered meshes. When the
intestine is distended the meshes are rectangular.

The vessels to the mucous membrane divide and anastomose very
freely in the submucous layer, and then form an irregular network
on the inner surface of the Muscularis mucosa’; this network follows
all the foldings of the mucous membrane, and thereby supplies a
double layer to each villous fold of the mucous membrane. The
meshes are usually four-sided or five-sided. |

(6) [The lymphatics of the small intestine (Figs. 190, 191). The
lymphatic vessels on reaching the intestine usually bifurcate ; the
two branches, as a rule, follow and enclose an arterial twig. From
the serous layer they receive the contents of a very fine lymphatie
plexus, the lumens of which are slightly greater than that of the
corresponding’ capillaries ; from the mucous layer they receive the
contents of the lacteals: between these two layers the lymphatics
anastomose very freely by means of numerous branches (Langer).

The lacteals are lined with an epithelioid layer and traversed by
connective-tissue trabeculae, which have a like covering. The

THE ALIMENTARY TRACT. 291

lacteals are not simple but in the form of a coarse network (Fig.
189), (Langer).]

(7) [The nerves of the
small intestine (p. 200) usu-
ally follow the arteries to
the muscular coats, between
which they form a plexus

_ (Auerbach’s plexus); from

‘this numerous twigs are
given off, which course alone
or in company with vessels
to the mucous coat, Where [Isolated fold of mucous membrane of small intestine
a second plexus (Meissner’s tune tmrrir ater Tang. "Ft tie
plexus) is formed. Auerbach’s
plexus, according to Klein, consists of bands of nervous fibrils in
endothelial sheaths ; they branch and inosculate, and thus form a
plexus. Where several such branches
meet, a more or less complicated decus-
sation of the bands of fibres takes place.
Along these nervous bands are ganglion
cells, either isolated or in groups. The
cells are large, generally spherical, and
contain a sharply outlined nucleus with
a single or double nucleolus. The
smaller cells generally appear to possess
only one process, which can be traced
from the protoplasm of the cell between
the fibrils of the nerve-trunk. The
larger cells are distinctly multipolar,
their protoplasm being provided with a
number of fine processes, or, as is
oftener the case, with one large and
several small processes. In many in-
stances Klein was able to distinguish
around the ganglion-cells a capsule of
a spherical or ovoid shape. Im these transverse section of a fold of the
eases the body, as well as the processes PUSS IanTumene| ‘winty thes
of the ganglion-cell, were lying within natural size.
the capsule. This system of ganglion- 4 ee Se, See
cells is in connection with the individual 8° Cirenlar muscular layer.
bundles within the nerve-trunks. geet gai ae sks

U2

292 THE ALIMENTARY TRACT, ETC

Klein describes a second system of ganglion-cells, situated in
meshes, which are formed by the nerve-trunks of the plexus itself.
These ganglion-cells are much larger than the former, and are
multipolar ; their protoplasm, which is distinctly fibrillar, with
granules between the fibrils, is provided with one or two long, thick
processes and several short and thin ones; generally the processes
are branched. The general shape of the cells is oblong, the thick,
long processes being commonly at the two opposite poles. The
cells are generally isolated, sometimes situated in the centre of a
mesh, or more commonly near a nerve-trunk that borders the mesh
on one side. Each ganglion-cell
is connected with a nerve-trunk
of the plexus by at least one
process. In a few of the nerve-
trunks of the general plexus, iso-
lated medullated nerve-fibrils are
seen to pursue an almost straight
course from one trunk into
another and divide imto two.
There is no connection between
these medullated fibres and the
ganglion-cells.

Fig. 192.

Auerbach’s plexus is a much
finer plexus than that just de-
scribed, and the ganglia are much
smaller. It supplies twigs to
the Muscularis mucosa; these break
up into fine fibrils, which follow
the direction of the muscle-fibres ;
other twigs supply the blood-
vessels, with which they can be
From a transverse section of the large intestine traced into the bases of the folds

of Rana temporaria, moderately distended. of mucous membrane. Thanhoffer

—G. H. :
has recently (/. ¢.) described nerve-
A Denser portion of submucous coat. fibrils, which terminate in the
B_ Looser portion of submucous coat. R .
C Artery, cut obliquely. mucous epithelium. |
DP Circular muscle-layer.
E Longitudinal muscle-layer. D Th e Lar ge Intestine io
. ( I gc.

184 R).
a. General description. The large intestine is a flask-shaped
-viscus, lying in the median line. The small intestine opens into it

ll

THE ALIMENTARY TRACT. 293-

by an abrupt curve at its anterior end. The large intestine is the
' widest part of the alimentary canal, is thin-walled, and diminishes
in width towards its hinder end, where it opens into the cloaca
above the opening of the bladder.

b. [Minute structure.
(1) The serous coat resembles that of the small intestine, ete.

(2) The muscular coats resemble those of the small intestine, but
are thinner; the longitudinal layer is, however, proportionally
thicker (Wiedersheim).

(3) The submucous coat (Fig. 192) resembles that of the small
intestine in its general structure; the portion lying immediately
beneath the mucous membrane (#) is denser in structure.

This layer has no Muscularizs mucosa.

(4) The mucous coat (4) is a simple layer of large, columnar,
epithelial cells, with large oval nuclei. The cells have a hyaline
free border, but this possesses no stri-
ation. The mucous membrane is usually
described as possessing’ numerous simple
follicles (glands of Lieberkiihn) ;
those specimens which I have exa-
mined they have been entirely absent
(Figs. 192, 193). At six to eight
points in a transverse section of a
rectum moderately distended the sub-
mucous coat is thinner, and so throws the
mucous coat into slight, longitudinal
grooves; but these do not in the least
resemble the glands of Lieberkiihn.

_ (5) The epithelium possesses goblet-
or chalice-cells (Hoffmann), the number

of which probably depends upon poe) oe oe a
the period of the year and the state ‘Kana esculenta; the mucous mem.

° ° brane thrown into longitudinal folds
of digestion. In the rectum, from 3 sunaienins cb ths caain botnx

which the section for the figures 192 Berne Arteria Aajocted: with

and 193 were cut, not one goblet-cell 4 Large circular vewels within the
was found in a complete series of , PUMA cats he mucous
sections. coat.

If the rectum be contracted, the mucous membrane is thrown into

longitudinal folds,

Fig. 193.

294 THE ALIMENTARY TRACT, BTC.

(6) The blood-vessels (Fig. 193) have a simple arrangement.
The arteries are large, and form oblique loops around the intestine,
lying under the peritoneum ; from these branches are given off to
form a series of rings in the submucous membrane (Fig. 193 A) ;
from these fine twigs are given off to form a fine anastomosis under
the mucous membrane (JS).

(7) The lymphatics of the large intestine are arranged in two
chief systems : one under the serous coat resembles the corresponding
system of the small intestine. The second set forms a network of
rounded loops in the submucous coat, which give rise to a secondary
set of smaller vessels towards the mucous membrane ; this secondary
system forms a sort of trellis-work standing on the rounded loops,
and so maps out small blocks of the thick submucous coat. Towards
the cloaca the arrangement is simpler; the secondary lymphatics
are lost, while the primary Pphene tend to form elongated,
longitudinal loops (Langer). |

\

Il. THE GLANDS CONNECTED WITH THE
INTESTINAL CANAL.

A. The Liver and Gall-bladder,
a. External form,

(1) The liver (Figs. 185, 194) is a large, reddish-brown organ,
occupying a large part of the anterior abdominal region. It con-
sists of three or more lobes, which present many individual varia-
tions; as a rule there are two larger lateral lobes (/ and J"), and
a smaller median lobe (Z*). Each lobe has a superficial or ventral
surface, which is convex, and a deep or dorsal surface, which is con-
cave and directed towards the other abdominal viscera lying above
the liver. The two surfaces of each lobe meet to form a sharp
border around the lobe, except where the three lobes are more
intimately attached, opposite the apex of the heart (Figs. 185,
194); at this place each lobe possesses a small, flat, or slightly
concave anterior surface,

The left lobe (Z) hides the greater portion of the stomach, and .
has near its inner border a deep fissure, which runs forwards and

GLANDS CONNECTED WITH THE INTESTINAL CANAL. 295

so marks off a more or less well-marked fourth lobe. The
anterior portion of the left lobe is attached to the corresponding
portion of the right lobe by a narrow commissure.
The median lobe (Z*) ex- Bis igi,

- tends backwards as far as the Siete

EN
pylorus, and covers the com- Z he
mencement of the intestine <
together with the pancreas ;
these organs can, therefore,
not be seen until this lobe
is displaced. A fifth lobe is
sometimes found on the dorsal
surface of the median lobe,
and to it or to the dorsal sur-
face of the median lobe the
small intestine is attached by
the Ligamentum hepato-duode-
nale (Fig. 195 Lhp). The
Vena portarum enters the liver

. - 4: The liver, seen from the ventral surface.
behind this ligament. ae shan
The right lobe extends much H Heart.
L Left lobe of liver.
further dorsalwards than the Ll ~ Right lobe of liver.
7 L2 Middle lobe of liver.
left lobe, and even comes in pylons

contact with the lung, the
vessels of which sometimes indent its surface in spirit specimens.
This lobe is also in contact with the base of the fat-body, and in
females with the oviduct.

By drawing the lobes of the liver to either side and displacing
the heart towards the head, the posterior caval vein is seen passing
from the liver to the heart, and the hepatic commissure joining the
lateral lobes is brought into view.

- A

(2) The gall-bladder (Fig. 195 @) is placed on the dorsal surface
of the liver in the deep niche between the right and left lobes ; it
is attached to the liver by connective-tissue and peritoneum.

The gall-bladder is round or oval in form ; when moderately full
it has a smooth, outer wall, which is thin and allows the green colour
of the bile to be seen. It possesses a duct (Dey), the cystic duct
(Ductus cysticus), which bifureates near its origin.

The two cystie ducts (Fig. 195 Dey) join the larger hepatic
ducts, as shown in the figure, and so form a simple anas-

296

THE

ALIMENTARY TRACT, ETC.

tomosis, from which three branches (3) of varying size unite at the
anterior extremity ef the pancreas to form the common bile-duct

The pancreas and bile-canals.

De
Del
De2
Dey
Dh
Dhi

Du
G
L
Ll
[2
L3
Lhp
M
P.
Py
Pl

Fig. 195.
1”

i
Py
The liver has been displaced
towards the head.

Common bile-duct.

Common bile-duct after leaving the pancreas.

Opening of the common bile-duct into the duodenum,

Cystic ducts.

Hepatic ducts.

Supplementary hepatic ducts from the middle lobe of
the liver.

Duodenum.

Gall-bladder.

Left lobe of the liver.

Right lobe of the liver.

Middle lobe of the liver,

Fourth lobe of the liver.

Gastro-hepatic ligament.

Stomach.

Pancreas.

Pylorus.

Ducts of the pancreas.

(Ductus choledochus, De).
The common bile-duct
runs through the whole
length of the pancreas,
receiving near its origin
additional hepatic ducts
(Di) from the middle
lobe of the liver. . In
this course the duct lies
either on the ventral
surface of the pancreas
or under a thin layer of
the glandular tissue ; it
receives the ducts of the
pancreas and leaves that
organ at its posterior
border as a round and
strong canal (Dc'). The
duct courses in the
gastro - duodenal _ liga-
ment, and reaches the
dorsal surface of the
duodenum at a very
acute angle; it then
pierces the wall ob-
liquely and terminates
with a slit-like or elon-
gated oval opening.

b. [Minute structure.

(1) The liver is com-
posed of various tissues :
it possesses a peritoneal
covering’, a fibrous cover-

e, which supplies tra-
beculae to support the

various other tissues, blood-vessels, hepatic cells or true liver paren-
chyma, and bile-canals.

a. The peritoneal covering of the liver encloses the organ
almost completely, the only exceptions being where the various

GLANDS CONNECTED WITH THE INTESTINAL CANAL. 297

attachments of the liver are found (see peritoneum). The perito-
neal covering of the liver is for the most part composed of flattened,
ciliated cells (Neumann and Grunau); on the middle lobe these are,
however, more or less replaced by non-ciliated cells. The thickness
of these cells varies considerably, according to the amount of dis-
tension to which the liver is subjected.

8. The fibrous covering of the liver is very thin and very diffi-
cult to demonstrate ; it consists of connective-tissue fibres with very
few corpuscles, This covering is prolonged into the liver along the
portal canals, where traces of connective-tissue can always be
made out.

From these processes and from the whole of the inner surface of
the general connective-tissue capsule are given off fine trabeculae,
in which it is very difficult to find any nuclei; these trabeculae
are everywhere extremely delicate and difficult to demonstrate ;
nowhere do they form distinct boundaries between lobuli: the
structure closely resembles the sustentacular tissue of a lymphatic
gland (Eberth).

y- The blood-vessels to the liver are the “nesta vessels (p.
249), the hepatic veins (p. 247), and the hepatic artery’ (p.
233).

(1) The portal vessels pass into the liver on its ventral surface ;
they divide into branches which course along the middle parts of
each lobe and give eff smaller branches in all directions towards the
periphery ; the interlobular branches (Fig. 196 1) forming a very
complex capillary network. compared with the hepatic veins
(Fig. 196 II), the interlobular veins do not give off their capillaries
so abruptly, but tend to supply these from small lateral branches.
The portal veins are accompanied in their course by branches of the
hepatic artery, and often by larger bile-ducts, and thus form
portal canals. In no part do the portal (interlobular) veins or their
branches limit the lobules by distinct rings of vessels, as seen In
many higher animals. The interlobular veins —_ intralobular veins
simply interdigitate with each other.

1 See Plate II, Fig. 196.

1. Partial injection of the liver from the portal vein (blue): Rana esculenta.—G. H.
If. Partial injection of the liver from the hepatic vein (red): Rana esculenta.—G. H.
Yil. Complete injection of the liver from the hepatic artery (red) and from the portal vein
(blue): Rana esculenta.—G. H. -
A Portal (interlobular) veins and their branches.
B Hepatic (intralobular) veins and their branches,
C Hepatic arteries and their branches,

298 THE ALIMENTARY CANAL, ETC.

(2) The hepatic veins (Fig. 196 I and II) also course chiefly in
the middle parts of the lobes of the liver; they branch, and ulti-
mately supply intralobular ves which interdigitate with the inter-
lobular veins (I and II). The capillaries arise very abruptly from
an intralobular vein, and form a network of vessels communicating
very freely with the corresponding capillaries of the interlobular
veins.

(3) The hepatic arteries (Fig. 196 III) break up into small
branches which, as a rule, course along the portal canal until near
the surface of the liver, when they leave the portal veins and pass

.to the surface to supply the coverings of the liver. In their course
along the portal canals they supply a few very small twigs to
the structures forming the canals. At the surface of the liver
the branches of the hepatic artery form capillaries, which empty
themselves into the general capillary anastomosis beneath (Fig.

196 III).

6. The liver-cells (Figs. 197, 198) are large, and of compressed
spheroidal or polygonal shape. They possess no cell-wall, have
usually one but sometimes two large nuclei, each with a distinct
nucleolus. The cells often contain granules of glycogen or fat-
globules. The main fibrillae of the intercellular network are
arranged so as to extend between a bile-capillary and a blood-
capillary (Fig. 197).

e. The bile-ducts (Fig. 198) commence as fine tubes between the.
liver-cells, where they are simply small spaces enclosed by the
hepatic cells; they are usually enclosed by three or four cells,
possibly sometimes by only two cells (Hering). Such bile-capillaries
are usually separated from a blood-capillary by the thickness of one
liver-cell only (Fig. 198).

As a number of such bile-capillaries run together to form a larger
duct, the cells enclosing them change their character, becoming
flattened and broader; these cells may, however, be traced contin-
uously into the true hepatic cells (Hering and Eberth). The bile-
duct so formed then obtains a slight covering of fibrous tissue,
which rapidly increases in quantity, courses along a portal canal,
and receives other ducts on the way; the epithelium lining it
gradually becomes more elongated, and ultimately resembles that
found in the common bile-duct or the gall-bladder.

In the larger ducts the epithelium is, according to v. Brunn,

GLANDS CONNECTED WITH THE INTESTINAL CANAL. 299

ciliated ; they also possess a layer of unstriated muscle-fibre
(Eberth).

¢ The pigment of
the liver varies very
much in amount and
character, according
to the time of the
year and state of
health of the animal.
According to Eberth ©
thepigmentary masses
are of about the same
sizeas the white blood-
corpuscles, andare pos-
sessed of the power of
amoeboid movement
(in young animals).
The cells possess two
to seven nuclei and vary much in colour and distribution. As
a rule the larger the amount of pigment in a given liver the

Fig. 197.

Liver-cells, after Kupffer.

The bile-capillaries ; natural injection with sulphindigotate of sodium: v vv represent
blood-capillaries.—G. H.

smaller is the number of fat-globules found in the individual
liver-cells (Eberth).]

(2) [The gall-bladder and bile-ducts. The gall-bladder has four
coverings.

300 THE ALIMENTARY TRACT, BTC.

a. A serous coat of peritoneal endothelium.

8. A muscular coat, containing unstriated muscle-fibres and con-
nective-tissue.

y. A sub-mucous coat of areolar-tissue. .
6. An internal lining
Hig. #99: of columnar epithelium.

«. The walls of the
gall-bladder are richly
supplied with blood-ves-
sels from the cystic ar-
teries (p. 233); these
form a close network m
the submucous coat.

¢ The muscular and
submucous coats also
possess a rich nervous
plexus, which contains
ganglia and resembles
Auerbach’s plexus of the
intestine (Popoff, Ger-
lach). |

B. The Pancreas (Fig.
199 P).

a. General descrip-
tion. The pancreas is
a flattened, light yel-

The pancreas and bile-canals. The liver has been displaced lowish - brown organ,

ree ae eee placed in the loop of the

De Common bile-duct,
Del Common bile-duct after leaving the pancreas. duodenum between this
De2 Opening of the common bile-duct into the duodenum. latter d th t h
Fee Grats dicks. atter an e stomach.
Dh Hepatic ducts. oan ] ithj
Dhl Supplementary hepatic ducts from the middle lobe of The whole it esky within

the liver. the gastro-duodenal liga-
Du Duodenum. } :
G Gall-biadder, ment, and is attached to
L Left lobe of the liver. j iy j j
Ll Right lobe of the liver. the liver =f hence it is
12 Middle lobe of the liver. little imfluenced by
[3 Fourth lobe of the liver. h : th t
Lhp Gastro-hepatic ligament. changes m € amoun
he 4 of distension of the
Pl Ducts of the pancreas. stomach or intestine.
Py Pylorus,

The organ may be
completely exposed by either of two methods: in the former, the
liver, stomach, and duodenum are drawn towards the head and

GLANDS CONNECTED WITH THE INTESTINAL CANAL. 301

the dorsal surface of the organ so exposed. In the second method
the liver is drawn backwards, the various peritoneal folds which
connect the duodenum with the posterior border of the liver cut
through, and the three organs then separated; the pancreas can
then be conveniently examined.

The size and shape of the pancreas are subject to great variations
in different specimens, The usual shape of the organ is somewhat
triangular (Fig. 199), the left border being usually unbroken, while
the other two shorter borders are broken into lobes. The longest
lobe stretches as far as the pylorus (Py), to which it is attached by
connective-tissue : the opposite extremity of the gland is attached to
the liver. .

The excretory duct of the pancreas (Ductus Wirsurgianus) opens
into the common bile-duct at about the middle of the pancreas
(P"); other smaller ducts may open into the same canal.

b. Minute structure. [The pancreas consists of a number of
lobes loosely held together by connective-tissue ; each lobe is com-
posed of a number of lobules attached to each other much more
intimately. The lobules are made up of tubes lined by a single
layer of glandular epithelium. This epithelium is, as a rule, broadly
columnar, but in the smaller tubes may be cubical or polygonal.
Each cell has a cell-wall, nucleus, and very granular protoplasm ;
the latter shows two zones (in the inactive condition), a granular
zone near the lumen, and an outer, clear, and finely striated zone
(Nussbaum). The lumen of each alveolus is very small, and in
many cases difficult to make out.

The smallest ducts have no special lining, and are therefore
bounded by the glandular cells; the Jarger ducts have a
flattened, cubical epithelium, which when seen from the sur-
face has an appearance as if the individual cells were widely
separated from one another; these ducts have a considerable
layer of connective-tissue around them. The largest ducts are
lined with a layer of columnar, ciliated epithelium; the cilia
are very long, usually of about the same length as the cell, some-
times appearing to be even longer. This epithelium is contin-
uous with the ciliated, epithelial layer of the common bile-duct,
which it resembles. These largest ducts have an extremely thick
layer of connective-tissue around them.

The pancreas and its ducts are very richly supplied with vessels
and nerves ; the nerves forming everywhere a fine plexus, the larger
strands of which usually, but not always, course with the larger

302 THE ALIMENTARY TRACT, ETC.

blood-vessels. The larger ducts have an especially rich supply of
nerves, of which fibrils may be traced towards the ciliated epithe-
lium ; an anatomical connection between the two has not, however,
been made out. |

Ill. THE SPLEEN.

a. General description. Although the spleen belongs to the
lymphatic system, it is considered here in order to complete the
description of the abdominal viscera. It is a small, rounded-oval
body, of a reddish-brown colour, suspended in the mesentery near
the anterior end of the large intestine (Fig. 184 Mz). In medium-
sized animals the longer diameter is about 6 mm., and is parallel
with the long axis of the body ; the shorter disseter is about
5 mm., and the thickness varies from about 3 mm. to 4 mm.
The ioral surface is flat or slightly concave (Hi/us lenis), and re-
ceives the relatively large afferent and efferent vessels ; the rest of
the organ is smooth and rounded, and with its greatest convexity
directed towards the left side.

b. [Minute structure. The structure of the spleen resembles
that of higher animals. It possesses a serous coat of peritoneum,
under which is a fibrous coat; the latter sends in trabeculae,
which divide and form a fine meshwork of supporting-tissue ; the
finest trabeculae are formed by the processes of the connective-cells
of the sustentacular structure. According to Hoffmann, the thick-
ness of the fibres averages o-oo1 to o’o1r mm.; the intervening
spaces measure 0'002 too7012 mm. The sauiée? are filled by the
spleen pulp, which consists of true spleen-corpuscles, blood-cor-
puscles, and pigment-corpuscles.

The spleen-corpuscles have an average diameter of o:co6 mm.,
and are round or of a rounded oval form. Each consists of a vielldeias
with a very small amount of adherent protoplasm ; the nucleus
possesses one or two nucleoli. Some of these cells contain a
brownish or black pigment in granules, but most of them are
colourless (Hoffmann).

The pigment-cells equal the white blood-corpuscles in size, and
exactly resemble the corresponding pigment-cells of the liver.

The blood-corpuscles are found in various stages of disintegra-
tion and regeneration.

THE SPLEEN. 303

The arteries, on entering the spleen, at once break up into
branches which pass in all directions, giving off twigs on all sides
and at varying angles; from these capillaries are supplied, which
traverse the parenchyma in all directions. The capillaries empty
themselves partly into veins, partly into the splenic spaces.

The veins commence either as capillaries in connection with the
arteries or by communicating with the splenic spaces. This com-
munication is brought about by small twigs of about o°o15 mm.
diameter, which have incomplete walls, and so open into the splenic
spaces (Hoffmann).

Malpighian bodies are represented by collections of splenic
cells on various arterial twigs ; they are, however, not so sharply
defined as is the case in some higher animals. j

IV. THE PERITONEUM.

a. General description. The peritoneum is a thin, pigmented
membrane lining the abdominal cavity. Tracing it forwards from
the ventral wall of the abdomen (Peritoneum parieta/e), it can be fol-
lowed along the deeper surface of the muscles to the pericardium.
The middle portion leaves the abdominal wall by accompanying the
anterior abdominal vein ; the lateral portions are continued further
forwards, and then ascend on the pericardium and the deeper sur-
faces of the lateral walls in the thoracic region.

The peritoneum passes thence to the ventral surface of the liver
(Ligamentum coronarium), covers this surface and passes on to the
dorsal surface of the organ, which, together with the gall-bladder, it
completely encloses. The membrane thus reaches the dorsal wall
(Ligamentum suspensorium hepatis et pericardii); from the lateral
borders: of the liver it passes upwards to the dorsal wall, and thus
forms a pocket-like pleuro-peritoneal cavity on either side.

From the dorsal wall and above the attachment of the coronary
ligament of the bladder the peritoneum reaches the root of the
lung on each side, and completely invests the organ: while in
the middle line it covers the outer surface of the oesophagus and
attaches it to the dorsal wall, thus forming the first part of the -
mesentery

304 THE ALIMENTARY TRACT, ETC.

Just behind the root of the lung, the peritoneum, in female speci-
mens, has an’ opening on each side (Ostiam abdominale tubae Fallo-
piae), by which the oviduct communicates with the peritoneal cavity.

Tracing the peritoneum backwards, it passes over the ventral sur-
face of the kidneys so as to exclude them from the peritoneal sac :
in the middle line, between the kidneys, the peritoneum descends to
form the mesentery for the small intestine. At the inner borders
of the kidneys, the testes or ovaries are pushed into the abdominal
sac, and so possess well-marked mesenteries; the mesovarium be-
comes longer towards the cloaca, but attains its greatest develop-
ment in the breeding season, when it is arranged in numerous folds.
Along the outer borders of the kidneys, in females, the peritoneum
again descends into the abdominal cavities to enclose the oviducts,
which have broad mesenteries. ‘Towards the rectum these mesen-
teries are shorter and attached to either side of the bladder by a
well-marked free border: as the middle line of the bladder is
attached by the peritoneum to the rectum, two distinet pouches
(Cava recto-resicalia) are formed, which descend deeply into the
pelvic cavity. The upper walls of these pouches are pushed in be-
tween the urostyle and the rectum, and together form a strong
meso-rectum, which is.longer near the Va/vula Bawhinii and con-
tinuous with the mesentery of the small intestine. The hinder
portion of this mesentery is very short, and only covers the lateral
walls of the rectum.

With the exception of a small portion of ite dorsal surface, which
is attached to the rectum, the whole surface of the bladder is covered
with peritoneum. .

The mesentery of the alimentary canal commences in connection
with the oesophagus between the roots of the lungs; it is attached
to the dorsal surface of the liver, covering the posterior caval vein,
and is attached to the gall-bladder. From this point it extends, as
a free, arched fold, to the concave right border of the stomach,
which is completely surrounded by peritoneum.

The gastro-duodenal fold (Ligamentum gastro-duodenale) extends
from the stomach to the pylorus and includes the pancreas. The
hepato-duodenal fold (Lig. hepato- ~duadentle) extends from the portal
fissure of the liver to the duodenum. —

The mesentery of the small intestine is broad and arranged in
folds, which follow the curves of the intestine; and is attached in
the middle line, immediately beneath the vertebrae, where it encloses
the aorta.

THE PERITONEUM. 305

The various folds and mesenteries carry the blood-vessels and
nerves to the different organs ; in this course the vessels are sur-
rounded by large lymphatics, which communicate with each other.

Fig. 201.

Preparations from the peritoneum of Rana esculenta.—G. H.

I From peritoneum of the ventral wall of abdomen, stained with silver and logwood (Hartnack,

Oc. I, Syst. 7).
II. From mesentery of small intestine of Rana esculenta, stained with silver (Hartnack, Oc. I,

Syst. 7).
Ill Preparation to show ciliated cells between non-ciliated cells ; after Neumann.
IV. Vertical section at border of liver to show ciliated epithelium ; after Neumann.

D Non-ciliated cells.

b. Minute structure (Fig. 201).

[The peritoneum is a serous membrane, formed for the most part
of a layer of irregular endothelial cells, arranged on a thin layer of
subserous, connective-tissue (Fig. 201 I, II, and ITI).

The endothelial cells are attached to each other by cement-sub-
stance, easily stained by silver nitrate. The cells covering the
general surface of the peritoneal cavity are larger and broader than
those covering the mesentery of the small intestine (compare I and
II, Fig. 201).

At various points stomata are found, bordered by smaller and
more deeply staining epithelium (I, 4). The membrane covering
the general cavity is also much more pigmented than that covering
the mesentery (compare I and II).

Various portions of the peritoneal surface possess ciliated cells,

x

306 THE ALIMENTARY TRACT, ETC.

and these cells are usually thicker than the surrounding non-ciliated
cells. Such cells are found especially near the openings of the ovi-
ducts and on the liver. The dimensions of the cells vary ; according
to Neumann the average dimensions of ciliated cells on the liver are :
0006 mm. depth (without the cilia); nucleus, 0-012 mm. long and
0003 mm. broad. ‘The cells are five- or six-sided and bounded by
straight sides (Neumann). |

SECTION VI.

THE LARYNX, LUNGS, VOCAL SACS, THYMUS AND
THYROID GLANDS, AND THE LYMPHATIC
GLANDS (TONSILS?) OF THE
HYOID REGION,

Vials tee uy
y sa TN

THE LARYNX, LUNGS, VOCAL SACS, ETC.

—<——
LITERATURE.

THE LUNGS AND LARYNX.

Arnold, J., Zur Histologie der Lungen des Frosches. Virchow’s Arch. 1863. Vol.
XXVIIE p. 433.

Auerbach, L., Ueber den Bau der Blutcapillaren in den Lungen des Frosches und
an einigen andern Orten. Ambtlicher Bericht tiber die vierzigste Versammlung
deutscher Naturforscher und Aerzte. 1886, p. 241.

Brittan, Brit. and Foreign Medico-chirurgical Review, 1857. Vol. XX.

Eberth, C. J., Ueber den feineren Bau der Lunge. Zeitschr. f. wiss. Zool. 1863.
Vol. XII, p. 427.

Eberth, C. J., Ueber den Bau und die Entwicklung der Blutcapillaren. Wirzburger
naturw. Zeit. 1866-67. Vol. VI, pp. 27-32.

Egorow, W., Ueber die Nerven der Lungen. Centralbl. f. med. Wiss. 1879, p. 305.

Elenz, E., Ueber das Lungenepithel. Wiirzburger naturw. Zeit. 1864. Vol. V,
pp. 66-84.

Frommann, C., Ueber die spontan, wie durch Durchleiten inducirter Stréme, an den
Blutzellen vy. Salamandra maculata und an den Flimmerzellen von der Rachen-
schleimhaut des Frosches eintretenden Veriinderungen. Jenaische Sitzungsb.
1880.

Gegenbaur, C., Ueber Driisenzellen in der Lungen-Schleimhaut bei Amphibien.
Arch. f. Anat. u. Physiol. 1863, p. 157.

Griffini, L., Contribuzione alla patol. del tessuto epiteliale cilindrico. Arch. per
le scienze mediche, 1884. Vol. VIII, pp. 1-43.

Gritzner, Physiologie der Stimme und Sprache. Hermann’s Handb. d. Physiol.
Vol. I, Pt. I, p. 146.

Henle, J., Vergleichende Anatomische Beschreibung des Kehlkopfes. Leipzig,
1839.

Hedioxon, C. K., in Bronn’s Klassen und Ordnungen des Thierreichs. Leipzig
und Heidelberg, 1873-78. Vol. VI, pp. 514-531.

Hoffmann, T., Die Lungengefisse der Rana temporaria. Dissert. Dorpat, 1875.

Holmgren, F., Upsala Lakareférenings Forhandlingar, 1867. Vol. III, pp.
389-399-

Howes, G. B., On a hitherto unrecognised feature in the larynx of the anurous
amphibia. Proc. Zool. Soc. London, 1887, p. 491.

Hiter, C., Ueber den Kreislauf und die Kreislaufsstérungen in der Froschlunge.
Centralbl. f. med. Wiss. 1873. Nos. 5 and 6.

Kandarazki, M., Ueber die Nerven der Respirationswege. Arch. f. Anat. u. Phys.
1881, p. I.

Kittner, Beitrag zu den Kreislaufsverhiltnissen in der Froschlunge. Virchow’s
Arch. 1874. Vol. LXI, p. 21.

Leydig, Anatomische-histologische Untersuchungen iiber Fische und Reptilien.
1853. ;

310 THE LARYNX, LUNGS, VOCAL SACS, ETC.

Malpighi, De pulmonibus. Oper. omn. Lugd. Batav. 1687. Vol. II, p. 328. ,

Miller, H., Ueber das Vorkommen glatter Muskelfasern in den Lungen der
Amphibien. Wiirzburger naturw. Zeit. 1861.

Pertik, O., Untersuchungen iiber Nervenfasern. Arch. f. mik. Anat. 1881; Vol.
XIX, p. 183.

Ranvier, L., Legons sur l’histologie du systeme nerveux. Vol. I, pp. 98-Io1.

Schestopol, A., Ueber die Durchlissigkeit der Froschlunge fiir geléste und kérnige
Farbstoffe. Virchow’s Arch. 1879. Vol. LXXYV, p. 199.

Schulize, F.E., Epithel und Driisenzellen. Arch. f. mik. Anat. 1867. Vol. III,
p- 145.

Schultze, F. E., Die Lungen, in Stricker’s Handbuch der Gewebelehre.

Stirling, W., On the nerves of the lungs of the newt. Journ. of Anat. and Physiol.
1882, p. 96.

Treviranus, C. R., Beobachtungen aus der Zootomie u. Physiologie; nach dessen
Tode herausgegeben von L. C. Treviranus. Bremen, 1839.

THE THYMUS GLAND.

Ecker, Blutgefiissdriisen, in Wagner’s Handwérterbuch der Physiologie, 1853. Vol.
TV, pFiAs

Fleisch, E., Ueber den Bau einiger sogenannten Driisen ohne Anew
Wiener Akad. Sitzungsb. 1870. Vol. LX, Pt. IT, p. 55.°

Gegenbaur, Vergleichende Anatomie.

Hoffmann, C. K., Bronn’s Klassen und Ordnungen des Thierreiches. 1873-1878.
Vol. VI, p. 503. .

Leydig, Lehrbuch der Histologie. 1857, p. 422.

Tolldt, Ueber lymphoide Organe der Amphibien. Wiener Acad. Sitzungsb. 1868.
Vole VII, PtH. p..272;

Watney, H., The minute anatomy of the thymus. Phil. Trans. 1882. Vol.
CLXXIII, p. 1100. yas :

THE THYROID GLAND.

Baber, E. C., Researches on the minute anatomy of the thyroid gland. Phil. Trans.
1881. Pt. III, p. 577.

Ecker, Blutgefissdriisen, in Wagner’s Handwérterbuch der Physiologie, 1853.
Vol. IV.

Fleisch, E., Ueber den Bau der sogenannten Schilddriise des Frosches. Wiener
Acad, Sitzungsb. 1868. Vol. LVIII, p. 57.

Hoffmann, C. K., Bronn’s Klassen und Ordnungen des Thierreiches. 1873-1878.
Vol. VI, p. 503.

Huxley and Martin, Practical Biology. 4th edit., 1877, p. 181.

Leydig, Lehrbuch der Histologie. 1857, p. 376.

Miller, J., Ueber die Entwicklung der Schilddriisen des Frosches. Wiener >
Sitzungsb. 1871. Vol. VI, pp. 428-553.

Miller, W., Ueber die Entwicklung der Schilddrtise. Jenaische Zeitschr. 1871.
Vol. VI, p. 438.

Ponicaré, Zur Anatomie der Glandula thyroidea. Journ. de l’anat. et de la
physiol. 1877. Vol. XIII, pp. 123-143.

Rolleston, Forms of Animal Life. 2nd Edit. 1888, p. 77.

Zeiss, O., Mikroskopische Untersuchungen iiber den Bau der Schilddriise. Dissert.
Strassburg, 1877.

THE LARYNX, LUNGS, VOCAL SAOS, ETC.

I. THE LARYNX.

Tue larynx (Fig. 202) is a short wide tube placed between
the posterior cornua of the hyoid, to which it is attached by
connective-tissue. The long axis of the tube lies in the median
line and almost horizontally, but the posterior end is on a slightly
lower level than Fig. io2.
the anterior, when
the animal is in
the natural sitting
position (Fig. 202).
The anterior end
of the larynx opens
into the mouth by
a longitudinal slit
(Fig. 179 Z), and
is placed in a slight
depression caused
by the folding of Dissection to show the position and relationsof the larynx. The animal

(Rana esculenta) is in the natural sitting position; the toes of the
the mucous mem- __ fore-foot are, however, too much flexed.—G. H.

B Brain.
brane; the poste- @ .Gall-bladder.
‘rior end communi- Re Garare (7 rnp mechecnaee
eates with the F_° False vocal cords.

eye Gg Epiglottis.
cavities of the 2 Bek

L- ? Liver.

lungs. P ' WV ‘True vocal cords.

The larynx is te

lmed with mucous membrane, which is continuous, in front with
that of the mouth, behind with that of the lungs. The organ
has a skeleton of cartilage, and possesses special muscles,

312 THE LARYNX, LUNGS, VOOAL SACS, ETC.

by which the supply of air to the lungs, and the voice can be
regulated.

a. The cartilages of the larynx.

The cartilages of the larynx are five in number, of which four are
paired and one is single.

(1) The cricoid cartilage (Figs. 203, 204) is an oval ring of
cartilage with various processes. The ring-like portion of the
cartilage is placed in a plane which is almost vertical, but which
is directed slightly upwards anteriorly, and slightly downwards
posteriorly (the animal being in the usual sitting position).

Fig. 203.

The cartilaginous skeleton of the larynx.

I. Seen from in front ; the spinous process would normally be more curved.
II. Seen from the left side ; the spinous process should be more curved,

Ca Right arytenoid cartilage. SR Opening to larynx.

Cal Left arytenoid cartilage. *** The two outer asterisks are above the two
C.11-C.1.4 Cricoid cartilage. apices of the left arytenoid cartilage; the
P Lateral plate of cricoid cartilage. middle one above the pre-arytenoid carti-
Sp Spine of cricoid cartilage. lage.

The sides of the ring are slightly curved inwards on the anterior
surface, and possessed of irregular enlargements (C./.'—-C./.*), the space
enclosed by this portion of the cartilage is occupied by a membrane
(IT), which forms the floor of the body of the larynx. :

From each side of the body of the cartilage, a process (C7?) is
given off, which curves backwards and inwards to join its fellow of
the opposite side, the two forming a blunt spinous process (Sy), which
projects backwards, and is intimately attached to the oesophagus.
Between these processes and the lower portion of the body of

THE LARYNX. 313

the cricoid cartilage are the apertures of the roots of the lungs
(Fig. 203), which, by their attachments to these cartilages, are
kept open.

(2) The arytenoid cartilages (Fig. 203 I, II, Ca, Ca) are a

pair of cartilages placed
in front of the cricoid
cartilage, one on each
side. Each cartilage is
semilunar in shape, con-

cave internally, and
convex externally. The
cartilages are placed

almost vertically, with
their posterior borders
or bases parallel to the
body of the cricoid car-
tilage. The superior
borders (Fig. 204) are
directed upwards and

forwards, the inferior.

downwards and_for-
wards. The superior
and inferior borders are
separated by a semicir-
cular notch, bounded by
‘two sharp apices. The
superior and inferior
angles of the two car-
tilages are close to-
gether, and movably
attached to each other
by connective-tissue.

These cartilages vary
very greatly in the two
sexes. In the males
they are thick, strong,

the cartilages are very
thin, more hollowed and
much smaller.

Fig. 204.

The larynx and surrounding parts, seen from the ventral
surface, .

Cal Arytenoid cartilages.

CB-Cl4 Cricoid cartilage.

G, Gl Fibrous tissue connect-
ing the larynx with
the posterior. cornua
of the hyoid.

HH Lesser cornaa of the
hyoid,

HH Greater cornua of the

ing the ring-like cri-
- coid cartilage. -

Pht The M. petrohyoideus
tertius,

S Part of tendon of M.
petrohyoideus ter-
tius.

SB, SB1 Mucous membrane
bulging from the an-
terior ventricle of the

larynx.

Sp Spinous process of the
cricoid cartilage.

ZK Body of the hyoid.

314 THE LARYNX, LUNGS, VOCAL SACS, ETC.

(3) [The pre-arytenoid cartilages (Fig. 206 I, P) are two small
elongated cartilages placed in the semicircular notch between the
superior and inferior borders of the arytenoid cartilages. They are
subject to much variation in size, sometimes being merely a very
slender rod, at others a moderately thick oval mass. In female
specimens they appear to be, at times, absent, or to unite with the
arytenoid cartilages, as in these cases a third very small apex
is found on each arytenoid cartilage; but it is always much smaller
than the two neighbouring apices. |

b. The attachments of the cartilages to each other.

The cartilages do not articulate directly with each other, but are
connected by connective-tissue only ; there are, therefore, no syno-
vial sacs.

The muscles of the larynx.
Al. Aperture between the arytenoid cartilages. HH Greater cornua of the hyoid.
C.l. Cricoid cartilage. Jt Fibrous tissue into which the two con-
C.a.1 Superior angle of the arytenoid cartilage. strictions are inserted.
C.a.l, M. constrictor aditus laryngis. Ph? Second petrohyoid muscle (M. petrohyoid.1).
C.0.l. M. hyo-arytenoideus anterior, Ph3 Third petrohyoid muscle (M. petrohyoid. IL),
C.0.1.1 M. hyo-arytenoideus posterior. Ph+ Fourth petrohyoid muscle (M. petrohyoid.
Dl, M. dilatator laryngis. III).
G Connective-tissue. S,Si,S2 Tendon of the fourth petrohyoid muscle,
Gl Connective-tissue. Sp Spinous process of the cricoid cartilage.
H Smaller posterior cornua of the hyoid, ZK Body of the hyoid.

e. The muscles of the larynx}.

The muscles of the larynx appear in the following order, when
dissected from the mouth :—

1 The nomenclature adopted is that of Henle and Hoffmann,

_—

THE LARYNX. 315

(1) The W. dilatator aditus laryngis (Henle), (Fig. 205 D./.) arises
on either side from the hinder end of the larger posterior cornu
of the hyoid: the fibres diverge slightly to be inserted into the
middle portion of the outer surface of the arytenoid cartilage; a
smaller bundle of fibres is attached to the deeper-lying constrictor
muscle and to the cricoid cartilage.

(2) The MW. constrictor aditus laryngis (Henle), (Fig. 205 C.a/.),
arises on either side from the hinder half of the dorsal surface of
the posterior cornu of the hyoid. The two muscles enclose the larynx,
and are inserted into a median tendinous raphe on the under sur-
face of the larynx (J¢). The raphe is connected with the skeleton
of the larynx by connective-tissue.

(3) The II. hyo-arytenoideus anterior (Fig. 205 C.0./.) arises on each
side from the inner border of the anterior end of the cornu of the
hyoid ; the muscle lies close to the anterior border of the arytenoid
cartilage, and is inserted into a fibrous lamella on the dorsal surface
of the larynx. The MW. petrohyoideus tertius is also partially inserted
into this lamella.

(4) The W. petrohyoideus tertius (Fig. 205 Ph*), (see also p. 66).
The greater part of this muscle is inserted into the end of the
posterior cornu of the hyoid (HH); a smaller portion (8, S?)

_is prolonged to be inserted into the cricoid cartilage and into the

fibrous lamella into which the WJ. hyo-arytenoidei anteriores are
inserted.

(5) The I. hyo-arytenoideus posterior (Fig. 205 C.o./) arises on
each side from the superior angle of the corresponding arytenoid
cartilage, under cover of the tendon of the M. petrohyoideus tertius.
The muscle is inserted into the inferior angle of the arytenoid
cartilage.

d. The interior of the larynx (Figs. 202, 206, 207). The cavity
of the larynx is constricted at two points: anteriorly it is con-
stricted by the true vocal cords (Figs. 206 V, 207 SB), posteriggly by
the false vocal cords. The whole cavity is lined with mygéus mem-
brane, which is continuous with that of the mouth anteriorly, with
that of the lungs posteriorly.

(1) The true vocal cords are two vertical flat bands of con-
nective-tissue, attached above to the superior angles of the arytenoid
cartilages, below to their inferior angles ; their anterior borders are
thin and free ; near their posterior borders they are attached by
mucous membrane to the internal surfaces of the arytenoid cartilages.

316 THE LARYNX, LUNGS, VOCAL SACS, ETC.

The anterior and posterior borders are not parallel but are each~
concave (Fig. 202 /’). 3
"Figs 266. The anterior border is thin,
the posterior thick and rounded.
Seen from in front (Fig. 206),
the opening between the cords
(Rima glottidis) is slightly wider
at each end than in the middle.
The ends of the concave poste-
rior border are prolonged back-
wards and enclosed in a fold of
mucous membrane. Part of the
tissue enclosed is unstriated mus-
cular fibre, which may be traced
to the cricoid cartilage.

(2) [The false vocal cords
(Figs. 202 and 206 /’) are simply
Three sections through the larynx of Rana folds of mucous membrane,

esculenta.—G. H. : :
I. Sagittal section near the median plane which extend vertically on each
through the larynx. side of the larynx behind the
II. Oblique transverse section through larynx.
III. Almost horizontal section through larynx. true vocal cords; they do not

4 psi he rise ee extend so far towards the me-
NE Epiglottis. dian plane as do the true vocal
\F False vocal cords, d
~ G@ Epiglotidean glands. cor s.|
—H Hyoid. Vi :
M Membranous floor of the larynx, cut (3) [The entricles of the
obliquely. larynx (Figs. 202 and 206) are
O Opening into root of lung. >
P Pre-arytenoid cartilage. two on each side. The anterior
PR Ae re ah ventricles are between the true

vocal cords and the arytenoid cartilages; they are open anteriorly,
and closed by mucous membrane posteriorly.

The posterior ventricles open towards the median plane, each
presenting an oval opening (Fig. 202), which widens outwards into
a large cavity (Fig..206 ZZ). The cavity is bounded in front by
the base of the true vocal cord, and the mucous membrane attached
to it; posteriorly by the false vocal cord, and externally by the
cricoid cartilage and the connective-tissue capsule of the larynx. |

(4) [The mucous membrane of the larynx varies in struc-
ture in various parts of the organ. From the anterior opening
of the larynx to the posterior borders of the vocal cords it is
lined with stratified epithelium, which is firmly attached to the
underlying structures by a small amount of sub-epithelial

ve EEEoEEEeEeEEeEeEeEerooo

THE LARYNX. SET

tissue. This is especially well marked on the vocal cords
themselves. is

’ Behind the vocal cords the mucous membrane
is much more loosely attached to the surrounding
structures by an extremely vascular areolar tissue.
The epithelium is arranged in a single layer
of columnar cells, among which are numerous
goblet-cells. In the more external parts of the
posterior ventricles, the mucous membrane is
thrown into deep folds and so forms polygonal
acini. In the median line of the floor of the
larynx and behind the false vocal cords is a
vertical fold of mucous membrane, which in-
creases in height and breadth as it proceeds 4,, pimactottidis, seen
backwards towards the roots of the lungs. The from the front.
mucous membrane behind the true vocal cords ©, Tima siottidis.
is extremely ‘vascular, in the most posterior
portion of the larynx the blood-vessels form a capillary network
exactly like that of the lungs. |

e. [The epiglottis (Fig. 206 F) is a small bilobed fold of mucous
membrane placed on the floor of the mouth in the median plane and
immediately in front of the aperture to the larynx. Between it
and the mucous membrane covering the arytenoid cartilages are a
number of large mucous glands(G). The epiglottis does not contain
cartilage ; it is, however, constant in its appearance and sharply
marked off from the surrounding mucous membrane. |

Ul. THE LUNGS.

a. General description. The lungs are two large thin-walled
sacs (Figs. 185 and 204 Lg and Jy’). The roots of the lungs are
contracted at their origin from the larynx and then expand to form
two ellipsoid sacs, which terminate posteriorly in bluntly-pointed
ends. With the exception of their roots they lie entirely free in
the pleuro-peritoneal cavity, and are covered by the pleuro-peri-
toneal membrane. In the recent state they have a bright red
colour due to the large supply of blood-vessels.

b. Minute structure.

(1) The museular tissue of the lungs is for the most part
arranged in large bands, which form a coarse network on the deeper

ii

318 THE LARYNX, LUNGS, VOCAL SACS, BTC.

surface of the organ; when seen in section! (PI. II, Fig. 208 4, B)
these bands are found to be composed of well-developed involun-
tary muscular fibres. Between the larger bands are smaller bands
having a similar arrangement. From these networks of muscular
bands finer processes of muscular tissue pass peripherally towards
the surface of the organ, and are attached to the thin and incom-
plete muscular layer found in the wall of the lung (C).

(2) The connective-tissue of the lungs is present in only small
quantity, but is still sufficient to fill m the spaces between the
various muscular bands and the surface of the lung, and to invest
the whole of that surface. There is thus formed a series of pits,
the mouths of which open into the general cavity of the lung,
while their bases are at the surface. Through this connective-
tissue course the blood-vessels, nerves, and lymphatics. It contains
numerous yellow elastic fibres.

(3) The blood-vessels of the lungs. The pulmonary artery,
courses along the outer surface of the lung to the apex, giving
off, at wight: angles, lateral branches in the whole of its course ;
these show a tendency to be alternately larger and smaller. The
lateral branches divide and form a rich capillary network (T.
Hoffmann). |

The capillary network has very small meshes; the diameter of a
given mesh being frequently less than that of the capillary bounding
it. The meshes are rounded or polygonal in shape.

The pulmonary vein arises by lateral branches from this capillary
network ; the branches join, at right angles, the main vein, which
courses from the apex of the lung along its inner surface to the
root of the organ.

(4) The epithelium of the lungs. Externally the lungs are
covered with a layer of endothelium derived from the peritoneum.
Internally the surface is covered with an epithelium which varies
considerably in different positions.

On the free borders of the muscular trabeculae forming the

' See Plate II, Fig. 208.

Two sections from the lung of Rana temporaria ; stained with borax carmine.—G. H.
I. The lung dilated (Hartnack, Oc. I, Syst. 3).
Il. The lung contracted (Hartnack, Oc. I, Syst. 7).

A Band of muscle cut transversely. B_ Band of muscle cut longitudinally.
C Muscular layer of surface.

THE LUNGS. 319

borders of the alveoli is a short columnar ciliated epithelium (Fig.
208); such epithelium is also found in the root of the lung; it
contains goblet-cells.

The alveoli, for the most part, are lined with a single layer
of tesselated epithelium; the cells are polygonal in outline,
with finely granular contents and a distinct nucleus: the average
diameter of the cells is from 0°0074 to o-o108 mm., that of the
nucleus 0°0054 mm., that of the nucleolus o‘ooog mm.; four to
eight of such cells occupy the space enclosed by one mesh of the
capillary network (Eberth).

The epithelium rests on a structureless basement membrane, which
is continuous over the whole inner surface of the lung, whereas the
epithelium does not pass over the capillaries, and is therefore only
found in isolated patches in the areas enclosed by the capillaries
(Eberth).

In various isolated spots, small groups of short columnar or
goblet-cells are found in the tesselated epithelium (Eberth, Hoff-

(5) [The lymphatics of the lungs have been described by T. Hoff-
mann; they form a network of vessels surrounding the larger
blood-vessels: from this branches are given off, which form a
network of fine canals through the whole of the lung; part of this
- secondary network accompanies the blood-capillaries, but other
portions run a separate course. They communicate with the
pleuro-peritoneal cavity.

(6) The pigment-cells are very numerous, branched, and large ;
they accompany the lymphatics, and not the blood-vessels (T. Hoff-

(7) The nerves of the lungs (p. 172) course along the larger blood-
vessels, under the serous coat; the fibres are chiefly medullated
fibres (Egorow, Kandarazki). Non-medullated branches, which form
a plexus in each alveolus, are given off. The branches have small
triangular enlargements (ganglia), where they unite. The nerves
are accompanied by nerve-cells, which occur either singly or in
groups.

Egorow describes the nerves as being distributed in three net-
works: one for the mucous membrane and muscular trabeculae; a

second for the superficial muscular layer; and a third for the serous
membrane. |

320 THE LARYNX, LUNGS, VOCAL SACS, ETC.

Ill. THE VOCAL SACS.

a. General description. The vocal sacs are a pair of sacs
which open in the floor of the
mouth (Fig.179 8); they are found
only in the males. When the
animal croaks these sacs are di-
lated and act as resonators; when
so dilated the sacs force up the
skin under the angle of the mouth
and tympanic membrane. In well-
developed specimens they are about

_as large as an average sized cherry.
The skin covering the sacs is ex-

Dissection to show the vocal sac of the tremely elastic, but is not directly

Fig. 209.

Seago pe attached to the sacs.

HH Larger posterior cornua of the hyoid.

HH) Smaller posterior cornua of the hyoid. b. Minute structure. The sac
My Mylo-hyoid muscle, : : : :
My Mylo-hyoid muscle continued on to Consists of connective-tissue, with

the vocal sac. ; 7

Thy eee a large proportion of yellow elastic
VH Anterior cornua of the hyoid, fibre. Internally it is lined with

Z Body of the hyoid. : :
‘ ‘ a flattened epithelium, and exter-

nally is covered with a layer of striated muscular fibre, derived
from the mylo-hyoid muscle (Fig. 209 My, My’).

IV. THE-THYMUS GLAND.

a. General description. The thymus gland (Fig. 210 7/)is placed
on each side behind the angle of the jaw; it is best exposed by re-
moving the skin behind the tympanic membrane and the angle of
the jaw, and then reflecting the I/. depressor mandibulae (D.m.). The
gland is then found as an elongated, oval body, not quite 3 mm.
long, lying in the space between the I. depressor mandibulae and
the M. sternocleidomas toideus (St); it extends slightly beyond the
posterior border of the former muscle. The space also includes
connective-tissue, fat, and numerous vessels,

In Rana temporaria this gland is spherical, much smaller, and
placed further behind on the I. sternocletdomastoidens, between the
M. latissimus dorsi and the M. deltordeus (Wiedersheim).

THE THYMUS GLAND. _ 321

b. Minute structure (Fig. 211).

[The gland is surrounded by a connective capsule, which is

indented on the mner surface to form

a hilus through which blood-vessels-

course into the organ.

The capsule sends in numerous fine
trabeculae, which form a connective-
tissue skeleton such as is found in all
lymphatic glands. The corpuscles of

the trabeculae possess elongated nuclei,

from o-o1g to o'028 mm. in length,
and o'o1o to 0015 mm. in breadth
(Tolldt). The trabeculae support a
network of blood-vessels.

The meshes of this sustentacular
tissue are filled with cells; these are :

Fig. 210

Dissection to show relations of the
thymus gland.

De. M. deltoideus.

D.m.M. depressor mandibulae.

L.d. M, latissimus dorsi.

St M. sternocleidomastoideus.

Tf Tympanic membrane.

Th Thymus gland.

(a) Lymphoid cells, rounded or oval, possessing a round nucleus
and nucleolus, and an extremely small amount of adhering proto-
plasm; the size of the nucleus is from o‘orr to o'015 mm.

(Tolldt).
Fig. 211.

From yarious sections from the thymus gland of Rana esculenta.—G. H.

I. Complete gland (Hartnack, Oc. I, Syst. 3)-
a Pigment-cells.

IL Portion of a section (Hartnack, Oc. I, Syst. 7) showing small corpuscles of Hassall.
IIL. Portion of a section showing lobules with degenerating cells.

a Capsule of lobe.
6 Lobules.

e Large corpuscle of Hassall, surrounded by normal tissue.

IV. Nerve-cell? (corpuscle of Hassall), after Fleischl

(8) Corpuseles of Hassall (Fig. 211 II, III, and IV) are, as a
rule, large bodies, but are subject to much variation in size. Their

Y

322 THE LARYNX, LUNGS, VOCAL SAGS, ETC.

general appearance is seen in Fig. 211 III; they show a concentric
striation and usually enclose one or more smaller cells. They

therefore closely resemble similar corpuscles found in higher
animals,

(y) In many frogs the cellular structure of at least a part of
the gland seems to have undergone a degenerative stage (III). In
such cases the connective-tissue is increased in quantity, and marks
off portions of the section into small lobules (III) which are
filled with cells containing mucus or sometimes fat (III). Under
what conditions this degeneration, if such it be, takes place has
not yet been determined ?.

(6) Large branched pigment-cells are found in the course of the
larger blood-vessels.

(«) Watney describes also four varieties of ‘ granular cells :’
1. polygonal or rounded; 2. vacuolated; 3. spheroidal masses ;
4. club-shaped masses attached to the blood-vessels. I have, how-
ever, not been able to distinguish them. |

[Tolldt (2. c. 1868) described the lymphoid tissue and the blood-vessels of this gland
but did not find the corpuscles of Hassall.

Fleisch] (/.c. 1870) disputed Tolldt’s description ; he evidently found the corpuscles
of Hassall (see Fig. 211 IV), but he held them to be nerve-cells, and described them
as such. He was also of opinion that the blood-vessels open into the intercellular
spaces (as in the spleen). This has not been found to be the case by any other
observer. Watney (/.c, 1882) first described the concentric corpuscles of Hassall
as such.

Most writers describe the parenchyma as arranged in lobules. This I have only
seen in a part of the gland and under what I believe to be pathological conditions. ]

V. THE THYROID GLAND.

a. General description. A thyroid gland (Fig. 209 Thy) is
found on either side as a small, triangular, or oval, reddish-coloured
body on the dorsal surface of the I. sternohyoideus, just before
it passes between the MIM. genio-hyoidei. It lies in the angle
formed between the larger and smaller posterior cornua of the
hyoid (7H, HH"). It is easily found by the presence of a large
number of vessels in its neighbourhood, and especially by the
large jugular vein, to the ventral surface of which it is intimately
attached.

‘ Only winter-frogs were at my disposal (translator).

THE THYROID GLAND. 323

Not uncommonly several smaller supplemental glands are found
in the rich anastomosis surrounding the organ.

The dorsal surface of the
gland is lobulated, the ventral
surface flatter and convex.
The glands of opposite sides
are seldom symmetrical.

b. Minute structure (Fig.
212 I and II). [The gland
possesses a connective-tissue
capsule, which sends in trabe-
culae to support the vesicles of
which the gland is composed.

_ The vesicles (I and It),
which vary greatly in size, are
closed cavities, usually of a
rounded or oval form, but some-
times branched (Baber). Each
vesicle is lined with a single
layer of cubical or slightly
columnar epithelium (II, 2),
which rests on a delicate
basement-membrane of con-
nective-tissue, placed between
the epithelium and the sur-

rounding: lymphatics (Baber).
Zeiss describes o delicate reti- Minute structure of the thyroid gland of Rana
culum between the epithelial esculenta.—G. H.
eells. I, agers a heakray the gland (Hartnack, Oc. I, “
The vesicles always contain 1, small portion of above (Hartnack, Oc. I,
mucus (4), and are surrounded Syst. 7).

a _ Epithelium lining the vesicles.

by a fine anastomosis of blood- = Mucus,
vessels (ce) | c Blood-vessels, injected with blue mass.

VI. THE LYMPHATIC GLANDS OF THE HYOID
REGION (TONSILS %).

_ a. [General description. These are two oval, reddish-coloured,

soft lymphatic glands, placed one on each side of the larynx.

Frequently they are divided into two or three lobes by more or less.
xa

324 THE LARYNX, LUNGS, VOCAL SACS, ETC.

deep fissures. They are constant in their occurrence, and are
frequently supplemented by one or: more smaller glands; each
the dae: gland has the larynx on its mner
iss side, the Vena jugularis externally,
the M. omohyoideus in front, and
above the mucous membrane of
the pharynx (Tolldt).

b. Minute structure, The
glands consist of dense lymphoid
tissue (Fig. 213), but possess in
addition one or more large bodies
(2) which resemble lymphoid fol-
licles in structure. Each is com-
posed of a dense mass of small
cells; and the whole follicle is, as

Part of section through the lymphatic gland, ee A 3 .
(tonsil ?) of Rana esculenta (Hartnack, Oc.1, In similar follicles of higher ani-

Syst. 13),—G. H.
a Extremely large lymphoid follicle.

mals, sharply differentiated from
_ the rest of the organ.

The glands possess an extremely rich vascular supply, and are
frequently pierced by one or more large arterial trunks.

The mucous membrane covering the glands is thinner than that
immediately around, but is not perforated. |

[As far as I am aware, Tolldt is the only observer who describes these glands: he
makes no mention of the lymphoid follicles. }

oe RT oie

SECTION VIL.

THE URINO-GENITAL SYSTEM, THE ADRENALS,
AND THE FAT-BODIES.

THE URINO-GENITAL SYSTEM, ETC.

LITERATURE.

THE URINO-GENITAL ORGANS.

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Amphibien. Anat. Anzeiger. 1886.

Knappe, E., Das Biddersche Organ. Morph. Jahrb. 1886. Vol. XI, pp. 489-548.

Kolessnikow, N., Ueber die Eierentwicklung bei Batrachiern und Knochenfischen.
Arch. f. mik. Anat. 1878. Vol. XV, p. 382.

v. Kélliker, A., Gewebelehre. Fifth Edition.

Langer, C., Ueber das Lymphgefiisssystem des Frosches. Wiener Acad. Sitzungsb.
1867. Vol. LV, Pt. I, p. 621.

Lavdowsky, M., Ueber die Endigung der Nerven in der Harnblase des Frosches.
Centralbl. f. a. med. Wiss. 1871, p. 33.

Lavdowsky, M., Die feinere Structur und die Nervenendigungen der Froschharn-
blase. Arch. f. Anat. u. Physiol. 1872, p. 55.

Lereboullet, A., Recherches sur l’anatomie des organes génitaux des animaux verté-
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328 THE URINO-GENITAL SYSTEM, THE ADRENALS, ETC.

Leydig, F., Anatom.-histol. Untersuchungen iiber Fische und Reptilien.

Leydig, F., Lehrbuch der Histologie des Menschen und der Thiere. Frankfurt,
1857, p. 508.

Leydig, F., Untersuchungen zur Anatomie und Histologie der Thiere. Bonn, 1883.

List, J. H., Ueber Becherzellen im Blasenepithel des Frosches. Wiener Sitzungsb.
1884, Vol. LXX XIX, Pt. III, pp. 186-210; also in Arch. f. mik. Anat. 1887,
Vol. XXIX, p. 147.

List, J. H., Ueber Becherzellen im kangal crams des Frosches. Zool. Anzeiger,
1884. No. 169, p. 328.

List, J. H., Ueber einzellige Driisen im Blasénepithiele der Amphibien. Biol. Cen-
tralbl. 1885. Vol. V, p. 499.
Loos, P. A., Die Eiweissdriisen d. Amphibien und Vogel. Zeitsch. f. wiss. Zool.

1881. Vol. XXXV, pp. 478-504.

Maier, R., Die Ganglien in den harnabfiihrenden Wegen des Menschen und einiger
Thiere, Virchow’s Arch. 1881. Vol. LXXXYV, pp. 49-71.

Marcussen, J., Ueber die Cloake und Harnblase der Frésche. Bull. der phys.-math.
Acad. de St. Pétersbourg, 1853. Vol. XI.

Marshall, A. M., On certain abnormal conditions of the reproductive organs in the
frog. Journ, of Anat. and Physiol. 1884. Vol. XVIII, p. 121.

Marshall, A. M., The frog. Manchester and London. 2nd Edit. 1885.

Mecznikow, E., Zur vergleichenden Histologie der Niere. Gittinger Nachrichten,
1866, p. 61.

Meyer, F., Beitrag zur Anatomie des Urogenitalsystems der Selachier und Am-
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Moleschott, Hin histochemischer und ein histologischer Beitrag zur Kenntniss der

Nieren.

Miescher, Die Spermatozoen einiger Wirbelthiere. Verhandl. d. naturf. Gesell. in
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Neumann, E., Untersuchungen tiber die Entwickelung der Spermatozoiden. Cen-
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Neumann, E., Untersuchungen iiber die Entwickelung der Spermatozoiden, Arch.
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Neumann and Grunau, Driisen der Froscheileiter. Arch. f. mik. Anat. 1875. Vol.
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Nussbaum, N., Ueber die Niere der Wirbelthiere. Sitzungsber. Bonn, 1870.

Nussbaum, N., Ueber die Endigung der Wimpertrichter in der Anurenniere.
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Nussbaum, N., Ueber den Bau und die Thitigkeit der Driisen. Arch. f. mik. Anat.
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Nussbaum, N., Ueber die Secretion der Niere und iiber die Verbindung der
Samen und harnbereitenden Driisenschliuche in den Nieren der Batrachier.
Sitzungsb. d. niederrheinischen naturf. Gesell. in Bonn, 1877. Vol. XXXIV,
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Nussbaum, N., Ueber die Endigung der Wimpertrichter der Niere der Anuren.
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Nussbaum, N., Zur Differenzirung des Geschlechts im Thierreich. Arch, f. mik.
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Peltier, Sur les zoospermes de Ja grenouille. L’Institut. 1838. Vol. VI.

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Prévost, Note sur les animalcules spermatiques de la grenouille et de la Salamandre.
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1841-1842. Vol. IX, p. 289.

LITERATURE. 329

Rathke, H., Beitrige zur Geschichte der Thierwelt, ITI Abth.; and Neueste Schr.
d. naturf. Gesell. in Danzig. 1825. Vol. I.

Reger, R., Ueber die Malpighischen Kniuel der Nieren und ihre sogenannten
Capseln. Arch. f. Anat. u. Physiol. 1864, p. 537.

Reichert, On kidney. Jahresbericht tiber Anatomie in Arch. f. Anat. u. Physiol.
1843, p- 220, etc.

Remak, Untersuchungen iiber die Entwicklung d. Wirbelthiere, p. 128.

Retzius, G., Zur Kenntniss der Spermatozoen. Biol. Untersuchungen. 1881.

Rideward, W. G., On an abnormal genital system in a male of the common frog.
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Robinson, C., Ueber die Lymphgefisse der abdominal Kingeweide des Frosches.
Froriep’s Noten: 1846. No. 807, col. 225.

Résel, A. J., Historia naturalis ranarum nostralium. 1758, p. 28.

Roth, Untecsuchimgen tiber die Driisensubstanz der Niere. Bern, 1864; and
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Schiefferdecker, Ueber einzellige Driisen in der Blase der Amphibien. Bericht.
d. naturf. Ges. in Rostock, 1883.

Schultze, F. E., Das Driisenepithel der schlauchférmigen Driisen des Diinn- und
Dickdarms und die Becherzellen (Cloaca of frog), Centralbl. f. d. med. Wiss.
1866, p. 161.

Schultze, M., Observationes nonnullae de ovornm ranarum segmentatione. Bonn,
1863.

Schultze, O., Untersuchungen iiber die Reifung und Befruchtung des Amphibieneies.
Zeitsch. f. wiss. Zool. 1887. Vol. XLV, pp. 177-226.

Schweigger-Seidel, F., Ueber die Samenkérperchen und ihre Entwicklung. Arch.
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Spengel, J. W., Das Urogenitalsystem der Amphibien. Arbeiten aus d. Zool. Inst.
in Witndarg, 1876. Vol. III, pp. 1-114.

Spengel, J. W., Wimpertrichter in der Amphibienniere. Centralbl. f. d. med.
Wiss. 1875, p- 369.

Swammerdam, J., Bibblia naturae. Leydae, 1738. Vol. LI, p. 796.

Thompson, A., Article ‘Ovum’ in Todd’s Cyclopedia of Anatomy and Physiology,
London, 1879. Vol. V, p. 91.

Tolotschinoff, Ueber das Verhalten der Nerven zu den glatten Muskelfasern der
Froschharnblase. Arch. f. mik. Anat. 1869. Vol. V, p. 509.

Tornier, O., Ueber Biirstenbesiitze am Driisenepithel. Arch. f. mik. Anat. 1886.
Vol. XX VII, p. 181.

v. la Valette St. George, Spermatologische Beitrage. Arch. f. mik. Anat. 1886,
Vol. XXVIL, p. 385; and in Stricker’s Gewebelehre, Article ‘ Hoden.”

Valentin, On kidney. Repertitorium, 1845. Vol. VIII, p. 92.

Waldeyer, W., Eierstock und Ei. Ein Beitrag zur Anatomie und Entwick-
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Weldon, W. F. R., On the suprarenal bodies of vertebrata. Quart. Journ. Micros.
Sci. 1885. Vol. XXV, p. 137.

v. Wittich, W., Beitrage zur morphologischen und histologischen Entwicklung der
Harn- und Geschlechtswerkzeuge der nackten Amphibien. Zeitsch. f. wiss. Zool.
1853. Vol. IV, p. 152.

Wolff, W., Die Innervation der glatten Muskulatur. Arch. f. mik. Anat. 1882.
Vol. XX, p. 361.

350 THE URINO-GENITAL SYSTEM, THE ADRENALS, ETC,

THE ADRENALS.

Bergmann, De glandulis suprarenalibus. Dissert. Gittingen, 1839.

Ecker, A., Der feinere Bau der Nebennieren beim Menschen und den vier Wirbel-
thierklassen. Braunschweig, 1846.

Frey, H., On the suprarenal capsules, in Todd’s Cyclopedia. London, 1849, p. 827.

Giles, A. E., On the development of the fat-bodies in the frog. Quart. Journ.
Micros. Sci.

Hoffmann, C. K., Bronn’s Klasseri und Ordnungen des Thierreichs. Heidelberg
und. Leipzig, 1873-1878. Vol. VI, p. 506.

v. Kélliker, A., Handbuch der mikroskopischen Anatomie, Leipzig, 1854. Vol. II,
p. 386.

Leydig, Lehrbuch der Histologie. Frankfurt a. M, 1857.

Moers, Ueber den feineren Bau der Nebennieren, Virchow’s Arch. 1864. Vol.
XXTIX, p. 336.

Nagel, Ueber die Structur der Nebennieren, Arch. f. Anat. u. Physiol. 1830, p. 377.

THE FAT-BODIES.

Carus, Lehrbuch der Zootomie, Leipzig, 1818 (describes the fat-bodies as supra-
renals). :

Hoffmann, C. K., Bronn’s Klassen und Ordnungen des Thierreichs. Heidelberg
und Leipzig, 1873-1878. Vol. VI.

Marshall, A. Milnes, The frog. Manchester and London, 1884.

v. Wittich, W., Beitrige zur morphologischen und histologischen Entwicklung der
Harn- und Geschlechtswerkzeuge der nackten Amphibien. Zeitsch. f. wiss. Zool.
1853. Vol. IV, p. 152.

THE URINO-GENITAL SYSTEM, THE
ADRENALS, ETC.

THE URINO-GENITAL SYSTEM.

By cutting threzgh the meso-rectum the posterior caval vein is
seen, as a large vessel, arising by numerous transverse branches from

the ventral surfaces of the kidneys
and testes (Fig. 214 Cv), lying in
the median line between the kid-
neys; by drawing it to one side the
dorsal aorta is brought into view
(Fig. 214 do). The testes are placed
on the ventral surface of the kidneys’
and together with the fat-bodies
conceal the anterior portions of these
organs. The posterior portions of
the kidneys are covered by perito-
neum only, and may by seen with-
out further dissection. The kidneys
lie dorsal to the peritoneum, and have
this membrane on their ventral
surfaces only ; their dorsal surfaces
are in contact with the lumbo-
sacral plexus.

The ureters extend from the
anterior border of the eighth verte-
bra to the middle of the urostyle,
where they terminate by two orifices
in the dorsal wall of the cloaca
(Fig. 184).

The testes are entirely surrounded
by peritoneum, except a small part
(Hi/us) of the inner surface, where
the vessels and ducts enter.

Fig. 214.
“Cy, Ao

Wey!
The male urino-genital organs,

Ao Aorta,

cl Cloaca. vv

Ce Inferior vena cava.

FK Fat-body.«

H Testis./ _

N KidneyA~

S.S1 Openings of ureters.

Ur Ureter.

Vr Renal veins.

+ Appearance of ureters on the ven-

tral surfaces of kidneys,-

The urino-genital organs are arranged in the same manner in
the two sexes; the ovaries cérresponding in position with the

332 THE URINO-GENITAL SYSTEM, THE ADRENALS, BTC.

testes (Fig. 214), that is, they are bilaterally symmetrical, and
placed on the ventral surfaces of the kidneys.

The oviducts (Fig. 224 Ov) lie externally to the kidneys and
ovaries, and course through the whole length of the trunk from the
roots of the lungs to the cloaca. The size of the ovaries and oviducts
varies very greatly according to the season of the year; at times,
the kidneys may be entirely hidden by them.

I. THE URINARY ORGANS.
A. The kidneys.

a. General description. Hach kidney (Fig. 215) is a reddish-
brown, elongated organ, almost semilunar in shape; the inner
border being straight and the outer convex.
The organ is flattened from above down-
wards, and decreases in thickness towards
either end. In animals of average size
the kidney is about 16 mm. long, and
from 6 to 7 mm. broad. The kidneys
lie parallel to the vertebrae.

The outer border is smooth and even, except atits posterior third,
where a slight depression for the ureter exists; the inner border
has usually two or three well-marked notches, the hmdermost of
which is the deepest (Fig. 215). Each notch is continued outwards
as a groove, traversing the whole breadth of the ventral surface
and containing a branch of the renal portal vein. The ventral
surface is, as a whole, slightly concave, grooved, and lobulated ;
the dorsal surface is smooth and slightly convex.

Fig. 215.

The right kidney, seen from the
ventral surface,

b. [Minute structure. The kidney is enclosed in a thin capsule
of fibrous tissue (Fig. 220 By), which sends in fine trabeculae to
support the glandular structures and the blood-vessels. |

(1) The blood-vessels of the kidney are the renal veins, the renal
arteries, and the renal portal vein.

a. The renal portal vein (p. 247) courses along the outer border
of the posterior part of the kidney, and then along the outer margin
of the dorsal surface; in this course it gives off large branches,
which course inwards and forwards and supply numerous lateral
twigs. “These anastomose to form a network of vessels on the
dorsal surface of the organ, from which very numerous large
branches course downwards and ‘somewhat inwards to jom corre-
sponding branches of the renal veins (Fig. 216 I).

THE URINARY ORGANS, 333

Fig. 216.

0
*

x See .
ey -We ¢ : gy

The blood-vessels and lymphatics of the kidney.—G. H.

I. Transverse vertical section through kidney. Venous system blue; arteries red (Hartnack,
Oc. I, Syst. 3).
IL. Part of a horizontal section through kidney. Venous system blue; arteries red (Hartnack,
Oc. I, Syst. 3).
III. Part of a transverse vertical section through kidney ; lymphatics blue (Hartnack, Oc. I, Syst. 7).
A Ventral surface.
B_ Dorsal surface.
C Two arterial twigs uniting before entering the Malpighian body.

8. The renal veins (p. 247) form a coarse plexus on the ventral
surface of the kidney, from this numerous large branches (Fig. 216 I)
course upwards and outwards.

The venous system between the renal portal veins on the dorsal
surface, and the renal veins on the ventral surface, are so large that
they can scarcely be named capillaries (Hyrtl).

y. The renal arteries (p. 233) are distributed to the ventral
surface of the kidney ; their mode of distribution varies in different
parts of the organ. A simple arrangement is that shown in
Fig. 216 I, where a branch traverses the breadth of the kidney and
gives off branches to the Malpighian corpuscles; in one case (C)

334 THE URINO-GENITAL SYSTEM, THE ADRENALS, BTC.

I have seen two twigs passing to the same corpuscle; as a rule,
however, each Malpighian corpuscle receives only one twig. A more
general arrangement is that the artery courses nearer the ventral
surface and in a more winding course, several twigs are then given
off close together, from the convex surface of one of the curves, and
these course to their respective corpuscles.

In the Malpighian corpuscle the arterial twig forms a series of
loops and then passes out to open abruptly into one of the branches
of the neighbouring venous anastomosis (Hyrtl).

(2) [The Malpighian corpuscles and their capsules (Figs. 216 I,
218 III). The corpuscles lie nearer the ventral than the dorsal
surface. They are rounded oval bodies, formed of loops of an
arterial twig, held together by a small amount of connective-tissue.
Each corpuscle is enclosed in a capsule, which it incompletely fills
(Fig. 217)1.

The capsules are formed of connective-tissue and lined with a
flattened epithelium (Fig. 218 III): according to Duncan the fibrous
coat is arranged in two layers (III a). Towards the opening of the
uriniferous tube the epithelium increases in thickness.

According to Hyrtl, the corpuscles are arranged in two layers, a
more superficial one and a deeper one; and are of two sizes, the
larger being as a rule the more superficial (ventral).]

(3) [The uriniferous tubes (Figs. 217 and 218). Each tube
originates at a narrow opening on the dorsal surface of a Mal-
pighian capsule. The tube gradually widens and is lined with
a short rounded or cubical epithelium (Roth), (Fig. 218 IIT); each
epithelial cell bearing a small number of extremely small cilia (Bow-
man, Kdélliker, Duncan, and others). The cilia of the cells nearest
the capsule are directed towards it (Heidenhain), those of the cells
further away have an opposite direction (Spengel). This portion of
the tube is known as the neck ; it courses dorsalwards.

The second portion of the tube (Zubulus contortus), (Fig. 218
III, IX, and XII) has a very tortuous course in the dorsal part
of the kidney, and then winds towards the ventral surface. This
portion is lined with columnar epithelium, which has granular
contents, and possesses large distinct nuclei. The cells of this part

! See Plate IT.

Portions of two transverse vertical sections through the kidney.—G. H.

I. Kidney of Rana esculenta, partial injection of the uriniferous tubes with silver nitrate
(Hartnack, Oc, I, Syst. 7).
IJ, Kidney of Rana temporaria, stained with borax-carmine (Hartnack, Oc. I, Syst. 7).

THE URINARY ORGANS. 335

Fig. 218.

3 -

From the third part of a uriniferous tube; short ciliated epithelium, borax-carmine (Hart-
nack, Oc. I, Syst. 7).—G. H. :

A ighian corpuscle and capsule ; shows the capsule of two layers at a. After Duncan.

Part of uriniferous tube after natural injection with sulphindigotate of sodium (Hartnack,
Oc. I, Syst. 3).—G. H.

Transverse section of one of the larger branches of the ureter, from Rana esculenta (Hartnack,
Oc. I, Syst. 7} H.

Epithelial lining of the ureter itself while stillin the kidney (Hartnack, Oc. I, Syst. 7).—G. H.

Portion of a uriniferous collecting-tube from section in Fig. 217 I, stained with silver (Hart-
nack, Oc. I, Syst. 7).—G. H.

Renal epithelium ; a to b, tubulus contortus ; 6 to c, third portion of uriniferous tube ; ¢ to d,
fourth portion of tube. After Heidenhain (enlarged 210 times

Ciliated cells of the neck, after Duncan.

Isolated rod-cells of Triton taeniatus, after Heidenhain.

Isolated rod-cells, after Heidenhain (enlarged 300 times).

Isolated cells of the neck, after Heidenhain (enlarged 210 times

).
. Portion of the fourth part of a uriniferous tube, after Heidenhain (enlarged 300 times).
. Ciliated epithelium of tubulus contortus, after Tornier (magnified 550 times',
i pengel,

From kidney of Rana temporaria, after S
a Uriniferous tube opening into seminiferous duct.
6 Dilated seminiferous duct cut longitudinally.
¢ Yas efferens cut transversely.

336 THE URINO-GENITAL SYSTEM, THE ADRENALS, ETC.

of the kidney are usually: more or less coloured with a golden-
yellow pigment. According to Tornier it bears short cilia (Fig.
218 XIV).

The third portion corresponds with the narrow limb of Henle’s
loop; it is led with ciliated epithelium (Fig. 218 VIII, 4 to c),
similar to that in the neck of the tube.

The fourth portion (Fig. 218 VIII, ¢ to d, and XIII) repre-
sents the wider limb of -Henle’s loop. It has a winding course
in the ventral part of the kidney, and then ascends dorsally to
open into a collecting-tube. The fourth part of the tube is lined
with a short, columnar epithelium (Fig. 218 VIII, ¢ to d), which
has a clear, cuticular, free border, large nucleus, and a peculiar
arrangement of the protoplasm, which shows a rod-like structure
(Fig. 218 X1).

The collecting-tubes course transversely near the dorsal surface
of the kidney (Fig. 217), and the uriniferous tubes meet them at
right-angles. They are lined with a short polygonal epithelium
(Fig. 218 VII).

The peritoneal funnels of the kidney (nephrostomes). Spengel, Meyer, and
Hoffmann describe these funnels as existing in the frog; according to them they
open on the ventral surface by narrow apertures, and each is connected, by a vertical
tubule, with the fourth part of the uriniferous tube (Spengel), but according to
Nussbaum, with the neck of the tube. According to Spengel and Meyer the number
of these funnels is in Rana from 250 to 360.

According to Wiedersheim the funnels hang free from the ventral surface like so
many parasites attached by fine filaments, and do no¢ open on the surface.

Heidenhain (Arch. f. mik. Anat., Vol. X) was unable to find these organs.

Being unable to find any trace of these organs in the kidneys of either R. tempo-
raria or R. esculenta, in microscopic sections or in teased preparations, I inserted
canulae into the ureters of both male and female specimens of both species, and
injected the uriniferous tubes with a solution of Berlin blue. Although the tubules
were, in some cases, completely injected, in no case could I find any trace of a
peritoneal funnel, nor was there any escape of the solution from the kidney as would
be the case if the funnels were open and communicated with any part of the uri-
niferous tubes. Even when the pressure was increased to the extent of a column
of 25 cm. high of the injection-mass, no escape took place from the surface of the
kidney, though in numerous cases the uriniferous tubes were ruptured by the abnor-
mally high pressure.

Properly dissected frogs were placed in 0-6 °/, sodium chloride solution, in which
finely divided gamboge was suspended. No trace of ciliary action was, in any case,
found on either surface of the kidneys,

One may therefore conclude that if the peritoneal funnels exist in the adult frog
(1) they are very difficult to find; (2) they do not form a free’communicating path
between any part of the uriniferous tubes and the abdominal cavity; (3) their
superficial terminations have no free cilia. As before stated I have found no
trace of any such organs. :

THE URINARY ORGANS. 337

The lobules of the kidney. When treated with proper reagents
the kidney shows a marked tendency to separate into lobules (Fig.
219 1).

ne lymphatics of the kidney (Fig. 216 II") form an irregular
network of fine canals with elongated meshes. They run chiefly
in the direction of the blood-vessels. The large vessels, which
supply the kidney, are surrounded by large lymphatics.]

The nerves of the kidney (Fig. 219 II)’. Little is known of
these. Nerve-fibres have been traced alongside the larger blood-
vessel through the greater part of the kidney.

B. The ureters.

a. General description. In the males the ureters are, at the
same time, the seminiferous ducts. Each ureter commences on the
dorsal surface of the kidney by bifurcating branches, which are
continuous with the collecting-tubes of the kidney. In the anterior
two-thirds of the kidney the ureter is wholly on the dorsal surface ;
at the junction of the middle and posterior thirds it winds round to
the outer border of the kidney (Fig. 214 Ur), and there lies in a
groove accompanied by the renal portal vein (Fig. 220 Ur and /a),
the two organs being intimately attached to the kidney substance
and.enclosed by the fibrous capsule (By).

This portion of the ureter possesses a spindle-shaped iitacleuat,
which represents the Receptacu/um seminis. In Rana temporaria the
Receptaculum seminis forms a large saccular dilatation.

In its further course the ureter runs backwards and slightly
inwards, converging with its fellow of the opposite side; the ureters
lie free in the abdominal cavity, and terminate by two openings
placed side by side in a groove on the dorsal wall of the cloaca
(Fig. 214 8, 81).

In females the ureters are intimately attached to the dilated
oviduct, immediately after leaving the kidney; they pursue a
similar course to those of the males, but are attached to the oviduct
in the whole of their course to the cloaca.

b. Minute structure. The ureter is a tube composed of connective-

? See Plate IT.
Two portions from a gold preparation of the kidney of Rana esculenta.—G. H.

I, Showing the tendency to split into lobules,
IL. Nerve-fibres accompanying the blood-vessels.
a _ Blood-vessels.
b Nerves.

Z

338 THE URINO-GENITAL SYSTEM, THE ADRENALS, ETC.

tissue and involuntary muscular fibre, and lined with a mucous
membrane. The mucous membrane is thrown into longitudinal
folds, and consists, in the larger tubes, of two or three layers of
epithelium (Fig. 218 V), that on the
free surface is columnar; the deeper
cells being rounded or polygonal.
The larger branches of the ureter are
lined with columnar epithelium (Fig.
218 VI), with small intervening cells.
In some parts of the branches the
columnar epithelium bears short cilia.
No glands have been found in the
ureter or Leceptaculum seminis; in
Rana temporaria, however, the Recep-
taculum seminis possesses large, branch-
ing mucous glands (Wiedersheim).

C. The bladder.
a. General description. ‘lhe uri-

Transverse section of the kidney, ° 2

stad: nary bladder (Fig. 185 //2) is closely
Tip Genesee teas cates: attached to the ventral wall of the
D - Dorsal surtace. cloaca and: is easily distended from
NC Renal parenchyma. . 3 :
Ur Ureter. that organ. In relation to the animal
V Ventral surface. ae f ] % 2
Fi) Helin) poktad sock. it is of very large size; in consequence

of its being contracted in the middle
it has two lobes, which may be of unequal size. The organ is
somewhat heart-shaped (Figs. 184 and 185), with the narrow neck
attached to the cloaca, into which it opens by a smaller aperture on
the ventral surface. The aperture is surrounded by a small fold of
mucous membrane.

b. |Minute structure. The urinary bladder is bounded by a
thin, transparent wall, lined internally with mucous membrane, and
eovered externally by peritoneum.

(1) The muscular coat is formed of a network of fine bands of
unstriated muscular fibre (Fig. 221); it is supported and completed
by a connective-tissue layer, rich in connective-tissue corpuscles and
yellow elastic fibres.

(2) The peritoneal coat is a single layer of endothelial cells
derived from the peritoneum and resting on a very thin layer of
subperitoneal tissue.

‘THE URINARY ORGANS. 339

(3) The mucous coat is formed of epithelium resting on a layer of
loose, areolar tissue. The epithelium (Fig. 221 I, I, and IV) is

Fig. 221.

Various preparations from the bladder.

1. Silver preparation of the mucous membrane ; seen from the surface. After List (enlarged
400 times).
a Cells of the surface.
d_ Goblet-cells.
e Young cells.
IL. Vertical section of the mucous membrane ; after List (enlarged 600 times).

a Cells of upper Jayer.
b Cells of middle layer.
e Cells of lower layer.

Il, Large multicellular ganglion ; after Wolff.

IV. Vertical section from a silver preparation of the mucous membrane ; after List (enlarged 600
times).
a Upper layer.
& Middle layer.
e Lower layer.
ad Goblet-cells,

Y. Small ganglion of bladder ; after Wolff.
: a Non-medullated nerve-fibre leading to ganglion.
6 «Process of a ganglion cell.

arranged in three layers: the cells of the uppermost (II and
IV, a) always present a flat or convex border to the cavity of the
organ; seen from their free surfaces (I) they have polygonal out-
lines intermixed with round apertures belonging to goblet-cells, the
remaining surfaces of these cells are serrated. The cells of the
middle layer (II and IV, 4) are polygonal in outline, they are not
so tall as the cells of the layer above ; all their borders are serrated.
The cells of the deepest layer (II and IV, ¢) are more or less pointed
above where they project between the cells of the second layer ; their
lowest surfaces are flattened towards the subepithelial tissue, and
all their surfaces are serrated.
z2

340 THE URINO-GENITAL SYSTEM, THE ADRENALS, ETC.

The cells of all three layers possess a cell-wall, and finely gran-
ular contents, and each cell has a large oval nucleus (List).

The goblet-cells (Fig. 221 I and IV, d) vary very much in shape ;
they are always more or less rounded in outline: they vary greatly
in size (from 190 « to 54 pw in length); some possess ‘ feet’ or basal
prolongations, in others these are absent. They usually open freely
by rounded apertures on the surface of the mucous membrane,
but are sometimes closed. The nucleus is placed towards the base
of the cell and surrounded by a smaller or larger amount of proto-
plasm. These cells usually extend into the middle layer of the
epithelium, and they probably constitute unicellular mucous glands _

(List). .

(4) The blood-vessels of the urinary bladder (p. 235) are very
numerous and run in very tortuous courses; they are accompanied
by large lymphatics and by nerves.

(5) The nerves of the urinary bladder (p. 191) are of both medul-
_ lated and non-medullated fibres, which course together towards
their points of distribution ; the non-medullated fibres are, however,
much more frequent than the medullated fibres (Wolff).

The non-medullated nerve-fibres stand in close relation with the
nerve-ganglia of the bladder.. These ganglia may be unicellular, or
composed of groups of nerve-cells ; the cells vary considerably in
shape, round, oval, triangular, and other forms being equally
frequent in their occurrence; to some extent the form appears to
depend upon the number and position of the processes of the cells.
The diameter of the cells varies from 0°05 mm. to o°1 mm.; the
nucleus has a diameter of 0'025 mm., that of the nucleolus measures
0005 mm. (Wolff).

The cells may be unipolar or multipolar; the former are however
_ rare. The processes of these cells supply the muscle-fibres (Fig.
221 V, a), and other non-medullated processes connect the cells
with the nerves (V, 4 (Wolff) ).

The number of muscular fibres is far in excess of the number of
the fibres of distribution of the ganglia ; Wolff hence concludes
that the nervous impulse may pass from one muscle-fibre to
another. |

THE REPRODUCTIVE ORGANS. 341

Il THE REPRODUCTIVE ORGANS.

A. The male reproductive organs are the testes and their
ducts.

a. General description. The relations of the testes have
already been given (p. 234); the organs vary much in shape
and size in different individuals and with the different seasons ;
when greatest they are spherical, or of a rounded oval form, occasion-
ally cone-shaped or pear-shaped. The surface of the testes is not

Fig. 222. .
I IL.

Sa ial a |

smooth, but presents a series of convexities, each corresponding
to a lobule of the gland. At the 4z/us on the inner border the vessels
pass to and from the organ, and the Vasa ejferentia leave the testis.

The number of Vasa efferentia (Fig. 222 I and II) is subject to -
considerable variation, not only in different animals, but on the
two sides of the same animal. In some cases these ducts form a
network (I), in other cases this is absent (II); usually the ducts

342 THE URINO-GENITAL SYSTEM, THE ADRENALS, ETC.

bifureate at acute angles, just before entering the kidney. Most of
the tubes so formed open into the collecting-tube ; a few, however,

Fig. 223.

Various preparations from the testis.
I. Various stages of the spermatozoa ; from testis of Rana temporaria. After Neumann.
II. Section from testis of Rana eseulenta (Hartnack, Oc. I, Syst. 7).—G. H.
a Thin connective-tissue capsule.
b Trabeculae,
candd Seminiferous tubes.
III. From testis of Rana temporaria. After Neumann.
« Rounded epithelium of seminiferous tubes.
y Spermatoblasts.
IV. Surface view of seminiferous tube of Rana temporaria. After Neumann.
a Granular protoplasmic feet of spermatoblasts.
b Rounded epitnelium,

end blindly in the mesorchium (I, +). The course of the Vasa efferentia
from the testis is first inwards, within the mesorchium ; on reaching
the kidney they curve dorsalwards between that organ and the

THE REPRODUCTIVE ORGANS. 343

corresponding testis: the ducts then travel in the ventral surface
of the kidney towards its inner border, where they open into a
longitudinal canal (Bidder), (Fig. 222 I, L). Just before their
terminations each duct has an enlargement (I, C), the exact import
of which is unknown (see also Fig. 218 XV).

The collecting-tubes open into the ureter at the hinder extremity
of the kidney. _ A :

b. [Minute structure. The testis possesses a thin connective-
tissue capsule underneath its peritoneal covering (Fig. 223 II, a);
this sends in trabeculae (4) towards the centre of the organ, and so
encloses the separate lobules. Each seminiferous tube arises from an
elongated irregular sinus placed towards the middle of the organ ;
the tubes (c) are slightly convoluted in their course towards the
periphery, near which they branch (Spengel). The tubes are from
0°16 mm. to 0°12 mm. in diameter (Kolliker), and are lined with
two kinds of cells (Fig. 222 III); the cells (z) nearer the periphery
are rounded and have large rounded nuclei, the diameters of which
vary from 0-013 to 0°02 mm.; these again possess large and
distinct nucleoli. The other cells (y) are of elongated, spindle-
shaped form; and have oval nuclei, with an average length of
o'016 mm. say an average breadth of 0005 mm. (Neumann).

The rounded cells lie in groups which vary in thickness and
arrangement, and are often compressed so as to have polygonal
outlines. The spindle cells are arranged so as to radiate from the
lumen of the tube to the periphery, at an angle which varies from
45 to go degrees ; these are the spermatoblasts.

s The various changes which the spermatoblasts undergo in the
formation of spermatozoa will easily be understood by reference to
Fig. 223 I, a to &, where i and & represent the fully developed
spermatozoa. These have three parts, head, middle part, and tail,
the respective lengths of which in the two species are, according to
Neumann, the following :—

Head. Middle part. Tail.
Rana esculenta o'o140 mm. 070025 mm. 0o'040 mm.
Rana temporaria - o°c066 ., 070330 , 07045 ,,

At the hilus of the testis the rounded cells of the seminiferous
tubes are gradually modified to form short cylindrical cells (o-o1
mm. long and 0-006 mm. broad), the spindle cells being absent
(Neumann). The Vasa efferentia are also lined with a similar
columnar epithelium (Spengel).]

344 THE URINO-GENITAL SYSTEM,

THE ADRENALS, ETC.

B. The female reproductive organs.
The position of these organs has already been given (p. 335).

I. The ovaries.

Fig. 224.

The female reproductive organs; the ovary of the right
side has been removed,

N Kidney.

_0.T. Opening of the ov iduct into pleuro- -peritoneal cavity.

Ov Oviduct.
Ova Ovary.

P Opening of oviduct into the cloaca.

S, Sl Openings of the ureters.

Ut Dilated hinder portion of the ov iduct.

t Groove i in which ureters lie.
*

b. Minute structure.

Fold in groove separating the openings of the ureters.

a. General description.
Each sac-like ovary (Fig.
224) is subdivided by thin-

- walled septa into numerous

complete chambers, to the
inner walls of which the
ova are attached. The
walls of adjacent sacs ate
intimately attached to each
other, and the subdivision
corresponds with the ex-
ternal lobulated appearance
of the organ. According
to Spengel the number of
lobules is about fifteen
(Rathke nine to thirteen,

_ Brandt nine). Whether

this segmentation of the
ovary corresponds with the
segmentation of the body
has not been determined
(Spengel). No part corre-
sponding with Bidder’s
organ has been found in
Rana esculenta.

During the breeding
season the ovaries undergo
an extraordinary increase in
size so as to occupy the
greater part of the body-
cavity and to displace the
other viscera. The ovaries
are entirely surrounded by
peritoneum.

[The layer of peritoneum covering the

ovary possesses cilia (Thiry), the ciliated cells being arranged in
isolated patches (Schweigger-Seidel, Waldeyer) on the ventral surface

of the organ, and on the mesovarium ;

these patches are some-

THE REPRODUCTIVE ORGANS. 345

times united by very fine connecting lines of ciliated epithelium ;
the ciliated epithelium is always sharply marked off from that
surrounding it (Kolessnikow). Under the peritoneum is a thin
layer of connective-tissue, which is prolonged inwards to form
the septa above-described. To these septa are attached the ova.

Between the connective-tissue layer and the peritoneum are
isolated patches of germinal epithelium (Fig. 225 IV); these are
easily distmguished, by the rounded outlines of their cells, from the
surrounding epithelial cells (Waldeyer, Kolessnikow). These
patches of germinal epithelium measure from 0°0g3—0°186 mm.
in diameter; the germinal cells average 0°0139-0°0232 mm.* in
diameter (Kolessnikow). The patches are most numerous on the
outer surface of the ovary, and particularly so near the mesovarium.

The follicles contained im the ovary have a connective-tissue coat
developed in a manner similar to that of higher animals; the
primordial ova which they contain have large nuclei (0°0325 mm.).
The epithelium of the follicles has an average diameter of 0°0232-
0°0325 mm. (Kolessnikow).

Schultze’s description of the ovaries (/.¢.) varies considerably
from that of Waldeyer and Kolessnikow. Briefly he describes the
ovaries as a series of sacs separated by and lined externally and
internally by endothelium ; between these two layers are found
the germinal epithelium and follicles: the structures being held
together by an extremely minute quantity of connective-tissue. |

Il. The oviducts. -

a. General description. In young animals the oviducts are
quite straight, thin-walled, and of small calibre. During the
breeding season, however, they undergo an immense increase in
size, and become much convoluted ; in this state they are forced in
between the other abdominal viscera, and usually cover the whole of
the kidneys, and sometimes even part of the ovaries (Fig. 224 Or).

The openings of the oviducts into the pleuro-peritoneal cavity
(p. 304) are semilunar slits, directed inwards and lined with ciliated
epithelium (p. 306).

Immediately behind this opening (Ostivm abdominale) the ovi-
duct is contracted, and is there narrower than in the rest of its
length ; beyond this it expands, and then retains an even size
nearly to its hinder extremity, where it suddenly expands (Fig.
224 Ut). This dilatation gradually diminishes in size as it pro-
ceeds backwards towards the cloaca, into which each tube opens on
a small papilla. The dilated portions of the tubes lie close together,

346 THE URINO-GENITAL SYSTEM, THE ADRENALS, ETC.

but do not communicate with each other; the opening of the nght
tube is always slightly behind that of the left side (Fig. 224 P).
From the papillae, into which the oviducts open, a fold of mucous
membrane extends backwards on the dorsal surface of the cloaca to
meet its fellow of the opposite side at an acute angle (Fig. 224 *).
The orifices of the ureters are placed within these folds.

b. Minute structure.

(1) The tubular portion of the oviduct has three walls:
a peritoneal covering with sub-peritoneal tissue (a); a glandular
layer (4); and an epithelial lining (c). Of these the glandular
layer forms by far the thickest layer, especially during the
breeding season, when it is much increased in thickness. It
consists of long cylindrical glands, often bifurcated at their blind,
peritoneal ends. The epithelial cells, with which they are lined,

Fig. 225.

Preparations from ovary and oviduct.

I. Ciliated epithelium and goblet-cells of the oviduct ; after Neumann.
Il. Isolated goblet-cells and secretory cells from oviduct ; after Neumann.
a, b, ¢ Goblet-cells,
d, e, f Secretory cells after treatment with Miiller’s fluid.
2 Stoma of secretory cells,

Ill. Surface view of the ovary ; after Kolessnikow.
a Peritoneal endothelium,
6 Germin»] epithelium.
have the power of absorbing more than a hundred times their own
weight of water (Boettcher). This layer is absent at the anterior

opening of the oviduct.

THE REPRODUCTIVE ORGANS. — 347

The cells have an average diameter of oo12 mm., the lumen of
the individual glands 0-1 mm. (in spirit-hardened specimens, Neu-
mann). The cells contain small rounded bodies of very varying
size, which may exist singly, grouped, or even arranged in rows ;
they swell on the addition of water. Each cell possesses, in addition,
an oval, granular, distinct nucleus. When treated with Muller’s fluid
many of the secretory cells have the appearances shown in Fig. 225
II, d, e, f; they each possess an opening (),(Neumann).

According to Neumann the great power of absorbing water,
which the oviducts possess, is due to the presence of these bodies,
which he names ‘colloid granules.” The mucous secretion of
these glands passes into the oviduct and surrounds the eggs on
their passage towards the cloaca: it is due to this secretion that the
egg-spawn is so extremely slippery and difficult to handle.

The inner surface of the oviducts is lined with a ciliated, columnar
epithelium (Fig. 225 1), containing numerous goblet-cells (I and I).

(2) The dilated portion of the oviduct has much thinner walls
than the anterior, narrower portion ; the glands cease abruptly at the
junction of the two parts. The outer coat also contains unstriated
muscular fibre; the inner surface is lined with ciliated epithelium
similar to that of the anterior portion.

The lymphatics of the oviducts form a net with polygonal
meshes on their outer surfaces ; from this branches pass inwards in
the spaces between adjacent glands to the inner surface, where a
network with elongated meshes is formed (Langer).

C. [The Cloaca. |
a. General description. The cloaca is a short tube lying
beneath the urostyle; anteriorly it receives the openings of the
ureters, rectum, and bladder; and in the female the openings of
the oviducts, in addition : posteriorly it terminates at the anus.

b. Minute structure. The cloaca is lined internally with a
mucous membrane resembling that of the rectum, ¢.g. a simple
layer of columnar epithelium, which rests on a submucous, areolar
layer.

The outer walls consist of a thick superficial, longitudinal mus-
cular layer, and a deeper, ill-developed, transverse muscular layer.

ec. Special muscles of the cloaca.

(1) The MW. sphincter ani surrounds the end of the cloaca from the
anus to the tip of the urostyle. It consists of striated muscle.

348

THE URINO-GENITAL SYSTEM, THE ADRENALS, ETC.

(2) The I. compressor cloacae arises from the tip of the urostyle,
and is inserted into the hinder end of the rectum; it is also
attached to the symphysis of the iliac bones; from this point a few
fibres pass to the anus (Hoffmann). ]

a.

Cl

Ill. THE ADRENALS.

General description.
Fig. 226.

The male urino-genital organs.
Ao Aorta.

Cloaca.

Cv Inferior vena cava.
FK Fat-body.

N
8,
i

Kidney.
S1 Openings of ureters.
Testis.

Ur Ureter.
Vr Rehal veins.

t

a.

Appearance of ureters on the ven-
tral surfaces of kidneys.

The adrenals are small yellow bodies

attached to the renal veins on
the ventral surface of the kid-

‘ ney, towards its outer border.

b. [Minute structure. The
superficial layer of the adrenals
consists of solid, rounded, or
elongated groups of polygonal
cells, containing numerous fat-
granules; these represent the
cortical substance of the corre-
sponding organs of higher ani-
mals. The medullary part is
present only in small quantity ;
it consists of small groups of
polygonal cells, placed between
trabeculae of connective-tissue ;
both trabeculae and _ cell-groups
are covered with an endothelium.
The whole organ is surrounded
by a connective-tissue capsule,
which sends in trabeculae to
support the parenchyma (Hoff- —
mann). :

No nerves have been traced into
these organs (Eberth).]

IV. THE FAT-BODIES.

General description.

The fat-bodies (Fig. 226) are bright:

yellow, lobulated bodies, placed in front of the testes and ovaries
respectively. The greater portion of each organ lies parallel to the
long axis of the body, and from its anterior, posterior, and external

THE FAT-BODIES. 349

borders are given off finger-like processes ; these may divide dicho-
tomously either near the base or more peripherally. The external
processes are much the longest, and in the male often conceal the
greater part of the testis (Fig. 226 FK). The organs vary greatly
in size with the season of the year.

Fig. 227.

Two preparations from the fat-body of Rana esculenta1.—G. H.
I. Section of fat-body, stained with borax-carmine{Hartnack, Oc. I, Syst. 7).

Il. Three lobes of fat-body of Rana esculenta ; coarsely injected (Hartnack, Oc. I, Syst. 3).
Arteries striped. Veins shaded. :

b. [Minute structure. Each organ is completely surrounded by
peritoneum, under which is a very fine layer of connective-tissue.
The interior of the organ (Fig. 227 I) consists of large fat-cells
with small patches of adenoid tissue interspersed. The organs are
extremely vascular; each lobe has a main artery which gives off
lateral branches: each of these immediately divides to form two
vessels, which run in opposite directions and’ almost parallel with
the main stem; the vessels then break up into a fine network of

capillaries]

* From specimens collected in November.

SECTION VIII.

THE SKIN AND THE SENSE-ORGANS.

THE SKIN AND THE SENSE-ORGANS.

LITERATURE.

I. THE SKIN.

Ascherson, Ueber die Hautdriisen der Frische. Arch. f. Anat, u. Physiol. 1810,
p- 15.

Axmann, Beitriige zur mikroskopischen Anatomie und Physiologie des Ganglien-
nervensystems. 1853.

de Betta, Erpétologia delle provincie Venete e del Tirolo meridionale. 1857.

= SBiesiadecki, Ueber Basenbildung und Epithelregeneration an der Schwimmhaut

des Frosches. Untersuchungen aus d. Krakauer path.-anatom. Institut. 1872,
-_ pp. 60-84. Abstract in Centralbl. f. d. med. Wiss. 1873, No. 7, p. 106.

Bimmermann; E. H., Ueber den Einfluss der Nerven auf die Pigmentzellen des
Frosches. Dissert. Strasburg, 1878.

Bimmermann, E. H., Ueber den Einfluss der Nerven auf die Pigmentzellen des
Frosches. Centralbl. f. d. med. Wiss. 1879, p- 545.

de Blainville, M. H. M. Ducrotay, De l’Organisation des animaux. Paris, 1822,
Do. 145,995. _-.%

Bolaw, Beitrag zor Kenntniss der Amphibienhaut. Gdttingen, 1866.

Bruch, Beitrage zur Naturgeschichte und Classification der nackten Amphibien.
Wiirzburger naturwiss. Zeitsch. 1864. Vol. III.

Bricke, Untersuchungen iiber den Farbenwechsel des afrikanischen Chamaeleon.
Sitzungsb. der Wiener Acad. 1852. Vol. IV, P. 196.

Bugnion, Recherches sur les organes sensitifs qui se trouyent dans l’épiderme du
Protée et de lAxolotl. Dissert. Ziirich.

Canini, A., Die Endigungen der Nerven in der Haut des Froschlarvenschwanzes.
Arch. f. Anat. u. Physiol. 1880, pp. 143-153-

Ciaccio, J. V., Intorno alla minuta fabbrica della pella della Rana esculenta.
Palermo, 1866. Giornale di Scienze naturali ed economiche. Vol. II, pp.
103-158.

Ciaccio, J. V., On the distribution of the nerves to the skin of the frog, with
physiological remarks on the ganglia connected with the cerebro-spinal nerves.
Trans. Micros. Soc. London, 1864. Vol. XII, pp. 15-31.

Czermak, J. N., Ueber die Hautnerven des Frosches. Arch. f. Anat. u. Physiol.
1849, p. 252.

Da Collin, Danemarks Froer og Tudser. Naturhist. Tidsskrift. 1870.

Dewitz, Ueber das verschiedene Aussehen der gereizten und ruhenden Driisen im
Sehenballe des Laubfrosches. Biol. Centralbl. 1883, p. 558.

Dogiel, Neue Untersuchungen fiber den pupillenerweiterden Muskel, ete. Arch. f.
mik. Anat. 1886. Vol. XX VII, p. 403.

Duméril et Bibron, Erpétologie générale. 1841. Vol. VIII.

Aa

354 THE SKIN AND THE SENSE-ORGANS.

Eberth, C. J., Untersuchungen zur normalen und path. Anatomie der Froschhaut.
Leipzig, 1869.

Eberth, C. J., Zur Entwickelung der Gewebe im Schwanze der Froschlarven.
Arch. f, mik, Anat. 1866. Vol. II, pp. 490-503.

Eckhard, Ueber den Bau der Hautdriisen der Kréten und die Abhangigkeit der
Entleerung ihres Secretes vom centralen Nervensystem. Arch. f. Anat. u.
Physiol. 1849.

Ehrmann, S., Ueber Nervenendigungen in den Pigmentzellen der Froschhaut.
Sitzungsb. der Wiener Acad. 1882. Vol. LX XXIV, Pt. ITI, pp. 165-170.
Engelmann, T. W., Pfliiger’s Arch. f. d. ges. Physiol. 1871, Vol. IV, p. 321, and

1872, Vol. V, pp. 500-513. (Contractile glands in skin of frog.)

Harless, E., Ueber die Chromatophoren des Frosches. Zeitsch. f. wiss. Zool. 1854,
Vol. Se p- 372; also in Miinchener Gelehrten Anzeiger, 1853, No. 35.

Harley, G., On the organs of cutaneous respiration; principally on those of Rana
temporaria. Trans. Micros. Soc. London, 1857. Vol. V, p. 148.

Hensche, A., Ueber die Driisen und glatten Muskeln in der fusseren Haut von
Rana temporaria. Zeitsch. f. wiss. Zool. 1856. Vol. VII, p. 273.

Henslow, Way in which toads shed their skin. Annals of Nat. History, 1850,
p- 69.

Hoffmann, C. K., Bronn’s Klassen und Ordnungen des Thierreichs. Leipzig und
Heidelberg, 1873-1878. Vol. VI.

Huber, O., Ueber Brustwarzen bei Rana temporaria, L. Zeitsch. f. wiss. Zool. 1887.
Vol. XLY, p- 664.

Huizinga, D., Untersuchungen itiber die Innervation der Gefiisze in dar Schwimm-
haut des Froeches. Pfliiger’s Arch. 1875. Vol. XI, p. 207.

Huxley, H. T., Tegumentary organs. Todd and Bowman’s Cyclopedia of Anat.
and Physiol. p. 500. ri

Klein, E., On the lymphatic system of the skin and mucous membranes. Quart.
Journ. Micros. Sci. 1881. Vol. XXI, pp. 379-406.

Kdlliker, A., Stiftchenzellen in der Epidermis von Froschlarven. Zoolog. Anzeiger.
1885.

Krause, Handbuch der Gewebelehre. 1862.

Krukenberg, C. F. W., Die Hautfarbstoffe der Amphibien, in Vergleich. physiol.
Studien, by same author, 1882, pp. 43-49. ,

Kutschenko, N., Ueber die Krappfirbung der Froschgewebe. Arch, f. mik. Anat,
1882. Vol. XXVIII, pp. 360-364.

Langer, Ueber das Lymphgefisssystem des Frosches. Wiener Sitzungsberichte.
1867.. Vol. LV, pp. 593-636.

Langerhans, Anat.-hist. Untersuchungen iiber Fische und Reptilien. Berlin,
1853. Journal de Medicine. Vol. XI.

Leboucq, H., Recherches sur le développement et la terminaison des nerfs chez
les larves des Batraciens. Bull. de l’acad. roy. de Belgique. 1876. Vol. XLI, p. 4.

Leydig, F., Histologisch-anatomische Untersuchungen iiber Fische und Reptilien.
1853.

Leydig, F., Tastkérperchen und Muskelstruktur. Arch. f. Anat. u. Physiol. 1856,
Pp- 150-159.

Leydig, F., Lehrbuch der Histologie. 1857.

Leydig, F., Ueber die Nervenendigung in den sogenannten Schleimkanilen der
Fische and iiber entsprechende Organe der durch Kiemen athmenden Amphi-
bien, Arch. f. Anat. u. Physiol. 1861.

Leydig, F., Ueber die Organe eines sechsten Sinnes. Nov. act. acad. Leop. Carol,
1868. Vol. XXXIV, pp. 1-102.

Leydig, F., Ueber die allgemeinen Bedeckungen der Amphibien. Arch. f. mik.
Anat. 1875. Vol. XII, p. 119.

Leydig, F., Ueber die Schleichenlurche. Zeitsch. f. wiss. Zool. Vol, XVIII.

LITERATURE. 355

Leydig, F., Ueber die Schwanzflosse, Tastkérperchen und Endorgane der Nerven
bei Batrachiern. Arch. f. mik. Anat. 1876. Vol. XII, pp. 513-527.

Leydig, F., Die anuren Batrachier der deutschen Fauna. Bonn, 1877, p. 123.

Lister, J., On the cutaneous pigmentary system of the frog. Phil. Trans. 1857.
Vol. CXLVILII, p. 627.

Macallum, A. B.} The nerve terminations in the cutaneous epithelium of the tad-
pole. Quart. Journ. Micros. Sci. 1886. Vol. XXVI, p. 53.

Mayer, A., Ueber das Epithelium bei den Amphibien. Froriep’s Notizen, 1839.
Vol. EX, coll. 49-51.

Menke, Rana rubita, Linn. Zeitschr. Isis von Oken. 1827. Vol. XX, p. 172.

Merkel, Ueber die Endigungen der sensiblen Nerven in der Haut der Wirbelthiere.
Rostock, 1880.

Meyer, Ueber die Abhangigkeit der Gefasse und Pigmentzellen beim Frosch von
dem Nerveneinfluss. Virchow’s Arch. 1854. Vol. VI, p. 581.

Openchowski, T., Histologisches zur Innervation der Driisen. Pfifiger’s Arch.
1882. Vol. XXVII, pp. 223-232.

Pfitzner, W., Die Epidermis der Amphibien. Morph. Jahrb. 1880. Vol. VI,
p. 469.

Rainey, On the structure of the cutaneous follicles of the toad. ning Journ.
Micros. Sei. Vol. III, p. 257.

Roesel, Historia natur. rana. nostrat. Niirnberg, 1758, p. 3, ete.

Rudneff, Ueber die epidermiodale Schicht der Froschhaut. Arch, f. mik. Anat.
1865. Vol. I, p. 295.

Sattler, E. E., Die Verwendung des Lapisstiftes zur Untersuchung der Epithelien.
Arch. f. mik. Anat. 1882. Vol. XXI, p. 672.

Schneider, Historia amphibiorum. 1739.

Schultze, F. E., Epithel und Driisenzellen. Arch. f. mik. Anat. 1867. Vol. ITI,
P- 145-

Schulize, F. E., Ueber cuticulare Bildungen und Verhornung von Epithelzellen bei
den Wirbelthieren. Arch. f. mik. Anat. 1869. Vol. V, p. 295.

Schultze, M., Ueber die Nervenendigung in der Netzhaut des Auges bei Menschen
und Thieren. Centralbl. f. med. Wiss. 1869, p. 885.

Stieda, L., Ueber den Bau der Haut des Frosches. Arch. f. Anat. u. Physiol. 1865,
pp- 52-66.

Stricker, S., and Spina, A., Untersuchungen itiber die mechan. Leistungen d.
acinésen Driisen. Wiener med. Jahrb. 1880, p. 355; und Wiener Sitzungsb.
1880. (Skin and Membrana nictitans.)

Swammerdam, J., Biblia naturae. Vol. II, p. 808.

Szcesny, Beitriige zur Kenntniss der Textur der Froschhaut. Dissert.inaug. Dorpat,
1867.

Turner, Way in which toads shed their skins. Annals of Nat. History, 1850,
P- 430.

Wagner, R., Handworterbuch der Physiologie. Vol. III, p. 389.

Walter, Ueber die Driisen des Daumenballens des Froschmannchens. Verhandl. d.
naturf. Vereins der pr. Rheinlande und Westphalen. 1851, p. 331.

v. Wittich, Die griine Farbe der Haut unserer Frische, ete. Arch. f. Anat. u.

. Physiol. 1854, p. 41.

v. Wittich, Entgegnung auf Herm. Harless’s iiber die Chromatophoren des Frosches.

Arch. f. Anat. u. Physiol. 1854, p. 264.

356 THE SKIN AND THE SENSE-ORGANS.,

II. SPECIAL ORGANS OF TACTILE SENSATION,

a. The lateral sense-organs.

Beard, J., On the segmental sense-organs of the lateral line and on the morphology
of the vertebrate auditory organs. Zool. Anz. 1884. Vol. VII, p. 162.

Bugnion, E., Recherches sur les organes sensitifs qui se trouvent dans 1]’épiderme
du Protée et de ’Axolotl. Dissert. inaug. Ziirich. Tire du Boll. No. 7, de la
société vaucloise des Sc. nat. Vol. XII. Lausanne, 1873. Verhandl. d.
schweiz. naturforsch. Gesells. Ziirich, 1873. Vol. LVI, p. 49.

Froriep, A., Ueber Anlagen von Sinnesorganen am Facialis, Glossopharyngeus und
Vagus, Arch. f. Anat. u. Physiol. 1885.

Hoffmann, C. K., Bronn’s Klassen und Ordnungen des Thierreichs. Leipzig and
Heidelberg, 1873-1878.

v. Kélliker, A., Ueber neue Sinnesorgane von Froschlarven. Sitzungsb. Wtirzburg.
1885, p. 79.

Krause, W., Die Nervenendigung innerhalb der terminal Kérperchen. Arch. f.
mik, Anat. 1880. Vol. XIX, pp. 53-137.

Leydig, F., Ueber die Organe eines sechsten Sinnes. Nova acta Acad. Leopold. Carol.
Dresden, 1868. Vol. XXXIV, pp. 1-102.

Leydig, F., Ueber die allgemeinen Bedeckungen der Amphibien. Arch. f. mik.
Anat. 1875. Vol. XII, pp. 513-527.

Leydig, F., Ueber Tastkérperchen und Muskelstructur. Arch. f. Anat. u. Physiol.
1856, p. 150.

Malbranc, M., Bemerkung betreffend die Sinnesorgane der Seitenlinie der Amphi-
bien, Centralbl. f. med. Wiss. 1875, p. 5.

Malbrane, M., Von der Seitenlinie und ihren Sinnesorganen bei Amphibien.
Zeitsch. f. wiss. Zool. 1876. Vol. XX VI, pp. 24-86.

Schultze, E E., Ueber die Nervenendigung in den sogenannten Schleimkanilen
der Fische und iiber entsprechende Organe der durch Kiemen athmenden
Amphibien. Arch. f. Anat. u. Physiol. 1861, p. 759.

Schulize, F. E., Ueber die Sinnesorgane der Seitenlinie bei Fischen und Amphi-
bien. Arch, f. mik. Anat. 1870. Vol. VI, p. 62.

b. The touch-corpuscles of Golgi.

Golgi, C., Della terminazione dei nervi nei tendini e di un nuovo apparato nervoso
terminale musculo-tendineo. Atti della Societi Italiana di scienze naturali.
Milan, 1879. Vol. XXI; and abstracted in Centralbl. f. med. Wiss. 1879,
Pp. 725.

Golgi, C., Intorno alla distribuzione e terminazione dei nervi nei tendini dell’ uomo
e di altri vertebrali. Estratto dai Rendiconti del R. Istituto Lombardo. Serie
II. Vol. XI, Fasc. IX. Milan, 1878. Abstract in Centralbl. f. med. Wiss.
1879. Vol. 41, p. 725.

Liéwe, L., Ueber eine eigenthiimliche Art von Gelenknervenkérperchen beim
Frosch. Arch. f. mik. Anat. 1880. Vol. XVI, p. 613.

III. THE ORGANS OF TASTE.

Beale, L. 8., New observations upon the minute anatomy of the frog’s tongue. Phil.
Trans. 1865, p. 443.

Biedermann, W., Ueber morphologische Veriinderungen der Zungendriisen des
Frosches, ete. Wiener acad. Sitzungsb. 1882. Vol. LXXXVI, Pt. III, p. 67.

LITERATURE. 357

Billroth, T., Ueber die Epithelzellen der Froschzunge, etc. Arch. f. Anat. u.
Physiol. 1858, p. 159.

Engelmann, T. W., Ueber die Endigungsweise der Geschmacksnerven des Frosches.
Centralbl. f. med. Wiss. 1867, p. 785.

Engelmann, T. W., Ueber die Endigungen der Geschmacksnerven in der Zunge
des Frosches. Zeitsch. f. wiss. Zool. 1868. Vol. XVIII, p. 142.

Engelmann, T. W., Die Geschmacksorgane. Stricker’s Handbuch der Gewebelehre.
1872.

Fixsen, C., De linguae raninae structura. Dorpat, 1857.

Gottschau, M., Ueber Geschmacksorgane der Wirbelthiere. Biol. Centralbl. 1882,
pp- 240-248.

Hartmann, R., Ueber die Endigungsweise der Nerven in den Papillae fungiformes
der Frosehzunge. Arch. f. Anat. u. Physiol. 1863, p. 634.

Hoyer, Mikroskopische Untersuchungen iiber die Zunge des Frosches. Arch. f.
Anat. u. Physiol. 1859, p. 481.

Hoyer, Ueber die Epithelzellen der Froschzunge, ete. Arch. f. Anat. u. Physiol.
1858, p. 163; also in Deutscher Klinik, 1857. No. 21.

Hyrtl, Ueber abwickelbare Gefiasskniauel in der Zunge der Batrachier. Wiener
Acad. Sitzungsb. 1863. Vol. XLVIII, Pt. I, p. 437.

Key, E. A., Ueber die Endigungsweise des Geschmacksnerven in der Zunge des
Frosches. Arch. f. Anat. u. Physiol. 1861, p. 329.

Lépine (On the nerve supply of the glands of the tongue). Arbeiten aus d.
physiol. Anstalt zu Leipzig, 1870, p. 113.
Molin, R., Ueber die Theilung der Nervenprimitivréhren in den Papillae fungi-
formes der Froschzunge. Wiener acad. Sitzungsb. 1849. Vol. III, p. 183.
Schultze, F. E., Die Geschmacksorgane der Froschlarven. Arch. f. mik. Anat.
1870. Vol. VI, p. 407. ;

Waller, A., Minute structure of the organ of taste in vertebrate animals. Proc.
Roy. Soc. 1848. Vol. V, p. 751-

Waller, A., Minute structure of the papillae and nerves of the tongue of the frog
and toad. * Phil. Trans. 1848. Pt. I, p. 139.

Waller, A., Microscopic examination of some of the principal tissues of the tongue,
etc. Phil. Mag. 1847. Vol. XXX, p. 277.

IV. THE NOSE.

Babuchin, Das Geruchsorgan, in Stricker’s Handbuch der Gewebelehre. 1872,
p- 964.

de Blainville, M. H. M. Ducrotay, L’Organisation des animaux. Paris, 1822,
p- 328.

Blaue, J., Untersuchungen iiber den Bau der Nasenschleimhaut bei Fischen und
Amphibien, namentlich tiber Endknorpel als Endapparate des Nervus olfactorius.
Arch. f. mik. Anat. 1884. Vol. XXX, pp. 231-309. Zool. Anzeiger. Vol. V,
pp. 657-680.

Born, G., Ueber die Nasenhéhlen und den Thrinennasengang der Amphibien.
Morph. Jahrb. 1875. Vol. II, p. 4.

Born, G., Ueber die Nasenhéhlen und den Thrinennasengang der Amphibien.
Breslau. Habilit.-Schrift. 1877.

Born, G., Die Nasenhdhlen und der Thriinennasengang der amnioten Wirbelthiere.
Morph. Jahrb. 1879. Vol. V, p. 62. 1882. Vol. VIII, pp. 188-232.

v. Brunn, Die Membrana limitans olfactoria. Centralbl. f. med. Wiss. 1874,
Pp- 7°9-

v. Brunn, Untersuchungen iiber das Riechepithel. Arch. f. mik. Anat. 1875. Vol.
XI, pp. 468-478.

358 THE SKIN AND THE SENSE-ORGANS,

v. Brunn, Weitere Untersuchungen tiber das Riechepithel u. sein Verhalten zum
N. olfactorius. Arch. f. mik. Anat. 1880. Vol. XVII, p. 141.

Cisoff, Zur Kenntniss der Regio olfactoria. Centralbl. f. med. Wiss. 1874, pp.
689-691.

Cleott, Zur Frage iiber die Endigung der Riechnerven beim Frosche. Arbeiten
der naturf. Gesells. an der Universitit Kassan. 1879. Vol. VIII (in
Russian).

Clarke, J. Lockhart, Ueber den Bau des Bulbus olfactorius und der Geruchsschleim-
haut. Zeitsch. f. wiss. Zool. 1862. Vol. XI, p. 31.

Colossanti, Untersuchungen iiber die Durchschneidung des N. olfactorius bei
Fréschen. Arch. f. Anat. u. Physiol. 1875.

Dirkinck-Holmfield-Christmas, J., Experimentalle Underségelen Bijgningen.
Nordiskt medicinskt Arkiv., 1883. Vol. X XVI, pp. 50-60.

Dogiel, A., Ueber die Driisen der Nasenschleimhaut, besonders die Bowmanschen
Driisen, Arch. f. mik. Anat.

Dogiel, A., Ueber den Bau des Geruchsorgans bei Garroirren, Knochenfischen,
und Amphibien. Arch. f. mik. Anat, 1887. Vol. X XIX, p. 74.

Dogiel, A., Ueber den Bau des Geruchsorgans bei Fischen und Amphibien. Biol.
Centralbl. Vol. I, pp. 428-431.

Dogiel, A., Ueber die Driisen d. Regio olfactoria. Arch. f. mik. Anat..1885. Vol.
XXVI, p. 50. F

Ecker, E., Bericht iiber die Verhandl. der Gesellschaft fiir Beford. der Naturw. zu
Freiburg, 1855, p. 199; and in Zeitsch. f. wiss. Zool. 1856, Vol. VIII, p. 303.

Eckhard, C., Beitriige zur Anatomie und Physiologie. Pt. I, 1855, p. 77.

Eckhard, C., Ueber die Endigungsweise der Geruchsnerven. Beitrage zur Anat. u.
Physiol. Giessen, 1882. Vol. I, p. 77.

Erichsen, J., De textura nervi olfactorii ejusque ramorum. Dissert. inaug. 1857.

Exner, 8., Untersuchungen iiber die Riechschleimhaut des Frosches. Sitzungsb.
der Wiener Acad. 1871. Vol. LXIII, Pt. IT, p. 44.

Exner, S., Weitere Studien iiber die Structur der Riechschleimhaut bei Wirbel-
thieren. Sitzungsb. der Wiener Acad. 1872. Vol. LXV, Pt. ITI, p. 7.

Exner, 8., Fortgesetzte Studien tiber die Endigungsweise des Geruchsnerven.
Sitzungsb. der Wiener Acad. 1878. Vol. LX XVI, Pt. III, p. 171.

Gastaldi, Nuove. Ricerche sovra la terminazione del nervo olfatt. Mem. della
reale Acad. della scienze di Torino. 1858. Vol. XVII, Series IT, p. 369.

Hoffmann, Lehrbuch der Anatomie der Sinnesorgane.

Hoffmann, C. K., Ondersockingen over den anat. bouw van de membrana olfactoria
en het periph. uitiende van den Nervus olfactorius. Dissert. inaug. 1866.
Hoffmann, C. K., Amphibia in Bronn’s Klassen und Ordnungen des Thierreichs.

Leipzig und Heidelberg, 1873-1878. Vol. VI, pp. 335-347.

Horn, H., Ueber die Endschlingen des Geruchsnerven (nervus olfactorius) der Rana
temporaria. Arch. f. Anat. u. Physiol. 1850.

Hoyer, H., De tunica mucosa narium textura. Dissert. inaug. Berol., 1857.

Hoyer, H., Ueber die mikroskopischen Verhiltnisse der Nasenschleimhaut, etc.
Arch. f. Anat, u. Physiol. 1860, p. 50.

Langer, C., Ueber das Lymphgefisssystem des Frosches. Wiener Acad. Sitzungsb.
1867. Vol. LV, Pt. I, p. 615.

Legal, B., Die Nasenhthlen und der Thriinennasengang der aranioten Wirbelthiere.
Morph, Jahrb. 1882. Vol. VIII, p. 353.

Martin, Studies from the physiological laboratory in the University of Cambridge.
Pt. I. 1873.

Paschutin, V., Ueber den Bau der Schleimhaut der Regio olfactorio beim Frosch.
Medicinisky Wjestnik. 1872. Nos. 38-40.

Paschutin, V., Ueber den Bau der Schleimhaut der Regio olfactoria des Frosches.
Arbeiten aus d. phys. Laborat. Leipzig, 1873.

LITERATURE. 359

Paulsen, E., Ueber die Driisen der Nasenschleimhaut besonders die Bowman’schen
Driasen. Arch. f. mik. Anat. 1886. Vol. XXVI, pp. 307-321.

Piersol, G. A., Beitrage zur Histologie der Harderschen Driisen der Amphibien.
Arch. f. mik. Anat. 1887. Vol. X XTX, p. 594.

Reichert, B., Arch. f. Anat. u. Physiol. 1857, p. 39. Bericht.

Schultze, M., Ueber die Endigungsweise des Geruchsnerven und die Epithelial-
gebilde der N. hleimhaut. Monatsb. Acad. z. Berlin. 1856, p. 504.

Schultze, M., Untersuchungen iiber den Bau der Nasenschleimhaut, namentlich die
Structur und Endigungsweise der Geruchsnerven bei dem Menschen und den
Wirbelthieren. Halle, 1862. Vol. VII, pp. 32-41; also published it in’ Berlin,
1875. Abstract in Centralbl. f. med. Wiss. 1263, p. 97-

Seeberg, Disq. microsc. de textura membr. pitnit. nasi. Dorpat, 1855. Dissert.

inaug.

Stirling, W., and Macdonald, The minute structure of the palatine nerves of the
frog and the termination of nerves in blood- vessels and glands. Journ. of Anat.
and Physiol. 1884. Vol. XVII, p. 293.

Wiedersheim, R., Ueber die Kopfdriisen der Amphibien. Sitzungsb. d. phys.-med.
Gesell. in Wiirzburg, 1876. Febr. 5.

Wiedersheim, R., Die Kopfdriisen der geschwanzten Amphibien und die Glandula
intermaxillaris der Anuren. Zeitsch. f. wiss. Zool. 1876. Vol. XXVII,

. I-50.

Wiedersheim, R., Lehrbuch der vergl. Anatomie der Wirbelthiere. Pt. 1. Jena,

1882.

V. THE EAR.

Chatin, J., Recherches pour servir a histoire du noyau dans |’épithelin auditif
des batrachiens. Annales des sciences nat. Zool. 1883. Vol, XVI, Series VI,
Art. No. 2.

' Comparetti, A., in gymmnasio patavino observationes anatomicae de aure interna

comparatae. Patavii, 1789.

Crombie, J. M., On the membrana tympani. Journ. of Anat. and Physiol. 1883,
Pp- 523-536.

Cuvier, G., Lecons d’anatomie comparée. Paris, 1800. Vol. IL.

Deiters, O., Ueber das innere Gehérorgan der Amphibien. Arch. f, Anat. u. Physiol.
1862, p. 277.

Eberth, C. J., Zur Kenniniss der Verbreitung der glatten Muskelfasern (Tympanic
sectabrasie). Zeitsch. f. wiss. Zool. 1863. Vol. XII, p. 364.

Ferré, Etude sur la créte auditive chez les vertébrés. Ann. Sci. Nat. Bordeaux.
Vol. I, No. IIL

Hasse, C., Die Histologie des Bogenapparates und des Steinsacks der Frische.
Zeitsch. f. wiss. Zool. 1868. Vol. XVIII, p. 71.

Hasse, C., Das GehGrorgan der Frische. Zeitsch. f. wiss. Zool. 1868. Vol. XVIII,
P- 359-

— C., Das knécherne Labyrinth der Frische. Anatomische Studien, 2nd Pt.
1072, Pp. 377- 7

Hasse, C., Die vergleichende Morphologie und Histologie des hautigen Gehérorgans
der Wirbelthiere. Supplement to the Anatomische Studien. Vol. I, 1873-

Hasse, C., Die Lymphbahnen des inneren-Ohres der Wirbelthiere. In the Anato-
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Hasse, C., Das Gehérorgan der Wirbelthiere von Gustav Retzius. Arch. f. Ohren-
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Hoffmann, Lehrbuch der Anatomie der Sinnesorgane.

Hoffmann, Bronn’s Klassen und Ordnungen des Thierreichs. Leipzig and Heidel-
berg, 1873-1878. Vol. VI, pp. 304-335.

360 THE SKIN AND THE SENSE-ORGANS.

Ibsen, J., Anatomiske Undersigelser over orets Labyrinth. Udgivet vet P. L.
Panum. Kjébenhawn, 1846 (abstract in Virchow and Hirsch’sJahresb. 1881,p. 88).

Kuhn, Ueber das hiutige Labyrinth der Amphibien, Arch. f. mik. Anat. 1880.
Vol. XVII, pp. 479-550.

Kuhn, Zur Anatomie des inneren Ohres der Wirbelthiere. Compt. Tend. du III
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Leydig, F., Lehrbuch der Histologie des Menschen und der Thiere. Frankfurt a.
M. 1857.

Leydig, F., Ueber neuere den Aquaeductus vestibuli des Menschen und der Thiere
betreffende Forschungen. Sitzungsb. d. Niederrheinischen naturf. Gesellsch. in
Bonn, 1874. Vol. XXXIV, p. 124.

Moldenhauer, Vergleichende Histologie des Trommelfells, Arch. f. Ohrenheilk.
1878, p. I.

Pappenheim, 8., Ueber Verbreitung der Flimmerbewegung. Arch. f. Anat. u.
Physiol. 1840, p. 533.

Retzius, G., On hérselnervens indningssiitt i maculae och cristae acusticae. Nor-
diskt medicinskt arkiv. 1871. Vol. ITI.

Retzius, G., Zur Kenntniss der Morphologie des inneren Ohres bei Wirbelthieren.
Nord. Med. Ark. 1880. Vol. XII, No. r2.

Retzius, G., Zur Kenntniss des Gehororgans der Wirbelthiere. Arch. f. Anat. u.
Physiol. 1880, pp. 235-244.

Retzius, G., Das Gehérorgan der Wirbelthiere. Pts. I and II, 1881. Stockholm.

Retzius, G., Das Gehdrorgan der Wirbelthiere. Congr. internat. de Copenhagen.
Anatomy, p. 29.

Retzius, G., Das Gehérorgan der Fische und Amphibien. Pt. I, 1881. Stockholm.

Retzius, G., Zur Kenntniss der Morphologie des inneren Ohres bei Wirbelthieren.
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Retzius, G., Ueber die peripherische Endigungsweise der Gehérnerven. Biol.
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Schultze, F. E., Zur Kenntniss der Endigungsweise der Hérnerven bei Fischen und
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Waldeyer, W., Hirnerv und Schnecke. Stricker’s Handbuch der Gewebelehre,
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Windischmann, De penitiori auris in amphibiis structura Lipsiae, 1831.

VI. THE EYE.

a. The cornea and sclerotic.

Angelucci, A., Ueber den Bau u. die Entwickelung des vorderen Uvealtractus der
Vertebraten. Centralbl. f. d. med. Wiss. 1879. No. 24, p. 417.

Altmann, R., Ueber die Verwerthbarkeit der Corrosion in der mikroskopischen
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Arnold, J., Die Vorgiinge bei der Regeneration epithelialer Gebilde. Virchow’s
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Arnold, J., Experimentale Untersuchungen iiber die Entwicklung der Blutcapil-
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4
7

- LITERATURE. 361

Boddaert, Zur Histologie der Cornea. Centralbl. f. med. Wiss. 1871, p. 337-

Ciaccio, J. V., On the nerves of the cornea and of their distribution in the corneal
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Clasow, E., Om corneal epithel. Upsala likareforenings forhandlingar. 1869. Vol.
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Cohnheim, J., Ueber die Endigung der sensiblen Nerven in der Hornhaut. Vir-
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Durante, F., Sulla terminazione dei nervi della cornea. Richerche fatte nel laborat.
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Engelmann, T. V., Ueber die Hornhaut des Auges. Leipzig, 1867.

v. Ewetsky, Ueber das Endothel der Membrana Descemeti. Untersuch. aus d.
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Frey, H., Handbuch der Histologie und Histochemie.

Generisch, Zur Lehre von den Saftkanalchen in der Cornea. Med. Jahrb. der
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Guye, A. G., Over bekercellen en in het byzonder over de bekercellen in de mem-
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Hansen, A., Untersuchungen iiber die entziindlichen Veranderungen der Hornhaut-
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Harpeck, C., Ueber die Bedeutung der nach Silberimpragnation auftretenden
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Hartmann, R., Ueber die durch den Gebrauch der Héllensteinlésung kiinstlich ©
dargestellten Lymphgefassanhainge, Saftcanalchen und epithelahnlichen Bil-

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Heiberg, H., Ueber die Neubildung des Hornhaut-Epithels. Wiener Med. Jahrb.
1871.

Heisrath, F., Ueber d. Zusammenhang d. vordern Augenkammer mit d. vord. Ciliar-
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Helfreich, Ueber die Nerven der Conjunctiva und Sclera. Wiirzburg, 1370.

Henle, J., Handbuch der systematischen Anatomie, 1866. Vol. IT.

His, W., Untersuchungen iiber der Bau der Hornhaut, in Verhandlungen der phys.-
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His, W., Ueber die Einwirkung des salpetersauren Silberoxydes auf die Hornhaut.
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Hoffmann, F. A., Ueber Contractilitatsvorgiinge im vorderen Epithel der Frosch-
hornhaut. Diss. Berlin, 1868.

Hoffmann, F. A., Epithelneubildung auf der Cornea. Virchow’s Arch. 1870.
Vol. LI, p. 373.

Hosch, F., Ueber die angebliche Contractilitat der Knorpelzellen und Hornhaut-
kérperchen. Pfliiger’s Arch. f. d. ges. Physiol. 1873. Vol. VI, p. 515.

Hoyer, H., Ueber den Austritt von Nervenfasern in das Epithel der Hornhaut.
Arch. f. Anat. u. Physiol. 1866, pp. 180-195.

Hoyer, H., Ueber die Nerven der Hornhaut. Arch. f. mik.Anat.1873. Vol. IX, p. 220.

a E., Das Epithel der hintern Hornhautfliche. Centralbl. f. d. med. Wiss.
1904, p- 513.

Klein, E., Some remarks on the finer nerves of the cornea. Monthly Journ. Micros.
Sci. 1872. Vol. VII, pp. 156-164.

Klein, E., Beitrage zur Kenntniss der peripherischen Verzweigung markloser Ner-
venfasern. Centralbl. f. d. med. Wiss. 1871, p. 594-

Klemensiewiez, R., Karyokinese in den fixen Hornhautzellen bei Entziindung.
Centralbl. f. d. anil Wiss. 1884, p. 163.

v. Kélliker, A., Ueber die Nerven der Hornhaut. Mittheilungen der naturforschenden
Gesellschaft in Ziirich. 1849.

362 THE SKIN AND THE SENSE-ORGANS.

v. Kélliker, A., Ueber die Nervenendigungen in der Hornhaut. Wirzb. naturw.
Zeitschr. 1866. Vol. VI, p. 121.

Kénigstein, L., Histologische Notizen. Arch. f. Ophthalmologie. 1881. Vol.
XXVII, p. 56.

Kénigstein, L., Beobachtungen iiber die Nerven der Cornea und ihre Gefasse.
Wiener Sitzungsber. 1877. Vol. LXXVI, Pt. III, p. 17.

Kénigstein, L., Beobachtungen iiber die Nerven der Cornea und ihre Gefasse.
Wiener Sitzungsber. 1877. Vol. LX XVI, Pt. III, p. 37.

Krause, W., Ueber das vordere Epithel der Cornea. Gittinger Nachrichten, 1870.
Arch. f. Anat. u. Physiol. 1870.

Krause, W., Anatomischer Jahresbericht fiir 1871 in Prager Vierteljahrsschrift.

Kihne, W., Untersuchungen iiber Protoplasma und die Contractilitét. 1864.

Lavdowsky, M., Das Saugadersystem und die Nerven der Cornea. Arch. f. mik.
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Leber, T., Zur Kenntniss der Imprignationsmethoden der Hornhaut und ahnlicher
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Leydig, F., Lehrbuch der Histologie. 1857.

Lightbody, W. H., Observations on the comparative anatomy of the cornea of
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Lipmann, H., Ueber die Endigung der Nerven im eigentlichen Gewebe und im
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Robinski, Die Kittsubstanz auf Reaction des Argentum nitricum. Arch. f. Anat.
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Rollett, A., Ueber das Gefiige der Substantia propria corneae. Sitzungsb. Wiener
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Saemisch, T., Beitrage zur normalen und pathologischen Anatomie des Auges
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Sattler, E. E., Die Verwendung des Lapisstiftes sar Untersuchung der Epithelien.
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Schalygen, C., Ueber Hornhautepithel und besonders iiber Vermehrung der Zellen
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Schweigger, Ueber den Bau der Hornhaut, Allg. med. Centralzeitung. Berlin,
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re ee

ee

anh”

,

LITERATURE. 363

Stricker, 8., Conjunctiva und Sclerotica im Handb. der Lehre von den Geweben des
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Swaen, M. A., Des éléments cellulaires et des canaux plastiques dans la cornée de
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Wolff, W., Die Nerven der Cornea. Arch. f. mik. Anat. 1882. Vol. XX, p. 373-

Zielonko, J., Ueber die Entwicklung und Proliferation von Epithelien und Endo-
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b. The lens, choroid, iris, appendages, axterior and
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2 ES BR., Ueber Corrosion in der Histologie. Centralbl. f. d. med. Wiss. 1878,
Pp. 245-

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Angelucci, A., Ueber den Bau und die Entwickeluny des vorderen Uveatractus der
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Arnold, Die Linse. Handbuch der gesammten Augenheilkunde. 1874.

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Becker, Untersuchungen tiber den Bau der Linse bei dem Menschen und den Wir-
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Bubuchin, Die Linse. In Stricker’s Handb. der Gewebelehre. 1872.

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364 THE SKIN AND THE SENSE-ORGANS.

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Koganei, J., Untersuchungen tiber den Bau der Iris. Sitzungsber. d, Acad. d. Wiss.
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v. Kélliker, A., Handbuch der Gewebelehre. 1867.

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Leydig, F., Anatomisch-histologische Untersuchungen tiber Fische und Reptilien,
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Robinski, 8., Zur Anatomie, Physiologie und Pathologie der Augenlinse des
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Sattler, E. E., Die Verwendung des Lapisstiftes za Untersuchungen der Epithelien.
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Stricker, S., Untersuchungen iiber die capillaren Blutgefisse in der Nickhaut des
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Stricker, S., Untersuchungen iiber die mechan. Leistungen d. acirrésen Drtiest:,
Wiener mal Jahrb. 1880, p. 355; also Wiener Sitzungsb. 1880 (Membrana
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P- 237- .

Stricker, S., Studien tiber den Bau und das Leben der: capillaren Blutgefisse.
Wiener Sitzungsb. 1866. Vol. LII, Pt. II, p. 379.

Siricker, S., Untersuchungen iiber die capillaren Blutgefisse in der Nickhaut des
Frosches. Moleschott’s Untersuchungen. 1870, Vol. X, p. 168.

Thin, G., Contribution to the anatomy of the lens. Journ. of Anat. and Physiol.
1876, Vol. X, p. 223.

Valentin, Handbuch der Physiologie v. Wagner. 1842.

Virchow, H., Ueber die Gefiisse im Auge und in der Umgebung des Auges beim
Frosche. Zeit. f. wiss. Zool. 1881. Vol. XXXV, pp. 247-281.

Virchow, H., Ueber die Gefiisse des Kopfes und des Auges des Frosches, Verhandl.
Wirzburg. 1881. Vol. XV, p. xxxiv.

Virchow, H., Mittheilungen zur vergleichenden Anatomie des Wirbelthierauges.
Versamml, deutsch, Naturf. und Aerzte. Strassburg. 1885, pp. 409, 410,
Virchow, H., Ueber den ciliaren Muskel des Frosches. Verhandl. d. physiol.

Gesell. zu Berlin, 1885, p. 571.

Virchow, H., Ueber die verschiedenen Formen des Ligamentum pectinatum iridis.
Versamml, d, Naturf. und Aerzte. 1885, p. 409.

Zimmermann, W., Ueber circumvasale Saftriiume der Glaskérpergefiisse von Rana
esculenta. Arch. f, mik, Anat. 1886. Vol. XX VII, p. 410.

|

LITERATURE. — 365

c. The retina.

Babuchin, Vergleichende histologische Studien. Wiirzburger naturwissensch. Zeitsch.
1864. Vol. V, p. 127.

Beauregard, M. H., Contribution & l'étude du rouge rétinien. Journ. de l’anat. et
de la physiol. 1879. Vol. XV, p. 161.

Boll, F., Zur Anatomie und Physiologie der Retina. Berlin. Acad. Monatsber.
“1876, p. 783-

Dennissenko, G., Vorlaufige Bemerkungen zur Lehre iiber den Bau der Netzhaut.
Mitt. aus dake embryolog. Institut. d. Wiener Universitat, 1850, Vol. II, p. 1;
Abstract in Centralbl. f. d. med. Wiss. 1880, p. 739.

Dennissenko, G., Ueber den Bau der ausseren Kérnerschicht der Netzhaut bei den
Wirbelthieren. Arch. f. mik. Anat. 1881. Vol. XIX, p. 395.

Dietl, M. J., Beitrag zur Kenntniss des feineren Baues der Stabchenaussenglieder
in der Netzhaut des Frosches. Arch. f. Augen- u. Ohrenheilkunde. 1878. Vol.
VII, pp. 17-24.

Dobrowolsky, Die Doppelzapfen. Arch. f. Anat. u. Physiol. 1871.

Dobrowolsky, Zur Anatomie der Retina. Arch. f. Anat. u. Physiol. 1871.

Ewart, J. C., Notes on the minute structure of the retina and vitreous humour.
Journ. of Anat. and Physiol. 1875. Vol. TX.

Ewart, J. C., and Thin, G., On the structure of the retina. Journ. of Anat. and
Physiol. 1876. Vol. IX, p. 166.

Frisch, Gestalten des Choroidalpigments. Wiener Sitzungsber. 1868. Vol. LVIII,
pp- 316-320.

Heinemann, C., Beitrage zur Anatomie der Retina. Arch. f. mik. Anat. 1877.
Vol. XIV, p. 409.

Helfreich, Ophthalmoscopische Mittheilungen tiber den Purpur der Retina. Cen-
tralbl. f. d. med. Wiss. 1877, p. 113.

Henle-and Merkel, Ueber die sogenannte Bindesubstanz der Centralorgane des
Nervensystems. Zeitsch. f. rat. Med. 3rd Series, 1869. Vol. XXXIV.

Hensen, Ueber das Sehen in der Fovea centralis. Virchow’s Arch. 1867. Vol.
XXXIX, p. 75.

Hoffmann, Lehrbuch der Anatomie der Sinnesorgane.

Hoffmann, Bronn’s Thierbuch. Leipzig and Heidelberg, 1873-1878. Vol. VI,
Pp- 274-297-

Hulke, J. W., A contribution to the anatomy of the amphibian and reptilian

~ retina. Quart. Journ. Micros. Sci. 1864, Vol. IV, p. 236; and London Ophthal-
mic Hospital Reports, 1864.

Hulke, J. W., On the retina of amphibia and reptiles. Journ. of Anat. and Physiol.
1867. Vol. I, p. 94.

Kihne, W., Ueber den Sehpurpur. Centralbl. f. d. med. Wiss. 1877, p. 193.

Kiuhne, W., Fortgesetzte Untersuchungen iiber die Retina und die Pigmente des
Auges. Heidelberger physiol. Untersuch. 1878, Vol. II, p. 89; Abstract in
Centralbl. f. d. med. Wiss. 1879, p. 276.

v. Kélliker, A., Zur Anatomie und Physiologie der Retina, Verhandl. d. phys.-med.
Gesellsch. Wiirzburg, 1852. Vol. III, p. 316.

v. Kdélliker, A., Microscopische Anatomie. 1854. Vol. IT.

v. Kélliker, re Handbuch der Gewebelehre. 1867.

Krause, W., Die Nervenendigung in der Retina. Arch. f. mik. Anat. 1876. Vol.
XII, pp. 742-790.

Krause, W., Die Nervenendigung innerhalb der Copmninghen Kérperchen. Arch. f.
mik. Anat. 1881. Vol. XIX, p. 53.

Landolt, Beitrag zur Anatomie der Retina vom Frosch, Salamander und Triton.
Arch. f. mik. Anat. 1871. Vol. VII, p. 81.

366 THE SKIN AND THE SENSE-ORGANS.

Leydig, F., Anatomisch-histologische Untersuchungen tiber Fische und Reptilien.
1853.

Leydig, F., Die Farbe der Retina und das Leuchten der Augen. Arch. f.
Naturgesch. 1877. Vol. X XXIII, p. 8.

Manz, W., Ueber den Bau der Retina des Frosches. Zeitsch. f. rat. Med. 3rd Series,
1861. Vol. X, pp. 301-322.

Manz, W., Die Ganglienzellen der Froschnetzhaut. Zeitsch. f.rat. Med. 3rd Series,
1866. Vol. XXVIII.

Merkel, Zur Kenntniss der Stiibchenschicht der Retina. Arch. f. Anat. u. Physiol.
1870, p. 642.

Morano, F., Die Pigmentschicht der Retina. Arch. f. mik.:Anat. 1872. Vol.
VITII, p. 81.

Morano, F., Stomata in der Pigmentschicht der Retina. Centralbl. f. d. med. Wiss.
187 5, p- 67.

Miller, H., Histologie der Netzhaut. Zeitsch. f. wiss. Zool. 1851-52. Vol. ITI,
P- 234-

Miller, H., Ueber sternformige Zellen der Retina. Wiirzb. Verhandl. 1852. Vol.
II, pp. 216-218.

Miller, H., Ueber einige Verhiltnisse der Netzhaut bei Menschen und Thieren.
Wiirzb. Verhandl. 1853. Vol. IV, p. 96.

Miller, H., and Kélliker, A., Retina-Tafel. Plate X1X in Ecker’s Icones Physiol.
Linea, 1854.

Miller, H., Observations sur la structure de la rétine de certains animaux. Compt.
rend. 1856, Vol. XLITI, p. 743; and Annales hist. nat. 1856, Vol. XVIII,
Pp. 492.

Miller, H., Anatomisch-physiologische Untersuchungen iiber die Retina des Men-
schen und der Wirbelthiere. Zeitsch. f. wiss. Zool. 1857. Vol. VIII, p. 27.

Miller, W., Ueber die Stammentwicklung des Sehorgans der Wirbelthiere.
Leipzig, 1874, Festgabe an Carl Ludwig; Abstract in Centralbl. f. d. med. Wiss.
1877, pp. 372 and 388.

Ogneff, J., Histogenese der Retina. Centralbl. f. d. med. Wiss. 1881, p. 641.

Ogneff, J., Ueber die moleculire Schicht und die sogenannte reticulire Substanz
der Retina. Centralbl. f. d. med. Wiss. 1883, p. 801.

Oppenheimer, L. S., Die Stabchen in der Netzhaut der Hroshembr yuna, Schenk’ 8
Embryol. Mitt. Wien: 1878, p. 163.

Ranvier, L., Traité technique d’histologie, sixitme fasicule. 1882.

Ritter, Ueber den Bau der Stiibchen und fusseren Endigungen der Radialfasern an
der Netzhaut des Frosches. Arch. f. Ophthalmol. 1859.

Ritter, Zur Histologie des Auges. Arch. f. Ophthalmol. 1868. Vol. XI.

Schifferdecker, Studien zur vergleichenden Histologie der Retina. Arch. f. mik.
Anat, 1886. Vol. XXVIII, p. 305.

Schultze, M., Zur Anatomie und Physiologie der Retina. Arch. f. mik. Anat. 1866.
Vol. II, pp. 175-286.

Schultze, M., Ueber Staébchen und Zapfen der Retina. Arch. f. mik. Anat. 1867.
Vol. ITI, p. 215.

Schultze, M., Bemerkungen zu dem Aufsatze des Dr. W. Steinlin. Arch. f. mik.
Anat, 1868. Vol. IV, pp. 10-21.

Schultze, M., Die Retina. Stricker’s Handbuch der Gewebelehre. 1871.

Schultze, M., Ueber die Nervenendigung in der Netzhaut des Auges bei Menschen
und bei Thieren. Arch. f. mik. Anat. 1869. Vol. V, p. 380.

Schwalbe, Lehrbuch der Anatomie der Sinnesorgane. Erlangen, 1885, p. 392, ete.

Steinlin, W., Zur Anatomie und Physiologie der Retina. Arch. f. mik. Anat. 1868.
Vol. IV, p. To.

ee
=

THE SKIN AND THE SENSE-ORGANS.

I THE SKIN AND ITS APPENDAGES.

Tue general characters and the colouring of the skin have already
been described (pp. 4 to 7). The skin consists of the eutis vera or

_ corium, and the cuticle or epidermis, and Fig. 228.

is possessed of numerous glands.

a. The epidermis (Figs. 228, 230) con-
sists of several layers of epithelial cells,
those of the deepest layer being more or
less columnar in form, those of the middle
layer shorter and polygonal, while those of
the superficial layer are flattened, very =~ (a
transparent, and horny. ‘. Vertical section through the epi-

All the surfaces of these cells are serrated, See aie Rear ae
the serrations being, however, with diffi-” = 600 a
culty seen on the free surface of the super- ip rua

ficial cells (Leydig). Each cell has a C Deep layer.

D Isolated mucous-cells.

distinct nucleus; in the deeper cells the
nucleus is oval, broad, and rounded, in the superficial cells flattened
and thin.

The surface of the epidermis (Fig. 230) forms a very beautiful
mosaic of flat cells, chiefly hexagonal in form, with pale, cen-
tral, oval nuclei. Here and there two adjacent cells appear to
enclose a semilunar space (Fig. 228 D); these spaces are occupied
by peculiar cells (goblet-cells, E. Schultze; mucous cells, Leydig),
which do not belong to the superficial cells but the layer of cells
immediately beneath the horny layer (Schultze, Pfitzner). The
cells are rounded or flask-shaped, and closely resemble the epithelial
goblet-cells or chalice-cells. According to Rudneff they open on

the free surface by stomata; this is, however, denied by Schultze
and others.

368 THE SKIN AND THE SENSE-ORGANS.

According to Pfitzner these cells secrete a substance, which has

Fig. 229.

Vertical section through the skin of the back ; after Wiedersheim.

Co Superficial layer of cutis. Ep Epidermis.
Col Middle layer of cutis. H Horny layer of epidermis.

Co2 Deep layer of cutis. P_ Pigment-cells.
D ‘Cutaneous glands. W Papillae.
D1 Ducts of cutaneous glands.
an important function in connection with the process of casting the

skin, which consists in the separation of the upper layer from that

Fig. 231.

Surface view of epidermis of Rana temporaria ; Nerve terminations in the branched pigment-cells

after Eberth. of the cutis ; after Ehrmann, Hartnack, Obj.
A Epidermal cell, #, O3:
B Stoma-cell. I. Pigment ceasing abruptly at junction of
C Attached cuticle from duct of gland, nerve,

D Protoplasm and nucleus of stoma-cell. II, Pigment gradually ceasing along the nerve.

below brings about a complete shedding of the skin (Wiedersheim).

ae. -—

THE SKIN AND ITS APPENDAGES. 369

[The horny layer is, for the most part, very thin, as it consists of
one or two layers of flattened cells only (Schultze), but in some
situations, as on the back and especially on the under surface of the
toes, it is much thickened, and is then rough.

Deeply pigmented, branched cells, capable of contractile move-
ments, are also found, somewhat sparsely distributed, in the epi-
dermis (Leydig, H. Miller, Schultze). ]

b. The cutis (Fig. 229, Co, Co', Co*). The epidermis is generally
attached to the corium by means of a continuous layer of branched
cells, which is deeply stained when the animals are fed with
madder (Katschenko). Many of these cells are pigmented. This
layer is seldom flat, but is raised into papillae and folds, which are
repeated by the superimposed epidermis. In addition to this layer
the corium has, except in the webs and supplemental toes, three
distinct layers of connective-tissue, together with much unstriped

muscle-fibre (Eberth).

The superficial layer (Fig. 229 Co) is a loosely-meshed, much
pigmented, vascular layer; it forms a loose support for the nu-
merous glands, and is traversed by numerous nerves.

The middle layer (Co!) forms the groundwork of the cutis; it
is much firmer and more compact than the superficial layer ; in
section it appears as a broad band, bounded superficially by a sharp
line. It is chiefly composed of closely packed connective-tissue
fibres, which have, for the main part, a horizontal or wavy course ;
at certain points, however, vertical fibres are seen passing towards
the surface and hiding the sharp contour (between Co and Co'). At
such points the two sets of fibres form a sort of basket-work
arrangement.

The deepest layer (Fig. 229 Co”) is composed of very delicate,
white and yellow elastic fibres, and vessels and nerves ; it attaches
the whole integument to the underlying organs. By the looseness
of its structure it forms an important lymph-space.

[The musele-fibre of the cutis is very unevenly distributed. It is
found somewhat freely in the region of the back, the dorsal surface
of the head, and the neck ; less freely on the dorsal surfaces of the
extremities, very sparsely on the abdomen, breast, and ventral sur-
faces of the extremities; in the feet it appears to be absent
(Eberth).

The pigment of theskin. As already mentioned pigmented cells

Bb

370 THE SKIN AND THE SENSE-ORGANS.

occur in the epidermis, but by far the greater quantity of the cuta-
neous pigment is found in the cutis, and more especially in the
loose layer of branched cells, which form the boundary between
epidermis and true cutis. These cells, known as chromatophore-
cells, have been carefully investigated by Harless. They play an
extremely important part in bringing about the well-known
changes in the colouring of the skin. Bimmerman has proved
that these cells are influenced by stimulation of the nerves
supplying the region in which they occur. Ehrmann has been
able to trace a direct connection between the nerve-fibres and
the pigment-cells (Fig. 231 I, IJ). In such cases the pigment was
sometimes sharply marked off, at others was gradually lost along -
the nerve. |

ce, The papillae and ridges of the skin are classified by Leydig
as follows: (1) Small ridges, (2) larger ridges, (3) papillae with
touch-bodies, (4) papillae without touch-bodies, (5) papillae with the
ducts of glands, (6) capillaries in the form of papillae, (7) small
elevations, including the lateral organs.

[All these structures are derived from the cutis, the epithelium
above simply repeating the elevation, and being itself either not
increased in thickness or only to a slight degree. (For further
description of some of these papillae, see Organs of Tactile Sensation,
p. 380.)

Peculiar wart-like papillae are found on the articulations of the
first phalanges with the metatarsus, on the same articulations and
on the articulations between the first and second phalanges of the
third and fifth toes, and on the articulations between the first,
second, and third phalanges of the fourth toe. These papillae are
connected with the long flexor tendons by fine tendinous bands
(Klein).

Temporary papillae are developed in the females of Rana temporaria during the
breeding season ; according to O. Huber (J. e.), who has described them, their distri-
bution and structure is as follows :—

During the breeding season the skin of the sides of the trunk of female specimens
of Rana temporaria is rough; the small elevations, to which this roughness is due,
are each about the size of the head of a pin, and have the appearance of small,
rounded, white or pale rose-coloured, warty growths. The papillae reach their
greatest development and are most numerous on the sides of the trunk (Fig. 232 TD) ;
they may be traced on to the tympanic membrane, where they are arranged in a ring,
and in some cases under the eyes to the sides of the snout.

Anteriorly the papillae are absent from the median portion of the dorsal surface of
the trunk, but posteriorly, behind a line joining the anterior extremities of the two
iliac bones, the papillae cover the whole surface.

ay

THE SKIN AND ITS APPENDAGES. 371

The papillae are large and very numerous around the arms, and pass by gradual,
transitionary stages into the ordinary papillae of the region. Further they may be
traced backwards along the anterior or extensor surface of the thigh, the upper surface

Fig. 232.

IL Diagram to show the distribution of the temporary papillae in Rana %
temporaria ; after Huber. J Gi
If, HL Vertical sections through a temporary papilla ; after Huber.

of the leg, foot, and fifth toe. Occasionally a few papillae were found on flexor sur-
faces of the third and fourth metatarsus, and very rarely were any discovered on the
fore-limbs. They occur in no other batrachian of Germany (Huber).

Each papilla (Fig. 232 II and III) consists of a hemispherical elevation of the
cutis, and is covered either by a layer of normal epidermis or in some very rare cases
the epidermis was slightly thickened. The papilla consists of a firm connective-tissue
stroma, and is from 0°2-0'4 mm. in height, o-4-0°5 mm. broad (after hardening in
alcohol). Such glands as exist in the papilla usually open laterally (Fig. 232 IIT),
and the blood-vessels are numerous.

Bb2

372 THE SKIN AND THE SENSE-ORGANS.

The epidermis covering the papilla is well supplied with nerve-fibres, derived from
large ganglion-cells in the papilla (Fig. 232 III). The branched pigment-cells, so
numerous in the rest of the skin, are absent from the upper parts of the papillae
(Fig. 232 Il); the pigment-cells may cease either abruptly or gradually.

The rose-colour of the papillae is due to the presence of a golden red pigment.
After the breeding season the papillae are gradually lost, and the pigment-cells
wander into the unoccupied parts.

Huber compares the arrangement of the nerves to that of the ‘ touch-spots’ of
Merkel.

d. The glands of the skin are of two kinds, serous and mucous ;
they have been fully described by Engelmann and Openchowski.

(1) The serous glands (Kérnerdriisen, Engelmann) are large,
averaging in diameter 0°2—0'4 mm., but others vary in size from
o°13-0°8 mm. in diameter. They are found chiefly on the dorsum
of the trunk and arranged in groups, which vary in dimensions
from 3-20 mm. in length and 2-4 mm. in breadth. They may be
found in any part between the ear-region and the anus, on the
dorsal surface of the thigh, especially towards the outer and inner
borders. _ They are found very sparsely distributed on the ventral
surface of the trunk and on other parts of the extremities, though
as a rule a few are found on the dorsal surface of the feet and near
the phalanges. They are wanting in the nictitating membrane.

The glands have a rounded form, with the ducts placed at their
superficial poles. The glands possess three coats; externally is a
coat of connective-tissue, the fibres of which are arranged closely
together, and cross one another at acute angles: these fibres are con-
tinuous with the connective-tissue of the surrounding cutis. Inside
this coat is a thick layer of muscle-fibre (0°005-0°015 mm.); the
muscle-cells are arranged meridionally, with the one pole towards
the superficial surface of the gland, the other pole at the deep surface
(Hensche). Many of the fibres, however, extend only one-fourth or
one-third of this distance.

The innermost coat is a simple layer of epithelial cells, which
rests directly on the muscle-layer ; no basement-membrane or space
of any kind having been discovered between the two layers. When
examined in the recent state these cells are conical or cylindrical in
shape, and have the appearance of goblet-cells: they possess a
delicate but distinct cell-wall, but are open towards the lumen of the
gland. One or sometimes two rounded nuclei are found towards
the base of the gland, and surrounded by a small amount of gran-
ular protoplasm ; the rest of the cell is occupied by a mass of small,
rounded, highly refractive granules of about 0-002—0'01 mm. in

ae

‘wh

THE SKIN AND ITS APPENDAGES. 373

diameter. These granules are also to be found in the protoplasm of
the cell ; they contain a substance capable of swelling freely, and
present many points of resemblance to the granules found in the
cells of the oviducts.

These glands represent the poison-glands or lateral glands of toads, and the ear-
glands or parotids of Caecilia (Leydig). According to Leroux}, Gratiolet and Cloéz’,
the reaction of these glands in toads varies; according to du Bois-Reymond® the
reaction is, in frogs, acid; Engelmann‘ found the reaction of these glands, in frogs,
to be neutral, frequently, however, with a tendency to either acidity or alkalinity.

These glands correspond with the ‘large glands’ of Hensche, the ‘ contractile
glands’ of Stieda, the ‘large, dark glands’ of Eberth, and the ‘large contractile
glands’ of Leydig’s earlier publications.

(2) The mucous glands are, as a rule, smaller, more numerous,
and more evenly distributed than the serous glands. Usually they
lie in such close proximity as almost to touch one another ; according
to Engelmann an average number of sixty is found in one square
millimeter ; on the abdomen 62-68 ; flexor surfaces of the posterior
extremities in some’ places 76, but in others only 30—40 ; on the webs
only 2-6 to the square millimeter. On the nictitating membrane
they are arranged in two or three parallel rows, are large, and closely
applied to each other. They are wanting on the deeper surface of
the nictitating membrane.

The glands are generally rounded in faein and have a short neck
(Fig. 229). Glands in the recent condition, and not fully con-
tracted, have a diameter of o-06—-0'21 mm., the majority measure
0°12-0°16 mm. in diameter. The upper pole of the gland is usually

placed directly under the boundary between epidermis and cutis,

and, as a rule, about o°0o6—o'1 mm. beneath the superficial surface
of the skin. The duct usually passes directly to the surface, in a
straight line.

The structure of the glands corresponds, in general, with that of
the serous glands. Externally is a coat of connective-tissue, which
is, however, more firmly attached to the muscular coat than in the
ease of the serous glands, and may easily be mistaken for a struc-
tureless basement-membrane ° (Eberth). The museular coat is very
thin, and consists of 16-20 flat, spindle-shaped fibres; extending
from the upper to the lower pole as in the serous glands. Ata

+ Journal de Médicine, Vol. XI, p. 75.

* Comptes rendus, 1851, Vol. XXXII, p. 582.

* Untersuchungen tiber thier. Electricitat, 1830, Vol. I, p. 17.
* Arch. f. d. ges. Physiol., 1852, Vol. V, p. 505.

> Openchowski (/, c.) describes a basement-membrane.

374 THE SKIN AND THE SENSE-ORGANS.,

short distance (0'015-0'022 mm.) from the upper or superficial
pole each fibre has an ellipsoid thickening, composed of granular
protoplasm, and containing a clear oval nucleus.

The inner coat is composed of a single layer of epithelium, placed
directly on the muscular coat. The epithelium has a thickness of
about o°o1-0'02 mm.; it is, however, usually thicker towards the
base than towards the duct. The boundaries between the cells are
very indistinct, and so give the epithelium the appearance of a con-
tinuous layer of protoplasm. The glandular epithelium is not
directly continuous with the epithelium of the duct.

The shape of the cells depends upon their physiological condition.
Ina state of semi-contraction of the gland, the cells are cubical, and
their free borders pushed into the lumen in a slight convexity ;
when the gland is fully distended the cells are two or three times as
broad as deep ; in a fully contracted gland the cells are conical or
cylindrical. In the first-mentioned condition their diameter varies
from 0'006-0'018 mm. The larger glands are estimated to possess
about 150 cells, the smaller only thirty to forty (Engelmann).

The cells appear to have no cell-wall, certainly they possess none
on their free surfaces. Their protoplasm distends very freely on
the addition of water. Asa rule some cells are much more gran-
ular than others of the same gland ; each cell has a rounded oval,
clear nucleus, and vacuoles are frequently met with.

The lumen of the gland contains a colourless, transparent, watery
fluid, which contains mucous material.

The duets of the glands are thick-walled cylinders, circular in
section. Their diameter varies from 0°02—-0'05 mm., their length is
equal to the depth of the superimposed epidermis. The wall of the
duct is lined with two or three concentric layers of highly refrac-
tive, nucleated cells. The cells are arranged parallel to the length
of the duct: in transverse section they are sickle-shaped or semi-
lunar. In the upper third or fourth of the duct the inner wall is
lined with a cuticle, very resistent to the action of acids or alkalies :
it is thrown off with the skin in the process of casting. In the horny
layer of the epidermis this cuticle is partially closed by a stoma-
cell (Eberth), (Fig. 230), which possesses a tri-radiate opening.

The glands correspond with the ‘ non-contractile glands’ of Hensche, the ‘ dark
and bright glands’ of Stieda, the ‘ glandule mezzane, piccole e piccolissime (ad epitelio

pavimentoso)’ of Ciaccio, and the ‘small, dark, and medium-sized, bright glands’ of
Eberth.

e. The peculiarities of the skin of the supplemental toe and

THE SKIN AND ITS APPENDAGES. 375

webs. The supplemental toe presents, in the male, a rounded, oval
swelling (Fig. 234 I, D), with the end of the digit projecting from
the distal end.

Normally this swelling is usually of a
grey colour; during the breeding season,
however, the swelling enlarges, and _be-
comes of a black or deep brown colour
(Leydig).

The epidermis covering this swelling
(Fig. 233) is much thickened and produced
into projecting papillae. The cutis also) * tion a a
shows a marked thickening and an increase” epidermis. of the supple-
in vascularity ; the glands are of the kind Ran” siter E. Schultoe
described as mucous glands (Engelmann). —M*snified goo times.
They present, however, an immense increase in size, and at the
same time are so closely applied to one another as to form

Fig. 234.

Fore-foot of a male frog. Vertical section through the swelling on the supplemental toe
D Glandular swelling on the supplemental of a male frog.
toe.
W Warty papillae on the inter-phalangeal euakee
a D Glands. -
Ep Epidermis.
M Muscles.

P Pigment-cells.

the main part of the enlargement (see also Organs of Tactile
Sensation).

In the webs the various layers of the corium are more or less

376 THE SKIN AND THE SENSE-ORGANS.,

fused together, and cannot be distinguished from each other ; the
glands are, as a rule, smaller than on the general surface of the

skin.

f. The blood-vessels and lymphatics of the skin.

(1) The blocd-vessels of the skin are arranged in two networks ;
the one is situated immediately beneath the epidermis, and consists
of fine capillaries, forming a fine-meshed network, which enclose the
ducts of the glands. The meshes vary considerably in size and

Fig. 235.

The blood-vessels and lymphatics of the skin ; after Langer. Arteries striped, lymphatics shaded.

I. Vertical section through skin of thigh.
II. Horizontal view of arteries and lymphatics of the skin.
III. Peculiar tortuous arteries of the lamina inguinalis,
IV. Arteries and lymphatics of the web,

shape (Hyrtl and Langer). The second network of vessels is situ-
ated under the cutis; the vessels forming it are small, and the
meshes formed are large. From this network vertical branches
pass to form the superficial network ; these branches usually course
along the strands of vertical fibres already described, and break up
to form capillaries only when they reach the deeper surface of the
epidermis (Langer), (Fig. 235 1).

In some situations, however, the vertical branches divide earlier ;
this is especially the case in parts where the glands are very closely
packed, as in the nictitating membrane, the upper lip, and the

nn ans a

THE ORGANS OF TACTILE SENSATION. 377

swelling of the supplemental toe (in the male). In these parts the
division takes place at the deeper surface of the glands (Langer).

A peculiar arrangement of the cutaneous blood-vessels is found in
the lamina inguinalis, where a chain of reddish points can be made
out with the naked eye; examined more carefully (Fig. 235 III)
each reddish point is found to be a complex loop of capillaries.
They extend from the skin to the hinder lymph-hearts, where they
form a close network which partially invests the lymph-hearts

_ (Langer).

(2) The lymphatics of the skin (see also p. 252), like the
arteries, reach the deeper surface of the epidermis by coursing along
the bands of vertical fibres; they then form a network of capil-
laries with rounded meshes (Fig. 235 I, I, IV), and lying imme-
diately under the epidermis, and a network which surrounds the
various glands. The lymphatic-capillaries are as a rule larger than
the blood-capillaries. The lymphatic network lies beneath the
blood network, and the vessels of the two systems branch indepen-
dently (Langer).

In those parts where the glands are placed closely together this
arrangement is modified, and corresponds with the modifications
found in the blood-capillaries in these regions. The vertical branches
divide so as te form a network below the glands, and from this ver-
tical branches pass in the same direction between the glands to form a
secondary network on the superficial surface of the glands (Langer).

g. The nerves of the skin. The cutis is very richly supplied
with both medullated and non-medullated nerves. In the subcuta-
neous tissue the nerves destined for the skin branch freely to form
numerous fine twigs, which, without actually inosculating, form a
fine meshwork. From the larger trunks numerous vertical branches
pass vertically to form a secondary network, from which both coarse
and very fine twigs pass to encircle the glands. The fine fibres which
supply the glands are non-medullated and possess oval nuclei ; their
diameter varies from 0°001—-0'002 mm. The number of nerve-fibres
is not much smaller than that of the muscle-fibres (Engelmann).
(See also Organs of Tactile Sensation.) |

Il. THE ORGANS OF TACTILE SENSATION,

The organs of tactile sensation are the nerve-plexus of the epi-
dermis, the touch-spots of Merkel, the lateral sense-organs, and the
touch-corpuscles of the tendons.

378 THE SKIN AND THE SENSE-ORGANS.

a. [The nerve-plexus of the epithelium is very incomplete as
compared with the plexus found in the epithelium of the cornea ;
here and there a few non-medullated fibres have been traced a short
distance between the epithelial cells. No such mode of nerve-
terminations in the epithelium as is described by Eberth and Macul-
lum in the tadpole can be found in the adult. |

b. The touch-spots. What knowledge we possess of these
organs is due to the labours of Leydig, Ciaccio, Eberth, and more
particularly those of Merkel.

At the base of each papilla, which contains such a touch-organ,
is found a number of colourless, flattened cells, arranged either in a
single layer, or heaped up and connected with very fine nerve-fibres.

Fig. 236.
I. TI. -

I. Lateral sense-organ of tadpole of frog. Half-schematic.

€ Central zone (nerve-epithelium),

Mi Membrana limitans.

p Peripheral zone (sustentacular cells).
R Hyaline tube.

Il. Touch-corpuscle from the sheath of a digital tendon of the frog ;
after Lowe. Schieck, Oc. O,, Obj. 9.

The flat surface of the cells is parallel to the surface of the body,
and they do not form a separate or circumscribed body, they are
therefore better spoken of as touch-spots than as true touch-bodies
(Merkel). The larger organs are found in the papillae, but smaller
ones may be found on any part of the skin.

These organs are best seen in the prominence or swelling upon the
supplemental toe during the breeding season; they are numerous
on the dorsal surface of the trunk, but occur most frequently on
the under surface of the hinder feet (Planta pedis). After the

2‘ ae re

-o

mi

THE ORGANS OF TACTILE SENSATION. 379

breeding season the organs of the thumb undergo a retrogressive
change, which results in a network of spindle-shaped and branched
cells with fibres (Wiedersheim).

ec. The lateral sense-organs attain their highest development in
the tadpole ; in the adult the organs have undergone a retrogressive
change, the result of which is that the organs are diminished in
size; the whole organ sinks by the formation of a tube, which is
then closed by a mucous secretion, consequently the organ is
functionless : with this loss in function and change in position of
the organs a corresponding diminution of the ramus lateralis nervi
vagi occurs (Merkel).

Each lateral organ (Fig. 2361) consists of a slightly slvedad papilla,
with the centre depressed, and in each may be distinguished a central
and a peripheral zone (c,y). The central zone consists of a group of
pear-shaped cells, with the narrower ends directed towards the free
surface; each is connected below with a nerve-fibril, while above it
bears a short, stiff cilium. The cilia are enclosed in a delicate
hyaline tube (/), which is open superficially, closed by the papilla
below ; consequently the cilia are in direct contact with the sur-
rounding medium. The peripheral zone is a layer of pale, flattened,
cylindrical cells (py) ; they possess, at their upper borders, a perforated
membrana limitans (M7), through which the cilia pass. These
cells serve as a support to the central cells, and are themselves
surrounded by ordinary epithelial cells.

The distribution and arrangement of the lateral organs is alike in fish and larval
amphibia. They are most numerous on the head, where they surround the eye, and
are continued forwards to the snout and on to the lower jaw. All these organs on
the head are in connection with the trigeminal nerve. A line of these organs passes
from the hinder part of the circumference of the eye along the gill-cover to the neck,
where the lines of opposite sides are usually, though not constantly, joined by a
transverse line of the same organs ; thence the lines are continued along the trunk to
the tip of the tail, In fish there exists, as a rule, only one pair of such longitudinal
lines (Linea lateralis); in anura-larvae, proteus, and in all salamanders there are

three pairs: of these one pair lies near the vertebral column, the second at the
junction of the flank with the abdomen, and the third corresponds to the lateral line
in fish (Malbranc).

At an early developmental period each metamere possesses one pair of such lateral
organs ; in later life, however, this simple arrangement is lost, and each segment
usually possesses a group of organs.

The organs of the trunk and tail are supplied by branches of the Ramus lateralis
nervi vagi. Both in fish and amphibia a reparative process, by means of fission,
occurs ; as a consequence the organs are found in various stages of development.

d. [The touch-corpuscles of Golgi and Liwe (Fig. 236 II) are
found on the jomts of the digits. They are surrounded by con-

380 THE SKIN AND THE SENSE-ORGANS.,

nective-tissue and are spindle-shaped ; the two ends of the spindle
are glassy in appearance, the middle portion is fibrous. In the
thickest part of the corpuscle is a zone of nuclear bodies.

They are regarded as touch-bodies(Golgiand Liwe). Golgi (/. c.)
describes two kinds of touch-organs in connection with muscle and
tendon ; one class correspond with those just described, he names
them ‘nervous muscle-tendon organs.’ The second class he com-
pares with the touch-bodies found in the conjunctiva. |

Ill. THE ORGANS OF TASTE.

The organs of taste are not confined to the surface of the tongue,
but are also found on the mucous membrane of the roof of the
mouth, especially in the neighbourhood of the vomerine teeth ; on
both roof and floor of the mouth these organs can be traced to the
commencement of the oesophagus.

[The mucous membrane ‘of the tongue possesses two kinds of
papillae and numerous glands. .

a. The filiform papillae are the more numerous ; they are conical
or thread-like in form, and consist of connective-tissue, with a few
striated muscle-fibres ; they include blood-capillaries, but no nerves
have been traced into them (Leydig). They are covered with
ciliated epithelium and goblet-cells.

b. The fungiform papillae are much larger, and are paler than
the filiform papillae. The free ends of these papillae are broader
than the bases, and when the epithelium is removed the free ends
_ present a concavity. From the base to the border of the free surface
each papilla is covered with the usual oval, ciliated epithelium,
but at this border an abrupt transition takes place. The
epithelium covering the end of the papillae is of three kinds:
goblet-cells, cylindrical cells, and forked cells; the three forms of
cells are quite characteristic, and no intermediate transitionary forms
are met with.

(1) The goblet-cells (Fig. 237 I) are arranged vertically to the
free surface of the papilla; they are from o°020-0°024 mm. in
length, and from oo1—o'02 mm. in diameter. In the lower third
of the cell is found a nucleus of about 0-008 mm. in diameter, and
this encloses a nucleolus of about o‘oo1 mm. in diameter. Close
underneath the nucleus the cell is contracted to form an irregular
process or foot. The contents of the cells are a very finely granular,

THE ORGANS OF TASTE. 381

transparent protoplasm. These cells form the outermost part of the
epithelium, covering the end of the papilla; all the cells belonging
to the same papilla are of the same size. In consequence of the
- mutual pressure which they exert on each other they present, m
transverse section, six-sided outlines (Fig. 237, 2). The nuclei of
adjacent cells are placed at almost exactly the same level. By the

Fig. 237.

I. Various parts from the fungiform papillae ; goblet- and forked cells ; only cylindrical
after Engelmann. cells remaining. Magnified 400 times.

1, Nerves of a fungiform papilla. Magnified 450 5- Goblet-cell, with swollen contents. Magni-
times. fied 450 times.

2. Surface view of the epithelium, after five 6-13- Various forms of isolated forked cells.
minutes’ action of iolized seram. Magnified Magnified 450 times.
600 times. e IL. Sections of two glands of the tongue ;

3- Goblet-cell with adjacent forked cell. Magni- after Biederman,
fied 450 times. x. Resting-gland.

4. Portion of the papilla, after removal of the 2. Gland after stimulation.

action of reagents on these cells very remarkable forms are obtained,
in consequence of the protoplasm swelling and being forced up-
wards (Fig. 237, 5).

(2) The cylindrical cells (Fig. 237 I) have rounded free extre-
mities, which reach to the general surface of the epithelium; the
remainder of the cell is cylindrical except towards its lower ex-

382 THE SKIN AND THE SENSE-ORGANS.

tremity, where it is slightly dilated and encloses an oval nucleus :
the protoplasm of the cells is very finely granular. These cells rest
on the connective-tissue of the papilla, and are in close juxtaposition,
so that several hundreds of them are found on one papilla.

The spaces between the upper parts of the cylindrical cells are
occupied by the goblet-cells and by the forked cells.

(3) The third form of cell found on the fungiform papillae are

named forked cells (Fig. 237 1) by Engelmann. The body of the’

cells has an ellipsoidal form, is from 0:006—o'co8 mm. in its longer
diameter, and 0°003-0'004 mm. in the shorter diameter. Processes
arise from both poles. The peripheral processes arise by a short
common stem, which then divides into two or rarely three branches ;
the whole process is from 0°004—0'008 mm. in length, and is always
just sufficiently long to reach the general surface of the epithelium :
when the peripheral process is long the central is usually shorter,
and vice versd.

The central processes arise by a stem from o’o001-0'002 mm. in
thickness, which usually divides dichotomously. The length of this
process may be as much as 0'025 mm. or almost nil.

The forked cells are about twice as numerous as the goblet-cells,
_they occupy the spaces between the eylindrical cells and the goblet-
cells. The branched central processes form a network on the
connective-tissue of the papilla, which is, at this point, perforated
by a rich plexus of fine non-medullated nerve-fibrils. It is not de-
cided whether the processes of various cells inosculate. Engelmann
regards these forked cells as the taste-cells and as the sensory
nerve-ending's.

The bodies of the fungiform papillae contain blood-vessels and
nerves, the latter enter as medullated nerves, but lose the medulla
somewhat abruptly towards the upper end of the papilla, where they
form a sort of nerve-cushion (Nervenkissen, Engelmann). |

Taste-organs are also found on the roof and other parts of the
mouth, and present many points of resemblance to the lateral sense-
organs. Like them they present a peripheral zone and a central
zone; the cells of the latter, however, are not longer than the
peripheral cells, and possess no cilia (J. van der Hoeven, Merkel).

THE NOSE. 383

IV. THE NOSE.

The anterior nares or nostrils are two small openings, placed di-
rectly in front of the anterior angle of the eye ; the distance between
the eye and the corresponding nostril being, in the case of adult
animals, about five or six millimeters. The anterior nares are sur-
rounded by rims, which are contracted below, and so form very short,
tentacular-like prominences.

The posterior nares (choanae) are about four millimeters from
the anterior nares, consequently the long axis of the nose is, approxi-
mately, of this length. (For the external muscles of the nose,
see p. 59-)

The boundaries of the nasal cavities are as follows :—the roof of
each cavity is formed by the dorsal plate of the sphenethmoid, the
nasal bone, and the premaxillary bone; the floor is formed by the
vomer and the palatine bone, the inner wall by the vertical septum
of the sphenethmoid, the outer wall by the premaxillary and max-
illary bones, the anterior wall by the premaxillary bone, and the
posterior wall by the sphenethmoid. The cartilaginous portion of

_ the nasal skeleton (see also p. 27) projects into the general cavity

and subdivides it into various sinuses, which have been the subject.
of careful investigation by Born and Wiedersheim.

a. The nasal cavities are best examined by means of serial trans-
verse sections ; in a section through the anterior nares (Figs. 238,
239) there will be seen three sinuses on either side :—

(1) The superior sinus (on) is large, rounded, and plaéed against
the cartilaginous septum ; the sinus is lined with olfactory epithe-
lium. Posteriorly the sinus extends beyond the posterior nares, and
is bounded by the anterior surface of the sphenethmoid. In front it
ends in a rounded concavity, likewise lined with olfactory mucous
membrane. Opposite the anterior nares the cavity is partially sub-
divided, by a longitudinal process on the floor, into two cavities ;
the anterior nares open into the external chambers, and therefore
not directly into the main cavity of the superior sinus. The supe-
rior sinus communicates with the inferior sinus by a narrow, almost
vertical, slit.

(2) The inferior sinus (wz) is narrow and flattened from above
downwards ; it is placed against the maxillary bone, and represents
the maxillary sinus of the frog. Externally it possesses a de-
scending arm.

The inferior sinus is continued backwards and opens on its

384 THE SKIN AND THE SENSE-ORGANS.

inner side into the posterior nares, or rather into the mouth. The
descending arm extends only a short distance forwards, to terminate
near the point where the superior and inferior sinuses communicate
by only a narrow opening. ‘This sinus is on the whole broader in
front than behind, and has a general direction from without, in-
wards and forwards underneath the superior sinus.

Fig. 238.
Ep

Frontal sections through the nose of two
tadpoles ; after G. Born,

. A Anterior naris,
Fig. 239. b Cartilaginous floor.

C Cutis.

d Cartilaginous roof.

Ep Epidermis.

gi Intermaxillary gland.

gni_—_— Lower nasal gland,

gus Upper nasal gland,

K Maxillary sinus.

i Concha narium (os lachrymale).

m Maxillary bone.

MS — Oral mucous membrane.

ok” —s— Cartilage.

on Upper blind: sac.

R Pharyngeal gland.

S Nasal septuin.

se Septum between the upper and lower
nasal cavity.

sn External blind sac,

T Trabeculae,

Th Lachrymal duct.

un Lower blind sac.

(3) The lateral sinus (sz) is situated in the partition between the
superior and inferior sinuses, or rather between the external chamber
of the upper sinus and the inferior sinus. The lateral sinus is tri-
angular in form, being narrow in front and broad behind ; at its

* 6 et ISR ey. el es areata gy

:
,

>
&

THE NOSE. 385

inner posterior angle it opens on the free border of the horizontal
partition between the superior and inferior sinuses ; this opening is,
however, continued along its roof, so that-the lateral sinus opens
also into the superior sinus.

b. The nasal cartilages. The two nasal cavities are completely
separated by the cartilaginous septum (Figs. 238 and 239 S), and
are for the most part lined by cartilage. The anterior end is
formed of concave cartilages, while the posterior, being situated in
the sphenethmoid, is usually more or less ossified in the adult. The
posterior wall has two openings: a larger near the septum for the
olfactory nerve, and a smaller, more externally, for the nasal branch
of the trigeminal nerve.

The anterior wall is more complex than the posterior, being
thicker in the middle than at the sides, and possessing three blind
sacs for the three sinuses. From the anterior wall two processes
project backwards between the sacs and enclose them more or less
completely.

Of the three sacs or cavities only th the lower is completely sur-
rounded by cartilage. The upper sac is in part bounded by a shell-
shaped, concave cartilage (Concha narium, of various authors; Os
lachrymale, Born), which covers it anteriorly and externally, and is
attached by a small base to the roof of the lower sac (Fig. 239, 7),
its upper border bounding the anterior naris (Fig. 15). The upper
and external parts of the upper sac have no cartilage. The carti-
lages of the outer wall of the lower, blind sac extend backwards to
the pomt where the maxillary sinus commences to descend: the
roof, however, is prolonged further backwards by two small cartila-
gimous processes ; the inner is short, the outer forms the roof of the
descending arm of the sinus, and joins a cartilaginous process, which
commences at the anterior portion of the roof of the nasal cavity,
passes backwards and downwards to a broad plate, and forms an in-
complete outer wall to the nasal cavity. There are also three carti-
laginous processes—a. One arising from the outer side of the floor
at the level of its junction with the anterior wall; it is a flattened
process and passes outwards, and bifurcates at its end to meet the
premaxillary and maxillary bones (this is the Oberkieferfortsatz of
Ecker), (p. 28, Fig. 14 ”)). . A delicate process on either side,
described by Wiedersheim (see p. 280). y. The third pair of pro-
cesses are fully described for the first time by Born ; each arises at
the lower border of the corresponding Concha narium, passes forwards
and downwards under the ascending process of the premaxillary to

ce

386 THE SKIN AND THE SENSE-ORGANS.

the point where process 8 is attached to this bone. The processes
are flat and approach one another obliquely ; in older animals they
are united at the point of contact.

At the junction of the anterior wall, the septum, and the floor is
a large aperture in the cartilaginous capsule, through which passes
the chief nasal branch of the trigeminus, which supplies numerous
branches to the intermaxillary gland.

e. The glands of the nasal region are Bowman’s glands, the in-
termaxillary glands (Wiedersheim), the lower nasal gland (Born),
the upper nasal gland (Born), the pharyngeal gens (Born), and the
lachrymal duct.

(1) The intermaxillary gland
(see p. 280).

(2) The lower nasal gland is —
placed along the septum and ex-
tends as far back as the posterior
nares, opening by its ducts (Figs.
238 and 239 gui) into the inferior
blind sac of the nasal cavity. In
histological structure it corresponds
with the intermaxillary glands,
except that the glandular tubes
are somewhat smaller, and the
glandular epithelium stains some-
what less easily with carmine
(Born).

(3) The upper nasal gland occu-
pies the space between the Concha
narium (Os lachrymale, Born) and the
1. A. Bowman’s glands in situ from Rana nelghbounng pertilapes, a a i

temporaria ; after C.K. Hoffmann, rounds the anterior naris and the
8, saga teen opening of the lachrymal canal
B. Section of Bowman’s gland ; after °

©. K, Hoffmann, Magnified 300 (Figs. 238 and 239 gus). The
a: abet wd mucous membrane of ere ducts eg og the ah
Rana esculenta ; after Langer. Blood- membrane covering’ the oblique car-
a eee tilage (above described, as passing
from in front, downwards and backwards, and forming an incom-

plete outer wall of the cavity), and its hinder prolongation.

(4) The pharyngeal gland is placed transversely behind the pos-
terior nares, and surrounds the vomerine teeth. A portion of the

THE NOSE. 387

ducts open into the posterior nares, the remainder on the mucous
membrane of the pharyngo-oral cavity at two symmetrically placed
points (Fig. 238 2).

(5) The lachrymal duct (see p. 428) opens into the nasal cavity

at the point where the lateral sinus opens into the external chamber
of the superior nasal sinus.
- (6) [The glands of Bowman (Fig. 240 I) are freely distri-
buted in the nasal mucous membrane. Each gland is usually
rounded or flask-shaped, and consists of a single layer of large epi-
thelial cells possessing distinct nuclei and nucleoli. The epithelium
of the glands possesses no basement membrane (M. Schultze and
Hoffmann’), but is bounded externally by a layer of nerve-fibres
and connective-tissue.

The glands situated more superficially have straight ducts open-
ing on the surface; those placed more deeply have usually curved
ducts (Paschutin). }

d. The mucous membrane of the nasal cavities. That part of
the superior sinus immediately around the anterior naris is lined
with stratified epithelium ; the rest of the nasal cavity is lmed with
columnar ciliated epithelium. The epithelial layer rests on a sub-
epithelial network, and this again on a submucous connective-
tissue layer possessing numerous vessels and nerves.

(1) The epithelial layer (Fig. 241) consists of columnar cells,
which in the olfactory region are of two kinds; in other regions the
epithelium consists of closely-applied ciliated, thick cells, possessing
large oval nuclei, and having irregular, branched bases or ‘ feet.’
The cells are 0°032-0'048 mm. long; the nuclei o'016—-o0'018 mm.
long, and 0°006—0'008 mm. broad. The free borders of the cells
bear a number of fine cilia.

In the olfactory region a second set of cells, olfactory cells, are met
with ; these cells (Fig. 241 IL) possess each an oval body, enclosing
a large nucleus, and a peripheral and central process. The peripheral
processes reach to the general surface of the surrounding epithelium
and there terminate in a number (5-8) of stiff cilia; these cilia are
sometimes o'09 mm. long, they are thicker at their bases than the
ordinary cilia (Schultze) ; according to Hoffmann, a second system of
stiffer and longer cilia is met with; of which each olfactory cell
possesses as arule only one. The bodies of the olfactory cells are -
0009-0010 mm. long, and o'007—-0-008 mm. broad ; the peripheral

? Paschutin describes a basement membrane.
Ce2

388 THE SKIN AND THE SENSE-ORGANS.

processes vary considerably in length, according to the position of
the body (0:03-0:05 mm.). The central processes vary from 0:02—
003 mm. in length. The peripheral processes are considerably
thicker than the central processes. No membrana limitans olfactoria
has been discovered in the frog.

(2) The second layer consists of a network of processes belong
to the bases of the central processes of the superimposed epithelial
and olfactory cells. Numerous highly refractive nuclei possessing
nucleoli are situated in the meshes of this network ; they correspond
in all particulars with the huclei of the
olfactory cells (M. Schultze). According
to Exner the branched processes of the
epithelial cells and of the olfactory cells
unite to form a complex plexus. Other
observers, Paschutin, Cissoff, v. Brunn,
Schultze, and Hoffmann oppose this
view, and hold that the central processes
of the olfactory cells do not unite with
the processes of the epithelial cells, but
that they are in direct continuity with
the fibrils of the olfactory nerve. This
view is probably correct.

The submucous layer has a loose con-
nective-tissue matrix, which encloses the
glands, nerves, and vessels; according
to Paschutin two pigment-layers may
be distinguished: the one, immediately
under the middle layer of this mucous

membrane, is continuous and deeply pig-
=e aliueitseeact Balas mented ; the second is deeper and does
seis a abe pent not form a continuous layer. This layer

I. Surface view of the olfactory - . -
mucous membrane, Magni. 18 extremely rich in blood-vessels and

te ee rege Lo lymphatics (Langer and Paschutin),
" "Magnified 600 times. (Fig. 240 II). The lymphatics are rela-

times.

ILL. Epithelial cells. Magnified 600 tively very large and are very numerous

(Langer).

In this layer the central processes of the olfactory cells form
bundles of fibres, lymg parallel with the surface of the mucous mem-
brane (Paschutin, Cissoff, and Schultze). ]

=f
;
4
3

THE EAR. 389

V. THE EAR.

(Re-written by the translator from Das Gehérorgan der Wirbelthiere,
‘by G. Retzius, 1881.)

The organ of hearing is divisible into two parts, the tympanum
or middle ear, and the labyrinth or internal ear ; an external ear is
absent, unless a very slight depression of the tympanic membrane
be regarded as such.

A. The tympanum (Cavum tympani) is a cavity, bounded ex-
ternally by the tympanic membrane and internally by the capsule
of the internal ear; it communicates by means of the Eustachian
tube (tuba Eustachii) with the pharyngo-oral cavity (Fig. 178).

a. The tympanic membrane lies immediately underneath the
skin, but can be separated- from that structure; externally it
possesses a very slight depression, the»only
trace of an external ear found in the frog.

The tympanic membrane is of a rounded
oval form, being a little wider in the trans-
verse than in the longitudinal diameter; the
membrane is directed outwards.

After detachmg the skin (Fig. 242 I) the
membrane is seen to be attached by its circum-
ference to a ring of cartilage (Annulus mem-
branae tympani; see also p. 26) (at); the rmg
is attached anteriorly and above to the squa- 1, The tympanicmembrane
mosal bone (sq), and in the rest of its cireum- copes Pape pt
ference to the surrounding soft parts, 7. ¢. the Retzius.

M. depressor mazillae (dm), the M. temporalig » Mer rete the
(¢), and their fasciae. In the middle of the ee ae
membrane is a small, rounded, white part (col) —~—_—~Retzius.

which can be traced backwards and upwards “ “Viu"s,, ™mbrme
towards the cireumference. cot Columella.

The membrane consists of fibres of con- im pe vaccecerites A
nective-tissue which radiate peripherally from ) Qyupenc membrane
the central point of attachment of the colu- ‘ ™-temporalis
mella; in the peripheral portion unstriated muscular fibres are
also found (Leydig).

Internally the tympanic membrane is covered by columnar epi-

390 THE SKIN AND THE SENSE-ORGANS.

thelium, a continuation of the mucous membrane lining the tympanic
cavity.

b. The tympanic cavity (Fig. 242 II) is seen, after removing the
tympanic membrane, as a flattened, funnel-shaped cavity. The
walls of the cavity are lined with a pigmented mucous membrane,
under which the cartilaginous ring (aznulus membranae tympani)
extends internally to form the greater part of the wall of the cavity.
The cavity is an elongated oval slit (Fig. 242 I, c#), with its longer
axis directed from above and in front, downwards and backwards,
and leading inwards ; it is bounded above, below, and in front by the
squamosal, behind by the soft parts ; above in the roof is the eartila-
ginous part of the co/wmella. The imner or deeper portion of the
tympanic cavity is bounded in front by the squamosal, and by the
squamous process of the prootici (proc. sguamosus prootici) in front
and above ; internally by the cartilage (primordial-cranium) between
the prootic and the exoccipital ; behind by the J/. depressor mawillae.
This part of the cavity is rounded and covered with mucous mem-
brane, and has in its roof the bony part of the columella, which
covers the foramen ovale ( fenestra ovalis) by its oval, widened end-
piece. This deeper portion of the cavity communicates by a short,
wide Eustachian tube with the pharyngo-oral cavity; the tube is
wide and is of a rounded oval form in section : anteriorly, externally,
and internally it is bounded by the pterygoids, posteriorly by soft
parts, in which is embedded the styloid process.

The tympanic cavity can be examined from without after re-
moving the tympanic membrane, or from below by means of the
Eustachian tube. |

e. The columella auris (Figs. 12, 243) is described by Retzius
as. consisting of three portions, of which the middle is bony, the
external and internal cartilaginous. Parker divides it into four
parts (see pp. 25, 26).

The extrastapedial (Fig. 243 a’,a’’) is attached to the middle of
the tympanic membrane by the oval surface opposite a’, and is
attached by the process a’” to the annulus tympanicus ; this process
of Retzius is the suprastapedial of Parker.

The mediostapedial (Parker), or middle bony piece of Retzius
(Figs. 12 a’, 243 4, 0’), is narrow externally but widens internally
to articulate with the interstapedial. Just before reaching the
latter it gives off a process (4’), to which are attached a few fibres of
striated muscle (77).

tall’ lee

¥
*
e

«
*<
*

* MELBYb. es

1) Saag) ate

_ fossa fenestrae ovalis, and

eee

on -—

THE EAR. 391

The interstapedial (Figs. 12 a, 243 ¢) is cartilaginous; it is
thick with a sharply cut-off, slightly concave end, which is placed
against the fenestra ovalis. The inner surface of the interstapedial
is, however, distinctly
larger -than the opening Fig. 243.
of the fenestra ovalis, con-
sequently it does not fit
in accurately, but is at-
tached to the border of
the opening by means of
connective - tissue ; the
margins of the fenestra
ovalis are hollowed (Fig.
245 II) so as to form a

it is really to the margin The columella; after Retzius. Magnified eight times.
of this fossa that the A. Seen from above.

: . B. Seen from behind.
connective-tissue capsule } wey :
: a Extrastapedial (Parker). Outer cartilaginous portion

of the interstapedial is attached to middle of tympanic membrane (Retzius).
ttach ed a” Attachment of extrastapedial to mediostapedial.
a . a” Suprastapedial(Parker). Portion embedded in mucous
membrane (Retzius).
. - 6 Mediostapedial (Parker). Bo Retzius).
B. The labyrinth or in- 5 Promofmedictapeia.
ternal ear is contained na « — (Parker). Inner cartilaginous piece
A 118}.
capsule formed of bone » _ tnsertion of small muscle.
and cartilage.

a. The capsule of the labyrinth (Fig. 244) is formed of two
bones, the prootic and the exoccipital (according to Hasse this
includes the opisthotic), which are united by cartilage belonging to
the primordial-cranium. The fronto-parietal, squamosal, and para-
sphenoid take only an indirect part m its formation.

On the whole the anterior half of the capsule is formed by the

* prootic, and the hinder half by the exoccipital; the cavity has its

long axis directed from within and above, downwards and outward ;
the cavity is comparatively large and rounded, and contains the
membranous ear.

Four surfaces can be distinguished : a supero-external, an interno-
inferior, an anterior, and a posterior (Retzius).

(1) The supero-external surface is divided into two parts by a
strong, transverse, bony ridge, the processus squamosus prootict.
The upper half is concave, is directed upwards and outwards, and
is formed by the prootic ; it is separated from the anterior surface

392 THE SKIN AND THE SENSE-ORGANS.

by a bony ridge, which marks the position of the anterior semi-
circular canal. Posteriorly and medianly it is separated from the
posterior surface by a cartilaginous ridge, running from above,
downwards and outwards, which marks the position of the posterior
semicircular canal. ‘The cartilaginous
hinder root of the processus squamosus
prootici arises in the cartilaginous ridge
just mentioned, and runs outwards and
forwards, covering the external semi-
circular canal.
The lower half of the supero-external
surface (under the processus squamosus)
is irregularly concave; immediately
get we eh gtr he under the proc. squamosus is a shallow
Rana esculenta ; after Retzius. En- groove in the prootic; it is continued

Fig. 244.

larged five times.

ps.

Aquaeductus cochleae.

. Aquaeductus vestibuli.

Posterior semicircular canal.

. Canalis rami anterioris acustici.
. Canalis rami posterioris acustici.

Fenestra rotunda.

*. Fovea sacculi et cochleae.

Trigeminal foramen.

. Cartilaginous suture.

Exoccipital.

*. Prootic.

Parasphenoid.

on the exoccipital to the jugular fora-
men. The remaining part of this sur-
face consists of a rounded cartilage, and
is part of the primordial-cranium car-
tilage between the prootic and the
exoccipital ; posteriorly it has a small
oval aperture, the foramen ovale ( fenestra

vestibulare), which with the groove is
covered by the columella. Above the aperture the cartilage narrows
and is continued to the processus squamosus.

(2) The posterior surface is directly continuous with the supero-
external surface, and is formed by the exoccipital. This surface lies
behind the ridge formed by the posterior semicircular canal, it is
concave, and has two small apertures, separated by a narrow, bony
process, and situated near the jugular foramen; these are the
JSoramen rotundum { fr.) and the aquaeductus cochleae (ac.).

(3) The anterior surface is altogether bony and formed by the
prootic(pr.); the anterior surface of this part of the wall is continuous
with the surface of the cranium, and abuts on to the large tri-
geminal foramen (f¢.); below it.is continuous with the under
surface of the cranium, below and externally it articulates with the
pterygoid.

(4) The interno-inferior surface is as a whole hollowed in-
ternally, the upper part being pushed in towards the cranial cavity.
It is formed by the prootic anteriorly, by the exoccipital posteriorly,
and is completed by the cartilage lying between these bones. In

—

THE EAR. ; 393

the middle of the upper part of the cartilage is a small oval opening
(av.), the ap. aquaeductus vestiluli: about midway between this
aperture and the jugular foramen is a second opening in the
cartilage (cra.), the opening of the canalis rami anterioris (vestibu-
Jaris) acustici : a little behind and above this is the opening of the
canalis rami posterioris (cochlearis) acustici, situated in the exocei-
pital. The cartilage between the prootic and exoccipital in the
lower half of the mterno-inferior surface rests on the parasphenoid.

b. The position of the soft parts in the capsule. The large
outer, rounded part of the cavity contams the saccule and cochlea
( fovea sacculi et cochleae) ( fsc.). Above, the cavity is more irregular,
and contains the utricle and the simus utriculi superior. In
front and externally, imbedded in a deep groove, are the anterior
and external ampullae (fovea ampullae anterioris et amp. externae) ;
to these are attached the corresponding semicircular canals. The
anterior semicircular canal opens above and externally into the canal
of the sinus utriculi superior ; the posterior passes into a groove for
the posterior ampulla ( fovea ampullae posterioris), and opens above
and internally into the posterior semicircular canal. The external
semicircular canal courses in the processus squamosus prootici, the
posterior in the cartilage (Fig. 244 cp) between the prootic and
exoccipital, and the anterior in the prootic. The upper and poste-
rior part of the anterior semicircular canal is imbedded in cartilage,
on which rests the parasphenoid.

ce. The perilymphatie space (Fig. 245 I and II. The mem-
branous labyrinth does not occupy the whole space enclosed by the
hard parts but is surrounded by the perilymphatic space, which
contains the perilymph. The periosteum and perichondrium form
the outer lining of the space, and are for the most part pigmented.

The perilymphatic space is widest in the lower part of the organ,
in the region of the fovea sacculi et cochleae, especially externally
and behind (yer); in front it is much narrower (yer'). A little
higher, im the region of the teymentum vasculosum, the space is
wanting, as the membranous. labyrinth is here attached to the
periosteum.

Around the utricle and saccule the space is comparatively wide ;
it is continued into the bony canals and ampullae. In the semi-
circular canals the space is wider on the concave side than on the
convex side, the membranous canals being placed eccentrically, as
are also the ampullae, though to a less extent. The periosteum and

394 THE SKIN AND THE SENSE-ORGANS.

perichondrium lining this cavity form a very delicate, pigmented
membrane, formed of numerous fine elastic fibres which cross each
other irregularly; its inner surface is lined with an incomplete
layer of branched protoplasmic cells with large oval nuclei. From

Fig. 245.

The membranous labyrinth of Rana esculenta, within its natural covering of periosteum ;
after Retzius. ;

I. Seen from the side ; magnified ten times.
II. The hinder half ; magnified ten times. Seen obliquely from above, and in front, and from

the side.
aa Anterior ampulla. pb Pars basilaris cochleae,
adf Apertura fenestrae ovalis. per Wider part of perilymphatic space.
al, Apertura lagenae. per’ Narrower part of perilymphatic space,
ap. Posterior ampulla, ra. Ramus anterior.
apb. Opening into the pars basilaris. ym: Ramulus neglectus.
ca Anterior semicircular canal. rp. Ramus posterior.
ce External semicircular canal. rs. Ramulus sacculi,
cp Posterior semicircular canal. Ss. Saccule.
djo Ductus fenestrae ovalis, sfo Saccus fenestrae ovalis.
dp Ductus perilymphaticus. - spl Saccus perilymphaticus.
dp’ _Saccus perilymphaticus. ty Tegmentum vasculosum.
l. Lagena cochlea, u Utricle.

ms, Macula sacculia.
this membrane numerous irregular bundles of fibres, in the form of
trabeculae, pass into the space and form a rich network, which is
attached internally to the outer surface of the membranous labyrinth
and holds it in position. Free nucleated leucocytes are occasionally
met with in the meshes of this network. The perilymphatic space
is prolonged into two subsidiary cavities :—

(1) The ductus fenestra ovalis (Retzius), (Fig. 245 dfo) com-
mences as an opening (ad/’) immediately opposite the foramen ovale
of the hard capsule, which leads into a moderately large canal, the
structure under consideration. It passes forwards and outwards
through the fenestra ovalis between the interstapedial and the outer
wall of the capsule into the oval depression (fossa fenestrae ovalis),

THE EAR. 395

and rapidly widens to form a short, flattened, blind sac (saccus
fenestrae ovalis), which is lodged in the’ fossa (sfo). Its walls are
thin and pigmented.

(2) The ductus perilym-
phaticus (Hasse), (Fig. 245
dp) passes above and behind
the ductus fenestrae ovalis, be-
hind the auditory nerve, and
near the cochlea, then behind
and above the /agena to the
aquaeductus cochleae (Fig. 244
ac), where it forms a short,
wide tube, which passes back-

wards : ards Part of the outer wall of the perilymphatic space ;
and inw through "iter Rotsius, Verick’s Syst., Obj. III, Oc. 3.

this canal to the canalis jugu- sar Nadiad .
laris ; here it lies close to the e- ic i sa network.

nerves and forms a short oval

sac (saccus perilymphaticus) (dp'), which communicates with the sub-
arachnoid space of the cranial cavity by means of a tube from the
neck of the sac. The walls of this structure are thin and formed of
connective-tissue with very few pigment-cells. The other extremity
of the tube passes to the pars dasi/aris and under the sinus post. utri.,
’ between it and the pars neglecta ; it then courses to the outer side
of the hinder end of the external semicircular canal: the tube
then bends downwards to the outer side of the utricle and saccule to
open into the general perilymphatie space.

d. The membranous labyrinth (Figs. 247, 248) has the fol-
lowing parts: the utricle and sinxus superior, the recessus utriculi,
the anterior semicircular canal and anterior ampulla, the external
semicircular canal and external ampulla, the posterior semicircular
canal and the posterior ampulla, the saccule, ductus endolymphaticus,
and saccus endolymphaticus, the pars neglecta, the lagena cochleae, the
pars basilaris cochleae, and the so-called tegmentum vasculosum.

In addition the following nerve-terminations can be distinguished :
(1) The macula ac. recessus utriculi, (2) the three cristae acusticae am-
pullorum, (3) the macula ae. sacculi, (4) the macula ac. neglecta, (5) the
papilla ac. lagenae cockleae, and (6) the papilla ac. basilaris cochleae.

The auditory nerve divides immediately beyond its origin from
the medulla oblongata to form a ramus anterior and a ramus posterior,
which course alongside each other for a short distance, the latter
lying behind and above the former. The R. anterior runs forwards

396 THE SKIN AND THE SENSE-ORGANS.

and outwards under the utricle, giving off the 2. saccu/i, which runs
downwards and outwards; the R. rec. utriculi is then given off as
a number of fibres, which run upwards and forwards; the main
nerve then divides to form the R. ampullae anterioris and the R. am-
pullae externae, which course together for a short distance and then
separate to reach their respective ampullae. The 2. posterior runs
backwards and outwards, gives off the R. /agenae, and then divides
to form the 2. neglectus, ranning upwards, the R. dasi/aris running
downwards and backwards, and the R. ampullae posterioris which
courses backwards and outwards.

(1) The utricle (wtriculus) (Figs. 247 and 248 w) is irregularly
cylindrical in form: commencing at the recessus utriculi it passes
forwards and outwards ; then backwards, inwards, and upwards, to
terminate at the siaus posterior, where it is slightly contracted. At
about its middle it is divided into an anterior and a posterior part by
an incomplete, sickle-shaped partition, formed by the posterior
semicircular canal opening obliquely into the utricle, and so
causing a fold in the posterior wall: on the anterior wall there is
no fold ; the aperture left in the partition is the apertura utriculi.

The posterior part of the utricle receives the sinus superior, which
is formed by the junction of the two vertical semicircular canals.
The anterior part of the utricle receives the hinder dilated end of

the external semicircular canal by an opening in its posterior wall, -

close to the apertura utriculi. In the lower wall or floor is the
narrow opening leading into the saccule (canalis utriculo-saccularis) :
this opening is placed with its long axis parallel to the long
axis of the utricle, with its broader end posterior, and the narrower
end anterior.

(2) The recessus utriculi (Figs. 247 and 248 rec). The anterior
end of the utricle widens and curves downwards and outwards to
form the recessus utriculi ; on its floor is a thin, kidney-shaped plate
or otoliths, resting on the macula ac. recessus utriculi (mu), which re-
ceives the ramulus rec. utriculi ; under it the ramulus amp. anterioris
and the ramulus amp. externae run forwards and close together to
reach their respective ampullae, which are close together at the
antero-external wall of the recessus utriculi. The otolith is a glassy,
homogeneous plate, with numerous vacuole-liké spaces and striated
borders ; it covers the whole of the macu/a.

(3) The anterior ampulla and semicircular canal (Figs. 247,
248, aa, ca). The anterior ampulla is a rounded, oval vesicle,
with a depressed roof (Fig. 250 I); on the floor is a transverse

0 Sec nine a ne ra ei Na a i =

al

THE EAR. 397

low septum, which bears the crista acustica (er) on its free border ;
seen from above the crista acustica (Fig. 249 II, aa, er) has concave
Fig. 247.

ca

aa

The right membranous labyrinth of Rana esculenta ; after Retzins. Magnified 20 times. Fig. 247
seen from the inner side ; Fig. 248 seen from the outer side.

aa Anterior ampulla. mn Macula acustica neglecta. rb Ramutus basilaris,

ae External ampulla ms Macula acustica sacculi rec Recessus utriculi.
ap Posterior ampulla. mu Macula acustica recessus ri Ramulus lagenae.
apn Apertura partis neglectae. utriculi. rn Ramoulus neglectus.
au Apertura utriculi. po Pars basilaris cochleae rs Ramiulus sacculi.

s Saccule.
sp Sinus utriculi posterior.
cp Posterior semicircular canal raa Ramulus ac. anterioris. ss Sinus utriculi superior.
i ty Tegmentum vasculosum.
uw Utriculus.

E
3
5
5

borders anteriorly and posteriorly ; the ends are broad, rounded, and

$e

398 THE SKIN AND THE SENSE-ORGANS.

somewhat raised ; and in the middle it presents a small elevation
(Fig. 249 cr). On the crista acustica rests the cupula terminalis
(Fig. 250 I, ew); this is arched above but of the same form as the
crista acustica below, from, which it is separated by an even slit-like
space; the ends are not rounded but hollowed out. The substance
of the cupula is very soft and has parallel striations, formed of fine
fibres and running from above downwards ; it separates very easily
from the crista acustica. The anterior ampulla is directed forwards,
outwards, and slightly upwards, to open into the anterior semicir-
cular canal (cazialis m. anterior) (ca), which curves first upwards and
forwards, then backwards, inwards, and upwards, to open by means
of a slightly dilated end into the sinus superior utriculi,

(4) The external ampulla and semicircular canal (Figs. 247,
248 ae, ce). The external ampulla lies immediately external to the
anterior ampulla ; it also is an oval vesicle, and corresponds with the
anterior ampulla in size and shape, except that the roof is higher.
The roof is directed backwards, the floor forwards; the septum
transversum is low, placed vertically, and bears a triangular, slightly
_ depressed crésta acustica: the broader, rounded end of the crista is
directed upwards, the apex downwards. The corresponding ‘cupula
terminalis is relatively high, and is of the same shape as the crista,
and is striated. The external ampulla is continuous with the ex-
ternal semicircular canal (canalis m. externus) (ce), which courses
outwards and backwards; then backwards, inwards, and slightly
upwards, touches the roof of the posterior ampulla; then curves
forwards and inwards to terminate by a slightly dilated end in the
anterior part of the utriculus.

(5) The posterior ampulla and semicircular canal (Figs. 247,
248, and 249 ap, cp). The posterior ampulla commences at the
posterior end of the szaus post. uiriculi, and is directed outwards
and backwards. It corresponds in all other points with the anterior
ampulla. The posterior semicircular canal (ce) (canalis m. post.),
into which the ampulla opens, curves upwards, inwards, and for-
wards, to open into the upper end of the sizus superior.

(6) The saceule (s), ductus endolymphaticus (de), and the
saccus endolymphaticus (Iigs. 247, 248, 249). The saccule (s)
is an oval vesicle, placed under the anterior part of the utricle and
directed outwards and downwards ; below it is flattened in a di-
rection from in front and within, outwards and backwards; above
it is wider. In the inner and anterior surface is the rounded, oval
macula acustica sacculi (Figs. 247 and 248 ms), to which is distri-

THE EAR. : 399

buted the 2. sacculi (rz) from above; a large otolith rests on the
macula and occupies a large portion of the cavity, more especially
the lower portion. The tubular ductus endolymphaticus (de) arises
by a narrow oval opening placed in the upper and inner part of the

Fig. 249.

> waste:

The membranous labyrinth of Rana esculenta ; after Retzius.

IL Part of membranous labyrinth to show relations of the ductus and saceus endolymphaticus
to the cochlear part ; ni

Ii. The recessus utriculi and the external ampulla ; magnified.

Ii. Toshow tegmentum vasculosum, pars basilaris, pars neglecta, etc.

IV. Toshow relations of the cochlear part to the pars neglecta.

aa. Armpulla anterior. 2 Lagena cochleae. rap. Ramulus amp. posterioris.

ae. Ampulla externa. ma. Macula ac. recessus utri- rb. Ramulus basilaris.

al. Apertura lagenae. euli. rec. Recussus utriculi-.

ap. Posterior ampulal. mn. Macula ac. neglecta. ri. Ramulus lagenae.

apn Apertura partis neglectae. mp. Membrana basilaris. rn, Rarmulus negiectus.

au. Apertura utriculi. p>. Pars basilaris cochleae. rp. Ramus posterior.

ea. Canalis m. anterior. pe’. Darkspot on eitherside of rs. Ramulus sacculi.

ee, External semicircular canal. crest of ampulla. & Saccule.

ep. Posterior semicircular canal. pl. Pars ac. lagenae. sp. Posterior semicircular

er. Crista i ppb. Papilla ac. basilaris. spl. Saceus perilymphaticus.

cus, Canalis utriculo-saceularis. ra. Ramus anterior. ss. Sinus utriculi superior.

de. Ductus endolymphaticus. raa. Ramulus amp. anterioris. fv. Tegmentum vasculosum.

dp. Ductus perilymphaticus. rae. Ramulus amp. externa, w. Utricle.

wall, rans upwards and to the angle between the utricle and the
sinus superior, continues in the same direction for a short space, and
then curves inwards to pierce the apertura aquaeductus vestibuli, and
so reach the cranial cavity. It then forms a large, thin-walled sac

400 THE SKIN AND THE SENSE-ORGANS.

(saccus endolymphaticus), placed between the brain and cranium.
The sac is very vascular and contains crystalline otoliths.

(7) The pars neglecta (Figs. 247, 248, 249) was described by
Hasse as the ‘first part of the cochlea’ (‘ Anfangstheil der Schnecke’),
but according to Retzius it does not belong to the cochlea. It is
placed above and in front of the pars basilaris cochleae, above and a
little behind the /agena cochleae, therefore above the upper and pos-
terior part of the saccule, and under the middle part of the utricle.
It is really a prolongation of the saccule, with which it communi-
cates by an elongated oval opening placed externally and immedi-
ately below the opening of the canalis utriculo-saceularis. It is an
oval vesicle, with its roof intimately united, with the lower wall of
the utricle; anteriorly it is broad, posteriorly narrowed. The
macula acustica neglecta is attached to the roof of the vesicle and
consists of an anterior heart-shaped and a posterior semilunar
portion united by a narrow connecting piece (Fig. 250 III and VII).
The ramulus neglectus divides into two branches, which supply the
two parts of the macula, On the macula acustica neglecta rests the
membrana. tectoria (Deiters) ; the membrane is S-shaped, with the
anterior end narrow, the posterior broad (Fig. 250 VII); the borders of
the membrane are pierced by numerous small round holes, the central
part has smaller and fewer perforations, and is finely striated.
From the middle of the posterior part of the upper surface a thicker

portion projects downwards into the cavity of the pars neglecta; it —

has a narrow, deep notch for the nerve at about its middle; ante-
riorly it points towards a sickle-shaped piece, which is curved in-
wards. Canals run obliquely downwards and inwards from the
apertures on the superior surface.- The membrane is clear, homo-
geneous, partly finely striated, and corresponds with the membrana
tectoria of the pars basilaris, ete.

(8) The lagena cochleae (Figs. 247, 248, and 249 7) is an oval
swelling of the membranous labyrinth ; it lies close to the sacculus
with its broader end forwards, the narrower directed backwards.
By a large rounded opening at the posterior end it communicates
with the saccule by means of a rounded space common to the dagena
cochleae and the cochlea. The papilla acustica lagenae (pl) is situated
in the posterior wall of the /agena ; it is elongated, oval, and supplied
by the vam. lagenae. The papilla is covered by a plate-like otolith
formed of numerous rounded particles.

(9) The pars basilaris cochleae (Figs. 247, 248, and 249 pd) is
placed on the posterior thickened wall of the saccule and lies above

ooncop yeast lM ARMM 0a a

THE EAR. 401

and behind the Zagena. It forms a small, oval, pocket-like protu-
berance, with the long axis directed from in front and above, back-
wards and outwards, its opening being directed forwards and

The membranous labyrinth of Rana esculenta ; after Retzius.

I. Transverse section of the anterior ampulla. Magnified 50 times.

Il. Piece from undersurface of the cupula from the anterior ampulla. Vérick’s Syst., Obj.VIIT, Oc. 3.
III. The macula acustica neglecta, seen from below. Vérick’s Syst., Obj. IV, Oc. 3.

IV. Part of wall of the anterior ampulla.
, V. Part of the cochlea, the pars basilaris cut longitudinally. Vérick’s Syst., Obj. I, Oc. 3.
av VI. Longitudinal section of the pars basilaris. Vérick’s Syst., Obj. I, Oc. 3.
Te VII. The macula ac. neglecta, seen from below. Vérick’s Syst., Obj. IV, Oc. 3.
VIII. The pars basilaris, seen from behind and the outer side. Vérick’s Syst., soni. I, Oc. 3

IX. Transverse section of the external ampulla. Magnified 175 times.

- Oval opening into sacculo-cochlear space. n Nerve-fibres.

Crista acustica. p) Pars basilaris.
cu Cupula terminalis. pe’ Area of coarsely granular cells.
dp Ductus perilymphaticus. ppb Papilla acustica basilaris.
mb Section of thinner wall of pars basi- r _ Epithelium on raphe.

laris. rb = Ramulus basilaris.

mt Tectorial membrane. rn Ramulus neglectus.
mw Thickened membranous wall. itv Tegmentum vasculosum.

. outwards. The short ram. Lasilaris passes in from above to supply
| it. The walls of this dilatation are thick and stiff, with the exception
pd

402 {HE SKIN AND THE SENSE-ORGANS.

of a small portion, the membrana basilaris (Hasse) (mb), which closes
the opening into a small dilatation on the anterior inner wall. The
ramulus basilaris (rb) divides into, at least, two branches, and passes
close to the membrana basilaris (mb), where the elongated and
oval papilla ac. basilaris (Fig. 250 ppb) is placed. The papilla
is covered by a membrana tectoria (Fig. 250 mt), which is often
found separated from the papilla, probably by the action of the

Preparations from the ear of Rana esculenta ; after Retzius.

I. Part of the membranous wall seen from the surface. Vérick, Obj. VI, Oc. 3.
Il. Transverse section of the membranous wall. Vérick, Obj. III, Oc. 3.
Il. Epithelium from the neighbourhood of the macula ac. rec. utriculi. Vérick, Obj. III, Oc. 3.
IV. Branched cells from the yellow spot on the floor of the anterior ampulla. Vérick, Obj. III,

Oc, 3.
Y. Epithelium from the roof of the anterior ampulla. Vérick, Obj. III, Oc, 3.
re Epithelium of raphe. pe Protoplasmic cells,
e Pavementepithelium. . pg Perilymphatic tissue.

reagents used. The form of this membrane is peculiar but will
easily be understood from the figure (Fig. 250 mt). In structure
it is similar to the corresponding structures found in other parts
of the ear.

(10) The tegmentum vasculosum (Deiters) (Figs. 245, 248, and
250 tv) is an oval, shell-shaped dilatation of the membranous laby-
rinth ; its long axis is directed from above and_in front, downwards
and backwards. The walls of the ¢egmentum are thin and inti-
mately attached to the periosteum.

e. The minute structure of the membranous labyrinth (Figs.

251, 252).

s. :
%

Ee

THE EAR. 403

(1) The walls of the membranous labyrinth have the same
general structure throughout: the walls are usually thicker at
the nerve terminations, in the ampullae, semicircular canals, pars
neglecta, and especially the pars basi/aris ; the wall of the ¢egmentum
tympani are the thinnest. The walls are transparent, homogeneous,
refractive, and, at places, show a faint striation, which is, as a rule,
not due to the presence of fibres ; in parts of the recessus utriculi,
and in the outer wall of the saccu/e, especially near the /egmentum
vasculosum, more or less distinct fibres can be made out. Sections
of the wall show spindle-shaped cells, with the processes usually
arranged parallel to the surfaces; seen from the surface, the cells
are seen to branch in all directions (Fig. 251 I, Il). Im the
thinner parts of the walls the cells are few or altogether absent.
The outer surface of the membranous labyrinth is uneven, in conse-
quence of the attachment of the perilymphatic network. Blood-
vessels are also attached to the outer surface, and pierce the wall,
especially near the nerve-terminations.

The whole of the inner surface is lined with a layer of polygonal,
tesselated epithelium-cells. The size and height of the epithelium
varies in different parts. On the outer wall of the saccule the cells
are large, but on the inner wall small; they are also large in the
semicircular canals, except on a small raphe on the inner and outer
side, where they are smaller but higher (Fig. 251 re); in the am-
pullae the cells are large, except on the roof. In the utricle and
sinus superior they are also moderately large. In addition to the places
mentioned, a smaller epithelium is found on the floors of the am-
pullae, in the recessus utriculi, and near all the nerve-terminations
and on the sides of the ampullar septa. Surrounding the nerve-
terminations of the macula rec. utriculi, macula sacculi, and papilla
lagenae are found narrow, branched, yellowish cells (Fig. 251 pe)
with spindle-shaped nuclei. Cells of a third kind, first described
by Deiters, Hasse, and Kuhn, in the tegmentum rasculosum, and in
the ampullae by Hasse and Kuhn, are also found in the utricle.
They contain a yellowish pigment, and are collected into two
sharply differentiated groups in each ampulla (Hasse has one placed
before and one behind the septum on the floor). The cells are
cylindrical, the upper parts striated, the lower narrower, and the
bases again widened to a polygonal, more homogeneous plate,
which is fixed to the wall. On the fegmentum vasculosum the corre-
sponding cells are not so high.

(2) The nerve-terminations. The larger branches of the auditory

pd2

404 THE SKIN AND THE SENSE-ORGANS.

nerve contain medullated fibres of various dimensions and bipolar,
spindle-shaped ganglion-cells. The nerves pierce the walls obliquely
or vertically, and retain their medullary sheaths until near their
final distribution. On each of the nerve-terminations is found
nerve-epithelium, which varies in height in different parts. In the
crista acustica it measures 0°075 mm. in height in the middle part,
o'06 mm. at the sides; on the macula rec. utriculi o'og mm., on the
macula sacculi 0°075 mm., on the papilla lagenae 0:06 mm., on the .
papilla part. basil. 01045 mm., on the macula neglecta o'075 mm.
The epithelium is of two kinds, hair-cells and sustentacular cells.

Fig. 252.

The nerve-terminations in the membranous labyrinth of Rana esculenta ; after Retzius.

I. Vertical section through the crista acustica of the anterior ampulla. Vérick’s Syst., Obj. ITI,

Oc. 3.
II. Vertical section through the macula ac. recessus utriculi. Vérick’s Syst., Obj. VIII, Oc. 3.

III. Three isolated hair-cells from the crista ac. of the anterior ampulla. Vérick’s Syst., Obj. VIII,
Oc. 3.

IV. Two isolated sustentacular cells from the crista ac. of the anterior ampulla, Vérick’s Syst.,

Obj. VIII, Oc. 3.

cr Crista acustica.

cu Cupula terminalis.

Jz Sustentacular cells.
h Hairs of hair-cells.

hz Hair-cells,

n Nerve-fibres.

a. The hair-cells (Fig. 252 4z) have, on the whole, elongated,
flask-like forms, but are not all of the same length (0°024—-0'04 mm.).
The free ends of the cells are rounded, flattened, and yellowish, and
each bears a stiff cilium, which is fixed by a broad base to the cell,
and thins out towards its free end : the cilia vary in length ; in the
ampullae their greatest length is 0°13 mm., on the macula rec.
utriculi o°011 mm., and on the papilla lagenae o'017 mm. The

THE EYE. 405

cells are granular, possess rounded oval nuclei, and are fixed by a
fine, narrow process (Fig. 2 52 hz), though they usually seem to $5
rounded off without possessing a process.

' p. The sustentacular cells. Under the hair-cells is a finely
granular substance, possessing numerous rounded oval nuclei, which
are placed in superimposed rows (Fig. 252 fz), the deepest row
being placed close together and immediately on the membranous
wall. After proper treatment and isolation these nuclei are seen to
belong to narrow, elongated cells, which rest by a slightly widened
base on the wall, and are continued upwards between the hair-cells
to reach the surface of the epithelium, where their upper processes
are again slightly widened.
iH The nerve-fibres (Fig. 252 ) lose their medullary coats, ascend
towards the epithelium, and frequently divide to form two unequal
branches, which ascend to the level of the hair-cells, and curve so as
to course horizontally as extremely fine varicose fibrillae ; these fre-
quently form a network, of which the exact method of termination
has not been made out. In some cases'a fine fibril may be traced
to the base of a hair-cell, but a direct continuation of the one into
the other has not yet been traced.

VL THE EYE.
(Re-written by the translator.)

The organ of sight, the eyeball (ulbus oculi), together with its
appendages (¢utamina oculi), will be described in this chapter.

A. The Eye is flattened on the outer surface, more convex on the
inner or deeper surface. Its principal axis is directed from behind,
forwards and outwards.

The outer transparent portion of the eyeball is the cornea, which
forms the outer boundary of the anterior chamber. The larger, white,
opaque, and inner portion is the sclerotic coat, which, together with
_ two deeper tunics, the choroid coat and the retina; enclose the posterior
chamber of the eye. The pigmented ring placed’ behind the cornea
is the iris, and the aperture it encloses the pupil. The lens is placed
immediately behind the iris. On the inner side the optic nerve
pierces the sclerotic to enter the eyeball.

a. The sclerotic coat (sclerotica s. sclera) forms about three-

406 THE SKIN AND THE SENSE-ORGANS.

fourths of the surface of the eyeball; posteriorly it is pierced by the
optic nerve at a point (yorus opticus) nearer the temporal side than the
nasal. The sclerotic coat consists of fibrous tissue externally, with a
layer of hyaline cartilage internally (Helfreich). The fibrous layer
Fig. 253. is formed of bundles of parallel fibres, which cross
each other, chiefly at right angles (Hoffmann).
The cartilaginous layer ends just behind the line
of insertion of the extrinsic muscle of the eye,
and is thickest at the point of entrance of the
optic nerve (Helfreich).
The sclerotic coat is rich in nerve-fibres, which
Endothelium fromtn, form a close network; the fibres, however, do
sclerotic coats after not unite but form the meshes of the network
by simply crossing each at acute angles.
The deeper surface of the sclerotic coat is lined with a layer of
large endothelial cells (Hoffmann), (Fig. 253), which form the
outer wall of the capsule of Tenon.

b. The cornea and the anterior chamber. The cornea forms
about one-fourth of the surface of the eyeball and is directly con-
tinuous with the sclerotic. In it five layers can be distinguished :
a layer of stratified epithelium or conjunctiva, an anterior hyaline
membrane, the true corneal substance, a posterior hyaline membrane,
and a layer of endothelium.

(1) The corneal epithelium is a layer of stratified epithelium
covering the superficial surface of the cornea. The superficial

layer forms a beautiful mosaic of polygonal cells; the middle

layers are polygonal in all sections, while the deepest layer is more
or less columnar. Except in the most superficial layer, all the cells
have serrated surfaces. Smaller cells possessing each two nuclei
are also found between the columnar cells, and are evidently cells in
process of division ; according to Waldeyer, cell-proliferation may
also take place in the middle layers. ;

The basal or deeper portions of the columnar cells possess a clear
border, which reminds one of the hyaline border found on the free
border of columnar epithelium in other parts. The cells are here so
closely applied to one another that these borders have the appearance
of a continuous, highly refracting membrane (Rollett); according
to Henle, the border consists of a network of very fine processes from
the cells above.

(2) The true corneal substance, and (3) the anterior hya-

|

4
3
.
s
.
+
7)

.
rt
t

THE EYE. 407

line membrane. The corneal substance consists of flat bundles
of fibres arranged in laminae, with cement-substance and connec-
tive-tissue corpuscles interposed. The fibrils are extremely fine
(o‘c00r mm., Engelmann), and bound together into bundles by
cement-substance. The bundles of the laminae are arranged at
various angles, though many are placed at right angles to each
other (Waldeyer).

Between the laminae are flattened spaces, which seen in section
are pee tape. By proper treatment they are seen to be irreg-

Fig. 254. ular, branched spaces,

e which communicate

_— ae by fine canals and

z Be z form part of the Reck-

linghausen-canals_ or
lymph-system. These
spaces contain branch-
-----— ed, connective-tissue
---— corpuscles (Toynbee),
} and a colourless fluid.

The corpuscles (Fig

254 e) do not fill the
spaces which they

Preparation from cornea of Rana esculenta; after Klein, | occupy. They possess
Hartnack’s Syst., Obj. VII, Oc. 3. large nucl. ei, sur-

a Nerve of first order.

© Rate if wasded coder: rounded by granular
Nerve of third order.

a Nerve af fourth order. protoplasm. ,

€ Corneal corpuscles. The canals by which

these spaces communicate (‘ Saftcanalchen ’ of Recklmghausen) lie,
in general, parallel to the surfaces of the cornea, and communi-
cate by joming at acute angles or by short transverse branches.
According to Lavdowsky, these canals have a distinct linmg
membrane.

The anterior hyaline? layer (Bowman’s or Reichert’s lamella) is
not so well seen in the frog as in some higher animals; it is simply
a portion of the corneal substance, of somewhat denser structure
than the rest, nto which it passes by a gradual transition.

(4) The posterior hyaline membrane (Descemet’s membrane)
is a highly elastic, very transparent layer, placed behind the
true corneal substance ; in the frog some few bundles of fibres

* Tamanscheff and Schweigger-Seidel consider the anterior and posterior hyaline
membranes to be composed of fine fibrils.

408 THE SKIN AND THE SENSE-ORGANS,

belonging to the true corneal substance appear to pass into the
posterior hyaline layer, although they cannot be traced further
through its substance. .The structure of the membrane is, in con-
sequence of its transparency, unknown, though the above ob-
servation seems to point to a fibrillar origin.
(5) The corneal endothelium is a single layer of sdisaea
cells of 0-02 mm. diameter. The cells possess the power of altering
"Fig. agg. their shape when stimulated
(Klebs).

cornea are derived from the
ramus ophthalmica trigemint ;
they pierce the sclerotic
coat in front of the scle-
rotic cartilage and then
course towards the cornea,
at the margin of which they
form a coarse network of
medullated fibres. From
this about thirty nerves pass

Preparation from cornea of Rana esculenta ; after towards the cornea. which
Klein. Hartnack’s Syst., Obj. X immers., Oc. 3. : ;

a Endothelial cells. they enter, and then very
b Nuclei of endothelial cells. : quickly lose the main part
ce Nerves of third order in the tissue of the cornea f

propria. of their medullary sheaths.

d Nerves of the fourth order,

According to Wolff, a por-
tion of the nerves retain their medullary sheaths, or in some cases
appear to regain it after having lost it.

The nerves passing from the plexus (nerves of the first order,
Klein) give off smaller branches, which for a short distance have a
serpentine or rectilinear course. By a few anastomoses they form
a loose plexus (nerves of the second order, Klein). After a longer
or shorter course they give off numerous lateral fibres, or termi-
nate in several such fibres arising at one point (nerves of the
third order, Klein). These are distinguished by their size, varying
only within small limits, and by the possession of more or less
regularly placed varicosities; the clearer portions are longitu-
dinally striated as though made up of fibrillae; they have a
nearly rectilinear course, and, after a longer or shorter course,
turn into a direction which is at right angles to the former
one; lastly, they remain for long distances unbranched. These
nerves are connected one with another by cross fibres running at

(6) The nerves of he:

bol .
7, ~~’) oy

THE EYE. 409

right angles to them, and in this way a rectangular trellis-work is
formed.

The fibrils (nerves of the fourth order) given off by these nerves
form networks around the connective-tissue corpuscles, but no
direct connection between nerve and corpuscle has been traced ;
they always appear to lie on that surface of the corneal corpuscle
which is directed towards the superficial surface of the cornea
(Klein). In the endothelium covering the membrane of Descemet
these fibrils can be traced coursing along the margins of the cells
- (Fig. 255 @), and sometimes undergoing dichotomous division
_ Almost all observers have described these fibrils as possessing
varicosities; Hulke, and more recently Wolf, however, deny their
presence. Lavdowsky traces nerve-fibrils to the -nuclei of the
connective-tissue corpuscles.

(7) The anterior chamber is the space between the cornea and
the iris, and is filled with a watery fluid, the aqueous humour. At
the circumference of the chamber are a number of spaces (spaces of
Fontana), formed by interruptions in the tissue between the poste-
rior surface of the cornea and the iris; the result is that bands or
trabeculae (ligamentum pectinatum iridis) pass from the one structure
to the other, and between these are the spaces of Fontana.

According to Angelucci these trabeculae are of three kinds:
trabeculae passing from the cornea to the iris, formed of con-
nective-tissue ; trabeculae from the cornea to the ciliary processes,
which contain elastic tissue ; trabeculae from the interstitial con-
nective-tissue of the ciliary muscle to the cornea, and formed
almost entirely of elastic tissue.

At the junction of the cornea and sclerotic, and just in front of the
spaces of Fontana, is a larger and similar space, which may be traced
round the whole circumference of the cornea; this, the canal of
Schlemm (Siaus cireularis iridis), is held to be a venous plexus by
some observers (Angelucci, and others), according to others it is a
lymphatic space in connection with the anterior chamber (Schwalbe,
and others), It is certain that the vessels can be very easily in-
jected from the anterior chamber, although a direct communication
has not yet been seen.

ec. The choroid coat and the iris (tunica choroidea et iris, tunica
vasculosa).

1. The choroid coat lines the deeper surface of the sclerotic
coat, but is also prolonged under the cornea to form the iris.

410

\,, Are i
TTT ET |
y

|

s

THE

il

SKIN

AND THE

Fig. 256.

SENSE-ORGANS.,

nn i i i

THE EYE. 411

The choroid is firmly attached to the sclerotic in two positions, at
the point of entrance of the optic nerve, and at the line of junction
of the sclerotic and the cornea. Its external surface is closely
applied to the deeper surface of the sclerotic, from which it is only
separated by a very narrow serous cavity (supra-choroidal space),
and to which it is attached by numerous vessels and nerves. The
deep surface of the choroid is covered by the retina, to which it
is closely attached, except at the ora serrata, the attachment being
especially intimate at the processus ciliares.

The choroid coat consists of a fibrous layer containing corpuscles
and traversed by a very rich vascular anastomosis. The corpuscles
of this layer are deeply pigmented, in some cases to such an extent
that the oval nucleus cannot be seen ; the fibrous tissue is also pig-
mented, and has consequently a brownish tinge. That portion of
the layer immediately below the sclerotic is termed the /amina fusca
or suprachoroidea, the vessels on the deeper surface forming ‘the
membrana choriocapillaris. This again is lined on its deeper surface
by a hyaline membrane.

a. The arteries (Fig. 256 VI, VII, VIII) supplying this coat
are two branches of the arteria ophthalmica ; these form a -capil-
lary network (Fig. 256 VII) resembling the corresponding struc-
ture found in mammals. The meshes have approximately the
same size, while the capillaries themselves vary considerably in size.
This network is, however, only complete on the nasal, temporal,

Fig. 256.

The vessels of the choroid and iris ; after Hans Virchow.

I. The two roots of the V. bulbi superior. Magnified 10 times.

II. Vessels of the iris. Magnified 9 times.

III. Origin of the ventral vein.

IV. Schema of the choroid vessels ; seen from the proximal pole.

V. Transverse section through the choroid at the equator.

VL The origin of the choroid arteries from the ophthalmic artery. The greater part of the
sclerotic has been removed. Left eye twice natural size. A. From the proximal pole.
B. From the temporal side.

Ix. The V. ophthalmica and V. bulbi superior on the sclerotic of the right eye. A. Seen from
phi is ress BS ee one. Twice natural size.

A Art. R Branches of the circulus iridis jor,

A’ Art. choroidea. Rd Deinons at wath of under ptiten afuen.
An RB. nasalis of the ophthalmic artery. Rd’ Distal root of nasal vein.

At R. temporalis of the ophthalmic a Rd” Proximal root of nasal vein.

ch Area of membrana Rp’ Nasal root of ventral vein.

Ie Outer pigmented layer of choroid. Rp” Temporal root of ventral vein. .
Li Inner pigmented layer of choroid. Vts_ V. bulbi superior.

N= Optic nerve. Fa Nv. bs era

sue Ve
yr Transitions) pare betwee Seecaeep eis Vp. — root of vein of under surface of
Vs’

r” — Transitional part between choriocapillaris Nasal root of V. bulbi superior.
and upper whorl. Vs” Temporal root of V. bulbi superior.

412 THE SKIN AND THE SENSE-ORGANS.

and proximal part of the upper surfaces. Towards the corpus
ciliare the meshes become wider and elongated ; the capillaries then
unite at acute angles parallel with the longitudinal axis of the
eye. The network (choriocapilaris) exists in a simple layer within
the two arteries which form it, and superficial to the veins (Virchow).

8. The veins of the choroid (Fig. 256 III, IV, IX) are (1) a vein
which unites at the lowest point of the equator of the eye with the
V. hyaloidea to form (2) the V. ophthalmica, two small branches of the
V. bulbi superior, which unite outside the sclerotic, and (3) the vasa
recta,

(1) The larger vein arises from the greater part of the under
surface of the eye ; it gives off branches to each side, which radiate to
form a ‘whorl’ or star-shaped capillary anastomosis (Fig. 256 IIT),
the two halves of which have no connection. A proximal and a
distal root can be distinguished in the anastomosis; the distal lies
towards the corpus ciliare, and occupies exactly one-fourth of the
circumference of the choroid at its junction with the corpus ciliare.

(2) The two branches of the /. bu/bi superior lie alongside the
corpus ciliare on the upper surface, and each occupies one-fourth
of the circumference ; they form a similar though simpler figure
(Fig. 256 I) to the foregoing, each forming one half.

(3) The vasa recta are numerous parallel vessels which arise in the
iris, and coursing centrally empty themselves into the branches of
the V. bulbi superior on the superior surface, and into the branches
of the venous capillaries on the inferior surface.

2. The iris is covered anteriorly by a layer of endothelium,
continuous with that covering the posterior surface of the cornea,
and of similar character. The border of the pupil (margo pupillaris)
is of a golden colour, outside this bright rig to its outer margin
(margo ciliaris) the iris is black ; the golden colour is due to the
presence of cells containing a pale yellow pigment; the nuclei of
these cells are round and granular; the cells themselves have
rounded outlines (Hoffmann). The black portion of the iris con-

tains more irregular, spindle-shaped cells, with round nuclei, which .

are hidden by a dense mass of pigment-granules (Iwanoff and
Hoffmann).

The true substance of the iris consists of muscle, nerves, blood-
vessels, and a connective-tissue stroma, but on the posterior surface
is another layer of black, pigmented cells, and this is again covered
with a hyaline membrane, in which, however, a fibrous structure
may be made out (Koganei).

OR

THE BYE. 413

The muscle-fibres are long, spindle-cells, which are abruptly
swollen in the middle, where the nuclei are situated; the nucleus is
oval, o-oog-0'0012 mm. in length, o-0025 mm. broad, and occupies
nearly the whole of the swollen part of the cell (Hoffmann,
Griinhagen).

According to Koganei the iris possesses a Mf. constrictor iridis (7. ¢.
Berlin Sitzungsber.), but no VW. di/atator iridis ; in a former publica-
tion (7.c. Arch. mik. Anat.) he was unable to find any muscular
fibre, and holds the muscle-fibres of Griinhagen to be connective-
tissue elements.

The stroma consists of delicate connective-tissue fibrils, enclosing
a very large number of pigmented, branched cells.

a. The arteries of the iris (Fig. 256 II) arise from an arch (see
Vessels of Eye) formed by the A..ophthalmica in the corpus ciliare.
It commences between the ventral and temporal surfaces by two
branches: one courses along the temporal border, the other along
the nasal, to meet each other on the nasal surface; the former
courses through one-third, the latter embraces two-thirds of the
circumference at the iris.

The temporal artery courses along the ciliary border during the
first third of its course, it then gradually approaches the border of
the pupil; the nasal artery runs at once towards the pupil. On
the nasal border of the pupil they anastomose by their branches,
and so form a circulus iridis major.

Except near their termination, no small vessels arise from this
arterial circle ; in Fig. 256 II, for example, only five larger branches
are given off, three from the temporal side and two from the nasal.
The five large branches run towards the circumferential border of
the iris and break up into numerous vessels, which form a very
irregular and open network. From this network arise the vasa
recta already described.

d. The lens is almost spherical, and is composed of cellular ele-
ments enclosed in a capsule (capsu/a lentis).

The capsule is a homogeneous, transparent, structureless, and
highly elastic membrane. The deeper surface of the anterior cap-
sule is lined with a simple layer of regular nucleated six-sided
epithelial cells.

The lens itself consists of long, flat fibres ; seen from the surface
these are broad, narrow edge-wise, and in section six-sided prisms.
Those lying parallel to the anterior and posterior surfaces are

414 THE SKIN AND THE SENSE-ORGANS,

broad and thicker, those towards the border are narrower. These
cells are striated, both longitudinally and transversely (Arnold).
The cells near the margin, however, have no transverse striation
(Hoffmann). The cells of the central parts form a much closer and
firmer structure than those at the periphery (Arnold). The peri-
pheral cells are nucleated, and sometimes even possess two nuclei to
one cell ; the central cells have no nuclei (Arnold).

The cells are held together by a cement-substance and by their
serrated surfaces; the serrations are the cause of the transverse
striations. The fibres of the lens have a simple arrangement : com-
mencing at the middle point or pole of one surface they pass over
the equator to the opposite pole; consequently the long borders of
adjacent cells are in juxtaposition, and their pointed extremities
meet at points in the axis of the lens (Hoffmann).

Ritter has described short, nucleated cells in the centre of the
lens; these are held by Babuchin to be cells which have been
arrested in their development.

e. The retina is the innermost coat
of the eye; in the recent state it is
= 22m pale, soft, and smooth. The structures
WIA — composing it are arranged in ten
layers; from the deeper surface
towards the choroid these are: the
internal limiting membrane, the
optic-fibre layer, the ganglion layer,
the inner molecular layer, the inner
nuclear layer, the outer molecular
- layer, the outer nuclear layer, the

~- external limiting membrane, the layer
Mibtvs from the fens of the frog; after of rods and cones, and the pigment
Se ae mann. Magnified 700 times, layer.

These layers are held together by connective-tissue elements.

(1) The internal limiting membrane (Membrana limitans in-
terna) will be described together with the connective-tissue ele-
ments (10).

(2) The optic-fibre layer is formed by the fibres of the optic
nerve. The nerve-fibres in their course towards the eye are
possessed of medullary sheaths, but on piercing the sclerotic these
sheaths are lost. The fibres are now pale, non-medullated, and of
_ very varying thickness. In the mass of fibres nothing can be seen
except an extremely fine fibrillation and very fine varicosities ; the

a

——

THE EYE.

415

latter, however, appear to be artificial productions (Hoffmann):
Fig. 258.

This layer of fibres extends over the inner
surface of the retina, and gradually thins
from the point of entrance of the optic
nerve to the limits of the retina.

(3) The ganglion-layer lies immedi-
ately without the nerve-fibre layer (Fig.
2584). The ganglion-cells are small and
usually pear-shaped. The cells possess
large nuclei, round which is a thin layer
of very granular protoplasm. The cells
have inner and outer processes ; the inner
pass into the nerve-fibre layer, the outer
into the inner molecular layer in more or
Tess radiating directions. Manz claims
to have traced a direct connection between
the inner processes and the fibres of the
nerve-fibre layer.

Each ganglion-cell, whatever its shape
or size, has only one inner process, which
is easily distinguished from the outer
process by its being more glistening, by
the possession of varicosities, and because
this process never branches, _

The outer processes are single(Schwalbe)
or rarely double (Hoffmann), and have as
a rule a direction at right angles to the
inner processes. Each outer process is
finely granular, which suggests rather a
prolongation of the cell-substance than
a true process. Frequently they are
branched, sometimes forming two equal
sized processes, which give off finer
twigs; at other times they appear to
pass through the whole of the inner
molecular layer without undergoing di-
vision (Schwalbe). The processes do not
inosculate (Santi Sirena).

(4) The inner molecular layer (Fig.

Vertical section through retina of

ye Fens an oe

frog; after Hoffmann. Magni-
fied 5co times.

Internal limiting membrane, »’

Ganglion-cell Jayer.

Internal molecular layer.

Internal nuclear layer.

External molecular layer.

External miiclear layer.

Layer of rods and cones.

Pigmented epithelium layer.

Immer segments of reds and
cones.

Quter segments of reds and
cones,

. Outer transparent segments of

- ~ pigmented epithelium,

258 c) is 0'07-0'08 mm. thick (Hoffmann), and consists of a finely ~

416 THE SKIN AND THE SENSE-ORGANS.

granular mass together with the outer processes of the ase
layer, and connective-tissue elements.

The granular matter consists of an extremely fine network or
reticulum, through which numerous fine fibres course (Schultze,
Kélliker, Manz, Heinemann, and others); according to Schultze
the supposed molecules or granules of others (Henle, Merkel, and
Retzius) are simply the fine meshes of this reticulum. The
branched, outer. processes of the ganglion-cells form a rich anas-
tomosis in this layer.

(5) The inner nuclear layer (Fig. 258 @) contains parts’ of two
kinds of cellular elements ; these are radial nerve-fibres with large
nuclei, and connective-tissue elements (see below, par. 10). The
nerve-fibres are easily distinguished by their spindle-shaped vari-
cosities ; both cellular elements possess large oval nuclei. The
bodies of the cells surrounding the nerve nuclei are almost filled
by the nuclei, which have sharply-defined, rounded nucleoli. The
fibres to which these cells are attached may be distinguished as
inner and outer processes ; the inner process is fine, irregularly vari-
cose, and unbranched ; the outer process is thicker, finely granular,
and is not varicose (Schwalbe). At the margin of the outer mole-
cular layer the outer processes divide, usually into two branches,
and at an acute angle to each other, though sometimes at a right
angle. The further course of these branches in the outer molecular
layer is unknown.

(6) The outer molecular layer (Fig. 258 e) corresponds in
general with the inner molecular layer as regards its structure ; it
is, however, much thinner.

(7 and g) The outer nuclear layer and the layer of rods and
cones (Figs. 258 f, g, 259). ‘The rods and cones are intimately
connected with the elements of the outer nuclear layer, hence the
two layers are best described together.

The rods (aci//:) have two parts or limbs, an outer and an inner,
which differ in structure, and in chemical and physical characters.
The outer part is highly refractive, the inner more homogeneous
and less refractive, the two parts being sharply differentiated from
one another.

The outer part is also weakly doubly refracting, the inner has no
trace of this property. The rods are 0'05-0'06 mm, in length, of
which 0°035-0'04 mm. belongs to the inner limb. The outer
end of the outer limb is more or less rounded ; the whole has a
longitudinal striation (Schultze), due to its being composed of

THE EYE. 417

rounded fibrils, about twenty-four to each rod (Hensen). The
fibrils are sharply differentiated from each other and have a slightly
spiral course; when seen in transverse section these outer limbs

Fig. 259.

do not appear to be round
(Schultze), although
others hold them to
be perfectly rounded
(Hoffmann and others),
and that the loss of
the cylindrical form is
due to the methods of
treatment. According
to Merkel the longitu-
dinal striation is caused
by a canalisation of the
outer limb, which ae-
cording to him encloses
the processes of the pig-
mented epithelial layer ;
he is also of opinion that
the spiral appearance is
an artificial product. In
the latter opinion he is
probably wrong, as per-
fectly fresh rods exa-
mined in aqueous humour
show the same spiral
appearance (Hoffmann) :
against the canalisation
view others observe that
the longitudinal stria-
tion is most distinct near
the inner limit of the
outer limb, and that it
is impossible to conceive
that the processes of
the pigment-cells should

Various preparations from the eye of the frog:
chiefly from the retina.
1. Rod from retina in aqueous humour, showing spiral
striation.
2. Three rods and one cone after treatment with osmic acid.
3, 4, 5- Rods examined in recent state.
6, 7. Inner segments of two rods after treatment with osmic
aci
Outer limb,
Inner limb.
Lenticular body.
Nucleus of outer nuclear layer,
External limiting membrane.
8. Nuclear body from inner nuclear layer.
g. Twin-cone.
ro. Sustentacular fibre of retina.

anecea™

11. Surface view of pigmented epithelium of retina.

12, 13. Isolated pigmented cells of retina.

14. Four pigmented cells, rods and cones, external limiting

membrane, and part of outer nuclear layer attached.

15. Two pigmented cells ; each showing three attached rods.

16. Muscle-fibre from the iris.

Figs. 1, 2, 3, 4, 5, 6, 7, 8, 9 are magnified 500 times. Fig. 10,
300 times. Fig. 16, 400 times. All are copied from Hoff-
mann’s figures.

Figs. 12, 13, 14, 15 are copied from Morano’s figures ; Hart-
nack, Oc. II, Obj. 9.

terminate with such extremely regular ends (Hoffmann),
In the central part of the inner end of the outer limb
is seen a dark point when the structures are examined in trans-

verse section (Ritter, Manz, Schiess, Schultze, and others).

The
Ee

418 THE SKIN AND THE SENSBH-ORGANS.

cause of this is not clearly. understood; some hold it to be a
fibre (Ritter’s fibres), others hold it to be an artificial product
(Hensen). :

After treatment with certain reagents the outer limbs show a
transverse striation, which is probably produced by the action of
these reagents on the sheath of the outer limbs; that a sheath is
present is proved by its possession of a different refractive index
(Zenker, Schultze) to the rest of the outer limb, and this transverse
striation is not seen until the whole organ has undergone consi-
derable post-mortem changes (Hoffmann). Should this change be
allowed to proceed a stage further, the outer limbs of the rods split
transversely and form small discs from 0:0005—0°00055 mm. thick ;
this takes place in the outer limb only.

The inner segments of the rods (Figs. 258, 259) are short (0:020—
0022 mm.) and of the same thickness as the outer limbs. When
perfectly fresh they appear homogeneous; very quickly changes
commence, which are probably due to coagulation. A plano-convex
figure (Fig. 259) is then seen at the outer portion of the seg-
ment (lens-shaped figure of Schultze); with staining reagents it
gives the same reactions as the outer segment of the rods. The
rest of this segment forms a short cylinder, which probably has no
distinct sheath (Hoffmann, Merkel) ; some observers are inclined to
think that a sheath exists (Landolt, Schwalbe).

The outer segments of the rods are of two chief sizes (Schwalbe).
Those of the one kind are large; the second variety occurs less fre-
quently, and the segments are shorter, measuring only 0002 to
070025 mm. ‘The inner segment is a Jong, thread-like process,
except where it is swollen to enclose the lens-shaped body.

The rods are much more numerous than‘the cones, except at one
small spot (macula lutea) on the posterior surface of the retina,
where only cones are found (Krause).

The cones (conz) have each two segments like the rods (Figs. 258,
259). The outer segments are short (4-5 pu), they are slightly
conical and terminate externally in a blunt point ; they possess a
longitudinal striation (Schultze), and very easily break up trans-
versely into small discs, which, however, do not separate so com-
pletely as in the case of the rods, in consequence of the presence of
a sheath continuous with a sheath on the inner segment.

The inner segments (Figs. 258, 259) have convex sides and
measure 12-14 »; like the corresponding parts of the rods they
possess lens-shaped bodies at their junction with the outer segments,

THE EYE. - 419

but the bodies differ in shape, being bi-convex or rather oval in
form. The*inner segments are enclosed in a delicate sheath con-
tinuous with that of the outer segments.

In some cases two cones are united to form a twin-cone ; in such
cases the one is always larger than the other (Fig. 259 9), and has
several peculiarities which distinguish it from the smaller.

The smaller or secondary member of a twin-cone is longer, and
possesses a lens-shaped body which is plano-convex. The larger or
principal member of a twin-cone is shorter, has a plano-convex
body, but also an oval, homogeneous, glistening body, which is
directly attached to the plano-convex body. The shape of the two
members is also different.

The outer nuclear layer (Fig. 258 7) is 14-16 p thick; the
nuclei lie in two layers. The nuclei belonging to rods and cones
have the same characters, each nucleus being a large, oval, hyaline
body, and enclosing a bright nucleolus. Each nucleus is surrounded
by an extremely thin layer of finely granular matter. The inner
processes of the nuclear bodies both of the rods and the cones extend
to the outer molecular layer, are there dilated and serrated, where
they become attached to the outer molecular layer (Schultze, Hoff-
mann). In some cases, however, the inner process of the nuclear
bodies, belonging to the rods, forms only a short fine fibre.

In the case of twin-cones the corresponding parts in the outer
nuclear layer possess two nuclei (Schultze).

(8) The pigment layer (Figs. 258 4, and 259 11, 12, 13, 14, 15)
is not intimately attached to the rest of the retina. It consists of
eylindrical cells in which two parts or segments are sharply diffe-
rentiated ; the external part, directed towards the choroid coat, is
of pale, or colourless granular protoplasm, and occupies one-third
of the length of the cell; this part encloses a large, round, nucleo-
lated nucleus. This colourless segment of the cell also includes
one or two bright yellow, fat globules (Morano). Seen from the
surface the cells are hexagonal (Fig. 259 11). The remaining
two-thirds of the cells consists of a brush formed of numerous fine
pigmented processes; the ultimate terminations of the processes,
which lie parallel to each other, are frequently unpigmented ; each
cell possesses thirty to forty such processes (Morano).

The processes extend between the rods and cones as far as the
external limiting membrane (Figs. 258, 259), or sometimes a little
further (Merkel, Morano, Hoffmann). The processes from one
pigment-cell surround a number of rods and cones; according to

: Ee 2

420 THE SKIN AND THE SENSE-ORGANS.

Morano twelve to fifteen rods and cones may be encased or sur-
rounded by the processes of a single cell.

The thickness of this layer varies from 60-70 »; the nuclei of
the cells have a diameter of 10-12 p, the width of a single cell is
from 20-25 « (Hoffmann).

(10) The connective-tissue elements of the retina and the ex-
ternal and internal limiting membranes. The elements of the
retina are supported by connective-tissue elements or sustentacular
cells, which have a radial arrangement, and which form the two
limiting membranes (Miller).

Each sustentacular cell (Fig. 259 10) has two segments, an inner
and an outer, the boundary between these lying in the inner nuclear
layer, and being marked by the presence of a large oval nucleus.
The inner segment of each cell terminates internally in a wide ‘ foot”
or base, or may form several such after having undergone division
(Schultze): these bases together form a transparent, thin mem-
brane, the internal limiting membrane (membrana limitans interna).

Within the ganglion-layer these cells possess peculiar appen-
dages, which fit round the ganglion-cells and support them
(Schwalbe).

The outer segments of the sustentacular cells extend into the
outer molecular layer, and then break up into irregular processes
which extend radially to the external limiting membrane, and
which they probably form. The external limiting membrane
(membrana limitans externa) is therefore a membrane corresponding
to the internal limiting membrane, and formed by the flattened
ends of the processes belonging to the sustentacular cells.

The sustentacular cells have a distinct, resistant cell-wall
(Schwalbe) ; the cell-contents are a finely granular protoplasm, and
a large oval, nucleated nucleus placed in the inner nuclear layer.

f. The ciliary processes have the same structure as the rest of
the choroid coat: the vessels form more or less longitudinal meshes
and are more irregular than in the rest of the choroid.

g. The posterior chamber and vitreous body (Fig. 260). The
vitreous humour occupies the greater portion of the cavity of
the eyeball, 7. ¢. the posterior chamber. The humour consists of a
mass of cells enclosed in a transparent hyaloid membrane (mem-
brana hyaloidea), which is in contact with the internal limiting
membrane of the retina.

The cells forming this structure are small, flattened, transparent,

THE EYE. 421

and nucleated (Iwanoff and Virchow); according to the former
observer the cells have contractile powers.

The hyaloid membrane is described as structureless by Schwalbe,
as fibrous by Pappenheim, Bowman, and Fuikbeiner.

The vessels of the vitreous body (Fig. 260) are as follows. The
A. hyaloidea arises at the lowest point of the corpus ciliare ; it almost
immediately divides into two branches, which form a ring at a
distance of about o-5 mm. from the lens and lying on the surface
of the vitreous body (Fig. 260 I, II). One, 2. nasalis, passes to
the nasal side and courses through one-fourth of the circle; the

| : Fig. 260.

The vessels of the vitreous body ; after Hans Virchow,

I. Vessels of the vitreous body ; seen from the deeper pole and slightly from above. Magnified
6 times. ;
If. ies of the vitreous body of the right eye.
A Seen from the proximal pole.
B Seen from the nasal side.
III, Veins of the vitreous body of the left eye.
A Seen from the proximal pole.
B Seen from the nasal side.
Nasal vein.
Temporal vein.
Branch (constant) of temporal vein.
R. nasalis of the ophthalmic artery.
R. temporalis of the ophthalmic artery.
Termination of the R. temporalis.
V Ventral vein.

other, 2. temporalis, courses through three-fourths of the circle. The
branches are all given off proximally and at right angles to the circle
(Fig. 260 1, Il). From the 2. zasa/is only one branch arises, from
the R. temporalis seven, the first of which corresponds in point of
origin with the branch from the R. zasalis. The branches on the
nasal and temporal surfaces of the vitreous body are the shortest.

avr sacs

sy

422 THE SKIN AND THE SENSBE-ORGANS,

These -branches form a capillary network (Fig. 260 I) with
elongated meshes, formed by the capillaries anastomosing at acute
angles. The capillary network is more dense towards the middle
of the proximal surface than in other parts.

The veins arising from this network are three in number (Fig.
260 III); two of these accompany the arteries from their origin,
and form a somewhat similar circle around the lens, while the third
passes backwards along the ventral surface of the vitreous body to
the papilla nervi opticit. The nasal vein, however, takes a more
proximal course than the corresponding artery, the branches of
which it crosses ; consequently the venous ring is not so perfect as
the arterial. The nasal vein is larger and the temporal vein smaller
than the corresponding arteries.

The ventral vein is formed near the papilla nervi optici by the
union of two smaller branches. The capillary system of these
vessels has the usual structure of capillaries, the cells being united
by cement-substance (Zimmermann).

The blood-vessels of the vitreous body are accompanied by
lymphatics; according to Iwanoff they completely enclose the
capillaries: Zimmerman contradicts this view, as he has been un-
able to find lymphaties on that side of the capillaries directed
towards the vitreous body.

B. Appendages of the eye.

The appendages of the eye are the eye-muscles (see pp. 55-59);

the eyelids, the Harderian gland, and the lachrymal duct.

a. The eyelids are two in number, an upper and a lower. The
upper eyelid is intimately attached. to the eyeball and follows the
movements of that organ.

The lower eyelid (membrana nictitans) is much larger than
the upper and has the same functions as the lower eyelid of higher
vertebrates. It forms a transparent covering for the eyeball, and
is raised by a special muscle (see p. 58); functionally it takes the
place of both eyelids of higher vertebrates.

The lower eyelid is a prolongation of the skin, but has only a
few pigment-cells, except at its free margin, and no serous glands.
Mucous glands are found in two or three rows, closely applied to
one another, on the superficial surface of the lid ; on the deeper surface
they are wanting. The stroma of the lid, like the cutis, is of con-
nective-tissue.

Nerve-fibres can be traced in all directions through the substance

Le ee

THE EYE. 423

of the lid, forming a wide-meshed plexus. Around each gland the
plexus becomes finer and by numerous branchings much closer ; from
the plexus twigs are given off, which divide to form a number of
fibrils traceable into the epithelial cells of the glands (Openchowski).
- The vessels of the lower eyelid have been investigated by Stricker,
(Z..c.); according to him they possess some interesting peculiarities.
Many of these capillaries course within a lymphatic vessel, in
some places the capillary being contracted by a projection from

Fig. 261.

Preparations from the nictitating membrane of Rana esculenta to show distribution of nerves.

I. Preparation of the nictitating membrane to show nervous supply to a capillary vessel ; after
Klein. Hartnack, Oc. III, Obj. 8.
a Capillary vessel.
6 Blood-corpuscles.
candd Non-medullated nerve-fibres.
Il. To show distribution of nerves in the epithelium ; after Klein. Hartnack, Oc. IV, Obj. 8.
° } Subepithelial nerve-fibres.
e Fine fibrils between the deepest epithelial cells.
ad Deepest epithelial cells.

its inner wall; where this is found the accompanying lymphatic
is correspondingly dilated. Such points are especially met with
where the capillaries branch ; in many cases the capillary was con-
tracted to such an extent that the blood-corpuscles were unable
to pass the obstruction. Stricker further observed in the living
tissue that such constrictions could take place in a part which a
short time previously had been comparatively wide and dilated ;
further, that many of the nerves were enclosed in similar lymphatics.
Langer, however (/. ¢.), describes the vessels as being accompanied
by an irregular network of small lymphatic vessels.

The distribution of the nerves in the lower eyelid has been de-
seribed by Klein. In the epithelium they form a network re-
sembling that found in the cornea (Fig. 261 II); along the blood-
vessels the fine fibrils form a “perivascular network, which supplies

424 THE SKIN AND THE SENSE-ORGANS.

fine twigs to the walls of the vessels (Fig. 261 1). He dis-
tinguishes three kinds of pigmented cells.

b.. The Harderian gland is situated at the inner angle of the
eye, and is pear-shaped in form. It consists of a number of
racemose glands held together by connective-tissue, the whole being
enclosed in a relatively thick and strong capsule of connective-
tissue.

The alveoli have a diameter of 0:040-0'060 mm. : they possess a
lining of epithelium and a lumen which varies considerably in size.
The epithelial layer is bounded externally by a membrana propria.
The cells are placed eccentrically, they are cylindrical, and com-
posed of finely granular protoplasm ; each cell contains a pale,
rounded nucleus. The ducts of the alveoli are lined with a
single layer of cylindrical epithelium, the cells of which are usually
shorter and narrower than those of the epithelium of the alveoli ;
the ducts open into a single main tube, lined with similar epithelium
but strengthened externally by a layer of connective-tissue. The
glands secrete a fluid which moistens the free surface of the eye.

The Harderian glands are surrounded by a rich capillary anasto-
~ mosis which completely invests the alveoli.

e. The lachrymal duct opens behind and below into the nasal
cavity (see p. 389), anteriorly it can be traced forwards, as a small
tube imbedded in connective-tissue and lying immediately beneath
the skin, to the outer angle of the eye, where it opens by numerous
tubules,

The lachrymal duet is lined with ciliated columnar epithelium.

- ADDENDA. ee ae

HISTOLOGY OF MUSCLE, CARTILAGE, BONE,
AND THE CONNECTIVE TISSUES.

LITERATURE.

—_o—-

I. MUSCLE AND NERVE-ENDINGS IN MUSCLE.

Arnold, J., Gewebe der organischen Muskeln. Stricker’s Gewebelehre, 1871. Vol. I,
p- 142.

Arnold, J., Ueber die Abscheidung des indigschwefelsauren Natrons im Muskel-
gewebe. Virchow’s Arch. Vol. LXXI, p. 1.

Babuchin, Ueber den feineren und Ursprung des Axencylinders. Centralbl. f. med.
Wiss. 1868, p. 755.

Barfurth, D., Die Riickbildung des Froschlarvenschwanzes und die sogenannten
Sarkoplasten. Arch. f. mik. Anat. 1887. Vol. XXIX, p, 35.

Biedermann, W., Zur Lehre vom Bau der quergestreiften Muskelfaser. Wiener
Sitzungsber. 1876. Vol. LX XIV, Pt. III, pp. 49-62.

v. Biesiadecki, A., and Herzig, A., Die verschiedenen Formen der quergestreiften
Muskelfasern. Wiener Sitzungsber. 1859, Vol. XXXIII, p. 146: and in
Moleschott’s Untersuchungen, 1860, Vol. VI, p. 105.

du Bois-Reymond, E., Ueber facettenformige Endigung der Muskelbiindel. Berlin.
Acad. Monatsber. 1872, pp. 791-814. Abstract in Centralbl. f. d. med. Wiss.
1873. No.55, p- 868.

Bowman. On the minute structure and movements of voluntary muscle. Phil.
Trans. 1840, p. 457-

Bremer, L., Ueber die Endigungen der markhaltigen und marklosen Nerven im
quergestreiften Muskel. Arch. f. mik. Anat. 1882. Vol. XXI, p. 165.

Bremer, L., Ueber die Muskelspindeln nebst Bemerkungen iiber Structur, Neubil-
dung, und Innervation der quergestreiften Muskelfaser. Arch. f. mik. Anat.
1883. Vol. XXII, p. 318.

Calberla, E., Studien tiber die Entwicklung der quergestreiften Muskeln und
Nerven der Amphibien und Reptilien. Arch. f. mik. Anat. 1875. Vol. XI,
p- 442.

Calberla, E., Ueber die Endigungsweise der Nerven in den quergestreiften Muskeln
der Amphibien. Dissert. Freiburg i. B. 1874; also in Zeitschr. f. d. wiss. Zool.
1874. Vol. XXIV, pp. 164-178.

Chittenden, R. H., Histochemische Untersuchungen iiber das Sarkolemm und
einige verwandte Membranen. Untersuch. d. physiol. Instituts d. Universitit
Heidelberg. Vol. III,

Cohnheim, J., Ueber die Endigung der Muskelnerven. Centralbl. f. d. med. Wiss.
1863, p. 865.

Eberth, C. J., Untersuchungen iiber die normale und pathologische Leber. Vir-
chow’s Arch. 1864. Vol. XXXIX, p. 74.

Engelmann, T. W., Zur Lehre von der Nervenendigung im Muskel. Jenaische
Zeitschr. 1868. Vol. IV, p. 307.

Engelmann, T. W., Untersuchungen iiber den Zusammenh. von Nerven u.
Muskelfasern. Leipzig, 1863.

LITERATURE. 427

Engelmann, T. W., Microscopische Untersuchungen iiber die quergestreifte
Muskelsubstanz. Pfliiger’s Arch. 1873. Vol. VII, pp. 33-71, and pp. 155-187-

mpmotmann, T. W., Ueber die Endigung der motorischen Nerven in den quer-

Muskeln der Wirbelthiere. Centralbl. f. med. Wiss. 1863, p. 289.

Ewald, A., Ueber die Endigung der motorischen Nerven in den quergestreiften
Muskeln. Pifliiger’s Arch. 1876. Vol. XII, p. 529.

Ewald, A., and Kihne, W., Die Verdauung als histologische Methode. Heidelb.
naturhistor.-med. Verhiadl: 1877. Vol. I, p. 451.

Exner, 8., Notiz zu der Frage von der Faserverteilung mehrerer Nerven in einem
Muskel. Pfliiger’s Arch. 1885. Vol. XXXVI, p. 572.

Fischer, E., Ueber die Endigung der Nerven im quergestreiften Muskel der Wir-
belthiere. Arch. f. mikrosk. Anat. 1877. Vol. XIII, p. 365.

Froriep, A., Ueber das Sarcolemm und die Muskelkerne. Arch. f. Anat. u. Physiol.
1878, p. 416.

Gerlach, J., Ueber das Verhalten der Nerven in den quergestreiften Muskelfaden
der Wirbelthiere. Sitzungsb. Erlangen. 1873. Vol. V, p. 97; Abstract in
Centralbl. f. d. med. Wiss. 1874, p. 227-

Gerlach, J., Das Verhaltniss der Nerven zu den willkiirlichen Muskeln der Wir-
belthiere. Leipzig, 1874.

Gerlach, J., Ueber das Verhialtniss der nervésen und contractilen Substanz des
quergestreiften Muskels. Arch. f. mik. Anat. 1877. Vol. XIII, p. 399.

Golgi, C., Sui Nervi dei Tendini dell’ Uomo e di altri Vertebrati e di un nuovo
Organo Nervoso terminale Musculo-tendineo. Torino. Estr. dalle Memorie
della Reale Acc. di Torino. Series II. 1880, Vol. XXXII.

-Gritzner, P., Zur Anatomie und Physiologie der quergestreiften Muskeln. Recueil
Zoolog. Suisse, 1884. Vol. I, pp. 665-684.

Haycraft, J. B., Upon the cause of the striation of voluntary muscular tissue.
Quart. Journ. Micros. Soc. 1881. Vol. XXI, p. 307.

Hensche, Ueber die Driisen und glatten Muskeln in der dusseren Haut von Rana

ia. Zeitschr. f. wiss. Zool. 1856. Vol. VII, p. 273.

Hensen, V., Ueber die Entwicklung des Gewebes und der Nerven im Schwanze der
Froschlarve. Virchow’s Arch. 1864. Vol. XXX, p. 51.

Jakimovitsch, Ueber die Regeneration der glatten Muskelfasern. Centralbl. f. d.
med. Wiss. 1879, p. 897.

Key, A., Bidrag till Nervernas andningsatt i Musklerna. Forhandlingar vid
Skandinaviska Naturforskaemétet i Stockholm, 1863. Abstract in Centralbl. f.
d. med. Wiss. 1866, p. 212. (Muscles of frog's tongue.)

Klebs, re Die Nerven der organischen Muskeln. Centralbl. f. d. med. Wiss. 1863,
p- 561.

Klebs, E., Die Nerven der organischen Muskeln. Virchow’s Arch. 1865. Vol.
XXXII, pp. 169-198.

“v. Kélliker, A., Gewebelehre.

v. Kolliker, A., Einige Bemerkungen tiber die Endigung der Hautnerven u. den Bau
der Muskeln. Zeitschr. f. wiss. Zool. 1857. Vol. VIII, p. 311.

Krause, W., Ueber den Bau der quergestreiften Muskelfaser. Zeitschr. f. rat. Med.
Vol. XXIII.

Krause, W., Die Nervenendigungen in den Froschmuskeln. Internat. Monatschr.
1884. Vol. I, pp. 194-203.

Krause, W., Die motorischen Endplatten, ete. Hannover, 1869.

= W., Ueber die Endigungen der Muskelnerven. Gittinger Nachrichten.
1603, Pp. 21.

Krause, W., Ueber die Endigungen der Muskelnerven. Henle and Pfeufer’s
Zeitschr. ‘1863. Vol. XX, pp. 1-19.

Kihne, W., Untersuchungen tiber Bewegungen und Veranderungen der contractilen
Substanzen. Arch. f. Anat. u. Phys. 1859, p. 816.

428 MUSCLE, CARTILAGE, BONE, AND CONNECTIVE TISSUES.

Kihne, W., Die Muskelspindeln. Virchow’s Arch. 1864. Vol. XXVIII, pp. 528-538.

Kihne, W., Untersuchungen iiber das Protoplasma und die Contractilitat. Leipzig,
1864.

Kihne, W., Ueber die peripherischen Endorgane der motorischen Nerven. Leipzig,
1862.

Kihne, W., Zur Lehre von den Endplatten der Nervenhiigel. Virchow’s Arch,
1866. Vol. XXXIV, pp. 412-422.

Kiithne, W., Ueber das Verhalten des Muskels zum Nerven. Verhandl, d. natur-
hist.-med. Vereins zu Heidelberg. 1880. Vol. II, p. 227.

Kihne, W., Ueber Nervenendigungen in den Muskeln nach Beobachtungen von
M. B. van Sykel. Abdruk. aus den Verhandl. d. Naturh. med. Verein zu Heidel-
berg. 1884. Vol. III, pp. 238-242.

Kihne, W., Wiederlegung der Bemerkung E. du Bois-Reymond’s iiber mehrfache.
Nervenendigungen einer Muskelfaser. Zeitschr. f. Biol. 1884. Vol. XX, pp.
531-539-

Kihne, W., Ueber die Endigung der Nerven in den Muskeln. Virchow’s Arch.
1866. Vol. X XVII, pp. 508-533.

Kihne, W., and Voit, C., Neue Untersuchungen iiber motorische Nervenendigung.
Zeitschr. f. Biologie. Wol. XX XIII.

Lavdowsky, M., Die feinere Struktur und die Nervenendigungen der Froschharn-
blase. Arch. f. Anat. u. Physiol. 1872, p. 55.

Leboucq, H., Recherches sur le développement et la terminaison des nerves chez
les larves des Batrachiens. Bull. de l’Acad. de roy. de Belgique. 1876, Vol.
XLI, p. 561.

Letzerich, L., Ueber die Endigungsweise der motorischen Nerven. Med. Centralz.
1863, No. 37.

Leydig, F., Ueber Tastkorperchen und Muskelstructur. Arch. f. Anat. u. Physiol.
1856, p. 150. ;

Léwit, Die Nerven der glatten Muskulatur. Sitzungsb. d. Wiener Acad. 1875.
Vol. LXXT, Pt. ITT, p. 355.

Marshall, C. F., The structure and distribution of striped and unstriped muscle.
Quart. Journ. Micros. Sci, 1887. Vol. XXV.

Martin, H., Sur la structure de la fibre musculaire striée et sur les analogies de
structure et fonction entre les tissus musculaires et les cellules & batonnets
(protoplasma strié). Arch. de physiol. norm. et pathol. 1882, p. 465.

Mayer, S., Die sogenannten Sarkoplasten. Anat. Anzeiger, 1886. No. 9, p. 231.

Mayer, S., Einige Bemerkungen zur Lehre von der Riickbildung der quergestreiften
Muskelfasern. Prager Zeitschr. f. Heilkde. 1887., Vol. VIII, p. 177.

Mays, K., Histo-physiol. Untersuchungen iiber die Verbreitung der Nerven in den
Muskeln. Zeitschr. f. Biol. Vol. XX.

Mays, K., Ueber die Nervatur des Musculus rectus abdominis des Frosches.
Heidelberg, 1886.

Meliand, B., A simplified view of the histology of the striped muscle-fibre. Quart.
Journ. Micros. Sci. 1885. Vol. XXV, p. 371.

Merkel, F., Der quergestreifte Muskel. Arch. f. mik. Anat. 1873. Vol. IX,
pp: 293-367.

Minra, M., Untersuchungen iiber die motorischen Nervenendigungen der querge-
streiften Muskelfasern. Virchow’s Arch. 1886. Vol. CV, p. 129.

Nasse, O., Zur Anatomie und Physiologie der quergestreiften Muskelfasern. Leipzig,
1882. Abstract in Centralbl. f. d. med. Wiss. 1882, pp. 884 and 908.

Newman, D., New theory of contraction of striated muscle and demonstration of
the composition of the broad dark bands. Journ. of Anat. and Physiol. 1879, p. 4.

Nicolaides, R., Ueber die caryokynetischen Erscheinungen der Muskelkérper
wihrend des Wachstums der quergestreiften Muskeln. Arch. f, Anat. u. Physiol.

1883, p. 441.

LITERATURE. 429

_ Odenias, M. W., Undersékungen dfer de sensibla muskelnervena. Nord. Medic.
Arch. Vol. IV, No. 18.

Paneth, J.; Die Entwickelung von quergestreiften Muskelfasern aus Sarkoplasten.
Wiener Sitzungsber. 1886. Vol. XCII, Pt. III, p. 561.

Petrowsky, Zur Frage iiber das Wachstum der Muskelfasern des Muskelgewebes beim
Frosch. Med. Centralbl. No. 49, pp. 769-772.

Pohl-Pincus, Ueber die Muskelfasern des Froschherzens. Arch. f. mik. Anat. 1884,
Vol. XXII, p. 500 ; and Verhandl. der Physiol. Gesell. zu Berlin. 1882-3. No.9.

Ranvier, L., Appareils nerveux terminaux des muscles de la vie organique; cceurs
sanguins, cours lymphatiques; esophagus; muscles lisses. Legons recueillies
par Weber et Lataste. Lecons d’ Anatomie générale faites au Collége de France.
Paris, 1880. Vol. VII, p. 350.

Ranvier, L., Lecons sur l’histologie du Systeme nerveux. 1878. Vol. II.

Reichert, K. E., Ueber das Verhalten der Nervenfasern bei dem Verlauf und En-
digung in einem Hautmuskel des Frosches, Rana temporaria. Arch. f. Anat.
u. Physiol. 1851, p. 29.

Retzius, Zur Kenntniss der quergestreiften Muskelfaser. Biologische Unter-
suchungen. 1881, p. I.

Rouget, Note sur la terminaison des nerfs moteurs dans les muscles chez les reptiles,
les oiseaux et les mammiftres. Comptes rendus. 1862. LV, p. 548.

Sachs, C., Die quergestreifte Muskelfaser. Arch. f. Anat. u. Physiol. 1872,
pp. 607-648.

Sachs, C., Die Nerven der Sehnen. Arch. f. Anat. u. Physiol. 1875, p. 402.

Sandmann, D. G., Ueber die Verteilung der motorischen Nervenendapparate in
den quergestreiften Muskeln der Wirbelthiere. Arch. f. Anat. u. Physiol.
1885, p. 240.

Schénn, Anatomische Untersuchungen im Bereich des Muskel- und Nervengewebes.
Jenaische Zeitschr. 1865. Vol. II, pp. 26-60.

Schultze, M., Ueber Muskelkérperchen und das was man eine Zelle zu nennen habe.
Arch. f. Anat. u. Physiol. 1816, p. 17.

Sokolow, A. A., Sur les transformations der terminaisons des nerfs dans les muscles
de la grenouille aprés les section des nerfs. Arch. de Physiol. normale et patho-
logique, 1874, pp. 300-315.

Sokolow, A. A., Ueber die Nervenendigungen in den Muskeln ausgehungerter
Froésche. Medicin. Bote. 1876, St. Petersburg.

Tergast, P., Ueber das Verhialtniss yon Nerve und Muskel. Arch. f. mik, Anat.
1873. Vol. IX, p. 36.

v. Thanhoffer, L., Beitrage zur Histologie und Nervenendigung der quergestreiften
Muskelfasern. Arch. f. mik. Anat, 1882. Vol. XXI, p. 26.

Thin, G., On the structure of muscular fibre. Quart. Journ. Microsc. Sci. 1877,
Vol. XVI, pp. 251-259.

Tolotschinoff, Ueber das Verhalten der Nerven zu den glatten Muskelfasern der
Froschharnblase. Arch. f. mik. Anat. 1869. Vol. V, p. 510.

Trinchese, S., Mémoire sur la terminaison périphérique des nerfs moteurs dans la
série animale. Journ. de l’Anat. et de la Physiol. 1867, pp. 485-504 (original
in Italian, 1867).

Tschiriew, S., Sur les terminaisons nerveuses dans les muscles striés. Arch. de
physiol. norm. et path. 1879. Vol. VI, p. 89.

Tschiriew, S., Sur les terminaisons nerveuses dans les muscles striés. Compt. rend.
1878. Vol. LXXXVII, p. 604.

Unger, Untersuchungen iiber die quergestreiften Muskelfasern des lebenden Thieres.
Wiener med. Jahrb. 1879, p. 61; and in Centralbl. f. d. med. Wiss. 1879,
No. 34, p- 622.

Wagener, G. R., Ueber die Verbindung von Muskel und Sehne unter einander-
Sitzungsber. naturw. Gesells. Marburg. 1874, pp. 38-46.

430 MUSCLE, CARTILAGE, BONE, AND CONNECTIVE TISSUES.

Waldeyer, W., Ueber die Endigung der motorischen Nerven in den quergestreiften
Muskeln. Centralbl. f. d. med. Wiss. 1863, p. 369.

Waldeyer, W., Untersuchungen tiber den Ursprung und den Verlauf des Axen-
cylinders bei Wirbellosen und Wirbelthieren, sowie iiber dessen Endverhalten
in der quergestreiften Muskelfaser. Henle and Pfeuffer’s Zeitschr. 1864. Vol.
XX, pp. 193-257.

Weismann, A., Ueber die Musculatur des Herzens beim Menschen und in der
Thierreihe. Arch. f, Anat. u. Physiol. 1861, p. 41.

Wolff, W., Ueber den Zusammenhang des Muskels mit der Sehne. Diss. Berlin,
1877; Abstract in Centralbl. f. d. med. Wiss. 1877, p. 733-

Consult also: Arnold, J., Kihne, W., and Schweigger-Seidel, F., in Stricker’s
Handbuch der Gewebelehre.

II. CARTILAGE AND BONE.

Arnold, J., Ueber die Abscheidung des indigschwefelsauren Natrons im Knochen-
zehaclic, Virchow’s Arch. 1877. Vol. LXXI, p. 17.

Arnold, J., Die Ausscheidung des indigschwefelsauren Narions im Knorpelgewebe.
Virchow's Arch. 1878. Vol. LXXTIII, p. 125.

Bigelow, W. 8., Notiz tiber den Theilungsvorgang bei Knorpelzellen sowie iiber —
den Bau des Hyalinknorpels. Arch. f. mik. Anat. 1879. Vol. XVI, p. 457.

Boll, F., Untersuchungen tiber den Bau und die Entwicklung der Gewebe. Arch.
f. mik. Anat. 1871. Vol. VII, p. 275.

Bruch, C., Ueber die Verknécherung der Wirbelsiule bei den Batrachiern. Wiirzb.
naturw. Zeitschr. 1862. Vol. III, pp. 225-238.
Bush, F., Das Knochengewebe der Batrachier nach den Untersuchungen von N.
Kastschenko. Verhandl. d. physiol. Gesells. zu Berlin. 1881, pp. 358-361.
Flesch, Untersuchungen tiber die Grundsubstance des Hyalinknorpels. Wiirzburg,
1880.

Heidenhain, Zur Kenntniss des hyalinen Knorpels. Studien aus d. physiol. Inst.
zu Breslau. 1863. Pt. II, p.4. AS

Hertwig, O., Anatomisch histologische Untersuchung des Skelets der Mundhéhle und
der Zihne der Amphibien ; supplement to Vol. XI. Arch. f. mikroskopische
Anat. 1874, pp. 29-32.

Kastschenko, N., Ueber die Genese und Architectur der Batrachierknochen. Arch.
f. mik. Anat. 1881. Vol. XIX, pp. 1-52.

Kastschenko, N., Ueber die Krappfiirbung der Froschgewebe. Arch. f. mik. Anat.
1882. Vol. XXI, p. 357.

v. Kélliker, Gewebelehre Leipzig. 1867, p. 66.

Lehmann, J. C., Ueber den Knorpel in der Achillessehne des Frosches. Zeitschr.
f. wiss. Zool. 1864. Vol. XIV, p. 109.

Levschin, L., Ueber die Entwicklung des Knochengewebes des Frosches. Centralbl.
f. med. Wiss. Nos. 18, 19.

Mays,-C., Ueber den Bau der Sehnen, etc. Virchow’s Arch. 1879. Vol. LXXV,
p- 112.

Renaud, M. J., Systtme hyalin de sout?nement des centres nerveux et de quelques
organes des sens. Arch. de Physiol. 1881, p. 6.

Schleicher, W., Die Knorpelzelltheilung: Arch. f. mik. Anat. 1879. Vol. XVI,

. 248.

pid, e Ueber die Saftbahnen des hyalinen Knorpels. Wiener Sitzungsber.
1879. Vol. LXXX, Pt. III, p. 267.

Stadelmann, E., Die Histologie des ‘ Pseudoknorpels’ in der Achillessehne des
Frosches, ete. Virchow’s Arch. 1880, Vol. LXXX, p. 105; also as Dissert.
inaug. Kénigsberg, 1878.

LITERATURE. 431

van Stricht, O., Recherches sur le cartilage hyalin. Annales de la soci¢té de médi-
cine de Grand. 1885, pp. 221-232.

Thin, G., On the structure of hyaline cartilage. Quart. Journ. Micros. Sci. 1876.
Vol. XVI, pp- I-22.

v. Térdk, A., Der feinere Ban des Knorpels des Achillessehne aan Frosches. Cen-
tralbl. f. aed: Wiss. 1872, No. 5,p. 66; and Verhandl. d. phys.-med. Gesells. zu
Wiirzburg, 1872, Vol. III, pp. 1-26.

Ill. THE CONNECTIVE TISSUES.

Billroth, T., Ueber die Epithelzellen der Froschzunge, den Bau des Cylinder- und
Flimmerepithel und ihr Verhialtniss zum Bindegewebe. Arch. f. Anat. u.
Physiol. 1858, p. 159.

Bizzozero, G., Ueber den Bau des Sehnengewebes. Moleschott’s Untersuchungen.
1876. Vol. XI, p. 36.

Bobinzky, C., Zur Kenntniss des Baues, der Entwicklung und der regressiven
Metamorphose der Fetzellen. Centralbl. f. d. med. Wiss. 1885. No. 43,
PP- 753-755-

Boll, F., Untersuchungen iiber den Bau und die Entwicklung der Gewebe. Arch.
f. mik. Anat. 1871. Vol. VII, p. 276.

~ Ciaccio, G. V., Nuove Ricerche sull’ interna tessitura dei tendi. Memorie dell’
Academie delle scienze dell Istituto di Bologna, 1872. Series III, Vol. LI.
Abstract in Centralbl. f. d. med. Wiss. 1873.

Czumak, J., Notiz iiber elastische Sehnen. Centralbl. f. med. Wiss. 1863, p.. 785.

Flemming, W., Ueber Bildung und Riickbildung der Fettzelle im Bindegewebe ;

- und Bemerkungen iiber die Structur des letztern. Arch. f. mik. Anat. 1871.
Vol. VII, p. 32.

Gerlach, J., Ueber Bindegewebe. Sitzungsb. d. phys.-med. Societaét zu Erlangen.
1872, p. 78.

Ginsburg, L., Ueber das Verhalten der Sehnenzellen bei der Entziindung. Vir-
chow’s Arch. 1882. Vol. LX XXVIII, p. 263.

Golgi, C., Sui Nervi dei Tendini dell’ Uomo e di altri Vertebrati e di un nuovo
Organo nervoso terminale Musculo-tendineo. Estr. dalle Memorie della Rezle
Ace. diTorino. 1880. Series II, Vol. XXXII, p. 29; No. 6, p. 86.

Hensen, V., Ueber die Entwicklung des Gewebes und der Nerven im Schwanze der
Froschlarve. Virchow’s Arch. 1864. Vol. XXXT, p. 51.

Hoyer, Ueber den Bau der Cylinder- und Flimmerepithelien und ihr Verhiltniss
zum Bindegewebe. Arch. f. Anat. u. Physiol. 1838, p. 163; also Deutsche
Klinik. 1857, No. 21.

Iwanoff, A., Beitrage zur normalen und pathologischen Anatomie des Frosch-Glas-
kérpers. Centralbl. f. d. med. Wiss. 1868, p. 129.

Kollmann, Ueber den Bau der Sehne. Miinchener Sitzungsber. 1878. Abstract in
Centralbl. f. d. med. Wiss. 1879, p. 881.

Maddox, On the apparent relation of nerve to connective-tissue corpuscles. Proc.
Roy. Soc. Lond. 1868. Vol. XVI, p. 61.

Mays, C., Ueber den Bau der Sehnen mit besondere Beriicksichtigung iiber Saft-
bahnen. Virchow’s Arch. 187g. Vol. LXXV, p. 112.

Sachs, C., Die Nerven der Sehnen. Arch. f. Anat. u. Physiol. 1875, p. 402.

Spina, A., Untersuchungen des lebenden Bindegewebes. Ocesterr. med. Jahrb.
1884. Pt. IL.

NOTE BY THE TRANSLATOR.

REFERENCE has already been made to the views of Messrs. Melland
and Marshall on the structure of muscle-fibres. The opinion that
the striation of voluntary muscle is wholly or in part due to the
presence of a regularly arranged network was previously published
by Retzius, Bremer, and others. The authors referred to have
now for the first time shown the importance of this network in
all vertebrate muscular tissues, whether voluntary or involuntary.

Mr. Marshall gives the following summary of the result of his
researches, which the Translator has confirmed by his own obser-
vations :—

1. In all muscles which have to perform rapid and frequent move-
ments, a certain portion of the muscle is differentiated to perform
the function of contraction, and this portion takes on the form of
a very regular and highly modified intracellular network.

2. This network, by its regular arrangement, gives rise to certain
optical effects which cause the peculiar appearances of striped
muscle.

3. The contraction of the striped muscle-fibre is probably caused
by the active contraction of the longitudinal fibrils of the intracellular
network ; the transverse networks appear to be passively elastic, and
by their elastic rebound cause the muscle to rapidly resume its
relaxed condition when the longitudinal fibrils have ceased to
contract ; they are possibly also paths for the nervous impulse.

4. In some cases where muscle has been hitherto described as
striped, but gives no appearance of the network on treatment with
the gold and other methods, the apparent striation is due to optical
effects caused by a corrugated outline in the fibre.

5. In muscles which do not perform rapid movements, but whose
contraction is comparatively slow and peristaltic in nature, this
peculiar network is not developed. In most if not all of the

NOTE BY THE TRANSLATOR. 433

unstriped muscles of invertebrates there does not appear to be an
intracellular network present in any form, but im the unstriped
muscle of vertebrates there are longitudinal fibres only; these
possibly represent a form of network intermediate between the
typical irregular intracellular network of other cells and the highly
modified network of striped muscle.

6. The cardiac muscle-cells contain a Anetxvork similar to that of
ordinary striped muscle.

rf

DESCRIPTION OF THE FIGURES ON PLATE II.

Fig. 180 (p. 278).
I. Preparation of the mucous membrane of the dorsal surface of the mouth and oesophagus to show
the vascular supply. Arteries red, veins blue ; after Sch6bl.
II. Small portion of the above to show the dilatations on the capillaries ; after Schdbl.

Fig. 187 (p. 285).

Transverse section through the mucous membrane of the fundus of the stomach of Rana esculenta.
Alcohol preparation, doubly stained with carmine and anilin blue. After Biedermann.
(Oc. II, Syst. 7, Hartnack.)

Fig. 196 (p. 298).
I. Partial injection of the liver from the portal vein (blue): Rana esculenta.—G. H.
II. Partial injection of the liver from the hepatic vein (red): Rana esculenta,—G. H.

III. Complete injection of the liver from the hepatic artery (red) and from the portal vein (blue) :
Rana esculenta.—G. H.

A Portal (interlobular) veins and their branches.

B Hepatic (intralobular) veins and their branches.

C Hepatic arteries and their branches.

Fig. 208 (p. 318).
Two sections from the lung of Rana temporaria ; stained with borax-carmine.—G. H.
I. The lung dilated (Hartnack, Oc. I, Syst. 3).
II. The lung contracted (Hartnack, Oc. I, Syst. 7).

A Band of muscle cut transversely.
B Band of muscle cut longitudinally.
C Muscular layer of surface,

Fig. 217 (p. 334).
Portions of two transverse vertical sections through the kidney.—G. H.

I. Kidney of Rana esculenta, partial injection of the uriniferous tubes with silver nitrate (Hartnack,
Oc. I, Syst. 7). :

II, Kidney of Rana temporaria, stained with borax-carmine (Hartnack, Oc. I, Syst. 7).

Fig. 219 (p. 337)
Two portions from a gold preparation of the kidney of Rana esculenta.—G. H,

I, Showing the tendency to split into lobules,
II, Nerve-fibres accompanying the blood vessels.
a Blood-vessels, b Nerves,

APPENDIX.

I. WORKS WHICH DESCRIBE ORGANS OR SETS OF
ORGANS IN THE FROG.

Bettade, E., Sulle diverse forme delle R. temp. in Europa e pit particolammente
nell’ Italia. Venezia, 1885.

Brehm, A. C., Illustriertes Thierleben. Hildburghausen, 1869. Vol. V.

Burdon-Sanderson, Handbook for the Physiological Laboratory. London, 1873.

Camerana, L., Recherches sur les variations de la R. esculenta et du Bufo viridis
dans le bassin de la Méditerranée. Paris, 1883.

Carus, C. G., Lehrbuch der vergleichenden Zootomie. 2nd Edit. Leipzig, 1834.

Cepéde, Comte de la, Histoire naturelle des quadrupédes ovipaires et des serpens.
Paris, 1808.

Dugés, Recherches anatomiques et physiologiques sur les Reptiles. Ext. des An-
nales des Sciences naturelles. Paris, 1827.

Duméril and Bibron, Erpétologie générale ou histoire compltte des Reptiles.
1836.

Ecker, A., Icones physiologicae. Leipzig, 1851-1859.

Fatio, V., Faune des vertébrés de ]a Suisse. Gentve et Bale, 1872.

Gegenbaur, C., Grundziige der vergl. Anatomie. Leipzig, 1870.

Gegenbaur, C., Grundriss der vergl. Anatomie. Leipzig, 1878.

Gerlach, Handbuch der Histologie. 1853-1854.

Gesner, C., Historia Animalium. LiberI. 1551.

Gesner, C., Icones Animalium. 1560.

v. Griesheim, A., Ueber die Zahlenverhaltnisse der Geschlechter bei R. fusca.
Pfliiger’s Arch. f. d. ges. Physiol. 1881. Vol. XXVI, p. 3.

Hoffmann, C. K., Bronn’s Klassen und Ordnungen des Thierreichs. Vol. VI, Am-
phibien. Leipzig, 1873-1878.

Howes, G. B., An Atlas of Practical Elementary Biology. London, 1885.

Huxley, T., Anatomy of the Vertebrated Animals. London, 1871.

Huxley, T., Lectures on the Elements of Comparative Anatomy.

Huxley, T., Article Amphibia, Encyclopaedia Britannica. IXth Edit. 1875.

Klein, E., Beitrage zur Anatomie der ungeschwanzten Batrachier. Jahreshefte.
Wirttemberg, 1850, pp. 1-84.

Klein, E., and Noble Smith, Atlas of Histology. London, 1879-1880.

Kloezke, C. G., Dissertatio anatomica de Rana cornuta. Berolini, 1816.

v. Kélliker, A., Handbuch der Gewebelehre. 5th Edit. Leipzig, 1867.

Kuhl, H., Beitrage zur Zoologie der Rana esculenta: in Beitr. z. Zool. Frankfurt
a. M., 1820.

Laurenti, J. N., Synopsis Reptilium. Viennae, 1768.

Leydig, F., Lehrbuch der Histologie. Frankfurt a. M., 1857.

Marshall, A. M., The Frog. 3rd Edit. London and Manchester, 1888.

Mayer, A. F., Beitrage zu einer anatomischen Monographie der Rana pipa. Acad.
Caes. Leop. Nov. Acta, 1825. Vol. XII, p. 527.

Ff2

436 APPENDIX.

Meckel, J., Beitriige zur vergleichenden Anatomie. Leipzig, 1811.

Meckel, J., System der vergleichenden Anatomie. Halle, 1833.

Mivart, St. Geo., On the Classification of the Anurous Batrachians. Proc. Zool. Soc.
1869.

Mivart, St. Geo., The Common Frog. London, 1874.

Miller, J., Beitriyge zur Anatomie und Naturgeschichte der Amphibien. Tiede-
mann’s Zeitschr. 1831, p. 190.

Miller, J., The Physiology of the Senses, etc. Translated by W. Baly. London,
1848.

Owen, R., Anatomy of the Vertebrates. London, 1866.

Ranvier, L., Lecons d’anatomie générale. Paris, 1880.

Résel v. Rosenhof, Historia naturalis ranarum nostratium. Niirnberg, 1758.

Rudolphi and Breyer, Observationes anatomicae circa abricam Ranae_ pipae.
Berolini, 1811.

Rusconi, M., Développement de la grenouille commune. Milan, 1826.

Schneider, J. G., Historia amphibiorum. Jenae, 1799.

Schwalbe, G., Lehrbuch der Anatomie der Sinnesorgane. Erlangen, 1885.

Stannius, H., Zootomie der Amphibien (Handb. der Zoot. der Wirbelthiere, 2 Buch).
and Edit. Berlin, 1856.

Stricker, S., Beitrige zur Biologie der Batrachier. Wien. ‘Zool. Bot. Verhandl.
1866. Vol. XVI, pp. 451-456.

Stricker, 8., Handbuch der Gewebelehre.

Stricker, 8., Manual of Human and Comparative Histology. Translated by
H. Power. London, 1870.

Swammerdam, J., Biblia Naturae Amstelodamensis. (Dutch and Latin by
Gaubius. Leidae, 1738.)

Todd and Bowman, The Physiological Anatomy and Physiology of Man. London,
1845-1857.

Vogt, C., Zoologische Briefe. Frankfurt a. M., 1851. :

Wagler, J., Natiirliches System der Amphibien. Miinchen, Stuttgart, and Tt-
bingen, 1830,

Wagner, R., Lehrbuch der vergleichenden Anatomie. Leipzig, 1834-1835.

Wagner, R., Icones Zootomicae. Leipzig, 1841.

Wagner, R., Handworterbuch der Physiologie. 1842.

Waters, W. H., Histological Notes. Manchester and London, 1884.

Wiedersheim, R., Lehrbuch der vergleichenden Anatomie der Wirbelthiere. 2nd
Edit. Jena, 1886.

Wiedersheim, R., Elements of Comparative Anatomy of Vertebrates. Translated
by N. Newton Parker. London, 1886,

Il. WORKS RELATING TO THE EMBRYOLOGY AND
DEVELOPMENT OF THE. FROG,
Balfour, F. M., Treatise on Comparative Embryology. London, 1880.

Born, G., Beitriige zur Bastardirung zwischen den einheimischen Anurenarten.
Pfliiger’s Arch. f. d. ges. Physiol. 1883. Vol. XX XIT, p. 453.

APPENDIX. 437

Durham, H. E., Note on the presence of a Neurenteric Canal in Rana. Quart.
Journ. Micros. Sci. 1886. Vol. XXVI, p. 509.

Giles, A. E., The development of the fat-bodiesin Rana temporaria. Quart. Journ.
Micros. Sci. 1888. Vol. X XIX.

Goette, A., Kurze Mittheilungen aus der Entwicklungsgeschichte der Unke. Arch.
f. mik. Anat. 1873. Vol. IX, p. 396.

Goette, A., Entwicklungsgeschichte der Unke. _ Leipzig, 1875.

Hertwig, O., Die Entwicklung des mittleren Keimblattes der Wirbelthiere. Jena,
1883.

Johnson, A., and Sheldon, L., Notes on the Development of the Newt (Triton
cristatus). Quart. Journ. Micros. Sci. 1886. Vol. XXVI, p. 573-

Marshall, A. M., The Frog: An Introduction to Anatomy, Histology, and Embryo-
logy. 3rd Edition. Manchester and London, 1888.

Pfliger, E., Einige Beobachtungen zur Frage iiber die das Geschlecht bestimmenden
Ursachen. Pfitiger’s Arch. f. d. ges. Physiol. 1881. Vol. XX VI.

Pfliger, E., Hat die Concentration des Samens einen Einfluss auf das Geschlecht ?
Pfliiger’s Arch. f. d. ges. Physiol. 1883. Vol. X XIX, p. 1.
Pfliger, E., Zusammenstellung der Ergebnisse und Erérterung der Principien der
Zeugung. Pfliiger’s Arch. f. d. ges. Physiol. 1883. Vol. XXXII, p. 542.
Pfliger, E., and Smith, W. J., Experimente iiber Bastardirung der anuren Batra-
chier. Pfliiger’s Arch. f. d. ges. Physiol. 1883. Vol. XXXII, p. 519.

Remak, Untersuchungen iiber die Entwickelung der Wirbelthiere. Berlin, 1855.

Schultze, O., Zur ersten Entwickelung des braunen Grasfrosches. Leipzig, 1887.

Schultze, O., Die Entwicklung der Keimblitter und der Chorda dorsalis von Rana
fusca. Zeitschr. f. wiss. Zool. 1888. Vol. XLVI, p. 325.

Spencer, W. B., Some Notes on the Early Development of Rana temporaria.
Quart. Journ. Micros. Sci. 1885. (Supplement.)

Stricker, S., Untersuchungen iiber die Entwicklung des Kopfes der Batrachier.
Arch. f, Anat. u. Physiol. 1864, p. 52.

Térok, A., Beitrage zur Kenntniss der ersten Anlagen der Sinnesorgane und der
primiren Schiidelformation bei den Batrachiern. Moleschott’s Untersu-
chungen, 1870. Vol. X, p. 338.

Ill. ADDITIONS TO THE LISTS GIVEN AT THE
HEADS OF THE SECTIONS.

1. THe Bones.

Albrecht, P., Note sur le basi-occipital des batraciens anoures. Extr. d. Bullet. d.
Musée royal d’hist. nat. de Belgique. 1883. Vol. IT.

Born, G., Die sechste Zehe der Anuren. Morphol. Jahrb. 1876. Vol. I.

Born, G., Ueber das Skelet des Fersenhéckers von Rana fusca, ete. Sitzungsb. d.
Schles. Gesell. f. vaterlind. Cultur. 1879.

Born, G., Nachtriige zu Carpus und Tarsus. Morph. Jahrb, 1880, Vol. VI.

Ecker, A., Icones physiologicae. Leipzig, 1881-1889.

438 APPENDIX.

Ecker, A., Die Anatomie des Frosches. 2nd Edition. Braunschweig, 1888,
pp- 17-62.

Gegenbaur, Untersuchungen zur vergl. Anatomie der Wirbelsiiule bei Reptilien
und Amphibien. Leipzig, 1862.

Gegenbaur, Grundziige der vergl. Anatomie. Leipzig, 1870.

Goette, A., Brustbein und Schultergiirtel auf entwickelungsgeschichtlicher Grund-
lage verglichen bei Amphibien und Anurioten. Arch. f. mik. Anat. 1877.
Vol. XIV, p. 502.

Howes, G. B., On some abnormalities of the Frog’s vertebral column. Anat. Anz.
1886. Vol. I, Pt. II.

Leydig, F., Ueber den Bau der Zehen bei Batrachiern und die Bedeutung des Fer-
senhéckers. Morphol. Jahrb. 1876. Vol. II.

Parker, W. K., A monograph on the structure and development of the shoulder-
girdle and sternum. Ray. Soc. 1867.

Schneider, J. G., Historia amphibiorum. Jenae, 1799.

Stohr, P., Zur Entwickelungsgeschichte des Anurenschidels. Zeitschr. f. wiss.
Zool. 1881. Vol. XXXVI.

Torok, A., Beitrige zur Kenntniss der ersten Anlagen der Sinnesorgane und der
primaren Schidelformation bei den Batrachiern. Moleschott’s Untersuchungen.
1870. Vol. X, p. 338.

2. Tue Musctres.

Albrecht, P., Beitrag zur Morphologie des M. omohyoides und der ventralen inneren
Interbranchial-Musculatur. Inaug. Dissert. Kiel, 1876.
Ecker, A., Die Anatomie des Frosches. 2nd Edition. Braunschweig, 1888,
pp- 65-139.
Hoffmann, C. K., Bronn’s Klassen und Ordnungen des Thierreichs. Vol. VI.
~Amphibien. Leipzig, 1873-1878.
Howes, G. B., An Atlas of Practical Elementary Biology. London, 1885.

3. NeErvous System.

Engelmann, T. W., Ueber die Discontinuitat des Axencylinders und den fibrilliren
Bau der Nervenfasern, Pfliiger’s Arch. f. d. ges. Physiol. 1880. Vol. XXII,
p. I.

Grandry, Recherches sur la structure interne du cylindre de l’axe et des cellules ner-
veuses. Bull. de Acad. Roy. du Belgique. 1868.

Hodge, C. F., Some effects of stimulating ganglion-cells. (Some anatomical details
regarding the relations of nerve-fibres with nerve-cells are given.) American
Journ. of Phys. 1888.

Owsjannikow, P., Ueber die Rinde des Grosshirns. Mémoires de l’acad. impé-
riale des sciences de St. Pétersbourg. 1879. Series VII, Vol. XX VI, No. 11.

Spiro, Physiologisch-topographische Untersuchungen am Riickenmark des Frosches.
Mémoires de l’acad. impériale des sciences de St. Pétersbourg. 1870. Series VII,
Vol. XVI, No. 7.

Waldeyer, W., Untersuchungen iiber den Ursprung und Verlauf des Axencylinders.
Henle u. Pfeuffer’s Zeitschr. 1864. Vol. XX, pp. 193-257.

Consult also: Gerlach, J., Mayer, S., and Schultze, M., in Stricker’s Handbuch
der Gewebelehre.

APPENDIX. 439

4. THe VAscuLarR SYSTEM.

Barthol, P., Sopra il sistema linfatico dei Rettili. Pavia, 1833.

Blaschek, A., Untersuchungen iiber Herz, Pericard, Endocard, und Pericardhohle.
Schenk’s Mitt. 1885. New Series, p. 32.

Eberth, C. J., in Stricker’s Handbuch der Gewebelehre.

Klein, E., On the peripheral distribution of non-medullated nerve-fibres (nerves of
the blood-vessels in the frog’s tongue). Quart. Journ. Micros. Sci. 1872.
Vol. XII, p. 123.

Mayer, S., Studien zur Histologie und Physiologie des Blutgefasssystems. Wiener
Sitzungsb. 1886. Vol. XCIII, Pt. ITI, p. 45.

v. Recklinghausen, F., (The lymphatics) in Stricker’s Handbuch der Gewebelehre.

Rollett, A., (The Blood) in Stricker’s Handbuch der Gewebelehre.

Teichmann, L., Untersuchungen iiber das Saugadersystem. Leipzig, 1861.

5. THE ALIMENTARY CANAL.

Heidenhain, R., Beitrage zur Kenntniss des Pancreas. Pfliiger’s Arch. f. d. ges.
Physiol. 1875. Vol. X, p. 557.

Krause, W., Anatomische Untersuchungen (Tongue). Hannover, 1861.

Consult also: Klein, E., The Oral Cavity and the Oesophagus; Miller, W., The
Spleen; Eberth, C. J., The Liver, in Stricker’s Handbuch der Gewebelehre.

6. THe Lunes anp Larynx.

Holmgren, F., Methode zur Beobachtung des Kreislaufs in der Froschlunge. Beitr.
z. Anat. u. Physiol. Festgabe f. C. Ludwig. Leipzig, 1874.

Meckel, J. F., Beitriige zur Geschichte des Respirations-Systemes der Amphibien.
Meckel’s Arch. 1849. Vol. V.

Schmidt, C., De l’épithelium pulmonaire. 1866.

Williams, Article Respiration, in Todd’s Cyclopaedia of Anat. and Physiol. 1859.
Vol. V.

7. Toe Urrno-Genitat System, THE ADRENALS, AND
THE Fat-Bopteés.

Aeby, C., Ueber glatte Muskelfasern im Ovarium und Mesovarium von Wirbel-
thieren. Arch. f. Anat. u. Physiol. 1859, p. 675.

Giles, A. E., The development of the fat-bodies in Rana temporaria. Quart. Journ.
Micros. Sci. 1888. Vol. XXIX.

. Grohe, F., Ueber die Bewegung der Samenkérper. Virchow’s Arch. 1865.
Vol. XXXII, p. 416.

Virchow, R., Ueber die Dotterplittchen bei den Fischen und Amphibien. Zeitschr.
f. wiss. Zool. 1849. Vol. IV.

Consult also: Eberth, C. J.; v. La Valette St. George; Ludwig, C.; Grin-
wald; Obersteiner, H.; and Stricker, S., in Stricker’s Handbuch der Ge-
webelehre.

440 APPENDIX.

8. THe SKIN AND SENSE-ORGANS.

a. The Skin.

Busch, A., Phiinomene aus dem Leben der Pigmentzellen. Arch. f. Anat. u.
Physiol. 1856, p. 415.

b. Special Organs of Tactile Sensation.

Mitrophanow, P., Zur Entwicklungsgeschichte und Innervation der N ervenhiigel
der Urodelenlarven. Biologisches Centralb. 1887, p. 174.

ce. The. Organs of Taste.

Beale, L. 8., New Observations upon the Minute Anatomy of the Papillae of the
Frog’s Tongue. Phil. Trans. 1865. Vol. CLV, p. 443.

Engelmann, T. W., in Stricker’s Handbuch der Gewebelehre.

Maddox, R. L., A Contribution to the Minute Anatomy of the Fungiform Papillae
and terminal arrangement of Nerve to striped Muscular Tissue in the Tongue of
the common Frog. Monthly Micros. Journ. 1869, p. I.

d. The Ear.

Albrecht, P., Sur la valeur morphologique de la trompe d’Eustache. Communica-
tion faite & la Société d’ Anatomie Pathologique de Bruxelles. 1884.

v. Kélliker, Handbuch der Gewebelehre. 5th Edit. Leipzig, 1867.

Leydig, F., Handbuch der Histologie. Frankfurt a. M., 1857.

Riidinger, in Stricker’s Handbuch der Gewebelehre.

e. The Nose.

Marshall, A. M., Morphology of the Vertebrate Olfactory Organ. Quart. Journ.
Micros, Sci. 1879. Vol. XIX, p. 330.

f. The Eye.

Ciaccio, G. V., Beobachtungen iiber den inneren Bau des Glaskérpers im Auge des
Menschen und der Wirbelthiere im Allgemeinen. Moleschott’s Untersu-
chungen, 1870. Vol. X, p. 383.

Hannover and Finkbeiner, Vergleichende Untersuchungen der Stiirke des Glas-
kérpers bei den Wirbelthieren. Zeitschr. f. wiss. Zool. 1855. Vol. VI, p. 335.

Hirschberg, J., Zur Dioptric und Ophthalmologie der Fish- und Amphibienaugen.
Arch. f. Anat. u. Physiol. 1887, p. 493.

Ranvier, L., Le mécanisme de la Séerétion. Lecons faites au Collége de France
en 1886-1887. (Nictitating membrane.) :

Consult also: Rollett and Stieda, in Stricker’s Handbuch der Gewebelehre.

INDEX.

—+4+—

32 33
comm. ant., 163.
coraco-clavicularis, 231.
costo-cervicalis, 231.
cruris inf., 239.
cut. calcanei, 239.

. cut. fem. med., 237.

post., 237.
pectoris, 231.

haemorrhoid. inf., 236.

lobi hemisph. inf. ext., 163.
” zs sup. int., 163.
32 optici, 163.

malleol. lat., 240.

malleol. med., 240.

pharyngo-maxill., 230.

ramus auricularis, 228, 230.

2 2?

‘a maxillaris comm., 228.

inf., 230.
- e sup., 228.
» orbito-nasalis, 228.
scapularis post., 232.
sup., 232.

spinalis ant., 163.

22 2?

Abducens nerve, p. 171. Arteria subscapularis, 232.
a nucleus, 146. 3 8suralis, 239.
Acetabulum, 48. Arteries, 222.

. Acromial, 39. oe of brain, 162.
Adrenals, 348. zs of choroid, 411.
Ala magna, 25. ~ of foot, 240.

» temporalis, 25 + of hyaloid, 421.
Alar cartilages, 28. + of iris, 413.
Alimentary canal, 258. = of skin, 376.

’ Ampulla anterior, 396. =! of vitreous body, 421

+ external, 3 Artery, ant. palatine, 224.

” posterior, 398 i 2 2 tibial, 239-
Angulo-splenial, 34. ” |» 232.
Ankle, 50. ; » carotid, 224.
Anterior es 396. + Ciliary, 226.

» brachial lymph-sac, 259. } :: coeliaco-mesenteric, 233-

- brachio-radial septum, 258. :> femoral, 236.

» brachio-ulnar septum, 258. » gastric, 233. -

chamber, 409. :> haemorrhoidal, 235.
Aorta dorsal, 233. » hepatic, 298.
Aponeurosis plantaris, 105. » hyaloid, 226.
Arachnoid, 162. » iliac, 235.
Arteria basillaris, 163. BS internal carotid, 225.

> bulbi, 222. > laryngeal, 226.

» circumflexa genu. lat. sup., 238. »x lingual, 224.

” ” 2 » inf, 238. 7 lumbar, 235-

- Be » Med. sup., 238. +» mesenteric, 234.

¥ » inf, 238. +; occipital, 228.

occipito-vertebral, 226.
; 226.
ophthalmic, 225, 411, 413

ulnar, 233.
urino-genital, 235.
vertebral, 226..
vesico-epigastric, 235.

Articular processes, 17.
Articulations of vertebrae, 19-

of atlas, 24.

Auditory nerve, 172.

442

Auditory nucleus, 144.
Auerbach’s plexus, 292.
Auricles, 214.

Auriculo-ventricular valves, 216.

Axillary septum, 258.
Axis-cylinder, 202.

Bidder’s ganglion, 220.
Bile-ducts, 298.
Bladder, gall-, 295, 299.
5 urinary, 338.
Blood, 262.
Bones and joints, 13.
Bowman’s glands, 387.
Brachial nerve, 183.
Brachio-ulnar lymph-sac, 259.
» radial 3 259.
Brain, 141.

Calcaneum, 50.
Calcified cartilage, 15.
Canales coccygei, 21.
Canalis vertebralis, 20.

» Yami ant. acustici, 393.
Capitulum radii, 43.
Capsule of labyrinth, 391.

» of lens, 413.
Carotid arch, 222.

gland, 225,
Cartilage, calcified, 15.

= of shoulder-girdle, 4o.

Py of skull, 29.
Cartilages of larynx, 312.

- of nose, 27, 385.
Cauda equina, 135, 189.
Cava recto-vesicalis, 304.
Cavitas sigmoidea maj., 43.

Central canal of cord, 137.

» group of cells, 139.
Cerebellum, 148.

Cerebral hemispheres, 156.
Chamber, anterior, 409.

; posterior, 420.
Chiasma, optic, 153, 155, 167.
Chorda dorsalis, 20.

Chordae tendineae, 216.
Choroid coat, 409.

» plexus of fourth vent., 142, 164.
153, 164.

» _ third _,,
Ciliary nerves, 169.

» processes, 420.
Cireulus iridis major, 413.
Clavicle, 39.

Cloaca, 347.
Columella auris, 25, 390.
Commissura anterior, 159.
x. inferior, 140.
es posterior, 159.
FE superior, 140.
¥. transversa, 154.

INDEX.

Common bile-duct, 296.
Cones, 418.
Conus medullaris, 135.
Coracoid, 39.
Coracoid foramen, 39.
Cornea, 406.
Corpora quadrigemina, 152.
Corpus callosum, 158, 159.

» Striatum, 158, 159.
Corpuscles of blood, 263.

Ss of Hassall, 321.

Coverings of brain and cord, 162.
Cranial nerves, 141, 167.
Cranium, 23.
Cricoid cartilage, 312.
Crista acustica, 397.

sr deltoidea, 41.

» medialis, 42.
Crusta petrosa, 279.
Cupula terminalis, 398.
Cutaneous glands, 372.
Cuticula dentis, 279.
Cutis, 369.
Cystic duct, 295.

Dentale, 35.
Dentary, 34.
Dentine, 279.
Descemet’s membrane, 407.
Dorsal lymph-sac, 255.
9» roots, 140.
» Septum, 252.
Duct, common bile-, 296.
» eystic, 295.
Ductus choledocus, 296.
», endolymphaticus, 398.
»» fenestra ovalis, 394.
» perilymphaticus, 395.
», Wirsungianus, 301.
Dura mater, 162.

Ear, 389.

Enamel, 279.

Enlargements of cord, 133, 137.
Epicoracoids, 37.

Epidermis, 367.

Epiglottis, 317.

Episternum, 36.

Epithelium of ventricles, etc., 160.
Exoccipitals, 23.

External limiting membrane, 420.
Extrastapedial, 26, 390.

Eye, 405.

Eyelids, 422.

Facial nerve, 171.

Fat-bodies, 348.

Femoral lymph-sae, 260.
Fibrae arcuatae cerebelli, 149.

Fibres of brain, 161.
Filiform papillae, 380.
Filum terminale, 135.
Foramen condyloideum, 24.

> magnum, 23.

Ss Monroi, 157.

55 ovale, 24.

= parietale, 156.

rotundum, 392.
Formatio reticularis, 140.
Fossa condyloidea, 24.
>» _tympamnica, 24.

Fourth ventricle, 142.
Fronto-parietal bones, 26.
Fungiform papillae, 380.

Gall-bladder, 295, 299-
Ganglia of bladder, 340.
of heart, 220.

a Ot spinal, 177-
Ganglion ciliare, 168.

condyloideum, 173.

2

, 280.

», thyroid, 322.
Gl ryngeal nerve, 172
Goblet-cells, 289.

Goll’s columns, 140.
Grey matter, 139.

Hair-cells of ear, 404.

of nose, 388.
Harder’s glands, 424.
Hassall’s corpuscles, 321.
Heart, 213, 214.

» endothelium, 320.
muscle, 216.

>> herves, 219.

+ Structure of, 216.
Hepatic arteries, 421.
portal system, 248.

9. Veins, 297.
Hip-joint, 49.
Humerus, 41.
Hyaloid artery, 421.
membrane, 421.

2?

9

INDEX.

443

Hyoid, 35.
Hypoglossal nerve, 182.

53-
Inferior femoral septum, 259.
» __ sinus, 383.
Infundibulum, 153.
Inguinal septum, 254.
Inner molecular layer, 415.
> nuclear peer iS
Interfemoral lymph-sac, 260.
In glands, 280.
Intermediate fem. septum, 259.
Internal ear, 391.
limiting membrane, 414, 420.
* muscles of eye, 413.
arose 9 25, 391.
Intestine, 286
Intumescentia ant. and post., 135.
Tris, 412.

2

| Ischia, 48.

Kidney, 332.
Knee-joint, 50.

| Labyrinth membranous, 395.

suprachoroidea, 4iI.

Larynx, 311.
Lateral group of cells, 139.

lymph-sac, 255.

>

>»?

Lens, 413.

Lieberkiihn’s glands, 288, 293.
Ligament. calcanei, 19.
coronarium, 303,

3 gastro-duodenale, 305.
zs hepato-duodenale, 287,

co pectinatum iridis, 409.

suspensor. hepatis, 304.
y verteb. comm. ant., 19.
post., 19.

>

Limiting membrane, external, 420.

‘ > internal, 414, 420.
Lips, 275.
Literature on adrenals, 330.

444

Literature on alimentary canal, 268.
in 5» blood, 2rt.

" s, blood-vessels, 205.

* »» bones and joints, 13.
Bs » cartilage, 431.

6 » connective tissues, 432.

>» 1» ear, 356.

33 » embryology, 436-437.
” + eye, 360.

5 3, fat-bodies, 330.

5 », gall-bladder, 272.

” ” general, 43 5~436 ’

s - heart, 205.

“ »> Intestine, 270.
» »» larynx, 309.
xs » liver, 272.

” ” lungs, 309.
5 »» lymph, 211.

» ,»» lymphatic system, 209.
3 »» mouth, 268.

Fae 4 muscle structure, 427.
As >> muscles, 54.
% »» nervous system, 122.
” »» NOSe, 357-
on », pancreas, 272.
+ 5» peritoneum, 274.
‘9 »» respiratory system, 309.
” » Skin, 353.
+ », Spleen, 273.
ms >» taste-organs, 356.

“93 », thymus, 310.
” », thyroid, 310.
” », touch-organs, 356.

” »» urino-genital system, 326.

Liver, 294.
» cells, 298.
» pigment of, 299.
>, vessels of, 297.
Lower eyelid, 422.
» ~ nasal glands, 386.
Lungs, 317.
Lymph, 264.
Lymph-hearts, 261, 264.
Lymph-saes of ant. extremity, 258.

» », of hinder extremity, 259.

an » of trunk, 251, 255, 264.
Lymphatic system, 251.

Macula lutea, 419.
Malpighian bodies of kidney, 334.
a » of spleen, 303.
Mandible, 34.
Maxillary bones, 32.
septum, 253.
Meckel’s cartilage, 35.
Mediostapedial, 25; 390.
Medulla oblongata, 142.
Medullary segments, 202.
is sheath, 201.
Medullated nerves, 201,
Meissner’s plexus, 291.

INDEX.

Membrana choriocapillaris, 411.
% limitans ext., 420.
” » int., 414, 420.
ss nictitans, 58, 422.
FS suprachoroidea, 411.
Membrane of Descemet, 407.
Membranous labyrinth, 395.
Mentomeckelian cartilage, 35.
Mesocephalic ganglion, 168.
Metacarpus, 46.
Metatarsus, 52.
Meynert’s fibres, 155.
Molecular layer, inner, 415.
», outer, 419.
Motor-oculi, 167.
Mouth, 275.
Movements of hand, 46.
Mucous glands of skin, 375.
Miiller’s fibres, 420.
Muscle, histology, 433.
Muscles, 53.

Muscles of abdomen, 67.
9 ? back, 71.
” »» Cloaca, 347.

” x eye, external, 55
»> 99 99 *internal, 413.

9 9 face, 59-
” »» foot, 105.
5 », forearm, 84.

5 », forelimb, 75.
= », hand, 87.
‘ Be) hinder limb, 94.

s - larynx, 315.

Pr », lower jaw, 60.
», skin, II9g.

Muse. abduct. dig. I brev., 114.
” » ” a 29 92.
”? ” 39 22198 long., gi.
” ” ” V, 113.
es ¥ lV Tare 110,
A a 33), ee dOnes) FTO:
” ” ” I ” 86.
” ” sav: prim., gi.
re 5 » Vsecund,, gI.

hallucis, 109.
pollicis, 87.

aa brev., I14.

;» adduct. brev., roo.
dig. I long., 109.
” ” ” IT, 89.

” » ” Vv, 113.
shy longus, 99.

” ” magnus, 99.

ag pollicis, 87.

5 anconaei, 87.

»» antibrachii lat., 85.
med., 85.
” ” prof., 85.

», biceps fem., 96.

ys» coceygeo-cutaneus, 120.
5 » ciliacus, 74.

”? 3?

INDEX.

Muse. coccygeo-sacralis, 73.

2?

compressor cloacae, 348.
constrictor aditus laryngis, 315.
constrictor iridis, 413.
coraco-humeralis, $2.
eucullaris, 71. F
cutaneus dorsi, 119.
pectoris, 119.

dilator aditus laryngis, 315.
deltoidens, 82.
depressor maxill. inf., 60.

cE palpebrae inf, 58.
dilator iridis, 413.

» larium, 59.
extensor brevis, 106.

53 carpi ulnaris, 86.

ceruris brevis, 104.

tn a I brey., 114.

> s long., II4.

” a Il brev., I1I4.

a” ie long., II4.

” +> 3) Prop. brev., 92.
oy ” oo long., 92.
» , III brev.,115.

” 2? ” long., 115.

2 s+ _33 PFOP-; 93-

od > IV, 116.

” ” ” brev., 116.

2 > +> Prop., 93-

»» © brev., 115.

. rere ene

’ >> 3) comm. brev., gI.
3 2 39 » ~ long., 87.

dorsi comm., 73.
flex. antibrach. lat. superf., 85.
” ” med. 85.
” ”? prof., 85.
” brev. digit. I, Too.

” ” ” TV, 112.
”? 3 2? Vv; 113
+ carpi radialis, 84.

3 ” ulnaris, 84.

» digit. comm., 85, 87.
9? ” I, +i, 108,

aN », Il brey., 89.

: ;, I long., 88.

II prop., 110.

29 2? II tert., 89.

oS ” III brev., 89.

> 3 Til long., 89.

; »» III prop., 111.
»» II, TV, V, 107.
” IV "brev., go.
++» long., go.

» 19) 39 DEQRp ae
» VW brey., go.

» oo long., go.

” 9» Prop., T13-

” _metacarp. digit. IIT, go.

» 99.
metatars. digit. Il, To.
ITT, ri.

3”? bb)

445

Muse. flex. metatars. digit. IV, 112:

»» Phal. prop. dig. ITI, rr2.

: » IV, ant., 113.
»» LV, post., 113.

” ” 7 ” a" go.

” 2? ” 113.

» tarsi ant., 104.
3» post., 114.

gastrocnemius, Io2.
genioglossus, 66, 281.

geniohyoideus, 64.

glutaeus, 94.

hyo-arytenoideus anterior, 315.
posterior, 315.

hyoglossus, 66, 281.

ilio-fibularis, 96.

ilio-lumbaris, 74.

ilio-psoas, IOI.

infraspinatus, 79.

intercrurales, 75.

interossei, 93, 113- ’

a dorsales, 116.
interscapularis, 78.
intertransversar. cap. sup., 75.

” b> J ” inf, 75-
” » dorsi, 75.
lateralis narium, 60.

latissimus dorsi, 72.
levator ang. scap., 76.

» bulbi, 57.
longissimus dorsi, 72.
lumbricales, 1ro8.
masseter, 62.
nasalis ext., 60.
obliquus ext., 67

” inf., 56.

be int., 67.

» sup., 56.
obturat., 182.
omohyoideus, 65.
opponens dig. I, Iro.

” 3”?

petrohyoideus ant., 65.
petrohyoidei post., 66, 315.
plantaris, 107.
protrahens scap., 76.
pterygoideus, 61.
pytiformis, 95.
quadratus fem., 112.
rectus abdom., 67.

» extern. bulbi, 55.

+» fem. ant., 95.

33 EferS RS

» inter. ” 55-

” intern. maior, 97-

7 super. ant., 56.

intern. minor, 98.

retractor bulbi, 56.

446

Muse. sartorius, 97.

» Semimembranosus, 97.
semitendinosus, 100.
5, Sphincter ani, 347.

», Sternohyoideus, 64.

; sternomastoideus, 76.

; sternoradialis, 82.

» Submaxillaris, 62.

submentalis, 63.

; subscapularis, 78.

» temporalis, 61.
tibialis ant., 104.

” ” post., 103.

,, transverso-scapularis maior, 77.
“3 Pr minor, 77.
a transversus metacarp., 93.

ae + plant., 108.

», triceps femoris, 95.
vastus ext., 96.
int., 96.

” >

Nasal bones, 33.

» cartilages, 385.

» glands, 403.
Nephrostomes, 336.
Nerve, abducens, 171.
auditory, 172.
brachial, 183.
facial, 171.
» fifth spinal, 187.
; fourth spinal, 188.
glossopharyngeal, 172.
;» hypoglossal, 182.
laryngeal, 175.
oculo-motor, 167.

» olfactory, 167.

»; optic, 167, 405.

», pathetic, 142, 168.

» palatine, 169.

5» peroneal, 195.

+ pneumogastric, 173.

» Tadial, 186.

», sixth spinal, 188.

s Spinal, 175.

5, Structure of, 201.

» sympathetic, 197.

, third spinal, 188.

;, tibial trigeminal, 168.

vagus, 173.

N erves, 167.
of Cornea, 408.
9 x» ear, 403-
9g sMeart, 219.
lungs, 319.

» 3) oesophagus, 286.

> », Skin, 378.

» Stomach, 286.

Nervi ciliares, 169.
Nervus,coceygeus, 189.
coraco-clavicularis, 183.
cruralis, 189.

9 33

?

INDEX.

Nervus cut. antibrach. inf., 185.

» cut. antibrach. sup., 185.

» cut. dorsi pedis lat., 196.

»» ieo-hypogastricus, 189. ©
peroneus, 195.
comm. inf., 196.
lateralis, 196.
o Ls medialis, 196.
ramus accessorius, 174.
anterior, 173.
s» auricularis, 172.
5 cardiacus, 175.
» cut. axillaris, 183.
cutaneus dors., 174.
cruris lat., 196.
med., 194.

2° 9

"238 or

”
»”

“ sup., 186.
dorsalis, 185.
gastricus, 175.
-hyoideus, 172.

A »; hyomandibularis, 172.
», laryngeus, 175.
lateralis, 185.
mandibularis, 170.
maxillaris, 170.
maxillo-mandibularis,170.
muscularis, 187.
ophthalmicus, 169.
palatinus, 171.
pectoralis, 185.
posterior, 173. .
pulmonalis, 175.
scapularis, 174.
subscapularis, 185.

ve , wnaris lat., 186.

a5 + med.; 185.

,, _ tibialis, 194, 195.
Neurilemma, 201.

Nictitating membrane, 422.

' Non-medullated fibres, 202.

Nose, 383.
5 skeleton, 27, 383, 385-
Nuclear layer, inner, 416.
» outer, 416.
Nucleus abducens, 146.

» auditory, 144.

» centralis, 144.
magnus, 147, 152.
medullae oblongatae, 144.
pneumogastric, 146.
» trigeminal, 145.

Oculo-motor nerve, 167.
a nucleus, 151.
Oesophageal glands, 283.
Oesophagus, 282.
Olfactory nerve, 167.

Omosternum, 36. —
Operculo-angulare, 35.
Operculum, 25. F

Optic chiasma, 153, 155, 167.

» lobes, 14
2? nerve, I 7> 405
>> tracts, 162

Os articulare, 3

>, capitato-hamatum, 45.

+; cuboideum, 51.

;; cuneiformia, 52.

+ en ceinture, 27.

>», lunatum, 44.

» multangulum maius, 45.
a minus, 45.

»; naviculare of foot, 51.

» » _ _of hand, 45.

» occipitale basilare, 23.

superius, 23.

2? 2?

Outer nuclear layer, 416.
Ovaries, 344.
Oviducts, 304, 345.

Palatine artery, 224.
»» bones, 33.
> _‘*herves, 169

Pancreas, 300.

Papilla acustica lagenae, 400.

Papillae of skin, 370.

» _ of tongue, 380.

Parasphenoid, 26.

Pars basilaris cochleae, 400.
» commissuralis, 147, 152.
»» media, 135.

» a ue 400.

” uncularis, 143, 152.
Partes condtylaadeas: 56 :
Pathetic nerve, 142, 168.
Pectoral lymph-sac, 255.

Pericardium, 213.
Periganglionic glands, 180.
Perilymphatic space, 393.
Perineal septum, 253.
Peritonenm, 303.

Pigment of cerebellum, 149.
% s> cord, 141.
> ;, hemispheres, 160.
» >, liver, 299.
” ” medulla, 148.
” »» optic lobes, 152.
> 33 thalamencephalon, 155.
” » skin, 730.

INDEX.

447

Pigment-layer, 419.
Pineal body, 155. _

| Pituitary body, 154, 156.

Plexus, Auerbach’s, 292.

pe lateralis, 165.

is Meissner’s, 291.
Pneumogastric nerve, 146, 173.
. nucleus, 146.

ei transverse, 17.

_ Processus coracoideus, 40.

zy coronoideus, mandible, 34.
9 »» 99 Yadio-ulnar, 43.
mE mastoideus, 24.
a maticus, 30.

Prootic Gees, a:

Pterygoid bones, 31.

Pubes, 49.

Pulmo-cutaneous arch, 230.

Pulp-cavity, 279.

Purkinge’s cells, 148.

Radio-ulnar, 43.
Rami communicantes, 181, 199.
Rana aquatica, 3.

;> escnlenta, 4.

;, fiaviventris, 7.

“- gibbosa, 3:

5; innoxia, 3.

» oxyrhinus, 7, 9.

» ‘ru > 3-

>> temporaria, 7-.

ptaculum seminis, 337.

Recessus utriculi, 396.
Remak’s ganglion, 220.
Renal arteries, 333-

» portal vein, 332.

>» Velns, 333-
Reproductive organs, 341.
Retina, 414.

etinal pigment, 419.
Ritter’s fibres, 418.
Rods and cones, 416.
Roots of spinal nerves, 175.
Round bundle, 154, 159.

Saccus endolymphaticus, 395, 398.
» fenestra ovalis, 395.
” ee ee 395-
> 19. ?
Scapula, 37.
Sciatic artery, 236.
» Merve, 1920
. plexhs, IgI.

448

Sclerotic coat, 405.
Semicircular canal, ant., 396.
” ” ” sa 398.
” PB) ” O8t., 399.
Septa, of ee 252. 2
Septum medium, 139.
Serous glands of skin, 372.
Shoulder-girdle, 37.
AB -joint, 42.
Sinus, superior, 383.
Sinus venosus, 214.
Skeleton, 15.
e of nose, 27, 383, 385.

Small intestine, 286.
Sphenethmoid, 27.
Spinal cord, 135.

» ganglia, 177.

3» | "Merves, 135,175, 181.

» roots of, 175.

Spinous processes, 17.
Spleen, 302.

Squamosal bones, 30.
Sternum, 36.

Styloid cartilage, 25.
Submaxillary lymph-sac, 255.
Substantia reticulosa, 138.
Sulcus longitud. inf., 135.

” 2? sup., 135.
Superior sinus, 383. :
Supplemental toe, 5, 47, 374.
Supra-femoral lymph-sac, 260.

a, .» Septum, 259.
Suprascapula, 37.

' Suprastapedial, 26, 390.
Suspensorium, 30.
Sylvian aqueduct, 150.
Sympathetic system, 197.
Symphysis pubis, 48.
Systemic arch, 226.

Tactile sensation, organs, 377.
Taste-organs, 380.
Teeth, 278.
Tegmentum vasculosum, 395, 402. |
Temporary papillae, 370.
Testis, 341.
Thalamencephalon, 153.
Thalamus-tubercinereum strand, 154,
155, 159.
Third ventricle, 153.
Thymus gland, 320.
Thyroid gland, 322.
Tibio-femoral septum, 260.
Tibio-fibula, 49.
Toes, 5, 47, 374:
Tongue, 280.
Tonsils, 323.
Touch-corpuscles, 379.
» “Spots, 378.

INDEX.

Transverse processes, 17.
Trigeminal nerve, 168.

+ nucleus, 145.
Trochlear nerve, 168.
Truncus arteriosus, 216,
Tuberculus maius, 42.
Tympanic membrane, 389.

a9) kane, 20: Bowe
Tympanum, 389, 390. ®

Upper nasal gland, 386.
Ureters, 337.
Urinary bladder, 338.

+ organs, 332.
Uriniferous tubes, 334.
Urino-genital system, 330.
Urostyle, 21.

Utricle, 396.

.

Vagus, 173.
Valvula cerebelli, 148.
Vasa efferentia, 341.

x» YTecta, 412, 413. .
Vein, anterior abdominal, 248.
caval, 241.
orbital, 245.
* Pe tibial, 250.

», brachial, 246.
» cardiac, 249.
» caval anterior, 241.
- 3) posterior, 246.
s Cutaneous, 244.
ss dorso-lumbar, 248.
» external jugular, 241.
», facial, 245.
», femoral, 249.
+> gastric, 249.
»» haemorrhoidal, 249.
» hepatic, 247, 297.
ss hepatic portal, 249.
» iliac, 247.
» innominate, 242.
s» internal jugular, 243.
s intestinal, 249.
». jugular, external, 241.
ame ee internal, 243.
» lingual, 241.
ss Mandibular, 242.
;» median orbital, 243.
», masal, 245.
., ophthalmic, 412.
» orbital anterior, 245.
» median, 243.
$5 3, posterior, 245.
» Ovarian, 247.
oviducal, 248.
portal, 297.
»» posterior caval, 246.
»» posterior orbital, 245.

29 $3

9 37

Vein, pulmonary, 241.
» radial, 246.

' 5, Fenal, 247, 333-
» renal > 332
” sciatic, 247; 250
» Spermatic, 247
>> Splenic, 249.

+ subscapular, 244.

41.

Vena bulbi anterior, 222.

“9 ” superior, 412.

= a posterior, 222.
oy spinalis anterior, 164.
>” ” 6
superior, 164.

Ventral lymph-sac, 255.

posterior, 165.

INDEX.

449

Ventral nucleus, 155.

» Septum, 252.
Ventricle of heart, 215.
Ventricles of brain, 153.

os of | 316.
Vertebrae, et
_ structure of, 20.
Vertebral column, 16,
Vessels of brain, 162.

» of liver, 297.
Vitreous body, 420.
Voeal cords, 315.

93 88C8, 320.
Vomerine teeth, 276.
Vomers, 34.

Webs, 5, 275.
Wrist-joint, 45.

THE END.

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