Talk:Vertebrate Embryology - A Text-book for Students and Practitioners (1893) Illustrations
List of Illustrations
Introductory Chapter
1. Stages in the maturation of the egg of the frog. (After O. Sclmltze)
2. Segmentation of the egg of AmphLoxus. (After Hatschek)
3. Segmentation of the frog's egg
4. The hen's egg, freshly laid
5. Segmentation of the germinal disc of the hen's egg. (After Coste and Duval)
6. Later stage in the segmentation of the germinal disc of the hen's egg. (After Coste and Duval)
7. Vertical section of the germinal disc of the hen's egg at the close of segmentation. (After Duval)
8. Vertical section of early larval stage of Amphioxus. (After Hats chek)
9. Horizontal section of early larval stage of Amphioxus. (After Hats chek)
10. Transverse section through the head of a chick embryo at the end of the first day of incubation .24
Amphioxus
11. Young specimen of Amphioxus, viewed as a transparent object. (From Marshall and Hurst) 38
12. Transverse section through the anterior part of the pharynx of an adult Amphioxus. (From Marshall and Hurst) .... 39
13. Transverse section through the posterior part of the pharynx of an adult female Amphioxus. (From Marshall and Hurst) . . 42
14. Segmentation of the egg of Amphioxus. (After Hatschek) . . 50
15. Formation of the gastrula of Amphioxus. (After Hatschek) . . 63
16. Later stage in the formation of the gastrula of Amphioxus. (After Hatschek) 53
17. Further stage in the formation of the gastrula of Amphioxus. (After Hatschek) .'.'..' 54
18. Completion of the gastrula of Amphioxus. (After Hatschek) . . 54
19. The gastrula of Amphioxus, bisected vertically. (After Hatschek) . 5(5
20. The gastrula of Amphioxus, bisected horizontallj*. (After Hatschek) 5(5 21-24. Transverse sections across the bodies of Amphioxus embryos, showing the mode of formation of the nervous system and of the mesoblastic somites. (After Hatschek) . . . , 58
25. Amphioxus embryo at the time of hatching; bisected vertically. (After Hatschek) 59
26. Amphioxus embryo at the time of hatching ; bisected horizontally. (After Hatschek) 59
27. Amphioxus embryo shortly after hatching ; seen in optical section from the right side. (After Hatschek) 62
28 and 29. Transverse sections of Amphioxus embryos shortly after hatching ; showing stages in the formation of the notochord and mesoblastic somites. (After Hatschek) 64
30. Amphioxus embryo with nine pairs of mesoblastic somites, seen in optical section from the right side. (After Hatschek) . . 66
31. Amphioxus embryo with nine pairs of mesoblastic somites, seen in horizontal section. (After Hatschek) 66
32. Transverse section through the middle of an Amphioxus embryo with nine pairs of mesoblastic somites. (After Hatschek) . . 67
33. Amphioxus embryo with fourteen pairs of somites ; seen in optical section from the right side. (After Hatschek) .... 6!)
34. Amphioxus larva at the commencement of the second or ' larval ' period of development. (After Hatschek) 74
35. Young Amphioxus during the ' adolescent ' period. (After Kowa levsky) "4
36. The anterior end of an Amphioxus larva with four primary gill-slits, seen from the left side. (After Lankester and Willey) . . 76
37. The anterior end of an Amphioxus larva with fourteen primary gill slits, seen from the right side. (After Willey) . . . 76
38. The anterior end of an Amphioxus larva with thirteen primary and eight secondary gill-slits, seen from the right side. (After Willey) 77
39. The anterior end of an Amphioxus larva with twelve primary gill slits, of which the first and twelfth are disappearing, and eight secondary gill-slits ; seen from the ventral surface. (After Willey) 78
40. Diagrammatic transverse section across an Amphioxus larva with eleven or twelve primary gill-slits, but no secondary ones. (Slightly modified from Lankester and Willey) .... 82
41. Diagrammatic transverse section through an advanced Amphioxus
larva with fully formed atrial cavity. (Slightly modified from Lankester and Willey, and from Boveri) 83
42. Diagrammatic transverse section across the intestinal region of an Amphioxus larva with five primary gill-slits. (After Hatschek) 85
43. Diagrammatic transverse section across a young Amphioxus imme diately after the completion of the larval period. (After Hatschek) 86
The Frog
44. Various stages in the development of the frog. (From Brehm'3 'Thierleben') 93
45. Stages in the maturation of the egg of the frog. (After 0. Schultze) OS 46-48. Segmentation of the frog's egg 101
49. The blastula stage in the development of the frog's egg . . . 103
50. The frog's egg at the close of segmentation 103
51. Median sagittal section of a frog embryo, showing the spreading of the epiblast, and the commencing formation of the mesenteron. 104 ~i2. Sagittal section of a frog embryo during the formation of the mesenteron 106
53. Horizontal section of a frog embryo during the formation of the mesenteron 107
54. Sagittal section of a frog embryo just before the disappearance of the segmentation cavity 108
55. Sagittal section of a frog embryo after the disappearance of the segmentation cavity and completion of the mesenteron . . 109
56. A transverse section through the middle of a frog embryo at about the stage represented in Fig. 55 110
57. A frog embryo at the time of appearance of the neural folds : seen from the dorsal surface 113
58. Stages in the early development of the frog embryo, seen obliquely from the hinder end. (From a series of wax models by Dr. F. Ziegler of Freiburg i/B) 114
59. Transverse section through a frog embryo, showing the neural folds shortly before they meet each other to complete the neural tube 115
60. Sagittal section of a frog embryo, shortly before closure of the blastopore . . 116
61. Sagittal section of a frog embryo, shortly after closure of the blasto pore and formation of the anus 117
62. The brain of the adult frog : dorsal surface 119
63. The brain of the adult frog : ventral surface 119
64. Sagittal section of the head end of a tadpole, just before the opening of the mouth 120
65. Sagittal section through the head and body of a tadpole of 12 mm. length, at the time of appearance of the hind limbs . . .121
66. Diagrammatic horizontal section of a 12 mm. tadpole, at the time of appearance of the hind limbs 135
67. Transverse section through the head of a tadpole of 6i mm. length, about the time of hatching 137
68. Transverse section across the posterior part of the head of an adult frog, showing the position and relations of the auditory organs, Eustachian tube, and hyoid apparatus 144
69. Sagittal section through a tadpole at the time of hatching . . 146
70. Transverse section across the middle of the length of a frog embryo 3\ mm. in length . . . 147
71. Horizontal section of the head and body of a 12 mm. tadpole . . 155
72. Side view of a tadpole at the time of hatching 157
73. Ventral view of a tadpole at the time of hatching .... 157
74. Horizontal section of a tadpole at the time of hatching . . .158
75. Transverse section through the head of a 12 mm. tadpole . . . 162
76. Diagrammatic figure of a 12 mm. tadpole, about the time of appear ance of the hind limbs . 166
77. Diagrammatic figure of the head and anterior part of the body of a 7 mm. tadpole shortly after hatching ; showing the branchial blood-vessels from the ventral surface ..... 170
78. Diagrammatic figure of the same embryo as in fig. 77, seen from the right side ........... 170
79. Diagrammatic transverse section across the head of a 7 mm. tadpole 171
80. Diagrammatic figure of the head of a 12 mm. tadpole from the right side, showing the heart and branchial blood-vessels . . .173
81. Diagrammatic figure of the arterial system of an adult frog . . 17s
82. Transverse section through the body of a tadpole at the time of hatching, showing the nephrostomes of the head-kidney . . 187
83. Diagrammatic figure of a 12 mm. tadpole dissected from the ventral surface, to show the heart and branchial vessels, and the headkidneys and commencing Wolffian bodies ..... 189
84. Transverse section across a 12 mm. tadpole, passing through the middle of the head-kidney ........ 1 00
85. A 40 mm. tadpole dissected from the ventral surface, to show the heart, the branchial vessels, and the urinary and reproductive organs ............ 193
86. A tailed frog, during the metamorphosis, dissected from the ventral surface to show the urinary and reproductive organs . . .193
87. Transverse section through the hinder part of the body of a tailed frog during the metamorphosis ....... 1 94
88. Transverse section through the anterior part of the body of a tailed frog during the metamorphosis ....... ] 95
89. Sagittal section of a tailed frog during the metamorphosi3 . . 200
90. The skull of a 12 mm. tadpole, seen from the right side . . . 202
91. The skull of a 12 mm. tadpole, from the dorsal surface . . . 202
92. The skull of a 12 mm. tadpole, from the ventral surface . . . 202
93. The skull of a tailed frog, towards the close of the metamorphosis, seen from the right side . . . ..... 208
94. The skull of an adult frog, seen from the right side .... 209
95. The skull of an adult frog, seen from the ventral surface . . .210
96. The skeleton of the frog, seen from the dorsal surface . . . 214
The Chick
97. The hen's egg at the time of laying ....... 221
98. The yolk of a hen's egg at the thirty-sixth hour from the commence ment of incubation ......... 223
99. The yolk of a hen's egg at the end of the third day of incubation . 224
100. The hen's egg at the end of the fifth day of incubation . . . 225
101. The hen's egg at the end of the ninth day of incubation . . . 227
102. An early stage in the segmentation of the germinal disc of the hen's
egg. (After Coste and Duval) ....... 233
103. A later stage in the segmentation of the germinal disc of the hen's
egg. (After Coste and Duval) ....... 233
104. Section through the germinal disc and adjacent parts of the yolk of
a hen's egg about the middle of its stay in the uterus. (After Duval) ............ 234
105. Vertical section of the blastoderm and adjacent part of a hen's egg
towards the close of segmentation. (After Duval) . . . 234
106. Vertical section of the blastoderm and adjacent part of the yolk of a hen's egg at the time of laying, but before the commencement of incubation. (After Duval) 235
107. A diagrammatic figure of the blastoderm of a hen's egg about the
twentieth hour of incubation. (In part after Duval) . . 238
108. Transverse section across the blastoderm of a hen's egg about the
twentieth hour of incubation 239
109. A diagrammatic figure of the blastoderm of a hen's egg about the
twenty-fourth hour of incubation. (In part after Duval) . . 241
110. A chick embryo at the twenty-fourth hour of incubation ; seen from
the dorsal surface 248
111. A chick embryo at the thirty-sixth hour of incubation ; seen from
the dorsal surface 251
112. A median longitudinal, or sagittal, section of a chick embryo at the
thirty-sixth hour of incubation 251
113. A chick embryo at the end of the third day of incubation . . 253
114. A median longitudinal, or sagittal, section through a chick embryo
at the end of the third day of incubation 255
115. A chick embryo at the end of the fifth day of incubation . . 257 11(5. A median longitudinal, or sagittal, section of the head and anterior
part of the neck of a chick embryo at the end of the eighth day
of incubation 258
117. Transverse section across the body of a chick embryo at the twenty fourth hour of incubation 261
118. Transverse section across the head of a chick embryo at the twenty fourth hour of incubation 263
119. Transverse section across the head of a chick embryo at the forty third hour of incubation 264
120. Transverse section across the head of a chick embryo at the forty third hour of incubation, the section passing through the commencing auditory pits and the heart 265
121. Transverse section across the head of a chick embryo at the forty eighth hour of incubation . 276
122. Transverse section across the fore-brain and eye of a chick embryo
at the sixtieth hour of incubation 277
123. A median longitudinal, or sagittal, section through a chick embryo
at the end of the fifth day of incubation ..... 282
1 24. A section through the head of a chick embryo at the end of the third
day of incubation 284
125. The head of an embryo chick at the end of the fifth day of incuba tion 287
126. The head of an embryo chick at the end of the seventh day of in cubation 288
127. The anterior end of a chick embryo at the thirty-sixth hour of incu bation 299
128. A diagrammat'c figure showing the arrangement of the blood vessels in a chick embryo at the end of the fifth day of incubation 304
129. A transverse section across the body of a chick embryo at the forty eighth hour of incubation 317
130. The left half of ths skeleton of the common fowl. (From Marshall
and Hurst) 325
131. The skull of a chick embryo at the end of the eighth day of incu bation 329
132. The skull of the fowl, from the right side. (From Marshall and
Hurst) 331
The Rabbit
133. Section through part of the ovary of an adult rabbit . . . 347 131. A fully formed ovum of a rabbit, shortly before its discharge from
the ovary. (After Bischofif) 350
135. A rabbit's ovum, from the upper end of the oviduct, after extrusion
of the two polar bodies. (After Bischoff) 350
136. A rabbit's ovum, about twenty-two hours after copulation, showing
division of the ovum into two cells. (After Bischoff) . . 353
137. A rabbit's ovum about the middle of the third day, showing the
morula stage, shortly before the completion of segmentation. (After Bischoff) 353
138. A rabbit's ovum seventy hours after copulation, showing the condi tion at the close of segmentation. (After Van Beneden) . . 354
139. A rabbit's ovum seventy-five hours after copulation, showing the
first stage in the formation of the blastodermic vesicle. (After Van Beneden) 354
140. Section of the blastodermic vesicle of a rabbit at the end of the
fourth day. (After Van Beneden) 355
141. A vertical section across the embryonal area of the blastodermic
vesicle of a rabbit at the end of the fifth day. (After Kolliker) 359
142. A transverse section across the hinder part of the embryonal area of
a rabbit embryo at the end of the seventh day. (After Kolliker) 359
143. The blastodermic vesicle of a rabbit at the end of the seventh day.
(Modified from Kolliker) . 360
144. The embryonal area of a rabbit at the middle of the eighth day.
(Modified from Kolliker) . . 360
145. A rabbit embryo and blastodermic vesicle at the end of the ninth day 363
146. A median longitudinal, or sagittal, section through a rabbit embryo
and blastodermic vesicle at the end of the ninth day. (In part after Van Beneden and Julin) 364
1 47. A rabbit embryo and blastodermic vesicle at the end of the tenth
day. (In part after Van Beneden and Julin) .... 365
148. A rabbit embryo and fostal appendages at the end of the twelfth
day. (In part after Van Beneden and Julin) .... 366
149. A rabbit embryo of the twentieth day 367
150. A median longitudinal, or sagittal, section through a rabbit embryo
at the end of the twelfth day 373
151. A median longitudinal, or sagittal, section through the head of a
rabbit embryo of the eighteenth day 375
152. The brain of an adult rabbit, dissected from above. (From Marshall
and Hurst) 377
153. A median longitudinal, or sagittal, section of the brain of an adult rabbit. (From Marshall and Hurst) 378
154. The brain of an adult rabbit from the ventral surface. (From Marshall and Hurst) 383
155. A transverse section across the head of a rabbit embryo of the fourteenth day 388
156. A transverse section across the head of a rabbit embryo of the twenty-first day 391
157. A diagrammatic section across the head of an adult rabbit, to show the relations of the internal ear, tympanic cavity and membrane, and the auditory ossicles. (From Marshall and Hurst) . . 394
158. A transverse section across the head of a rabbit embryo at the end of the eleventh day, the section passing through the medulla oblongata, the ears, and the pharynx 395
159. A transverse section across the head of a rabbit embryo of the fifteenth day, passing through the medulla oblongata, the ears, and the pharynx 396
160. A diagrammatic view of an adult male rabbit from the left side. (From Marshall and Hurst) 401
161. A rabbit embryo at the end of the twelfth day, seen from the right side 402
162. The skull of the rabbit from the right side. (From Marshall and
Hurst) 405
163. A transverse section across the thorax of a rabbit embryo of the
sixteenth day 409
164. A transverse section across the body of a rabbit embryo of the
early part of the tenth day, showing the supposed epiblastic origin of the Wolffian duct. (After Hensen) .... 422
165. A transverse section across the body of a rabbit embryo at the end
of the eleventh day . 423
166. A transverse section across the hinder part of the body of a rabbit
embryo of the fourteenth day ....... 424,
167. Selected vertebrae from the rabbit. (From Marshall and Hurst) . 431
168. A transverse section across the uterus, with the contained blasto dermic vesicle, of a rabbit at the end of the seventh day. (In part after Duval) 436
169. A transverse section across the uterus and the contained blasto dermic vesicle of a rabbit at the end of the ninth day. (In part after Duval) 439
170. A transverse section across the uterus and the contained embryo
of a rabbit at the end of the nineteenth day .... 443
The Human Embryo
171. Part of a vertical section of the ovary of a new-born infant. (From Strieker's ' Histology') 451
172. Front view of Reichert's ovum. (From Kolliker, after Reichert) . 472
173. Side view of Reichert's ovum. (From Kolliker, after Reichert) . 472
174. Diagrammatic section of Reichert's ovum. (From His) . . . 473
175. A longitudinal section of the uterus, with an ovum in situ, esti mated as about the thirteenth day. (After Kollmann) . . 474
176. Outline figure of a human embryo lettered by Professor His, E, and estimated as about the thirteenth day. (From His) . . . 477
177. Outline figure of a human embryo described by Allen Thomson, and estimated as about the thirteenth day. (From His) . . . 477
178. Outline figure of a human embryo, lettered by Professor His, S R, and estimated as of the thirteenth day. (From His) . . 477
179. Human embryo lettered by Professor His, S R, and estimated as of the thirteenth day. (After His) 478
180. Human embryo of about the thirteenth day, from the left side. (After V. Spee) 479
181. The same embryo as in Fig. 180, from the dorsal surface. (After V. Spee) 479
182. Transverse section across the head end of the human embryo shown in Figs. 180 and 181. (After V. Spee) . . . . .480
183. Transverse section across the middle of the body of the human embryo shown in Figs. 180 and 181. (After V. Spee) . . 480
184. Transverse section across the hinder end of the human embryo shown in Figs. 180 and 181. (After V. Spee) . . . .480
185. Human embryo of about the fourteenth day, from the right side. (After Kollmann) 481
186-188. Diagrammatic longitudinal sections through human embryos, representing hypothetical stages intermediate between Reichert's ovum and His' embryos, E or S R. (From His) . . . . 484
189. Outline figure of a human embryo lettered by Professor His, Lg, and estimated as fifteen days old. (From His) .... 487
190. Outline figure of a human embryo lettered by Professor His, Sch, and estimated as fifteen days old. (From His) .... 487
191. Outline figure of a human embryo lettered by Professor His, II, and estimated as eighteen days old. (From His) . . . .487
192. Outline figure of a human embryo figured by Allen Thomson, and probably about eighteen days old. (From His) . . . 487
193. Outline figure of a human embryo lettered by Professor His, B B, and estimated as about eighteen days old. (From His) . . 487
194. Outline figure of a human embryo lettered by Professor His, Kin, and estimated as about twenty days old. (From His) . . 487
195. Outline figure of a human embryo lettered by Professor Hi.=, Lr, and estimated as twenty or twenty-one days old. (From His) . 487
196. Human embryo at the commencement of the third week. (From His, after Coste) 488
197. Human embryo lettered by Professor His, Lg, and estimated as fifteen days old. (After His) 489
198. Human embryo lettered by Professor His, Lr, and estimated as twenty or twenty-one days old. (After His) .... 491
199. Outline figure of a human embryo figured and described by Coste, and estimated as about twenty-three days old. (From His) . 493
200. Outline figure of a human embryo lettered by Professor His, a, and estimated as about twenty-three days old. (From His) . . 493
201. Outline figure of a human embryo figured and described by Allen Thomson, and estimated as about twenty-three days old. (From His) 493
202. Outline figure of a human embryo lettered by Professor His, B, and estimated as twenty-seven days old. (From His) . 493
203. Outline figure of a human embryo lettered by Professor His, A, and estimated as twenty-seven days old. (From His) . . . 493
204. Human embryo lettered by Professor His, A, and estimated as
twenty-seven days old. (After His) 494
205. Outline figure of a human embryo lettered by Professor His, Rg, and
estimated as thirty-two or thirty-three days old. (From His) . 497
206. The under surface of the head of a human embryo lettered by Pro fessor His, Hn, and estimated as about twenty-nine days old. (After His) 498
207. The under surface of the head of a human embryo lettered by Pro fessor His, C.IL, and estimated as about thirty-four days old. (After His) 498
208. The left ear of a human embryo lettered by Professor His, Br. 2, and estimated as thirty-five days old. (From His) .... 500
209. The left ear of a human embryo lettered by Professor His, Dr, and estimated as thirty-eight days old. (From His) .... 600
210. A pregnant uterus of about the fortieth day. (From Kolliker, after Coste) 501
211. Outline figure of -a human embryo about the middle of the sixth week. (From His) . 503
212. Outline figure of a human embryo at the end of the second month. (From His) . . - . .504
213. Head of a human embryo at the end of the seventh week. (After His) 505
214. Head of a human embryo at the end of the second month. (After His) . . . . 505
215. The head and fore part of the body of a human embryo lettered by Professor His, Lr, and estimated as twenty or twenty-one days old. (After His) 511
216. Human embryo lettered by Professor His, Pr, and estimated as twenty-eight days- old. The brain is exposed from the left side, and the body of the embryo has been dissected to show the heart and aortic arches and the alimentary canal. (After His) 512
217. The brain of a human embryo lettered by Professor His, ZW, and estimated as about the middle of the eighth week. (After His) 513
218. A human fcetus three months old, dissected from the dorsal surface to expose the brain and spinal cord. (From Kolliker) . . 514
219. The brain of a human foetus three months old, from the right side. (From Kolliker) 515
220. The brain of a human foetus three months old, dissected from the dorsal surface. (From Kolliker) 515
221. The brain of a human foetus three months old, from the ventral surface. (From Kolliker) . . 515
222. The brain and spinal cord of a human foetus four months old, from the dorsal surface. (From Kolliker) 515
223. The brain of a human fcetus six months old, from the right side. (From Kolliker) 515
224. The brain of a human fcetus of the fifth month, bisected, and seen from the inner surface. (From Kolliker) 518
225. A transverse section through a portion of the wall of the spinal cord of a human embryo at the beginning of the fourth week. (After His) 522
226. A diagrammatic transverse section across the spinal cord of a human embryo of the fourth week. (After His) 525
227. A diagrammatic figure of a human embryo lettered by Professor His, Ko, and estimated as thirty-one days old. The figure shows the brain and spinal cord, and the cranial and spinal nerves. (After His) 529
228. Transverse section across the medulla oblongataof a human embryo lettered by Professor His, Ko, and estimated as thirty-one days old. The section passes through one of the roots of the hypoglossal nerve, and through both the motor and sensory roots of the pneumogastric nerve. (After His) 532
229. The left auditory vesicle of a human embryo four weeks old. (After W. His, jun.) 42
230. The left auditory vesicle of a human embryo five weeks old. (After W. His, jun.) 542
231. The left auditory vesicle, or internal ear, of a human embryo of the eighth week. (After W. His, jun.) 543
232. Human embryo lettered by Professor His, Lg, and estimated as fifteen days old. The brain and heart are exposed from the right side ; the alimentary canal and the yolk-stalk are represented in median sagittal section. (After His) .... 545
233. Outline figure of the alimentary canal of a human embryo lettered by Professor His, Pr, and estimated as twenty-eight days old. (From His) 546
234. Outline figure of the alimentary canal of a human embryo lettered by Professor His, Sch, and estimated as thirty-five days old. (From His) 547
235. Outline figure of the alimentary canal of a human embryo estimated as thirty-two days old. (From His) 548
236. Outline figure of the alimentary canal of a human embryo estimated
as thirty-five days old. (From His) 548
237. The floor cf the pharynx of a human embryo fifteen days old, seen
from above. (After His) 550
238. The floor of the pharynx of a human embryo twenty-three days old,
seen from above. (After His) 551
239. The floor of the pharynx of a human embryo twenty-eight days
old, seen from above. (After His) 552
240. The head and neck of a human embryo thirty-two days old, seen
from the ventral surface. (After His) 553
241. The roof of the mouth of a human embryo about two and a half
months old, showing the formation of the palate. (After His) . 554
242. The tongue and the floor of the mouth of a human embryo at the
end of the second month. (After His) 556
243. Human embryo lettered by Professor His, Bl, and estimated as
twenty-three days old. The brain and spinal cord are exposed from the right side : and the body is dissected to show the heart, the blood-vessels, and the alimentary canal. (After His) 567
LIST OF ILLUSTRATIONS. xxiii
FIG. PAGB
244. The dorsal half of the heart of a human embryo twenty-eight days
old, seen from within. (After His) 569
245. The aortic arches of a human embryo thirty-two days old, from the
left side. (After His) 576
246. The aortic arches of a human embryo thirty-five days old, from the
left side. (After His) 577
247. The liver, and the veins in connection with it, of a human embryo
twenty-four or twenty-five days old, seen from the ventral surface. (After His) 580
248. Transverse section across the body of a human embryo estimated
as fourteen days old. (After Kollmann) 689
249. The adult ovary, parovarium and Fallopian tube. (From Quain's
4 Anatomy,' after Kobelt) 595
250. The external genitalia of a human embryo of about the ninth week.
(From Kolliker, after Ecker) 596
251. The external genitalia of a human embryo of about the tenth week.
(From Kolliker, after Ecker) 596
252. The external genitalia of a male human embryo towards the end of
the third month. (From Kb'lliker, after Ecker) .... 597
253. The external genitalia of a female human embryo towards the end
of the third month. (From Kolliker, after Ecker) . . . 597
254. A diagrammatic section of the pregnant human uterus at the
seventh or eighth week. (From Quain's ' Anatomy,' after Allen Thomson) 600
255. A pregnant human uterus of about the twenty-fifth day. (From
Quain's ' Anatomy,' after Coste) 608
