CHAPTER VIII. AVES. Pp. 145-201.✦

Segmentation and formation of the layers, pp. 145-166. General history of the germinal layers, pp. 166-169. General development of the embryo, pp. 169-180. Foetal membranes, pp. 185-199. Amnion, pp. 185-191. Allantois, pp. 191-193. Yolk-sack, pp. 193-199.

CHAPTER IX. REPTILIA. Pp. 202-213.✦

Lacertilia, pp. 202-209. Segmentation and formation of the layers, pp. 202-207. General development of the embryo, p. 208. Embryonic membranes and yolk-sack, pp. 208-210. Ophidia, p. 210. Chelonia, pp. 210-212.

CHAPTER X. MAMMALIA. Pp. 214-274.✦

Segmentation and formation of the layers, pp. 214-227. General growth of the embryo, pp. 227-232. Embryonic membranes and yolk-sack, pp. 232-239. Comparative history of the Mammalian foetal membranes, pp. 239-257. Comparative histology of the placenta, pp. 257-259. Evolution of the placenta, pp. 259-261. Development of the Guinea-pig, pp. 262-265. The human embryo, pp. 265-270.

CHAPTER XI. COMPARISON OF THE FORMATION OF THE GERMINAL LAYERS AND OF THE EARLY STAGES IN THE DEVELOPMENT OF VERTEBRATES. Pp. 275-310.

Formation of the gastrula, pp. 275-292. The formation of the mesoblast and of the notochord, pp. 292-300. The epiblast, pp. 300-304. Formation of the central nervous system, pp. 301-304. Formation of the organs of special sense, p. 304. Summary of organs derived from the three germinal layers, pp. 304-306. Growth in length of the Vertebrate embryo, pp. 306-309. The evolution of the allantois and amnion, pp. 309, 310.

CHAPTER XII. OBSERVATIONS ON THE ANCESTRAL FORM OF THE CHORDATA. Pp. 311-330.✦

General considerations, pp. 311-316. The medullary canal, pp. 316, 317. The origin and nature of the mouth, pp. 317-321. The cranial flexure, pp. 321, 322. The postanal gut and neurenteric canal, pp. 322-325. The body-cavity and mesoblastic somites, p. 325. The notochord, pp. 325, 326. Gill clefts, pp. 326, 327. Phylogeny of the Chordata, pp. 327-329.