xii TABLE OF CONTENTS. 



PART II. THE HISTORY OF THE MAMMA- 

 LIAN EMBRYO. 



INTRODUCTION, pp. 307, 308. 



CHAPTER X. 



GENERAL DEVELOPMENT OF THE EMBRYO . . pp. 309 341. 



The ovarian ovum, 309, 310. The egg- membranes, 310. Ma- 

 turation and impregnation, 310 312. Segmentation, 312 314. The 

 blastodermic vesicle, 314 316. The formation of the layers, 316 

 320. The primitive streak and groove, 319, 320. The medullary 

 groove, 320, 321. The mesoblast, 321 325. The notochord, 325, 326. 

 The rudiment of the neurenteric canal, 326. Recapitulation, 326. 

 The vascular area, 326. General growth of the embryo, 327 334. 

 The human embryo, 335 341. Embryos of guinea-pig, etc. with so- 

 called inversion of the layers, 341. 



CHAPTER XI. 



EMBRYONIC MEMBRANES AND YOLK-SAC ... pp. 342 364. 



The typical development of the embryonic membranes, 342 352. 

 Vascular area of rabbit, 343 346. The yolk-sac or umbilical vesicle; 

 amnion, 343. The subzonal membrane, 346. Attachment of blasto- 

 dermic vesicle to uterine walls, 347. The formation of the chorion, 

 348. Mesoblast and blood-supply of the allantois, 348, 349. The 

 placenta, 349, 350. The fate of the embryonic membranes, 350 352. 

 Deciduate and non-deciduate type of placenta, 352. Comparative 

 history of the mammalian fatal membranes, 352 359. Foetal mem- 

 branes of Monotremata and Marsupialia, 352. The discoidal pla- 

 centa, 353, 354. The metadiscoidal placenta, 354 358. The zonary 

 placenta, 358, 359. The diffuse and polycotyledonary placenta, 359. 

 Comparative histology of the placenta, 359 363. Evolution of the 

 placenta, 364. 



