xvi ILLUSTRATIONS 



FIG. PAGE 



93. First stage of cellular secretion in placenta of cow . . . 405 



94. Ingestion and disintegration of red blood corpuscles by tropho- 



blast of sheep ......... 408 



95. Absorption of " Stabchen " by trophoblast of sheep . . 409 



96. The uterine mucosa of dog at about twenty-third day of 



pregnancy 412 



97. Ovum with zonary band of villi . . . . . .413 



98. The angioplasmode of dog at thirtieth day of pregnancy . .415 



99. The labyrinth and green border of placenta of dog at fortieth 



day of pregnancy ........ 417 



100. Transverse section of a four days' gestation sac of rabbit . 421 



101. Transverse section of a seven days' gestation sac of rabbit . 422 



102. Thickened ectoderm in rabbit, attached to placental lobe . . 424 



103. Iron granules in placenta of rabbit at eighteenth day of 



pregnancy ......... 429 



104. Glycogenic areas of rabbit's placenta at twelfth day of 



pregnancy ......... 432 



105. Inversion of germinal layers in blastodermic vesicle of mouse . 438 



106. Longitudinal sections of implantation cavity of field-mouse 



about eighth day of pregnancy . . . . . .440 



107. Longitudinal section of uterus and implantation cavity of 



guinea-pig . . . . . . . . 443 



108. Blastodermic vesicle of guinea-pig showing inversion of ger- 



minal layers ......... 444 



109. Implantation cavity of guinea-pig . . . . . . 445 



110. Implantation cavity of guinea-pig ...... 446 



111. Allantoidean diplo-trophoblast of Erinaceus .... 448 



112. Section in situ of ovum of Erinaceus ..... 450 



1 13. The extension of yolk-sac against lacunar trophoblast in 



Erinaceus 451 



114. Transverse section through uterus of Sorex at a stage when 



the blastocysts are still in the oviducts . . . .452 



1 15. Part of the anto-mesometrial wall of the uterus of Sorex . . 453 



116. Uterus and embryo of Sorex ....... 455 



117. Orifice of uterine gland of mole with trophoblastic dome . . 457 



118. Replacement of omphaloidean by allantoidean placenta . . 459 



119. Placenta of bat 461 



120. Median longitudinal section of an early human ovum, 0-4 mm. 



in length 464 



121. Diagram of the earliest human ovum hitherto described . . 468 



122. Section through the wall of the uterus in the early part of 



pregnancy ......... 469 



123. Section of a portion of the wall of the human blastocyst . . 470 



