Illustrations xix 



FIGURB PAGE 



79. Diagram of the Venous Circulation after the 



Commencement of Respiration by Means of 



the Lungs. (After Foster and Balfour) . 257 



80. Egg of Chick with Embryo and Foetal Appen- 



dages. (After Parker and Haswell from 

 Duval) f 266 



81. Two Views of the Heart of a Chick on the 



Fifth Day of Incubation : A Ventral ; B 

 Dorsal View. (After Foster and Balfour) . 268 



82. Heart of a Chick on the Sixth Day, Ventral 



View. (After Foster and Balfour) . . 269 



83. Transverse Section through the Dorsal Region 



of a Chick Embryo with about Twenty-eight 

 Segments. (After Minot) . . . .271 



84. Section through an Advanced Embryo of a 



Rabbit, to Show how the Pericardial Cavity 

 Becomes Surrounded by the Pleural Cavi- 

 ties. (After Foster and Balfour) . . 274 



85. Full-grown Human Ovum. (From Minot, 



after W. Nagel) 285 



86. Human Spermatozoa. (From Minot, after 



Retzius) 287 



87. Ovum of Bat, with Four Blastomeres. (From 



Minot, after Van Beneden and Julin) . 289 



88. Totally Segmented Ovum of a Rabbit. (From 



Marshall, after Van Beneden) . . . 291 



89. Early Stage in the Formation of the Blasto- 



dermic Vesicle of a Rabbit. (From Mar- 

 shall, after Van Beneden) . . . .291 



