Illustrations xvii 



FIGURE 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) ....... 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 



