MAMMALIA. 



483 



Fig. 330.— An Embryo Horse of Six Weeks in its Membranes. 



(After EwART.) 



the reduced yolk-sac (j.^.), the enormously distended allantois {all,') forming a diffuse 

 centa, the prokalymma (a.c.'), and the villi of the serosa {t-g.). The amnion {am.) is black. 



Fig. 331. — Six Different Types of Placenta. 



ABC 



A, Discoidal. B, Dome-shaped, C, Zonary. D, Diffuse. E, Cotyledonary. 

 F, Metadiscoidal. 



