REPRODUCTION. 



91 



a somewli^t columnar epithelium, are everywhere in contact 

 with the foetal villi, which are themselves covered with a flat 

 epithelium. 



Fig. 94. Fia. 95. 



Pigs. 91 to 97.— Diagralnniatic representation of the minute stmctnre of the placenta 

 (Foster and Balfour, after Turner). F, fcetal; M, maternal placenta; «, epithelium 

 of chorion; e', epithelinm of maternal placenta; d, foetal blood-vessels; d', mater- 

 nal blood-vessels; », villus. 



Fig. 91. — Placenta in most generalized form. 



Fig. 92.— Structure of placenta of a pig. 



Fig. 98.— Of a cow. 



Fig. 94.— Of a fox. 



Fig. 95.— Of a cat. 



In the case of the sloth, with a more discoidal placenta, the 

 dilatation of capillaries and the modification of epithelium are 

 greater. 



