PHYSIOLOGY. ae 
external surface of the chorion, and arranged in small 
vascular tufts, which are received into depressions on 
the corresponding aspect of the uterus, and here the 
exchange of nutrition takes place. 
In the Sheep and Goat, cotyledons are present, but 
are concave instead of convex on their free surface, as 
in the Cow, 
Fic. 17. 
MATERNAL AND FETAL COTYLEDONS OF THE Cow. 
A, Pedicle of the Maternal Cotyledon; B, B, Maternal Cotyledon; C, Fcetal 
Cotyledon; D, Placental Villi; E, Chorion. 
In the Pig, there are no cotyledons present, and 
the connection resembles that seen in the Mare, with 
this exception, that the vascular tufts are very 
