736 



ANATOMY OF VERTEBRATES. 



The outer surface of the chorion of the Tapir is beset with 

 short linear series of small compressed foliate processes, dividing 

 into from three to six leaflets, upon or within which the foetal 

 capillaries ramify : the inner surface, when the allantoic non- 

 vascular layer or endochorion is removed, is reticulate through 

 the division of the allantoic vessels, sending off the capillaries 

 to the foliate villi. 



The clustered arrangements of the placental capillaries is more 

 marked in the Sow than in the Mare : when uninjected they 



Impregnated uterus of Mare. cxxn'. 



appear as white subcircular spots scattered over the outer surface 

 of the chorion : but when the allantoic veins are filled, these are 

 seen to form plexules in the centre of each spot. The uterine 

 veins have a corresponding arrangement. The uterine arterial 

 capillaries form a fine network, the meshes receiving the villo- 

 sities which carry the foetal arterial capillaries ; whence it might 

 seem that the nutrition of the foetus was effected principally at 

 the points of contact of the foetal with the maternal venules, 



