240 



TEXT-BOOK OF EMBRYOLOGY. 



FlG. 214. — Surface view of area vasculosa of a rabbit embryo of n days, van Beneden and Julin. 

 The vessel around the border is the sinus terminalis; the two large vessels above the embryo are 

 the vitelline (omphalomesenteric) veins; the two large vessels converging below the embryo 

 are the vitelline (omphalomesenteric) arteries. 



Dors, aortic root 

 and aortic arches 



Ant. cardinal vein 



Amnion 

 Post, cardinal vein 



Aorta 



fit '■■ l-/^)-' " 



Belly stalk 



Chorionic villi 





v u " U 



Fig. 215. — Human embryo of 3.2 mm. His. The arrows indicate the 

 direction of the blood current. 



