190 



TEXT-BOOK OF EMBRYOLOGY. 



FIG. 161 . Surface view of area vasculosa of a rabbit embryo of 1 1 days, van Beneden and Jidin. 

 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 



Chorionic villi 



FIG. 162. Human embryo of 3.2 mm. His. The arrows indicate the direction 



of the blood current. 



