Frank A. Stromsten 



467 



around the intestine is now destroyed by the atrophy of that part formed 

 by the right omphalo-mesenterie vein. Thus we have the unpaired 

 anlage of the mesenteric portal vein formed from the originally paired 

 omphalo-mesenterics. 



The splitting of the right omphalo-mcsonterie vein to form the right 



DUCT OF CUVIER 



SINUS VENOSUS. 



__GASTRIC VEIN 



Fig. 5. — Frontal reconstruction of the liver veins of an 11 mm. embryo of 

 Kinosternon pennsylvanicum. Ventral view. 



hepatic and the hepatic portion of the mesenteric portal, which was 

 begun in the last stage, is still more extensive in this stage. While, at 

 first, the right hepatic and the mesenteric portal veins are united both 

 cranially and caudally, they now become more and more separated 

 through the breaking up of these connections into sinusoids, as shown in 

 Pig. 5, in whicli this process has already Ijegun. 



