Lt 
26. 
Ors ATS 
Ros 
2 
¢ 
Fie. 136. — Circulation in the embryo and yolk-sac of an embryo of about 
40 s, showing the later development of the lateral and intermediate vitel- 
line veins. Reduction of vena terminalis (marginal vein). Almost com- 
plete atrophy of the right anterior vein. Injected. (After Popoff.) 
1, Marginal vein. 2r, 21, Right and left anterior vitelline veins. 3, 
Arch of aorta. 4, Left posterior cardinal vein. 5r, 51, Right and 
left omphalomesenteriec veins. 6, Aorta. 6a, Left dorsal aorta. 7, 
Vitelline artery. 8, Posterior vitelline vein. 9, Vascular network in the 
allantois. 
