oA gi Ler 
SF 
a W 
 . « fae Foe, et eg Ce Se one ‘ 
Fic. 137. — Part of a septum of the yolk-sac. Injected. 20 days’ incuba- 
tion. The free edge is above. (After Popoff.) 
Ar., Artery. St., Stomata. V.an., Longitudinal anastomoses of venous 
network. V., vein. 
