10 



COMPARATIVE ANATOMY 



&F/. 



B 



C 



Fig. S, A, I',, AND ('. PIAOKA.MS ILU T STI:ATIN<! THE FORMATION OK THE ASJNJON, 

 ALLANTOIS, AM> YOLK-SAC. A AND I'., IN F>ONCITI-IIN AI, SKI Ti<r; ; C, IN 

 TRANSX KIISK SIOCTION. 



A, amnion ; .IF, amniotic fold: Alt, aimiiolii- cavity: At, allantois ; <J, noto- 

 chord ; l)h, alimentary cavity; /><>, y<> k-sa : A\ liody "t embryo; M, 

 medullary cord : />}>, ccclonu' ; ", somatopleuve ; ', splanchnopleure ; t, vitello- 

 jntestinal duct. 



