290 



Basic Structure of Vertebrates 



SOMATOPLEURE 



AMNION CAVITY\ 



EXTRA-EMBRYON. ' 

 COELOM 



SEROSA (CHORION) 



AMNION 

 XOELOM 



AMNION CAVITY. 

 AMNION. 



SEROSA 



FOETAL PLACENTA 

 ALLANTOIS 



ALLANTOIC 

 STALK 



SPLANCHNOPLEURE 



Fig. 239. Diagrams illustrating the development of the amnion and allantois. 

 (Top) Earlier stage; section transverse to long axis of embryo. (Bottom) Later 

 stage; sagittal section of embryo. (After Kingsley. Courtesy, Neal and Rand: 

 "Chordate Anatomy," Philadelphia, The Blakiston Company.) 



