DEVELOPMENT OF THE AMNION. 



661 



called the splanchnopleure, and forms the walls of the alimentary 

 canal, the allantois, and the yolk-sac. The space intervening 

 between these layers is called the pleuroperitoneal cavity. At a 

 point in front of the cephalic fold, an upward projection of soma- 



FIG. 253 B. 



e. Embryo, a. Amnion. a/. Alimentary canal. vL Vitelline membrane. 

 of. Amniotic fold. etc. Amniotic cavity, y. Yolk. al. Allantois. 



topleure takes place, conveying with it the overlying epiblast. 

 Along the sides of the embryo and behind the caudal fold, pro- 

 jections of the somatopleural mesoblast and epiblast also occur. 



