400 OUTLINES OF CHORDATE DEVELOPMENT 



ch 



C 



D 



nc 



.ch 



E 



FIG. 161. Diagrams of sagittal sections through the human blastodermic 

 vesicle, showing the formation of the amnion and trophoderm. A-D, after 

 Keibel and Elze. E, From McMurrich (Development of the Human Body), 



