462 



ZOOLQGY FOR MEDICAL STUDENTS CHAP, xiv 



it will be noticed that it is situated not over the centre of the embryonic 

 body but towards its hind end indicating that the growth of the amniotic 



v.c. 



ua. 



ff. 



- TTIJS 



FIG. 194. 



>wl embryo viewed asa transparent object, a.c, li<Uc ot amnioti ; am, aniiiimi ; 

 II, l.'-.ut; ;.<;, mr,(lrtm Moment-,; nt, otocyst ; s, indications of pre-otic nu'sodcrm 

 (?) ; v.a, vitellinc artery ; v.c, visceral cleft II ; * portion of splanchnopleurc buI^iiiK 

 tin- yolk, forming a recess in tfhich lies the head of the embryo. 



fold does not take place at an equal rate all round. As a matter of 

 fact it first appears and grows most rapidly at the head end forming a 

 hood which grows buck over the head region. The hinder and then the 



