40 



THE Df:VELOPMENT OF THE CHICK 



B 



D 



Fig. 16. — Five stages of the cleavage of the hen's egg. (A, B, 

 D and E after KolUker; C after Patterson.) 



A. First cleavage furrow (x 14). The egg came from the 

 lower end of the oviduct. . , . 



B. Four-celled stage (xl7); from the uterus. 



C. Eight-celled stage (x 18). u ^ ^a^ 



D. Nine central and sixteen margmal cells (x about iOj. 



E. Late cleavage stage (x about 22). 



