40 



THE DEVELOPMENT OF THE CHICK 



1^ 



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 (x 17) ; from the uterus. 



C. Eight-celled stage (x 18). 



D. Nine central and sixteen marginal cells (x about 16). 



E. Late cleavage stage (x about 22). 



