STAGING OF AMPHIBIAN EMBRYOS 



63 



i^K (^^ /^ 



FOURTH CLEAVAGE - STAGE 5 

 (VEGETAL VIEW) 





^^ 



RFTH CLEAVAGE - STAGE 6 

 (l6-»- CELLS) 



^£? 



r 



1' 



SIXTH CLEAVAGE - STAGE 7 

 (32+ CELLS) 



(RANA PIPIENS) 



