100 



GASTRULATION 



where they become pharyngeal endoderm, he is then able to label the 

 fate of that area on other blastulae. The fate maps of various amphibia 

 are basically alike, but they are not sufficiently alike in detail to per- 

 mit plotting a universal amphibian fate map. The frog's egg is very dark 

 and it is difficult to apply vital dyes so that they will be visible on the 



Morphogenetic movements during gastrulation and neurulation as indicated by 

 changes in position of applied vital dyes. 



