PRESUMPTIVE 

 EPIDERMIS 



PRESUMPTIVE 

 EURAL PLATE 



PRESUMPTIVE 

 SOMITES 



PRESUMPTIVE 

 NOTOCHORD 



PRESUMPTIV 

 ENDODERM 



t 



PRESUMPTIVE v 

 HEAD ENDODERM 



PRESUMPTIVE 

 LATERAL 

 MESODERM 



DORSAL LIP 

 BLASTOPORE 



PRESUMPTIVE 

 EPIDERMIS 



PRESUMPTIVC 

 NEURAL PLATE 



PRESUMPTIVE 

 SOMITES 



PRESUMPTIVE 

 LATERAL 

 MESODERM 



PRESUMPTIVE 

 NOTOCHORD 



PRESUMPTIVE 



HEAD 



ENDODERM 



ENDODERM DORSAL LIP 

 BLASTOPORE 



Fig. 26. Maps of the presumptive values of the regions on the surface of 

 the early amphibian gastrula. The maps of various species of amphibians are 

 different, and this diagram merely gives relative positions and sizes of the 

 presumptive structures. Upper figure: A top view of the early gastrula with the 

 dorsal lip as a point of orientation. Lower figure: A side view of the same. 



60 



