MORPHOLOGY OF ANIMALS 



Fig. 4. Early Development of Frog's Egg. A, Late Cleavage; R, Blastula; C, Gastrula ; D, E, 

 F, young embryos. The animal pole of the egg is marked by two small polar bodies. The 

 left side of each figure is anterior (a), right posterior {p), upper side ventral (jy), lower side 

 dorsal id); bp, blastopore; c, notochord or area of embryo from which it comes; E, enteron ; 

 en, endoderm ; m, mesoderm; n, neural tube, or plate, or area from which it comes; jc, 

 segmentation cavity or blastocoel. 



