100 



THE TOPOGENESIS OF THE EMBRYO 



c/orsffd/ 



/'^/^//Vc?/ 



Fig. 35. Diagrammatic projection of the organ primordia of a 

 urodele embryo onto the blastula surface, seen (a) from the vege- 

 tative pole, and (b) from the left side. Coarse hatching := epidermis, 

 fine hatching rzi neural plate, closely dotted = notochord, sparsely 

 dotted -=■ mesoderm, white = endoderm; future somites numbered; 

 g\ boundary of the invaginated area; oe: future blastopore lip; 

 oerm.gr.: blastopore furrow; St.: tail area, z.y.'. lateral plate meso- 

 derm. After Vogt. 



