3IO 



Charles Zeleny. 



Fig. 12 (x2i6). 



Cleavage Stages of Isolated Blastomeres of the Two-Cell Stage. 



A, four-cell stage from an isolated blastomere. Note wide cross furrow; 

 also, that the blastomeres are not in one plane. B, four-cell stage. C, eight- 

 cell stage. D, eight-cell stage of plate type. E, eight-cell stage of slightly- 

 curved plate type; viewed from convex side. F, eight-cell stage of curved 

 plate type; side view. G, eight-cell stage of very shallow cup type; viewed 

 from convex side. H, eight-cell stage of shallow cup type. I, 16-32-cell stage 

 of cup shaped type (i^geometrical half of normal blastula) ; side view. 



