l6o Edivm G. Conklin. 



Develoi'Ment of Right Blastomerl of the 2-Cell Stage; also of Right and Left Blastomeres 



OF the 4-Cell Stage. 



Figs. 19, 20. Same embryo as that shown in Figs. 13-18. Fig. 19. Right half of 46-cell stage, 

 posterior view; the yellow crescent cells are not quite normal in position. Fig. 20. Right half of 

 48-cell stage, dorsal view. The caudal endoderm cells (B''-' and B"-'-') have been shoved away from the 

 median plane by the cell B^-^. 



Figs. 21,22. Fixed and stained preparations of half embryos in the 1 6-cell stage. Fig. 21. Right 

 half embryo, posterior view. Fig. 22. Left half embryo, ventral-posterior view. 



Figs. 23, 24. Successive stages of one and the same half embryo, the left half having been injured 

 in the 4-cell stage, dorsal view. Fig. 23. Right half of i6-cell stage. Fig. 24. Right half of 32-cell 

 stage. The cleavage is like the right half of a normal egg in every respect. 



