70 



GENERAL SKETCH OF 



cap into a number of cells, each containing its nucleus and 

 enveloped in its cell-membrane (Figs. 19 and 20, surface and 



9. P.M. 



9.10 



9.30 



9.40 



2 c d, e 



FIG. 18. Egg of Whiting, a. View of segmenting blastoderm, 9 p.m. b. View 

 of segmenting blastoderm, 9.10p.m. c. View of segmenting blasto- 



derm, 9.25 p.m. d. View of segmenting blastoderm, 9.30 p.m. 



e. View of segmenting blastoderm, 9.40 p.m. E. E. P. 



lateral views). Moreover, surrounding the disc, which in lateral 

 view soon becomes lenticular or lens-shaped (Fig. 20), is a ring 

 of small pinkish dots or nuclei, in the protoplasmic belt or 



FIG. 19. Egg of Cod. View of 

 many-celled blastoderm from 

 above. E. E. P. 



FIG. 20. The same. Egg of Cod. 

 View of blastoderm from the 

 side. E. E. P. 



periblast, forming the so-called nuclear zone. This is more 

 clearly seen in the highly magnified portion of the edge of the 

 disc in Fig. 20 a. The nuclei have a central speck or nucleolus. 

 IQth April, 2nd day. Next day it was found that at 

 9.30 a.m. the disc of the egg presented little change, except 

 that the nuclei in the zone surrounding it were more numerous. 

 This nuclear zone became less distinct at noon and about 1 p.m. 

 it had all but disappeared. 



