FISHES AND THEIR DEVELOPMENT. 



neighboring position, as in figure 55, at a, b, or c, budding out directly from 

 the yolk. In such cases the important question remains whether the nuclei 

 which pass into the blastomeres are derived from segmentation nuclei or from 



53 



%*&%$?'$&*. 



55 



.SSSa^. 



-\ c 



J .- -"55, -gffi;^^?SB^ 



Figs. 53-56. Sections of late segmentation or early blastula stage (corresponding to PI. IV, fig. 27). The first section traverses the 

 mid-region of the segmented area, the others progress marginalward. x, Blastomeres which have recently budded out of the yolk ; 

 y, wall of sub-germinal yolk ; z, cleavage line passing deep into the sub-germinal yolk ; *. vacuoles which come to the surface of the 

 germ and form intercellular spaces. X 35. 



sperm-nuclei. In the latter event, judging by analogy, they would show amitoses 

 only; in the former they should multiply by mitosis. Examined in this light it 

 is found that the nuclei which here pass into the blastomeres show amitoses, and 



