594 
BULLETIN OF THE BUREAU OF FISHERIES 
orange and yellow spots, too, are much scattered, but appear to remain unchanged 
in the intensity of color. 
It has been stated that the development cannot be followed for some time after 
the early cleavage stages, owing to the opaqueness of the egg. As a result, the next 
phase in the process that is clearly evident is the appearance of a notch in the edge 
of the yolk which no doubt is occupied by the head of the newly formed embryo. This 
stage is reached in about 20 to 40 hours at a water temperature of 27° to 28° C. 
(fig. 97). 
Figure 95.— Hypleurochilus geminatus. From egg in 8-cell 
stage; about 2}4 hours after fertilization. 
Figure 98 .—Hypleurochilus geminatus. From egg in abou I 
16-cell stage; 254 hours after fertilization. 
Figure 97. — Hypleurochilus geminatus. From egg showing 
early stage of differentiation of embryo, 21 hours after 
fertilization. 
Figure 98.— Hypleurochilus geminatus. From egg with well- 
differentiated embryo; 26 hours after fertilization. 
The outline of at least the head (with large eyes) and tail, which extend beyond 
the periphery of the opaque yolk, becomes distinctly visible about 25 to 27 hours 
after fertilization at a water temperature of 27° to 28° C. It is evident now that 
the embryos are not all in the same position. Some of them lie above the yolk, 
others curve underneath it, and still others occupy positions intermediate between 
the ones mentioned (fig. 98). 
