634 
BULLETIN OF THE BUREAU OF FISHERIES 
The development of the egg of the hogchoker is quite usual for a teleost and is well 
shown by the drawings presented herewith. Therefore, extended descriptions of the 
different stages in the development are not necessary. In the series of illustrations 
prepared during our investigation the cells are all shown as of fairly uniform size 
and shape. Some eggs were observed, however, in which the cells were more or less 
unequal in size and somewhat different in shape. Figure 146, prepared by Mrs. 
Effie B. Decker under the supervision of Dr. Albert Kuntz, is introduced to show a 
rather extreme case of unsymmetrical cleavage. Too many eggs with more or less 
unequal cells were seen to permit us to consider variation an abnormality. It may be 
assumed, therefore, that the cells in the early cleavage stages are apt to vary somewhat. 
During the early cleavage stages the blastoderm appears as a rather flat mass of 
cells. However, in the more advanced cleavage stages it is very distinctly dome- 
shaped, with a cavity beneath it, as shown in a side view, in figure 147. This stage 
apparently is reached within 2 or 3 hours after fertilization. 
Figure 148. Achirus fasciatus. From egg showing an early Figure 149 . — Achirus fasciatus. Egg showing later stage in 
stage in the differentiation of the embryo (the shaded differentiation of embryo; about 12 hours after fertilization, 
streak to the right). 
The development shown in figure 148, a rather early stage in the differentiation 
of the embryonic axis (the dark streak to the right), is attained about 6 to 8 hours 
after fertilization. Many greenish granules are present within the egg. Note the 
concentration of the oil globules in figure 148 in contrast with their scattered positions 
in figure 149, as well as in some of the other illustrations. This concentration is not 
characteristic of this nor any other particular stage of development, but varies in 
individual eggs. 
The rather early embryonic stage shown in figure 149 was attained in about 13 
to 14 hours. Note that the eyes with lenses are just becoming differentiated. No 
somites are visible, probably because the embryo is too opaque. Many greenish 
specks are present on the embryo and some scattered ones on the yolk. A few more 
or less definitely formed chromatophores, too, are becoming visible. 
The moderately advanced embryonic stage shown in figure 150 was attained in 
about 26 hours. The embryo evidentally is too opaque to allow the somites to be 
seen. It is capable of considerable movement, and slow heart action may be seen. 
Green specks still are numerous, and comparatively many chromatophores are present, 
