DEVELOPMENT AND LIFE HISTORY OF SOME TELEOSTS 
615 
compressed. Then, at a length of about 10 mm, they have become slender again, and 
they remain so until they are fairly large fish, ranging upward of 100 mm in length, 
when, at least regius and floridanus again become deeper, and especially more robust, 
that is, less strongly compressed. It is interesting also that contrary to most of the 
other species discussed in this paper, the hakes, at no time have spines on the pre- 
opercular margin. 
The eggs of U. chuss and their development . — The eggs were obtained by Mr. Welsh 
at Gloucester, Mass., evidently directly from ripe fish. It may be assumed that the 
eggs of all the species of Uropliycis are similar. Therefore, the descriptions and draw- 
ings of those of chuss, offered herewith, may be useful in identifying those of the other 
species when they are taken. 
The eggs are small and vary little in size. The diameter of 10 eggs ranged from 
0.72 to 0.76 mm, the average being 0.74 mm. They are clear and buoyant, and con- 
tain many (54 counted in one egg) oil globules when first spawned. During incuba- 
tion the oil globules decreased rapidly in number, until most eggs retained a single 
large one, much larger than any originally present, 6 hours after fertilization. Oc- 
Fiqure 123. — Urophycis chuss. From egg in 2-cell 
stage; 1H hours after fertilization. (From a 
camera lucida drawing by W. W. Welsh.) 
Figure 124. — Urophycis chuss. From egg with 
early embryo; 50 hours after fertilization. (From 
a camera lucida drawing by W. W. Welsh.) 
casionally, however, a few minute scattered ones, in addition to the large one, were 
retained 26 hours after feritlization. 
The first cleavage took place 1 K hours after fertilization at a temperature of about 
60° F. The number of oil globules already had decreased (fig. 123). Segmentation 
progressed rather rapidly, as the morula stage was attained about 26 hours after 
fertilization. 
The embryo was well formed 50 hours after fertilization. It extended fully half 
the distance around the periphery of the egg, and the eyes were evident. Black 
chromatophores dotted the embryo (fig. 124). During the next 24 hours, that is, 74 
hours after fertilization, no important changes took place, except that the embryo 
grew larger, and the amount of yolk was reduced. Pigmentation of the embryo re- 
mained unchanged. Some convulsive movements now were noticed (fig. 125). 
At 90 hours of incubation, with a more or less constant temperature of 60° F., 
the eggs were ready to hatch. The pigment spots on the embryo had become notably 
154979—38 8 
