610 
BULLETIN OF THE BUREAU OF FISHERIES 
visible in the vicinity of the head of the embryo and all poured their contents into the 
heart, which had the appearance of a pit (fig. 121). 
No important changes in the embryo itself appeared after about the seventh day 
of incubation. The temperature remained near 24.5° C. from the fifth to the ninth 
day when it advanced to 26° C. On about the ninth day it was evident that the 
black color concentrated in the abdominal region of the embryo, first noticed on the 
fifth day, was on the embryo, whereas it at first appeared to be on the yolk. On some 
eggs a few “crow’s feet” remained on the yolk, whereas in others they had all dis- 
appeared. A dark blotch was present between the anterior part of the eyes, and in 
some specimens short, branching, cross lines were evident on the ventral margin of 
some of the caudal myomeres. Also distinct black spots were present on the pectoral 
fin membranes which could be seen clearly through the egg case. The eggs in two 
unguarded nests (the writer was not successful in inducing a male of this species, to 
stay with his nest in the aquarium) all died between the fifth and ninth days of incu- 
bation, having become infested with hydroids and protozoa. Eggs removed from the 
nests while in early cleavage stages and 
placed in glass bowls, in which the water 
was changed twice daily, also nearly all 
became infested and only four hatched. 
The rest of this account is based on the few 
remaining eggs and the four larvae that 
emerged successfully. 
On the tenth day of the incubation 
period the temperature of the water advanced 
to 27° C. The embryos were very active. 
The dark color markings on the embryo, 
already evident on the ninth day or earlier, 
had become more distinct. The number 
of blood vessels had increased and the 
blood, when viewed under moderately low 
magnification, was seen pouring over the 
head and eyes in minute vessels as if in a 
sheet. Heart action was extremely rapid, 
the beats following each other in such close 
succession that they could not be enumerated 
accurately. The heart had a distinct reddish tinge, the red probably being in the blood. 
Only four eggs survived, as previously stated, and these all hatched on the eleventh 
day of incubation. The temperature dropped from 27° to 25° C. between the tenth 
and the eleventh day. The incubation period of this blenny, therefore, is around 11 
days when the temperature of the water in which the eggs are incubated ranges 
between 24.5° and 27° C., with a mean temperature around 26° C. 
No attempt was made to keep the larvae alive. After measurements and a 
sketch had been made and a description prepared they were preserved. 
Newly hatched fish .- — The newly hatched fish range in length from 3.56 to 3.78 mm. 
The yolk is small at hatching. The head and trunk are short and robust, and the tail 
is long and slender. The vent is situated far in advance of midbody length ; distance 
from snout to vent being 1.25 to 1.3 mm, from vent to tip of tail without finfold 2.1 
to 2.3 mm. The snout is short and blunt, its length being less than half the diameter 
of the eye. The eye is large, its diameter (0.36 mm) being a little greater than the 
depth of the body just behind the vent (0.32 mm). The mouth is placed rather low, 
Figure 121. — Chasmodes bosquianus. From egg with large 
embryo; about 7 days after fertilization. H, heart. Arrows 
indicate direction of flow of blood in the larger vessels. 
(Drawn by Nell Henry.) 
