DEVELOPMENT AND LIFE HISTORY OF SOME TELEOSTS 
611 
anteriorly scarcely above tlie lower margin of the eye. The gape reaches to or a 
little behind the vertical from the anterior margin of eye. The vertical finfold is 
rather broad; originating above the auditory vesicle, it is continuous and extends to 
the vent. Large pectoral fin membranes, somewhat longer than the diameter of the 
eye, are also present. The body is fairly transparent. As a consequence, the outline 
of the brain and the circulation of the blood can be seen rather clearly. The aorta 
and the caudal vein remain rather close together, as in the embryo, both being located 
ventrally in the long tail. About 8 or 9 partly indefinitely outlined myomeres may be 
counted in advance of the vent and from 28 to 30 behind it. The vertebra count in 
two adults examined was 9 + 24 and 10 + 23. These counts seem to indicate that the 
total number of myomeres in the newly hatched fish is greater than the number of 
vertebrae in the adult. Since the demarcations between the myomeres both ante- 
riorly and posteriorly are indistinct, it is barely possible that the count is excessive. 
Nearly all the color markings on the newly hatched fish already were evident on 
the embryo several days before hatching. The black on the snout is in elongate 
“twin” blotches, situated over the anterior part of and somewhat in advance of the 
eye. The abdomen is largely black along its upper margin, the black reaching from 
the upper edge of the base of the pectoral to the vent. A few small black chromato- 
phores remain on the ventral surface of the abdomen (yolksac). The tail has short 
branching cross lines on the ventral edge, which sometimes are wanting anteriorly 
and also posteriorly. The basal three-fourths of the inner surface of the pectoral 
has black cliromatophores, the lowermost spot being very large, while those more 
distant from the base of the fin are smaller (fig. 122). 
Figure 122 . — Chasmodes bosquianus. From a newly hatched fish, 3.6 mm long. AV, auditory vesicle. Arrows indicate position 
and direction of the flow of blood in the aorta and caudal vein. (Drawn by Nell Uenry.) 
Chasmodes bosquianus is about 3.6 mm long at hatching, whereas Hypsoblennius hentz 
is about 2.7 mm long, and Hypleurochilus geminatus is only about 2.4 mm. Chasmodes 
apparently has a larger number of myomeres behind the vent, having about 28 to 30, 
whereas the other species have only about 23 or 24 at hatching. No black color 
markings were noticed under the auditory vesicle in Chasmodes, whereas more or less 
black is present in the other species. Chasmodes and Hypsoblennius agree in having 
most of the inner surface of the pectoral fin membrane dotted with black chromato- 
phores, whereas Hypleurochilus at most has only a few black dots on the base of that 
fin. On the other hand, Chasmodes and Hypleurochilus agree in having a concen- 
tration of black points, forming almost solid black, along the upper margin of the 
abdomen, extending from above the base of the pectoral to the vent, while Hypsoblen- 
nius more usually has scattered branching chromatophores quite generally distributed 
over the abdomen.' Considerable variation in the distribution of the black markings 
on the abdomen, however, has been noticed in all three species. 
