DEVELOPMENT AND LIFE HISTORY OF SOME TELEOSTS 
599 
outlines of the head. Fin rays are only partly developed in the dorsal and anal fins, 
but much better in the caudal fin which has a round outline. Ventral fins are not 
evident and the pectoral fins are short and broad, and scarcely longer than the eye. 
Several more or less distinct dark dots are present on the ventral surface of the chest 
and abdomen, and on the head and nape; an obscure dark bar crosses the forehead 
between the eyes. An oblique black bar extends from the axile of the pectoral nearly 
to the vent; and the inner surface, only, of the base of the pectoral is black. A row 
of small black dots begins a short distance behind the vent and extends to the base of 
the caudal fin (fig. 105). 
Specimens of this species at this size differ from those of the same size of Hypso- 
blennius hentz principally in the longer and more pointed snout, more strongly oblique, 
terminal mouth, in the much shorter pectoral fins, which are black at the base on the 
inner surface only, and in the somewhat more anterior position of the vent, the caudal 
portion of the body being longer than the head and trunk. 
Specimens 5.0 to 6.0 mm long. — The body is moderately deep and rather strongly 
compressed, having made no pronounced change in shape since a length of 4.0 mm was 
attained. The snout is slightly more rounded than in smaller specimens and usually 
only a little shorter than the eye. The interorbital is strongly convex and somewhat 
narrower than the eye. The mouth is terminal and the tip of the lower jaw is on or 
somewhat below the level of the center of the eye. The preopercle in some specimens 
shows indications of minute spines, but it appears to be smooth in others. Advance- 
ment in the development of rays in the dorsal and anal fins, since a length of 4.0 mm 
was attained, is not pronounced and a definite enumeration of the rays cannot be 
made. The caudal fin, however, has grown proportionate!} 7 longer, is broadly rounded, 
and similar to the adult. Very minute ventrals are evident in only a few of the rather 
numerous specimens of this size examined. The pectorals have increased in propor- 
tionate length and frequently are about as long as the eye and snout. The black, 
confined to the inner base of the pectoral fin in smaller specimens, now extends some- 
what on the lower rays of the fin, and the prominent oblique dark bar originating in 
the axile remains as described in smaller specimens. The ventral surface of the chest 
and abdomen usually bears several indefinite dark spots; the sides of the head generally 
have a few very small dark points; and the occipital surface of the head and nape has 
several more definite ones. A row of somewhat obliquely elongate dark spots begins 
a short distance behind the vent and extends to the base of the caudal fin, It is evi- 
dent now that the spots are situated between the bases of the anal rays (fig. 106). 
The principal characters distinguishing this species from Hypsoblennius hentz at 
this size do not differ greatly from the ones mentioned for specimens 4.0 to 4.5 mm in 
length. The snout in H. geminatus remains longer, although scarcely as pointed; 
the mouth is terminal and more strongly oblique; the pectoral fins, although they have 
154979—38 7 
