600 
BULLETIN OF THE BUREAU OF FISHERIES 
increased in proportionate length, remain shorter and the black on their bases is much 
less extensive. H. hentz, in the meantime, has developed a bony ridge over and in 
advance of the eye making the interorbital quite flat. This bony ridge is entirely 
missing in H. geminatus and the interorbital is strongly convex. 
Specimens 8.0 to 10 mm long . — The body is moderately elongate and rather 
strongly compressed, the depth being contained about 5.3 to 5.7 times in the length 
without the caudal fin. The head is moderately deep ; the snout tapers and is about 
three-fourths as long as the eye; and the forehead is not very steep, being rather evenly 
and fairly strongly convex. The mouth remains rather strongly oblique and terminal, 
as in smaller specimens. The tip of the lower jaw is slightly below the level of the 
middle of the eye, and the maxillary reaches only a little past the anterior margin of 
the orbit. The interobital remains strongly convex, with only slight indications of a 
bony ridge over and in advance of the eye. Very small preopercular spines are present, 
the longest scarcely exceeding the length of the pupil. The dorsal and anal fins are 
quite fully developed and a fairly accurate count of the rays can be made. The caudal 
fin has a straight to a round margin and is nearly as long as the head without the snout. 
The ventral fins remain very small in specimens 8.0 mm long, but have increased 
considerably in length in fish 10 mm long, when they are about equal to the eye. 
The pectoral fins are broad at the base, the middle rays being somewhat produced and 
about as long as the head without the snout. The ventral surface of the chest and 
abdomen usually bears a few to several dark dots, sometimes a few dark markings also 
are present on the sides of the head, and the occipital portion of the head is marked 
either with small dark dots or with somewhat larger, less well-defined dark or brownish 
spots. The pectoral fin has a few to several dark dots at the base on its inner surface, 
and the oblique dark bar behind the pectoral, prominent in smaller specimens, has 
become quite indistinct in some specimens. Small elongate dark dots situated between 
the bases of the anal rays, described in smaller specimens, have become more elongate. 
Each one bends back abruptly and reaches the ray situated immediately behind it a 
short distance above the base of that ray (fig. 107). 
The characters distinguishing the young of this species, when 5.0 to 6.0 mm 
long, from Hypsoblennius hentz of the same size, in general, also separate young 8 to 
