Elongate Perciform Fishes — Gosline 
99 
away from the hard substratum on which they 
feed. The more elongate forms at least charac- 
teristically rest with the tail bent, and, when 
disturbed, retreat into holes in the rock and 
coral by means of sinuous movements of the 
body. A number of the characteristic external 
features of the southern blennies are probably 
associated with this mode of life. For example, 
the pelvic rays though reduced in number are 
stout, and are attached to a short pelvic girdle 
that is firmly wedged between the wings of the 
cleithra. The dorsal fin extends far forward, in 
the extreme case of Xiphasia to above the eye. 
There is often a pair of tentacles or a transverse 
fringe of them, e.g., Cirripectes, on the nape; 
in Tripterygion there is a low transverse fringe 
across the nape in exactly the same position as 
in Cirripectes , but it is made up of bony flaps 
extending upward from the skull. 
A few other characters of Tripterygion atri- 
ceps may be mentioned because of their bearing 
on blennioid classification. The lateral line canal 
of the lacrimal and three circumorbitals is not 
covered by bone externally (Hubbs, 1952: 48, 
50). A basisphenoid is present (Makushok, 
1958: 58). The lowermost actinost in the 
pectoral girdle is not greatly longer than deep 
(Makushok, 1958: 58; compare Fig. la of 
the present paper with Makushok’s fig. 25). 
Finally, in the caudal skeleton of Tripterygion 
(Fig. 6b) the three lower hypurals have fused 
to one another. Hypurals 4 and 5 (above the 
axis ) have also fused to one another and to the 
urostyle and uroneurals. Hypural 6 is a small 
separate ossicle (the "minimum hypural" of 
Makushok, 1958), and there are two broad 
epurals. In the northern blennies, by contrast, 
the upper or epaxial hypurals are usually, though 
not always, separate from the urostyle (Maku- 
shok, 1958: 38, and fig. 22). Also, the northern 
blennioids usually have three epurals, rather 
than the two of Tripterygion. (In 1955: fig. 
7f, I provided a sketch of the caudal skeleton 
of Istiblennius gibbifrons. I have not been able 
to relocate the specimen from which the draw- 
ing was made, but judging from specimens of 
Entomacrodus marmoratus and Istiblennius ze- 
bra, which have caudal skeletons very like 
that of Tripterygion, the figure is incorrect in 
showing a fusion of the lower hypurals and the 
epurals with the rest of the urostylar vertebra.) 
The investigation of Tripterygion reported 
on here would support, in its small way, Hubbs’ 
(1952) and Makushok’s (1958) thesis that 
the "northern” and the "southern” blennies are 
diphyletic. But whether they are diphyletic in 
the sense that the two groups have wholly dif- 
ferent origins or in the sense that they have 
diverged in two different directions from the 
same or from two closely related stocks would 
seem to remain an open question. That Trip- 
terygion has little relationship to the congrog- 
adids (cf, Smith, 1952) also seems clear. 
Among the more elongate fishes investigated, 
i.e., Crystallodytes and the ammodytoids, Crys- 
tallodytes and Arnmodytes at least are sand div- 
ers. The pointed heads, long bodies, low vertical 
fins, small or absent pelvics, modified scales, and 
peculiarities of the lateral line of the body are 
probably associated with this mode of life. The 
habits of the other two ammodytoids, Bleekeria 
and Hypoptychus, are unknown. 
That there is any phylogenetic relationship 
between Crystallodytes and the ammodytoids 
seems extremely doubtful. Crystallodytes differs 
immediately from the ammodytoids in the fol- 
lowing characters. The lower jaw is included 
and the upper appears to be nonprotrusile. The 
circumorbital series of bones is complete. The 
cleithra are very oblique with the lower ends 
far forward of the upper. The dorsal and anal 
extend far back, and there is no well-demarcated 
caudal peduncle. Both the principal and procur- 
rent fin rays are reduced in number. The lateral 
line runs low on the body posteriorly, just 
above the anal base. Finally there is a series of 
specializations related to the eye and suspen- 
sorium of Crystallodytes. In the first place, the 
eye itself is very characteristic, for Crystallo- 
dytes is a pop-eyed fish (Fig. 1 b) with the 
small pupil protruding notably beyond the rest 
of the eyeball. This eyeball is supported below 
by a large and firm subocular shelf composed of 
the greatly expanded mesopterygoid. This bone, 
together with the palatine, forms a nearly sepa- 
rate portion of the suspensorium only weakly 
attached to the rest of this structure by the long, 
weak ectopterygoid (Fig. 4c). Neither the sus- 
pensorium nor the peculiar eyeball shows any 
relationship whatever to those structures in 
