S. globiceps, _Cuv. et Val._ Hist. des Poiss. tom. xiv. p. 179.
FORM.—Oblong-oval, very much compressed throughout: the dorsal and
ventral lines nearly of equal curvature. Greatest depth contained
about three times and one-third in the entire length: thickness
twice and three-fifths in the depth. Head one-fourth of the entire
length, rather elevated at the nape, the forehead convex, whence the
profile descends nearly in the arc of a circle, giving the snout a
blunt and rounded appearance. The height of the head, taken in a
vertical line through the eyes, equals nearly but not quite its own
length. Mouth small, the gape not reaching half-way to the eye. Jaws
very slightly crenated on their cutting edges, the true teeth
appearing on the outer surface like minute scales. At the posterior
angle of each jaw, and on each side, are two sharp canines
projecting horizontally from the corners of the mouth, eight in all.
Eyes rather small, their diameter contained six and a half times in
the length of the head, situate a little above the middle of the
cheek, and a trifle nearer the extremity of the snout than the
posterior margin of the opercle. The nostrils consist of two minute
orifices a little in advance of the eye, and a little distant from
each other, the posterior one largest and kidney-shaped, the
anterior round and nearly closed by its membranous border. A cluster
of minute pores above and behind the eyes, and a few others
scattered about the snout.
Scales on the body very large, increasing in size at the base of the
caudal, where there are three very large ones covering the rays of
that fin for half their length or more: twenty-three in a
longitudinal line, and nine in the depth. Each scale of a roundish
form anteriorly, the basal portion with a projecting lobe in the
middle of the hinder margin, and with thirty-one striæ in the fan;
the exposed portion finely striated and granulated, with a broad
membranaceous border: those on the caudal nearly three times as
long as broad, but the ordinary ones with the length and breadth
nearly equal. Lateral line interrupted; the upper portion running
nearly straight at about one-fourth of the depth, till opposite
the end of the dorsal, where it inclines downwards: tubal pores
very distinctly ramified.
Dorsal very low, its height, in the middle of its length, being
scarcely more than one-eighth of the depth: the soft rays slightly
higher than the spinous, and increasing in length backwards. Anal
answering to the last half of the dorsal, and terminating in the
same line: three spines at its commencement not stouter than the
soft rays, the first very small. The last soft ray in both dorsal
and anal double. Caudal with the points about one-fourth of the
rest of its length; when spread, the interval is rectilineal, but
when the rays are closed the whole appears crescent-shaped.
Pectorals a little shorter than the head, of a somewhat triangular
form, the rays gradually decreasing in length from the uppermost
to the lowermost. Ventrals pointed, about two-thirds the length of
the pectorals, and immediately beneath them. A large oblong
lanceolate scale between the ventrals, nearly half their length:
also an oblong scale in the axilla of each, equalling the last of
the soft rays.
D. 9/10; A. 3/9; C. 13, &c.; P. 13; V. 1/5.
Length 11 inches.
COLOUR.—Not noticed in the recent state. In spirits, it appears bluish
grey on the back and sides with small round whitish spots, the
margin of each scale being defined by a purplish line; paler on the
belly: a white transverse line in front of the eyes passing from one
to the other; anterior part of the snout, mouth, cheeks, and lower
part of the head, yellowish white. Dorsal and anal pale, the former
with three narrow longitudinal purplish lines, the latter with one.
A portion of the under surface of the pectorals, extending from the
third to the fifth ray, and forming a longitudinal fascia, purple;
the rest of those fins, as well as the caudal and ventrals, pale or
nearly colourless.
Habitat, Tahiti.
This species was taken by Mr. Darwin at Tahiti. It so nearly answers to
the description of the _S. globiceps_ of Valenciennes, brought by MM.
Garnot and Lesson from the same locality, that I cannot suppose it to be
distinct. This specimen, however, appears to have more spinous teeth at
the corners of the mouth.