PLATE XXIX. Fig. 2.
FORM.—Very much elongated, subcylindric anteriorly, compressed and
ensiform behind. Greatest depth in the region of the pectorals, and
about one-tenth of the entire length. Head, measured to the extreme
point of the gill-cover, five and a half times in the same. The head
is rather larger than any part of the body, its depth and thickness
being equal, and each a trifle less than the depth of the body.
Crown and forehead a little flattened, whence the profile descends
in a curve before the eyes. Snout blunt and rounded, projecting,
both in front and at the sides, beyond the lower jaw. Gape wide, and
reaching to beneath the middle of the eye. Intermaxillary somewhat
protractile at the sides, but not in front; shorter than the
maxillary, with a considerable intervention of membrane between the
extremities of the two bones, which are not united posteriorly,
excepting by the membrane just mentioned. Maxillary long, rather
slender, of nearly uniform breadth and thickness throughout,
retiring in part beneath the suborbital, and reaching backwards to a
vertical from the posterior part of the orbit. Intermaxillary with a
single row of small, pointed, subconical, slightly curved teeth; in
front of these, and quite at the anterior extremity of the jaw, two
strong, hooked, regular canines:[52] the teeth in the row rather
wide asunder, and set a little irregularly, about thirty in number.
In the lower jaw, teeth few in number, scarcely more than eight or
ten in front, rather stronger than the intermaxillary series,
followed by a moderate canine on each side, these last smaller than
the ones above: at the sides of the lower jaw, beyond the canines,
scarcely more than one or two small teeth (possibly others are
fallen). A small cluster of three or four teeth on the fore part of
the vomer, like those in front of the lower jaw, and a row on each
palatine. Pharynx also armed with strong teeth; but the tongue,
which is free at the tip, and rounded, smooth. Eyes large and
prominent, and elevated rather above the line of the profile: their
diameter one-fourth the length of the head; their distance from the
end of the snout one diameter; the interocular space reduced to a
narrow channel, and scarcely equalling half a diameter.
Opercle of a triangular form; subopercle lanceolate, projecting
further than the opercle, and passing upwards and backwards to form
the terminating angle of the gill-cover. Gill-opening of very
moderate extent; the branchial membrane fastened down underneath,
with five rays. Skin smooth and naked, loose, and probably very
mucous in the living fish. Apparently no lateral line. The edges of
both jaws curiously fringed each with a row of tubipores, or
cutaneous appendages in the form of tubes, having pores at their
terminal extremities for the exudation of mucus. The row on the
upper jaw is continued along the margin of the suborbital on to the
cheek; that on the lower is carried upwards to form an edging to the
preopercle. There is also one of these tubipores at each nostril,
another behind each eye, and a third on each side of the nape.
The dorsal commences above the terminating angle of the gill-cover,
and extends the whole length of the body: its height nearly uniform
throughout, equalling half the depth: the rays slender; all
articulated, except the third, which is spinous, and shorter than
those which precede and follow it; mostly simple, but some of the
posterior ones slightly divided at their tips. Vent situate beneath
the termination of the first quarter of the dorsal. The anal begins
immediately behind it, and, like the dorsal, is carried on to the
end of the body, to unite with it in forming a pointed caudal; all
the rays soft and delicate. Pectorals rather pointed, with the
middle rays longest, and about two-thirds the length of the head.
Ventrals very minute and narrow, of only three rays, and appearing
like one filament, about one-third the length of the pectorals;
attached in front of the pectorals, and nearly in a line with the
gill-opening.
B. 5; D. about 80; A. about 60; C. about 15; P. 16; V. 3.
Length 5 inc. 9 lin.
COLOUR.—Not noticed in the recent state. In spirits it is nearly
colourless, with the exception of a dark bluish line along the base
of the dorsal; upper part of the head, and nape, also stained with
the same dark tint.
Habitat, Archipelago of Chiloe.
This species was taken by Mr. Darwin under stones. There is but one
specimen in the collection, and it would be very desirable to see
others, in order to ascertain whether the circumstance of the _third_
dorsal ray _alone_ being spinous, (those that precede as well as follow
being articulated), is merely accidental in the one above described, or
really characteristic of the species. If the latter, it is an anomaly,—a
single spine thus occurring in the middle of a soft fin,—of which I know
no other example.