PLATE XIX. Fig. 2.
_G. nigro-griseus, lineis circiter decem longitudinalibus nigris:
capite lato, subdepresso; genis inflatis: maxillis æqualibus:
dentibus velutinis, externis fortioribus aculeiformibus; caninis
nullis: oculis amplis, intervallo vix plus quam semidiametrum
æquante: pinnis dorsalibus contiguis, altitudine subæqualibus;
pectoralibus radiis supernis setaceis, liberis; caudali rotundatâ:
squamis mediocribus, levissimè ciliatis._
B. 5; D. 6—1/9; A. 1/8; C. 13, &c.; P. 7 et 16; V. 1/5.
LONG. unc. 4. lin. 8.
FORM.—Head large, sub-depressed, and much inflated about the gills:
body compressed towards the tail. Depth at the pectorals contained
about five and a half times in the length: thickness at the same
point about three-fourths of the depth. Head about four and a half
times in the length; its breadth nearly equal to its own length.
Profile nearly horizontal. Eyes moderately large, with a diameter
nearly one-fourth that of the head: the intermediate space a little
hollowed out, and scarcely more than half a diameter in breadth.
Some appearance of a shallow groove on the nape reaching to the
first dorsal. Gape reaching to beneath the anterior angle of the
eye. Jaws equal: each with a broad band of velutine teeth, the outer
row stronger than the others, and slightly hooked; of these stronger
ones there are twenty-six in the upper jaw; below they are fewer,
smaller, and more irregular: no canines: no vomerine or palatine
teeth.
Pectorals about one-fifth of the entire length, oval; the first six
or seven rays nearly free to their base, and setaceous, like those
of _G. niger_; the sixteen that follow connected by membrane as
usual, and much branched. Ventrals united in the usual manner, and
a little shorter than the pectorals. The first dorsal commencing a
very little behind the point of attachment of the pectorals, and
reaching to the extremity of those fins when laid back: the
anterior spines rather exceeding in length half the depth of the
body; the last three gradually decreasing, with the membrane
terminating at the foot of the second dorsal. This last fin with
the first ray simple, and of the same height with the anterior
rays of the first dorsal; those which follow, to the number of
nine, nearly of the same height, and branched; from the root of
the ninth springs a simple ray which might be reckoned as
distinct, and if so, the entire number would be ten. Anal
commencing a little more backward, and terminating a little sooner
than the second dorsal, to which in other respects it answers; the
last ray double as before: both these fins terminate in a point
behind. Space between the anal and the caudal rather more than
one-fifth of the entire length, and equalling twice the depth
immediately beneath. Caudal rounded, about one-sixth of the entire
length; the division between the principal and accessory rays
(which last are numerous, especially above), not well marked; the
former much branched. The usual papilla behind the vent.
No visible lateral line. Scales rather large; about thirty-seven in
a longitudinal line, and eleven in a vertical; ciliated, the
concealed portion of each scale with an irregular fan of very
numerous striæ, amounting to twenty-five or more. Skin of the
suborbital marked with four longitudinal lines of salient dots,
the third from the top forking posteriorly into two: a similar
line at the upper part of the opercle at the boundary of the
scales, whence another passes vertically across the branchial
membrane; behind this is a third shorter one, taking an oblique
direction backwards.
COLOUR.—(_In spirits._) Dusky grey, with about ten, rather indistinct
longitudinal dark lines on the body, extending from the pectorals to
the caudal. Fins dusky, with some indication of small irregular
whitish spots scattered here and there. A dark spot on the upper
half of the eye.
Habitat, Galapagos Archipelago.
This is undoubtedly a new species. It belongs to the same section as the
_G. niger_ of the European seas, which in form it very much resembles,
especially in its large inflated head, and in having the uppermost rays
of the pectorals free and setaceous. It differs, however, in having
fewer rays in the dorsal and anal fins, and consequently a larger
interval between the anal and the caudal; also, in the number and
arrangement of the dotted lines on the cheeks. The colours are likewise
different; and, in the living fish, in which they were not noticed,
probably the dark longitudinal lines, alluded to in the description
above, are much more conspicuous than they are at present.
This species was taken by Mr. Darwin off Chatham Island, in the
Galapagos Archipelago.