_P. argentea, nitens, summo dorso cærulescente; operculo ad angulum
superiorem maculâ nigrâ signato; pinnis pectoralibus maculis duabus
in axillis et ad radices radiorum, minoribus._
B. 10; D. 5—1/33; A. 2—1/35; C. 17, et circa 5/5— accessar.; P. 21; V.
0.
LONG. unc. 9.
FORM.—Body very much compressed, of a rhomboidal form, the dorsal and
ventral lines rising to an angle at the commencement of the dorsal
and anal fins respectively. Head a laterally compressed cone: tail
becoming suddenly attenuated before the setting on of the caudal
fin, without any keel at the sides. Back sharp and elevated; the
greatest depth contained not more than two and a half times in the
entire length: thickness only one-fifth of the depth. The length and
depth of the head are equal, each being half the depth of the body.
The upper and under profile meet at the extremity of the snout at
nearly a right angle, the former falling in a very regular curve
from the commencement of the dorsal fin. Mouth moderately large, the
commissure reaching to beneath the eye, with the lower jaw
projecting and of considerable strength and thickness. In each jaw a
single row of very fine sharp teeth. The tongue, which is of a
triangular form, free at the tip, and pointed, is rough, with some
extremely fine closely shorn velutine teeth: a small triangular
patch of these last teeth on the front of the vomer, and a narrow
row on each palatine: pharyngeans with rather stronger teeth. The
intermaxillary is very slightly protractile. The maxillary reaches,
when the mouth is closed, to a vertical from the posterior part of
the orbit: it is very visible from without, having only its anterior
portion concealed by the suborbital, and being much dilated at its
posterior extremity, which is in shape somewhat securiform. Eyes
above the middle of the cheek, and nearer the end of the snout than
the posterior margin of the opercle; their diameter rather more than
one-fifth the length of the head: the suborbital forms a narrow band
beneath each. Nostrils half-way between the eyes and the end of the
snout; the anterior orifice round; the posterior, which is the
larger one, oval. Preopercle with the ascending margin nearly
vertical; the angle at bottom rounded. The opercle and subopercle
together present a rounded margin posteriorly, though at the upper
portion there are two small blunt points distinguishable by the
finger, between which there is a very shallow notch: the line of
separation between these two bones descends obliquely forwards to a
little above the rounded angle of the preopercle, where it meets the
line of the interopercle, which descends obliquely backwards:[26]
all the margins of the opercular pieces entire. Gill-opening very
large, the aperture reaching to beneath the anterior margin of the
eye: the membranes, each of which has as many as ten rays,[27] cross
a little over each other, and are not united to the isthmus.
[Illustration:
_Fish. Pl. 13._
_W. Hawkins del^t._
_Paropsis signata. Nat. Size._
]
Snout, jaws, and cheeks, as well as the several pieces of the
gill-cover, without scales:[28] body covered with extremely minute
ones, of an oval form, longer than broad, marked with concentric
circles, and entire on the margin. The lateral line is slightly
arched above the pectoral, and its course a little undulating, but
it descends gradually to near the middle of the body, whence it runs
straight to the caudal.
The first dorsal is represented by five short free spines, each
capable of separate motion, and each furnished with its own
membrane; in advance of them is a somewhat smaller reclined spine
with its point directed forwards: the first erect spine is above the
middle of the pectoral, and distant from the end of the snout nearly
one-third of the entire length. Beyond the five free spines, and
immediately before the commencement of the second dorsal is another
small spine closely pressed down, and almost concealed beneath the
skin, pointing backwards. The second dorsal, which has also at its
anterior edge a small spine one-third the length of the first soft
ray, commences at the middle point of the entire length, caudal
excluded. The general form of this fin is similar to that of the
genus _Lichia_, long, with the anterior portion elevated; the
greatest height about one-fourth of the depth, or hardly so much.
The anal answers exactly to the second dorsal in form and extent,
and is preceded by two free spines, separated from it by a small
space, besides a longer one at its anterior edge. Caudal forked
nearly to the base, where there are a number of minute scales; the
lobes equal, pointed, and moderately elongated, each contained about
four times and one-third in the entire length. Pectorals attached at
about the middle of the depth, a little behind the opercle; of a
somewhat triangular form, small, their length not much exceeding
half that of the head. No trace of ventrals whatever.
COLOUR.—“Uniform bright silvery, the ridge of the back bluish: a black
patch on the gill-cover, and another under the pectoral fin.”—D.—The
first of the patches alluded to by Mr. Darwin is very conspicuous,
and is situate at the upper angle of the opercle, immediately in
advance of the commencement of the lateral line. The second may be
described as consisting of two distinct spots; one at the root of
the upper rays, and completely in the axilla; the other, a small one
of an elongated form, immediately beneath the lowest ray, and partly
visible without raising the fin. The elevated portion of the second
dorsal is also dusky, and a faint edging of this colour runs for a
short way along the margin of this fin. The anal is pale.
Habitat, Northern coast of Patagonia.
I have termed this species _signata_, in reference to the black patch on
the opercle, which is a conspicuous character. The only specimen in the
collection was obtained by Mr. Darwin at Bahia Blanca, on the coast of
North Patagonia.
1. CARANX DECLIVIS. _Jen._
PLATE XIV.
_C. corpore elongato, altitudine quintam, capite quartam partem
longitudinis æquante; maxillâ inferiore longiore; lineâ laterali
infra quintum radium dorsalis secundæ subito declivi, per totam
longitudinem armatâ, laminis 82 altioribus quam longis, ubique
æqualibus; spinâ reclinatà ante pinnam dorsalem parvâ, mucrone tamen
nudato; pectoralibus ultra pinnulam analem, et prope ad analem
ipsam, pertingentibus._
B. 7; D. 8—1/35; A. 2—1/30; C. 17, &c.; P.21; V. 1/5.
LONG. unc. 7. lin. 10.
FORM.—Rather more elongated than the _C. trachurus_ of the British
seas. Greatest depth one-fifth of the entire length: head one-fourth
of the same: thickness about half the depth. Diameter of the eyes a
little less than one-third the length of the head. Lateral line
bending downwards more suddenly, and at a more backward point than
in that species. The bend commences in a line with the fifth ray of
the second dorsal, and is entirely comprised within a space equal to
that occupied by four fin-rays,[29] so that opposite the ninth ray
it again advances in a horizontal line. The posterior portion about
equals in length the anterior, the bend being included in this last.
The laminæ which protect the lateral line, and which extend
throughout its whole length, are well developed, and everywhere of
the same breadth; this breadth equalling nearly, but not quite,
one-third the depth of the body. In number they are eighty-one or
eighty-two; of which the last thirty-eight or forty, forming the
posterior portion of the line, have keels terminating backwards in
sharp spines: these spines are at first small and inconspicuous, but
gradually increase in size as they advance towards the thinnest part
of the tail, where they are sharpest and most developed.
In most of its other characters this species so closely resembles the
_C. trachurus_, as to render a detailed description unnecessary. The
reclined spine before the first dorsal, however, is smaller, though
the point is sharp and exposed: also the number of rays in the
second dorsal and anal is greater by five in each fin. The length of
the second dorsal is two and a half times that of the first. The
pectorals are long, narrow, and pointed; a little shorter than the
head, or rather less than one-fourth of the entire length; when laid
back, they reach beyond the anal finlet, and very nearly to the
commencement of the true anal itself.
COLOUR.—Not noticed in the recent state. So far as can be judged from
a specimen in spirits, the colours appear to have been similar to
those of the _C. trachurus_; and there is the same black spot on the
upper part of the opercle.
[Illustration:
_Fish. Pl. 14._
_W. Hawkins del^t._
_Caranx declivis. Nat. Size._
]
[Illustration:
_Fish. Pl. 15._
_W. Hawkins del^t._
_Caranx torvus. Nat. Size._
]
Habitat, King George’s Sound, New Holland.
Cuvier and Valenciennes have noticed several variations of form
occurring in different specimens of the _C. trachurus_, from different
seas, which they have not ventured to raise to the rank of species. That
the one here described is entitled, however, to this distinction, I can
hardly entertain a doubt. The suddenness of the bend in the lateral
line, and the more backward point at which the bend commences; the
larger number of laminæ which protect it; and also the larger number of
rays in the second dorsal and anal; all seem to indicate a specific
difference. Whether it be identical with any of the varieties noticed by
them is uncertain; but it seems to be distinct from the only one they
speak of as having been received from New Holland, in which the number
of laminæ did not exceed seventy-three. I have called it _declivis_, in
reference to the character of the lateral line above alluded to. It was
obtained by Mr. Darwin in Princess Royal Harbour, in King George’s
Sound.