Cuvier and Valenciennes ; but as the notice of it in the “ Histoire des Poissons”
is extremely brief, I have deemed it advisable to annex a detailed description.
Both Mr. Darwin’s specimens are from King George’s Sound, where the species
was first discovered by MM. Quoy and Gaimard.
S e e i o l a b i p i n n u l a t a . Q u a y et G a im .
Seriola bipinnulata, Quoy et Gaim. Voyage de I’Uranie (Zool.) p. 863, pi. 61. f. 3.
------------------------ Cuv. Regne An. (2d Edit.) tom. ii. p. 206.
F o rm .— Elongated, and fusiform. G reatest depth contained four times and a half in the length,
measuring this last to the base o f the caudal fork. Head four times and a quarter in the same :
depth o f the head not quite once and three-quarters in its own length ; the cheeks nearly vertical.
Snout pointed : profile straight, and but slightly falling. Lower jaw a little longer than
the upper, the commissure reaching to beneath the orifices o f the nostrils ; maxillary very conspicuous,
and greatly dilated a t its posterior extremity. A band of minute velutine teeth in each
jaw , broadest in front; a disk of similar teeth on the vomer, and a band on each palatine. Eyes
large ; their diameter one-fifth the length of the head ; situated a little above the middle of the
cheek, and a little nearer the end o f the snout than the posterior margin of the opercle; exactly
two diameters between the eye and the end of the lower jaw . The nostrils consist of two small,
round, closely approximating orifices, the anterior one partially covered by a membrane ; situated
rather nearer the eye than the extremity of the snout. Preopercle with the ascending margin
vertical, and the angle a t bottom rounded ; the limb very broad, and marked with veins, and
between the veins, along the basal margin, with fine striæ. The rest of the pieces of the gill-
cover, taken together, present a rounded and regularly curved outline posteriorly; the line of
separation between the opercle and subopercle ascends obliquely backwards from a point about
two-thirds down the posterior margin of the preopercle ; that between the subopercle and the
interoperele (which last is well developed) passes downwards and backwards, forming an angle
o f about 45'* with the axis of the body. Branchial aperture large ; the membrane deeply cleft.
Snout, jaw s, and pieces of the opercle, smooth and naked ; cheeks scaly, the scales on the
upper part of the cheek, between the eye and the upper angle of the preopercle, being of a narrow
pointed form. The scales on the body are of a moderate size, oval, m arked with fine concentric
circular striæ, with a fan of coarser diverging striæ on their concealed portion. The lateral
line is smooth throughout its length, and runs nearly straight from the upper angle of the opercle
to the caudal, its course being a little above the middle.
The first dorsal commences at about one-third of the entire length, measuring this last as
before : it is low and inconspicuous, consisting of only six weak spines, o f which the third and
fourth are somewhat the longest, b u t whose length is less than one-fifth of the depth o f the
body. The length o f the fin itself is rather less than h alf the depth. Second dorsal closely
following, and much longer ; of the form usual in this family, with the anterior portion elevated
and somewhat triangular, but beyond the ninth ray low and even : its spine h alf the length of
the first soft ray : its greatest elevation contained about two and a-half times in the depth. The
last two rays of this fin are broke away from the rest, with an intervening space, to form a spurious
finlet, and are rather longer, the last especially, than those which precede. The anal commences
opposite the fourteenth ray of the second dorsal, and is similar in form to th a t fin, but
of course shorter, and also less elevated a t its anterior extrem ity: finlet and the intervening
space exactly corresponding. Caudal deeply fork ed ; the lobes very long and pointed, each
equalling nearly one-fourth of the entire length ; the middle rays not one-fourth the length of
the lateral ones. Pectorals attached a little below the m iddle; in length a little exceeding half
that of the head. V entrals about the same size as the pectorals, but attached a little
further back. A slight elevation a t the sides of the tail, but no distinct keel, properly so
called.
D. 6—1/24—1 ; A. 1/16—1 ; C. 17, &c.; P. 20; V. 1/5.
L ength 18 inc. 3 lines.
C o l o u r .—“ B and on the side azure b lu e; above a duller greenish blue; beneath two greenish
metallic stripes: lower half of the body snow white.”— D. No trace of the longitudinal
stripes remains in the dried skin.
Habitat, Keeling Island, Indian Ocean.
A tolerably exact figure of this species occurs in the Zoological Atlas of
Freycinet’s Voyage, but I can find no notice of it in the “ Histoire des Poissons ”
of Cuvier and Valenciennes. Although referred by Cuvier in his “ Regne A nimal’’
to Seriola, it rather departs from that genus in some of its characters. Independently
of the spurious fiiilets in the dorsal and anal fins, which separate it
from all the other species, I see no trace of any reclined spine before the first
dorsal, nor of two free spines before the a n al; in both which respects Seriola is
said to resemble L ich ia . Possibly, how'ever, as Mr. Darwin’s specimen is a dried
skin, these characters may have been destroyed in the process of preparation.
And to the same cause, perhaps, is to be attributed the circumstance of my not
being able to observe more than one spine in the true anal, Quoy and Gaimard
mentioning two. On the other hand, these naturalists appear to have overlooked
the narrow pointed scales on the upper part of the cheeks, which are of a different
character from the scales on the body.
Mr. Darwin’s specimen of this species was obtained at the Keeling Islands.
T he one figured in Freycinet's Voyage was procured at Papua or New Guinea.
It probably, therefore, has a considerable range over the Indian Ocean.
P s e n e s ?
Psenes leucurus, Cuv. et Val. ? Hist, des Poiss. tom. ix. p. 197.
Mr. Darwin’s collection contains two individuals of a species of Psenes, in
reference to which his notes state that they were taken in Lat. 17° 12' S.,
Long. 36° 33' W., a hundred and twenty miles from the nearest land above water,
though shoals were considerably nearer. They do not measure more than one
inch eight lines in length ; and from their small size, and their not being in a very