_T. dorso et lateribus nigro-fuscis, maculis circularibus atris; infra
niveus: corpore oblongo, haud admodum ventricoso, ubique sed parcè
muricato, rostro et caudâ exceptis: capite grandiusculo, spatio
interoculari lato, parum depresso: maxillis subæqualibus: naribus
cylindraceis, recumbentibus, aperturis duabus lateralibus: lineâ
laterali in capite tortuosissimâ: pinnâ dorsali vix anali anteriore:
pinnâ caudali æquali._
D. 8; A. 7; C. 9, &c.; P. 15.
LONG. unc. 9.
FORM.—Oblong: head rather large; the snout a little more produced than
in the last species. Moderately ventricose, and apparently capable
of a certain degree of inflation. No where perfectly smooth, except
on the snout, tail, and here and there on the flanks; nor very
rough, the prickles being minute and rather scattered, most apparent
on the back, nape, (whence they advance to quite between the eyes,)
and the middle of the abdomen. The interocular space is broad,
equalling two and a half diameters of the eye at least, and a little
hollowed out. Jaws nearly equal, the upper one perhaps a very little
in advance. Nostril in the form of a small recumbent cylinder, with
an opening at each extremity. Dorsal very little in advance of the
anal; the first ray in each of these fins very short. Caudal square.
The lateral line is very tortuous, especially about the head. It
commences at the bottom of the gill-cover, whence it ascends
vertically behind the eye towards the crown, then passes over the
eye towards the snout, descends again beneath the nostril to form a
great loop in front of the eye, almost reaching to the corners of
the mouth, whence it returns beneath the eye, and, crossing its
former course nearly at right angles, proceeds along the upper part
of the side, getting lower as it approaches beneath the dorsal, to
terminate at the caudal. There are also two short transverse lines;
one across the snout, connecting the loops; another across the nape,
connecting the two main lines after they have assumed the usual
direction.
COLOUR.—“Beneath snow white. Above dark brownish black, this colour
forming a series of broad oval rings, one within another; the outer
and largest ring includes nearly the entire surface of the back and
sides. The upper surface is, in addition, marked with round spots of
a darker shade. Pectoral and dorsal fins yellowish brown. Iris,
inner edge clouded with orange; pupil dark green-blue.”—D.—In its
present state, there is no indication of the rings noticed above.
The spots, which are small, and cover nearly the whole head, back,
and sides, appear also sparingly on the basal half of the caudal,
but not on any of the other fins.
Habitat, Galapagos Archipelago.
This species was taken by Mr. Darwin at Chatham Island, in the Galapagos
Archipelago. He observes in his notes that it makes a loud grating
noise. It is remarkable for the great tortuosity of the lateral line.
The form of the nostrils is also rather peculiar.
4. TETRODON ANGUSTICEPS. _Jen._
PLATE XXVIII.
_T. supra obscure viridis: capite oblongo, subcompresso, spatio
interoculari multum contracto: corpore infra ventricoso, ubique
lævissimo, duobus, in summo dorso, cirris cutaneis parvis adornato:
maxillis subæqualibus: naribus tubulosis, indivisis, aperturis
duâbus lateralibus: lineâ laterali in capite tortuosissimâ: pinnâ
dorsali omnino ante pinnam analem; caudali æquali._
D. 8; A. 7; C. 9; P. 15.
LONG. unc. 9. lin. 3.
FORM.—Rather more elongated than the last species; especially in
regard to the head, which is also more compressed upwards, reducing
the space between the eyes to a narrow channel, much hollowed out,
and not exceeding one diameter of the eye. Body inflatable, every
where quite smooth. Jaws nearly equal, the upper one perhaps a very
little in advance. Nostrils tubular, with two lateral apertures,
somewhat similar to those of the last species, but more elevated.
Lateral line similar, taking the same windings on the head. A little
behind the transverse line on the nape, and nearly above the
attachment of the pectoral, are two small skinny appendages: there
is also a very minute one on each side of the tail, but none
elsewhere. Dorsal wholly before the anal. Caudal square.
COLOUR.—“Above dull green: base of the pectorals and dorsal black; a
white patch beneath the pectorals.”—D.—The colours must have very
much altered from the action of the spirit, as it now appears of a
nearly uniform reddish brown, only paler beneath.
Habitat, Galapagos Archipelago.
Another apparently undescribed species of this genus, taken by Mr.
Darwin at the same place as the last. He observes in his notes that it
is inflatable.
[Illustration:
_Fish. Pl. 28._
_W. Hawkins del._
]
_1. Tetrodon angusticeps._
_1a. ____ Dorsal View._
_Nat. Size._