P. operculo spinis tribus, intermediâ maximâ; preoperculo margine
adscendenti denticulato; ad angulum dente unico, et ad marginem
basalem dentibus duobus, fortibus; pinnâ dorsali spinis quartâ et
quintâ longissimis; pectoralibus radiorum apicibus e membranâ paulo
exeuntibus; caudali leviter rotundatâ.
B. 7; D. 13/15 vel 16; A. 3/8 vel 9; C. 172/2; P. 17; V. 1/5.
LONG. unc. 15.
FORM.—Greatest depth about one-third of the entire length, excluding
caudal. Head rather exceeding one-third. Profile descending
obliquely in nearly a straight line from the commencement of the
dorsal to the end of the snout. Eyes large, high in the cheeks;
their diameter nearly one-fourth of the length of the head. The
lower jaw a little the longest: both it and the maxillary without
scales. A band of velutine teeth in each jaw; the outer row in card,
with some, stronger than the others, which may be considered
canines: above, the principal canines are about six in number on
each side near the extremity; below, there are three or four larger
than the others similarly situated. The preopercle has the ascending
margin distinctly denticulated; on the basal margin are two strong
teeth directed forwards, and a third at the angle. The opercle has
three strong flattened spines; the middle one most developed. At the
lower angle of the subopercle is a small flat moderately sharp
point. Fourth and fifth dorsal spines longest; the succeeding ones
gradually diminishing to half the height of the soft portion of the
fin which follows. Second anal spine very stout. Pectorals with the
tips of the rays slightly projecting beyond the membrane, giving it
a festooned appearance. Caudal slightly rounded.
COLOUR.—The specimen above described appears, in its present state,
greyish brown, with zig-zag lines in different directions of a
darker tint. A second individual is stated by Mr. Darwin to have
been, when alive, “above salmon-coloured.” A third is described as
“above aureous-coppery, with wave-like lines of dark brown, which
often collect into four or five transverse bands; fins lead-colour;
beneath obscure; pupil dark blue.” Both these last specimens appear
now, like the first, greyish brown. The wave-like lines extend over
a portion of the dorsal and anal fins.
Habitat, coast of Northern Patagonia, and the mouth of the Plata.
This species is evidently very closely allied to the _P. Brasilianum_ of
Cuvier and Valenciennes, and possibly may not be distinct. It differs,
however, in having only two, instead of three, teeth on the basal margin
of the preopercle, which character prevails in all the specimens. It has
also one or two more soft rays in the anal. It likewise approaches the
_P. aculeatum_ of the same authors, but this last species is said to be
particularly characterized by three very sharp points on the subopercle
towards the lower angle, in the room of which, in the species here
described, there is only one small triangular flattened point, rather
sharp in two individuals, but in the third blunt, with the margin
slightly crenated. The colours too appear to be different.
Mr. Darwin’s collection contains three specimens, which do not
materially differ from each other. The largest, measuring fifteen inches
in length, was taken in forty fathoms water off the mouth of the Rio
Plata. The two others, smaller, and not exceeding nine, and seven and a
half inches respectively, were got on the coast of Patagonia in lat. 38°
20′: where it is stated that great numbers were obtained, many exceeding
a foot in length. In these smaller specimens the canines are not so
numerous or well developed as in the larger one.
“One specimen when caught, vomited up small fish and a _Pilumnus_. Was
tough for eating, but good.”—D.