_Squamis capitis neque imbricatis nec carinatis; supralabialibus in
serie unicâ; aurium margine anteriore granuloso; interdum
unidentata; squamis, dorsalibus carinatis, posticè acuminatis,
femorum facie posteriore præcipuè granulosâ, sed portione parvâ,
caudam versus, squamis parvis, rotundatis imbicratis tectâ._
Habitat, Port Desire in Patagonia.
DESCRIPTION.—General form robust and full; the head short, thick, and
passing into the neck without any distinct contraction; the muzzle
rounded. Scales of the head larger in proportion than in _Pr.
Fitzingerii_. Ear large, oval, with the anterior margin granular,
sometimes slightly toothed. Scales of the temples of moderate
size, imbricated, smooth, somewhat raised. A single range of oval
moderate-sized scales between the labial and the orbital scales on
the sides of the neck, above and behind the shoulder small,
granular, and some of them having a minute pore. Scales of the
back of moderate size, larger than in _Fitzingerii_, rhomboid,
having a rather prominent carina, and terminating in a distinct
point. Scales of the under parts smooth and rhomboidal. The
posterior surface of the thighs is for the most part granular, but
a small portion near the groin is covered with larger imbricated
scales; to a much smaller extent, however, than in _Fitzingerii_,
and other species which possess this character.
The general colour of the upper part of this species is a rich
dark brown, with whitish transverse bands and spots, having a
black margin. I have figured in fig. 2, of Plate VI., a remarkable
variety in which the bands are alternate black and white, and a
broader and a narrower longitudinal fascia of a yellowish-white
colour, run the whole length of the body on each side. The under
parts are yellowish-white, with dark or almost black spots; under
the throat bluish-gray with white spots.
DIMENSIONS.
Inches. Lines.
Length of the head 0 8
of the body 2 3
of the tail 3 4
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Total length 6 5
Length of anterior extremity 1 1
of posterior extremity 1 4
This species much resembles _Pr. Fitzingerii_ in many of its characters,
as well as in its size. It may, however, be at once distinguished from
it by the character of the scales of the back, which in this species are
very distinctly carinated, of a rather elongated form, and pointed at
the extremity; whereas in the other they are shorter, smaller, the
carina is very slight, almost indistinct, and the posterior extremity is
obtuse.
The tail in the larger figure of our plate is deformed, having been
renewed. The specimen figured at (2,) in the same plate, is so
remarkably distinct in the colours and marking, as to lead me to suppose
that it may possibly be a different species.