_Capite squamis subæqualibus, rhomboideis, imbricatis, carinatis
tecto._
_Proctotretus pectinatus_, Bibr. Hist. Rept. IV. p. 292.
Habitat, Patagonia.
DESCRIPTION.—The scales of the head are narrow, closely imbricated,
strongly but not acutely carinated, and the anterior ones arranged
in somewhat of a radiating direction from the muzzle. There is but
a single series of scales between those of the upper lip and the
orbit, and these, together with all the scales about the head,
partake of the carinated and elongated character already
described. A single strong triangular scale and two smaller ones
are placed on the anterior margin of the ear, which is narrow,
oval and reniform. The scales of the temples and sides of the neck
are rhomboidal, acute, carinated and imbricated. There is a
longitudinal fold on each side of the neck and a transverse one
anterior to the shoulder, behind which is a deep depression. The
scales of the back and side are prominently and acutely carinated,
those of the central line being rather more prominent than the
others; and above this there is on each side a marked longitudinal
lateral crest extending from beneath the eyes to the base of the
tail. The scales constituting these crests are very prominent,
narrow and acutely carinated. The scales of the belly are also
imbricated and rhomboidal, but flat; those of the under surface of
the hands and feet are carinated; and those of the toes have three
carinæ. The body is somewhat depressed as is the tail at its
commencement, becoming more rounded and rather abruptly smaller at
some distance from its origin. The fore-foot reaches to about
two-thirds of the distance from the shoulder to the side, and the
hinder extremity thus placed extends to the shoulder.
The colours of this most elegant of all the species of the genus
are very beautiful. “This is the most beautiful lizard,” says Mr.
Darwin, “I have ever seen; the back has three rows of regular
oblong marks of a rich brown, the other scales symmetrically
coloured either ash or light brown; many of them of a bright
emerald green; beneath pearly, with semilunar spots of brilliant
orange on the throat.” I find in the specimens I have examined
that the pectinated lateral crests are white, and the brown oblong
marks of the back are bordered with a similar colour. There are
always three white transverse lines across the head.
DIMENSIONS.
Inches. Lines.
Length of the head 0 7
of the body 1 7
of the tail 3 1
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Total length 5 5
Length of anterior extremity 1 0
of posterior extremity 1 5
This species, as has been observed by M. Bibron, who first described it,
may be at once distinguished from every other by the character of the
scales of the head, which, instead of lying flat, with the edges in
contact, are all of them imbricated and carinated. Another obvious
distinguishing character, is the narrow line of prominent scales running
the whole length of the body on each side, forming a sort of
_pectinated_ lateral crest, from which circumstance it has derived its
name.
Found by Mr. Darwin, at Bahia Blanca, and Port Desire in Patagonia.