_Squamis capitis convexis; caudâ, corpore cum capite longiore._
Habitat, Port Desire, Patagonia.
DESCRIPTION.—Head short, almost equilaterally triangular, rising
obliquely from the muzzle to the vertex, then flattened. Nostrils
large, round, each placed in front of the suprà-orbital crest, and
in a line between it and the centre of the muzzle. The ears are
small, oval, the margin simple, and the membrana tympani
superficial. The neck is considerably contracted; it has a
longitudinal fold on each side formed by the confluence of two
others, one of which arises from behind the angle of the mouth,
and the other from above the ear, which is, as it were, enclosed
between them; they coalesce a little behind the ear. There is also
a distinct transverse fold on the throat, very similar to that in
_Leiosaurus Bellii_. The body is moderately thick, somewhat
depressed, and without the slightest appearance of a longitudinal
crest, or any elevation along the median line. The tail is
somewhat longer than the head and body, nearly round and tapering
almost evenly from its origin to the apex. The fore legs are short
and moderately robust, the toes short, nearly equal; the hinder
legs moderately long. The former when placed against the sides, do
not reach the thighs by nearly a third of the distance between the
two limbs; the latter when directed forwards, just reach the
axillæ. The cloacal covering is semilunar, turgid, and the margin
quite simple.
Scales covering the upper surface of the head numerous, rounded,
and considerably elevated; those between the two suprà-orbital
semicircles are in a double series. The occipital plate is oval,
raised from the margin, hollowed immediately around the centre
which is again raised like a minute tubercle. Above the labial
scales, is a series of equal, rounded, oblong scales, and between
these and the principal suborbital is a single series of smaller
ones. Scales of the whole of the upper and lateral parts of the
neck and body extremely small, slightly elevated, passing at the
sides into a flatter and more expanded form. Those of the whole of
the under parts are quite flat and imbricated. Beneath the
anterior parts of the lower jaw, and behind the broad mental
scales, are a series of flat, hexagonal scales on each side,
passing backwards and outwards, the front pair large and oblong
and the others diminishing by degrees. The scales of the throat
are very small, those on the fold larger and acutely rhomboidal.
The scales of the anterior part of the belly are also rhomboidal
and those of the posterior portion hexagonal or nearly quadrate.
The tail is covered by scales disposed in whorls, those on the
median line beneath being larger than the others. Beneath each toe
is a series of transverse hexagonal imbricated scales.
The colours and markings of this species are very difficult to be
described, on account of the great irregularity of their
disposition. The ground colour of the head is yellow, passing into
grey on the back part. The anterior part has several small spots
of a dark brown colour, and there is a larger one on each orbit,
another between the eye and the ear, and others on the back part
of the head extending to the neck. The middle of the back is
reddish yellow, on each side bluish gray, passing beneath into
yellowish white. A series of very irregular transverse spots cross
the yellow median portion of the back, and there are others on the
sides; and these two series becoming confluent on the tail, form,
with the yellow ground, alternate half rings of the two colours.
The upper part of the legs has similar bands. The whole of the
throat, belly, and inferior surface of the limbs and tail are
yellowish white. There are numerous small blackish spots over
these parts which are more distinct and linear on the throat, and
becoming paler, smaller and round on the belly.
_Plate 10._
[Illustration:
_From Nature by B Waterhouse Hawkins:
in Lithotint, C Hullmandel’s Patent._
]
_Diplolæmus Darwinii. Nat. Size._
_Plate 11._
[Illustration:
_E. Waterhouse Hawkins del;_
_Printed by C. Hullmandel._
]
_Diplolæmus Bibronii_ _Nat. Size._
DIMENSIONS.
Inches. Lines.
Length of the head 1 0
of the body 2 2
of the tail 3 8
────────────────────────────────────────────
Total length 7 0
Length of anterior extremity 1 1
of posterior extremity 1 6
Taken at Port Desire, on the coast of Patagonia.