_Squamis suprà-humeralibus, rhomboideis, imbricatis; subfemoralibus
transversim hexagonis; abdominalibus in seriebus decem
longitudinalibus dispositis; caudâ, corpore cum capite plus quam
duplò longiore, squamis medio carinatis, et ad margine
subcarinatis._
Habitat, Bahia Blanca, Northern Patagonia.
DESCRIPTION.—Head very narrow, much elongated and pointed, the vertex
flattened; nostrils rather large, open, round, directed laterally,
and placed in the centre of the naso-rostral plate; superciliary
plates three in number, the central one the largest; suprahumeral
scales rhomboidal, imbricated, not broader than long, in four
series; those of the arm transversely hexagonal; the anterior
surface of the thigh, and the inferior of the leg, covered with
large hexagonal, somewhat imbricated, scales; caudal scales above
quadrate, longer than broad, with a strong medial carina, and the
lateral margins slightly raised; beneath smooth; tail very long.
Anterior extremity placed against the body, reaching rather more
than half way to the thigh; posterior extremity extending forwards
nearly to the ear.
COLOUR.—The upper surface of this beautiful species is dark brown or
blackish, with nine distinct white or yellowish longitudinal
fasciæ extending through the whole length of the neck and body;
tail with four of these lines. Under parts white.
DIMENSIONS.
Inches. Lines.
Length of the head 0 6
of the neck 0 3
of the body 1 4
of the tail 5 2
────────────────────────────────────────────
Total length 7 5
Length of anterior extremity 0 7
of posterior extremity 1 5
_Reptiles. Plate 15._
[Illustration:
_Drawn from Nature on stone by B. Waterhouse Hawkins.
C. Hullmandel Imp._
]
_1._ _Ameiva longicauda._ _Nat. Size._
_2. 2a. 2b._ _Gerrhosaurus sepiformis._ „
_3._ _Cyclodus Casuarinæ._ „
Found at Bahia Blanca by Mr. Darwin. The specimens are probably all of
them very young; hence the longitudinal lines can scarcely be considered
as permanent, as most species of the genus are beautifully lineated in
the young state. The length of the tail, with its carinated scales, the
general elegance of the form, the gracile form of the head, and the neat
and distinct arrangement of the colours, render this one of the most
beautiful species of this elegant genus.
The description of the colours given above, being from specimens which
have been long in spirits, it is necessary to state that Mr. Darwin has
the following notice respecting one of them—“On the sides two dark red
streaks; tail red.”
FAMILIA—ZONURIDÆ.
GENUS—GERRHOSAURUS. WEIGMANN.
GERRHOSAURUS SEPIFORMIS. _Bibr._