_Cristâ dorsali elevatâ; caudâ sub-compressâ; squamis ventralibus
rhomboideis, lævibus; margine anteriore meatus auditorii
quadridentato; squamâ occipitali magnâ._
Habitat, Galapagos Archipelago.
DESCRIPTION.—Head, viewed from above, forming a nearly equilateral
triangle, covered with irregular slightly raised scales.
Supra-orbital ridge prominent, and covered with a series of
elongated and imbricated scales. Occipital plate large,
pentagonal, notched at its posterior margin. The anterior margin
of the auditory passage is strongly quadridentate, from the
existence of four long and rather narrow scales. Scales of the
temple obtusely carinated, not imbricated; those of the back
strongly and acutely carinated and disposed in numerous rows,
converging backwards towards the dorsal crest. Ventral scales
rhomboidal, not carinated. Dorsal crest elevated, composed of flat
vertical scales, so closely placed as to constitute an almost
continuous line, extending from the neck to the end of the tail.
Tail somewhat compressed at the base, becoming nearly round
towards the middle. Scales beneath the feet and toes carinated.
COLOUR.—The colour of this species is thus stated in Mr. Darwin’s
notes:—“Upper part clove brown, passing into black brown with
black spots. Sides slightly tinted with orange; some of the scales
of the crest near the head are white; belly nearly white; the
whole of the throat before the fore legs glossy black. This is the
most common variety in the Archipelago. The black spots are not
unfrequently placed in waved transverse bars, and are sometimes
arranged longitudinally.”
DIMENSIONS.
Inches. Lines.
Length of the head 0 9
of the body 2 8
of the tail 5 8
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Total length 9 5
Of this species, one of the most beautiful in the whole order of
Saurians, Mr. Darwin obtained numerous specimens, one only of which is
fully adult. In the younger individuals the dorsal crest is low and
almost inconspicuous. It differs very materially from either of the two
species previously described, and I have dedicated it to Mr. Gray, who
first distinguished the genus. Mons. Bibron, unaware that Mr. Gray had
already constituted the genus under the name _Leiocephalus_, named it
_Holotropis_. I have, however, retained the former name, as having the
claim of priority.
_Reptiles. Plate 13._
[Illustration:
_Drawn from Nature on stone by B. Waterhouse Hawkins._
_Printed by C. Hullmandel._
]
_1. Gymnodactylus Gaudichaudii._
_2. Naultinus Grayii._
It constitutes one of the numerous interesting novelties obtained by Mr.
Darwin in the Galapagos. The specimens, which are of various ages, were
taken in Chatham Island and in Charles Island.