AGAMA CA5LATICEPS.
inner toe of each foot very short, the second rather longer, the third and fourth
equal in length and much longer than the second, the outer or fifth not quite so
long as the second, all armed with short, slender, curved, and pointed claws ;
the hinder extremities rather robust towards the body, slender towards the
toes; the inner toe very short, second considerably longer, the third about
double the length of the second, the fourth considerably longer than the third,
and the outer one, measured from base to point, is rather longer than the second.
The scales of the upper and anterior portion of the head are flat, unequal as
regards size, subovate, longitudinally keeled, and on the sides of the keels
rough, from fine raised ribs or small tubercles. The canthus rostralis on each
side sharp and formed of a line of keels ; the palpebral ridges also sharp, and
consists of a row of scales projecting upwards and outwards, each overlapping
externally the scale immediately behind it. The scales immediately
in front of fbe eyes are embossed like those of the forehead, their points acute
or arched, and directed upwards, those below the eye and on the sides of the
head above the upper lip subtriangular, their points directed downwards and
backwards. Towards the eye the scales are very small; towards the upper
lip three or four rows, large, all keeled, and otherwise embossed. The small
scales are separated from the large ones by a longitudinal row of aculeated
scales, those towards the temples most prominent. The scales on the upper
and posterior part of the head are flat, irregularly shaped, and, with the exception
of three or four on the temples scarcely keeled, in other respects like
those on the forehead ; two of the keeled scales of the temples are so placed
that the keels form a longitudinal line which extends from the hinder extremity
of the prominent infra-orbital ridge to nearly the upper extremity of the
ear-opening. Scales of the upper lip, exclusive of the rostral one, and of the
lower lip, exclusive of the mental one, nine, not distinctly divided. On each
side of the neck, between the ear and the shoulder, a longitudinal cuticular
fold, and above it some small protuberances, which, like the fold, are studded
with small, conical, longitudinally ribbed scales. Scales of the back and sides
triangular, keeled, and somewhat embossed ; the majority of them are of nearly
the same size, the others are larger, project more or less, outwards, and terminate
in spinous points. Four longitudinal rows of these scales exist on the
back, two on each side of the dorsal line, a number of others are irregularly
scattered between the lines and on the sides of the body. Scales of the
tail somewhat triangular, strongly keeled, and arranged in more or less regular
rings, the keels of some of them towards base are very prominent and
prolonged; these scales form four short longitudinal rows, two of which are
AGAMA CfELATICEPS.
situated on the upper surface, and one on each side. The scales on the under
surface of the tail are arranged so that the keels form almost continuous
narrow ridges. The scales of the under surface of the head are generally
smooth, those of the under parts of the neck, and of the breast and belly,
triangular and keeled, the keels prolonged beyond the scales, forming fine
spines. Scales of the extremities triangular and strongly keeled, those of the
under and anterior surfaces smallest; on the upper and hinder surfaces some
large aculeated scales.
The only specimens of this species which I have seen were obtained towards the tropic of
Capricorn. It inhabits dry, arid situations, is very watchful, and when approached attempts
by gestures, particularly of its head, to stay the advance of the intruder, hut failing that
it takes to flight, and conceals itself as it best can. In this manner of proceeding it agrees
with other species of the genus which I have had the opportunity of observing, all of whom
employ gesticulations of the head and dilatation of the throat, apparently with the hope of
creating fear in those approaching them : whoever has observed the use a monkey makes of
its head when it is approached or closely surveyed by a stranger, will readily comprehend
the practice of the lizards referred to. The embossed condition of the scales, particularly
of those of the upper surface of the head, well shown in figure a, furnishes at once the
means of distinguishing it from the species hitherto described.