_Capite multò latiore quam longiore. Dorso olivaceo, maculis fuscis,
albo marginatis_.
Habitat Buenos Ayres.
DESCRIPTION.—Head more than half as broad again as it is long, and
equal in breadth to half the entire length of the head and body.
Muzzle rounded. Nostrils oval, opening upwards and a little
outwards. Eyes rather large, the upper eyelids forming perfect
flaps, which entirely cover the eyes. Body rounded, very broad.
The shoulders and thighs wholly concealed by the skin of the body.
Limbs very short. The anterior feet very broad. The toes somewhat
depressed, very short, bordered with a fold of skin. Hinder feet
with the toes more depressed and more distinctly bordered. Back
covered with small glands.
COLOUR.—The colour of the upper surface is dark olive, becoming
lighter at the sides, and having numerous dark brown spots, which
are round, oval, elliptical, or irregular, of very various sizes,
placed somewhat symmetrically, and each bordered with a whitish or
yellow line. Beneath pale, excepting the throat, which is black.
I have ventured to consider this remarkable amphibian as specifically
distinct from _U. marmoratum_ of Bibron; a conclusion to which I have
been almost imperatively led, by the fact of its inhabiting a different
hemisphere from all known specimens of that species. The other was found
by M. Leschenault in the interior of the peninsula of India: the
specimen from which the present description is taken was obtained by Mr.
Darwin at Buenos Ayres. Notwithstanding the similarity of the two
species, which is so great as to have led Mons. Bibron to consider them
as identical, I could not assent to such an anomaly as the existence of
an animal, at once so rare and possessed of such limited powers of
locomotion, in two regions so widely remote. I have not the opportunity
of comparing the specimens of the former species with the present, but,
even from Mons. Bibron’s description, I believe that I can discover
sufficient discrepancies between the animals, to bear me out in the view
I have taken. These discrepancies I venture to place in the following
tabular view, and leave zoologists to form their own conclusions.