This curious little species has been described by Weigman under the
present n am e ,-b y Tschudi under the generic name of Ckaunm, and fuliy by
Bibron, who retained the name originally given to it by Weigman. I t now
remains only to correct, from Mr. Darwin’s notes, some points respecting the
colours, which had been mis-stated in consequence of the action of the spirit in
which the specimen had been preserved. The colour of this curious miniature
representation of a Toad, is “ ink black,” excepting tlie palms and soles of the
feet, a large transverse spot across the posterior part of the abdomen, two smaller
ones near the middle, and in some specimens a few scattered little spots, all of
the most intense vermilion red. There is one specimen from Bahia Blanca which
has also some small “ buff-orange” spots on the upper part.» Mr. Darwin observes
th a t “ the appearance of the vermilion colour is as if the animal had
crawled over a newly painted b o a rd ;” and he add.s— “ This Toad inhabits the
most dry and sandy plains of Bahia Blanca, where there is no appearance of
water ever lodging.” The other specimens were taken a t Maldonado, where
It inhabits the sand-dunes near the coast. Mr. Darwin threw one into a pool of
fresh-water, but he found it could hardly swim, and he thinks, if unassisted, it
would have been soon drowned.
This species is diurnal in its habits, and may be daily seen under a scorchino-
sun, crawling over the parched and loose sand. M. D ’Orbigny brought specimens
from Monte Video.
DIMENSIONS.
In. Lio.
Length of the head and body .............................. i q
of the anterior extremities ..................... 0 5
of the posterior extremities..................... 0 8
G e n u s— UPERO D O N . Bibr.
U p e r o d o n o r n a t u m . Mihi.
P l a t e X X.—F ig . 6.
Capite multò latiore quam longiore. Dorso oliváceo, maculis fuscis, albo marginatis.
Habitat Buenos Ayres.
DESCMFTIOX.-Head more th a n h a lf as broad again as it is long, an d equa l In b re ad th to h a lf the
en tire englh o f th e head an d body. Muzzle ro u n d ed . Nostrils oval, open in g upwards and a
^ This spei
-.VO V. uruL.li oiiiyyiner SKin th a n t
Bahia Blanca has a much smoother skin th,an the others; but from its similarity in all
1 he Tin rlihi.ltf rsf Uc ... .. '
other characters there can b e no doubt of its specific identity with them.
u
little outwards. E y e s ra th e r large, th e u p p e r eyelids forming perfec t flaps, which entire ly
cover the eyes. Body rounded, very broad. T h e shoulders an d thighs wholly concealed by
th e skin o f the body. Limbs very short. T h e an te rio r fe et very broad. T h e toes somewhat
d epressed, very short, b orde red with a fold o f skin. H in d e r fe et with th e toes more depressed
and more distinc tly borde red. Back covered with small glands.
C o l o u r .— T h e colour o f th e u p p e r surface is dark olive, becoming lig h te r a t th e sides, an d having
numerous dark brown spots, which are round, oval, elliptical, o r irregular, o f very various sizes,
placed somewhat symmetrically, an d each borde red with a whitish or yellow line. Beneath
pale, exc epting the th ro a t, which is black.
I have ventured to consider this remarkable amphibian as specifically distinct
from U. marmoratuni 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 th a t species. The other was found by M. Leschenault in the interior of
the peninsula o f In d ia : 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 th a t 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.
U P E R O D O N M A R M O R A T U M .
“ L a tê te offre en arrière u n e larg e u r à peu
prè s égale à son lo n g u eu r totale, laquelle en tre
p o u r le q u a rt environ dans l’é te n d u e de l’an imal.”
“ On p o u rrait considérer la p eau comme
é ta n t parfaitement lisse, si l’on n e voyait éparses
su r le dessus d u tronc u n c e rtain nombre de
verrues glanduleuses d’un assez g ra n d diamètre
re la tiv em en t à la grosseur de l’animal, mais fort
p eu saillantes ou à peine convexes.”
“ L e s partie s supérieures de ce Batra cien
p ré se n te n t sur u n fond olivâtre, d ’énormes
tâches brunes, toutes conjîuentes, ou s’anastomosant
diversement.''*
U P E R O D O N O R N A T U M .
H e ad fully h a lf as broad again as it is long,
an d equal in b re ad th to h a lf th e total length of
th e animal.
Back covered with numerous small glandular
tubercles, notably elevated.
A ll th e spots on th e back are quite distin c t,
n o t in any way passing in to each o th e r o r conn
ec ted , and ea ch encircled by a white line.
* Bibr. Rept. Y I I I . p. 74