160 MAMMALIA. 
Brapypus, Lin. 
The Sloths have cylindrical molars, and sharp canini longer than 
those molars, two mammz on the breast, and fingers united by the 
skin, and only marked externally by enormous compressed and 
crooked nails, which, when at rest, are always bent towards the 
palm of the hand, or the sole of the foot. The hind feet are ob- 
liquely articulated on the leg, and rest only upon their outer edge 5 
the phalanges of the toes are articulated by a close ginglymus, and 
the first, at a certain age, become soldered to the bones of the meta- 
carpus or metatarsus, which also, in time, for want of use, expe- 
rience the same fate. To this inconvenience in the organization of 
the extremities is added another, not less great, in their proportions. 
The arm and fore-arm are much longer than the thigh and leg, 
so that when these animals walk, they are compelled to drag them-. 
selves along on their elbows. The pelvis is so large, and their 
thighs so much inclined to the sides, that they cannot approximate 
their knees. Their gait is the necessary effect of such a dispropor- 
tioned structure.(}) They live in trees, and never remove from the 
one they are on until they have stripped it of every leaf, so painful 
to them is the requisite exertion toreach another. It is even asserted 
that to avoid the trouble of a regular descent, they let themselves 
fall from a branch. The female produces but a single young one 
at a birth, which she carries on her back. 
The viscera of these animals are not less singular than the rest of 
their conformation. The stomach is divided into four sacks,*ana- 
logous to the four stomachs of the Ruminantia, but without leaflets 
or other internally salient parts, while the intestinal canal is short, 
and without a cecum. 
M. Fr. Cuvier applies the name of Acueus to those species that 
have three nails to the fore feet; they have a very short tail. 
Bradypus tridactylus, L.; Buff. XIII, v and vi. (The Ai.) A 
species in which sluggishness and all the details of the organiza- 
tion which produce it are carried to the highest degree. The 
thumb and the little toe, reduced to small rudiments, are hidden 
under the skin, and soldered to the metatarsus and meta-_ 
carpus; the clavicle, also, reduced to a rudiment, is firmly | 
> 
(1) M. Carlisle has observed that the arteries of the limbs. commence by splitting 
into an infinitude of ramifications, which afterwards unite in one trunk, from which 
the usual branches proceed. | This structure being met with in the Loris, 1 hosel 
gait is almost equally sluggish, it is possible that it may exert some influence on 
this slowness of motion. Independently of this, the Loris, the Ourang-Outang, 
the Coaita, all very slow animals, are remarkable for the length of their arms. 
