160 MAMMALIA. 



Bradypus, Lin. 



The Sloths have cylindrical molars, and sharp canini longer than 

 those molars, two mammae 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 ; 

 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.(l) 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 to reach 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 caecum. 



M. Fr. Cuvier applies the name of Acheus 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. (TheAi.) 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 whicli 

 the usual brandies proceed. This structure being met with in tlie Loris, whose 

 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 thelength of their arms. 



