2ft 
SLOTH. 
SLOTH. 
( Bradypus didactylu .?.) 
The Unau, or Two-toed Sloth, is indigenous to the hot parts of America. It is clothed 
with coarse hair of a singular texture, resembling withered grass, patched with light and dark 
brown. Coarse at the extremity, it is fine as a spider’s web at the root. The dental system 
is exceedingly simple. The teeth are all molars, ten in the upper jaw, and eight in the lower, 
but with the first one on each side of either jaw so set forward from the rest as to appear like 
one of the canine series. These teeth are cylinders of bone, made up of vascular dentine 
ivory, and cement. The fore-limbs are twice as long as the hinder pair, and all four are ter 
minated by hook-like claws, which are longer than the whole sole of the foot. These claws 
are bent inwards, and can be raised only by an effort, and that only in a slight degree. The 
natural position of the Sloth is swinging, suspended by ifs claws, under the branches of trees 
It frequents particularly the Cercopia , on the buds and shoots of which it feeds. On the 
ground this animal is entirely out of its element; it can then drag itself slowly and painfully 
forward only by hitching its claws into any depression that may afford a hold. The zygomatic 
arch is bold and stout, but incomplete; the malar bone is well developed, giving oft' ascending 
and descending branches; there are no supernumerary cervical vertebrae as in the Ai. It has 
28 pairs of ribs of lizard-like character; a pelvis like that of the bird in conformation and 
character; and the thigh-bones are directed obliquely outwards. The length of the Unau is 
about two feet 
