208 EDENTATES. 
pottos among the lemurs, and it is then that they present the most striking 
resemblance to a lichen-clad knot. They are found usually either in pairs or in 
small family parties; and are harmless and inoffensive in disposition. They are 
most active in the dusk and at night; and will then wander slowly for consider- 
able distances through the forest. Their food consists exclusively of leaves, 
young shoots, and fruits, the moisture contained in which renders drinking 
unnecessary. Their favourite food is afforded by the large-leaved and milky 
cecropia trees, which are so abundant in the South American forests; and it 
is said that they seldom desert a cecropia so long as it affords them nutriment. 
The sense of hearing in these animals seems but imperfectly developed; and 
their small, dull and reddish eyes do not appear capable of very acute vision. 
Indeed, on first observing a sloth its eyes look so devoid of brightness as to give 
the impression that the creature must be blind. But a single young is pro- 
duced at a birth. When it first comes into the world the young sloth is fully 
developed, having the body thickly clothed with hair, and the claws on the toes 
of the same proportionate length as in the adult. With these claws it clings 
fast to the long hair of its mother, clasping its arms around her neck. 
Sloths are capable of enduring deprivation from food for protracted periods, 
and they are also remarkable for the severe bodily injuries they are capable of 
sustaining, while they appear to be unaffected by doses of poison which would 
immediately prove fatal to other animals of larger size. It is related that on one 
occasion a three-toed sloth kept in captivity at Turin took no food for upwards of 
a month, and appeared none the worse at the end of its long fast. All these 
circumstances clearly point to the low organisation of these animals; it being a 
well-known fact that reptiles exhibit a far greater tenacity of life than the higher 
mammals. Indeed, as a rule, the lower we descend in the animal kingdom, the 
greater becomes the power of sustaining injury. 
THE EXxtTINcT GROUND-SLOTHS. 
Family M&GATHERIIDZ. 
No account of the Edentates would be complete without some reference to the 
gigantic ground-sloths which were formerly so abundant in South America, as it 
is by their aid alone that we are able to comprehend the relationship of the true 
sloths to the ant-eaters. The best known of these creatures is the megathere, 
which rivalled the elephant in bulk; while the mylodon and scelidothere were 
somewhat smaller forms. They may be described as possessing the skulls and 
teeth of sloths, and the back-bones, limbs, and tails of ant-eaters. The megathere 
differs from most of the others in having the crowns of the teeth square and 
divided into wedge-shaped transverse ridges, owing to the variation in the hardness 
of their constituents ; but in most cases the teeth were subcylindrical, with depressed 
centres. They agreed with the sloths in having large and complete collar-bones ; 
but, as we infer from the conformation of the lower jaw, they approximated to the 
ant-eaters in the elongation of their tongues. The majority of the ground-sloths 
were South American; but one species of megathere ranged into North America, 
while an allied genus, Megalonyx, was apparently exclusively North American. 
