SLOTHS AND THEIR ALLIES. 



579 



tected, as in the pangolins (Fig. 501) and armadillos (Fig. 

 502), with largo thick scales. They feed on insects and de- 

 cayed animal matter, or on leaves. They are of moderate 

 size, though certain extinct forms were colossal in stature. 



The leaf-eating forms, viz., the sloths, differ from the 

 other Brut a in the very long and slender limbs, the hinder 

 pair the shorter. There are five teeth above and four below, 

 which become sharp with use, like chisels ; the stomach is 

 said to be remarkably complex. In disposition these crea- 

 tures are types of sluggishness ; they live in trees, being 

 absolutely helpless on the ground, not being capable of 

 walking on the bottom of the foot. 



Waterton says that, in climbing, the 

 ai (Bradypus tridaclylus, Figs. 499 and 

 500) uses its legs alternately ; that its 

 hair " is thick and coarse at the ex- 

 tremity and gradually tapers to the 

 root, where it becomes fine as a spider's 

 web. His fur has so much the hue of 

 the moss which grows on the branches 

 of the trees, that it is very difficult to 

 make him out when he is at rest." 



None of the Edentates now occur in 

 the United States, but formerly colos- 

 sal, sloth-like forms, with some resem- 

 'blance to the ant-eaters, ranged over 

 the Southern and Middle States as far 

 north as Pennsylvania, their bones oc- 

 curring in caves. Such was the Megatherium, a gigantic, 

 sloth-like creature, which extended from Pennsylvania to 

 the pampas of South America, and whose skeleton is over 

 five metres (18 feet) long. With it was associated the Mcy- 

 alonyx, first described by Thomas Jefferson ; it was as large 

 as a bison, as was the Mylodon. These animals walked on 

 the soles of the feet, could rise on their hind legs and partly 

 support themselves by their thick tails, pulling down large 

 trees and feeding upon the leaves and smaller branches. 



In the ant-eaters the jaws are toothless, but very long, and 

 the tongue is of great length and very extensile ; the Sub- 



Fig:. 500. Ai, or Threc- 

 tni'il Sloth, in its natural atti- 

 tude. After Wood, from 

 Waterton. 



