302 ORDERS OF MAMMALIA. 



animals. The former, on the other hand, though in many 

 respects similarly constructed, and likewise vegetable-feeders, 

 were of gigantic size, and must have lived exclusively upon 

 the ground. The most celebrated of these great Gravigrada 

 is the genus Megatherium, of which M. Cuvieri (fig. 611) of 

 the South American Pampas may be taken as the type. 

 This species comprised colossal Sloth -like animals, which 



Fig. 611. — Megatherium Cuvieri. Post-Pliocene, South America. 



attained a length of from twelve to eighteen feet, with bones 

 more massive than those of tlie Elephant. Thus the thigh- 

 bone is nearly thrice the thickness of the same bone in the 

 largest of existing Elephants, its circumference at its nar- 

 rowest point nearly equalling its total length ; the massive 

 bones of the shank (tibia and fibula) are amalgamated at 

 their extremities ; the calcaneum is nearly half a yard in 

 length ; the haunch-bones (ilia) are from four to five feet 

 across at their crests ; and the bodies of the vertebrie at the 

 root of the tail are from five to seven inches in diameter, 

 from which it has been computed that the circumference of 

 the tail at this part might have been from five to six feet. 

 The length of tlie fore-foot is about a yard, and the toes are 

 armed with powerful curved claws, which are not developed 

 on the fifth digit ; while the pollex is wanting in the hand, 

 and the hallux and index in the foot. It is known now that 

 the Megathere, in sjDite of its enormous weight and ponder- 



