364 HISTORICAL PALEONTOLOGY. 



nearly thrice the thickness of the same bone in the largest 

 of existing Elephants, its circumference at its narrowest point 

 nearly equalling its total length ; the massive bones of the 

 shank (tibia and fibula) are amalgamated at their extremities; 

 the heel-bone (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 vertebras 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 the fore- 

 foot is about a yard, and the toes are armed with powerful 

 curved claws. It is known now that the Megathere, in spite 

 of its enormous weight and ponderous construction, walked, 

 like the existing Ant-eaters and Sloths, upon the outside edge 

 of the fore-feet, with the claws more or less bent inwards 

 towards the palm of the hand. As in the great majority of 

 the Edentate order, incisor and canine teeth are entirely 

 wanting, the front of the jaws being toothless. The jaws, 

 however, are furnished with five upper and four lower molar 

 teeth on each side. These grinding teeth are from seven to 

 eight inches in length, in the form of four-sided prisms, the 

 crowns of which are provided with well-marked transverse 

 ridges; and they continue to grow during the whole life of 

 the animal. There are indications that the snout was pro- 

 longed, and more or less flexible; and the tongue was prob- 

 ably prehensile. From the characters of the molar teeth it 

 is certain that the Megathere was purely herbivorous in its 

 habits ; and from the enormous size and weight of the body, 

 it is equally certain that it could not have imitated its modern 

 allies, the Sloths, in the feat of climbing, back downwards, 

 amongst the trees. It is clear, therefore, that the Megathere 

 sought its sustenance upon the ground ; and it was originally 

 supposed to have lived upon roots. By a masterly piece of 

 deductive reasoning, however, Professor Owen showed that 

 this great " Ground-Sloth " must have truly lived upon the 

 foliage of trees, like the existing Sloths but with this differ- 

 ence, that instead of climbing amongst the branches, it actually 

 uprooted the tree bodily. In this tour de force, the animal 

 sat upon its huge haunches and mighty tail, as on a tripod, 

 and then grasping the trunk with its powerful arms, either 

 wrenched it up by the roots or broke it short off above the 

 ground. Marvellous as this may seem, it can be shown that 

 every detail in the skeleton of the Megathere accords with the 



