254 THE WORLD OF LIFE 



they were intermediate in structure between the living sloths 

 and the ant-eaters, but adapted for a different mode of life. 

 Almost all are of large, and many of gigantic size. The Mega- 

 therium, which was discovered more than a century ago, was one 

 of the largest, the skeleton (represented by a cast in the British 

 Museum) being 18 feet long. Their massive bones show enor- 

 mous strength, and they no doubt were able to uproot trees, 

 by standing erect on the huge spreading hind feet and grasping 

 the stem with their powerful arms, in order, to feed upon the 

 foliage, as shown in the illustration (Fig. 89). The jaw-bones 

 are lengthened out, indicating extended lips and probably a 

 prehensile tongue with which they could strip off the leaves. 

 An allied genus, Mylodon, which is somewhat smaller, has 

 been found also in Kentucky in beds of the same age, the 

 Pleistocene. 



What renders these creatures so interesting is that they sur- 

 vived till a very recent period, and that they were contemporary 

 with man. Both human bones and stone implements have 

 been found in such close association with the bones or skele- 

 tons of these extinct sloths that they have been long held to 

 have lived together. But a more complete proof of this was 

 obtained in 1897. In a cavern in Patagonia, in a dry powdery 

 deposit on the floor, many broken bones of a species of Mylodon 

 were found ; and also several pieces of skin of the same animal 

 showing marks of tools. Bpnes of many other extinct animals 

 were found there, as well as implements of stone and bone, 

 remains of fires, and bones of man himself. Among the other 

 animal remains were those of an extinct ancestral horse, and 

 on some of the bones there were found shrivelled remains of 

 sinews and flesh. 



Allied forms are found in older deposits, as far back as the 

 Miocene, but these are all of smaller size. They probably 

 ranged all over South America, and the two genera Megathe- 

 rium and Mylodon occur also in the most recent deposits of 

 the southern United States. The numerous skeletons in the 

 pampas of Argentina are usually found on the borders of old 



