164 MOSTLY MAMMALS 



during life with huge claws, while the outermost was small 

 and clawless. That during life the creature rested on the 

 outer side of this fifth claw and the backs of the three 

 large toes, in ant-eater fashion, may, from the structure 

 and arrangement of their bones, be considered certain. 

 Unlike the ant-eater, in which it rests upon the sole, the 

 hind-foot of the Pleistocene ground-sloths is even more 

 strangely modified than the front one, these creatures 

 walking only on its outer edge, while the enormous 

 middle toe, with its gigantic claw, does not appear to 

 have touched the ground in walking, and was thus 

 always kept sharp. The first toe is wanting, and the 

 second rudimentary, while the two outer ones were rela- 

 tively small and unprovided with claws. Some idea of 

 the gigantic proportions of the megalothere may be 

 gathered from the circumstance that its hind-foot measures 

 nearly a yard in length. Of the pigmy ground-sloths of 

 Patagonia the complete skeleton has not yet been de- 

 scribed ; but so far as my recollection of a specimen in 

 the La Plata museum goes, I believe that it was not of 

 the extremely specialised type characterising the later 

 gigantic forms. Moreover, while in the latter the terminal 

 joints of the feet were neither grooved nor split at the 

 extremities, in the small Patagonian species these were 

 deeply cleft at the end, as in the scaly ant-eaters or 

 pangolins of India and Africa. As regards the structure 

 of the vertebral column, the ground-sloths exhibit certain 

 peculiarities distinctive of the ant-eaters, which are only 

 rudimentary in the sloths. 



When to this brief survey of the chief structural 

 peculiarities of the skeleton of the creatures under considera- 

 tion is added the circumstance that, from their enormous 

 size, they must necessarily have been terrestrial in their 



