Fossil Bones of the Megalonyx. 171 



than the former, and with proportions more like the latter of 

 these animals. 



The osteology of the fore-foot presents a combination of 

 characters drawn from the sloths, ant-eaters, and some species 

 of Armadillo, particularly the twelve-banded and the giant Ar- 

 madillo ; though Cuvier considers it to have resembled one of 

 these last more than any other. The ungueal phalanges re- 

 semble those of the Sloths, but with a bony sheath, like that of 

 the Ant-eaters, open above on the back of the phalanx. In the 

 inequality of the fingers, and particularly the great relative size of 

 the medius, it is like the Armadilloes and Ant-eaters. Similar 

 affinities to all these animals may be traced in the other bones 

 composing the metacarpus and phalanges. 



§ § '^ §. Posterior Extremity. 



Of this very little is known. Dr. Harlan describes* the 

 lower extremity of a femur, which, with a young tibia and a 

 calcaneum, were found in the White Cave. There is likewise 

 a tibia of an adult individual, found at Big-Bone Lick. If my 

 conjecture is right, we have also a metatarsal from the same 

 place; and two phalanges of the hind foot, from White Cave. 

 But what is most extraordinary, and a fact of high interest to 

 the geologist especially, one of the claws, in excellent preser- 

 vation, was procured from the same cave. 



From these portions it is, however, easy to detect no less dif- 

 ference between the hinder, than we have found to exist be- 

 tween the anterior extremities of the Sloth and the Megalonyx. 

 The tibia, in its average dimensions, is not much more than 

 twice as long as broad ; and though it does not much resemble 

 any of the co-ordinate animals in this part, it comes nearest to 

 the Megatherium. The union of the tibia and fibula into one, 

 which takes place in the Megatherium and the Armadilloes, is 

 not found in the Megalonyx ; or if they were slightly joined at 

 the upper extremities, the anchylosis was not so complete as 



* Journal Acad. Nat. Sc. Phila. vol. VI. 



