409 



further evidence appears of the animal having been of the nature which 

 had been supposed from the appearance of the ungual bone. 



A puzzling circumstance occurred with respect to a metacarpal bone, 

 answering to the ring-finger, which appeared to be half as long again as 

 the metacarpal bone of the next, the middle finger. The explanation 

 of this singularity appeared to be truly difficult. In the sloths, hetero- 

 clites as they are in other respects, nothing similar appeared. In the 

 engraving of the skeleton of the megatherium, the same peculiarity was 

 however found to be depicted. 



It therefore now appeared not to be an accidental or monstrous con- 

 formation, and consequently something analogous might be expected 

 to be found among the living animals. This indeed was found to be the 

 case. In the Myrmecophaga jubata, one of the family of ant-eaters, the 

 metatarsal of the middle finger is more thick and short than all the 

 others ; that of the index is a little longer and thinner, and that of the 

 ring and of the little finger much more so. 



From a pit on the outside of the metacarpal bone of the index, there 

 appears reason for believing that a metacarpal bone of the thumb had 

 existed in this animal. In the fore-foot of the megalonix, therefore, 

 there would have been two complete fingers, the index and the middle 

 fingers : and besides these, the vestiges, at least, of three more. But 

 one of these three, at least, was more than a vestige, since there was a 

 third ungual bone, which in all probability was that of the annulare. 



The examination of the radius and of the ulna gave reason for con- 

 cluding that they also had belonged to an animal of the sloth kind, and 

 appeared perfectly to accord with the preceding bones of the fore-foot. 



From the information yielded by the examination of the preceding 

 bones, no doubt could exist of their having belonged to an animal which 

 might be considered as either belonging to the sloths or ant-eaters. In 

 determining under which of these genera the megalonix should be placed,, 

 the tooth which had been obtained by M. de Beauvois was entirely de- 

 cisive, since the ant-eaters have no teeth at all. An examination of this 



VOL. in. 3o 



