The difference between the Megatherium and Sloths in the proportions of the 

 fore and hind extremities is pointed out ; the existence of the pecuUar charac- 

 teristics of the scapula of the Sloth in the same bone of the Megatherium is 

 dwelt on with emphasis equivalent to the value of such evidence of the real 

 aflSnities of the fossil ; and the marked degree in which the Megatherium differs 

 from all other great quadrupeds with which it might be compared on account 

 of its size, in possessing complete clavicles, is set forth. The humerus, ulna, 

 and radius are described in some detail. The organization of the fore-foot is, 

 however, involved in obscurity, from the faulty manner in which Cuvier believed 

 the bones to have been articulated; and he regrets that MM. Pander and 

 D'Alton have not thrown further hght on the subject*. After a comparison of 

 their figures with the bones of the fore-foot in existing Edentata, Cuvier con- 

 cludes that the fore-feet of the Madrid skeleton are transposed, the right being 

 on the left and the left on the right side ; that the index, medius, and annular 

 digits were the only ones provided with claws ; that the thumb was clawless, 

 and the little finger rudimental and concealed, in the living Megatherium, under 

 the skin ; the hand being thereby specially formed for cleaving the soil and 

 digging, like that of the Dasypus gigas. 



Names are applied by Cuvier to certain bones of the carpus, none of which 

 had before been determined. M. Laurillard adds, that the bones of the Mega- 

 therium received by the Royal College of Surgeons confirm Cuvier's suspicion 

 of the incorrect restoration of the carpus, but not of the transposition of the 

 fore-feet, in the Madrid skeleton ; and that they seem to indicate the hand of 

 the Megatherium to have had the greatest analogy to that of the Great Ant-eater 

 {Myrmecophaga jubata\) . 



All the chief characters of the pelvis of the Megatherium are truly pointed 

 out by Cuvier and Laurillard. The femur, tibia, and fibula are fully described. 

 The difference between the Sloth and Megatherium in the vertical position of 

 the astragalus in the latter, and their resemblance in the partial convexity of the 

 scaphoid towards the astragalus are indicated. Besides these bones of the tar- 

 sus Cuvier recognizes the cuboid bone ; a cuneiform , supporting the largest toe ; 

 and another bone representing, apparently, both the remaining two cuneiform 



* Recherches sur les Ossemens FossUes, 8vo, 1836, vol. viii. p. 354. f Loc. cit. p. 356. 



