CARNIVORA. 



261 



lost notably so in the Orang. The hand of the Mada- 

 iscar Aye- Aye (Chiromys) is remarkable for the extreme 

 ttenuation of the bones of the third digit. 



In the Carnivoma, the scaphoid and lunar bones always 



:oalesce into a single scapho-lnnar bone (Fig. 88, si), with 



hich it is probable the centrale is united, as it never appears 1 , 



a distinct bone, except sometimes in very young animals. 



'ig. 88. — Bones of the carpus of a Bear (Ursus americanus), %. si scapho-lunar 

 bone ; c cuneiform ; p pisiform ; u unciform ; m magnum ; td trapezoid ; tm tra- 

 pezium ; rs radial sesamoid ; i — v the metacarpals. 



'he radial accessory ossicle or sesamoid (rs) is generally 

 >resent. All have five digits, with the complete complement of 

 >halanges, except the Hyaena, in which genus the pollex is 

 'presented only by a rudimentary metacarpal. This digit is 

 isually much reduced in size, and often, as in the Dog, docs 

 lot reach the ground in walking. It is best developed in 

 le bears and allied forms. The first metacarpal is never 

 lore freely moveable than any of the others. As a general 

 ile the middle digit is somewhat the longest, the second and 

 >urth nearly equal to it, the fifth shorter, and the first the 

 jhortest. 2 



1 See B. G. Wilder, "On the Composition of the Carpus in Dogs." 

 hill. Cornell University, Vol. I. p. 301, 1874. 



" 2 The fissiped Carnivora have been divided into two groups, accord- 

 to the position of the feet in walking — the Plantigrade, or those 

 lat place the whole of the palmar and plantar surface to the ground ; 



