XVI.] CARNIVORA. 261 



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

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

 attenuation of the bones of the third digit. 



In the Carnivora, the scaphoid and lunar bones always 

 coalesce into a single scapho-liinar bone (Fig. 88, sl\ with 

 which it is probable the centrale is united, as it never appears^ 

 as a distinct bone, except sometimes in very young animals. 



Fig. 88. — Bones of the carpus of a Bear {Ursns americaiuis^, h. si scapho-luiiar 

 bone ; c cuneiform; / pisiform ; it unciform ; ;;/ magnum; td trapezoid; tin tra- 

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



The radial accessory ossicle or sesamoid (rs) is generally 

 present. All have five digits, with the complete complement of 

 phalanges, except the Hysena, in which genus the poUex is 

 represented only by a rudimentary metacarpal. This digit is 

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

 not reach the ground in walking. It is best developed in 

 the bears and allied forms. The first metacarpal is never 

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

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

 fourth nearly equal to it, the fifth shorter, and the first the 

 shortest.^ 



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

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



■^ The fissiped Carnivora have been divided into two groups, accord- 

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

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



