3o6 



THE EVOLUTION OF MAN. 



loped. Finally, in the Horse, only one digit, the third, is 

 perfectly developed (Fig. VI., 3). And yet all these diverse 

 fore-feet, as also the hand of the Ape (Fig. 271) and the 

 human hand (Fig. 272), have originated from the same 

 common five-fingered parent-form. This is proved, not only 

 by the rudiments of the aborted digits, but also by the 

 homologous disposition of the wrist-bones (Fig. 273, a-p). 

 (Vide supra, p. 124.) 



The same story is also told by the germ-history of the 

 limbs, which is originally identical, not only in all Mammals, 

 but in all Vertebrates. However different the limbs of the 

 various Skulled Animals (Craniota) afterwards appear in 

 their fully developed state, they nevertheless all originate 

 from the same simple rudiment. (Cf. Plates VI. and VII., 



4- 3 



Fig. 273. — Skeleton of hand or fore-foot of six Mammals. I. Man; II. 

 Dog; III. Pig; IV. Ox; V. Tapir; VI. Horse, r, Radius; u, ulna; 

 a, scaphoid ; b, semi-lunar ; c, triquetrum (cuneiform) ; d, trapezium ; e, 

 trapezoid ; /, capitatum (unciform process) ; g, hamatum (unciform bone) ; 

 f, pisiform; 1, thumb; 2, digit; 3, middle finger; 4, ring finger; 5, little 

 finger. (After Gegenbaur.) 



