THE EVOLUTION OF THE HUMAN FOOT. 529 



antero-internal facets on the astragalus, M. Volkov showed that 

 monkeys possess the same peculiarity. In the chimpanzee and the 

 gorilla, however, there is a distinct tendency for these facets to become 

 united. The same tendency is observed in bears and all walking ani- 

 mals; finally in man, and especially in man of the so-called higher 

 races, it is not rare to find the two facets completely blended, a feature 

 less commonly found elsewhere. The separation of the antero-internal 

 facets should be considered an atavistic character. 



Scaphoid. — As M. Volkov has well remarked, the variability of this 

 bone essentially depends upon that of the astragalus and first cuneiform 

 which itself has a relation with the development, separation, and mobil- 

 ity of the first metatarsal and the first toe, which are, as is well known, 

 characteristic of the tree-dwelling animals. 



In the American monkeys, whose foot is especially adapted to an 

 arboreal life, and who consequently have quite a mobile great toe, the 

 inner edge of the scaphoid is very thick. It is less so in the monkeys 

 of the Okl World, who are even 

 surpassed in this respect by the 

 orang among the anthropoids. In 

 the lower races of man the inniM' 

 border of the scaphoid — that is to 

 say, its tul)erosity (whose real 

 significance, we may say in pass- 

 ing, has been so well determined 

 by M. Volkov) — is markedly bet- 



, • Fk;. 9.— Scaphoid (po: tt-rior view). I, Gorilla. 



ter developed than Ul l!iUropeanS, n, Negro, in, European. S, tubercle of the 



a character evidently depending scaphoid. 



on the fact that with them the first toe, together with the head of the 



astragalus, is much less divergent. 



M. Volkov has also directed his attention to the glenoid cavity hy 

 which the scaphoid articulates with the astragalus. He saw very 

 clearl}' that this articular facet is, as one might expect, ovoid and 

 much elongated from without, inward, in climbers, square, on the 

 contrai'v. and slightly elongated in walkers. He established, for this 

 articular surface, an index which increases from the climbers to the 

 walkers, that is to say, among the monkeys from the Cebidse to the 

 Pitheci, Among anthropoids the orang appears to present, in this 

 regard, an inexplicable anomaly; though he is the most arljoreal of 

 his class he possesses an index higher than the others; this exception 

 is, however, easy to understand and even confirms, in my opinion, in 

 a remarkable w^ay, the general rule al)ove enunciated. The orang is, 

 indeed, the most arboreal of the anthropoids, and, on this account he 

 shows a marked tendency toward an atrophy of the fii'st toe (the first 

 digit of the hand is likewise absent in a certain number of species of 

 the ])rimates, notably in the Colobus, one of the most characteristic 

 arboreal Cebidte). We are thus able to explain wh}- the orang. 



