THE AMEKICAN BISONS. 43 



" Carpus — Metacarpus 

 Radius (Aussenseite) 

 Humerus mit Trochanter 

 Scapula vorderer Rand 

 Metacarpus mit Naviculare 

 Tibia aussen 

 Femur mit Trochanter 



Takino- the same method of comparison with five specimens of B. amcrica- 

 nus and two specimens of B. bonasus (= europceiis) as a basis, gives propor- 

 tions not differing essentially from Riitimeyer's, though the figures range 

 ten to fifteen per cent larger, being probably based on larger specimens. 



Carpus and Metacarpus 1. ) 1- ) 



Radius 1.260 1 3.680 (1.) 1.327 £ 3.901 (1.) 



Humerus (with Trochanter) 1.420) 1574) 



Scapula 1.940 1.836 



Metacarpus 1.400) 1.364) 



Tibia 1.680 ( 4.800 (1.130) 1.727 [■ 4.834 (1.155) 



Femur (with Trochanter) 



J 1.743 ) 



The differences between the two species in these proportions are very 

 slight, scarcely greater in fact than occur between different individuals of 

 Bison amcricanus. 



Dr. J. E. Gray placed the aurochs and American bison in different sections 

 of the genus Bison, the first of which, containing the aurochs, is character- 

 ized as having the " tarsi elongate, fore and hind quarters subequal," and the 

 other, containing the American bison, as having the " tarsi short, hinder 

 quarters very low." In the description of the aurochs he says again, " fore 

 and hind legs subequal ; tarsi elongate," contrasting it with " tarsus short, 

 hinder quarters very low," in his diagnosis of Bison amcricanus. The differ- 

 ence in height between the fore and hind quarters of the aurochs and 

 American bison is, as already shown, more apparent than real, owing to the 

 greater size of the pelvic region in the aurochs. The difference in the 

 relative length of the tarsus is also much less than one might infer from 

 Dr. Gray's diagnosis. 



In Bison americamts the proportional length of the metatarsal bone to the 

 length of the femur and tibia taken together is (in five specimens) as 29-31 

 to 100 ; in Bison bonasus (two specimens), as 28 to 100, showing an actual 

 slightly greater length of the metatarsal segment in Bison amcricanus. The 



