46 THE AMERICAN BI80N& 



Explanation of Table IX. 



]_ Bison americanus. Male, mounted skeleton (No. 91, Mus. Comp. Zoology), from near Fort Hays, 

 Kansas. 



2. Bison americanus. Very old male, unmounted skeleton, the bones mostly Ligamentously attached (Mus. 



Comp. Zoology), from near Fort Hays, Kansas. 



3. Bison americanus. Very old male, unmounted skeleton, the bones mostly ligamentously attached 



(Mas. Comp. Zoology), from near Fort Hays, Kansas. 



4. Bison americanus. Male, disarticulated skeleton (No. 10, Mus. Comp. Zoology), from near Fort 



Hays. Kansas. 



5. Bison americanus. Female, disarticulated skeleton (No. 11, Mus. Comp. Zoology), from near Fort 



Hays. Kansas. 



6. Bison americanus. Female, mounted skeleton (Xn. 92, Mus. Comp. Zoology), from near Fort Hays, 



Kansas. 



7. Bison banasus. Old male, mounted skeleton (No. 165, Mus. Comp. Zoology), from the Menagerie of 



Sehocnbrunn, received from the Vienna Museum. 



8. Bison bonasus. Young male, mounted skeleton (No. 11,514, National Museum, Washington), from 



the Vienna Museum. 



9. Bison bonasus. Male (measurements from Richardson's Zool. of the Voyage of the Herald). 



the animal at the shoulder and hip (as previously given); and show a slightly 

 greater average relative length of the hind limb in B. bonasus as compared 

 with B. americamu. The differences, however, are really much less than 

 different individuals of either species present when compared with each other. 



The skull of! Bison bonasus is rather longer perhaps than that of Bison ameri- 

 canus, hut the average difference in length is very slight. It would be often, 

 in fact, almost impossible to decide absolutely as to whether a skull from an 

 unknown locality belonged to one rather than to the other of the two spe- 

 cies, especially those of young individuals or females. Neither the teeth nor 

 \he relative size and form of any portion of the skull afford any absolutely 

 distinctive characters. The chief difference consists in the rather more mas- 

 sive character of the skull in Bison bonasus. The close resemblance in all 



ential features between the skulls of the two species is sufficiently indi- 

 cated in the subjoined table of measurements of a considerable number of 

 Bkulls of each npeciea 



The greater prominence and thickness of the orbital cylinder in the 

 aurochs has been cited by Rfltimeyer as a distinctive feature of the aurochs, 

 but in a comparison <>f Bkulls of corresponding ages the difference is not 

 apparent, the slightly greater size and thickness corresponding merely with 



the generally 1 *e massive character of the osseous Bystem of the aurochs. 



The difference is the nasal hones referred to also by the same author is 

 intangible, being equalled in different individuals of Bison amerioe 



