8 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.63. 



at the middle. In the Kansas specimen these dimensions are re- 

 spectively 345 mm. and 48 mm. It must be remembered that any one 

 of these bones may belong to the existing bison. It is, however, prob- 

 able that all belong to B. occidentalis. 



EXPLANATION OF PLATES. 

 \ Skull of Bison occidentalis Lucas. 



Pr-ATK 1. 



Figs. 1, 2. 



1. View from in front. X .14. 



2. View from behind. X .14. 



Pr.ATK 2. 



Figs. 1, 2. 



1. View of under surfiice. X .13o. 



2. View from left side. X .17. 



