NO. 1172. 



I HE FOSSlh BISON OF NORTH AMERICA— LUCAS. 



763 



right angles to the longitudinal axis of the skull, so that a line drawn 

 across the back of the cranium misses them completely, their tips 

 being 3 inches within (anterior to) the line. 



In tliis respect all specimens of B. antiquus differ very decidedly from 

 any that have been referred to B. crassicornis, even such imperfect speci- 

 mens as Eichardson's type or the similar specimen fignred herein on 



Fig. 2.— differences in curvature ketween the horn cores of bison ceassicoenis and bison 



ALLENI. 

 The liKht line distiDguishcs Bison alleni, the heavy liae JBiton crassicomit 



Plate LXXV. This being the case, none of the Alaskan specimens 

 can by any possibility be referred to Bison antiquus, and, as previously 

 stated, the type stands. 



Bison crassicornis may be distinguished from B. alleni, the species 

 which it most nearly resembles, by the lesser curvature of the horn 

 cores, which are also stouter, more flattened on the superior iace, and 

 more elliptical in section than are those of B. alleni. These differences 

 are evident enough in the specimens, but not in small ligures. 



