1916] Chandler: Skull and Dentition of Bison antiquus 



127 



cores there is a 33 per cent difference between the two sexes, resulting, 

 of course, in the females having considerably more slender horns. The 

 measurements also show that the neck of the horn-cores, i.e., the por- 



Figs. la and lb. Bison antiquus Leidy, J 1 . Cranium and horn-cores. No. 

 19478, X Vs, John Day region, Oregon. Fig. la, dorsal view, perpendicular to 

 forehead; fig. lb posterior view, at right angles to dorsal view. 



Figs. 2a and 2b. Bison antiquus, Leidy, J. Cranium and horn-cores. No. 

 21151, X %, Eancho La Brea beds. Fig. 2a, dorsal view; fig. 2b, posterior view. 



tion between the forehead and the rugose horn-covered portion, is of 

 smaller caliber than the base of the horn-core itself in the males, but 

 is greater in females. 



