PLATE CXIV 



Skulls of Allops marshi 



One-fifth natural size. (See pp. 508, 512, 513) 



A, Am. Mus. 1445, paratype, Cheyenne River, S. Dak., Chadron formation. Crushing from above has lessened the vertical diam- 



eters of this skuU. It is more massive than the type skull and less massive than that of Brontops dispar. 



B, British Mus. 4446M. This well-preserved skull differs from the type chiefly in the greater elevation of the occiput, accenting 



the deeply concave upper profile characteristic of aU Menodontinae. The dental measurements are given on page 508. 



C, Am. Mus. 501, type, South Dakota, probably Cheyenne River Badlands, Chadron formation. This specimen was at first placed 



in the genus Brontops near B. brachycephalus and B. dispar. It is, however, less brachycephalic, its horns have a trihedral 

 basal section, the canine is compressed anteroposteriorly, and the premolars and molars are of moderate breadth, with internal 

 and external cingula. This combination of characters is seen only in the genus Allops, and the upper premolars of the present 

 specimen closely resemble those of Allops serotinus. The upward pitch of the nasals is due to crushing. 



