586 THE BEIDGEE EPOCH. 



a large, erect horn-core. The base is very massive, subquadrate in section, 

 and flattened in front. Posteriorly, it presents a very shallow groove, 

 which is bounded on the outside by a low ridge. The shaft expands 

 gradually, and is proportionally flattened from behind forward. The 

 posterior face is flat; the anterior gently convex. The extremity is trans- 

 verse-convex, and pitted for cartilaginous or corneous attachment. These 

 horns stand on the parietal bones The frontals extend to their bases, and 

 send a laminar expansion backward to the margins of the lateral and 

 posterior crests, covering the parietal in the fundus of the basin, which the 

 former inclose. 



The median horns are very stout, and are connected with the posterior 

 by an acute supratemporal ridge. Their inner face is composed to near the 

 apex, of the nasal bones. Where they terminate, the apex contracts, and is 

 composed of a cylindric production from the maxillary. The section of 

 these cores at the middle is subquadrangular, and longitwdinally oval at 

 the base. 



The extremity of the nasal bones is small and contracted, and is ex- 

 tensively overhung by the cornice-like, flat cores above them. Thias the 

 end of the snout has a bilobate outline when viewed from above. 



The occipital face is concave in vertical section, and presents a V- 

 shaped depression, witlv the angle downward, and a low ridge on the mid- 

 dle line to the transverse superior border. 



Measurements. 



u. 



Width of the foramen magnum and occipital condyles 2100 



Elevation of occiput (8 inches) 2500 



Width of basin between lateral crests 3250 



Height of posterior horn-core (7 inches) 2300 



Width of base of posterior horn-core anteroposteriorly 1300 



Width of base of posterior horn-core transversely 0900 



Width at summit 1230 



Height of median horn-core 1750 



Diameter of base anteroposteriorly 1000 



Diameter of base transversely 0800 



Diameter of summit 0650 



Projection of nasal cornices beyond apex 0630 



Length of posterior molar, crown 0450 



Width of posterior molar, crown 0550 



This species is equal in size to the largest known from the Bridger 

 formation. It diff'ers from Loxolophodon cornutus in the posteriorly-truncate 



