0. C. Marsh — Notice of JVew ^Fossil Mammals. 331 

 Fig. 12. 



Figure 12. — Skull of Titanops elatus, Marsh; front view. One-eighth the 

 natural size. 



Allops serotinus, gen. et sp. nov. 



Another genus nearly related to Brontotherium is repre- 

 sented at present by a well-preserved skull, and various other 

 remains. This skull in its general form resembles that of 

 Brontotherium, but differs in having only a single upper 

 incisor, and the last molar has the posterior inner cone more 

 strongly developed. 



The superior dentition is as follows : 



Incisor, 1 ; canine, 1 ; premolars, 4 ; molars, 3. 



In the type specimen, the canine is small, extending but 

 little below the premolars. There is no diastema. The upper 

 premolars have a very strong inner basal ridge. The nasals are 

 very wide, expand forward in the free portion, and are notched 

 in front. 



The entire length of this skull is thirty-one inches (79 cm.), 

 the distance across the zygomatic arches twenty-one inches 

 (53 cm.), and the length of the horn-cores about ten inches 

 (25 cm.) 



This specimen was found near the top of the Brontotherium 

 beds in Dakota by Mr. J. B. Hatcher, who has done much 

 by his discoveries to increase our knowledge of this group. 



Tale College, New Haven, Sept. 24th, 188? 



