328 O. C. Marsh — Notice of New Fossil Mammals. 



Brontops dispar, sp. nov. 



A smaller species of this genus is represented at present by 

 a nearly complete sknll with lower jaws and entire dentition. 

 The sknll is less massive, and proportionately more elongate 

 than in the type species, and the lower jaw more slender. 

 The latter is shown below, in figures 7 and 8, which also 

 illustrate some of the generic characters. 



The skull of a young animal, apparently of this species, is 

 represented in figures 5 and 6. The sutures are many of them 

 distinct, especially those in the facial region, and thus the ele- 

 ments of the horn-cores, in this genus at least, can be readily 

 determined. The front of the elevation is formed by the 



Fig. 7. 



Fig. 8. 



Figure 7. — Lower jaw of Brontops dispar, Marsh; side view. 

 Figure 8. — The same jaw; ,top view. 



Both figures are one-eighth natural size. 



nasal, and the main portion by the frontal. The maxillary 

 contributes only the outer face of the base, but in some of the 

 other genera, its share appears to be larger. 



The specimens above mentioned were found in the Bronto- 

 therium beds of Dakota, by Mr. J. B. Hatcher of the U. S. 

 Geological Survey. 



m 



Menops varians, gen. et sp. nov. 



The present genus is most nearly related to Diconodon, and 

 its molar teeth agrees with that form. It differs in the 



