1902.] Matthetv, A Horned Rodent from Colorado Miocene. 3^3 



sagittal crest for some distance back of the postorbital con- 

 striction. BullcB of moderate size; grinding series of teeth 

 near together anteriorly, divergent posteriorly. The teeth 

 decrease in size from p^ to m^ more 

 than they do in 5. nehrascensis or 

 S. peninstilatus; there is but one 

 fossette anterior to the external 

 enamel inflection on the type, while 

 our referred specimen of 5. nebra- Fig- 7- steneo_fih^ gradatns. Up- 



^ per molars X f. Type. No. 7007. 



SCensis shows two, neither near ex- John Day (? Dkeratherium Beds), 



Oregon. 



tinction, although the teeth have 



attained the same stage of wear. The external enamel in- 

 flection has given off a small fossette on the left premolar of 

 the type, but not on the right one ; in both type and referred 

 specimen the fossette of the posterior enamel inflection has 

 disappeared. 



4. S. pansus. The upper and lower jaws are the only parts 

 of the head known, and I have no certainly referable material 

 to asisst in determination of the characters. Professor Cope's 

 figures indicate an old individual, and apparently that the 

 posterior enamel inflection of the upper 

 teeth was more deeply impressed than in 5. 

 gradatiis, which it resembled in the presence 

 of but one fossette anterior to the median 

 enamel inflection. The form and propor- 

 tions of the molars, on which Professor Cope 

 relied to distinguish it from other species, 

 are merely a matter of age, as far as any 

 separation from 5. peninsulaHts and nehra- 

 scensis is concerned. The bullae are very 

 large, as in peninsulatus , which it most 

 nearly approaches as far as known, although 

 presumably distinct, as it is recorded as 

 found at a much higher horizon. 



5. S. montanus. Allied to 5. nehrascensis , 



Fig. 8. Stejieofiber mon- 

 tanus. Upper and lower 



BedT^of'smah''cre''eky but larger, with somewhat longer teeth, 



Montana (Lower Mio- 

 cene). 



complex. 



and enamel inflections deeper and more 

 The type is an old individual, whence the antero- 



