90 ON THE EXTINCT MAMMALIA OF 



A skull of nearly similar proportions, but with larger molar teeth, is represented 

 in plate iii of '' The Ancient Fauna of Nebraska." The two specimens probably 

 belonged to males. 



12. The fore part of a skull and lower jaw of a moderately robust individual, but 

 less than that last described. The sagittal crest, though wanting, is seen to have 

 extended the length of the parietal. The latter is deeply and widely notched for the 

 recej)tion of the summit of the frontals. Orbits oval. Face robust ; above strongly 

 convex. Nasals broad, convex. Posterior nasal triangle acute; sixteen lines long, 

 ten and a half lines broad. 



13. The fore part of a skull, without the lower jaw; nearly like the corresponding 

 portion of the specimen last described, being slightly less robust. Orbits sub-rotund. 

 Teeth slightly smaller than in the last specimen. 



14. The anterior extremity of a skull, somewhat crushed, about as robust as the 

 corresjionding portion of the last two specimens. Lachrymal fosste somewhat 

 narrowed and deep. Nasals broad, nearly flat. Posterior nasal triangle obtusely 

 rounded, fourteen lines long and ten and a half lines wide. Teeth of the usual size, 

 except the canines, which are large, though not of the largest size. They are but 

 little worn, and the crown of the lower canine is half an inch in both length and 

 breadth. 



15. The greater portion of a skull without the lower jaw, much smaller than the 

 corresponding portion of any of the preceding specimens. The specimen is not larger 

 than the corresponding portion of a large specimen supposed to belong to the smallest 

 species of Oreodon, and the same is the case also with the true molar teeth, the only 

 ones preserved in the specimen. The other anatomical characters indicate it to be- 

 long to Oreodon Oulbertsoni, — viz. : the comparatively large orbits, the large and deep 

 lachrymal fosste, the acute posterior nasal triangle, and the small auditory bullos. 

 The forehead and top of the face, are flatter than usual. The fore part of the 

 parietal forms a wide notch for the reception of the frontals. The nasals are nearly 

 flat and moderately wide. The posterior nasal triangle is thirteen lines long and 

 eight wide. 



IG. A fragment of a skull, consisting of the greater portion of the left side of the 

 face without the lower jaw. The fragment has been derived from a skull rather 

 smaller than usual, though larger than in the last-described specimen. The forehead 

 is more convex than usual at the side, and the back portion of the nasal bones more 

 depressed. Orbit oval ; lachrymal fossa moderately large. Teeth small as in the 

 last-described specimen. Posterior nasal triangle obtuse, laterally sigmoid, twelve 

 lines long and nine lines broad. 



