238 [August, 



the aid of several fragments of upper maxillae containing perfect teeth, from seve- 

 ral otiier individuals of the same animal, received from the Smithsonian Institu- 

 tion, through Prof. Baird, the dentition in a great measure can be made out. 



The teeth form nearly a continuous row, as in Anoplotherium, the only inter- 

 val, being one of i of an inch between the canine and the first premolar. 



The canine is broken away, but judging from the fragment of the root, which 

 is 4 lines in diameter antero-posteriorly, it was well developed. The anterior 3 

 premolars are too much broken to obtain any knowledge of their form. The 

 fourth is like one-half of the true molars, and resembles closely, the correspond- 

 iug tooth of Cervus. 



The 3 true molars have exactly the same form, and very nearly the size as the 

 2 posterior superior molars, described in the Proceedings of this Academy, 

 Vol. iv. p. 47, as characterizing a genus under the name of Merycoidodon. 

 From the latter fact it might be readily supposed, that the fossil before us 

 belonged to Merycoidodon, but a fragment of a face of a smaller animal now ex- 

 hibited, received from Prof. Baird, contains the first and second true molars, mu- 

 tilated, which have the same form as the corresponding teeth of the preceding fos- 

 sil, but the fourth premolar has three cusps instead of two, like the former, indi- 

 cating that we may have animals of different genera, with true molars identical 

 in form. 



Neither of these fossils Dr. L. suspected belonged to Merycoidodon, for in it 

 the enamel of the teeth is rougher than in the former. 



For the first he proposed the name of Oreodon. 



The face of Oreodon has a remarkably cat-like expression, being depressed, 

 and as broad between the malar bones, as it is long. The orbits are closed poste- 

 riorly as in the ruminants, by the junction of the post-orbital process of the 

 OS frontis with that of the malar bone, and present outward, foiward, and up- 

 ward, less in the latter two directions than in the cats, but more so than in the 

 ruminants. 



Just anterior to the orbit, is a remarkably large lachrymal depression or lar- 

 mier, relatively several times larger than that of Cervus virginianus. 



The glenoid cavity is a broad, extensive, nearly flat surface, as in the rumi- 

 nants. 



The posterior portion of the head, relative to the face, is very narrow, 

 and resembles in its form the fragment of a cranium described in Vol. v., of the 

 Proceedings, p. 90, as characteristic of a genus under the name of Eucrotaphus. 



The temporal fossae are as large as in the carnivora, and lead to the impression, 

 with other characters given of the head, that flesh probably formed part of the 

 food of the animal. 



The species Dr. L. named Oreodon priscum. 



Measurements. 



Length of line of 3 true molars, 



" " 4 premolars, 



Breadth of middle true molar, ..... 



Diameter of orbit, ........ 



Breadth of face between malar bones, below the orbits, . 



Length from same point to root of canine tooth, 



Breadth of cranium just anterior to the meat. aud. ext., . 



