OREODON. 29 



ORi:€$DOIV. 



(Plates II.— VI.) 



In the Proceedings of the Academy of Natural Sciences of Philadelphia for 1848, 

 I described two fragments of an upper and a lower jaw of an extinct ungulate animal, 

 from the Bad Lands of Nebraska Territory, presented to the Academy by Mr. 

 Alexander Culbertson. The fragment of an upper jaw contained the last two 

 molars, that of the lower jaw the three true molars, and from the form of the teeth 

 I characterized the animal under the name of Merycoidodon Cidhertsonii. 



In 1851 I received from the Smithsonian Institution, and from Dr. Hiram A. 

 Prout, of St Louis, several fragments of skulls and jaws, obtained from the same 

 locality as the former. These contained the same form of true molars ; but, being mis- 

 led by a fragment of the face of a young animal containing a portion of the first 

 permanent premolar, followed by the entire first, and portions of the second and 

 third deciduous molars, in a verbal communication to the Academy,^ I referred 

 the specimens to two other distinct genera, to one of w^hich the name Oreodon 

 ■was given, and to the other that of Gotylgps. 



All these have since been satisfactorily determined to belong to a single genus, for 

 which I desire to retain the name Oreodon, in preference to Merycoidodon ; for all 

 the anatomical characters of the animal indicate it to have been a true ruminant, 

 and not merely like one in the form of its molar teeth. 



Oreodon is a remarkable and very peculiar genus of ruminant ungulates, constitut- 

 ing one of the links necessary to fill up the very wide gap between existing rumi- 

 nants and that exceedingly aberrant form of the same family, the extinct Anoplo- 

 tlierium of Europe and Asia. 



Of this genus I have been enabled to examine crania, more or less perfect, and 

 fragments of others; and teeth of numerous individuals of at least two, and probably 

 three distinct species, and can render our knowledge of the head of the animal 

 almost complete. 



Description of the Skull. — The form of the skull of Oreodon is so peculiar that I 

 know of none among existing ungulates with which to compare it nearer than that 

 of the Camel ; and yet this only approaches it in the form of the cranium proper. 

 Generally it has most resemblance to that of Anoplotlierium, but from this it strik- 

 ingly differs, in the existence of post-orbital arches as in all existing ruminants; in 

 the greater size of the orbits; in the presence of deep lachrymal depressions, rela- 

 tively as large as those of the Deer or of the extinct Bootherium; and in other 

 important particulars. The true molar teeth are decidedly of a ruminant cha- 

 racter; while canines and incisors exist in both jaws, and form with the molars 

 almost unbroken rows, as in Anoplotheriwn. 



Lateral View.—{V\. II. Figs. 1, 3 ; III. 2 ; V. 1; VL 3, 4, 6.) The side view of 



1 Proc. Acad. Nat. Sci., V. p. 237. 



