OREODON. 37 



Dentition. — The dentition of Oreoclon is remarkably distinct from that of any 

 living or any known extinct genus, and it indicates the combined habits of ruminat- 

 ing and suilline animals, or, in other words, it appears to characterize a ruminating 

 hog. 



The formula of the permanent dentition is as follows : — 

 .33 11 44 33-- 



^•n^T-l^"^Tl"-3-3 = ^^- 



The true molars are constructed after the type of those of recent ruminants; the 

 premolars approach most, among recent animals, those of the deer tribe; the canines, 

 those of the peccaries; and the incisors occupying both jaws, in this relation among 

 living ruminants, find their nearest representative in the camel tribe. 



Relative Position of the Teeth. — (PI. II. — VI.) The upper molars, internally, are 

 nearly parallel upon the two sides of the jaw, but externally they are convergent 

 forward from the second true molar, by reason of the gradual decrease in size of 

 the teeth in advance of this. Viewed laterally, they present a convexity down- 

 ward rather greater than that in the Deer. 



Each true molar, at its antero-external margin, projects exterior to, and a little 

 in advance of the contiguous margin of the preceding tooth, as among existing rumi- 

 nants, in Anoplotherium, Rhinoceros, etc. 



The fourth premolar, and in some specimens the third, project at their antero- 

 external margin exterior to the outer face of those preceding, but never in advance 

 of this point. 



The second premolar, on the contrary, has its anterior margin a little within the 

 position of the first, as if this had been pushed backward and outward to form the 

 small hiatus existing between it and the canine. 



The face increases slightly in breadth in advance of the premolars ; apparently 

 for the accommodation of the canines, which, at the base of their crowns, project 

 one-third their transverse diameter exterior to the first premolar. 



The hiatus existing between the upper first premolar and the canine, is only 

 sufficiently large to receive the point of the inferior canine. Between the upper 

 canine and the incisors there is usually, but not in all the specimens, a hiatus 

 smaller than the former, adapted to the accommodation of the outer angle of the 

 crown of the large lateral incisor below. 



The superior incisors are arranged in the arc of a circle greater than in the Wolf, 

 and they project vertically downward, and very little in advance of the position of 

 the canines. 



The inferior molars of the two sides are internally nearly parallel; and are 

 much more nearly so externally than the upper molars, from the breadth of these 

 being less uniform. Viewed laterally, the triturating surface of the former presents 

 a concavity corresponding to the convexity of the series above. 



The relation of the true molars and of the third premolar to one another, is the 

 same as in existing ruminants. The anterior margin of the second premolar is 

 placed within the position of the first, and the corresponding portion of the latter 

 holds the same relation to the canine ; apparently as if these teeth had been pushed 

 outward and backward in a jaw, in which little space could be spared to form, ante- 



