106 University of California Publications in Geology [Vol. 10 



bility of these two upper teeth tells the story with more detail and 

 gives expression to the closer affinities. The few skeletal elements 

 present, though leaving much to be desired, show characters of high 

 value in estimating the more intimate relationships of this form. 



The Oregon Pliocene bear approximates the characters of Inclarctos 

 salmontanus Pilgrim in the structure of M-, the only available tooth 

 representing that genus. The characters seen in the type of Inclarctos 

 and in the Oregon specimen are not found in other known forms. 

 These characters arc must nearly approached in M- of Hyaenarctos, 

 Arctotkerium, and Aeluropus; and are intermediate between those 

 of Hyaenarctos and Arct other ium. In the characters of P- the Oregon 

 specimen docs not differ essentially from the several known species 

 of Hyaenarctos, but is distinctly different from Arct other ium, 

 Aeluropus, and all other known forms referred to the bear group. 



If as is indicated by the characters of M- the Oregon form belongs 

 to the same general group of bears as Inclarctos salmontanus, and shows 

 approximately the same stage of evolution, it seems probable that the 

 Siwalik Inclarctos also possessed the Hyaenarctos type of P-. From 

 slender evidence furnished by strength of the maxilla and form of a 

 small portion of the posterior border of the alveolus of I Ji , Pilgrim 4 

 inferred that P- of I. saliimutanus was large and possessed a distinct 

 inner root; and that its inner cusp or deuterocone did not occupy 

 an extreme posterior position as in Helarctos, in all modern bears, 

 and in the Pliocene and Pleistocene types referable to Ursus. With 

 such evidence as is at hand it may be assumed that P- of Pilgrim's 

 Inclarctos was not materially different from that in the Oregon 

 specimen. 



The characters of the massive limb elements of the Oregon speci- 

 men, so far as they are known, suggest the limb type of Hyaenarctos, 

 and indicate a rather wide separation from Arctotherium. 



The sum of the known characters of the Oregon bear, specimen 

 22362, represent a type near Hyaenarctos, but tending toward Arcto- 

 therium in the development of its last upper molar. The Oregon 

 form cannot be sharply separated from the Siwalik type of Inclarctos 

 on the basis of available material. Differences in proportions of the 

 tubercles of M2 suggest the specific divergence which is to be expected 

 in forms found in regions so widely separated geographically as India 

 and Oregon. The Oregon form may be referred tentatively to the 

 genus Inclarctos with the specific name oregoneusis. 



i Pilgrim, G. E., Becords, Geol. Surv. India, vol. 44, part 3, p. 230, 1914. 



