1916] Merriam— Stock-Moody : An American Pliocene Bear 



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in Hyaenarctos the deuteroeone tends to take the same position. In 

 Arctotherium, and in bears of the JJrsus type, the deuteroeone is 

 shifted far back and away from what is considered a normal position 

 of this tubercle in the modern Carnivora, and is commonly situated 

 opposite the notch between proflocone and tritocone. The protostyle, 

 which is so largely developed in the Oregon specimen and in 

 Hyaenarctos, may be suggested in some arctothere specimens, and is 

 figured by Blainville 1 in his illustration of the dentition of Tremarctos 

 ornatus, the Recent South American relative of the arctotheres. It 

 is therefore possible that a protostyle was at one time present on 

 P* of Arctotherium. 



The posterior upper molars (M-) (figs. 8a to 9) of the bear from 

 the Rattlesnake beds most nearly resemble those of the ursid type 

 described by Pilgrim 2 from the middle or upper Siwalik beds of 

 India under the name of Indarctos salmontanus (fig. 12). M= of 

 specimen 22362 resembles the type of I. salmontanus in its unusual 

 relation of width to anteroposterior diameter, and in the stage of 

 development of the heel. The anteroposterior and transverse diam- 

 eters are almost identical with those of the type of /. salmontanus. 

 The heel is a trifle longer in the Oregon specimen, but tends to be 

 slightly wider in the Indian form. The difference in width of heel is 

 possibly due in some part to difference in stage of wear in the speci- 

 mens compared. As in I. salmontanus, the paracone and metacone of 

 no. 22362 are clearly defined, the paracone being considerably larger 

 than the metacone. In /. salmontanus the antero-internal region 

 of the tooth consists of a large ridge divided into two tubercles of 

 which the anterior is the larger. In the Oregon specimen the heavy 

 antero-internal ridge is present, but the teeth are too much worn 

 to show distinctly whether this area was divided into two elements. 

 On the left tooth such a separation is suggested. In no. 22362. as 

 in /. salmontanus, there is evidence of a large tubercle immediately 

 behind the antero-internal ridge, corresponding evidently to the 

 hypocone. This tubercle appears somewhat larger in Pilgrim's figure 

 of I. salmontanus than it is in the left tooth of no. 22362. On the 

 right tooth the hypocone may have been somewhat larger. The ex- 

 treme posterior end of the heel consists of a transverse ridge which is 

 largely worn down. 



The proportions of the various areas of the tooth in no. 22362 

 are near those of the type of Indarctos. The anteroposterior diameter 

 of the paracone is slightly less than it measures on Pilgrim's figure of 



