1916] Merriam-Stock-Moody : An American Pliocene Bear 107 



The Indarctos group is nearer to Hyaenarctos than to Arcto- 

 therium, and as suggested by Pilgrim 5 the discovery of a type inter- 

 mediate between Hyaenarctos punjabiensis and Indarctos salmontanus 

 might make it difficult to establish a generic separation between Ind- 

 arctos and Hyaenarctos. 



The occurrence in the Oregon Pliocene of a form closely allied to 

 an Indian Siwalik type suggests close faunal relationship of Asia and 

 North America in early Pliocene time. The presence of a form of 

 the Hyaenarctos type with characters tending toward those of 

 Arctotherium in the North American Pliocene also gives support to 

 the assumption that the American Arctotherium is derived from a 

 line passing near that of Hyaenarctos. It is now possible to consider 

 the origin of Arctotherium in America rather than in Eurasia. As 

 no bears of the Ursus type are known from the Pliocene of America, 

 we may conceive of Arctotherium as originating in North America 

 in the Pliocene and entering South America before Ursus was present 

 in the New World. This would account for the large Pleistocene 

 development of Arctotherium in South America in absence of Ursus. 

 though the two groups appear together in the North American 

 Pleistocene. 



A large lower carnassial of a bear-like animal (figs. 23a and 235) 

 from the brown coal of Tehuichila near the boundary between the states 

 of Hidalgo and Vera Cruz, Mexico, was thought by Freudenberg' ; to 

 resemble Hyaenarctos. This specimen was found in beds containing 

 a Hipparion fauna, and presumed to be of upper Miocene or lower 

 Pliocene age. An excellent cast of the Mexican specimen kindly 

 furnished by Dr. Freudenberg is available for comparative study. 

 This tooth resembles in many respects the lower carnassial of a 

 specimen referred to Hyaenarctos punjabiensis by Lydekker. 7 The 

 general form of both the trigonid and talonid portions of the tooth 

 is like that of Hyaenarctos, and the proportions compared in antero- 

 posterior diameter are approximately the same. Unfortunately the 

 Mexican specimen is broken in the region of the metaconid, but as 

 nearly as can be determined this portion of the tooth may not have 

 been widely different from that of the Indian genus. 



The occurrence of the specimen from Tehuichila is presumably 

 at a horizon not widely removed from that of the Rattlesnake Pliocene 



s Pilgrim, G. E., op. cit., p. 227, 191 4. 



a Freudenberg, W., Geol. u. Palae., Abb.. N. F., Bd. 9, p. 13, 1910. 

 "Lydekker, R., Mem. Geol. Surv. India, ser. 10, vol. 2, pi. 31, fig. 1, 1881. 



