Article VII.— RESTORATION OF OXY^NA LUPINA 

 COPE, WITH DESCRIPTIONS OF CERTAIN NEW 

 SPECIES OF EOCENE CREODONTS. 



By J. L. WORTMAN. 



Plate VII and Three Text Figures. 

 Family OXY^NID^. 



This family of the Creodonta was the most specialized in cer- 

 tain ways of any of the primitive flesh-eaters of Eocene times, 

 and apparently occupied the same position with reference to the 

 remainder of the fauna that the modern Felidse do to the existing 

 fauna. In the matter of dental equipment it is surprising to find 

 that even as early as the Wasatch this family had developed a 

 sectorial dentition almost if not quite as effective as that of the 

 modern Cats. In other respects, howev-er, they were far in- 

 ferior ; this is particularly seen in the small brain capacity, as 

 well as the comparatively smaller, decidedly weaker limbs with 

 shorter, more spreading feet, provided with flatter, fissured, non- 

 retractile claws. 



The origin of the family is completely unknown at the present. 

 They begin with several species abruptly in the Wasatch deposits 

 of both the San Juan and Big Horn beds without any known 

 predecessors in the underlying Torrejon. For this reason there 

 can be very little doubt that they represent migrants from another 

 region, probably northern Asia, which came with the Corypho- 

 donts, Artiodactyles, Perissodactyles, Primitive Dogs, as well as 

 many other types whose existence begins so abruptly in the 

 Wasatch beds of North America. 



According to our present knowledge the family represents a 

 perfectly natural grouping of the known species, and is easily 

 distinguished from the other groups of typical Creodonts that 

 had developed a more or less perfect sectorial dentition. A con- 

 venient distinction of these families may be made upon the 

 enlargement of a special molar in the lower jaw ; it is as follows: 



I. Third lower molar enlarged, — Hy^nodontid^. Includes the genera 

 Palaosinopa, Sinopa, Proviverra, Cynohycenodon, Pkrodon, Hycenodon. 



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