Peterson: Material Discovered in Uinta Basin. 43 



upward, while in 0. dysclerus the chin is turned u])ward more abruptly. 

 Although 0. dysodus may pertain to a different genus (? Limnocyon) 

 it seems preferable to retain it in Oxya;nodon, pending the discovery of 

 more material of both Oxyccnodon and Limnocyon in that horizon of the 

 Uinta formation in which the type was found. This decision is mainly 

 based upon the fact that a specimen representing a new species of 

 Limnocyon, vide injra, was found during the summer of 1912 at the 

 same locality where Oxycsnodon dysodus was obtained,- and which 

 differs from the latter. In this new form the mandible is proportion- 

 ally shorter, especially in the region of the premolars. The first 

 upper premolar is obliquely placed in the alveolar border, and the 

 premolars are crowded, while in 0. dysodus P- is directly fore-and-aft 

 and the premolars occupy proportionally a greater space. These 

 differences between the two specimens compared may be of generic 

 importance. 



M- in Oxyccnodon dysclerus has the paracone and metacone placed 

 closer together than in Limnocyon. In the latter genus P- and P- 

 have smaller heels and M- has one instead of two median tubercles. 

 Recently acquired material, representing the limbs of Oxyccnodon 

 dysclerus, described below, further show that the limbs are longer in 

 proportion to the skull than is the case in Limnocyon. 



2. Oxyaenodon dysclerus Hay (Plate XXXIV, Figs. 1-2). 



U. S. Geological Survey, Bull. No. 179, 1902, p. 759. (For synonymy see ante.) 



This species is represented by a well-preserved skull with the lower 

 jaws attached, portions of the vertebral column, and the fore-limb 

 of one individual. No. 3051. The specimen was found by the writer 

 on White River, Uinta County, Utah, in the same locality and in the 

 same horizon in which the type was obtained. It was found in a 

 fine-grained sandstone concretion in which it is still imbedded in half 

 relief, the skull and portions of the fore-limb having been more com- 

 pletely worked out for further detailed study and illustration. 



The differences between the present specimen and the type (No. 

 2515 of the American Museum) are very slight, judging from the 

 descriptions, the illustration, and actual comparison. 



The axis has a high neural spine and the cervical centra have stout 

 transverse processes, which project rather strongly backward. 



2 Mr. Peterson collected in 1893-95 the material upon which Osborn, Matthew, 

 Hay, and Wortman wrote. (Editor.) 



