Vol. 6] 



Merriam: Virgin Valley and Thousand Creek. 



275 



premolars, to which reference has just been made, the Thousand 

 Creek specimen approaches Prosthennops more closely than to the 

 other American genera of the Suidae. 



The third upper molar (c, fig. 53) is the only molar preserved 

 complete. The enamel is much corroded so that the tuberculatum 

 is not entirely clear, but the tooth appears to be of the dicotyline 

 type. There is a small heel developed on the cingulum behind 

 the hypocone and metacone. The dimensions of this tooth are 

 near those in Prosthennops crassigenis. 



A large lower canine (fig. 52) occurring with this individual 

 is triangular in cross-section with a faintly expressed ridge on 

 the middle of the outer face. 



Measurements 



No. 11876 



P ; , anteroposterior diameter 10. mm. 



P 2 , transverse diameter 8.4 



P 3 anteroposterior diameter 11.2 



P 3 , transverse diameter 10.8 



M 3 , anteroposterior diameter 21.2 



M 3 , transverse diameter 15.3 



No. 11884 



P 3 , anteroposterior diameter 10.6 mm. 



P 3 , transverse diameter 11. 



Other remains accompanying this specimen include small 

 portions of the skull, a calcaneum, and the distal portions of two 

 metapodials. One of the metapodials shows a flattened lateral 

 surface above the distal end, indicating close contact with the 

 metapodial paired with it. 



THINOHYUS( ?), sp. 

 A large upper molar (no. 11854, fig. 55) from Virgin Valley 

 shows considerable resemblance to the form of M 3 in Thinohyas 

 occurring in the John Day Beds. The greatest transverse diam- 

 eter nearly equals the anteroposterior, as in M 2 , but the posterior 

 region is narrower than the anterior, and the posterior shelf on 

 the cingulum is more prominent than on any of the molars ex- 

 cepting M 3 . 



This tooth represents a large species, presumably belonging 

 in the hyotherine division of the Suidae rather than in the later 

 and more specialized dicotylines. 



