172 M. R. Thorpe — Oregon Tertiary Canidce 



near the Hellgate River, Montana, and is probably like- 

 wise of Upper Oligocene age. 



Measurements of Holotype. 



mm. 



Length of skull, occip. condyles to prosthion 143.5 



Diameter of postorbital constriction '. 21.9 



Diameter of brain-case, max 46 



Length of superior molar series 15.5 



Length of superior premolar series 37 



Pericyon socialis, gen. et sp. nov. 



(Fig. 3.) 

 Holotype, Cat. No. 12715, Y. P. M. Both rami, permanent dentition, 

 unworn. Upper Oligocene (upper John Day), Haystack Valley, John Day 

 Valley, Oregon. Paratope, Cat. No. 12737, Y. P. M., from Turtle Cove. 



Fig. 3. — Pericyon socialis, gen. et sp. nov. Holotype. X 2/3. 



Distinctive characters. — Slightly smaller than Daphce- 

 nus vetus Leidy; dental formula (lower jaw) 13, CI, P4, 

 M3 ; inferior premolars compressed ; P 3 has posterior 

 tubercle but very small posterior cingulum ; very prom- 

 inent posterior tubercle and large basal heel on P 4 ; M. x 

 has large and well developed metaconid and prominent 

 hypoconid; M 2 with two anterior cusps, a low hypo- 

 conid and a basin-shaped entoconid; M 3 nearly three 

 quarters as long as M 2 , with a small paraconid from 

 which extends inward, backward, and finally outward 

 a faint semi-lunar ridge ; masseteric fossa deep ; inferior 

 border of ramus more curved antero-posteriorly than 

 that of D. vetus, but about the same depth below the tooth- 

 row in each. 



