170 M. R. Thorpe — Oregon Tertiary Canidce 



bital constriction narrow; brain-case moderately large; 

 junction of temporal ridges slightly beyond postorbital 

 constriction; zygoma expanded; sagittal crest low; bullae 

 narrow and ovate ; masseteric fossa large and deep, with 

 long axis nearly horizontal; coronoid low and angle 

 heavy. In the Yale specimen, P 1 is quite close to the 

 canine, a condition analogous to that in M. brachyops 

 Merriam. An individual variation of No. 12705 is the 

 possession of five inferior premolars in the right ramus. 

 The accessory premolar is of nearly equal size with P x . 

 The posterior basal heel of P 4 is robust, as well as the 

 posterior tubercle of the same tooth. P 3 has a small 

 posterior cusp and small basal tubercle. 



Measurements. 

 (Cat. No. 12705, Y. P. M.) 



mm. 



Length of skull, prosthion to occip. condyles, inc 144 



Bizygomatic diameter 98 



Diameter of postorbital constriction 20 



Diameter of brain-case, max 47 



Length of ramus, max 105.5 



Depth of ramus below middle of M t 19.3 



Length of inferior dental series, with canine 66 



Length of inferior premolar series 29 



Length of inferior premolar series, with accessory premolar 32 

 Length of inferior molar series 26 



Mesocyon josephi secundus, subsp. nov. 



(Figs. 1 and 2.) 

 Holotype, Cat. No. 10063 (skull), Y. P. M. Upper Oligocene (middle 

 John Day), John Day Basin, Oregon. 



Distinctive characters. — Premolars crowded and no 

 diastemata between the molars and canine ; P 2 obliquely 

 placed, much the same as the corresponding tooth in 

 Cynodesmus thobides Scott; P 3 has a small posterior 

 tubercle in addition to the posterior basal one; canine 

 more ovate in cross-section; molars and P 4 increased in 

 size and P 2 decreased. 



In comparison with M. josephi, sensu stricto, the new 

 subspecies differs in the characters noted above, and in 

 the fact that the molars of the latter are about one third 



