228 M. R. Thorpe — John Day Promerycochoerij 



Measurements of Holofype. 



mm. 



Total length of skull, approx 380 



Bipostglenoid diameter 133 



Bizygomatic diameter 246 



Length, of superior molar series 81 



Length of superior premolar series , 90.5 



Length of superior dental series, inc. canine 179.5 



Depth of malar below middle of orbit 38.5 



Max. width of cranium 94 



Diameter of postorbital constriction 62.4 



Max. height of zygoma above glenoid surface 71 



Width of frontals above middle of orbit 110.6 



Width of face at infra-orbital foramina 85 



Length of inferior molar series 86.5 



Length of inferior premolar series 77.5 



Depth of ramus from condjde to angle 133 



Length of ramus from condyle to angle 276 



Promerycochocnis leidyi (Bettany). 



Holotype in Woodwardian Museum, Cambridge. Upper Oli- 

 gocene (upper John Day), Bridge Creek, John Day River, 

 Oregon. Figured by Bettany, Quart. Jour. Geol. Soc, London, 

 32, pi. 18, 1876. 



Specific characters. — Lacrymal fossa conical and deep ; 

 prominent lacrymal tubercle on anterior orbital margin ; 

 infra-orbital arch slightly deeper than in P. superhus, and 

 from above downward presents first a convexity, secondly 

 a broad groove, and thirdly another convexity ; orbit 

 nearly circular, more vertically placed and directed more 

 outwardly than in P. superhus; postgienoid processes 

 much less broad and proportionally deeper than in 

 P. superhus; an angle of 45^ is formed between the 

 median line and a line passing through the postgienoid 

 and paroccipital processes; length of skull about 12 

 inches ; palate moderately produced ; bullae large, oval, 

 and extend below level of postgienoid process ; anterior 

 part of squamosal juts out from malar below postorbital 

 bridge. 



Cope,^^ in describing P. leidyi, said that '^a line drawn 

 through the postgienoid and paroccipital processes makes 

 (an angle of) 90° with the middle line" in this species. 

 The angle in our specimens, as well as in the type accord- 

 ing to Bettany, is 45°. 



" Op. cit., p. 521. 



