with Descriptions of New Genera and Species. 107 



Nos. 11011 and 12320 are probably males, while No. 

 12319 is more delicately proportioned and may be a 

 female. In the latter, the nasal bones are mudi more 

 narrow, the orbits smaller, and the whole skull and jaws 

 less robust, than in the other two. 



//o//, rvPE 

 Y p. M 



Fig. 10. — Eporeodon perhullatus, sp. nov. Holotype. Left half, superior 

 view. X 2/5. 



Measurements of Holotype. 



mm. 



Total length of skull 227 



Bizygomatic diameter 138 



Superior molar-premolar series, length 95 



Superior premolar series, length. 47 



Diameter, postorbital constriction 37.5 



Ramus, max. length 186 



Inferior molar series, length 52 



Inferior dental series, with P^, length 102 



Bulla, ant.-post. diameter 31.3 



Transverse diameter 25 



Vertical diameter 27 



Oreodontoides oregonensis, snbgen. et sp. nov. 



(Figs. 11-13.) 



Holotype, Cat. No. 12329, Y. P. M. Upper Oligocene (upper John Day), 

 Turtle Cove, John Day Elver, Oregon. Collected by William Day in 1875. 



Distinctive characters. — Size small, length less than 

 that of E. trigonocephalus ; muzzle pointed ; face narrow ; 

 orbits nearly round, looking chiefly outward, but some- 

 what upward and forward; cranium very full; no sag- 

 ittal crest, as frontal ridges do not unite; postorbital 

 constriction very wide; skull depressed at each extrem- 

 ity; lacrymal fossae well marked, but small; meso- 

 cephalic. The sides of the meso- and metastyle of M^ are 

 straight, giving the metacone a square outline, instead of 



