with Descriptions of New Genera and Species. 103 



by William Day in 1876, is Cat. No. 12426, Y. P. M., and 

 was enclosed in the typical green matrix of the middle 

 John Day. The superior premolars in both holo- and 

 paratype are crowded, and the nasals extend to a point 

 above the incisor border. 



Measurements of Holotype. 



mm. 



Length, occip. condyles to prosthion, inc 169 



Superior molar series, length 38 



Superior premolar series, length 34.5 



Max. diameter, postorbital constriction 35 



Eporeodon longifrons (Cope) 1884. 



Holotype, No. 7504, Cope Coll., A. M. N. H. Upper Oligocene (upper 

 John Day), North Fork, John Day Eiver, Oregon. 



Specific characters. — Skull large and robust ; lacrymal 

 fossa moderately deep and well defined; short sagittal 

 crest ; cranium and postorbital constriction wide ; infra- 

 orbital foramen above posterior part of P^ ; greatest 

 bizygomatic diameter anterior to glenoid process ; pos- 

 terior part of nasal bones pointed and extending to ante- 

 rior margin of orbits ; posterior nares round, and palate 

 moderately produced beyond M^. 



This species was not common, if we may judge from 

 the number in the Marsh Collection. Specimens were 

 collected under the direction of Professor Marsh on the 

 North Fork of John Day River (type locality), at 

 Haystack Valley, 5 or 6 miles below Cottonwood, and at 

 Turtle Cove. 



Measurements of Holotype. 



mm. 



Total length of skull 255 



Superior molar series, length 47 



Superior premolar series, length 47 



Superior dental series, with canine, length 118 



Diameter, postorbital constriction 47 



Eporeodon major (Leidy) 1854. 



A fragmentary muzzle with complete and well pre- 

 served molar series, together with P^ and P^, Cat. No. 

 12400, Y. P. M., is referred to E. major. It coincides with 

 Leidy 's description of the type in so far as it is possible to 

 determine. The Yale specimen, the only one of thi^ 



