Pe fe 
Cope.] 566 (Jan. 18, 
Measurements. M. 
Width of skull between last upper molars, inclusive... .070 
Depth of occiput to foramen MagnUM....+....+eeeeee 048 
Peay ee uM f DaBLOCCIPITAl: DOME yeh» u's ete ODS 
‘« ¢ gkull at last superior molar, exclusive........ .058 
Fett ek CCS Tat, DTEMOlTs: CXGUIBLY.C' Vibra. bie: «i tcv,et 055 
fe  O VAMUS MANGO Ab ALO OL Dl Whee» resis .035 
IO ath ih by ih POOMP MMLC) oo a ue eee hg oO), 
‘« «© zygomatic arch above glenoid facet............027 
Diameters of base of crown § anteroposterior.......... .009 
of superior canine COPAMBVCREG, hale ci yy ve 0085 
Length of superior diastema.....sessseseceasrsererne 022 
EE DPOMOIAT BETICB, 6 by shvwiis sae vpn e'e i valk ukbagen Oe 
ff EAMG TOLAT SETIOR) dere oeine sie apne yi cpinie.«, olnui are 043 
Width of premaxillary bones together...... He adi via (O45 
Diameters of base crown inferior P-m. i; anteropos- 
COTLOL sd cieivis wy ov si vieiewyivs,ei see y'ey ewe dw.o'e Fiat ier VOR 
Length inferior diastema........-cceseeeereeees dsr ey OLD 
hi i last three premolars.....serceccotrecs OGL 
ie e true molars....... COR, Ibe dante sca ohh UO 
si tie last true molar..... eal er vipe RNa wve Wass Ue 
ie ha THAN PIEMOLAT. 46 sins Sa ewe nee biplane 009 
ki i LOUWP Gin ce vine es Wah wy aio oss west (ia euntn cnile 
anteroposterior. .. .019 
Horizontal diameters of otic bulla § 
tUANBVOPSE se e00+ se OLE 
The specimens of this species which I have seen, are from the John Day 
river, and were obtained by Messrs. Sternberg, Wortman and Davis. The 
skull from which the above description was taken is the most perfect one 
of the genus Agriochoerus which has yet been found. 
Agriochoerus ryderanus Cope. 
Ooloreodon ryderanus Cope, Bulletin U. 8. Geological Survey Territo- 
ries, vi, p. 173. 
This species is represented in my collection by three nearly complete 
skulls without mandibular rami. While of the general size of the A. guyo- 
tianus, this species displays various well marked peculiarities. The most 
important of these are (1) the shape of the otic bulla, in which it differs 
from all other known Oreodontide ; (2), the position of the infraorbital 
foramen, in which it resembles in this genus only the A. trifrons ; (3), in 
the form of the nasal bones posteriorly, in which it differs from the species 
where this part is known; (4), in the form of the palatonareal border ; 
(5), in the form of the postglenoid process; (6), in the outline of the sec- 
tion of the frontal bone. 
Agriocharus ryderanus has the muzzle compressed laterally and flattened 
on top, as seen in the A. guyotianus and A. trifrons, and the side of the 
