Pay 
1884.) 531 (Cope. 
Measurements. M. 
anteroposterior. ....... seeeeee: O44 
C thansverses! ii cveatdiy. Wiles OUD 
This fine species is from the John Day epoch of the Miocene. The 
typical specimen was found by my assistant, Charles H. Sternberg, on 
Bridge creek, Oregon. Much credit is due Mr. Sternberg for his unwearied 
exertions in the cause of science, which have been continued through 
many occasions of risk and discomfort. 
Diameters inferior m. iii 
Merycochoerus montanus, sp. nov. 
This large animal is represented in: my collection by a nearly entire 
skull with parts of both mandibular rami complete. Rami of another in. 
dividual give the entire dentition of the lower jaw except the incisors, 
A third individual is represented by a symphysis with premolars, ca- 
nines and incisors, and by various parts of the skeleton, including feet. 
Of the cranium mentioned, the muzzle to the preorbital fossa and the 
palate to the first true molar are wanting. The region of the larmier is 
lost, but the general resemblance of the species to the J macrostegus in 
other respects, leads me to suspect that it is absent, and that the J. mon- 
tanus, is rightly referred to the genus Merycocherus. This course is indi- 
cated by the structure of the superior molar teeth, which have the character 
of those of this genus, rather than that, found in Merychyus. That is, the 
posterior internal crescent sends its anterior horn to the external wall of 
the crown, thus cutting off the posterior horn of the anterior crescent. 
Dr. Leidy has shown that the reverse is the case in the Merychyus major ; 
that is that the posterior horn of the anterior crescent, reaches the external 
wall of the crown, cutting off the anterior horn of the posterior crescent. 
Ihave observed that this is also the case in the other species of Merychyus 
which have come under my notice. 
The posterior position of the infraorbital foramen and the greatly pro- 
duced palate distinguish this species from those of the John Day epoch, 
excepting the M. macrostegus, while in the WM. rusticus and M. proprius, 
the infraorbital foramen is still further posterior. The palate of these 
species is unfortunately unknown. 
The part of the maxillary bone posterior to the infraorbital foramen is 
nearly flat, and the proximal part of the malar bone is also flat. The in- 
ferior edge of the latter is narrow and is marked by a groove which ter-, 
minates anteriorly in a shallow fossa. The ridge continuous with this edge 
terminates above the anterior lobe of the second true molar. The zygoma 
as far as the anterior border of the glenoid cavity is slender, and not con- 
vex, but flat in every direction, nor is it decurved as in MZ. superdbus. The 
zygomatic foramen is relatively much smaller than in that species. Its 
posterior or preglenoid boundary is not at right angles to the sagittal crest 
as in that species, but is oblique outwards and forwards at an open angle. 
The obtuse median edge of the zygoma looks upwards, not outwards as it 
does in M. superbus and M. macrostegus, and the superior expansion is 
