AS 
Cope.) 542 (Jan, 18, 
Measurements. M. 
No. 1. 
Disniererecaita: HILSLODOSUGDIOL s veny iiriy bisctlepiin by ¥8 Ane ng tit) 
transverse..... pia Sia a: areas ae A ie ishe O15 
Length of inferior dental series (axial)........... Ae rvea (lh! 
" i premolar series (axial). ......... Dando 
Long diameter of crown of canine, ......5...00565 en eOOK 
by Py EM Me de sunk Wao vagitile dina akialhie Tate «2. .0086 
nt vs Se Prete Ap aisha gw ainey BN EIU ik AT PN etE 0084 
Tiarnaters Gatniane f QINVOPOPORTOLION is eit eva sinte ae ES .012 
UIPBHSVOTBG NO vices o's ve 009 
‘y < ss f anteroposterior,........ 0147 
cera da { PLGMIBVCCBOL Tend ire ao tune teks dy tce .010 
idm ekene act A AMTCLOPOBTCHION i iii ca ee sid) wees viv .URRO 
CAMEMBVORSG NE Cle b a emi Wdl tired pied eins Oni) 
The specimens all came from the Ticholeptus beds near Laramie Peak, 
Wyoming, and were discovered by my assistant, J. C, Isaac. 
Merychyus pariogonus, sp. nov. 
The generic position of this species is uncertain, and it may belong to 
Merycocheerus or even to Eucrotaphus, as its otic bulle are inflated. The 
doubt as to its position is due to the fact that the anterior part of the skull 
of the typical specimen is lost as far back as the anterior border of the 
orbit, and the second molar tooth. I place it here provisionally because 
the internal crescents of the superior molars are arranged as in JZ major 
and iM. arenarwm, ¢. e., with the anterior crescent excluding the posterior 
at the point of junction of the two. 
The Merychyus pariogonus is about the size of the Oreodon culbertsont. 
The braincase is full, so that the internal side of the temporal fossa is 
strongly convex, but without very prominent ridge along the pariéto- 
squamosal suture. The anterior temporal ridges unite at an acute angle, 
but the sagittal crest is obsolete as faras a point above the posttympanic 
process, where it gradually rises. The posterior temporal ridge is promi- 
nent superiorly, but is not produced beyond the line of the occipital 
condyles. It is discontinued in the direction of the supraauricular ridge, 
but continues downwards as an obtuse ridge on each side towards the 
foramen magnum. Between this and the squamoso-occipital angle is 
a large open fossa which is present in the species of this genus, of Mery- 
cochcerus and of Eucrotaphus, but is wanting in Oreodon culbertsont. In 
the obsolescence of the posterior temporal crest it agrees with the last 
named species, and with some of those of Merycocheerus, but differs from 
Hucrotaphus jacksoni where it is low, and from Merychyus leptorhynchus, 
where it is well developed. In the size of the lateral occipital fosse this 
species exceeds any of the others of this family. Below the depression, 
the posterior temporal crest rises abruptly, forming a convex edge which 
continues downwards nearly obsolete, on the suture between the post- 
