O. C. Marsh—New Tertiary Mammals. 247 
eride. From this family, tga differs widely in its 
jenkoae and the absence of 
The cervical vertebrae are on and opisthoccelous. The 
radius and ulna, and tibia and fibula, are distinct, and the feet 
In the present species, the incisors are all well developed, and 
those in the lower jaw are directed forward. The canines are 
s con 
nate. The upper true molars are surprisingly like thads of 
Brontotherium. 
Measurements. 
Extent of upper mone ROMO ccs kk 2420 
Extent of npper trae’ molars, ...-.- /.. 4.4.0-- 2 -- + ohn 152° 
Antero-posterior diameter of first upper premolar, ---- .-- 14° 
ial i bt: rood of second upper premolar, - --- - - 21° 
"Transverse .dinmpetets so. occ 35 Gos pa gs Se ce 
Antero-posterior ances of fourth upper premolar, .._. -- 28° 
Tpaneveree Crates a nh es ace 34° 
Antero-posterior diameter of first upper true molar, .. -- -- - 42° 
‘Transverse dismutase 57° 
Antero-posterior peliane of second SPP molar,........ 52° 
Transverse di 57° 
Antero-posterior diameter of last upper molar, Cinna cuyee 60- 
Transverse diam GAR yg gue sags Sa ew ee ee 
Width of palate eewses posterior GaN ce 92° 
Distance between bases of canines of lower jaw 2dspecimen) 46° 
Antero-posterior wpa Rigg eter of canine, at bas 32° 
Transverse di ici ees iwec een case ees 28 
Height of cro 27 
Antero-posterior diameter of first lower PreMOlMar, .... 5... Lz 
Transverse diameter, ------ 10° 
Aateropomacies diameter of second protagiar, 2500. 26° 
Transverse diameter, in front,_--- 15° 
Antec pekindon diameter of third premolar, (5 i055 28° 
Transverse diameter, in front, _--- artis Whe 
sank ery diameter, pretenionly, iors ae 
Length of median cervical yorlebra,. oo = <5 o6 2444 --b ee 45° 
Transverse diameter of anterior articular face, Gwe aes e 60° 
Venton! dinmeter:. o0 5. ois eas 63° 
The remains here described belonged to an animal weet Es 
mh as a rhinoceros. They are from the Upper Eocene 
of Utah. 
Orohippus Uintensis, sp. nov. 
The present species is the largest of the genus, and in some 
popes indicates a transition between the lower Eocene species 
and the allied forms in the Miocene. It agrees with the known 
