244 9. C. Marsh—New Tertiary Mammais. 
Antero-posterior diameter of upper incisor, ---- ---- ---- 25° 
PERRIN YOTBR CIDIROUOR ooo iis = Siw kw bs bo ewiny 11° 
Antero-posterior diameter of first lower premolar, ---. -- 24° 
NR SERN a eens Sem ys 14 
ntero-posterior diameter of second premolar, - - -- - - ---- 26 
TR PUATT ONES Un ie aco oa eis a's 18 
The geological horizon and locality are essentially the same 
as in the last species. 
Diceratherium advenum, sp. nov. 
lower molar has a high narrow crown. e enamel is rugosely 
striate. 
Measurements. 
Greatest antero-posterior diameter of last upper molar,.._ 40°” 
Transverse diameter (approximate), .... ....--------- 42° 
ion Ot ARRON WROy oS ae oe 19° 
Antero-posterior diameter of last lower molar, ---- ----- 40° 
aeeunwere Guinean ip Piles 19 
Height of unworn posterior crest, ...........-..------ 22 
The known remains of this species pertained to an animal 
half the bulk of the Indian Rhinoceros. The main interest 
attached to them is the fact that they were found with Ae 
Eocene fossils, in Utah, and are the first indications of tbls 
group in that region. Possibly the strata containing these 
fossils may in part prove to be lower Miocene. 
_ the former as the Lower Eocene representative or ancestor of 
the latter group. The skull and teeth of Hyrachyus are 8° 
similar to potas of Hyracodon that only slight changes are neces 
sary to transform one into the other. The skeletons, too, are 
. 
much alike, bat Hyracodon has only a rudiment of the fifth 
