Dicerafheriam Proavitum. — Hatcher. 313 
DICERATHERIUM PROAVITUM. 
(Plate XIX.) 
« By J. B. Hatcher, Princeton University. 
In this journal for May, 1894, pp. 360-361, the writer de- 
scribed uirder the name of Diceratherinm proavitum. a mem- 
ber of the Rhinocerotid(H new to the White River formation. 
In my original description of this species I was unable to see 
the proof sheets and hence some typographical errors appear 
in tlie text, and in at least two instances erroneous characters 
are assigned to the type. It is the purpose of this brief paper 
to correct those errors in my original description and to give 
further reasons in favor of placing this form in the genus 
Dicerotheriani. rather than Aceratheriurn . 
The type consists of a nearly complete skull (No. 10965) 
of a fully adult, in fact rather aged, individual, without the 
lower jaw. The principal specitic characters are as follows : 
Skull rather short, low and broad especially in the region of 
the frontals; superior surface slightly concave antero-posteri- 
orly ; sagittal crest short, low and broad; strong postorbital 
processes on frontals; nasals very strong, partially coossified 
and bearing upon their upper and outer surfaces a pair of 
rugose prominences situated at about one-third the distance 
from their extremities to their junction with the frontals. 
These prominences resemble very much the rugosities sup- 
porting the nasal horns in many of the recent rhinoceroses, 
and doubtless served the same purpose in D. proavif.u)v. 
Behind this pair of rugosities the nasals are constricted, but 
posteriorly they expand again to meet the broad anterior 
border of the frontals. The fronto-nasal suture is but little 
in front of the orbit. In front of the pair of rugose eleva- 
tions the nasals contract rapidly and are directed down- 
ward and forward. The occipital crest is emarginate in the 
median line and overhangs the occipital condj^les. The 
zygomata are rather slender but stronger than in Acerofherivhi. 
occidentale. The post-tympanic and post-glenoid processes 
are in contact but not co-ossified. The anterior border of the 
posterior nares is situated just behind the posterior edge of 
the first molar. Of the teeth only the molars and premolars 
are preserved in the type and they are rather too much worn 
to determine accurately their characters. The first premolar 
