242 COPE: [Vor TH: 
triangle of the tuberculo-sectorial type, but with the anterior 
limb rudimental. The posterior part of the crown differs from 
that of the Coryphodontide in having no posterior transverse 
crest, but in its stead the diagonal crest which connects the 
external extremity of the posterior transverse with the interior 
extremity of the anterior transverse crest. This oblique crest 
wears the posterior crest of the superior molars on its anterior 
face, as the anterior transverse 
crest wears the anterior crest (cin- 
gular) of the superior molar on its 
anterior face (Fig. 67). 
Comparison with the dental 
structure of Pantolambda (Fig. 
62) shows which crests of the 
two series stand in this relation to 
each other. The diagonal crest 
of the inferior molar in this genus 
shears in front of the posterior limb 
Figure 66. — Dinocerata, teeth, of the anterior V of the superior 
bre tous nat. ee Upper. HULGS molar. Guided by this fact we 
superior molars of Uintatherium Let- ; 
dianum, one-fourth nat. size. Lower may regard the posterior Cross- 
figure, inferior molars of jaw of an- crest of the superior molar of the 
other species of Uintatherium. From Ujntatheriide, as the posterior 
1 ah all and Jimb of the anterior external V. 
We must then suppose that the 
anterior limb of this V has disappeared from this type of 
molar, and the anterior cingular crest has taken its place, thus 
forming a long V with the posterior limb. The tubercle 
between the crests at their open external valley, may be a 
remnant of this external crest. A low tubercle on the crown 
behind the inner extremity of the posterior crest may be a 
rudimental fourth tubercle (hypocone), or even the apex of the 
posterior external V. 
The homology of the posterior crest of the superior molar 
here proposed, is sustained by the fact that there is no posterior 
transverse crest on the lower molar.!_ Had the crest in ques- 
tion been part of the posterior V of the superior molar, the pos- 
terior crest of the inferior molar would have had use, and would 
not have disappeared. 
1 The raised heel on these inferior molars is not the posterior transverse crest. 
