PETERSON: NEW SULLINE REMAINS FROM THE MIOCENE OF NEBRASKA 307 
been discarded in the process of modification. P, is separated from p, by a short 
diastema, and the tooth had two roots. Pgs indicates a tooth with a compressed 
simple crown. There is a considerable posterior heel and a slight cingulum on the 
antero-internal face of the tooth. P, has two main cusps, proto- and deuteroconids, 
well appressed, forming a cross-crest anterior to the middle of the crown, as in 
Fie. 1. Oblique internal view of left mandible of specimen No. 913, Carnegie Mus. Cat. Vert. Fossils 
3 nat. size. 
Fia. 2. External view of left lower mandible of specimen No. 913, Carnegie Mus. Cat. Vert. Fossils. 4 nat. 
VA 
Cope’s description of Bothrolabis trichenus. Anteriorly on this tooth there is also a 
small basal cusp and the cingulum on the postero-exterior angle of the tooth is 
thrown into a short fold forming a minute tubercle. The elevated ridge on the 
posterior heel, the metaconid, is perhaps more in the middle longi- 
tudinal line than, according to Cope, seems to be the case in his 
Bothrolabis trichenus. M, isa much worn tooth; the wear of the 
triturating face, however, indicates the usual quadri-tubercular 
style of tooth. The antero-posterior diameter is but slightly greater 
than that of P,. The anterior half of m, is damaged internally 
and externally. The hypo- and entoconids are well separated on 
the broad grinding face, and just back of these, at the posterior 
border of the tooth, there is a small median cusp, the hypoconu- 
I a >) 
IL lid. In the valley between the anterior and posterior cusps is a 
é swelling of the worn surface which indicates a small median conu- 
Fig. 3. Superior j- 6 F 3 E z 0 
5 lid. On the internal margin opposite to this cusp is a basal pillar 
view of left lower 
mandible of specimen Which fills up the bottom of the transverse valley. No other 
No. 913, Carnegie evidence of a cingulum is present on the tooth. The antero-pos- 
Mus. Cat. Vert. Fos- 
: : terior diameter of m, is slightly greater than that of m,. The 
sils. 4 nat. size. q 
increase of the antero-posterior diameter of all the teeth is very 
gradual, as p. isonly 5mm. shorter than m,. Ms corresponds to that of Bothrolabis 
trichenus which Cope described as haying “two pairs of cusps and a large heel.” 
The paraconid can also be outlined on the tooth near the anterior cingulum. ‘This 
