PETERSON: A REVISION OF THE ENTELODONTIDA 81 
diameter. There isa heavy cingulum on the posterior face which extends half way 
around the base of the lingual side. Ig is nearly twice as large as the tooth just 
described, but otherwise the two are quite similar. On the external faces of Ig and 
ly are deep grooves across the faces, just below the enamel band, which were not 
caused by the wear of the upper teeth. Inasmuch as the canines of both sides have 
a similar and much greater worn area externally, which could not have been reached 
by any of the upper teeth, it further supports the contention of Professor W. B. Scott 
and C. F. Brackett, that these animals used the lower tusks in digging in the ground 
for roots (87, footnote, p. 275). They may also have been used for stripping off the 
foliage of shrubbery. ‘There is a slightly developed cingulum on the posterior face 
of the canine, otherwise the enamel is quite smooth. The crown is higher and more 
pointed than that of the upper canine, but in general appearance and size it differs 
little from that tooth.” 
P+ is separated from the canine by a short diastema; the tooth is implanted in 
the jaw by two strong fangs which coalesce for some distance below the crown. The 
latter is simple and is rather low when compared with that of Archxotheriwm. On 
the internal face the enamel is crinkled, but externally the tooth is quite smooth. 
Posteriorly there is a heavy cingulum and anteriorly there is a prominent oblique 
ridge, which originates at the antero-internal angle and continues outward and 
upward to the apex, constantly diminishing in prominence in its upward course. 
The apex of the crown in the type is considerably worn, but it is quite easy to ascer- 
tain its contour which was very much more obtuse than in Archxotheriwm. There 
is a considerable diastema between Pz and Py. The latter is also implanted with 
two roots which are, however, more divergent and do not coalesce below the crown 
asin Pz. The crown of Py is of about the same size as the crown of the preceding 
tooth, but its apex is less worn and there is a mammillated ridge on the anterior and 
posterior faces of the protoconid. There are prominent anterior and posterior 
cingula and the enamel on the internal face is thrown into light folds, while the 
buccal face of the tooth is smooth. Py is, as usual, the largest in the series; it is 
not crowded in the alveolar border, but is separated from Pz by a very short dia- 
stema. The apex of the crown is next highest to that of the canine and in general 
form it is not unlike that of Py. Pz has a heavy heel which agrees in general with 
Pz in Mntelodon magnum. Altogether Pz of the present genus presents a different 
outline from that of the corresponding tooth in the earlier genera, which fact is 
wholly due to the increased transverse diameter of the tooth posteriorly. 
*1The left lower canine is disproportionately short and stubby and was evidently broken off at the apex during 
the life of the animal. 
