_Lower Jaw._--The ramus is stout, and resembles in general form
that of _Hyrachyus_, but the alveolar border is straighter than
in that genus; the ascending portion forms a right angle with the
horizontal portion, and the masseteric fossa is deep. The symphysis
is comparatively short, and there is complete bony union between
the rami, which do not diverge so much as in _Hyrachyus_. As in
that genus, there are several small mental foramina beneath the
premolar series. The dental series forms a nearly continuous line,
the only diastema being a very short one between the first and
second premolars. The _incisors_ have compressed fangs, and are
arranged in a slight curve. The canine is small and subcircular at
base. The _premolars_ also are small; they somewhat resemble those
of _Hyrachyus_ in shape, but are smaller, and have the posterior
lobe not so well developed. The first is implanted by a single
fang, the others by two. The _molars_ (except the last) consist of
two pyramidal lobes, which form transverse cutting-crests, as in
_Tapirus_ and _Hyrachyus_. The basal ridge is shown on the anterior
and internal sides only. Externally the lobes meet at their bases,
inclosing the valley on that side. The last molar is by far the
longest of the series, and consists of three lobes, of which the
anterior is the largest, and the posterior the smallest. The basal
ridge at the anterior part of the tooth is very strongly marked.
_Upper Jaw._--The molars increase in size from first to last with
considerable regularity. The premolars are small, and, as in
_Hyrachyus_, have one single internal cone, which is joined by
transverse ridges from the two outer cusps; the anterior accessory
tubercle is well developed. The first molar is considerably larger
than the last premolar; it is much worn, and does not show anything
more than that there are two internal cones. The anterior conical
buttress is very largely developed throughout the true molar
series. The second and third molars resemble almost precisely the
corresponding teeth of _Hyrachyus_. Their shape, however, is more
nearly square than is usual in that genus.
_Measurements._
UPPER JAW.
M.
Length of true molar series ·036
Length of last molar ·0135
Width of last molar ·015
Length of second molar ·012
Breadth of second molar ·015
Length of first molar ·0105
Breadth of first molar ·012
Length of last premolar ·009
Breadth of last premolar ·011
Length of third premolar ·008
Breadth of third premolar ·009
LOWER JAW.
Length of true molar series ·042
Length of last molar ·018
Breadth of last molar ·009
Length of second molar ·013
Breadth of second molar ·008
Length of first molar ·012
Breadth of first molar ·008
Length of third premolar ·008
Breadth of third premolar ·005
Diameter of canine at base ·006
Length of symphysis (about) ·027
Found at Henry's Fork.