544 OREODON OF NEBRASKA. 
The latter remain separated throughout life, and relatively to those of most 
recent Ruminants, are very short. 
The nasal bones are of nearly uniform breadth, and posteriorly are received in a 
deep angular notch of the frontals. 
The palate plates of the palate bones advance as far as a line transverse to the 
first true molars, or even a little anterior to them. 
The intermaxillary bone is very much shorter than that of existing Ruminants, 
or even that of Carnivora, to which it has a strong resemblance at its lower part. 
Its process upwards is short, and is received by the apex into a notch of the supe- 
rior maxillary bone, and, so far as can be ascertained in the specimens, does not 
come in contact with the nasal bone. 
Inferior maxilla.—(Tab. x., fig. 5.) The lower jaw of Oreodon resembles more 
that of the Hog in its general form than of any of the existing Ruminants, excepting 
that the canine and incisive alveoli retain an upward direction like the molars. 
The body of the lower jaw is relatively deeper than in the Deer, and its base is 
more nearly straight. Its outer side is vertical, and very slightly convex. Ante- 
rior to the mental foramen, which is placed just below the second premolar, or the 
interval between it and the first, it rapidly converges to the symphysis. The latter 
is deep, and forms a strong slope, but approaches the vertical line even more than 
in the Hog. 
The alveolar margin ascends so rapidly posterior to the fourth premolar, that the 
body of the jaw behind the last true molar is more than half as deep again as it is 
below the former tooth. 
The ramus is very broad, and vertical externally. At its upper part, below the 
post-coronoid notch, it is deeply depressed relatively to the condition of the same 
part in existing Ruminants. 
The posterior margin of the lower jaw, a short distance below the condyle, in 
conjunction with the angle and bottom of the ramus forms a thick, strong convexity, 
prominent backwards and downwards, and also elevated externally for the attach- 
ment of the masseter muscle. 
The coronoid process is almost as short as in the Hog, and the condyle has the 
same relative position to its base as in the latter animal. 
Dentition.—The formula of the permanent dentition of Oreodon is,—in. *, can. ip 
premol. **, mol. 35, = 44. 
The superior molar teeth (Tab. x., 4,5; xi., 2, 3) on each side, internally, are 
nearly parallel. They form a continuous row, and are separated from the canines 
by a hiatus, not greater than the antero-posterior diameter of the first premolar, for 
accommodating the inferior canine. 
Laterally the superior incisors are in contact with the canines, but in some cases 
are separated by a slight hiatus. They project vertically downwards, and are 
arranged in the tangent of a considerably greater circle than that of the Wolf. 
The inferior molars are also very nearly parallel on both sides. They form a 
continuous row, with the canine included. Anterior to the latter, between it and 
the incisors, is a hiatus for accommodating the superior canine, but less in size even 
than that behind the last-mentioned tooth. 
