ARCH HOTHERIUM OF NEBRASKA. 561 
suture, resembles the cat tribe, and more particularly the extinct genus Machairo- 
dus; while the vertical orbits are separated from the temporal fosse by post-orbital 
arches, relatively as strong as in the Ruminants. The face posterior to the penul- 
timate premolar is demi-cylindrical, and constructed very much like the corre- 
sponding portion of the head of Choeropsis. The specimen indicates an animal a 
little larger than the Choeropotamus parisiensis, Cuv. 
Lateral view.—(Tab. x. 2.)\—The temporal fossa has about the same length as 
the depth, and extends antero-posteriorly from the lateral margin of the inion to 
the posterior margin of the orbit, and in this direction measures in a straight line 
about the middle five inches. The breadth is relatively as great as in Felis or 
Machairodus, measuring from the upper edge of the zygomatic process two inches 
seven lines. The temporal surface from above downwards is convex, and about a 
third of its extent is contributed by the frontal bone. The Squamous portion of 
the temporal bone is relatively small, appearing as if it was extended outwards to 
form the broad deep root of the zygomatic process, which, as in Sus and Dicotyles, 
originates on a line with the lateral border of the inion. 
The squamous suture descends in an irregular convex line in an unusually abrupt 
manner, and the coronal suture after passing obliquely backwards and downwards 
upon the temporal surface for a little over an inch, then descends vertically an inch 
and a half posterior to the anterior margin of the temporal fossa. 
The parietal bone has a remarkably broad descending process to join the sphenoid. 
The outer margin of the zygoma posteriorly is broken in the specimen. The 
portion of the process which turns forward to join the malar bone, is about three- 
fourths of an inch deep, and curves upward. 
The glenoid cavity appears to hold the same relative position as in the Peccary, 
but this, as well as the entire base of the cranium, is still enveloped in a hard 
matrix. 
The meatus auditorius externus and its process, also obscured by matrix, appears 
to hold a position at the bottom of a deep fossa posterior to the glenoid articulation. 
The orbital entrance is vertically oval, and is directed outwards and as much 
forwards as in the Cats, but not at all upwards. It is broader below than above, 
and its supra orbital margin is prominent outwards. Internally or anteriorly its 
margin presents a mammillary lachrymal process, above and below which it is 
notched. 
The malar bone advances upon the face as far forward as the lower part of the 
anterior border of the lachrymal bone. Its inferior margin ascends anteriorly, and 
below the orbit its external face is bent upwards, and is remarkably shallow, being 
at the narrowest part just in advance of the middle of the orbit only half an inch, 
and behind the orbit it is as remarkably deep, measuring from the summit of the 
post-orbitar process vertically two and one-third inches. : 
The face is long, broad, and demicylindroid in form, though it appears compara- 
tively narrow, with the great breadth of the cranium from zygoma to zygoma. The 
sides of the face are vertically convex, and the exit of the infra-orbitar canal is a 
large oval foramen, advancing upon a pian ms large depressed portion of 
