1885.] The Amblypoda. 53 
view both forward and backward, so that this beast probably 
resembled the rhinoceros in the ease with which it might have 
been avoided when in pursuit. 
The genus Uintatherium Leidy, has the symphysis of the man- 
dible more contracted than in the other genera, and the number 
of its teeth correspondingly reduced.! The type is the U. robus- 
tum Leidy, a species which is known from the posterior part of a 
skull with a few molar teeth of both jaws, and a superior canine 
tooth of one individual ; and by the greater part of the lower jaw 
of another. Itis of smaller size than those referred to Loxolo- 
phodon, and also smaller than the U. Zeidianum Osb. (Fig. 27). 
Besides these two species four others have been described by 
Marsh and referred to a genus Dinoceras, which is not yet known 
to be distinct from Uintatherium. The best known of these is 
the U. mirabile (Figs. 25, 26, 33), which has been well figured by 
Marsh. It lacks a tubercle of the last superior molar which is 
present in the Ọ. robustum. Its lower jaw is unfortunately un- 
known. A species described by Marsh as Dinoceras laticeps is of 
larger size than the D. robustum, and Marsh figures its lower jaw 
(Fig. 34). It possesses four teeth on each side of the symphysis, 
as in Loxolophodon, but their form is not known. There is a 
deep flange of the lower edge of the ramus below the canine 
teeth, as in Uintatherium. As this form represents a genus clearly 
distinct from either of these, or Bathyopsis, I propose that it be 
called Octotomus. To this genus may belong some of the spe- 
cies now provisionally referred to Uintatherium. 
In these animals the nasal tuberosities are small, and do not 
overhang the apex of the nasal bones. The median horns are 
anterior to the orbits, and are of various degrees of development 
in the different species. The posterior horns vary in like manner 
(compare Figs. 27 and 33). The supraoccipital crest extends 
much further posteriorly in the U. mirabile than in some of the 
other species. 
In the genus Bathyopsis Cope, not only the incisors and 
canines, but also the molars are of the full number, z. e., I. z; C- 
1; Pm. 4; M. This, with the posteriorly extended expansion 
of the ramus of the lower jaw, distinguishes it from the other 
genera. But one species is known, the B. jissidens Cope, which 
1See Cope, Proceeds. Academy Philadelphia, 1883, p- 295- _ 
