540 Gencral Notes. [July, 
GEOLOGY AND PALAONTOLOGY. 
A New Genus OF RHINOCERONTIDA.—While the genus Aphe- 
lops must be regarded as the direct ancestor of the recent rhino- 
ceroses with canine and incisor teeth, now confined to Asia and 
the Islands; the ancestral genus of the African forms and their 
extinct congeners, which are without the teeth named, is less 
, n now be shown that the missing genus inhabited 
North America, and that like Aphe/ops, it is hornless. It may be 
named and characterized as' follows: Peraceras Cope; superior 
dentition; I. 0; C. o; P-m.4; M.3; nasal bones weak, hom- 
less, 
_ This genus is established on a new species recently discovered 
by Mr. R. H. Hazard, in the Loup Fork formation of Nebraska, 
which may be called Feraceras superciliosus. It is founded ona 
nearly perfect skull, which lacks the lower jaw. Its size is about 
that of the Indian rhinoceros. It is narrowed anteriorly, but is 
very wide between the orbits. Posterior to these it contracts 
rapidly, and rises to a rather elevated occiput. Saggital crest 
narrow; a prominent angle above each orbit. The premaxillary 
bone is narrow and weak. The nasal notch extends to above the 
middle of the third superior premolar. The occiput is rectangular 
in outline, with truncate summit. Its surface above is concave, 
divided by a strong median crest; lower down a vertical groove 
intersects its lateral border. The crests of the molar teeth are 
rather simple, and the posterior notch is soon isolated on attri- 
tio ear also isolates an external median fossa of the second 
remolar. Length of skull from end of premaxillary bone to 
condyles, M. 700; length of alveolar border of premaxillary, 
.025; length of molar series, .315; length of three true molars, 
.160; width of crown of second true molar at base, .075 ; super- 
ciliary width, .255. 
This species is nearest to the Peraceras malacorhinus, a species 
| doubt belongs to the present genus. It differs from /. super- 
ciliosus as follows: In the latter species the front is wider, and 15 
crest not found in P. malacorhinus, and has the vertical lateral 
grooves much shorter. e acute supraorbital angle is not seen 
in the P. malacorhinus. : 
The rhinoceroses of the Loup Fork formation whose generic 
position can now be ascertained, are the following: Paraceras 
malacoriinus ; P. superciliosus; Aphelops meridianus ; A, mega- 
lodus ; A. fossiger—E., D. Cope. 
