1895.] Geology and Paleontology. 1091 
Discovery, in the Oligocene of South Dakota, of Eus- 
milus, a Genus of Sabre-toothed Cats New to North Amer- 
ica.—In 18738, Filhol® described and figured under the name of 
Machaerodus bidentatus, portions of the mandibles and superior canines 
of a sabre-toothed cat from the phosphorites of Quercy. Two years 
later, Gervais’ described similar remains from the same beds under the 
name of Eusmilus perarmatus. There seems to be little doubt that E. 
perarmatus is identical with M. bidentatus; but since the material 
shows characters which at once distinguish it from the genus Mache- 
rodus, Cope has accepted the genus Eusmilus, proposed by Gervais, 
and retained Filhol’s specific name. Eusmilus bidentatus may then be 
considered to include all the known remains of this remarkable feline. 
Hitherto no American representative of this genus has been reported. 
In 1894 the writer had the good fortune to discover in the Protoceras 
beds of the upper White River ( Oligocene) deposits a complete ramus 
which agrees fully in all the generic characters known to Eusmilus, and 
is of interest as being the first American representative of that genus. It 
differs, however, from the European species in several important char- 
acters, and may be called E. dakotensis. 
Eusmilus dakotensis sp. nov. 
The type of Eusmilus dakotensis consists of a right ramus (No. 11079, 
Prine. Coll.). It isin a splendid state of preservation, and all the 
teeth except the canine are entire. Most of the characters are well 
shown in plate XL, accompanying this paper, which has been produced 
from very accurate drawings of the specimen made and placed at my 
disposal through tlie kindness of Mr. Rudolph Weber. 
Dentition :—I x, C. 1, Pm. z, M.x. . The incisors are recurved, about’ 
equal in size, and have rather sharp lateral edges. The crown of the 
canine is gone, but the root of this tooth indicates that it was rather 
weak, the antero-posterior diameter is about twice the transverse. The 
alveolar border between the canine and pm. , consists of a sharp ridge 
of bone; it is complete, and demonstrates conclusively the absence of 
pms. x,2,,- Premolar; is well-developed and fixed in the jaw by two 
roots ; it is directed upward and backward. The protoconid is high 
and sharp, the paraconid and metaconid are much smaller and about 
equal in size, the former has a somewhat internal position and is out 
of line with the other two cusps. There is only a faint indication of a 
basal cingulum. The sectorial is quite simple, consisting only of a 
ë Bull. Soc. Phys. et Nat.. Toulouse, 1873, t. I, p. 205. 
* Journal de Zoologie, 1875, t. XVIII, p. 419.. 
