EXTINCT CATS. 287 
the last molar being small and oval. In the limbs the femur 
has a third trochanter ; the five-toed hind-feet were probably 
plantigrade, and present considerable resemblances to those of 
the primitive Civets and Dogs, while the claws were retractile. 
The genus is exclusively North American, and is represented 
by some three species from the Miocene strata of Nebraska, 
Colorado, and Oregon, its typical member being Dvrnictis 
felina, which appears to have been an animal of the approxi- 
mate dimensions of a Lynx. 
Of D. cyclops Professor Cope remarks that “although of an 
inferior position in the system of Carnivora, its powers of de- 
struction must have excelled those of the Catamount [Lynx]. 
While the skull is generally less robust, its sectorial teeth are 
not smaller nor less effective than those of that animal, and the 
canines far excel those of the living species, as instruments 
for cutting their prey.” 
VII. GENUS NIMRAVUS. 
NNimravus, Cope, Proc. Acad. Philad. 1879, p. 169 ; id., Amer. 
Naturalist, vol. xiv. p. 842 (1880). 
Nearly allied to the last, this genus, which is likewise North 
American, forms an exception to the present group in that 
there are only two pairs of pre-molar teeth in the lower jaw. 
In the upper jaw the first pre-molar is minute, and the molar 
transversely elongated ; while in the lower jaw the carnassia] 
tooth is devoid of an inner cusp, and the second molar very 
small. The femur has no third trochanter. While the pre- 
ceding genus is most common in the Lower Miocene White 
River beds, the present one is confined to the overlying Upper 
Miocene John Day beds of Oregon, where it is represented by 
LV. gomphodus and LN. confertus, both of which may be compared 
insize toa Leopard. Inall the points in which the genus differs 
from Dinictis, it approximates to the modern Cats: precisely 
as might have been expected from the higher geological hori- 
zon in which its remains occur, 
