286 LLOYDS NATURAL HISTORY. 



the structure of the base of the skull by which these primitive 

 Cats differ from their modern allies, one of these being the 

 presence of an alisphenoid canal. There is also a difference 

 in the structure of the astragalus bone of the ankle, while many 

 of these extinct Cats have a third trochanter to the femur, or 

 thigh-bone. 



On account of these structural distinctions, these primitive 

 Cats have been referred to a distinct Family, the Nimravida ; 

 but in the structure of the lower carnassial tooth, as well as in 

 some other features, they are clearly connected by means of 

 Eusmilus and Machcerodus palmidens with the more typical 

 representatives of the latter genus, and it is thus evident that 

 the whole assemblage forms but a single family group. 



The genus /Elurictis, as represented by sE. intermedia and 

 two other species from the Upper Eocene of France and Wiirt- 

 temberg, has large upper canines, a small two-rooted anterior 

 upper pre-molar, a small rounded upper molar inserted by two 

 roots, a very small and single-rooted anterior lower pre-molar, 

 and the lower molar (which may be wanting) also small and 

 implanted in the jaw by a single root. Only fragments of the 

 skull, which in the case of the type species indicate an animal 

 nearly as large as a Leopard, are known. 



VI. GENUS DINICTIS. 



Dinictis, Leidy, Proc. Acad. Philad. 1854, p. 127 ; Scott, Proc. 



Amer. Phil. Soc. 1889, p. 211. 

 Daptophilus, Cope, Rep. U.S. Geol. Survey for 1873, p. 50S 



(i374). 

 In this genus the skull is characterised by its short, vaulted, 

 and generally Cat-like form, the first upper pre-molar being 

 very minute and single-rooted, and the last molar transversely 

 elongated, and inserted by three roots. In the lower jaw the 

 first pre-molar is minute ; and the carnassial differs from that 

 of ALlurictis in having a cusp on the inner side of the blade, 



