1879.] NATURAL SCIENCES OF PHILADELPHIA. 169 



characters more fully than any other author. He points out the 

 fact that in some of the species the orbits are closed behind, 

 and in others open. He first examined into the manner of the 

 contraction and closing of the pupil in the presence of light, and 

 pointed out the fact that in the large cats it is always round and 

 approximates a point in closing, while in the smaller forms the 

 pupil closes as a vertical slit. He shows that the cats of the 

 former group have the smaller orbits of the cranium, and the lat- 

 ter the larger. Dr. Gray, however, uses other characteristics in 

 the discrimination of the genera, which are, in my estimation, 

 quite inadmissible; as the relative length of the muzzle and of 

 the premaxillary bones; also of the hair on different parts of the 

 body and tail. Such features of proportion are essential as 

 characters of species, but not of genera. In accordance with 

 these views, I have united several of Dr. Gray's divisions into 

 groups, which I call genera, and which repose on some definite 

 structural characters. Thus I combine his Uncia, Tigris, Leo and 

 Leopardus into a genus for which I employ his name Uncia, as the 

 least objectionable, 1 after having confirmed by autopsy the circu- 

 lar character of the pupil. This I was enabled to do through the 

 courtesy of my friend Arthur E. Brown, Superintendent of the 

 Philadelphia Zoological Garden, who aided me in examining the 

 eyes of these animals both by sunlight and the light of a bull's- 

 eye lantern.- The detailed characters of the genera will now be 

 given : 



I. The anterior and lateral faces of the mandible separated by 

 an angle. 



a. inferior sectorial with a heel ; no anterior lobe of supe- 

 rior sectorial ; no posterior lobes of the premolars. 

 * An inferior tubercular molar. 



Premolars . Dinictis. 



Premolars f. Nimraous. 



1 I assume that this name is derived from uncus, a hook, whicli is appro- 

 priate to the weapons of these animals. 



2 I add the following notes on some other Garnivora, which do not 

 come within the scope of this paper : 



Mymna crocuta. Pupils a vertical slit. 



Viverridce. Three species of Ichneumon and viverricula, a horizontal 

 oval. 



Nasua. A horizontal oval. 

 12 



