44 On the Genera of Felidae and Canidae. 



power of the lions and tigers of to-day. As nothing but the 

 characters of the canine teeth distinguishes these from the 

 typical felines, it is to these that we must look for the cause 

 of their failure to continue. Prof. Flower's suggestion ap- 

 pears to be a good one, viz. that the length of these teeth 

 became an inconvenience and a hindrance to their possessors. 

 I think there can be no doubt that the huge canines in the 

 Smilodons must have prevented the biting off of flesh from 

 large pieces, so as to greatly interfere with feeding and to 

 keep the animals in poor condition. The size of the canines 

 is such as to prevent their use as cutting instruments, ex- 

 cepting with the mouth closed ; for the latter could not have 

 been opened sufficiently to allow any object to enter it from 

 the front. Even were it opened so far as to allow the man- 

 dible to pass behind the apices of the canines, there would 

 appear to be some risk of the latter's becoming caught on the 

 point of one or the other canine, and forced to remain open, 

 causing early starvation. Such may have been the fate of 

 the fine individual of the S. neogceus, Lund, whose skull was 

 found in Brazil by Lund, and which is familiar to us through 

 the figures of De Blainville, &c. 



Description of New Species. 



Dinietis cy clops. 



The species of Dinietis differ in the proportions of their 

 anterior molar and canine teeth as follows : — 



First inferior molar one-rooted ; first superior molar 



two-rooted; superior canine short, robust; large. D. intermedia*. 



First inferior molar one-rooted ; superior caniue com- 

 pressed ; two inferior incisors D. squalidens. 



First inferior molar two -rooted ; first superior molar 



one-rooted ; canine long, compressed D. eyclopa. 



First molar of both jaws two-rooted; canine long, 



compressed D. felina. 



In D. cyclops the first superior molar is rudimental, and 

 will probably be found to be wanting in some specimens. 

 The second premolar has a distinct anterior tubercle on the 

 inner side, a character not seen in D. felina ; the anterior 

 angle of the superior sectorial is more produced than in that 

 species. The crown of the superior tubercular looks partly 

 inwards, is rather long, and has three roots. The superior 

 canine is quite long, and has a regularly lenticular sec- 

 tion, without facets ; its anterior and posterior edges are 

 denticulate. The external incisors are much larger than 

 the internal, and have subconic crowns. The crowns of the 



* ALhirogale intermedia, Filhol. 



