No. 7.] NIMEAVIDiE AND CANID^ OF THE MIOCENE PERIOD. 167 



tinguished from the true Felidce, and, as it appears to me, as a distinct 

 family. Should we ignore the characters adduced in this instance, we 

 abandon at the same time the definitions of several of the other families 

 of the order, and in fact throw the system into confusion. I have pro- 

 posed to call this family the Nimravidce, and have contrasted it with the 

 Felidce in the following definition. Both are included in the division 

 already defined on a preceding page. 



No distinct carotid foramen nor alisphenoid canal ; condylar foramen 

 entering the foramen lacerum posterius. No postparietal and gen- 

 erally no postgleuoid foramina Felidce. 



Carotid and condylar foramina entirely distinct from the foramen 

 lacerum posturius; an alisphenoid canal, and postglenoid and post- 

 parietal foramina Nimrmidm. 



NIMRAVID^. 



The dental characters of thQ Nimravidce are in general, those of the 

 Felidce, the higher genera having the same dental formiila. Descending 

 the scale, the number of molar teeth increases at both ends of the series 

 in the lower jaw, and anteriorly only in the upper, but the number of 

 the true molars never exceeds J. The following table gives the defini- 

 tions of the genera. I am unfortunately ignorant of the characters of the 

 foramina in Frocelurus and Pseudcelurus, as well as in JElurogale and 

 Eusmilus. 



I. Lateral and anterior faces of mandible continuous ; no inferior flange, 



a. Inferior sectorial with a heel ; canines smooth. 



Molars | ^ j inferior sectorial with interior tubercle Frocelurus. 



Molars f x j inferior sectorial without interior tubercle Fseudcelurus. 



II. Lateral and anterior faces of mandible separated by a vertical angle ; no inferior 



flange ; incisors obspatulate. 

 a. No anterior basal lobe of superior sectorial ; inferior sectorial with a heel 



(and no internal tubercle) ; incisors truncate. 



Molars f ^ ; canine smooth ArchoBlurus. 



Molars | \ ; canine denticulate Mlurogale. 



Molars | ^ ; canine denticulate Nimravus. 



III. Lateral and anterior faces of mandible separated by a vertical angle; an inferior 



flange ; incisors conic ; canines denticulate.* 

 a. No anterior basal lobe of superior sectorial ; t inferior sectorial with a heel ; no 



posterior lobes of the crowns of the premolars. 



Molars f ^ Diniciis. 



Molars f i Pogonodon. 



Molars ^ -\ Hoploplioneiis. 



Molars \\ Eusmilus. 



It is readily perceived that the genera above enumerated form an 

 unusually simple series, representing stages in the following modifica- 

 tions of parts : (1) In the reduced number of molar teeth; (2) in the 



* Gervais's figures of the canines of Eusmilus bidentatus represent no denticulations, 

 but the figure is not clear. 



t Eudimental in Hoplo^lwneus. 



