948 THE MIOCENE FAUNA. 



molars never exceeds ^. The following table gives the definitions of the 

 genera. I unfortunately do not know the foramina in Pseudcelurus. I in- 

 troduce Procelurus for comparison, although as I have pointed out/ it is a 

 member of the Cryptoproctidce. I do this the more readily as it is quite 

 possible that when the number of the digits of some of the species now in- 

 cluded under the Nimravidce comes to be known that they may prove to 

 have them five on both feet, and hence to be members of the Cryptoprodidoe. 



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



fl. Inferior sectorial with a heel ; canines smooth. 



Molars ji ; inferior sectorial with interior tubercle Prowlurus^ 



Molars f^ ; inferior sectorial without interior tubercle Psetidcelurus. 



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 ^i; canine smooth Archcehirus, 



Molars |^; canine denticulate JEhirogale. 



Molars fi; canine denticulate Nimravus. 



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



flange ; incisors conic ; canines denticulate.^ 

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



posterior lobes of the crowns of the premolars. 



Molars |i Dinictis. 



Molars fx PiHionodon. 



Molars ?^ ^ - • HopJophoncus.^ 



Molars ^^ ... EusmUus. 



It is readily perceived that the genera above enumerated form an 

 unusually simple series, representing stages in the following modifications of 

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

 of the superior canine teeth ; (.H) in the diminished size of the inferior canine 

 teeth ; (4) in the conic form of the crowns of the incisors ; (5) in the addi- 

 tion of a cutting lobe to the anterior base of the superior sectorial tooth ; (6) 

 in the obliteration of the inner tubercle of the lower sectorial, and (7) in the 

 extinction of the heel of the same ; (8) in the development of an inferior 



'American Naturalist 1881, p. 339. rroalurus b.as also beeu shown by M. Filhol to be one of the 

 Cryptoproctidm. It is also iinccrtaiu whether Pseiidaliinis lielongs to the Ximravida-. 



" Gervais' figures of the cauines of Eusmilus bidcntalits represent no deuticulations, but the figure la- 

 not clear. 



'Rudimental in Hoplophoneus. 



