G. I. Adams — Extinct Felidce of Worth America. 439 



the genus Felis there is a tendency to the loss of the second 

 superior premolar, it frequently being absent in old individuals, 

 and thus is indicated the probable derivation of the genus 

 Lynx. This genus occasionally loses the superior molar and so 

 in exceptional cases we arrive at a dentition comparable with 

 that of Fusmilus, the extreme reduction, however, taking place 

 in the other jaw. In several species of Felis posterior cutting 

 lobes are added to the premolars and an anterior basal cusp is 

 indicated on the superior sectorial. Comparing the dentition 

 with that of Machcerodus or Srnilodon, it differs in the reten- 

 tion of the internal cusp of the superior sectorial and the 

 presence of an additional superior premolar. 



Phylogexy of the Felidce. 

 Present systems of classification. 



Cope, in his publication on the "Extinct Cats of -North 

 America,"* has based his classification upon the basi-cranial 

 foramina, making two families, the Felidse and ISTimravidse, 

 according to the following definitions. 



Felidse. — JSTo distinct carotid foramen nor alisphenoid canal, 

 condylar foramen entering the foramen lacerum posterius. No 

 post-parietal and generally no post-glenoid foramina. 



ISimravidse. — Carotid and condylar foramina entirely dis- 

 tinct from the foramen lacerum posterius ; an ali-sphenoid 

 canal and post-glenoid and post-parietal foramina. 



This classification includes Machserodont members in each 

 family. Prooelurusis considered as the genus from which the 

 true Felidse may have been derived through jPseudmlurus, if 

 indeed these two genera are not the primitive members of that 

 family. The Machserodont members of the JNimravidae are 

 suggested as the ancestors of the Felidse. It should be re- 

 marked here that Cope's classification, based upon structural 

 characters, does not permit of a phyletic interpretation, since 

 the families as constituted by him are of polyphyletic origin 

 as I interpret his meaning. 



Zittelf establishes three subfamilies, the Proaelurinse, Ma- 

 chserodinse, and Felinse, defining them as follows : 



Proselurinae. — Dental formula f , ^, -f-, -J-, lower carnassial 

 with strong cutting talon skull elongated. Lower jaw slender, 

 small in front with curved lower border ; long-legged, fore and 

 hind feet semi-digitigrade and pentadactyl. 



Machserodinse. — Dental formula 3 -4^ ~ rj^f- \-. Upper canine 

 large and powerful, saber-shaped, compressed with anterior 

 and posterior cutting edges. Front pms more or less reduced. 



*Cope, Amer. Nat, 1880, p. 834. 

 f Handbuch der Paleontologie, 1893. 



