S92 THE MIOCENE FATJNA. 



the cats. The dogs of to-day are long-jawed, and they snap in a manner 

 quite distinct from anything seen among the cats. The only dogs that 

 hold on are the short -jawed bulldogs. 



So in the use of the canines, we have the ground of the shortening of 

 the jaw behind and before, and the consequent change of structure, which 

 resulted in the modern perfected Felidce. 



The families are then defined as follows: 



Htpomycteri. 



I. No sectorial teeth in either jaw. 



Toes 5-5 Cercoleptid(B. 



II. Sectorial teeth in both jaws. 

 a. Toes 5-5. 



;9. No alisphenoid canal. 



True molars f Procyonidw. 



True molars i Mustelidw. 



/S/9. Au alisphenoid canal. 



JVIolars quadrate, | Aeluridw. 



Molars longitudinal, f Ursidw. 



aa. Toes 5-4 or 4-4. 

 •Sectorials well developed, an alisphenoid canal Canidw. 



Epimycteei. 



I. Molars l)aplodont. 



Toes 5-4; no alisphenoid canal Protelidce. 



II. Molars bunodont, no sectorials. 



Toes 5-5; an alisphenoid canal Arctictidm. 



III. Molars bunodont, with sectorials, 

 a. Otic bulla with septum. 



[i. Alisphenoid canal and postglenoid foramen, present. 



y. True molars well developed. 



Toes 5-5 Viverridce. 



Toes 5-4 Cynictidce. 



Toes 4-4 , - Surkatidce. 



yy. True molars much reduced. 



Toes 5-5 CryjJtoproctidw. 



Toes 5-4 NimravidcB. 



/5,?. No alisphenoid canal; postglenoid foramen rudimeutal or wanting. 

 Toes 5-4 Felidce. 



aa. Otic bulla without septum. 



No alisphenoid caual, nor postglenoid foramen. 

 Toes 4-4 HycenidcB, 



