Genera 0/ Felicias and CanicUe. 93 



unspecializecl character of the superior sectorial tooth, as is 

 done by Dr. Gray. 



I. True molars f. 



Premolars |; inferior sectorial with internal tubercle. Amphicyon. 



II. True molars f. 



Premolars | ; inferior sectorial with internal tubercle. Thous. 



III. True molars f . 

 a. Premolars f. 



/8. Inferior sectorial without internal tubercle. 



Heel of sectorial cutting Talceocyon. 



/3/3. Inferior sectorial with internal tubercle. 

 y. Four toes in the manus. 



A sagittal crest Lycaon. 



yy. Five toes in the manus. 



8. Heel of sectorial simply cutting. 



A median sagittal crest (? toes) Temnocyon. 



88. Heel of sectorial concave, with raised borders. 

 Pupil round ; temporal fossa with simple supe- 

 rior border Canis. 



Pupil erect ; temporal fossa with simple supe- 

 rior border Vulpes. 



Pupil erect ; temporal fossa bounded above by 



a rib-like crest Tlrocyon. 



aa. Premolars | . 



Inferior sectorial with internal tubercle and cutting 



heel Enhydrocyon. 



Inferior sectorial with internal tubercle and wide 



tubercular heel . . . ■ Tomarctus. 



TV. True molars f. 

 a. Premolars |. 



Inferior sectorial with internal tubercle Speothus. 



Inferior sectorial without internal tubercle (superior 



molar sometimes one) Synagodus. 



aa. Premolars f . 



Inferior sectorial without internal tubercle (incisors 



caducous) Dysodus. 



V. True molars h 



Premolars \ ; inferior sectorial with internal tubercle. Icticyon. 



It is discoverable that the series represented by the above 

 genera is a part of the greater line of the digitigrade Carni- 

 vora, embracing the greater part of it, which is less specialized 

 than, or inferior to, the part covered by the Hyaenidre and 

 Felidge. Without entering into the relations of the Canidaa 

 with the civets and Mustelidre, it may be remarked that the 

 genera display a successive reduction in the number of pre- 

 molars and molars from the more ancient to modern geologic 

 times. It is interesting to note that the genera presenting 

 the greatest reduction in all respects [Synagodus and Dysodus) 

 are now only known in a domesticated condition. Another 

 reduction is seen in the number of tubercles of the inferior 

 sectorial. 



