1*78 PROCEEDINGS OF THE ACADEMY OP [1879. 



normal variations. These are, however, not so frequent as to 

 invalidate the classification to which they form the exceptions. 



The Canidee appeared in the Upper Eocene period, and the 

 genus Ganis was well represented by species in the lowest Mio- 

 cene in Europe and the United States, The other genera are 

 represented by fewer species, and many of them are extinct. The 

 foxes ( Vulpes) are the most numerous of them, and but few extinct 

 species of them are known. America presents us with the greatest 

 variety of genera, as Enhydrocyon, Temnocyon, and Palseocyon 

 extinct, and Icticyon, extinct aud recent. Speothus, extinct in 

 America, still exists in Asia. 



The most complete catalogue of the species Canidse is that of 

 Dr. Gra} r . In his work the author brings together observations 

 of various naturalists, and adds a number of his own. He admits 

 a large number of generic divisions, but many of these, like those 

 of his Felidse, are simply founded on specific characters. A few 

 good genera, however, exist, and a synopsis of their characters is 

 given below. The genus Megalotis is here excluded from the 

 Canidse on account of the unspecialized character of the superior 

 sectorial tooth, as is done by Dr. Gray : 



I. True molars . 



Premolars f ; inferior sectorial with internal tubercle. 



Amphicyon. 



II. True molars f. 



Premolars | ; inferior sectorial with internal tubercle. 



Thous. 



III. True molars . 

 a. Premolars f . 



/3. Inferior sectorial without internal tubercle. 



Heel of sectorial cutting. Palseocyon. 



/3j3. Inferior sectorial with internal tubercle, 

 y. Four toes in the manus ; 



A sagittal crest. Lycaon. 



77. Five toes in the manus. 

 8. Heel of sectorial simply cutting. 



A median sagittal crest (?toes). Temnocyon. 



58. Heel of sectorial concave, with raised borders. 



Pupil round; temporal fossa with simple superior border. 



Canis. 



