134 Bulletin American Museum of Natural History. [Vol. XIl, 



and Cynodictis in almost every character. The entirely intermedi- 

 ate character of the skull and teeth is well shown in our drawings: 

 especial attention should be drawn to the postero-internal cusp 

 on p^; short jaws with deep muzzle and round blunt premolars ; 

 broad low sectorials, with additional postero-external cusp on 

 trigon of my ; reduced m^ ; lower incisors in a straight row. 

 Eyes set far forward, skull short, arches wide. On the other 

 hand the resemblance to Cynodictis is closer in the form and cusp- 

 arrangement of the teeth ; palate terminating opposite m-^-, ali- 

 sphenoid canal ; occiput not so much expanded ; retention of 

 m^ ; m-g- not lengthened out. 



In the skeleton the same story appears. The limb bones are 

 like those of Cynodictis with varying amounts of change to Procyon- 

 Only in the hind foot is there any difficulty. Here the first toe 

 is more reduced in Phlaocyon than in Procyon, which makes it 

 seem probable that P. leucosteus is slightly off the line from 

 Procyon lotor. 



The resemblance to Bassariscus is even closer. But Bassariscus 

 cannot be considered as the living representative of Phlaocyon. 

 It shows less departure from Cynodictis in many characters, es- 

 pecially in the shape of the upper molars and lower sectorial and 

 slender jaw ; the postero-internal cusp of the upper sectorial is 

 not developed in one species, and although it is present in the 

 other, the tooth retains much more of its trenchant function. 

 The loss of m-y is an advance on Phlaocyon ; on the other hand, 

 the eyes are not set so far forward, nor is the muzzle so much 

 shortened or the arches so wide. The brain is very much larger 

 in proportion, as might be expected, but the feet are precise 

 copies of those of Cynodictis. 



With Nasua the comparison is not so close as with Procyon. 

 The long skull, large dagger-shaped canines, comparatively nar- 

 row, square occiput, reduced and peculiarly shaped bullae, carry 

 it out of the probable line of evolution pursued by Phlaocyon. 

 The limbs and feet are somewhat nearer to Phlaocyon in some 

 characters ; the feet have the internal toe unreduced. 



Cercoleptes is much more aberrant in the skull and teeth and 

 yElurus has a different pattern of teeth. Altogether Procyon 

 seems to come nearest to fulfilling the conditions required of a 

 descendant of Phlaocyon. 



