416 MR. R. I, POCOCK ON THE EXTERNAL 



There is veiy little to say about the external genitalia of the 

 female. In Procyon and Ailurus the vulva occupies the same 

 relative position as in Caniclse and Ursidte. In both genera it is 

 an oval or egg-shaped excrescence, with. hairy labia surrounding a 

 central pit, the clitoris being a small excrescence near the lower 

 edge of the pit, and above the clitoris is the orifice of the vagina. 

 In AilurvjS the clitoris contains a small bone ; but I have no note 

 of this in Procyon. In Potos the vulva is relatively a somewhat 

 shorter angular prominence, with the orifice forming a transverse, 

 not a vertical, rima — an adaptation possibly to the width of the 

 tip of the baculum of the male. I found no clitoris within the 

 orifice. Beddard did not describe the vu.lva in the female example 

 of Bassaricyon he examined. 



The External Characters as a Guide to Classification. 



A. review of the above -recorded characters brings to light 

 some interesting facts bearing on the classification of the genera 

 examined. 



There is nothing special to say about the vibrissas except their 

 high development in Nasua. 



The external ear shows in its variation generic features, but 

 practically no evidence of close intergeneric kinship. 



The muzzle and rhinai'ium also exhibit good generic chaiacters ; 

 while the rhinarium of Nasua differs max-kedly in its specialization 

 from that of the rest. 



In the case of the feet, however, a marked difl[erence may be 

 noticed between Ailurus and the rest. In the latter a gradation 

 may be traced from Bassariscus through Jentinhia to Bassaricyon, 

 from the latter to Nasua on the one side and to Potos on the 

 other, and from Potos to Procyon. 



Ailurus also stands alone in possessing a specialized glandular 

 area i-ound the anus. The presence of normal anal glands both 

 in Ailurus and Procyon merely indicates the mutual inheiitance 

 of a primitive feature ; but the modifica.tion of these glands met 

 with in Nasua is a.n acquired diflferentiating peculiarity, as also 

 is their loss by Potos. The latter is also peculiar in the possession 

 of the ventral glands. 



Finally, Ailurus differs markedly from the rest of the genera 

 in the scrotal position of the prepuce, the shortness of the penis 

 and baculum, and the structure of the base of the baculum itself. 

 The others retain the primitive abdominal position of the prepuce 

 and the large baculum seen in typical Arctoids, all Cynoids, some 

 ^luroids (e. g. Cryptoprocta), and the Pinnipedes. 



The above-mentioned peculiarities of Ailurus, coupled with the 

 better-known peculiarities of the skull and teeth, justify the 

 severance of that genus from the American Procyonidse as pro- 

 posed by Gray and upheld by Gill, Turner, and Flower, though 



