CHARACTERS OF THE PROCYONIJXE. 413 



is straight or slightly curved and normally * subcylindrical and 

 attenuated, with the apex expanded transversely and somewhat 

 abruptly to a considerable extent. The sides of the expanded 

 portion are rounded, and the distal margin is tolerably evenly 

 truncated or mesially concave, so that the tip is slightly bilobate. 

 The lower surface of the expanded termination is lightly convex ; 

 the upper to a corresponding degree concave. 



In an adult male of each of the two species examined, namely 

 Nasaa nasua and JV. narica, there is a difference in the length 

 of the baculum. In the former species it measures 63 mm., in 

 the latter 77 mm. Possibly this is a specific character f. 



The baculum of Nasuella is, I believe, unknown. 



The baculum of Bassariscus was figured by Blainville (Ost. des 

 Mamm., Atlas i., Mustela, pi. x.), and described and figured by 

 Gervais (Voy. de la ' Bonite,' i. p. 20, Atlas, pi. iv.). Disregard- 

 ing the club-shaped base, it is tolerably evenly attenuated up 

 to the apex, which has a simple undivided slightly depressed 

 thickening, like the button on a foil. In the specimen figured by 

 Blainville it was rather strongly upcurled in its basal third, with 

 a slight downward distal curve, and measured about 50 mm. In 

 Gervais' specimen it was straighter and measured the same, 

 which, judging from the figure of the skeleton, was about two- 

 thirds the basal length of the skull. In the young example of 

 Bassariscus examined by me — an example in the stage of the tooth 

 change, the milk premolars being still in place — the baculum, 

 resembling in all essential particulars that figured by Gervais, is 

 less than half the basal length of the skull, the latter being 

 65 mm. and the baculum 30 mm. 



The baculum of Jentinkia sumichrasti as figured and described 

 by Lonnberg (Anat. Anz. xxxviii. p. 232, fig. 2, 1911) measures 

 43 mm., is straight and subcylindrical, i. e. only gradually nar- 

 rowed from the distal to the proximal end. The tip is a simple 

 rounded condyle-like thickening ; but close behind it, rather on 

 the underside of the baculum, there is a pair of smaller rounded 

 condyle-like tubercles, recalling the similar accessory processes in 

 the baculum of Potos, which, however, project upwards and out- 

 wards. 



As I have elsewhere remarked, the baculum of Jentinkia is 

 very like that of the Musteline Grison, except that the post- 

 apical processes in the latter are dorsal in direction. The pre- 

 sence of the two tubercles in question distinguishes the baculum 

 of Jentinkia from that of Bassariscus. 



The only account of the baculum of Bassaricyon known to me 

 is that of Hollister, who described it as " 32 mm. in length, 



* In one example of Nasua nasua the bone shows an abnormal flattening on the 

 right side. 



+ In an adult but castrated male of Nasua nasua the baculum measures only 

 52 mm., and is exceedingly slender without any thickening at the proximal end. 

 The penis was correspondingly short as compared with that organ in the entire male. 

 One would perhaps expect the operation in question, if performed early in life, to 

 affect the development of the baculum. 



28* 



