EXTEKNAL CHARACTERS OF THE MUSTELIDiE. 813 



the thickening of the supra, tragus is larger and valvular, and the 

 edge of the cavity has a small soft membranous flap just above 

 the supratragus, which is especially well developed in Plesiogale. 

 ' Moreover, the antero-internal thickening curves sharply beneath 

 the supratragus posteriorly. In Gale, Jliistela, and Plesiogale 

 the bursa is almost or quite as well developed as in Martes, but in 

 Puforius it is reduced to a marginal slit, owing to the reduction 

 in size of the posterior fl-ap, the edoe of which is nearly straight. 

 (Text-figs. 27, A ; 30, A.) 



Gido has the pinna like that of Martes, but relatively smaller 

 and provided with a smaller bursa ; and the pinna of Melogale 

 is very like that of JIusiela and Gale, the bursa, tragus, and 

 antiti-agus being well developed, but the supratragus is less 

 valvular, the antero-internal ridge descends more vertically, and 

 there is a little pouch above the hollow. (Text-fig. 30, G.) 



Tayra and Grison also resemble Mustela and Gale in the pre- 

 sence of the upper membranous flap, the valvular supratragus, 

 the posterior curvature of the antei-o-internal ridge beneath the 

 supratragus ; but differ in the reduction of the bursa to an even 

 greater extent than is seen in Putoi'ius. The posterior flap is 

 continuous above and below with the margin of the pinna, and 

 the anterior flap is represented by a very shallow ridge of in- 

 tegument a little in front of it, so that the pouch is reduced to a 

 minimum. In Grison and Grisonella the valvular supratragus 

 and the flap above it are larger than in Tayra; and in Grisondla 

 the anterior lidge of the bursa is shorter than in Grison. (Text- 

 fig. 28, A, D.) 



In Ictonyx, and also in Pcecilictis and Pwcilogale, judging from 

 dried skins, the pinna differs essentially from that of Mustela, 

 Gale, and Putorius in the total absence of all trace of the bursa 

 and of the membranous flap above the supratiagus. Otherwise 

 it is similar. (Text-figs. 29, A ; 30, B.) 



In Meles and Taxidea the pinna is smaller than in Ictonyx, and 

 the supratragus has a simple subglobular thickening as in Martes. 

 Otherwise they are tolerably similar ; the pinna is less salient in 

 Taxidea than in Meles. 



In Ltitra the pinna, although much reduced, is of the same 

 simple type as in Meles. In Hydrictis it is simplified by the 

 almost complete suppression of the tragus and antitragus and of 

 the supratragus apart from the subglobular thickening. 



In Sjnlogale, Mephitis, and Conepatus a noticeable peculiarity 

 in the pinna is the entire absence of the tragal thickening, so 

 that the external oi-ifice of the ear is exposed and not hidden in 

 a cup-like hollow ; and the cavity of the pinna has no definite 

 anterior i-im. The low antero-internal ridge curves posteriorly 

 beneath the valvular supratragus, which appears to be set higher 

 in the ear than in other genera. The pinna is of comparatively 

 large size in Spilogale ; but in Conepatus — at all events, in 

 G. proteu,s — it is much reduced and scarcely stands away from the 

 head. There is no trace of the bursa. (Text-fig. 30, D-F.) 



