14 NORTH AMERICAN MUSTELIDiE. 



to ]\rartens and Weasels, is sufficient to invalidate such a 

 hypothesis. It is true that it is emitted when the animals are 

 angered, terrified, or put in pain ; but these are merely circum- 

 stances of irritation akin in many respects to other forms of 

 excitement. It is more probable that the secretion subserves 

 a purpose in the sexual relation, as it is undeniably a means 

 whereby the sexes may discover and be attracted toward each 

 other. 



2. — lii'snmc of the several types of structure of the odoriferous 

 glands in Mustelidce. 



The Ferrets and Martens exhibit one general plan of struct- 

 ure of the anal glands. At each side of the termination of 

 the rectum, there is an oval body consisting of a tunic of mus- 

 cular striped fibres enveloping a mass of glands, in the midst 

 of which is a receptacle of variable capacity, containing a liq- 

 uid differing little in its properties, which is poured out through 

 a short duct opening upon a pore at each side of the anus. 



In the Badgers, Skunks, and Eatels, there are decided mod- 

 ifications of this plan. In the last two named, the true anal 

 glands alone exist, and these are quite different from those of 

 the j\[nstelhuv. Instead of a thin and simple muscular envel- 

 ope of the gland, w^e find a thick fleshy tunic, formed of two 

 layers of interlaced fibres, capable of sudden strong compres- 

 sion of the receptacle. This latter is not a small simple sac 

 with laminar walls, such as is found in the centre of the gland 

 of MustelUuv, but is an enormous reservoir, with a dense resist- 

 ing fibrous coat, always containing a considerable quantity of 

 the follicular product. The glandular substance is not spread 

 all over this central capsule, but is restricted to a particular 

 portion, and contrasts by its dark color with the white surface 

 of the envelope of the pouch. The contents of the receptacle 

 are sufficiently offensive to justify the profound and universal 

 disgust which these animals excite in consequence of their 

 curious and very efficacious means of defence. The voiding of 

 the liquid must be sudden; and it does not suffice that the re- 

 ceptacle is large and powerfully muscular ; the offensive liquid 

 must be directed far backward, so as to flow as little as possible 

 upon the rectal mucous membrane; consequently the opening 

 is large and upon the summit of an umbilicated papilla, around 

 which rests a cutaneous fold, which in a measure directs the 

 discharge. 



