190 NORTH AMERICAN MUSTELID^. 



established upon differences which are here nothing but fortu- 

 itous individual variations, or even the progressive changes 

 with age during the life of the same individual. A Skunk's 

 skull is as variable in shape as its pelage is in color. (Compare 

 Plate X with XI, or Plate XIII with XIV, and see what ex- 

 traordinary differences skulls of the same species may show.) 

 The general pattern of coloration, and the colors themselves, 

 are likewise diagnostic of this subfamily, as all the species are 

 black and white. 



The anal armature. 



Xo general sketch, however cursory, of leading features of 

 this subfamily should fail to note the point which renders the 

 Skunks infamous, makes their very name an opprobrious epi- 

 thet, and almost forbids its use in the ordinary conversation of 

 the polite. The matter is so notorious that comment may be 

 confined to the zoological aspects of the case, including a refu- 

 tation of various absurd notions still current among the vulgar. 

 Special interest attaches to the subject, since it seems probable 

 that there is some occult connection between failure of the sup- 

 ply of the fluid and a state of the system in which the saliva 

 of the animals is capable of inoculating a disease similar to 

 hydrophobia. • 



It was supposed for many years that the intolerably offensive 

 fluid was the animal's urine, voided by an ordinary act of mic- 

 turition, but with malice prepense. Its wide diffusion was 

 sometimes fancied to be secured by means of the bushy tail, 

 which, charged with the licjuid, served as a mop to flirt it 

 around. The obvious difficulties in the way of anatomical in- 

 vestigation long kept the facts in the case concealed. 



The fluid is the secretion of certain glands situated in the 

 perinaium, on each side of the rectum. So far from being pecu- 

 liar to Skunks, similar glands exist throughout the Mustelida^^ 

 and are, in fact, among the characteristic structures of the fam- • 

 ily. In the il/ej^/ii/mfr, however, they reach the maximum of 

 development, and their secretion acquires qualities which make 

 it the most i)enetrating, diffusible, and intolerable of animal 

 effluvia. The anatomical structure is fully described beyond ; 

 here I need only advert to some leading features. 



Each gland is a secretory sac enveloped with a muscular tunic, 

 and furnished with a duct to convey the secretion j the orifice 



