436 BRITISH ARCTOIDEA CHAP. 
many species known popularly as Weasels, Krmines, Stoats, Ferrets, 
Polecats, Minks, and Vison. Not only is the genus common to 
both Old and New Worlds, but in a few cases the species (e.g. 
P. erminea) range from Asia to America. The molar formula is 
Fic. 221.—Polecat. Mustela putorius. x4. 
Pm Md. The form of the body is an exaggerated one, the 
leneth of the trunk to the limbs being very great. The feet 
are more or less hairy beneath, and the animals are digitigrade. 
The nose is grooved. The dorsal vertebrae vary from thirteen 
to sixteen. 
There are four British representatives of this genus :— 
The Polecat, P. foetidus, is a dark brown-coloured animal. — Its 
total length is about 2 feet, of which the tail occupies some 7 
inches. It is a species banned by the gamekeeper, and hence is 
approaching extinction in this country. It is excessively blood- 
thirsty, as are apparently all the members of this genus, and kills 
out of mere wantonness. The Ferret is simply a domesticated 
variety of the Polecat. 
The Stoat or Ermine, P. erminea, is reddish brown above, 
white beneath. In winter, in certain localities, it becomes white 
with the exception of the black tip of the tail. This colour- 
change bears some relation to the degree of latitude. It 1s 
universal in the north of Scotland, rare in the south of England. 
As is the case with some other animals that generally change 
