MUSTELA 385 



against anterior border of pm 3 ; other small premolars not 

 capable of trenchant action. 



Ben/iarks. — The sub-genus Mustela is the most widely 

 distributed group in the genus. It is also the richest in species 

 and local races. About seventy of these are now recognized, 

 eleven of which occur in Europe. 



MUSTELA ERMINEA LinniBUS. 

 (Synonymy under subspecies.) 



Geographical distribution. — Europe from the Arctic coasst 

 to the Pyrenees and Alps, and from Great Britain eastward 

 into Asia. 



Diagnosis. — Skull with narrow brain-case and slightly pro- 

 jecting, scarcely angular mastoid region, the mastoid breadth 

 less than distance from basion to palation ; rostral width across 

 canines usually less than interorbital width ; auditory bullse much 

 longer than broad, nearly parallel sided, rounded posteriorly, 

 truncate anteriorly ; form very slender, the tail slender and not 

 bushy ; colour brown above, whitish below, the line of demarca- 

 tion straight ; a white winter pelage assumed in colder parts of 

 range ; tail always with black tip including more than terminal 

 pencil ; upper lip always at least partly white ; ear usually with 

 a whitish rim. 



External characters. — General form long and slender, the 

 legs short, the body cylindrical, the neck long and nearly as 

 thick as body, tail considerably longer than outstretched hind 

 leg. Ear short but appearing distinctly above fur of head, its 

 outline evenly rounded, both outer and inner surface densely 

 clothed with short hair ; muzzle rather broad and short, the 

 nostril pad sharply denned, entirely naked, separated from upper 

 lip by a narrow hairy area. Palm and sole completely furred in 

 winter, the tubercles bare in summer ; on both palm and sole 

 there is a trilobed, heart-shaped tubercular mass at base of 

 median digits and a small round pad at base of inner digit ; on 

 palm there is an additional posterior rounded pad near wrist. 

 Fur dense and soft, the longest hairs on back about 10 mm. 

 in winter, less in summer ; tail rather closely haired, the pencil 

 full, usually wider than basal portion of tail, its longest hairs 

 about half as long as vertebrae ; fur turning white in winter 

 except in warmer parts of range. Mammae : i 4 — 4 = 8. 



Colour. — Upper parts and outer surface of legs yellowish 

 brown, usually a little darker along middle of back and on head, 

 the underfur and bases of the longer hairs much paler ; under- 

 parts, inner surface of legs and upper surface of feet whitish or 

 yellowish in strong contrast, the line of demarcation between 



2 c 



