WATER VOLE. 321 



the eyes small, and not very prominent ; the ears sliort, 

 scarcely conspicuous beyond the fur ; the cutting teeth of 

 a deep yellow colour in front, very strong, chisel-shaped, 

 considerably resembling those of the Beaver; the surface 

 of the grinding teeth formed of alternate triangles ar- 

 ranged on each side of the longitudinal axis. In all 

 the Voles the flat crowns of the grinders are divided by 

 the folding of the enamel into a number of triangular 

 cemental spaces or hollows, and the number and form of 

 these have been shown by Blasius and others to afford 

 good specific characters. In the present species the 

 second upper grinder has four spaces and five external 

 and internal angles ; the third has five spaces, of which 

 the two last are sometimes joined, and seven angles ; 

 the first lower grinder has seven spaces and nine angles. 

 Fore feet with four complete toes, the last phalanx only 

 of the thumb being conspicuous beyond the skin; hinder 

 feet with five toes, not webbed, though connected to a 

 short distance from the base ; tail more than half the 

 length of the body, covered with hairs, of which those on 

 the inferior surface are rather long, and probably assist 

 the animal in swimming by forming a sort of rudder of 

 the tail. Fur thick and shining ; of a rich reddish-brow n 

 mixed with grey above, yellowish grey beneath. 



Dimensions: — • 



Incli. Lines. 

 Length of the head and body . . \ .8 4 

 ,, of the head . . . . . .110 



,, of the ears ...... 5 



,, of the tail ...... 4 8 



A black variety of this species has long been known, 

 and has been described by Pallas, and by several other 

 Continental zoologists. It is identical with the animal 

 described by Mr. Macgillivray in the sixth volume^ of the 



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