SQUIRRELS, BEAVERS, DORMICE, AND RATS 253 



the nose to the root of the tail, while the somewhat long tail 

 measures another 4J in. The fore feet, as usual, have only four 

 complete toes, the thumb being merely marked by a claw. The 

 hind feet have five complete and somewhat long toes with just 

 the commencement of a webbing. The tail is thickly haired, 

 especially on the under side. The body is densely covered with 

 long, fine, silky hair, exquisitely soft, and very impermeable to 

 water. When the creature is under water the tips of the fine 

 hairs are hung with innumerable minute air bubbles, which give 

 it quite a gray appearance. The ears are very short, set close to 

 the head, and almost concealed in long, silky hair. The eyes 

 are small and deep-set. The incisor teeth are very distinct from 

 that of the other voles, in that they are deep orange or chestnut 

 colour in front. In their shape they somewhat recall those of 

 the beaver. The molar teeth are long, and have the same 

 remarkable alternate triangles marked by zigzag folds of enamel. 

 These prismatic spaces (as they are called), beginning with the 

 first molar on each side of the upper jaw, are respectively five in 

 the first tooth, four in the second, and four or five in the third. 

 In the lower jaw the first molar has seven, the second five, and 

 and third three spaces.^ The fine glossy hair is a rich yellow or 

 reddish-brown, mixed with a good deal of gray, and even a 

 bluish tinge owing to the gloss. The yellow or red is intensified 

 on the cheeks, on the fore limbs, and on the belly ; but varieties 

 of the water vole are often almost black, or a dark gray. The 

 black variety is generally met with in Scotland and in the east of 

 England. The soles of the feet are flesh-colour, and the claws 

 purple or reddish. The number of teats in the female is five 

 pairs. This vole is not so prolific in the number of litters as in 

 the smaller species. In all probability many individuals only 

 have one brood in the course of the year — in the late spring or 

 early summer. Others may produce a second brood in October. 

 There are from five to six young in a litter, and these are born 



■^ As against (in the upper jaw) five, five, and six prismatic spaces in the 

 upper molar teeth, and nine, five, and three in the lower molar teeth in the 

 field vole, showing that smaller Microtus in this respect to be more speciaUsed. 



