50 THE BRITISH MAMMALS : THEIR GENERA AND SPECIES. 



jaw the third molar has three prisms, the second four, and 

 the first five ; in the lower jaw the third has three prisms, 

 the second three, and the first seven. Its ears are larger than 

 those of the Field Vole, which it resembles in habits. Like that 

 species, it has three or four litters in a year of about five at a time, 

 and like it, will occasionally feed on insects ; but it does not limit 

 itself so exclusively to cultivated ground, and frequently settles in 

 the woodlands, burrowing under the roots exposed in the lanes and 

 bye-paths, or taking up its quarters in any deep hole it may find, 

 provided that it be a foot or so above the level of some of the 

 ground outside. It ranges well up into the north of Scotland, 

 and right across Asia into China. The usual exception, however, 

 holds good, for there are no Voles in Ireland. 



Monodon. Plate xxiv. GET ACE A. 



63. monoceros, NARWHAL. Colour mottled grey above, white below ; 

 head short, beakless, and rounded ; a long spiral tusk, 

 or two such tusks, in the male. 



This is an Arctic species of which as yet only four examples have 

 drifted on to the British coasts. It derives its name of Nar-whal, 

 the corpse whale, from its corpse-like colour. In the female all the 

 teeth are rudimental, but in the male the front one on the left-hand 

 side is developed into a long ivory tusk, twisted in a close spiral 

 from left to right. The corresponding tooth on the right-hand side 



NARWHAL. 

 (Monodon monoceros.} 



is generally small, but occasionally similarly developed with a 

 similar sinistral twist. The dorsal fin is represented by a low ridge ; 

 the flippers are short, broad, and rounded, the second and third 

 digits being nearly equal, and longer than the fourth. There are fifty 

 vertebrae, of which the atlas and axis are free, and there are twelve 

 ribs, of which eight are double-headed. The tusk is about half 

 as long as the body, and the body attains a maximum of about 

 fifteen feet. The Narwhal is gregarious, and feeds on fishes, cuttles, 

 and crustaceans. 



