28 ANIMAL LIFE OF THE BRITISH ISLES. 



hairs which make them more efficient as paddles ; and the 

 tapering flattened tail of the adult has a double fringe of strong 

 silver-grey hairs along its underside, constituting a " keel " and 

 making it more efficient as a rudder. The hind foot usually 

 exceeds three-quarters of an inch. The fur is finer and thicker 

 than in the other British Shrews ; and the upper and lower 

 colour areas are sharply separated one from the other. Its 

 aquatic habits have in some districts caused it to be known as 

 Otter-Shrew. The tail is brown above and lighter below. 

 Variation to full black is frequent, and albinos have been 

 recorded. 



The teeth have coloured tips like those of the other Shrews, 



Skeleton of Water Shrew. 



but the points of the incisors are more hooked than in the two 

 species of Sorex\ moreover, there are two teeth less, the 

 dental formula standing thus : z f, c\, p f-, m i| = 30. It is these 

 differences in the teeth that has led to the Water Shrew being 

 placed in a separate genus. 



In wandering quietly along the streamside we may perchance 

 see the Water Shrew sunning itself on a mossy stone by the 

 margin of the water, for it is active by day as well as by night. 

 We may see it make a sudden plunge into the stream, and present 

 a beautiful appearance under water, for the fur carries a good 

 deal of air entangled in it which gives the submerged body a 

 silvery appearance. It chases the whirligig beetles and water- 

 gnats on the surface, or routs at the bottom for caddis-worms 

 and other larvae. Its haunts may often be detected by the 

 little heaps of caddis cases on the bank, which it has brought 



