64 THE MAMMALS, REPTILES, AND FISHES OF ESSEX. 



cautious, and most difficult to trap. His country cousin 

 quickly takes warning after a few have been caught, and most 

 adroitly avoids all snares and gins in the future. 



Dr. Bree has recorded (Field, Oct. 5th, 1872, p. 328) the 

 capture of two hairless Rats at Thorpe-le-Soken. They were 

 entirely without hair, except for their whiskers. He for- 

 warded the specimens to the Museum of the Royal College 

 of Surgeons. 



Family ARVICOLID/E. 



Genus ARVICOLA, Lacep. 



Arvicola amphibius, Desmar. WATER RAT OR WATER VOLE. 



This little animal is common in all parts of Essex, 

 wherever there are sluggish streams, or where stagnant water 

 exists in sufficient quantity to hide it. 



Bell, quoting G. R. Waterhouse, says : " The animals 

 comprising this family (Arvicolidae) have all the essential 

 characteristics of the Muridae, but differ in having rootless 

 molars and in the form of the lower jaw." There are other 

 characters given, but the rootless molars seem to be the great 

 and easily-distinguishing feature separating Muridae and 

 Arvicolidae. 



It will be well to bear in mind that the common Water 

 Rat is sometimes quite black in colour, and has been 

 described by Macgillivray (Hist, of Brit. Quad., being 

 vol. xiii. of the Naturalists' Lib.) under the name of Arvicola 

 ater. This is, however, merely a variety. This form 

 has been occasionally mistaken for the old English Black 

 Rat (Mus rattus], and many of the supposed appearances 

 of the latter animal can thus be explained. 



Its size and numbers considered, the Water Rat does less 

 damage than any other British member of the family. Its 



