the smaller British Mammalia. 269 



Between the A. amphibius and the A. ater of MacGillivray. 

 The following is a correct description of the colours : 



Extreme tip of the snout dusky ; cheeks and upper part 

 of the head very deep brown, with a slight reddish tinge, the 

 tips of the hairs being of this colour ; back, from between the 

 ears to the root of the tail, wholly black, the short pile as 

 well as the long hairs being of one uniform tint throughout ; 

 sides very deep brown, slightly tinged with reddish ; belly 

 deep ash-grey, with a tinge of reddish like the sides ; chin 

 ash-grey, without the reddish tinge, which is deepest just 

 beyond the contour of the chin, and between the fore-legs ; 

 all the feet covered with very short black hairs above, smooth 

 and naked and paler underneath ; tail black, and of one colour 

 throughout. 



The length of this individual was 5 inches 3 lines, exclusive 

 of the tail, which was 3 inches 3 lines. I have observed, like 

 Mr. MacGillivray^, that the black variety of this species is 

 generally much smaller than the brown. Yet I have known 

 a few instances to the contrary ; and one individual, which 

 was the most uniformly deep-coloured one I ever saw, was 

 also the largest. I regret, however, that the note which I 

 made of its exact dimensions has been lost. 



(11.) Arvicola arvalis. — This species, like the last, appears 

 subject to some variation of character, particularly as regards 

 colour ; so much so, as at one time to have led myself, as well 

 as others, to suspect there might be two species confounded 

 under one name. 



Two individuals which I have had by me in spirits several 

 years, have the feet and tail yellowish, as described by De 

 Selys-Longchampsfj the latter being entirely of one colour; 

 the fur above reddish brown, with the ears appearing out of 

 it ; the hair on the under parts of the body rather short and 

 thin, and greyish white, the basal portion of each hair being 

 ash-colour. The larger of these individuals was a female 

 taken in the breeding season, measuring 4 inches 1 line in 

 length, exclusive of the tail, which was 1 inch S^ lines. The 

 upper parts in this specimen were quite as red as in the A, 

 rubidus of De Selys. 



I have since, at different times, obtained many other in- 

 dividuals, in which the snout, feet and tail were deep ash- 

 grey, approaching to dusky instead of yellowish; the tail 

 also exhibiting an appearance of two colours, as in the A, 

 rubidus and A. subterraneus of the above author. Some of 

 these had the fur as described above ; but in others it was 



* Naturalist's Library, vol. vii. (Brit. Quad.) p. 264. 

 t Micromammalogie, p. 1 00. 



