MURID^ 377 



are annulated, the basal and major portions being usually dusky. 

 The first or juvenal coat of the young is distinct from that of 

 adults, and precedes a post-juvenal coat of intermediate 

 character. Two moults, one at each change of season, are 

 probably normal, but their regularity is much interrupted by 

 variable weather, the condition of the animals, and the influence 

 of the long breeding season. The system of pigmentation and 

 the principles of coat pattern are probably somewhat similar 

 throughout the family, but having been chiefly studied in the 

 House Mouse, are described under that species. 



Droppings :— These are very distinct from the more or less 

 rounded crotties of the Leporidce, being elongated, thicker 

 in the middle and tapering to blunt points at each end. 

 Except in size, they are not distinctive as between the various 

 species. 



The British species fall into three sub-families : — the locally 

 extinct Cricetince, or hamster-like rodents ; the Microtince, or 

 voles and lemmings ; and the Murines, or true mice and rats. 



A KEY TO BRITISH MURID^, 



WITH MUSCARDINUS. 



I. EXTERNAL CHARACTERS:— 



I. Size larger ("rats," with head and body not less than 175, hind foot not less 

 than 30 mm.) : — 



I. Tail slightly more than half as long as head\ , „ irrrn r /i 

 and body; ear 16 to 18 mm. . jAlil^JLUI.A. 



(A) Upper side brownish . . .A. amphibius atnphiUus. 



(B) Upper side bUctish . . • {[f „3X*"e% m^^S; 



3. Tail longer than head and body; ear 24 to 25 mm. : — 



(A) Upper side brownish . . . E. rattus alexandrinus. 



(B) Upper side blackish . . . E. rattus rattus. 

 VOL. II. 2 B 



