MUS DECUMANUS. 97 



Genus MUS. 



Upper incisors rather short, wedge-shaped ; lower ones 

 long, compressed, curved, and very sharp ; molars simple, 

 "with tubercular summits, their length and breadth nearly 

 equal ; muzzle elongated ; ears oblong or rounded, often 

 naked ; eyes prominent ; front feet with foiu' claws and a 

 thumb, which is very small, and little more than a tuber- 

 cle ; hind-feet "\^'ith five claws ; tail, almost in every case, 

 either as long as, or longer than the body, rounded, com- 

 posed of numerous scaly rings, with short stiff haii'S be- 

 tween them. Most of the species are vegetable feeders, 

 but some feed also on animal substances. 



Mus decumanus. 



Mus decumanus, Desm. Mamm. Sp. 473 ; Bell, Brit. Quad. 

 Norway Rat. Brown Bat. 



Description. — Tail shorter than the body, with rather 

 more than 200 rings ; colour of the upper parts greyish 

 brown, with a ta^vny tint, resulting from each hair being 

 dusky grey at the roots, and yellowish brown at the tip ; 

 a few stiffish blacker hairs are scattered among the others ; 

 under parts dii'ty white. The fur is generally rough, 

 i. e. not lying smoothly close to the body ; ears as broad as 

 long, rounded at the extremities, almost naked, one-third 

 of the length of the head. 



Length of head and body, 11 inches ; head, 2 inches 

 4i lines ; ears, 8|- lines ; tail, 8 inches 4 lines. 



Breeds several times in the course of the year, pro- 

 ducing ten, twelve, or even fourteen young at a birth ; its 

 voracious habits are well known, there being scarcely any 

 animal or vegetable substance which it will not devour. 



Was first observed in Eui'ope, in the South of Russia, 

 about the year 1727, having come from the neighbour- 



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