Sub-family : Murine 



The Typical Rats and Mice 



This sub-family of Rodent animals includes the 

 common Rats and Mice with which v/e are all so 

 familiar ; and a number of other species. The entire 

 group of typical Rats and Mice in the sub-family 

 Murines inhabit the Old World, with the exception 

 of Madagascar, none of them being native to 

 America. The common Brown Rat (Rattus norve- 

 gicus), the Black Rat (Rattus rattus), and the House 

 Mouse (Mus musculus) occur in the New World, 

 but they have been introduced there from the Old 

 World by trading ships. 



Genus : Rattus 



The Rats and Mice of this genus are characterised 

 by the incisor teeth being narrow and smooth ; the 

 crowns of the molars covered with tubercles ; tip 

 of the muzzle naked ; fur soft, and sometimes 

 mixed with coarse hairs ; eyes large, bright and 

 prominent ; colour of the body plain ; ears com- 

 paratively large ; tail long, with overlapping rings 

 of scales, and nearly destitute of hairs ; a flat nail 

 on the first toe of the front foot ; all the other toes 

 with claws ; first and fifth digits not shortened. 



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