MAMMALIA. 13 



Fam. CASTORIDJE. 



Castor fiber L. (gurnpean eaber. 



The only grounds we possess for surmising that the beaver 

 ever inhabited Yorkshire are afforded by place-names. 

 Beverley is supposed to have derived its name from this 

 animal ; while Beaverholes and Beaverdike in the Forest 

 of Knaresborough, and Beevor Hall or Beverhole, near 

 Barnsley, have their derivation also ascribed to this source. 

 The places so named appear to have been suitable to the 

 habits of this animal. 



Section MYOMORPHA. 

 Fam. MYOXID.E. 



61. Muscardinus avellanarius (L.). Dormouse. 



Generally but very thinly distributed over the county ; more 

 abundant in densely wooded districts. No doubt it is 

 much overlooked from its retiring habits. 



Fam. MTIRID.E. 



Sub-fam. MURING. 



62. Mus minutus Pall. Harvest Mouse. 



Very irregularly and thinly distributed, and scarce. 



63. Mus sylvaticus L. Long-tailed Field Mouse. 



Generally distributed and abundant. 



64. Mus musculus Z. Common House Mouse. 



Universally distributed and abundant wherever there are 

 human habitations. 



65. Mus rattus Z. Black Rat. 



Extremely local, appearing to occur only at Stockton-on-Tees, 

 where it is not unfrequent in one or two old buildings. 

 Is reported as having been taken in various other places 

 scattered irregularly over the county, but in the rural dis- 

 tricts it is probable that the black variety of the Water 

 Vole has been mistaken for it ; and those reported for the 

 manufacturing and seaport towns are importations. 



