MAMMALIA. 13 
Fam. CASTORIDA. 
Castor fiber Z. European Beaver. 
61. 
62. 
63. 
64. 
65. 
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. MYOXIDZ. 
Muscardinus avellanarius (Z.). 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. MURIDZ. 
Sub-fam. WURINZ. 
Mus minutus Pai. Harvest Mouse. 
Very irregularly and thinly distributed, and scarce. 
Mus sylvaticus Z. Long-tailed Field Mouse. 
Generally distributed and abundant. 
Mus musculus Z. Common House Mouse. 
Universally distributed and abundant wherever there are 
human habitations. 
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. 
