Mus messorius [Harvest Mouse].
This sleek little thing, the smallest of British quadrupeds, is now well ascertained to be a native of Banffshire. I have myself taken it several times.
Mus rattus [Black Rat].
This, the native British rat, though at one time very abundant, is so no longer. It has been expelled or driven back, as the Celts have been by the Scandinavians, by the Norway rat. The black rat is seldom seen now. Pure white varieties have been found.
Mus decumanus [Norwegian Rat or Rottin].
Very plentiful, and bids fair, erelong, to extirpate his weaker relative, the Black Rat. See [p. 113].
Arvicola amphibia [Water Rat].
To be found on the banks of all our streams. It is sometimes turned up with the plough, at a considerable distance from the water. It is a curious circumstance that the water rats of England are mostly of a light brown colour, whilst those of Scotland are usually jet black.
Arvicola agrestis [Short-tailed Field Mouse].
Plentiful, and very destructive to young trees.