CLASS MAMMALIA. 61
Mus musculus, Linn. Common Mouse.
Who does not know this foul-smelling, but nevertheless
pretty, little beast? It abounds everywhere, and has followed
man to all parts of the world. Houses, buildings, and corn-
ricks are its favourite haunts, and it does not occur in this
country except in their vicinity. Its original home certainly
was not in Britain.
Albinos occasionally occur wild. In February, 1897,
nearly a score of white specimens, having pink eyes, were
caught in threshing a stack of wheat on Stebbing Ford Farm,
Felstead (Essex County Chronicle, February 26th, 1897).
Mus rattus, Linn. Black Rat.
This, our oldest Rat, was abundant before the advent of
the Brown Rat, called by Waterton and others the " Han-
overian Rat." It is now almost extinct, although still occurring
about the docks and other places in the East-end of London.
The specimens thus met with may not be natives. Probably
the race is kept up by escapes from the vessels lying in the
river in the neighbourhood.
Mr. H. Barclay records (Zool., 1848, p. 616) the trapping
of an immature specimen in a dry bank at Leyton. Two
others were also taken near the same place.
The Black Rat is easily known from the Hanoverian Rat
by the size of its ears, the slenderness and length of its
tail, and by the mouth appearing to be so far under
the nose.
In habits and feeding, there is much in common between
the two species. Mus rattus, however, confines itself to the
upper parts and roofs of buildings : Mus decumanus, to the
basements and drains.