BROWN OR NORWAY RAT. 
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the back, from the roots, bluish-gray, then reddish-brown, broadly tipped 
with dark brown and black. On the under surface, the softer and shorter 
hair is from the roots ashy-gray broadly tipped with white. 
VARIETIES. 
1st. We have on several occasions, through the kindness of friends, re- 
ceived specimens of white rats which were supposed to be new species. 
They proved to be albinos of the present species. Their colour was white 
throughout, presenting the usual characteristics of the albino, with red 
eyes. One of this variety was preserved for many months in a cage with 
the brown rat, producing young, that in this instance all proved to be 
brown. 
2d. We have at different times been able to procure specimens of a sin- 
gular variety of this species that seems to have originated in this country. 
For the first specimen we were indebted to our friend Dr. Samuel Wilson 
of Charleston. Two others were sent to us from the interior of South 
Carolina. One was presented to us by a cat, and another was caught in a 
trap. In form, in size, and in dentition, they are precisely like the brown 
rat. The colour, however, is on both surfaces quite black. In some spe- 
cimens there is under the chest and on the abdomen, a longitudinal white 
stripe similar to those of the mink. The specimens, after being preserved 
for a year or two, lose their intense black colour, which gradually assmnes 
a more brownish hue. We examined a nest of the common brown rat 
containing 8 young, 5 of which were of the usual colour, and 3 black. 
The specimen obtained by Mr. Bell of New-York and published by Dr. 
Dekay, New-York Fauna, p. 81, under the name of Mus Aviericanus, 
undoubtedly belonged to this Amriety, which appears to have of late years 
become more common in the Southern than in the Northern States. This 
is eAudently not a hybrid produced between Mus Decumanus and Mus 
Rattus, as those we have seen present the shape and size of the former, 
only differing in colour. 
DIMENSIONS. 
Inches. 
From point of nose to root of tail, - - - - 10 
Tail, - -- -- -- -- - 9 
From point of nose to ear, ..... 2^ 
Height of ear, | 
