Mus decumanoïdes,[15] _Waterh._ in “Catalogue of the Mammalia
preserved in the Museum of the Zoological Society of London.”
_M. suprà fuscus, griseo-lavatus, subtùs albus: pedum pilis sordidè
albis; caudâ corpore cum capite paulò longiore; auribus mediocribus:
pilis perlongis in dorso crebrè inter cæteros commixtis._
DESCRIPTION.—The general tint of the upper parts of this rat, is
grayish brown, (very nearly resembling that of _Mus decumanus_);
the longest hairs, which on the hinder portion of the back are one
inch and a half in length, are black; the ordinary hairs are black
at the apex, there is then, on each hair, a considerable space
occupied by pale yellow, and the remaining, or basal portion, is
grayish white; the under fur is gray: the hairs of the chin,
throat, and under parts of the body, are white, and without any
gray colour at the roots: the feet are covered with dirty grayish
hairs: the tail, which is slender, is very sparingly furnished
with minute black hairs, both above and beneath: the ears are of
moderate size, of a brownish flesh-colour, and, to the naked eye,
appear to be destitute of hair. The hairs of the moustaches are
most of them black at the base, and grayish at the apex.
In. Lines.
Length from nose to root of tail 7 6
of tail 7 6
of tarsus 1 4¼
of ear 0 7½
from nose to ear 1 7½
Habitat, James Island, Galapagos Archipelago, Pacific Ocean,
(_October_.)
This species is scarcely equal in size to a full grown common black rat,
(_Mus Rattus_), the head is rather shorter in proportion, the tarsi are
smaller, and the tail is longer. In the character of the fur, and length
of the hairs, it _very_ closely resembles that species: the ears are
larger than in _M. decumanus_, and about equal to those of _M. Rattus_.
In having the hairs of the under parts of the body of an uniform colour,
(i. e. not gray at the base,) it resembles the _Mus Tectorum_ of Savi;
but the large size of that animal, the greater length of the fur, and
its colouring, all serve to distinguish it from the present species,
which I may here observe, is truly an old world form, and very distinct
from another species, also from the Galapagos, which is hereafter
described.
“It is very common in James Island, but is not found on all the islands,
if on any other in the Archipelago. Although its appearance is so like
that of the common rat, yet its habits appear to be rather different: it
is less carnivorous, and does not appear to be so strongly attached to
the habitations of man. This island was frequented, about one hundred
and fifty years since, by the vessels belonging to the Bucaniers; so
that the common rat might easily have been transported here. And if a
very peculiar climate, a volcanic soil, and strange food, can together
produce a race, or strongly marked variety, there is every probability
of such change having taken place in this case.”—D.