The skull of this animal, is rather shorter and broader than that of
_Mus Musculus_, the upper surface is more arched, the zygomatic arch is
much more slender, and the nasal bones are rather broader. In the
convexity of the upper surface, and the slenderness of the zygomatic
arch, this skull very nearly resembles that of _M. gracilipes_; this
latter, however, has the zygomatic arch more convex, projecting more
suddenly on the anterior part, and the interparietal bone smaller.
Length of skull 10 lines, width 5½, length of nasal bones 4 lines,
distance between the outer side of the incisors, of the upper jaw, and
the first molar 2⅞ lines. See Plate 34, fig. 3. _a_.
The dentition is figured in Plate 34, figs. 3. _b_ and _c_.
This mouse is rather less than _M. Musculus_, the tail is much shorter
in proportion, the fur is longer and softer, and the ears are more
distinctly clothed with hair.
The pale and delicate yellow colour of the upper parts of the body, and
the pure white of the under parts, renders the present species
conspicuous amongst its congeners. I may further remark that the white
colour which in the Muridæ (when it occurs) is usually confined to the
under part of the body, or extends but slightly on the sides, is in the
present animal extended considerably on the sides of the body, and
occupies an equal portion with the yellow of the upper parts. The name
_bimaculatus_ is applied to this animal on account of the two
conspicuous white patches, which are situated behind the ears.
In affinity as well as in appearance it most nearly approaches to _Mus
gracilipes_ and _M. elegans_; with no other species of the genus _Mus_,
here described, can it be confounded, since these only have the tarsus
hairy beneath.
The principal points of distinction between the present animal and _Mus
elegans_, are noticed in the account of that species.
“This mouse, when alive, had a very elegant appearance. A countryman,
who brought it me, found six of them living together in one burrow.”—D.
MUS GRACILIPES.
PLATE XI.
Mus gracilipes, _Waterh._, Proceedings of the Zoological Society of
London, for February 1837, p. 19.
_M. suprà flavo-lavatus; pilis pone aurem utramque, labiis, corporeque
subtùs, albis; pedibus parvulis, gracilibus, carneis, suprà et ad
calcem pilis albis tectis; caudâ gracili, pilis albis instructâ,
quoad longitudinem corpus ferè æquante; auribus mediocribus; vellere
mediocri et molli, pilis omnibus ad basin plumbeis._
DESCRIPTION.—General colour very pale yellowish brown, a tint produced
by the admixture of black and pale fawn colour; the hairs of the
ordinary fur being of the latter tint near the apex, and dusky at
the apex, whilst the longer hairs are black. The feet, tail, under
parts of the body and the sides of the muzzle, are pure white. All
the hairs of the body, (which are soft, and of moderate length),
are deep gray at the base. The ears are of moderate size, well
clothed with hairs, of which those on the inner side are
yellowish, and those on the outer, are brown on the anterior part,
and white on the posterior. A small tuft of white hairs springs
from the neck immediately behind the ears; this tuft is hidden
when the ears are folded back. The tail is slender and short,
(being not quite equal to the body in length) of a pale
flesh-colour, and sparingly furnished with minute white hairs. The
feet are very small and slender, and the naked parts are of a pale
flesh-colour. The sole of the foot is covered with hairs; the toes
beneath, and the tubercles (which are as in _Mus Musculus_),
however, are naked. The hairs of the moustaches are of moderate
length, and of a blackish colour, some of them, however, are
grayish white.
In. Lines.
Length from nose to root of tail 2 10
of tail 1 7
from nose to eye 0 4⅓
from nose to ear 0 8¼
of tarsus (claws included) 0 6½
of ear 0 4¼