“Very common in long dry grass in the valleys of Port Desire.”—D.
The skull is figured in Plate 33, fig. 5, _c_. Fig. 5, _a._ represents
the molars of the upper jaw; fig. 5, _b._ those of the under jaw, and
fig. 5, _d._ represents the posterior molar of the under jaw when more
worn.
It was with some hesitation that I described this as a distinct species
in the Society’s Proceedings. I have now re-examined the specimens, and
still am unable to satisfy myself whether they are varieties of _Mus
xanthorhinus_ or not. Both of _Mus canescens_ and of _Mus xanthorhinus_,
I have before me what I imagine to be an adult and a young specimen. The
adult and the young of _M. xanthorhinus_ agree in being of a _yellowish
brown_ colour, and in having the muzzle and tarsi deep yellow; both
specimens of _Mus canescens_ are of a _gray_ colour, with an indistinct
yellow wash, the muzzle and tarsi being tinted with yellow, as in _M.
xanthorhinus_. Besides this difference in tint, which, perhaps, is
unimportant, _M. canescens_ differs from _M. xanthorhinus_ in having the
head larger, the tail rather longer, and the fur less soft. The
specimens of this animal are both from Patagonia; one of the specimens
of _Mus xanthorhinus_ was brought by Mr. Darwin from Terra del Fuego;
and as the other formed part of Captain King’s collection, it in all
probability came from the same locality. As I only possess one skull, I
cannot speak with certainty as regards the size of the head; the
difference, however, in the stuffed specimens is considerable, and it is
strange that each of the pairs should agree so perfectly, supposing the
difference to be the work of the stuffer’s hands.
18. MUS LONGIPILIS.
PLATE XVI.
Mus longipilis, _Waterh._, Proceedings of the Zoological Society of
London for February 1837, p. 16.
_M. suprà obscurè griseus, flavo lavatus; subtùs griseus; pedibus
fuscis, unguibus longiusculis; auribus mediocribus; caudâ corpore
breviore, suprà nigrescente, subtùs fuscescente; rhinario
sub-producto: vellere longissimo, molli._
DESCRIPTION.—Fur very soft and silky, and extremely long—the ordinary
fur of the back measuring nearly three quarters of an inch, and
the longer hairs one inch in length; ears moderate; tail nearly as
long as the body; muzzle much pointed; general colour gray, washed
with yellow, the under parts pale gray, or grayish white; feet
brown; ears and tail well clothed; the hairs on the inner side of
the ears are chiefly of a yellow colour, those on the upper
surface of the tail are brown-black, those on the under part are
dirty white; the hairs of the back are deep gray at the base,
broadly annulated with yellow near the apex, and dusky at the
apex; the longer hairs are grayish black; the hairs of the
moustaches are dusky at the base, and whitish beyond that part;
the claws are long, and but slightly curved; the incisors are
slender; those on the upper jaw are yellow, and those of the under
yellow-white.
In. Lines.
Length from nose to root of tail 5 4
of tail 3 4
from nose to ear 1 2
of tarsus (claws included) 1 0½
of ear 0 6½