unable to satisfy myself whether they are varieties of 3Ius xantliorhinus or
not. Both of 3Ius canesceus and of Mus xanthorhinus, I have before me what 1
imagine to be an adult and a young specimen. The adult and the young of
31. xantliorhinus agree in being of a yellowish-brotvn colour, and in having the
muzzle and tarsi deep yellow ; both specimens of 3Ius cauescens are of a gray
colour, with an indistinct yellow wash, the muzzle and tarsi being tinted with
yellow, as in M. xantliorhinus. Besides this difference in tint, which, perhaps,
is unimportant, 31. cauescens differs from 31. xantliorhinus in having the liead
larger, the tail rather longer, and the fur less soft. The specimens of this animal
are both from Patagonia ; one of the specimens of 3Ius xantliorhinus 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 he
the work of the stuffer’s hands.
1 8 . M u s LO N G IPILIS.
Mus longipilis, Waterh., of the Zoological Society of London for February 1837, p. 16.
31. suprà obscurè griseus, flavo lavatus ; subtiis griseus ; pedibus fuscis, unguibus
longiuscuUs ; auribus mediocribus ; cauda corpore breviore, suprà nigrescente, subtiis
fuscescente ; rhinario sub-producto : vellere longissimo, molli.
D e s c r i p t i o n .—Fur very soft and silky, and extremely long— the ordinary fur of
the back measuring neariy 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 claw’s are long, and but slightly curved ; the