50 
ZOOLOGY OF THE VOYAGE OF THE BEAGLE. 
a deep gray at the base, black at the apex, and narrowly annulated with 
deep yellow near the apex ; on the throat and belly they are of a paler gray 
at the base, and grayish white at the apex. The ears are well clothed with 
brown hairs both within and without, and are for the most part hidden by 
the long fur of the head. The hairs covering the upper side of the feet are 
of a palish ashy-brown colour, and the fleshy portion appears to have been 
brown. The tail is well clothed with hairs, so that the scales are scarcely 
visible ; on the upper side of the tail the hairs are brownish-black, and on 
the under side, they are dirty white. The incisors are very slender ; those 
of the upper jaw are of a very pale yellow colour, and those of the lower 
are white, or nearly so. The muzzle is slender, and pointed. 
Length from nose to root of tail 
of tail 
from nose to base of ears 
In. Lines. 
4 9 Length of tarsus (claws included) 
2 8 of ear .... 
1 2 
In. Lines. 
0 11 
0 3 
Habitat, Chonos Archipelago, {December.) 
This mouse is considerably larger than Mus Musculus , and the great length 
and density of its fur, causes it to appear much stouter in its proportions ; its 
colouring is darker, the tips of the hairs being much more narrowly annulated 
with yellow than in that species. The very small size of the ears will serve to 
distinguish the present animal from its congeners — Mus iongipilis, M. Renggeri, 
M. arenicola, &c. 
The molar teeth of the upper jaw are figured in Plate 34. fig. 8, a ; and 
fig. 8, b, represents the middle and last molars of the lower jaw. 
“ Inhabited a very small island, covered with thick forest, in the central part 
of the Chonos Archipelago.” — D. 
A mouse obtained on the islets adjoining the east coast of Chiloe (where 
Mr. Darwin says it was common) differs from the above in being a little smaller, 
the tail is rather longer, and the ears are a trifle larger. In the feet, claws, 
colouring and character of the fur it agrees, and likewise in the pale colour and 
slenderness of the incisors. Its dimensions are as follows : — 
Length from nose to root of tail 
of tail 
of tarsus (claws included) 
In. Lines. 
4 0 Length from nose to ear 
3 0 of ear 
0 10 
In. Lines. 
0 10 $ 
0 4 
I have not the means of satisfying myself whether this be a distinct species 
or not ; but I think it is not. 
