48 
ZOOLOGY OF THE VOYAGE OF THE BEAGLE. 
Length from nose to root of tail 
of tail 
from nose to ear 
In. Lines. 
4 3 
4 2 
1 0 ± 
Length of tarsus 
of ear 
In. Lines. 
1 1 
0 5 
Habitat, Port Famine, Strait of Magellan. 
This mouse is larger than Mus Musculus ; the tail is rather longer in propor- 
tion ; the tarsi much longer; the ears are not quite so large in proportion to the 
head, (which greatly exceeds that of Mus Musculus in size,) and they are densely 
clothed with hair. The fur is longer. In colour, the animal here described is 
rather darker than the common mouse. I have one specimen however before me 
which very nearly agrees in this respect. 
The dentition is figured in Plate 34, figs. 6, a. and 6 , b. 
From the attention which Mr. Darwin bestowed upon the Muridse of the 
southern parts of South America, I presume his collection affords materials for a 
tolerably complete monograph of the species of that portion of the globe. The 
species above described, however, does not occur in Mr. Darwin’s collection, but 
is here introduced in order to make the work more complete, and that I might 
more clearly point out the distinctions which exist between it and other 
species here described, the account given by Mr. Bennett in the Proceedings 
being very short. 
MUS ARENICOLA. 
Plate XIII. 
Mus arenicola, Waterh ., Proceedings of the Zoological Society of London, for February 1837, p. 18. 
M. supra fuscus, subtus cinerescenti-albus, pallide Jlavo tinctus ; auribus mediocribus 
rotundatis, pilis jlavis fuscisque obsitis ; cauda quoad longitudinem corpus cequante; 
pedibus cinerescenti-albis : tarsis mediocribus. 
Description. — Fur long, moderately soft ; general colour deep brown; sides of 
the body with a very obscure yellowish hue ; under parts dirty gray with a 
faint yellow tint. All the fur deep gray at the base ; the hairs of the upper 
part of the body obscurely annulated with yellowish brown near the apex, 
and dusky at the apex ; the longer hairs are black. Feet brownish, covered 
above with brown-white hairs ; tarsi short. Tail short, blackish above, 
brown-white beneath. Ears small, well clothed with hairs ; those on the 
