38 
ZOOLOGY OF THE VOYAGE OF THE BEAGLE. 
5. Mus Musculus. 
Mus Musculus, Auctorum. 
Of this species, there are six specimens in Mr. Darwin’s collection ; two 
were found “ living in the short grass, near the summit of the Island of Ascension, 
where the climate is temperate.” — D. Two others were procured “ on a small, 
stony, and arid island, near Porto Pray a, the capital of St. Jago, in the Cape 
de Verde Islands, — climate very hot and dry. Excepting during the rainy season, 
which is of short duration, these little animals can never taste fresh water, nor 
does the island afford any succulent plant.” — D. A specimen was also pro- 
cured “ on a grassy cliff, on East Falkland Island, at the distance of a mile 
from any habitation. It is singular that so delicate an animal should be able 
to subsist under the cold, and extremely humid climate, of the Falkland Islands, 
and on its unproductive soil.” — D. These specimens are all of them rather less 
than full grown individuals of the same species procured in England ; in other 
respects, they do not differ. 
The sixth specimen, which is from Maldonado, is considerably less than 
British specimens of the common mouse, and is of a richer and brighter colour, 
the head is smaller, the muzzle shorter in proportion, whilst the tarsi are even longer 
than in a large specimen of M. Musculus. These points of dissimilarity induced 
me to believe it was a distinct species, and to apply to it the specific name of 
brevirostris .* Upon re-examination, with the advantage of more experience, 
and consequently a better knowledge of the characters of these animals, I have 
changed my opinion. The teeth indicate that it is not an adult specimen, and 
agree perfectly with Those of M. Musculus , both in form and size. “ Common 
in the houses of the town of Maldonado, and its habits are similar to those of 
Mus Musculus — D. 
See Proceedings of the Zoological Society for February 14th, 1837, p. 19. 
