The Mammals of Great Britain and Ireland
S U B -S P E C IE S I I I
T h e H e b r id e a n W oo d M o u s e
Mus sylvaticus hebridensis, W . E . d e Win ton .
Characters.—In general form and colour this sub-species resembles M. s.
intermedins, but it is larger and has proportionately smaller ears, larger hind feet
(especially in males), a shorter and thicker tail, and a generally stouter build. The
colour of the upper parts is more uniform and less bright than in M. s. intermedins.
The under parts, according to Mr. de Winton, are generally dusky or sandy, and
have no distinct line between the two surfaces, whilst the tail is o f uniform
brownish grey. Total length of skull 27 mm.
Captain Barrett-Hamilton has made1 the following interesting observations on
the pelage of immature examples: ‘ The young males appear to lose the dull hues
of immaturity of the upper side, and to don the reddish colour of maturity, at
an earlier age than do the females, so that young males and females of the same
age are actually distinguishable by their colour alone.’
D istribution.—This form of Mus sylvaticus was first obtained by Mr. J . Steele
Elliot and afterwards described by Mr. de Winton.2 It seems to be found only
in the islands of Lewis (North Harris) and Barra, in the Outer Hebrides.
SU B -SP E C IE S IV
T h e S t . K il d a W ood M o u s e
Mus sylvaticus hirtensis, G . E . H . B a r re tt-H am ilto n .3
Characters.—This Wood Mouse is closely allied to the M . s. hebridensis, from
which it differs in its ‘ slightly larger size and also in the greater amount of buff
or yellowish-brown coloration on the under side. Like M. s. hebridensis, it differs
from M. s. intermedins, apart from its greater size, in the more uniform coloration
of the upper surface of the body, in the absence of the clearly defined white
under side, and in the longer feet and shorter ears.’ The skull is unusually large,
1 Proc. Zool. Soc. 1900, p. 404.
■ Mm heiridemis, W. E. de Winton; Zoologist, October 1895, p. 369; Mus syluatiom M riia tsk, W. E. de Winton,
ibid. November 1895, p. 426.
8 Mus hirtensis, Barrett-Hamilton, Proc. Z00L Soc. 1899, p. 8 1 ; Mus sylvaticus hirtensis, Barrett-Hamilton, ibid. 1900,
p. 404.