662 MURIDAZ—MUS 
one of Steele Elliott’s specimens and others collected in 1898 by 
Henry Evans, published a full description and figure of the animal, 
and established a new species, his JZ. murals, for its reception. He 
thought that this mouse was “of at least several hundred years’ 
standing at St Kilda,” and while realising that it was very closely 
allied to AZ. musculus, he thought it better to regard it, pending further 
research upon the status of the various described members of the 
group, as a full species rather than as a sub-species of musculus. In 
1906 Barrett-Hamilton (Azz. Scott. Nat. Hist., 2) described a further 
series of specimens collected by Waterston in June 1905. In the 
autumns (September and October) of 1910 and 1911 Eagle Clarke made 
another collection, and he described these specimens in 1914 (Azz. 
Scott. Nat. Hist., 127). 
The status of JZ. muralis has been discussed by various writers. 
Lydekker (/ze/d, 30th April 1904) and Winge (1908) regard it as no 
more than a local race, while Millais and Trouessart treat it as a sub- 
species of szsculus. Barrett-Hamilton (Proc. Zool, Soc., 1899, 81) thought 
that since this mouse was perfectly isolated, and not known to inter- 
grade with the parent form (ausculus), it had “as much claim to be 
accorded full specific rank as any other island species.” After examining 
all the European members of the genus, Miller came to the conclusion 
that mwralzs is sufficiently well differentiated to receive full specific 
rank. For reasons given above (p. 648), Miller’s view has been 
adopted here, although not without hesitation. 
If Miller’s decision to regard the wild forms of southern and central 
Europe (MZ. sfictlegus) and the island House Mice (JZ. murals and 
Jeroensis) as distinct species be really well founded, it is possible that 
these species represent a more ancient stock of House Mice indigenous 
to western Europe. The distribution of these forms is in favour of 
such a theory; and the large size of the jaw from the Kirkdale Cave 
(see p. 636), assuming that specimen to be of Pleistocene age and really 
referable to this genus, figured by Owen, could be explained by referring 
it to a forerunner of muralis. Our knowledge of the matter, however, 
is still far from sufficient to raise any such view above the rank of a 
mere hypothesis. ; 
Description:—In outward form J7. muralis agrees closely with 
musculus, but differs in being rather larger, and in having the tail and 
feet more robust. The width of the hind foot, measured across the 
bases of the outer toes, is about 4 mm., instead of 3-5 mm., as in 
musculus. 
In general colour the back is rather lighter than in ordinary 
specimens of szasculus, the bases of the hairs are slaty, and while most 
of them have sepia-brown tips, a certain proportion are rufous-tipped, 
and give the animal a grizzled appearance. The under parts are bright 
