THE SKOMER BANK MOUSE 421 
In 1898 I became aware of the existence of the Skomer Bank Mouse. 
In October of that year Marsden sent me two taken by Mills, to which 
Mills afterwards added ten more. These remained in my collection 
until the publication in 1900 of Miller’s “ Preliminary Revision of the 
European Red-backed Mice” (Proc. Wash. Acad. Sct., 26th July 1900, 
83-109). This suggested a re-examination of the Skomer specimens, 
with the result that in 1906 I described the new British Mammal 
and definitely assigned it a place amongst other related forms of 
neighbouring countries. It is clear that to Drane belongs the honour 
of discovering this species (see Proger, Feld, 20th Feb. 1904, 321 ; 
Thomas, F7ze/d, 12th March 1904, 451), but, that, without Miller’s paper, 
Drane’s discovery was meaningless and its value could not be recognised. 
Status :—F. skomerenszs belongs to a group of European bank mice, 
characterised by size larger than that of g/areo/us, and distributed in 
isolated colonies, on mountains or islands. These are comparable to 
the two continental forms of Lepuws ¢2mzdus, and may logically be treated 
as sub-species of one central form, &. wagerz (Schinz, 1845). The 
meaning of this group is shown by Hinton’s determination of a closely 
allied form or forms from the late Pleistocene of Ightham, Kent; Brix- 
ham, Devonshire; and St Lawrence, Isle of Wight. This paleontological 
evidence and the characters of skomerensts indicate that the latter 
is a somewhat modified survivor from an older fauna, which has 
been everywhere driven out by the newer and more recent arrival, 
glareolus; the remains of this last occur for the first time in Britain 
in the Pleistocene of Ightham, alongside those of the then existing 
member of the older group. The reality of the group is not invali- 
dated by the fact that one of its forms, 2. wagerd, intergrades with 
E. glareolus through the sub-species Z. 2. helveticus. The large and 
small forms still remain distinct in origin. As in the case of Lepus, 
isolated members of the group have become so far differentiated as 
to have attained specific rank; and indeed it is only a matter of 
convenience whether such geographically isolated forms as norvegicus 
and zager? be given the superior or the inferior grade. The following 
are the known forms, excluding /. a/stonz and E. erica of Scotland, 
described below :— 
E. nageri norvegicus (Miller) of western Norway, and north at least 
to Nordland, has a broad mantle not sharply defined from the buffy- 
grey flanks, the hind foot 18-4 to 19, a heavily built skull, the condylo- 
basal length of which is 24:2 to 26-2 mm., and 7* has usually three 
internal infolds. &. 2. vasconze (Miller), of the French side of the 
Pyrenees, is very similar to the last, but perhaps larger, and with a 
duller, narrower mantle and less buffy sides. Z. 2. nageré (Schinz) 
of the Alps and the northern Italian mountains, is slightly larger than 
E. n. norvegicus (hind foot, 18-8 to 20; condylo-basal length of skull, 
