THE BRITISH WATER RAT 479 
(Celtic) :—Scottish Gaelic—radan-uisge =“ water rat” (C. H. Alston); 
lamhalan, perhaps from famh-alan = “water mole.” Welsh—/lygoden 
y dwfr= “water rat” (Forrest). 
In general appearance and characters the British Water Rat is 
typical of the genus Avvzco/a , in size it is larger than other European 
species, excepting A. sapzdus. The tail is somewhat more than half as 
long as the head and body. As compared with Epzmys norvegicus it 
has the body heavier and more robust, the tail relatively shorter, and the 
head distinctly more rounded. Although the ears (Pl. XXVL., Fig. 1) 
are well developed, they are inconspicuous, barely show above the fur, 
and when laid forward hardly reach half-way to the eyes. They are 
on both surfaces thinly clothed with rather long hairs, subcircular in 
outline, and with well-developed, bluntly triangular, naked meatal valves. 
The small eyes lie about half-way between the ears and the muzzle. 
The nostril-pad is small and naked, its lower border continuous with 
the naked median groove of the upper lip. The upper incisors project 
slightly when the mouth is closed. 
The hands are broad and robust, but not specialised in any particular 
direction ; the rudimentary thumbs are smaller than the smallest palmar 
pads, but carry distinct nails covering their dorsal surfaces; digit three 
is longest, slightly exceeding four, as four does two, five reaching about to 
the base of four; all the digits are scaled on their under surfaces, and 
carry slender slightly curved claws, equal in length to about one-quarter 
of their digit. 
The feet are large and slightly fringed, apparently for swimming ; 
of the digits the first is smallest, reaching about. half-way to the base 
of the second; the second, third, fourth, and fifth are much as in the 
hand, as are the scales and claws, the latter, however, stronger than in 
the hand ; except for a slight sprinkling of hairs on the posterior third, 
the soles are naked. The pads are variable both in size, and, 
sometimes, in number, being evidently in course of reduction. As a 
rule they are comparatively small, and the small internal proximal one 
appears only as a smooth spot, so that the total is normally five, 
but occasionally six are present. In one specimen the feet 
showed a confused mass of tumid flesh without true differentiation 
into pads. 
The tail tapers noticeably from a thick base; when laid forward it 
reaches about to the shoulders or slightly beyond; the annulations are 
irregular, but clearly visible and not concealed by the hairs—about 15 
to the centimetre at the middle of the tail. The numerous hairs are 4 to 
5 mm. long and form a slight terminal tuft. 
The mamme are as in Mzcrotus. 
There are on the flanks, about half-way between the root of the tail 
and the scapule, paired vascular glands, oval in structure (17 x 12 mm. 
