MUS HIBERNICUS RESTORED TO THE BRITISH FAUNA. 205 
2nd. The fur is finer in texture, and silky to the touch. In 
this respect it is even finer than M. rattus, and affords marked 
contrast to the rough and somewhat harsh coat of M. decwmanus. 
3rd. In the general colour of the fur, and its constancy in 
shade. 
4th. In its peculiar and circumscribed distribution. This 
singularly limited and isolated western range, in which it has 
been so long known to exist in some numbers, is most remarkable 
and important, and, taken together with the fact that it does not 
appear to have been recorded for the mainland of Great Britain, 
nor from Europe, affords weighty evidence against M. hibernicus 
being regarded as of varietal value only. 
The following table shows the comparative measurements of 
M. hibernicus and M. decumanus, and are taken from specimens 
while in the flesh :— 


Mus hibernicus. Mus decumanus. 
peal Female. Male. Female. 
iene}! Matas wri Gane Uren) re in 
Length of head and Pad 8 la WAR dealt 3 Sead S| ieee eels 
» of head . a Was of. Are (0s 902 4) 2 Of 
PROMORTS) | ots hy rete OF, 8h Oy Deh Oy LOS} AO, 29 
» of tail ‘Ge so {iS ss eis te = cad 
», of fore feet ane okies Om a (Visnhal’, ()al{ 0 10 
» Of hind feet and claws le “a ERS Way 7 IPSS 

Desoription.—The fur is glossy. The hairs on the back are 
of two kinds—a longer, which is white at the roots and darkens 
gradually to the tips, which are black; and under this a shorter 
fur, of an ashy grey colour. The general colour of the upper 
surface is dark silvery grey, almost black. This shades into a 
paler tint on the sides. The under surface and limbs silvery 
mouse-grey. The head is slightly browner than the back, with the 
muzzle mouse-grey. The digits silvery white. The white stripe, 
regarded as the important diagnostic character by Thompson, 
does not possess that value. In both Hebridean and Irish 
examples examined by me, the specimens wanting the stripe 
have been as numerous as those possessing it, so that it may be 
commoner to this than to M. rattus and M. decwmanus, in both 
of which it is said occasionally to occur. When present in Mus 
