ITS DISTINCTION FROM OTHERS. 371 
Mouse, or Field Vole (Arvicola agrestis, Fleming) 
especially as there is arough haired Mouse figured 
in Shaw’s Miscellany as a variety of that species. 
It is also well known that the Meadow Mouse is said 
tovary muchin size and colour in differentsituations. 
It must however be observed that although an 
occasional case does occur among the higher ver- 
tebrata of animals suffering not a little extent of 
variation, yet there are some marks which ought to 
be regarded as decisive of specific difference, and 
perhaps there are but few instances in which it is 
proper to rank the cases as “varieties” when the 
differences amount to more than latitude in size 
and colour. Accordingly I suspect that the animal 
figured by Shaw whether in reality similar to mine 
or not, is aspecies by itself, and with regard to the 
present specimen I proceed to enumerate those 
points of difference between it and the Meadow 
Mouse which | regard as establishing it a distinct 
kind. In the Meadow Mouse the legs are much 
shorter, and the bulk of the body more considerable ; 
in the Meadow Mouse there are on the fore feet 
three toes with claws and the thumb without a claw, 
while in this animal the thumb itself has a claw, 
and quite as large as the others; in the Meadow 
Mouse the bristles are shorter, and the muzzle blunter 
than in this species ; in the Meadow Mouse the fur 
is compact and short, while in this kind it is 
curiously lengthened, scanty, and lax, and makes it 
appear in some measure shaggy. With regard to 
dimensions of the head, body, and tail, and colour 
of the fur, nothing distinctive can be mentioned, 
from the liability on the part of the Meadow Mouse 
to vary in these respects. It is not improbable 
however that at some future time authors may agree 
to elevate these reputed varieties in size in that 
species to another rank, and so far as regards those 
found on the Continent, it is to be observed that 
Viv2 
