92 
MAMMALS. 
66. Mus decumanus, Pallas. Brown Rat. 
Abundant, but for the most part confined to the coast districts, 
though occasionally found at some inland localities ; abun- 
dant on many islands off the coast, but quite absent from 
others. Handa is infested with them, and there is evidence 
also of their presence on the Badcall Islands. We found 
no trace of them on Bulgie Island, nor on Garbh Island. 
Abundant in Caithness. 
Family AEVICOLID.a:. 
67. Arvicola amphibius, (i.) Water Vole. 
Abundant both on the clear rapid limestone rivers of Assynt 
and on the more sluggish streams. The black variety is, in 
our opinion, more abundant than the brown in the west, 
and is at least equally common in the east, where it haunts 
every burn except those that are too rocky. This interest- 
ing species appears to thrive well amongst the rocky lime- 
stone formation, finding ready shelter in the innumerable 
cracks and passages through the rock, but we have not met 
with it in the very rocky burns of other formations. Mr. 
Ben. IST. Peach observed the black variety commonly in 
Durness. They are common also in Strath Shinary, through 
which the river Shinary flows into Loch Sand wood. The 
common vole is easily tamed, and makes a cleanly and 
interesting pet. 
Until lately Mr. Wm. Eeid believed there was only the brown 
variety, but a young angler, when out fishing in a small 
feeder of the Wick river, came upon a number of black 
ones, some of which he killed, and he gave Mr. Eeid the 
skin of one. A part of this skin sent by Mr. Eeid for our 
inspection does not appear quite so black as many others 
we have examined, but is much blacker than the pure brown 
