IV.—THE INVERTEBRATE FAUNA OF THE INLAND WATERS 
OF SCOTLAND.—PART IV. By Tuomas Scort, F.L.S. 
In this Report on the invertebrate fauna of the inland waters of 
Scotland, I propose**o describe, first,—the results of a partial examination 
of Loch Tay in Perhshire; and second,—the results of the examination 
of tow-net gatherings and other material from certain Sutherlandshire 
lochs, collected, and forwarded to Dr Fulton, the Superintendant of 
Scientific Investigations, by W. S. Caine, Esq., M.P. 
1.—Locu Tay, PERTHSHIRE. 
Introductory. 
Loch Tay belongs to the Marquis of Breadalbane and is one of the best 
salmon lochs in Britain. 
The district about Loch Tay is known to botanists throughout the 
length and breadth of the land, as one of the richest in native alpine and 
sub-alpine plants, in the British Islands ; some of the rarest of our native 
ferns, mosses, lichens, as well as flowering plants, have been and may still 
be obtained among the gullies and rocky crevices about the summits of 
Ben Lawers and the neighbouring mountains, and every year people 
interested not only in the British flora but in other departments of 
natural history as well are frequent visitors in the district. 
Though Loch Tay and its surroundings are thus well known not only 
to the mere pleasure seeker but also to the naturalist, no systematic 
attempt has apparently been made hitherto to investigate the invertebrate 
fauna of the loch, and the present contribution towards that object may, 
therefore, be of interest. 
It was during a short visit to the beautiful and picturesque village of 
Kenmore, in September last year, that I had the privilege of making a 
partial investigation of this fine Perthshire loch. Owing to the limited 
time at my disposal I was only able to examine that portion of the east 
end of the loch extending from the East Bay where the steam-boat wharf 
is, westward to near Fernan. There are two islands at this end of the 
loch—the ‘ Ministers Island ’—which is little more than a cairn of stones ; 
and Aidan’s Isle or the Isle of Loch Tay.’ King Donald IV. was drowned 
somewhere in the vicinity of Aidan’s Isle; and here Sibylla—Alexander’s 
Queen—died, and was buried a.p. 1122. 
DerptH oF Locu Tay. 
I was unable from want of time to take soundings of the loch, but the 
following notes from a paper read at a meeting of the Royal Society of 
Edinburgh, February 20th, 1888, by Mr James 8. Grant Wilson of H.M. 
Geological Survey, may not be out of place. Mr Wilson’s paper 
described the results of a recent bathymetrical survey of the chief 
Perthshire lochs and their relation to the glaciation of the district, and 
was illustrated by a carefully prepared chart of the various lochs referred 
to.* In this paper Mr Wilson describes Loch Tay as being 144 miles in 
length by about # of a mile in average width; the surface level of the 
*This paper was published in the Scottish Geographical Magazine for May 1888. 
