ii6 
The Scottish NaUcralist. 
On the Stirlingshire side^ except the Snaid which flows from Loch 
Arklet, there is no stream save the Endrick, which, with its tribu- 
tary, the Blane water, drains a great extent of country, and brings a 
large body of water into the loch. Salmon, sea-trout, and brown 
trout, are numerous throughout the entire course of the Endrick, 
and in the lower reaches pike, perch, roach, and tench, are also 
found. 
The Leven, which debouches at Balloch, holds all the fish com- 
mon to the loch (except, perhaps, the Powan), and, in addition-,- 
there are occasional shoals of Grey Mullet (Afugil Chelo ?) which 
come up with the tide as far as Dalquhurn. The extensive pollu- 
tion of this river has, however, much impaired its value, both as a 
fishing stream, and as a highway for the migratory Salmonidse from 
and to the sea. 
Loch Lomond is studded with numerous islands of considerable 
size and great beauty. These islands have an important bearing 
on the presence and abundance of fish, as on their western and 
northern sides they are fringed by extensive banks of boulders, 
brought down, doubtless, by ice from the western high lands. 
Similar deposits and banks of boulders are found all along the 
Stirlingshire side of the loch, whilst on the Dumbartonshire side, 
and on the eastern and southern faces of the islands, no such 
boulders exist ; the only exception being Inch Moin, which is little 
more than floating peat, and probably had no existence at the 
time the boulders were deposited. These banks are the favourite 
resort of the Salmonidie, to the almost entire exclusion of the 
coarse fish, which seem to prefer a muddy or sandy bottom. 
The visible supply of food for all these fish is very meagre. 
There are but few species of mollusca, and these are not numer- 
ous in individuals. After careful search I have only obtained 2 
Ancylus^ 2 Flanorbis, a Cyc/as, a Succinea, and the ubiquitous 
Lymncea peregra. The large Anatina has lately been found on 
cleaning out a reservoir at Balmaha, but, so far, has not been 
observed in the loch itself. 
Besides these mollusca there is a fair supply of small water 
beetles, marsh and caddis worms, planarise and entomostraca, but 
on the whole the supply does not seem adequate to the mainten- 
ance of such a numerous population. I am inclined to think that 
the younger and weaker fish pay a heavy toll to their stronger 
neighbours, and make up the deficit in the general commissariat. 
