ON SCOTTISH FRESHWATER PLANKTON. 519 
ScoTtisH FREsHwaTER Pranxton.—No. I. By W. West, 
F.L.S., and G. S. West, M.A., F.L.S., Professor of Natural 
History at the Royal Agricultural College, Cirencester. 
(Puatrs 14-18.) 
[Read 18th June, 1903.] 
OonTEnTSs. 
Page 
T.—Introduction ..........ccecceee ececceeteeeeeeeeeecnecsaeetsertessanteesen nese 519 
1I.—Detailed Account of the Plankton of the Lochs investigated ......... 520 
TII.—Systematic Account of the most interesting Species found in the 
preceding Plankton Collections ...............cccceee sc eeeeeeeeeceeee tes 536 
TV.—Conclusions.........0....ccceeeceenee ceteec caste teneeeseeeeccesecseuneeteerecees 553 
I.—InrropuctTion. 
A CONSIDERABLE amount of work has been done at the phyto- 
plankton of the freshwaters of Western Europe and even of 
Africa, but up to the present little attempt has been made to 
investigate the freshwater plankton of the British Islands. 
The first paper dealing with this subject was a short description 
of some plankton from the Isle of Mull, published by Borge * in 
1897. Another and more comprehensive paper has dealt with 
the plankton of Lough Neagh, Lough Beg, and the Upper River 
Bannt. A “Preliminary Report on the Phytoplankton of the 
Thames” has also been recently published by Dr. Fritsch. These 
are the sole contributions to British freshwater phytoplankton 
up to this date. 
The present contribution deals with plankton-material collected 
from lochs in different parts of Scotland and the Outer Hebrides. 
By means of two successive grants obtained from the Royal 
Society during 1901 and 1902, we have been enabled to investi- 
gate the Alga-flora of large areas of Scotland, particularly of the 
north and north-west. The collections were very varied and 
* O. Borge. ‘ Algologiska Notiser: 4, Siisswasser-Plankton aus der Inseln 
Mull.” Botaniska Notiser, 1897. 
+t W. West & G.S. West. “A Contribution to the Freshwater Algx of the 
North of Ireland.” Trans. Roy. Irish Acad. xxxii. sect. B, part i., August 
1902. 
{ F. E. Fritsch. ‘“ Preliminary Report on the Phytoplankton of the Thames,” 
Ann. Bot. xvi., Sept. 1902. 
