480 MR W. WEST AND MR G. S. WEST ON ; 
gation of the alge. The material was in every case fairly rich, that from Loch Ruar~ 
being especially rich in Desmids and Diatoms. | 
14. Loch east of Cearnabhal, Lewis, Aug. 1903.—This was a small deep loch, about 
200 feet above sea-level, and situated amongst rocky bog-land. . 
15. Loch Cuthaig, Lewis, Aug. 1903.—A small loch among rocky and bogey land, 
about 200 feet above sea-level. The plankton contained many Desmids, the most 
abundant of which were forms of Arthrodesmus Incus (Bréb.), Hass., and Stawrastrum 
lunatum, Ralfs, var. planctonicum. 
16. Loch Fadaghoda, Lewis, Aug. 1903.—This loch is about 2 miles long, with a 
very irregular contour. It contains several rocky islands, and its margins are both 
rocky and bogey. The plankton was well investigated, and the material collected was 
the richest we have ever examined. The Desmids were in great quantity, and also in 
great variety. Many species of great rarity and interest occurred in abundance in this — 
plankton, and the investigation of this material has extended the geographical range of 
quite a number of Desmids. Stawrastrum Ophiura, Lund, and Sphexrocystis Schroeteru, 
% 
~ i 
Chod., were especially noticeable. 
17. Loch Langabhat, Lewis, Aug. 1903.—A loch about 8 miles in length and about 
200 feet above the sea-level. The plankton contained large numbers of Mallomonas 
caudata, lwanoft. 
18, 19, 20, 21, and 22. Lochs Rownebhall, an Sgath, Shubhaill, Stranabhat, and an 
Toman, Lewis, Aug. 1903.—These lochs are all of small size and are similarly situated, 
none being at an altitude of more than 300 feet above sea-level. The plankton obtained 
from them was of a somewhat uniform character, that from Loch Stranabhat being 
undoubtedly richer than the others. Loch an Sgath was remarkable for the great 
abundance of Rotifers. L. Roinebhall contained Mallomonas longiseta, Lemm., and — 
M. producta (Zach.), Iwanoff. 
23. Loch Diracleet, Harris, Aug. 1903.—A small loch south of Tarbert, with rocky - 
shores, and situated very little above sea-level. The plankton was characterised by the — 
great abundance of Stawrastrum jaculiferum, West. 4 
24. Loch a Mhorghan, Harris, Aug. 1903.—A small loch among the hills 5 
miles north of Tarbert; its altitude is 480 feet. The plankton had no distinguishing 
features, although Asterzonella gracillima, Heib., occurred in considerable quantity. 
25. Loch Laxadale, Harris, Aug. 1903.—This loch is about 15 miles in length, a 
quarter of a mile in breadth, and is 40 feet above sea-level. It is situated near Tarbert, 
in the midst of high rocky mountains. The plankton was somewhat varied in character, 
and contained an abundance of Staurastrum paradoxum, Meyen, and St. jaculiferum, 
West. Seven species of Rhizopods were observed in this plankton. LLEMMERMANN also 
records Mallomonas caudata, Iwanoff, and M. longiseta, Lemm. 
