§22 MR. W. WEST AND PROF. G. 8S. WEST ON 
Loch Nan Eun, Loch Skealtur, N. Uist, Outer Hebrides. 
The material was collected in very stormy weather in August 
1902, by allowing a large volume of water to pass through silk 
nets. 
Loch Nan Eun, which is about two miles in length and very 
little above sea-level, has both rocky and peaty surroundings. 
The plankton contained the following Rhizopods :—Arcella 
vulgaris (gigantic form), Difflugia pyriformis, Euglypha alveolata, 
Sphenoderia lenta, and Trinema enchelys. The Rotifer Notholca 
longispina was also in abundance. It was the richest plankton 
we have examined for Desmids. 
Loch Skealtur is not more than half a mile in length, and is 
very little above sea-level; its surroundings are both rocky and 
peaty. The following Rhizopods were abundant in the plank- 
ton :—Difflugia pyriformis, Centropyxis aculeata, Euglypha 
ciliata, and Cyphoderia Ampulla. 
Loch a Bhursta, Benbecula, Outer Hebrides. 
This is a small loch situated towards the centre of the island 
amidst surroundings of rock and peat. It is not more than half 
a mile in length, and the material was obtained by passing a 
large volume of water through the nets. The collections were 
made in August 1902. 
Loch Tay, Loch Katrine, Loch Achray, Perthshire. 
Loch Tay is about twelve miles long and 290 ft. above sea-level ; 
it is situated in proximity to high mountains which reach an 
altitude of 4000 ft. The opportunity thoroughly to investigate 
this loch did not occur, and the plankton-collections were made 
in July 1902 from near the head of the loch *. 
Loch Katrine is about seven or eight miles long and 364 ft. 
above sea-level; it lies in the midst of mountains from 2000- 
3000 ft. high. The plankton was obtained from the outlet of 
the loch in April 1903. 
Loch Acbray is a little more than a mile in length and 276 ft. 
above sea-level. It receives its water from Loch Katrine, which 
is only a mile and a quarter distant. The plankton was obtained 
over the deeper parts of the loch, in April 1903, and is very 
similar to that obtained from Loch Katrine. 
* [Since the above was written, further plankton collections have been made 
in July 1903.—G. 8. W., 3rd Sept., 1903.] 
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