THE FRESH- WATER LOCHS OF SCOTLAND. 377 
loch, and is of the same order as those stories invented to explain why 
the fox has a bushy tail and why the serpent crawls on his belly. 
Notes on the Biology of the Lochs in the Lochy District. 
By James Murray. 
There is little peculiarity in the biology of the large lakes in the 
basin, except in that of Loch Lochy. They co^ntain the ordinary fauna 
of great lakes of low temperature. Most of them were surveyed so 
early in the season that the water was little above the minimum winter 
temperature, and the summer Crustacea {Tlolopediuni, Leptodora, &c.) 
had not arrived. The smaller lochs were warmer, and some of those 
Crustacea were present. 
Loch Arkaig. — The plankton is almost exactly that typical of large 
lakes, with hardly any local peculiarity. The larva of Leptodora, 
which we have rarely found, was present. A few examples of the 
somewhat rare T^atona setifera were found. A few species of plankton- 
desmids, chiefly of the genus Staurastrum, occurred, but they were less 
conspicuous than in the lochs farther west. 
Tjoch Ijochij. — Though the situation of Loch Lochy is so similar to 
that of Loch Ness, and though the depth in the two lochs is comparable, 
the plankton of Loch Lochy offers a remarkable contrast to that of 
Loch Ness. In two different years when the lochs were examined, the 
plankton in Loch Lochy was found to be much richer. The quantity 
was many times greater, the species more numerous, but the special 
feature was the quantity and variety of the phytoplankton. Diatoms 
were very abundant. Tcdjellaria fenestrata, var. asterionelloides, was 
of more luxuriant growth than had been observed elsewhere, the 
colonies often making more than two complete turns of the spiral. 
The rare crustacean Opliryoxus gracilis (discovered in Britain in Loch 
Ness by Mr. D, J. Scourfield) was present. The heliozoon Glatlirulina, 
of frequent occurrence in our larger lakes, but usually as skeletons 
merely, was here abundant and alive, the majority of the examples 
having the pseudopodia fully extended. 
Lochan na li-Earha. — The fauna calls for little comment. Latona 
setifera was found in the west loch. Of the summer Crustacea, Holo- 
pedium was in both lochs, Leptodora only in the east loch, and 
Diaphanosoma hrachyurum only in the west loch. Desmids were 
conspicuous in both lochs, and included some species which we have 
not often found. 
Loch Laggan . — The plankton is quite ordinary, except that it is 
the only loch of the basin where we observed two species of Diaptomus. 
