308 
BATHYMETRICAL SURVEY OF 
Notes on the Biology of the Lochs of the Shin Basin. 
By James Murray. 
Collections of plankton were made in eight lochs of the basin. The 
lochs are mainly characterised by the presence of two northern species 
of Diaptomus {D. laciniatus and D. laticeps), besides the common 
D. gracilis^ and by the very numerous Desmids, many of which are of 
the western type. 
Each of the three species of Diaptomus was found in five lochs — 
D. gracilis in Lochs Shin, a’ Ghriama, Ailsh, Gorm Loch Mor, and 
Fiodhaig ; I>. laciniatus in Lochs Shin, a’ Ghriama, Merkland, Ailsh, and 
an Daimh; D. laticeps (or a related species) in Lochs a’ Ghriama, Ailsh, 
an Daimh, Gorm Loch Mor, and Fiodhaig. All three species occurred 
together only in two lochs (a’ Ghriama and Ailsh), while in all the 
other lochs, except Merkland and an Lagain, there were two species; 
in Loch Merkland D. laciniatus was the only species seen. D. laticeps 
was identified in Lochs a’ Ghriama and Ailsh; in Lochs an Daimh, 
Gorm Loch Mor, and Fiodhaig, a species of the same group occurred, 
but as only females or immature males were seen, it is not certain 
whether they were D. laticeps or the very closely related D. Wierzejshii. 
Among other Crustacea there is little to note — Holopedium was 
only seen in Lochs Shin and a’ Ghriama; Leptodora in Lochs Shin, 
a’ Ghriama, and an Daimh ; Sida in Loch a’ Ghriama only ; DiapTiano- 
soma in nearly all of the lochs. Nearly all the Daphnice of Loch 
Fiodhaig were males. 
Ilyocryptus acutifrons, G. O. Sars, was found in Loch Shin in 
August, 1903, being previously unrecorded for Great Britain. It was 
obtained in a shallow bay at the mouth of the Fiodhaig river. 
The Desmids of Loch Shin have been fully studied by Messrs. W. 
and G. S. West.'^ On the occasion of our visit the very great abundance, 
of individuals as well as species, was remarkable, exceeding anything 
that we had observed in other lochs. In Lochs a’ Ghriama and Merk- 
land the species were also very numerous, and on the whole the same as 
in Loch Shin. In Lochs Ailsh, an Daimh, and an Lagain, few Desmids 
were seen, but all had some of the western species. In Gorm Loch 
Mor and Loch Fiodhaig no Desmids were noted. 
Pelagic Botifera were abundant only in Lochs Shin, a’ Ghriama, and 
Ailsh ; in Loch Shin the plankton collections also included many 
littoral species, which must have been driven out by the stormy 
weather. Floscularia pelagica, Bousselet, was in Loch a^ Ghriama 
only. Skeletons of the Heliozoan, Glatlirulina elegans, were abundant 
in Lochs Shin and a’ Ghriama. 
* See Journ , Linn . Soc ., Bot ., vol. 35 , p. 519, 1903. 
