of the Fishery Board for Scotland. 



239 



M6r is Loch na Doirlinn, which is considerably smaller and shallower 

 than the other ; while still farther to the west is the third loch. The 

 overflow water from this loch drains into Loch na Doirlinn, but Loch na 

 Doirlinn and Loch M6r have separate effluents, which unite before reach- 

 ing the sea. Though, as already stated, we found the water of these lochs 

 quite fresh to the taste, yet in the two larger ones, swarms of Mysis vul- 

 garis were observed swimming about over the shallow sandy bottom and 

 quite close to the shore, and numbers of them were caught by the hand-net. 

 The Gammams observed in these lochs, and in other lochs in Barra and 

 North Uist, appear all to belong to the form described in Prof. G. O. Sars' 

 Crustacea of Norway as Gammarus duabeni, Lilljeborg ; the inner ramus of 

 the last pair of uropoda is considerably shorter than the outer ramus, and 

 the telson, uropods, and dorsal surface of urosome have a dense covering of 

 strong hairs. Among the Copepoda observed in these lochs is a Cantho- 

 camptus apparently new to science — it is described and figured at the end 

 of this report. The same species of Canthocamptus was subsequently 

 obtained in a number of other localities in Barra, in North Uist, and in 

 Shetland, and also near the head of Loch Tarbert. In these lochs there 

 was also a greater variety of Ostracoda than was observed anywhere else 

 in Barra or North Uist, and included among them was the somewhat 

 rare Darwinula Stevensoni. 



The total numbers of species of Mollusca and Crustacea obtained and 

 identified in the gatherings from the three lochs just described are as 

 follow : — Loch M(5r, — six species of Mollusca, one of Schizopoda, one of 

 Amphipoda, seven of Copepoda, nine of Ostracoda, and only one species 

 of Cladocera. Loch na Doirlinn, — three species of Mollusca, one of 

 Schizopoda, one of Amphipoda, five of Copepoda, six of Ostracoda, and 

 three of Cladocera. Small Loch West of Loch na Doirlinn, — one species 

 of Amphipoda, five of Copepoda, three of Ostracoda, and eleven of 

 Cladocera. The names of all the species are given in the Table of 

 Distribution (Table I.). 



Looh Benloden. 



This loch occupies a hollow on the south side and near the summit of 

 the mass of the high rocky land called Ben Tangaval, already referred 

 to, which forms the south-west corner of the Island of Barra. The 

 altitude of Loch Benloden is about 750 feet above the level of the sea. 

 Access to it is somewhat difficult, owing to the rough nature of the ground 

 that has to be traversed to reach it. The surroundings of the loch con- 

 sist largely of peat moss, and the variety of Crustacean life was not very 

 great, — three species of Copepoda (including Ophiocamptus sarsi, Mrazek) 

 and seven species of Cladocera, were the only Crustacea observed. 



Loch Cadha M6r and Pools near the Summit op Ben Heaval. 



I have placed these two together, as they are comparatively near to 

 each other and were visited on the same day. Loch Cadha M6r is 

 situated among the hills that rise immadiately behind the village of Castle- 

 bay. Part of the water used for domestic purposes in Castlebay comes 

 from this loch, and the following reference to the means adopted to obtain 

 the water may be of interest. The loch occupies a natural hollow among 

 the rocky uplands, rocky ground rises above the loch all round except at 

 the north end, and the natural course for the overflow water is from 

 this end away down the valley to the west coast, and therefore out of 



