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Part III. — Sixteenth Annual Report 



collected here, and, curiously enough, our Diaptomus was not present 

 this time : Cyclops strenuus appeared to have taken its place, at least at 

 the time the gathering was collected. A Cyclops, whose identity was 

 somewhat doubtful, occurred here, and may form the subject of further 

 study. The total number of species of Crustacea observed in this 

 gathering was thirteen : six of these were Copepods, five Cladocera, and 

 there were two Ostracods. 



(3) Bressat. 



Loch of KirhaUster. 



The gathering from this loch was a small lot, but it contained a few 

 things of special interest : mention may be made of three of these. 

 Cyclops vernalis, Fischer, has apparently not been previously observed in 

 any gathering from the Shetland lochs. Canthocamptus cuspidatus, 

 Schmeil, is a somewhat rare species, for which there are few British 

 records, and it is interesting to find that in our last paper on the Shetland 

 lochs this Copepod is recorded from Setter Loch and Brough Loch, both 

 of which are also in Bressay. Zaus sjnnatus, Goodsir, was another of the 

 Copepods found in this gathering : this, being one of the marine species, 

 seems rather out of its element in the Bressay loch. Of course it was 

 quite possible for this little loch, situated as it is so near the sea, to be a 

 brackish-water loch, and in that case Zaus spinatus would not have been 

 so great a "stranger." That it is not a brackish- water loch, however, is 

 fairly evident from the organisms that live in it ; and these same organisms 

 are not in ordinary circumstances the associates of Zaus. The conclusion 

 of the matter is, that this Copepod, voluntarily or involuntarily, has 

 wandered from its own special haunts into the domicile of strangers. 

 The number of Entomostraca, exclusive of Zaus, obtained in the gathering 

 from this loch is eleven — seven Copepods and four Cladocera. 



(4) Lochs in Yell. 



Loch of Colvister. 



The gathering from Loch of Colvister contained a greater variety of 

 organisms than that from almost any other of the lochs examined during 

 the season. Cladocera especially were well represented, and included such 

 comparatively rare forms as Latona setifera, Drepanothrix dentata, and 

 Harporhynchus falcatus. Both male and female Bosmina longirostris 

 occurred here. The Entomostraca observed included six species of 

 Copepoda and ten species of Cladocera : no Ostracoda were noticed, but 

 there were a few water-mites, " water-boatmen," and insect larvae. 



Loch of Lumhister. 



Crustacea were moderately common in this gathering. There was a 

 considerable variety of species, but, with the exception of Gammarus 

 duebeni, only two groups — the Copepoda and Cladocera — were represented. 

 The number of species obtained was the same as in the gathering from 

 Loch of Colvister ; there was also the same number of Cladocera, but only 

 five species of Copepods. Latona setifera was noticed, but appeared to be 

 rare. It sometimes happens that a casual examination of a gathering, 

 when it has just been collected, presents less favourable results than those 

 afterwards obtained. This is due, partly at least, to the tendency of 

 certain organisms, when disturbed, to hide amongst the inorganic and 

 vegetable matter that is more or less unavoidably present in gatherings 

 collected with the hand-net. 



