of the Fishery Board for Scotland. 



257 



ail Ostracod. Diaptomus wierzejskiiy which, from its universal dis- 

 tribution in these lochs, might be called the Shetland Diaptomu.%" was 

 of course present. The somewhat rare Cantliocamptus hirticornis and 

 C. minutus were obtained in this f:;athering. This is only the second time 

 that Canthocamptus minutus has been observed in the lochs of Shetland. 

 Planorhis nautHpus, Limnfm pevpcira, and a few insects were also noticed. 



Loch of HoidUquey^ North Roe. 



This loch, from its occupying a somewhat peculiar position, might have 

 been expected to yield results more than usually interesting. Unfortunately 

 the parts likely to give the best results could not be reached when the 

 loch was visited. Ten species of Crustacea and a few insects were found 

 in the gathering from this loch of Houllsquey. The " Shetland 

 Diaptomus'^ was again present, and here Canthocamptus minutus was 

 also obtained. The Gammarus found was G. pulex. 



Loch of Benigarth, North Roe. 



Although invertebrates were numerous in the gathering from this 

 loch, the variety was not so great as in some of the others : six species 

 of Copepoda, three of Cladocera, two of Ostracoda, and a Gammarus {G. 

 duebeni) were the Crustaceans obtained. A number of insects were also 

 included in the gathering ; these may be identified later on. 



Moosa Water, North Roe. 



The physical conditions of this loch appear to be unfavourable to the 

 propagation of Entomostraca and other Crustacean species. Lochs with 

 bare rocky or gravelly shores are sometimes very unproductive as regard? 

 the micro-invertebrates. 



Mill or Ennis Loch. 



The gatherings collected here and in Moosa Water were put together 

 in the same bottle, as mentioned in the previous notes : this was done 

 because of the apparent scarcity of living creatures in both gatherings. 

 A careful examination of the contents of this bottle yielded only four 

 species of Crustacea — two of Copepoda and two of Cladocera — and a 

 very few insects. But it is no unusual thing for students of natural 

 history to meet with disappointments, just as other people meet with 

 them in daily life. 



Pettidale Water. 



In this gathering we again met with the "Shetland Diaptomus" (D. 

 loierzejskii). Its associates were two species of Cyclops (C. strenuus and 

 C. albidus), one Lynceid {Alonopsis elongata), a valve of Candona 

 Candida, and one or two specimens of Gammarus pulex. There were also 

 a few insects in the gathering. This loch, like the two last, is apparently 

 not a favourable habitat for Entomostraca. 



Innis Loch. 



This completes the series of Northmavine lochs examined last season. 

 Though of small dimensions, Innis Loch gave better results than some of 

 the others. Entomostraca were moderately common in the gathering 



