BIOLOGY OF THE SCOTTISH LOCHS 
313 
PART n 
CENSUS OF THE SPECIES 
MoUusca. — No study of the shells has yet been made by the 
Lake Survey. Information will be found in Dr Scott's papers. A 
few species only were noted. 
1. Limncea peregra (Mull.). Common. 
2. L. ovata (Drap.). {Teste Dr Wesenberg-Lund.) 
3. Planorhis contortiis (Miill.). Abban Water {teste Dr Lund). 
4. Ancyclus jiuv'iatilis^ L. Common. 
5. Pisidkmn pusillum (Gmel.). {Teste J. W. Taylor.) In the 
bottom muds down to 750 feet. 
6. Anodonta cygnea (L.). Common, especially in Lowland lochs. 
7. Unio margaritifer (L.). Common in the large Highland lochs. 
Hydrachnida. — The Water-Mites of the Scottish Lochs have not 
been adequately studied. A few species have been named by Mr 
C. D. Soar and Mr Wm. Williamson, but these represent so few lochs 
that nothing can be said as to distribution. Mr Williamson found 
that the common species in all the collections from Orkney was 
Huitfeldtia rectipes (Thor.), a species not previously recorded for 
Britain, and indeed unknown save in Norway. Dr Johnston found 
the larvae of a Mite alive, in great numbers, in the stomach of a trout. 
8. Ataa^ crassipes (Miill.). Common. 
9. Fiona ohturhans^ Pierzig. Loch Rannoch 
10. P. paucipora^ Thor. Loch Rannoch ^, Loch Laidon. 
11. P. fuscatus^ Herm. Dubh Lochan. 
12. P. earned^ Koch. Perth and Sutherland. 
13. P. rufa^ Koch. Sutherland. 
14. P. aduncopalpis^ Herm. Loch I^anagan. 
15. Pionacercus^ sp. Loch Rannoch. 
16. Oxtis ovalis^ Miill. Loch Rannoch. 
17. Hygrohates longipcdpis^ Herm. Common. 
18. H. reticidatus, Kram. Loch Ness, Loch Morar. 
19. Hydrochoi^ejites ungulatus^ Koch. Dubh Lochan. 
20. H. l^rameri^ Pier. Loch Ness. 
21. Lehertea porosa^ Thor. Loch Ness. 
22. Hydrachna globosa, De Geer. Common. 
23. Huitfeldtia rectipes (Thor.). Common in Orkney. 
24. Arrhenurus^ sp. St Mary's Loch. 
Tardigrada. — Of the 41 species of Tardigrada recorded for Scot- 
land, 30 have been found in the lochs. Since the publication of the 
