142 BATHYMETRICAL SURVEY OF 



colour), Ceratium hirundinella, Asplanchna, Anurcea cochleare, 

 Anabcena were among the most abundant organisms. Many others 

 were present in smaller numbers. 



Drummond Pond. This is a shallow and nearly stagnant artificial 

 pond, and many species were plentiful in the water. Daphnia 

 lacustris was most numerous. Many males and females carrying 

 ephippia were present. Other abundant species were Ceriodaphnia 

 (some with ephippia), Anurcea cochleare, Conochilus, Asplanchna, 

 Notops pygmceus. Volvox was scarce. The beautiful Rhizopod Difflugia 

 corona was seen. 



The lochs of Strath Bran, though completely isolated one from 

 another, and draining by different streams into the Bran, are fairly 

 comparable one with another, being all, with the exception of Loch 

 Freuchie, hill lochs of small size, lying at considerable elevations. 



Loch Freuchie. This was one of the lochs where Holopedium for 

 the time being abounded to the exclusion of everything else. Only a 

 few individuals of Diaptomus gracilis (brown in colour) were seen. 

 Hardly any small organisms were noticed. 



Loch Fender. Life was abundant, but few species were present. 

 The most numerous animals were Diaptomus (pale brown), Notholca 

 longispina, Daphnia (parrot-shaped head), Bosmina longispina, and 

 Peridinium tdbulatum. Holopedium was not seen. 



Loch Hoil.- Life was very abundant. The commonest animals were 

 Holopedium, Diaptomus gracilis, D. Wierzejskii (blue, red, or red and 

 blue), Daphnia, and Asplanchna. 



Loch na Craige. Animals of many species were present, but only 

 four were plentiful Diaptomus gracilis (blood-red), Bosmina ob- 

 tusirostris (of large size), Daphnia lacustris (very large), and Conochilus 

 unicornis. 



Loch Kennard. Some seven or eight species of animals were 

 common in the loch, but Diaptomus predominated. D. gracilis and 

 D. Wierzejskii were both present. Blood-red individuals of both species 

 occurred, and D. Wierzejskii was also seen of the usual blue colour, or 

 red and blue. Holopedium, Notholca longispina, and Asplanchna 

 priodonta, and the somewhat rare crustacean Latona setifera, were 

 numerous. 



Loch Skiach. The characteristic animals were Holopedium, 

 Daphnia lacustris (very large), Bosmina obtusirostris (very small, 

 purple). Gammarus pulex of large size, and orange colour, was found. 

 A few examples of Bosmina were large and brightly coloured, orange 

 and purple. 



Loch Tay. Comparing Loch Tay with Loch Rannoch, it is found 

 that the plankton differs in several important particulars. Besides the 

 common Diaptomus gracilix, there was another species, D. Wierzejtkii , 



