I go West: Phytoplankton of Etiglish Lake District. 



■disposition ( var. asterionelloides) . A few specimens of Ceratium 

 hirundinella make their appearance. 



June 1908. — Water-temperature 8.3°C. (=47°F.). A 

 marked Asterionella-^ldinkion, A . gracillima reaching a maximum 

 greater than the Nov. -J an. maximum. Tabellaria fenestrata 

 var. asterionelloides fairly numerous, but Melosira granulata 

 quite disappeared. A few Desmids have appeared, and also 

 the first bits of Anahcena Lemmermannii. Plenty of Crustacea, 

 but all of one species — Bosmina longirostris. Rotifers becoming 

 evident. 



July 1908. — Water-temperature ii.6°C (=53°F.). A 

 Crustacean plankton, with a large amount of Bosmina longiros- 

 tris, Daphnia longispina, and Copepods. A few Desmids are 

 fairly evident, and also a thin species of Spirogyra. Ceratium 

 hirundinella quite common, and a few individuals of Ccelos- 

 phcerium. Masses of floating spores of Anahcena Lemmermannii. 

 Rotifers increasing in numbers. 



August 1908. — Water-temperature I2.7°C. (=55°F.). A 

 Crustacean plankton, with a gradually improving phytoplank- 

 ton. Desmids becoming numerous and Ceratium hirundinella 

 plentiful. Peridinium Willei abundant. Microcystis ceruginosa 

 occurred in the plankton-collections for this month, but 

 only a few specimens were seen. 



General Remarks upon the Periodicity. 



The first publication dealing with the periodicity of British 

 phytoplankton was by Fritsch, who recorded the results of a 

 somewhat incomplete series of collections made in the river 

 Thames.* The next publication was by Bachmann, who gave 

 an account of periodical collections made by Father Cyrill in 

 Loch Ness from July 1904 to May 1905.! 



In Windermere, the dominant constituents of the phyto- 

 plankton are Chlorophyceae and Diatoms, the Myxophyceae 

 never at any time being conspicuous. In all, 65 species have 

 been observed, of which 30 (or 46.1 per cent.) are Chlorophyceae, 

 23 (or 35.4 per cent.) Bacillarieae, 7 (or 10.7 per cent.) Myxo- 

 phycae, 3 (or 4.7 per cent.) Flagellata, and 2 (or 3.1 per cent.) 

 Peridinieae. 



* F. E. Fritsch, ' Further Obs. on the Phytoplankton of the K. Thames,' 

 Ann. Bot. XVII., Sept. 1903. 



f Bachmann, ' Vergleichende Studien iiber das Phytoplankton \ on 

 Seen Schottlands und der Schweiz,' Archiv. fiir Hydrobiol. u. Plankton- 

 kunde, III., 1907, pp. 85-88. 



Naturalist, 



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