IVes^ : Phytcplankton of English Lake District. 267 



This Alga occurred in a more or less fragmentary condition, 

 in the plankton of Codale, Easedale, and Stickle Tarns. It 

 was obviously merely washed in from the shores, and has there- 

 fore been excluded from the table of phytoplankton. It is 

 not uncommon at the margins of subalpine tarns and lakes, 

 especially if boggy, but is not always easy of recognition. 

 The filaments are from 6-9 \i. in diameter. 



2. GoNATOZYGON MONOT.ENIUM De Bary var. pilosellum 

 Nordst. in Wittr. & Nordst. Alg. Exsic. 1886, No. 750 ; fasc. 

 21, 1889, p. 48. 



This rare variety has not previously been recorded for 

 England. It is well characterized by the short spinate pro- 

 jections which replace the minute granules of the type form. 

 The cells were 9-1 1 ju. in diameter, and in this variet}^ they are 

 generally somewhat narrower than in the type, with slightly 

 less dilated extremities. We have recorded it from the plankton 

 of Loch Fadaghoda in the Outer Hebrides, and we have found 

 it in other localities in Wales and Ireland. 



3. Cylindrocystis diplospora Lund. var. major West in 

 ' Journ. Linn. Soc. Bot.', XXIX., 1892, p. 131, t. 20, f. 3 ; 

 W. & G. |S. West in ' Journ. Roy. Micr. Soc.', 1894, p. 4, t. i, 

 f . 9 ; ' Monogr. Brit. Desm.' I., 1904, p. 61, t. 4. f. 42, 43. 



This large variety was not uncommon in the plankton 

 of Ennerdale Water. Long 125 ju. ; lat. 62 /x. It is known to 

 occur in several British localities, and the first English record 

 was from Riccall Common in East Yorkshire. 



4. MiCRASTERiAS PiNNATiFiDA (Kiitz.) Ralfs, ' Brit. Desm.', 

 1848, p. 77, t. 10, f. 3 ; W. & G. S. West, ' Monogr, Brit. 

 Desm.', II., 1905, p. 80, t. 41, f. 7-11, 13. 



This pretty little species is known to occur in the bogs of 

 the Windermere drainage basin, and we have observed it 

 sparingly in the plankton of Ennerdale Water. It appears to 

 be confined to the old formations of the western mountainous 

 areas of the British Islands ; and in parts of the west of Ireland 

 and north-west Scotland it is frequent in the bogs and lakes. 



5. MiCRASTERiAS RADiATA Hass. ' Brit. Freshw. Alg.', 1845' 

 p. 386, t. 90, f. 2 [figure bad] ; W. & G. S. West, 1. c, p. 113, 

 t. 51, f. 1-9. M. furcata Ralfs and other authors. 



Like the preceding species M. radiata is one of the western 

 types of the old formations. It occurred in the plankton of 

 Easedale Tarn, this being the first English record. Long. 187 /x ; 

 lat. lyo fi ; lat. isthm. 23/7,. 



1909 July I (To be continued). 



