Fresh-water Algee, &e. By A. W. Bennett. 5 



DESMIDIEiE. 



Sphaerozosma pulchellum Rabh. 

 Hitherto, according to Dr. Cooke, not observed in Great Britain. 

 Docidimn granulatum BenD. (in Journ. R. Micr. Soc, 1887, 



p. 8). Occasional. 

 Gonatozygon Brebissonii dBy (?). Fig. 12. 



Cells perfectly straight, very long and slender, 24-30 times as 

 long as broad, 7*5 //, broad, 190-230 (jl long, very nearly uniform in 

 diameter throughout, with slightly dilated and truncate extremities, 

 and no constriction in the centre. Endochrome homogeneous, with a 

 single row of from 20-24 vesicles down the centre ; extremities and 

 small space in centre colourless. The whole clothed with short very 

 thickly-set spines or hairs. 



I am somewhat doubtful about this identification, as I only saw 

 the cells detached, and not united into filaments, and as also it was 

 not seen in conjugation. It differs also somewhat in size from the 

 description and figures, being longer and narrower. Bog pools, 

 Borrowdale ; occasional. 



Closterium rostratum Ehrb. 



„ lineatum Ehrb. 



„ setaceum Ehrb. Pool near Derwentwater. 

 [Micrasterias papillifera Breb.] 



The character given in text-books — " Frond bordered by a row 

 of minute granules " — is by no means accurate in all cases; as often 

 as not I find them scattered over the whole surface of the frond. 



Micrasterias angulosa Hantsch. 

 Euastrum humerosum Ralfs. 



„ Jenneri Arch. Frequent. 



„ rostratum Ralfs., var. cumbricum n. var. Fig. 13. 



About the size of the typical form, but narrower in proportion to 

 its length ; average length 45-50 fx, breadth 25 /j, ; the outline nearly 

 rectangular ; each segment with two rounded lobes, each projecting 

 about as far as the blunt terminal beak ; terminal lobe rather deeply 

 divided at the apex. A single large prominence near the centre of 

 each segment. Bog pools ; frequent. 



Cosmarium bioculatum Breb. 

 „ pygmseum Arch. 



„ Wittrockii Lund. Frequent. 



Cosmarium globosum Buln. Fig. 14. 

 Minute ; outline elliptical ; length 20-30 fi ; breadth 15-20 /x ; 

 segments sub-reniform ; sinus acute. Endochrome homogeneous, 

 without vesicles ; cell-wall not punctated. Bog pools ; frequent. 



Cosmarium quadrum Lund. 

 This fine species was found in one gathering only. 



