COSJJARIUM. 173 



ENGLAND. Pilmoor, X. Yorks ! 



WALES. Llyn-y-cwm-fEynon, and Llanrhwchwyn 

 near Llanwrst, Carnarvonshire ! 



SCOTLAND.- -Scotston Moor, Aberdeen (Roy Bissett). 

 West of Kirkwall, Orkneys ! Bressay, Shetlands ! 



Geogr. Distribution.- -Germany. Gralicia in Austria. 

 Poland. Sweden. Java (var.). Madagascar (var.). 

 Australia (var.). United States. 



The marginal granules of this species are acutely conical,, 

 whereas those in the centre of the semicells are flattened and 

 rounded. There is sometimes a slight indication of a central 

 tumour in the middle of each semicell. 



Var. minus Racib. (PI. LXXXI, figs. 4, 5.) 



C. trachypleuruiii Lund, b. minor Eacib. in Spraw. Kom. fizyj. Akad. 



Umiej. Krakow, xix, 1884, p. 11, t. 1, f. 5: Eacib. Noun. Desni. Polon. 



1885, p. 73 ; Liitkem. Desm. Attersees, 1893, p. 552 "var. minus ^ ; Eoy 



& Biss. Scott. Desm. 1894, p. 177, t. 1, f. 13; West & G-. S. West, Alg. 



N. Ireland, 1902, p. 38. 

 C. minus Eacib. Desmidyja Ciastonia, 1892, p. 374. 



Cells somewhat smaller and more compressed, semi- 

 cells more oblong, with the acute marginal granules 

 continued over the apex. 



Length 31-34*5 ^ ; breadth 26'5-o3 /u ; breadth of 

 isthmus 8 '5-1 2 ^ ; thickness 18' 5 20 ^. 



SCOTLAND.- -Marsh between Loch Kinnord and 

 Cambus O'May, Aberdeen; Durris, Kincardine (Roy ^ 

 Bissett) . 



IRELAND.- -Lough Gartan, Donegal ! 



Geogr. Distribution. Austria and Galicia. Poland. 



. Russia. Sweden. Australia (a form). 



165. Cosmarium isthmochondrum Nordst. 

 (PI. LXXXI, fig. 7.) 



Cosmarium isthmochondriim Nordst. Norges Desm. 1873, p. 12, t. 1, f . 2 ; 



Wille, Norges Ferskv. Alg. 1880, p. 27 ; Boldt, Siber. Chlorophy. 1885, 



p. 106; Cooke, Brit. Desni. 1887, p. 114, t. 41, f. 9; De Toui, Syll. Alg. 



1889, p. 1015 ; West, Alg. N. Wales, 1890, p. 290 ; Eoy & Biss. Scott. 



Desm. 1894, p. 104 ; Nordst, Index Desm. 1896, p. 149 ; West & GK S. 



West, Alga-fl. Yorks. 1900, p. 72 ; Alg. N. Ireland, 1902, p. 38 ; Borge, 



Beitriige Alg. Scliweden, 1906, p. 33. 

 ? C. suborbicuiare Wood in Proc. Acad. Nat. Sci. Philadelphia, 1869 



