12 BRITISH DESMIDIACE^. 



C. ochthodes var. amoebo-granulosum Schmidle, Alg. Bern. Alp. 1894, p. 



92, t. 6, f . 9. 

 C. speciosum Lund. var. australianum Nordst. forma Gutw. Flor. Glon. 



Okolic Lwowa, 1891, p. 50, t. 1, f. 35 a t. 2, f. 35 b. \_ = C. ochthodes 



var. amcebum according to Gutwinski, 1895.] 



Semicells pyramidate-trapeziform, with broader 

 apices than in the type, margins only faintly undulate ; 

 warts very broad and flat, scarcely elevated, and sinuous 

 in outline ; cell- wall between the warts sparsely punc- 

 tate. 



Length 87-90 ^ ; breadth 60-67 /x ; breadth of apex 

 25-27 p. ; breadth of isthmus 21 /x ; thickness 40 p.. 



ENGLAND.- -Foot of Brant Fell, Westmoreland 1 

 Hampsfell and Hawkshead, Lancashire ! Mickle and 

 Cronkley Fells, N. Yorks ! 



SCOTLAND.- -S utherland ! Skye in Inverness ! Hoy, 

 Orkneys ! Near Scalloway and Bressay, Shetlands ! 



IRELAND.- -Lough Grartan, Donegal! Bog near Lough 

 Neagh, Londonderry ! 



Geoyr. Distribution. Austria and Galicia. Switzer- 

 land. Lapland. Spitzbergen. 



This variety is about the same in size as the type, but the 

 semicells are more trapeziform, possessing broader apices. 

 The outline is but faintly undulate (much less undulate than 

 in the type), and the greatly depressed warts are very broad 

 towards the centre of the semicells. They are of almost in- 

 appreciable elevation and sinuous in outline (hence the varietal 

 name " umicbum "). 



We sometimes find this variety and the type abundantly 

 in the same collection, in which case the differences stand 

 out most clearly. They can always be distinguished by out- 

 ward form alone, although the character of the cell-margin 

 and the sinuous "warts' are the principal features of the 

 variety. 



Var. subeirculare Wille. (PI. XCVIII, fig. 7.) 



C. ochthodes var. subeirculare Wille, Norges Ferskv. Alg, 1870, p. 26, t. 1, 

 f. S ; G. S. West, Alg-a-fl. Cambr. 1899, p. 219; West & G. S. West, 

 1900, p. 8-4 ; Wille, Algolog. Notiz. VII. 1901, p. 17. 



Cells smaller than in the type, only a little longer 

 than broad ; semicells subsemicircular, margins uni- 

 formly undulate, and within the margins with 3 



, o 



