4 BRITISH DESMIDIACE^l. 



Var. attenuatum Griitw. (PL LXV, fig. 6.) 



C. Holmiense Lund. var. attenuatum Gutw. Wahr. d. Prioritat, 1890, p. 



67 ; Flor. Glon. Okolic Lwowa, 1891, p. 43, t. 1, f . 18. 

 C. Holmiense Liind. var. integrum Liind. forma West, Alg\ Engi. Lake 



Distr. 1892, p. 724, t. 9, f. 12. 



Semicells strongly attenuated upwards, with a pro- 

 minent constriction below the apex ; apex narrower 

 than in var. inteqrum and very slightly triundulate. 



' v O f 



Side view of semicell more attenuated. Vertical view 

 often narrower with slightly produced poles. 



Length 52-60 /^ ; breadth 30-36 n ; breadth of apex 

 21-22 M; breadth of isthmus 16-22^; thickness 17*5- 

 29 n. 



ENGLAND.- -Brothers' AVater, Westmorland ! 



Geoyr. Distribution. Gralicia in Austria. 



This variety does not appear to be a very constant one, 

 and is connected by intermediate forms with var. integrum 

 Lurid. The sides of the semicells may be as in the latter 

 variety or they may be somewhat irregularly undulate. The 

 cells varv much in relative thicknes>. 



Var. undatum YTest & G. S. West. (PI. LXV, fig. 7.) 



C. Holmiense Lund. var. undatum West & G. S. West, New Brit. Fresh w. 

 Alg-. 1894, p. 5, t. 1, f. 12. 



Cells smaller than in the type, with truncate-pyra- 

 midate semicells and triundulate sides ; cell- wall very 

 delicately punctate. 



Length 56 /n ; breadth 34 /< ; breadth of isthmus. 

 13/u; thickness 27 ^. 



SCOTLAND.- -Glen Sliee, Perthshire! 



This variety should possibly be referred elsewhere. AVe 

 have only observed it once, and before removing it from C. 

 Holmiense we should like to examine further specimens. 



-The "var. minor Arch." referred to in Cooke's 

 ' British Desmids/ p. 97, and mentioned by Archer in c Micr. 

 Journ.' xvi, 1876, p. 344, is only a small form of the species 

 probably referable to var. integrum Lund. 



