219 



108. E. rostratum Ralfs. 



Rostrup mentions having found this species in Tårn on (ilivers- 

 rejn« (Str.). 



109. E. elegans (Bréb.) Kiitz. 



A watercourse near Trangisvaag (Syd.); Sand (S an do); Klaksvig 

 (Bordo); Skjælling (Str.). 



Var. bidentata Niig. 



Nolso; Kirkcbokamp near Tliorshavn (Str.). 



110. E. binale (Turp.) Ralfs. 



Mentioned by Rostrup (Fær. Fl. p. 90); I found il in a gatliering 

 from Skjælling (Str.). 



Var. denticula Kirchn. 

 Moor near Hojvig (Str.). 



111. Cosmarium Cucumis Corda. 



This species which has already been found by Rostrup (Fær. Fl. 

 p. 90) and Wille (1. c. p. 27) is very commonlj^ distributed in the Færoes; 

 in the different localities it varies very much with regard to its size 

 and the outline of the cell. Most common are forms like Ralfs's fig. 2, 

 tab. 15 in Brit. Desm. ; but specimens very much like Nordstedt's figures 

 in Desm. arctoæ tab. 7, fig. 28 and 29 are also found. The latter 

 (formå major Nordst.) occurs rather high up in the mountains. In 

 gatherings from bare ston}^ ground near Trangisvaag (300 m.) and from 

 mountain heights on Bordd (450 m.); in the latter place mixed with some 

 Arctic Desmids. 



112. C. quadratum Ralfs. 



Met with by Rostrup (Fær. Fl. p. 90) in »Tårn on Gliversrejn« (Str.). 



I have found the following different forms : — 



A form like Ralfs's fig. 1 a (1. c. tab. 15). 



Trangi-svaag and Kvalbo (Syd.); Sand (Sando); Kirkebokamp near 

 Thorshavn (Str.). 



Formå »semicellulæ lateribus nonnunquam latissime rotundatis 

 1. rectis, nec retusis« W^ille Novaj. Semlj. p. 37, tab. 12, fig. 20; the 

 membrane, however, is thinner in the specimens from the Færoes. 



Kirkebokamp near Thorshavn (Str.). 



Formå major Wille 1. c. lig. 21. 

 Long. = 75;u; lat. = 38 ^m. 

 Grothusvatn (Sand 6). 



113. C. sinuosum Lund. formå genuina. 



Wille reports 1. c. p. 27) that this species seldom appeared in the 

 collections which he has examined. 



