;iWiS .lOHS. HOYK PKTKHSKN 



This species, wliich lias iu»t |)ic'vi(iusl\ hccii liniiKi in kHlniul or 

 tiie Vestmnnnaevjar, j?re\v on a roc-k l)i'iiealli a ImkI cliH" al a heij^ht of 

 abt. 50 m. Clcve and Van IleurcU re-^ard it as a brackish waler 

 species. 



Nanicnhv lincohtlæ C\. 



Navicula anglica Halls var. minuta (^1. CA. Syn. II. j). 22. 

 E. k-el. 12 1 - N. Icel. 1G9. 



Only (iead frustnles were found in bolh thc samples, and tlie In- 

 caiities are ol' such a naUire tlial tlie rruslules mav easily be sn|)|)()sed 

 to have been carried to tliem trom waler. Hence I eonsider it most 

 probable thai this form is nol well suiled for an aerial life. 



Navicula cincta (Ehrb.i Kiitz. Cl. Syn. II. p, 1(5. Van Heurek .Syn. 

 IM. Vil, li<<s. 13, 1 1. Van Heurck Types No. .S2. 



N. kel. 217, L. 219 - Vestmannaejjar L. 401, 403. L. 410. 



No donbt it occurs predominantiy in water (Østru]) 49 samples\ 

 The 5 localities in which I found it in leeland vere all very damp. The 

 species has been found both in fresh and brackish water. so it is not 

 |)ronouncedly halophilous. The 3 sani|)les from Ihe Veslmannaeyjar were 

 laken from rocks by the shore which could probably be reached by 

 the salt water spray in stormy weather, whilc the samples from N. Ice- 

 land were laken from the interior where the inlluence of salt water is 

 inconceivable. 



— — var. Heufleri (Grun.) Van Heurck. Cl. Syn. II, p. 10. Van Heurck 

 Syn. l'l. VII, li<<s. 12, 15. 



E. Icel. 41. 78 — N. Icel. L. 133. L. 135, 137. L. 138. 140, 252 - 

 N. \V. Icel. k. 204, k. 269 — W. kel. 321 -Veslmannaeyjar 400. k. 401, 

 k. 403. k. 4(18. 409. 



As previously pointed out fBoye Petersen 1915. p. 23i this varicty 

 is a pronounced lerreslrial form Østrup 1 sample from Iceland . Spe- 

 cimens corresponding to f. curUt Hoye P. were found in samples 133, 

 138. In several of thc localities mentioncd it was found livinj^ in j^rcat 

 (|uanlity on purely mineral {^round, thus esjiecially in sample 138, and 

 in less marked def^ree in samples 133, 137, 204. 209, and all Ihe samples 

 liom Ihe Veslmannaeyjar. Ilcnce it hardly recpiires an}' greal contenl of 

 or{^anic substances in the substratum. 



— — var. leptocephala l'>réb. Cl. Syn. 11. p. 17. Van Heurck Ty|)cs 

 No. 84. 



E. Icel. 7 — N. Icel. k. 133. 



Only dilfers from thc type by ils more linear form. Is hardly any 

 pronounced aerial form. 



