400 .ions. uovi PKiiusKN 



Navicula radiosa Kiil/.. Cl. Svii. II. p. 17. \'an llciircU Svn. PI. \'1I, 

 fig. 20. 



N. Icfl. ICl). 



Tilis verv coinmoii Iresh wiiter species (Ø.slrii|) 28(5 samjiles can 

 hnnily llirivc on hind. and as a nialtcr of lad I loiind no specimens 

 \villi coll contcnts in tlic saiiijile. 



— — V. minutissima (iriin. (".I. Syn. 11, \). 17 



K. Icel. 125. 



The specinicn found had llu' f'ollowinj^ dimensions: L. 20 //, br. 3.3 /<, 

 slr.l8 in 10/<,being tliiis in close agreement w itli (>leve"s description (,l.c.). 



var. tenella (Bréb. Van Heiirck. CI. Syn. 11. p. 17. V. H. 



Syn. PI. VII. lig. 21-22. V. H. Types No. 1U7. 



Vestmannaevjar L. 399. 



Tilis variety conies vcry near lo A'. ciiicla var. (uiri. In lacl, I am 

 nol sure thai they can be kepl dislinct. According lo Cleve and olher 

 authors it is a form tliat Ihrivcs in (|uile fresh water. On the Vest- 

 mannaevjar I found il in considerable (pianlily in a rocky cave at a 

 heiglit of 2ii m. Therc was jilenly of moisturc iircscnl, so Ihal ils oc- 

 currence in Ibis place does nol warrant Ihe assumplion thai it is a pro- 

 nounced acrial species. 



Navicula viridula l\ulz. CI. Svn. II. p. 15. Van Heurck Svn. PI. VII, 

 fig. 25. 



N. Icel. 135? 



Only a single specimen was observed. Ils dimensions were: L. 79//, 

 br. 15 //. str. 8 in 10 //. 



Pinnninria Ehrb. 



Pinnularia appendiculata Ag. (^I. Syn. II. |). 75 Van Heurck Syn. 

 PI. VI, lig. IN and 20. 



H. Iccl. 123 - .\. Icel. 217 - W. Iccl. L. 338 — S. Icel. 295. 



Tilis sjiecies bas long been known to bc babilual among niosses, 

 on damjj rocks, and in similar jilaces (]1. 1, c). Østrup found it in 

 Iceland in 19 sam|)lcs from fresh water, hcnce it must be infcrrcd thai 

 it is no pronounced aerial alga. Il was comnion in sample 338 wliich 

 was from llic soli of a potato lield near tlu' hot sjirings by flelgavatn. 



— — var budensis (irun. (^I. Syn. 11, p. 75. Van Heurck Syn. 

 PI VI. f]<». 27. 28. 



N. kel. L. 133, 25(5. 



This variely is chielly known from hol springs. Østrup found it 

 in Iceland in 3 samples, 2 of whicli were from hol springs. None of the 

 2 samples in which I observed it wasderived from the vicinily of hol springs. 



