;ks4 



JOHS. BOYK PETEHSEN 



Caloneis fasciata v:ir elliptica n. v;n. 



Tlic valvc clli|)lic willi sli^htly radiatiiijf stria-. I, l.S/<, 

 br. 7//. sir. 23 in 10//. Inside tlie marj^in a ralliei- distincl 

 apical line is secn on eiliier side. Fig. 8. 



N. Icel. 215, 217. 



pjg g Both thc samples in wliicli this variety was foiind were 



Caloneis derived from llu' l)nsalt ravine Stora Gja on thc eastern side 

 f'ascinla of Mwatn in whicli a hot spring dehouchcs. One sample is 



(Laj^crst. Cl. f,.Q,^, Ihe surface ol' niiid, thus from a verv damp localitv. 



var. ellipticu , n .i • r i . i • i ' , 



n var ^vhcrcas the other is from a large stone which was covered 



(X 1200). \vith Prasiola crispa and mosses intermixed wilh smaller algæ. 



— — var. fonticola Grun.) 

 Van Heurck Syn. l'l. 12. fig. 32. 



N. Icel. 217 - W. Icel. 321. 



Navicula fonticula Grnn. 

 Fig. nostr. 9. 



In this variety tlie valve is slightly lanceolate wilh 

 parallel, or in the longer spccimens slightly radiating, stria- 

 tion. L. 17,6-20,9//, br. 4,5 //. str. 23 in 10//. 



The two samples in which it was found were both 

 derived from the vicinity of a hot spring, one of them 

 from the same large stone in Stora Gja where also var. 

 elliptica was found, the other from the ground beside the 

 oulflow from Skrilla* near Reykholt, where it was living 

 among Hepaticæ. 



Fi«.9. 



Caloneis 



fasciata 



(Lagerst. Cl. 



var. fonticola 



(Grun.) 



(X 1200) 



— — f. acuta n. f. 



The valve linear wilh cuneate jiointed apices. Apical area 

 most frequently rather broad. L. 17—22//, br. 4—5//, str. 23— 

 25 in 10//. Fig. 10. 



E. Icel. 61, 68 - N. Icel. 217. 254. 



Pi}?. 10. 



Caloneis 



fasciata 

 ([..ai'er.st. C.\. 

 t acuta n. f posed that large quantilies of nitrogenous noiirishment mav 



(X 1200;. have been present. 



In all 4 samples the Diatoms were found among mosses. 

 None of them originale from piaces in which it niay be sup- 



— — var. lenticularis Ostr. 



Ostrup 1901, p. 261. lig. 29. Navicula fontinalis Hove Petersen 1915. 



p. 286, lig. 4. 



K. Icel. L. 8, L. 129 - N. W. Icel. L. 268 - S. Icel. 336. L. 364. 



In Denmark I have found this form of the alga to be a pronounced 

 aerial alga. more especially on cultivatcd soil. The Icelandic samples are 

 derived parlly from a rocky wall basalt;, partly from soil, inter alia 

 from the vicinity of a hot spring. For No. 268 see under Achnanthes 

 pygmæa fp. 380). 



