FRESH-WATER DIATOMS FROM ICELAND 15 



Stauroneis obtusa Lgst. Cl. Syn. I, 149. Lgst. Spb., Tab. I, fig. 11. 

 Ketilsstaôir (S.W.:, H. Js. 

 Area: J. M., Spb., Fr. J. 



Stauroneis parvula Grim. Var. producta Grun. Cl. Syn. I, 149. V. H. 

 Syn., Tab. IV, fig. 12. 



31 samples (S. 2, S.W. 14. NAV. 3, N. 3, E. 9). 

 Area: Eur., Grl. 



Var. capitata var. now, Tab. nost. I, fig. 16. 



Long: 46 //, lat; 10 //. 



Valva elliptica, apicibus capilatis, diaphragmate distincto instruc- 

 tis. Raphe area hyalina distincta cincta. Stauro satis angusto. Slriis 

 subtilissimis, radian tibus. 



Reykjavik S.W. . Stp. 



Tbis form is nearest to Staur. parv. prod, forma subcapitata in my 

 D. D. P. 47, Tab. II, lig. 34, but to me it seems nevertheless differing suf- 

 ficiently for placing it as a special variety. 



Stauroneis perexilis sp. now, Tab. nost. I, fig. 17. 



Long: 20 //, lat: 4,5 //. 



Valva lanceolata, apicibus diaphragmate instructis. Raphe area 

 hyalina angusta, mediam partem valvæ versus patescenti, cincta. 

 Structuram ullam valvæ perspicere non potui. 



Reykjavik S.W. , H. Js. 



i: Stauroneis Phonicenteron Ehr. Cl. Svn. 1, 148. V. H. Tit., Tab. I, 

 fig. 50. 



65 samples (S. 6, S.W. 20. X.W. 3. X. 10, E. 25, s. 1. 1). Hot spring. 1. 

 Area: Ubiquist, Grl. 



Var. amphilepta Ehr. Cl. Syn. I, 149. Hérib. Auw, Tab. Ill, fig. 18. 

 30 samples (S. 6, S.W. 7, X.W. 1, X. 2, E. 14). 

 Area: Eur., Afr., Aust., Grl., B. E. 



Stauroneis Smithi Grun. Cl. Syn. I, 150. V. H. Tit., Tab. 1, fig. 58. 

 Skeiôarârsandur (S.) St., Vallanes E., two samples , H. Js. 

 Area: Eur., As., Am. 



S. Stefanssoni sp. now, Tab. nost. II, fig. 18. 



Long: 46 //, lat: 8 /<, str. 20 in 10 fi. 



Valva lanceolata, margine undulato, in medio lender inciso. 

 Âpicibus apiculatis, diaphragmate distinclo instructis. Raphe area 

 hyalina angusta cincta. Stauro bifisso. Striis radiantibus. 



Skeioarârsandur S. St. 



This pretty and characteristic form probably belongs to the group 

 of St. Smithi. It has the median constriction in common with St. Smithi 

 var. incisa: Pant, in Pant. Bel. S.. 27. Tab. II. fig. 45, but differs otherwise 

 to such extent, that I do not think it can be classed with this form; nor 

 can it be identical with Schizostauron Karsteni O. M. in Ch. Xyassa, 88, 

 Tab. II. figs. 17—18. It undoubtedly deserves a place as a distinct species. 



