FRESH-WATER DIATOMS FROM ICELAND 



71 



Cistula arctica 



— Caldogast. . . . 



— maculata 



cuspidata 



cymbiformis 



Ehrcnbergi 



delecta . . . 



gracilis 



helvetica 



heteropleura min. . . . 



incerta navic 



lanceolata 



— cornuta . . . 



— ventricosa . 



lapponica 



microcephala , 



naviculiforniis 



parva 



prostrata 



sinnata 



stauroneiformis 



turgida 



ventricosa 



Denticula 



elegans 



snbtilis 



tennis 



Diatoma 



hiemale 



elongatnm 



— minus 

 tenue 



vulgare 



Diatomella 

 Balfouriana 



Diploneis 



Boldtiana 



robusta . . . 



elliptica 



ovalis 



