70 



ERNST ØSTRUP 



bacillaris 



bodonensis 



Clevei 



fasciata 



ladogensis 



obtusa 



Silicula genuina 



— alpina 



— biconstricta . . 



— inflata 



— subventricosa . 



— ventricosa .... 



Catnpylodiscus 



hibernicus noricus . . . 



Ceratoneis 



Arcus 



Cocconeis 



flexella 



— intermedia. . . . 

 minuta 



— alpestris 



Placentula 



Cyclotella 



antiqua 



comta 



Kützingiana , 



Meneghiniana 



Cymatopleura 



elliptica 



Solea 



Cymbella 



æqualis 



affinis 



amphicepbala 



angustata 



aspera 



— dubravic 



Ceratii 



Cistula 



Universal distribution 



Eur. Af. 



Im. 



X I X I X 



Uri. 



Spb. 



F/..I 



Distribution in the 



different parts 



of Iceland 



S. 



S.WJlV.W. 



I 



