6 ARKIV FÖR BOTANIK. BAND 17. NIO 13. 



the basal portion. In certain instances setae were found 

 which had broken off at the place where the basal nodule | 

 is applied to the cell wall. This breaking off of the spines j 

 is not found in L. suhsalsa Lemm., L. longiseta (Lemm.) 

 Printz and L. ciiriformis (Snow) G. M. Smith; species that 

 have been referred to the genus Chodatella of Lemmermann. 

 If it can be shown that the setae of all Lagerheimia species 

 with swollen bases apposed to the cell wall also break off 

 readily there may be a justification for a separation into 

 the two genera Lagerheimia and Chodatella, but for the pre- 

 sent the two are united in a single genus. 



Considerable varation was also noted in the occurrence 

 of a pyrenoid. In a majority of individuals the pyrenoid 

 was lacking but in some it was very well defined. 



Dactylococcopsis irregularis sp. nov. Figs. 26—28. 



Cells solitary, free floating, without a gelatinous enve- 

 lope. Cells very narrowly acicular, with ends drawn out into 

 fine points, twisted to form lax spirals with two or three 

 turns. Cell contents homogeneous, pale grey-green in color. 



Distance between apices 27—45 [j., diameter of cells 



1—1,5 (X. 



The twisting, coupled with the lack of a gelatinous en- 

 velope, suggests that the alga may be an Ankistrodesmus 

 rather than a Dactylococcopsis species but the pale homo- 

 geneous grey-green color of the cell contents shows that it 

 is not a member of the Chlorophyceae. 



In general shape of the cells the species is closely rela- 

 ted to D. acicularis Lemm. but it differs in the lack of a 

 gelatinous envelope, the solitary habit, and the twisting of 

 the cells. 



