HOW TO KNOW THE FRESH-WATER ALGAE 



444a Cells elongate; pointed at the ends. Fig. 323 



DACTYLOCOCCOPS1S 



Fig. 323. a, Dactylococcopsis acicularis 

 Lemm.; b, D. fascicularis Lemm. 



These are fusiform shaped cells ar- 

 ranged with their long axes mostly- 

 parallel with that of the fusiform-shaped 

 colonial envelope. Two species are 

 known from this country, occurring in 

 the plankton. 



Figure 323 



444b Cells not pointed at the ends 445 



445a Cells heart-shaped, at the ends of radiating strands of mucilage; 

 colonies globular. See Fig. 314 GOMPHOSPHAERIA 



445b Cells not at the ends of radiating strands 446 



446a Cells radiately disposed. Fig. 324 MARSSONIELLA 



Fig. 324. Maissoniella elegans Lemm. 



This species (the only one reported) has 

 pear-shaped cells more or less definitely 

 arranged about a common center with 

 scarcely any evidence of a colonial muci- 

 lage. It is to be looked for in the plank- 

 ton of open water. 



Figure 324 



446b Cells not radiately arranged 447 



184 



