HOW TO KNOW THE FRESH-WATER ALGAE 



352b Cells either not motile, or moving by pseudopodia (amoeboid 

 fashion), or by 2 flagella; wall without scales and needles. . . .353 



353a Cells amoeboid; protoplast very pale yellow-green or yellow- 

 brown 354 



353b Cells swimming by 2 flagella, or sedentary; protoplast deeply 

 pigmented, usually a golden brown or blue 355 



354a Pseudopodia long and needle-like. Fig. 249 RHIZOCHRYSIS 



Fig. 249. Rhizochrysis limnetica 

 G. M. Smith, a, single cell; b, 

 / cells in temporary colonial ar- 



\\// \// / rangement. 



• X. "^r^ This is the only species of the 



~^\^v£tv . J^Cfer >)--. genus reported in the United 



--^tf^sS if ^C^&i States. The amoeboid member of 



-^/^-rASS^N^ \ the Chrysophyta has long, slen- 



b \ der needle-like pseudopodia. Cells 



are ordinarily solitary but may oc- 



Figure 249 cur - m ] oosef temporarily united 



colonies. 



354b Pseudopodia short, tapering from the base to a fine point. Fig. 

 250 CHRYSAMOEBA 



Fig. 250. Chrysamoeba radians 

 Klebs. a, single cell; b, tem- 

 porarily adjoined cells. 



This species, the only one re- 

 ported, occurs more commonly 

 than Rhizochrysis (Fig. 249). Usu- 

 ally the cells occur in an amoe- 

 boid condition, bearing short, 

 sharply pointed pseudopodia, but 

 may change to a condition in 

 which a single flagellum is present 

 as a locomotory organ. 



Figure 250 



355a (353) Cells attached 356 



355b Cells floating free, or swimming 357 



148 



