HOW TO KNOW THE FRESH-WATER ALGAE 



347a Cell within a variously shaped envelope (lorica), with a flagel- 

 lum opening 348 



347b Cell without such an envelope. 



352 



348a Envelope cone-shaped, narrowed posteriorly to a blunt or sharp 

 point 349 



348b Envelope flask-shaped, globose or pyramidal 



350 



349a Envelope with smooth or slightly wavy margins; without trans- 

 verse growth rings. See Fig. 243 D1NOBRYON 



349b Envelope with marginal, bristle-like projections caused by trans- 

 verse growth rings. Fig. 244 HYALOBRYON 



Fig. 244. Hyalobryon mucicola (Lemm.) Pascher. 



This species is solitary and the envelope has margins 

 which have bristles which represent the remains of the 

 envelopes of previous generations of cells. Whereas 

 Dinobryon (Fig. 243) is freely swimming, this genus is 

 solitary or colonial as an epiphyte on filamentous algae. 



Figure 244 



350a (348) Cells free-swimming; envelope globose, with long spines; 

 flagellum collar narrow. Fig. 245 CHRYSOSTRELLA 



Fig. 245. Chrysostiella paradoxa Chod. 



This is the only species reported from this 

 country, occurring either in open water plank- 

 ton or intermingled among mixtures of algae 

 near shore. The test or envelope bears a 

 few long needle-like setae which are often 

 forked at the tips. The round or oval cells 

 with a short collar around the flagellum aper- 

 ture make this organism easy of identification. 



Figure 245 



350b Cells attached, usually not globose; without spines 351 



146 



