FRESH WATER ALG/E. 



PLATE IX. 



m 



n 





i«J. 







V'- 





r *>* .» • • • *\«.» ft • ,' 



2S0 \ 







If ~W- 



^FTER NATJRE BY DR " C .■.' 3 O D 



TS(NCL*iR 6S0N ("HiLADtLPHlA 



Fig. 1. SIROSIPHON SCYTENEMATOIDES. 1 



Fig. 2. SIROSIPHON UIGNICOLA. 

 Fij 4-. STIGONEMA RAVENELLII. 



Fig. 3. S. ARGILLACEA. 



