FRESH WATER ALG> 



PUTE IX. 



** ^t ** V*** ** 



*V .. ^* * "\ 



^#W .^^P:^ I 



' <i 1. SIROS1PMON SCYTENEMATOIOES. I 



Fig. J. SIROSIPHON L1GNICOL* 

 Fig 4-. STIGONCMA RAVENEU.il. 



