FRESH WATER ALG/E. 



PLATE XVII. 



r 



I 



NCtAlH & SON. PMH.AQILPHIA. 



AFTER NATURE B* D» MCWOOtS 



F.g. 1. SCHIZOMERIS LEIBLEINII 

 •• 2. OEOOaONIUM HUNTII 

 " 3. O, MULTISPORA 



Fig. 4. SPIROGYRA 0U8IA 

 " 5. S. RIVULAIS. 



