EXPLANATIONS AND REFERENCES, 

 PLATE CXXXVI. 



Figures magnified 250 diameters 



PAGE. 

 Fig. 1-3. SPIROGYRA FLUVIATILIS, . . . ... 216 



u 4-7. SPIROGYRA RIVULARIS, ..... 220 



Figs. 8, 9. SPIROGYRA NEGLECTA, . . . . . .216 



" 10, 11. SPIROGYRA ORTHOSPIRA, ..... 218 



