EXPLANATIONS AND REFERENCES, 



PLATE CXXXVIIT. 



Figures magnified 250 diametei's. 



PAGE. 

 Fig. 1-4. SPIROGYRA SETIFORMIS, ...... '219 



Figs. 5. 6 SPIROGYRA MAXIMA, Var. inequalis, . . . 218 



" 7, 8. SPIROGYRA JUGALIS, ...... 219 



