EXPLANATIONS AND REFERENCES, 

 PLATE CLX. 



Figures magnified .500 diameters. 



PAGE. 

 Figs. 1, 2. RHAPHIDIUM CONVOLUTUM, (Selenastrum), , . 198 



" 4, 5. " " small form, 199 



" 6,7. RHAPHIDIUM POLYMORPHUM, Va.r.fulcatum, . . .187 



" 8,10, " " in different stages of growth, 198 



<f 11, 12. " ' Var. contwtum, . . .198 



Fig. 13-15. " " " " from Florida, 198 



" 16-21. " " fruiting forms, . . .198 



Figs. 22, 23. " '' Var aciculare, . . 197 



" 24, 25 " " Var. sigmoideum, . . 198 



4< 26, 27. RHAPHIDIUM BRAUNII, ..... 198 



" 28, 29. RHAPHIDIDM CONVOLUTUM, Var., . . . .199 



Fig. 30-35. DIMORPHOCOCCUS CORDATUS, coenobia in different stages of 



growth, . . 199 

 " 36-38. " " simple groups of cell in early 



stage of development, . 199 



