EXPLANATIONS AND REFERENCES, 

 PLATE LXXXIII. 



Figures magnified 250 diameters. 



PAGE. 







Figs. 1, 2. OEDOGONIUM RIVULARE, . . 92 



Fig. 3-G. OEDOGONIUM STAGNALE, 88 



Figs. 7, 8. OEDOGONIUM CAPILLARE, . 87 



Fig. 9. OEDOGONIUM STAGNALE, Var., . . 92 



