EXPLANATIONS AND REFERENCES, 

 PLATE CLVIII. 



Figures magnified 500 diameters. 



PAGE. 

 Figs. 1, 2 OPHIOCYTIUM CUSPIDATUM, after specimens from Massachusetts 



and from California, . . 176 



Fig. 8-7. OPHIOCYTIUM CAPITATUM, various forms, . . . 176 



" 8-14. OPHIOCYTIUM COCHLEARE, usual appearances, . . 175 



" 15-18. OPHIOCYTIUM CIRCINATUM, from Minnesota, . . 176 



