PLATE XLVI. 



Figures magnified 500 diameters ; the Mlcrasterias 375 diameters. 



Page. 



Fig. 1. MiCRASTERIAS Alata, . . . . 125 



" 2. MiCRASTEEIAS MAMILLATA, . . . 125 



" 3. MiCRASTEEIAS DENTICULATA, zygospore, . 120 



" 4. Staurastkum arotiscon, Var., . . . 163 



'■ 5. CosMARiUM CONSPEESUM, Var. retusum, front view, . . 82 



" 6. CosMAEitnvi BrRETUM, Var. Floridense, front view, . 93 



Figs. 7, 8. Staueastedm cosmaetoides, front and vertical views, 139 



" 9, 10. Statjeasteum brevispina, Var. inerme, . . 134 



" 11, 12. Staurastrum cornu*dm, front and vertical views, . . 158 



