EXPLANATIONS AND REFERENCES, 

 PLATE LXII. 



Figures magnified .501 diameters; the Micrasterias 375 diameters. 



PAGE. 

 Fig. 1. MICRASTERIAS ALATA . ... 40 



" 2. MICRASTERIAS MAMILLATA, . .39 



" 3. MICRASTERIAS DENTICULATA, zygospore, . . 39 



" 4. STAURASTRUM ARCTISCON, var., ... 45 



" 5. COSMARIDM CONSPERSUM, Var. retusum, front view, . . 31 







6. COSMARIUM BIRETUM, Var. Floridense, front view, . 34 



Figs. 7, 8. STAURASTRUM COSMARIOIDES, front and vertical views, . 42 



" 9, 10. STAURASTRUM BREVISPINA, Var. inerme, . . 42 



LI, 12. STAURASTRUM CORNUTUM front and vertical views. . . 43 



