PLATE X. 



Figures magnified 500 diameters except Closterlum, only 250 diameters. 



I'.UiK. 



Figs. 1, 2. CLOSTERIUM ACEROSUM, forma striolatmn with single and twin 



zygospores, . . . .42 



Fig. 3. CLOSTERIUM LINEATUM, Var. costatum, with twin zygospores, 45 



Figs. 4, 5. ARTHRODESMUS NOTOCHONDRUS, in front and vertical views, . 105 



Fig. 6. A^THRODESMUS INCRASSATUS, Var. cycladatus, . . 105 



Figs. 7, 8. COSMARIUM OCULIFERUM, front and lateral views, . . 76 



" 9-11. PENIUM CRUCIFERUM, in different stages of division, . 38 



" 12, 13. ARTHRODESMUS PACHYCERUS, front and lateral views, . . 105 



14,15. A RTHRODESMUS TRIANOULARIS, front and vertical views, . 105 



Fig. 16. DOCIDIUM GEORGICUM, . . . . . .55 



" 17. PENIUM SPIROSTRIOLATUM, var., .... 35 



"19. " " 35 



' 18. DOCIDIUM VERTICILLATUM, ..... 58 

 Figs. 20, 21. DOCIDIUM RECTUM, ... . 52 



