PLATE IX. 



Figures magnified 250 diameters. 



PAOE. 

 Fig. 1. CLOSTERIUM ROSTRATCM, . . . . .49 



" 2. " first stage of the copulation of two cells, 



" 3. the developed zygospore and empty 



semi-cells, . . . .49 



<! 4. CLOSTERIUM DIAN.E, zygospore and remains of empty cells, 47 



u 5. CLOSTERIUM ATTENUATUM, . . . . .44 



Figs. 6, 7. CLOSTERIUM SETACEUM. ..... 60 



Fig. 8. CLOSTERIUM KUETZINGII, . . . . .50 



Figs. 9-11. CLOSTERIUM SETACEUM, three zygospores, before the emptied 



cells have been shed, . . .50 



" 12, 13. CLOSTERIUM DIDYMOTICUM, two cells, . . .40 



Fig. 14. CLOSTERIUM LANCEOLATUM, (see also Plate VI, figs. 18-20), . 40 



" 15. CLOSTERIUM LISEATUM; zygospore and em ptied semi-cells, 46 



" 16. CLOSTEHIUM PARVULUM, zygospore, . . . .47 



" 17. CLOSTERIUM ACEROSUM, chlorophyl broken up and formed into 



small oval cells, . . .43 



