PLATE VII. 



Figures magnified 250 diameters. 



Page. 

 Fig. 1. Closterium obtdsitm, ... 39 



" 2. CliOSTERTUM JUNCIDDM, . . 39 



" 3. " " two cells with developed zygospore, . 39 



Figs. 4,5. Closterium gkacile, ..... 40 



Fig. 6. Closterium macilentdm, . . . 40 



" 7. CiiOSTERiDM acerosdm, Zygospore and empty cells, . 42 



" 8. Closterium striolatdm, . . . .44 



Figs. 9, 10. ClOSTSERIUM DECUSSATDM, . . . 41 



Fig. 11. Closterium acerosum, vegetative cell, . . 42 



" 12. Closterium >"AsrTUM, . . 43 



Figs. 13, 14. Closterium strigosum, ... . . 44 

 Fig. 15. Closterium turgidum, ... .43 



" 16. Closterium lineatum, two cells, (see Plate IX, fig. 15), . 45 



Figs. 17, 18. Closterium cucumis, .... 42 



Fig. 19. Closterium costatum, . . ... 45 



' 20. Closterium striolatdm, (compare fig. 8, and Plate VI, 



figs. 5-8), . . , 44 



Figs. 21-23. Closterium ahqustatum, and variety decussatum, . 41 



