Plate 51 



Figs. 1, 2. Echinosphaerella limnetica G. M. Smith, x 750 (after 

 Smith) 



Figs. 3, 4. Dictyosphaerium Ehrenhergianum Naegeh: 3, x 312; 4, 



x375 



Figs. 5-7. Dictyosphaerium pulchellum Wood: 5 and 6, x 500; 7, 

 details of cells and attaching strands, x 500 



Fig. 8. Treubaria setigerum (Archer) G. M. Smith, x 750 (re- 



drawn from Smith 



Fig. 9. Oocystis crassa Wittrock, x 1000 ( redrawn from Smith ) 



Fig. 10. Oocystis Borgei Snow, x 750 



Fig. 11. Oocystis elliptica W. West, x 600 



Fig. 12. Oocystis Eremosphaeria G. M. Smith, x 590 



Fig. 13. Oocystis gloeocystiformis Borge, x 350 



Fig. 14. Oocystis gigas Archer, x 500 



Fig. 15. Oocystis pusilla Hansgirg, x 1000 ( after Smith ) 



[762] 



