188 WISCONSIN PHYTOPLANKTON 



PLATE 72. 



All figures x 500. 



Page 



Figs. 1-4. Staurastrum 'bracMatum Ealf s 82 



Figs. 5-7. Staurastrum pseudopelagicum W. & G. S. West 83 



Figs. 8-11. Staurastrum pseudopelagicum var. tumidum var. nov 84 



Figs. 12-14. Staurastrum cingulum (W. & G. S. West) G. M. Smith 84 



Figs. 15-22. Staurastrum paradoxum Meyen 85 



