182 WISCONSIN PHYTOPLANKTON 



PLATE 69. 

 All figures x 500. 



Page 



Figs. 1-3. Staurastrum cuspidatum var. canadense G. M. Smith 75 



Figs. 4-9. Staurastrum curvatum W. West 73 



Figs. 10-15. Staurastrum curvatum var. elongatum var. nov 73 



Figs. 16-21. Staurastrum megacanthum Lund 75 



Figs. 22-24. Staurastrum megacanthum var. scoticum W. & G. S. "West 76 



