180 



WISCONSIN PHYTOPLANKTON 



PLATE 68. 

 All figures x 600. 



Page 



Figs. 1-3. Staurastrum pseudopachyrhynohum Wolle 69 



Fig. 4. Staurastrum alternans De Breb 70 



Figs. 5-7. Staurastrttm denticulutum (Nag.) Arch 70 



Figs. S-10. Staurastrum avicula De Breb 71 



Figs. 11-13. Staurastrum lunatum var. planctonicum W. & G. S. West 71 



Figs. 14-17. Staurastnun aristiferum var. indentatum var. nov 72 



Figs. 18-24. Staurastrum dejectum De Breb 73 



Figs. 25-26. Staurastrum dejectum var. inflatum W. West 74 



Figs. 27-34. Staurastrum cuspidatum De Breb 74 



