WISCONSIN PHYTOPLANKTON 205 



PLATE 20. 



Paga 



Figs. 1-2. G-loeocystopsis Umneticus (x 1000) , 103 



Figs. 3-6. Planktosphaeria gelatinosa (x 1000) 103 



Figs. 7-10. Asterococcus Umneticus (Fig. 7, x 500; figs. 8-10, x 1000) . 104 



Figs. 11-12. Dictyosphaerium Ehrenbergianum (x 1000) 105 



Fig. 13. Dictyosphaerium pulcUellum (x 1000) 105 



