Plate XLI ; Figures 267 to 270: Magnified 500 Diameters. 



Fig. 2(^7. Staurastrum coronulatum Wolle . page 62 

 Fig. 2671;. 



End view ..... 



Fig. 268. Staurastrum arctiscon Ehrb. . 

 Fig. 268a. " " " End 



.. 



view- 



Fig. 269. Spirogyra infiata ( Vauch. ) Rab. . 

 Fig. 270. he// is (Hass.) Clev. 



67 



