Plate YIII; Figures 57 to 60; All Magnified 500 Diam- 

 eters. 



Fig. 57. Pediastrum pertustim var. clathra- 



tinn A. Br page 38 



Figs. 58, 59. Pediastrum Boryamtm (Turp.) 



Meneg. var. granulatum Kiitz. . " " 



Fig. 60. Spirogyra crassa Kiitz. ... "67 



