PLATE XLVIIL 



FIGS. PAGE 



1-6. Micrasterias rotata (Grrev.) Ralfs. 1, x 500 ; 2 

 and 3, polar lobes of two individuals, x 220 ; 

 4, vertical view, x 200 (after Archer) ; 5, 

 side view, x 200 (after Archer) ; 6, zygo- 

 spore, x 400 (after Lundell) . . 102 



