PLATE CVIIL 



FIGS. PAGE 



1-4. Xoitthidium Smith ii Arch. 1-8, x 500; 4, x 



460 . . . . .61 



5. X. Smithii var. maim (Ralfs) W. & G-. S. West. 



x 500 .' . . .62 



6. X. Smithii var. co//>/> West. x 400 . 63 



7-18. X. antilopaeum (Breb.) Ktitz. 7, x 520; 8, x 

 400; 9, specimen showing chloroplasts, x 

 500 ; 10-17, different dispositions of the scro- 

 biculations situated in the central thickened 

 area of the semicells, x 520 ; 18, zygospore, 

 x 400 ... 63 



19. X. ctntilojife.um var. polymazuiii Xordst. x 400 



(after Xordstedt) . 67 



