PLATE LXXIII. 



FIGS. PAGE 



1-3. Cosmarium difficile Liitkem. 1, x 1000 (after 



Lutkemiiller) ; 2 and 3, x 520 . . 96 



4-5. C. difficile var. sublseve Liitkem. 4, x 1000 

 (after Liitkemiiller) ; 5, x 520. The delicate 

 scrobiculations are not shown on fig. 5 . 97 



6-7. C. Clepsydra Nordst. 6, x 570 (after Norcl- 



stedtj; 7, x 520 . . . 98 



8-19. C. Iseve Eabenh. 8 and 9, x 520; 10 and 11, 

 outlines, x 520 ; 12, x 570 (after Nord- 

 stedt); 13-16, x 520; 14 and 16, outlines; 

 17, monstrosity, x 520; 18 and 19, zygo- 

 spores, x 520 . . . .99 



20. C. lieve var. octangulare (Wille) W. & G-. S. 

 West. 20a, x 400 (after Wille) ; 20a f , x 

 520 . . . . . 101 



21. C. Ixve var. cymatium W. & G. S. West. x 520 103 

 22-25. C. Idsve var. septentrionale Wille. 22, x 400 

 (after Wille) ; 23, x 520; 24 and 25, showing 

 an undulation of the superior lateral margins 

 of the semicells, x 520 . . .102 



26. C. monochondrum Nordst. x 570 (after 



Nordstedt) . . . .103 



27-28. C. Thwaitesii Raits. 27, x 400 (after Rails) ; 



28, x 400 ... 104 



29-30. C. Thwaitesii var. penioides Klebs. 29, x 400 



(after Klebs) ; 30, x 400 . .105 



31-33. C. Cucurbita "Breb. x 500 . 106 



34-36. C. Cucurbita var. attenuatum G. S. West. 34, 

 x 540 ? (after Schmidle) ; 35, x 520 ; 36, 

 x 500. 108 



