PLATE XCIII. 



FIGS. PAGE 



1. Cosmarium ovale Ralfs, showing parietal dis- 

 position of chloroplasts. x 520. [Consult 

 PL XCII, fig. 1, and PI. XCIV, fig. 1.] . 267 



2. C. Debaryi Arch. The upper semicell shows 

 the numerous small lobes of the chloroplasts 

 flattened against the wall of the cell. The 

 lower semicell represents an optical section 

 through the chloroplasts showing the parietal 

 disposition and the large central vacuole (c.v.). 

 p, pyrenoids. x 600 (after Liitkem tiller). 

 [Consult PI. LXX, figs. 14-16.] . . 61 



3. C. quadrimamillatum West & Gr. S. West, a, 



a', and 6, x 520; a", x 400 . . 125 



4. G. quadratulum (Gray) De Toni. Three indi- 

 viduals, x 1000. [Consult PI. LXXir, fig. 

 33.] . . . . .121 



5. C. quadridentatum West & G-. S. West, x 520 133 

 6-8. C. G-ayanum De Toni var. eboracense West & 

 Gr.-S. West, x 400. The description of C. 

 Gayanum is in the next volume. 



