(274) 



NOTE ON THE PLATES. 



Owing- to exigencies of space it was found that the genus 

 Cosmarium would have to be completed in the next volume 

 (vol. iv). In consequence of this, the descriptions of the 

 following* species, figured in the present volume,, will be found 

 in vol. iv : 



C. Grantii . . .PL XCL fio-. 11. . 



C. Gay, mum . PL XCIII, figs. 6-8. 



C. latifrons . .PI. XCIY, fig-. 6. 



C. eylindricum . . PI. XCIV, fig. 7. 



C. subcylindricum . PI. XCIY, fig. 8. 



C. promontorium . PI. XCIY, fig. 9. 



C. lepidum . . .PL XCIY, fig. 10. 



The zygospore of (7. punctulatum, described on p. 207, is 

 figured (fig. 22) on PL CII in the next volume. 



EXPLANATION OF THE LETTERING. 



, a ', a" . Front view of cell or semicell. 

 I), //. Yertical view. 



c. Side view. 



d. Basal view of semicell. 



