NOTE ON THE TEXT. 



For reasons mentioned in the preceding volume (on p. 274) 

 several species of Cosmarium which were there figured are 

 described in the present volume. 



EXPLANATION OF THE LETTERING. 



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



b, I)'. Vertical view. 



c. Side view. 



d. Basal view of semicell. 



