2 08 



CLASSIFICATION OF DESMIDIACE/E. 



than tliey are broad, and that they are neither constricted nor 

 furnished with lateral teeth or projections ; whilst in the other set 

 (of which Didymoprium, Fig. 115, is an example) the length and 



Fig. 115. 



Binary subdivision and Conjugation of Didymoprium Gre- 

 villii : — a, portion of filament, surrounded by gelatinous enve- 

 lope ; b, dividing joint ; c, single joint viewed transversely ; v, 

 two cells in conjugation ; e, formation of sporangium. 



breadth of each joint are nearly equal, and the joints are more or 

 less constricted, or have lateral teeth or projecting angles, or are 

 otherwise figured ; and it is for the most part upon the variations 

 in these last particulars, that the generic characters are based. 

 The solitary group presents a similar basis for primary division 



