KEY TO THE SPECIES OF THE DESMIDS. 



I. GONATOZYGON. 



1. Cells swollen at base, with 6 longitudinal lines of short setae, 



sex-spiniferum** 



2. Cells not swollen at base (a). 



a. With hair-like spines clothing the surface .... pilosiun, 22 

 a. Without hair-like spines; surface minutely roughened, asperum, 22 



2. GENICULARIA.* FIG. 2. 



i. Cells 3^ to 6 times longer than broad; granules in spirals, 



Americana* 

 i. Cells 10-12 times longer than broad; granules scattered, spirotania* 



3. HYALOTHECA. FIG. 3. 



i. Cells slightly constricted, length % the width, sides not notched, 



dissiliens, 2 2 



1. " " " " " sides arched, cen- 



trally lunched hians** 



2. Cells slightly concave, length twice the width . . undulata, 23 



3. Cells not constricted, margins straight; sheath wide, mucosa, 23 

 3. " sheath absent, diibia, 24 



4. BAMBUSINA. FIG. 4. 



1. Cells hub-shaped, somewhat longer than broad . Brebissonii, 24 



2. Cells hub-shaped, nearly twice as long as broad . gracilescens** 



3. Cells subcylindrical, 4 times longer than broad . delicatissiuia, 25 



*Journ. R. Micr. Soc., Dec., 1885. 

 **F. W. Alga, p. 21. 



