86 SPECIES OF DESMIDS. 



g. End with numerous pearly teeth or beads . . coromilatum, 49 

 g. End with prominent teeth, about 3 in view . . tridentulnm, 52 

 h. End with 3-5 minute tubercles; semi-cell with 4 or more undu- 

 lations Floridense, 159 



h. End with toothed angles (/"). t 



2. Semi-cell with 4 prominent nodes; 8 to 10 times longer than wide, 



nodosum, 50 

 /. " " 4 constrictions; 10-12 times longer than wide, 



breve, 51 

 /. " " 8 constrictions; 20-24 times longer than wide, 



sinuosum, 51 



j. Semi-cell with i basal inflation (k). 

 j. " undulate to near the end (/). 

 j. with 4 larger and smaller undulations; cells 12 times as 



long as wide (m). 



j. Semi-cells not or slightly undulate; densely granulate, breve, 158 

 k. Cytioderm densely, irregularly punctate .... clavatum, 48 

 k. " smooth; ends truncately rounded, margins often wavy, 



Baculum, 49; rectum* 

 k. " ends round; cell minute; diam. 7-12^, 



minutum, 52 

 k. " " " " cell, large; diam. ends 50^, 



Woodti* 

 1. Diameter -j-^ in. (25/1); about 20 times longer than wide, 



repandum, 50 



/. Diameter ^-^ to -j-gVir ^ n - ( I 3- 1 ^/^)' I 5~ 20 times longer than wide, 



dilatatum, 50 



/. Diameter ^^ to -^^ in. (io-i2yu); 18-20 times longer than wide, 



undulatum, 5 1 

 m. Surface punctate; suture none; ends roundly truncate, 



Georgiciun* 



15. TRIPLOCERAS. FIG. 15. 

 (Mr. Wolle unites this with Docidium, 14.) 



i. Tooth-like prominences oblong verticillatum, 53 



5. acute gracile, 53 



l6. CALOCYLINDRUS. FIG. 1 6. 



Chlorophyll homogeneous (i). 



" divided or scattered in each semi-cell (2). 



*F.-w. Algae, p. 25 et seq. 



