86 SPECIES OF DESMIDS. 



g. End with numerous pearly teeth or beads . . coronulatum, 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 (i). 



i. 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 (/). 



/. " 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. "j-izjx, 



?mnutum, 52 

 k. " " " " cell, large; diam. ends soyU, 



Woodii* 

 I. Diameter y^^ in. (25/i); about 20 times longer than wide, 



repandum, 50 

 /. Diameter yjVs" ^o t"sVb ''^- (13-1^/^); 15-20 times longer than wide, 



dilatatum, 50 

 /. Diameter ■j^Vb' '^^ fitW 'n. (io-i2/<); 18-20 times longer than wide, 



undulatum, 51 

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



Georgicum* 



15. TRIPLOCERAS. FIG. 15. 

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



I. Tooth-like prominences oblong verticillatu77i, 53 



5. " acute . . . ... . . gracile, 53 



16. CALOCYLINDRUS. FIG. l6. 



§ Chlorophyll homogeneous (i). 



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



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



