88 SPECIES OF DESMIDS. 



^. Margins crenate, undulate, dentate or granulate (f). 

 e. Margins smooth; basal angles not toothed (w). 



e. Margins smooth; basal angles each with i, tooth or papilla, 



Smolandicum, 69 

 /. Verrucae or granules in patterns, or more or less restricted {x). 



f. " " " not in patterns; more or less covering the 



surface (cc). 



g. Spines on the whole surface; cell suborbicular; sinus elliptical, 



aculeatum, 66 

 g. Spines marginal, conical; centre with 7 granules, and punctate, 



trachypleurum^ 73 

 h. Margins crenate, undulate, or dentate {jj). 

 h. Margins smooth (//). 



/. Verrucse or granules in patterns, or more or less restricted {nii). 

 i. " " " not in patterns, more or less covering the 



surface (vv). 

 j. End rounded; semi-cell oblong, sides almost parallel, De Baryi, 58 

 j. " " semi-cell spherical, . . moniliforme, 60 



j. '■ " semi-cell elliptical or oval . corda?ium* oblongum\ 



j. End truncate; semi-ceil quadrate, sides almost parallel, anceps, 59 

 / " " semi-cell pyramidal . parvulum, 59 



k. Cell joined by pellucid bands into families Quimbyii, 61 



k. Cells not joined into f:Lmilies (/). 



/. Ends rounded; semi-tells oblong . . cucumis, 58 



/. " " semi-cells oval; diameter y^ij^ in. (23//), 



Witrockii\ 

 I. Ends truncate; semi-cells pyramidal, sides convex; diameter -^^ to 



y^ij^ (22-28/*) . . . notabile, 66 



/. Ends truncate; semi-cells pyramidal, sides convex; diameter ^-^ to 



-g-J-Q (So-85/O ■ • ■ • py7'amidatmn, 69 



/. Ends truncate; semi-cells pyramidal, sides convex ; diameter y^ij^' 



to -j-J^ (25-43yu) . . pseudopyramidatum, 69 



/. Ends truncate; semi-cells pyramidal; sides straight or slightly 



concave, . . . . .... . .granaium, 60 



m. Cell conspicuously broader than long; semi-cells subsemicircular; 



side view circular, end view elliptical; diameter 32-38/*, 



scenedesmus, 59 

 m. Cell conspicuously broader than long; semi-cells subsemicircular; 



side view ovoid; diameter 75-85/* . . circulare.** 



* Journ. R. Micr. Soc, Dec, 1885. t Journ. R. Micr. Soc, Feb., i886. 

 ** F. W. Algse, p. 27 et seq. 



