88 SPECIES OF DESMIDS. 



e . Margins crenate, undulate, dentate or granulate (r). 

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



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



Smolandicum, 69 



f. 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, 



aculeatuni) 66 

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



trachypleurum, 73 



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

 h. Margins smooth (//). 



i. Verrucae or granules in patterns, or more or less restricted (tin), 

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



surface (w). 

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



j, " " semi-cell spherical, uioniliforme, 60 



/ " " semi-cell elliptical or oval . cordanum* oblongnm\ 



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



j, " semi-cell pyramidal parvulum* 59 



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

 k. Cells not joined into families (/). 



/. Ends rounded; semi-cells oblong citcitnris, 58 



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



Witrockii\ 

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



yyt^ (22-28/4) notabile, 66 



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



irrro (5- 8 5/^) pyramidatum, 69 



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



to -gJ-y (25-43;^) pseudopyramidatum^ 69 



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



concave, .granatum, 60 



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



side view circular, end view elliptical; diameter 32-38^, 



scene desmus, 59 

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



side view ovoid; diameter 75-85^ circulare** 



* Journ. R. Micr. Soc., Dec., 1885. f Journ. R. Micr. Soc., Feb., 1886. 

 ** F. W. Algae, p. 27 el seq. 



