102 SPECIES OF DESMIDS. 



23. STAURASTRUM. FIG. 23. FOUR FORMS. 



% With numerous processes, their ends more or less divided (§ §) 



T[ Without processes, the angles in front view produced or not (§) 



§ Cytioderm smooth or finely punctate (i). 



§ Cytioderm verrucose or granulate (2). 



§ Cytioderm hirsute, spinulose or thorny (3). 



§§ End view 2-armed, body broadly ovate; arms serrate, apices 



finely toothed Minneapoliense* 



§§ End view 3 or 4 angled (B). 



§ § End view 5 or 6-angled, apices of (6) rays rounded and spinulose, 



Kissimmense* 

 §§ " 5 angled, apices spinous (G). 



§§ End view 6-angled, apices of cylindrical processes slightly 



notched, 4 processes within the margin; end view hexagonal, 



Wolleanum.* 

 §§ " " apices of (5-6) rays trifid, distended, 



distentum, 149 

 § § End view 8-angled; rays a whorl of 8 below, 4 above, 



tetroctocerum, 151 

 §§ End view circular, rays a whorl of 9 below, 6 above, artiscon, 148 

 § § " " rays marginal, very short, usually 9, ends notched, 



Eloiseanum, 149 

 r. Angles of semi-cell in front view, not produced; rounded and 



smooth (a). 

 I. " " " " " mucronate, spi- 



ous or notched (c). 



1. Angles of semi-cell in front view produced more or less {K). 



2. Angles of semi-cell in front view more or less produced (/). 



2. " '■ " " " not produced {gg). 



3. Angles of semi-cell in front view more or less produced {00). 



3. " " " " " not produced {yy). 



a. Semi-cell oval or elliptical, ends not inflated (T). 



a. " " " ends inflated; diam. ^jVir in. (25/^), 



bacillare* 

 a. Semi cell semi-circular, smooth, sinus narrow, linear, oriicu/are, 120 

 a. Semi-cell almost circular, sides finely dentate . Cosmarioides* 



a. " " " sides smooth vesiculatum* 



a. Semi-cell triangular, sides concave trihedrale, 123 



a. Semi-cell cuneate; cell slightly longer than wide, 



pseudopachyrhynchum, 125 

 *F.-w Algae, p. 41 et seq. 



