94 SPECIES OF DESMIDS. 



XX. Sides granulate, concave near the ends; semi-cell twice longer 



than wide . . protr actum, 83 



XX. Sides granulate, ends concave; semi-cell twice wider than long, 



biretum var. Floridense.^ 

 XX. Sides crenate-undulate, converging; cytioderm verrucose, 



Quasillus, 84 

 XX. " rounded, acutely toothed, ends usually nude; cell as long 



as wide . . Everettense, 85 



XX. " straight, diverging, verrucose; angles rounded, biretum, 86 



yy. Cytioderm granulate; cell widest at base, sides converging, 



sportella, 83 

 yy. " " cell narrowed at base, sides straight, diverging, 



protuberans, 84 



yy. Cytioderm verrucose; end more or less protruding and scolloped 



(4-crenate) ... . . . . . ccslatum, 86 



yy. Cytioderm verrucose; end more or less protruding, not scolloped, 



ornatu7n, 82; protractum, 82 



yy. " " end not protruding; semi-cell twice as long 



as wide, oblong-quadrangular, angles rounded, Broomei, 86 



zz. Cytioderm finely granulate or punctate; semi-cells triangular, 



angles rounded, margins smooth . ... Turpinii, 158 



zz. Cytioderm verrucose; semi-cell subreniform, 3 times as wide as 



long . . ... commisurale, 83 



zz. " " semi-cell pyramidal, angles rounded, long, 



tumidum, 75 



zz. " " semi-cell reniform, angles denticulate, a 



central inflation granulate . ... subcruciforme.* 



18. Tetmemorus. Fig. 18. 



§ Cytioderm smooth or very indistinctly punctate (c). 

 § Cytioderm punctate {a). 



a. Cell 3 times as long as wide, irregularly granular; base slightly 

 plicate. . gtganieus, '92 



a. Cell more than 3 times as long as wide (b). 



b. Front and lateral views fusiform; end with colorless, lip-like pro- 



jection . ... . . ... granulatus, 91 



b. Front view cylindrical, not tapering; side view fusiform, tapering; 

 end rounded . . . Brebissonii, 91 



* F. — w. Algae, p. 27 et seq. 



