132 DESMIDS OF THE UNITED STATES. 



St. Pringlei, Wblle. Plate L, figs. 25. 



Cytioderm granular ; of equal length and breadth ; con- 

 striction not deep, sinus wide ; seniicells subtriangular, sides 

 rounded, end concave with a central inflation, angles acute. 

 End view triangular, sides concave, angles acute. Membrane 

 rough with fine granules. Surrounded by a thick gelatinous 

 sheath. 



Diameter 28-33 a. 



Found by C. G. Pringle, Nebraska Notch, Vt. 



St. Do.wki.lii. Wolle. Plate LII, fig. 20. 



Small, twice as long as wide, oblong-quadrate j cytioderm 

 punctate and sulcate ; semicells quadrangular with basal 

 angles rounded, sides crenulate; superior angle- (four) pro- 

 duced into short, obtuse, diverging processes ; end view quad- 

 rangular. 



1 diameter 1 5 . 



Collected by J. Donnell Smith in Florida. 



This species is nearest St. pusillum, but unlike it in the 

 proportionately longer cell, the almost smooth and sulcate 

 membrane, and the crenulate sides. 



St. encisum, Wolle. Plate XLI, figs. 12-14. 



Cytioderm granulate, margins serrately toothed ; semicells in 

 t'n>iit view, cuneate, base broad, sides diverging to a convex top ; 

 the upper portion on each side produced into short, obtuse, taper- 

 ing processes j end view, five or six radiate; rav- with broad 



base, somewhat tapering to the obtuse apices; sides serratel) 



toothed ; the ray- separated at their broad base by an acute- 

 angled, or linear incision. 

 Diameter 36-40 ,". 



Principally from Splitrock and other ponds of New Jersey. 



St. pulchrum and St. distentum have a leading feature of 

 this species the incision, or notch between the bases of the 

 rays, but they are separated by the -month membrane and 

 differently formed notch. 



St. Meriani, Reinsch. Plate XLVJ, figs. 17-19. 



Cells in front view subrectangular, roughly granulate, 

 slightly constricted in the middle ; semicells somewhat en- 

 larged in the upper portion ; sometimes -lightly constricted 



