STAURASTRUM. 125 



St. inconspicuum, Nbrd. Plate LI II, figs. I, 5. 



Small, about equal in Length and breadth ; very indistinctly 

 or not at all constricted in the middle : semicells subquad- 

 rangular, cud- usually slightly retuse ; superior angles pro- 

 duced obliquely into a geniculate arm with a truncate cud; 

 cud view lour radiate, sides concave. Membrane smooth or 

 finely punctate. 



Diameter 14-16 //. 



Occasional in pond-. New Jersey. 



St. pseudopachyrhynchum, Wolle. Plate LI, figs. 32-35. 



Small, -i tli or imperfectly punctate, slightly longer than 



broad, deeply constricted ; sinus wide, base rounded; semi- 

 cells subcuneate; from a narrow base somewhal undulately 

 widened to the broad, subtruncate nd : an^lc- rather broadly 

 rounded, with a slight constriction mar the apex. End view 

 tri- or quadrangular ; sides sinuate, [sthmus about one-fourth 



the diameter of cell. 



Diameter 20-24 ,".: length 22-25 ,". 



Pond, Spring Lake, N. J. 



I found this new species only in one pond, but numerous; 

 it hears the appearance of a relation to a Brazil plant de- 

 scribed by Nordstedt, as St. Clepsydra, and also to a Spitz- 

 bergen species by the same author, St. pachyrhynchum. The 

 name applies well to the new form, although only two-thirds 

 the size and proportionately Longer; the sides also, end view, 

 are not "slightly concave," but deeply -innate. 



SE> TH'N II. 

 (V riODEKM .i; \ni I. \i: OB VERR1 I OBE. 



St. margaritaceum, Ehrb. Plate XLL figs. 31-35. 



Semicells in front view, subelliptic, rough with pearly gran- 

 ules; outer margin convex, produced at each side into a more 

 or less attenuate, short process, having the granules in trans- 

 verse lines; bluut and entire at the apex. End view circular, 

 bordered by from 4-6, rarely 7, short, narrow, obtuse, gran- 

 ulate marginal rays. 



Diameter 30-35 ;/.. 



Found in all States explored, from Rhode Island to Florida. 



