STAURASTRUM. 137 



Diameter 33-55 i^. Not frequent. 



The figures on Plate LXIII, represent a form noted as va- 

 riety Notarisii, Rab. Collected in ponds Bamber and Brown '& 

 Mills, N. J. 



St. paniculosum, WoUe. Plate LII, figs. 39, 40. 



Cells hexangular, as long as broad, membrane punctate ^ 

 punetules in radiating lines; semi-cells truncated triangles, 

 angles rounded ; inferior angles furnished with two short, 

 straight aculei; end view triangular with one small aculeus 

 visible on each rounded angle; sides moderately convex. 

 . Diameter 40-50 /<. 



Marsh pools, near Bethlehem, Pa. 



St. Bieneanum, Eab. Yar. elUpticum, Wille. Plate LIII, figs. 

 1,2. 

 Semi-cells elliptic; end view triangular with angles 

 rounded, sides more or less deeply concave; membrane 

 finely punctate, distinctly observable when the cell is empty^ 

 punetules regularly arranged in transverse lines. 

 Diameter 33-38 jj. 



Not numerous, but hitherto found specimens in Minnesota,. 

 Massachusetts, Isew Jersey, Pennsylvania and Florida. 



St. inconspicutjm, Nord. Plate LXIV, figs. 4, 5. 



Small, about equal in length and breadth; very indis- 

 tinctly or not at all constricted in the middle; semi-cells 

 subquadrangular, ends usually slightly retuse; superior 

 angles produced obliquely into a geniculate arm with a 

 truncate end ; end view four radiate, sides concave. Mem- 

 brane smooth or finely punctate. 

 Diameter 14-16 /u. 



Occasional in ponds, New Jersey. 



St. pseudopachyehtnchum, Wolle. Plate LXII, figs. 32-35. 



Small, smooth or imperfectly punctate, slightly longer 

 than broad, deeply constricted ; sinus wide, base rounded ;. 

 semi-cells subcuneate; from a narrow base somewhat undu- 

 lately widened to the broad, subtruncate end ; angles rather 

 broadly rounded, with a slight constriction near the apex. 

 End view tri- or quadrangular; sides sinuate. Isthmus 

 about one-fourth the diameter of cell. 



Diameter 20-24 ju. ; length 22-25 M- 



