STAURASTRUM. 159 



convex, sides somewhat produced and divided into two large 

 diverging mucros ; margins ornate with large emarginate 

 verrucae, or more or less conspicuous prominences ; in ver- 

 tical aspect three, or more rarely, four or five angled ; angles 

 produced and divided, and sides furnished with spines as in 

 front view. 



Diameter, including aculei, 70-80 yw. 



Bamber Pond, New Jersey. 



The form of the semi-cells is more elliptic than trapezoid, 

 but in other points it is a good representative of Lundell's 

 Swedish plant. 



ST. MONTICULOSUM, Breb. Var. Ufarlum, Nord. Plate LXII, 

 figs. 24-26. 



Semi -cells with a forked spine at each lateral angle, and at 

 the end, two twinned, stout, acute, or furcate prominences ; 

 vertical view usually triangular, angles acute or bifid as the 

 cell is in a horizontal position, or somewhat turned ; sides 

 with four single or two bifid prominences. 



Diameter 38 /v. ; length 33-35 /*. 



Spring Lake, New Jersey. 



The form I found is not the typical plant, but answers the 

 description of Nordstedt's Norway variety, bifarium. 



ST. TRICORNUTUM, Wolle. Plate LVIII, figs. 1, 2. 



Large, as long as wide, smooth, semi -cells broad.-elliptic 

 with angles terminated by three long, stout, colorless, di- 

 verging, subulate spines; vertical view triangular, sides 

 somewhat concave, or sometimes slightly convex, angles ter- 

 minated with three subulate spines. 



Diameter of body 90-100 //. ; with the spines 175-200 yw. 



Frequent in Hammonton and other ponds of southern New 

 Jersey. 



ST. Nov^: C^SAR^E, Wolle. Plate LVIII, figs. 3, 4. 



Cells as long as broad, or somewhat longer, coarsely gran- 

 ulate ; semi-cells in front view elliptic, margins crenulate, 

 angles produced into two long subulate, divergent spines; 

 vertical view quadrangular, at angles somewhat constricted, 

 often producing a mammiform appearance, and drawn out 

 into two, long, subulate spines. 



Diameter without spines 36-40 //. ; with spines 62-70 //. 



This species, hitherto found only in a pond near Hammon- 

 ton, N. J., proves to have a home in Florida also. The plant 



