352 Wisconsin Academy of Sciences, Arts, and Letters. 
specific recognition. It differs from S. grallatorium in the smooth 
convex apex of the semicells, the deeper constriction at the isthmus, 
and the denticulation of the arms. I have not noted the typical 
organism in Ontario although I have it from the plankton of Wis¬ 
consin lakes. 
var. longiradiatum var. nov. PL XI, figs. 10, 11. 
Semicells with longer, gracefully divergent processes; wall some¬ 
what thicker at the apex of semicells than in other portions. 
Length (without processes) 30 ft, (with processes) 80-95 /x ; 
breadth (without processes) 25 ft, (with processes) 132-150 ft; 
breadth isthmus 7.5-8.5 ft. 
Gull (1) (rr), Silver (1) (rrr). 
var. triradiatum var. nov. PL XI, figs. 12, 13. 
Semicells triangular, not flattened, with the angles produced 
into long, very slightly tapering processes with undulate sides. 
Apex of semicells with walls slightly thickened. 
Length (without processes) 25 ft, (with processes) 62-68 ft; 
breadth (without processes) 17.5-20 ft, (with processes) 60-70 ft; 
breadth isthmus 7.5-10 ft. 
Butterfly (ss). 
Staurastrum aspinosum var. verrucosum var. nov. Pl. XI, 
figs. 17-20. 
Semicells with two apical verrucae between each adjacent pair 
of the three processes. Arms of semicells lying above one an¬ 
other and not alternately arranged. 
Length (without processes) 25-28 ft, (with processes) 50-64 ft; 
breadth (without processes) 22 ft, (with processes) 65-75 ft; 
breadth isthmus 10 ft. 
©lack (1) (sss), Burned Rock (rr), Gull (1) (sss), Gull (2) (rr), 
Hamer (sss), Joseph (rrr), Long (1) (rrr), Muldrew (rr), Portage (rrr), 
Silver (2) (sss). 
The processes of this variety possess the peculiar spines that 
characterize the species but they are laxer than the type. The 
apical verrucae found in this variety are not mentioned by Wolle. 
Staurastrum paradoxum Meyen. 
Brush (rr), Clear (1) (rrr), Thompson (rrr). 
