350 Wisconsin Academy of Sciences, Arts, and Letters. 
var. scoticum W. & G. S. West 
Gull (1) (rr), Hamer (rrr), Silver (1) (rr). 
Staurastrum Brebissonii var. paucispinum var. nov. PL X, 
fig. 25; PL XI, figs. 1-5. 
Cells small, with three or four large spines at the angles and 
one or two small spines on the apex of the semicells just within 
the angles. 
Length 31-34 fx; breadth (without spines) 32-40 /*, (with 
spines) 45-52 /x; breadth isthmus 8.5-10 /x. 
Black (1) (ss), Burned Rock (rrr), Echo (rrr), Muldrew (rrr). 
This variety is quite similar to the variety heterocanthum but 
differs in the possession of only one or two smaller spines at the 
cell angles and in a general occurrence of four large spines at the 
angles. 
Staurastrum setigerum var. brevispinum var. nov. Pl. XI, 
figs. 6-8. 
Semicells with several stout aculei at the corners and with two 
rows of 6-8 short aculei across the median portion of the semi- 
cell. Vertical view with one row of the smaller spines in profile 
on the margin and an inner row of smaller spines following 
the gentle concavity of cell margins. Large spines at the angles 
as in the front view. 
Length 35-40 fx; breadth (without spines) 37-^3 fx, (with 
spines) 47-55 /x; breadth isthmus 12-14 fx. 
Gull (1) (rrr), Gull (2) (rrr), Pennsylvania (rrr). Pine (rr). Rowlev 
(rrr), Silver (rr), Vernon (rr). 
Staurastrum minnesotense Wolle. Pl. XI, fig. 9. 
Muldrew (rrr), Otter (rrr). 
The Wests (Trans. Linn. Soc. 2 Ser. Bot. 5; 260. Pl. 17, fig. 
15, 1896) infer that regular specimens with pairs of spines in each 
semicell are quite rare. Practically all specimens collected in On¬ 
tario possessed the six stout and twelve delicate spines on each 
semicell. The chief variation from the type is the lack of some 
of the delicate spines on the sides of the semicells. 
Staurastrum subnudibrachiatum W. & G. S. West 
Brush (rr). Burned Rock (rrr), Gull (1) (rrr), Joseph (rrr), Loon 
(r), Portage (r), Silver (2) (r). 
