Smith—Phytoplankton of the Muskoka Region. 349 
typical A. quiriferus, but the retuse apices of the semicells are 
not found in S. jaculiferum. 
Arthrodesmus subulatus Ktz. 
Big Dudley (rrr), Muskoka (rr), Vernon (rr). 
STAURASTRUM Meyen 1829 
Staurastrum muticum Breb. Pl. X, figs. 21, 22. 
Length 27.5 n; breadth 23-26 breadth isthmus 6 y. 
Butterfly (sss), Harbon (rrr). 
Staurastrum grande Bulnh. 
Rowley (rrr). 
Staurastrum cuspidatum Breb. 
Big Dudley (rrr), Black (rrr), Butterfly (rrr), Gull (1) (rrr), Joseph 
(rrr), Lake of Bays (rrr), Otter (rr), Portage (rrr), Rowley (sss). 
var. divergens Nords. 
Brush (rrr). 
var. canadense var. nov. PI. X, figs. 23, 24. 
Isthmus of cells with a slight constriction at the point of origin 
of new semicells, 
Length 22-25 breadth (without spines) 22-24 y, (with spines) 
45-58 fi ; breadth isthmus 5 y. 
Clear (2) (rrr), Echo (rrr), Muskoka (rrr), Pine (r), Rosseau (rrr), 
Round (1) (rrr), Strange (rrr). 
Staurastrum dejectum Breb. 
Burned Rock (rrr), Echo (rrr), Harbon (rrr), Henshaw (rrr), Loon 
(r), Muskoka (rrr), Round (2) (rr), Rowley (r). 
var. Tellami W. & G. S. West 
Portage (rr). 
Staurastrum curvatum W. West 
Black (1) (rrr), Burned Rock (rrr), Butterfly (rr), Harbon (rrr), 
Loon (rr), Muldrew (sss), Muskoka (r), Nelson (rrr), Pennsylvania 
(rrr), Round (2) (rrr), Rowley (r), Silver (2) (rrr), Vernon (ss). 
Staurastrum megacanthum Lund. 
Gull (2) (rrr), Lake of Bays (rrr), Long (1) (rrr), Long (2) (rr), 
Nelson (rrr), Strange (rrr). 
