WISCONSIN PHYTOPLANKTON 91 



The dimensions of the alga as I have found it agree well with the 

 variety major W. & G. S. West, which was described at the same time 

 as the type, but since the dimensions of Australian specimens which 

 G. S. West referred to the type are those of the variety major I feel 

 that the variety should not be recognized. 



29. Staurastrum floriferum W. & G. S. West. PI. 74, Figs. 12-18. 



Trans. Linn. Soc. 2nd. Ser. Bot. 5: 267, pi. 18, fig. 1. 1896. 



Cells of medium size, breadth (with processes) two to three times 

 the length, fairly deeply constricted, sinus widely open and with an 

 acute apex, isthmus fairly narrow; semicells obversely trapeziform, 

 with the ventral margins slightly convex and the dorsal margin flat- 

 tened, cell apex with a row of emarginate verrucae ; angles continued 

 in long horizontal processes with subparallel sides, superior margin 

 of processes with short acute spines, inferior margin of processes gen- 

 erally with shorter similar spines, ends of processes with three fairly 

 stout short divergent spines, processes parallel to divergent. Vertical 

 view triangular, cell body with straight sides and an intramarginal 

 hexagonal ring of emarginate verrucae (two within each lateral mar- 

 gin) ; angles continued in long hollow slightly tapering processes with 

 faintly undulate lateral margins, basal portion of processes with a 

 double row of spines, apical portion with a single row, ends of 

 processes with three stout divergent spines. Chloroplast with a small 

 central mass and two long parallel plates running to each angle and 

 continuing for a short distance into the processes; pyrenoid single 

 and central. (Facultative planktont.) 



Zygospores unknown. 



Cells 23-44 fi long with processes, 22-26 jj. long without processes ; 

 breadth with processes 52-86 /x, without processes 19-26 /a ; breadth at 

 isthmus 6.5-8 /x. 



Lake of the Woods (rrr). Paddock (rrr), Pokegama (r). 



This alga has not been reported since it was described twenty -five 

 years ago. I have found it at three stations, though never in any great 

 quantity. There is more variation in both the amount of divergence 

 of the processes and the dimensions of the cells than W. & G. S. West 

 describe. 



The length of the processes in the individuals from Pokegama lake 

 was somewhat greater than that found in the other examples (Figs. 

 16-18) and the front view of these individuals suggests S. anatinum 

 var. longihrachiatum but the ornamentation of the top view is quite 

 distinctive and the two need never be confused. 



30. Staurastrum Bullardii sp. nov. PI. 74, Figs. 19-23; PI. 75, 



Figs. 1-3. 



Cells fairly large, breadth (with processes) equal to or slightly 

 greater than the length, deeply constricted, sinus widely open and 



