106 WISCONSIN PHYTOPLANETON 



Cells 55-86 fi long with processes, 47-52 /t long without processes ; 

 breadth with processes 98-125 ix, without processes 22-30 /x, ; breadth 

 at isthmus 9-10.5 ft. 



Bass (rrr), Beaverdam (rrr), Crab (rr), Cranberry (rrr), Crawling Stone (sss), 

 Duck (rrr), George (r), Grindstone (rr), Lac Court Oreilles (r). Long (rr), Ee- 

 serve (r), Whitefish (sss). 



The general outline of the semicells in this variety is that of 

 8. Johnsonii except for the basal swelling. The ornamentation of 

 the base is lacking and the apical verrucation is much simpler. In 

 some of the specimens there is a median row of granules on the 

 processes, a feature found in 8. Johnsonii, but not in the closely re- 

 lated 8. leptocladum Nordstedt. 



42. Staurastrum natator W. "West. PL 79, Fig. 12. 



Jour. Linn. Soc. Bot. 29: 183, pi. 23, fig. 14. 1892. 



Cells of medium size, length (without processes) about twice the 

 breadth, slightly constricted, sinus a small semicircular depression, 

 isthmus fairly broad; semicells subrectangular to subtrapeziform, 

 with the lateral margins slightly convex and the apex straight; cen- 

 tral portion of the apex with three tridenticulate verrucae in which 

 the central spine is more prominent than the other two ; angles of 

 cells continued in long slightly curved processes that are ornamented 

 with concentric rings of granules, ends of processes with three small 



Fig. 12. Staurastrum natator W. West (xSOO). From type material collected 

 by William West in the small lakes between Clifden and Eoundstone, Galway, 

 Ireland. 



subdivergent spines, processes divergent ; central area of body of 

 semicells with a protuberance bearing a ring of 6-8 granules that en- 

 close one or two similar granules, basal portion of semicells with a 

 transverse row of minute granules, 6-8 of which are visible in a front 

 view of the cell. Vertical view compressed and subelliptic, with the 

 transition from the body of the cell to the processes gradual, central 

 portion of the lateral margins with a truncate projection and margins 



