172 WISCONSIN PHTTOPLANKTON 



var. RETICULATUM Lagerheim. PI. 47, Figs. 4-7. 

 Ofvers. Kgl. Vet.-Ak. Forh. 89, No. 2: 56, pi. 2, fig. 1. 1882. 



Perforations of coenobe very large, oval. Interior cells sub-cruciate 

 to H-shaped. Sides of projections of marginal cells parallel, projec- 

 tions generally terminating in a tuft of delicate long hyaline setae. 

 (Euplanktont ?). 



Cells 10-20 fi broad, 15-40 /* long. 



Big (rr), Camp (s), Center (s), Chetek (s), Crab (rr), Hill (rr), Hooker 

 (rr), Horse (sss), Island (sss), Kawaguesaga (rr), Little Bear (rr), Little 

 Rice (1) (rr), Lost Bass (r), Loveless (r), Nancy (r), Paddock (rr), Palmer 

 (r), Pardee (r), Pine (2) (rrr), Pokegama (1) (r), Pokegama (3) (ss), 

 Prairie (ss), Reserve (rr), Rice (r), St. Croix (sss), Sishebogema (r), South 

 Turtle (rr), Tenderfoot (rr), Waubesa (rr), Whitefish (rr), Winnebago (rr). 



rar. GRACILLIMUM W. & G. S. West, PI. 47, Figs. 8-11 ; PI. 48, Figs. 1-2. 

 Jour, of Bot. 33: 52. 1895. 



Cells very narrow, never wider than the processes. Body of margi- 

 nal cells curved outwards, with two long, somewhat converging processes 

 that have parallel or slightly convex sides. Interior cells like those of 

 margin but with somewhat shorter processes. Perforations of coenobe 

 very large. (Euplanktont). 



Cells 10-22 /x broad, 12-32 /* long. Diam. 16-celled coenobia 65-140 /*. 



Clam (rr), Pine Tree (sss), Travis (r). 



The perforations of the coenobe and the extension of the processes 

 are the greatest in this variety. The varieties clathratum, reticidatum, 

 and gracillimum are not sharply defined and it is possible, taking the 

 collections as a whole, to arrange a series that grades almost impercept- 

 ibly from the typical form to the variety gracillimum. The individuals 

 from any one lake, however, generally vary within fairly narrow limits 

 so I feel that these varieties should be recognized instead of putting 

 them in one collective species without varieties. 



var. ROTUNDATUM Lucks. PI. 46, Fig. 17. 



Jahrb. d. Westpr. Lehrervereins f. Naturk. 2-3: 31. 1907; Nitardy, Beih. z. 

 Bot. Cent. S2 2 : pi. 9, fig. 11. 1914. 



Projections of marginal cells markedly convex and capitate instead 

 of parallel. (Tychoplanktont). 



Oconomowoc (rrr), Horseshoe (1) (rr). 



