104 WISCONSIN PHYTOPLANKTON 



var. siNUATUM Woll. PI. 78, Figs. 12-14. 



Bull. Torr. Bot. CI. 10: 20, pi. 27, fig. 24. 1883. 



Cells with the body much narrower and with the bases of the semi- 

 cells not inflated ; without ornamentation except for an apical notch ; 

 processes arising at the same point and with the same curvature as 

 those of the type but not lying in the same plane. (Euplanktont.) 



Cells 65-88 fi long with processes, 25-29 /a long without processes ; 

 breadth with processes 80-93 ju, without processes 12-15 ]a; breadth 

 at isthmus 7-8 (x ; thickness 10 jx. 



Bass (sss). Grassy (rrr), Lindy (c), Little Doctor (ss). Lynx (rrr), Speese 

 (rrr). 



This variety is unique in the peculiar twisting of the processes 

 and in the nature of the upper portion of the semicells, features which 

 are seen to the best advantage in lateral views of the cells. The 

 identification of the Wisconsin material with Wolle's variety 

 sinuatum is open to question since he based his variety on the diver- 

 gence of the processes and the emargination of the semicell apices. 

 Wolle does not mention the variety in his general work on the Desmids 

 of the United States so, perhaps, decided that it was not worthy 

 of recognition. The front view of our alga is so like that which 

 Wolle gives that it seems better to revive his old name than to try 

 to consider it new. 



The specimens from Blue Gill Lake were not twisted, the four 

 ends of the processes lying in the same plane. The crenulation of 

 the processes is also more marked and the ends are quadrispinate. 

 This form has been given the name planum. Its length with proc- 

 esses is 88 fi, without processes 28 fi; breadth with processes 110 /x, 

 without processes 15 fi, breadth at isthmus 9 /x. (PI. 78, Fig. 15) . 



41. Staurastrum Johnsonii W. & G. S. West. PL 79, Figs. 1-6. 



Trans. Linn. Soc. 2nd. Ser. Bot. 5: 266, pi. 17, fig. 16. 1896. 



Staurastrum leptocladum Johnson non Nordstedt, Bull. Torr. Bot. CI. 21: 288, 

 pi. 211, fig. 2. 1894. 



Cells of medium size, breadth (with processes) about one and a 

 half times the length, slightly constricted, sinus a small semicircular 

 depression, isthmus relatively broad; semicells subcampanulate, with 

 inflated bases and slightly tumid apices, angles continued in long 

 gradually tapering processes that terminate in three divergent spines, 

 superior margin of processes crenulate, inferior margin also erenu- 

 late but with the crenulations less pronounced than those of the supe- 

 rior margin, median area of processes with a row of minute denticu- 

 lations, processes somewhat divergent; body of semicells with two 

 transverse rows of granules on the basal inflation, the row farthest 

 from the isthmus frequently poorly developed and irregular, dorsal 

 portion of body of semicells with a transverse subapical row of 5-7 



