WISCONSIN PHYTOPLANETON 127 



name is based is quite misleading since the number of setae may vary 

 from one to four. Colonies containing more than sixteen cells have 

 not been observed and the cell arrangement has been quadrate in every 

 ease. 



GOLENKINIA Chodat 1894. 



Cells spherical, normally solitary; occasionally forming temporary 

 colonies. Cell wall thin, sometimes enclosed in a thin gelatinous en- 

 velope. Surface of cell covered with hyaline setae that are slightly 

 tapering but not conspicuously thickened in the lower third. Chloro- 

 plast single, parietal and cup-shaped or entirely filling the cell; pyre- 

 noid single. 



Eeproduction by the formation of autospores. Zoospores have been 

 reported but their formation is doubtful. 



KEY TO THE SPECIES. 



Setae 25-45 fj, long G. RADIATA 



Setae 12-18 /j, long G. PAUCISPINA 



GOLENKINIA RADIATA Chodat. PL 29, Figs. 2-3. 

 Jour, de Bot. 8: 305, pi. 3, figs. 1-24. 1894. 



Cells spherical, solitary, sometimes in temporary colonies of four 

 cells. Entire cell wall covered with long, delicate, hyaline setae. Chlor- 

 oplast single, cup-shaped, parietal ; with one pyrenoid. (Euplanktont) . 



Diam. cells (without setae) 7-15 /*; length setae 25-45 /*. 



Green (2) (rrr), White Ash (rr). 



This and the following Golenkinia species have been made a sub- 

 genus of Micractiniwn by Wille and that terminology followed in the 

 second list but the colonial and solitary habit seem to me sufficiently 

 diverse to warrant generic distinction. 



GOLENKINIA PAUCISPINA W. & G. S. West. PI. 29, Figs. 4-5. 

 Trans. Roy. Irish Acad. 32, Sec. B: 68, pi. 1, flg. 18. 1902. 



Cells solitary, spherical, with few to fairly numerous, short, delicately 

 lapering, hyaline or dark setae. Chloroplast single, completely filling 

 the cell, with one pyrenoid. (Euplanktont). 



Diam. cells (without setae) 15-18 p.; length setae 12-18 /u,. 



Prairie (rr). 



The setae of the cells in Prairie lake were more numerous than the 

 "Wests found them in individuals from the plankton of Lough Neagh, 



