hypocone and reaching the posterior pole; cells 20-25/x in diameter, 

 30-35/t long. 



The plates are very inconspicuous in the specimens seen and their 

 assignment is questionably made on the basis of present information. 

 G. Penardiforme is described as having 4 intercalary and 6 precin- 

 gular plates in the epitheca, 5 postcingular and 2 antapical plates 

 in the hypotheca; the cell with or v^ithout chromatophores. 



Not uncommon; in several soft water lakes, ponds, and swamps. 

 Wis. 



Glenodinium pulvisculus (Ehrenb.) Stein 1883, III, part 2 



PI. 90, Figs. 17, 18 



Cells ovate to subglobose, the epicone and hypocone both broadly , 

 rounded at the poles; transverse furrow winding to the left; longi- 

 tudinal furrow extending into the epicone and posteriorly almost to 

 the pole of the hypocone; chromatophores numerous, golden-brown 

 bodies; cells 13-19-(29))a in diameter, 23^5/. long. 



The plates of the theca of this species are as yet incompletely 

 known, and the assignment to the genus Glenodinium is question- 

 able. As suggested by Eddy (1930) it may belong to Gymnodinium. 



Tychoplankter. Mich., Wis. 



Glenodinium quadridens (Stein) Schiller 1935-1937, p. 117 



PI. 90, Figs. 19, 20 



Cells ovate, the epicone apiculate, the hypocone broadly rounded 

 and furnished with 3-5 short, sharp spines, laterally and posteriorly 

 placed; transverse furrow not spiral, usually median and equally 

 dividing the cell; longitudinal furrow extending into the epicone, 

 widening posteriorly and reaching the apex of the hypocone; 

 epitheca with 1 apical, 5 intercalary, and 7 precingular plates; 

 hypotheca with 5 postcingular and 2 antapical plates with a stout 

 spine on each; cells 20S5n in diameter, 24-30/a long. 



Tychoplankter. Wis. 



HEMWINIUM Stein 1883,p. 90 



Cells unsymmetrically ellipsoid, much flattened dorsiventrally, 

 both poles broadly rounded, the anterior less so and somewhat 

 cone-shaped; transverse furrow incomplete, spirally descending to 

 the left; membrane covered by a very thin theca in which there 

 are indistinctly marked areolate plates; epitheca with 6 apical, 

 6 precingular plates; hypotheca with 5 postcingular, 1 intercalary, 



[430] 



