5. Cells pyriform, broadly rounded anteriorly, 



narrowed to a slender stipe below C. pyriformis 



5. Cells broadly ovoid in the lower portion, abruptly narrowed an- 

 teriorly and then extended to form a produced apex C. lageniformis 



Characiopsis acuta ( A. Braun ) Borzi 1894, p. 153 

 PI. 95, Figs. 29-^1 

 Cells ovoid to fusiform or spindle-shaped, on a slender stipe less 

 than the cell body in length, with a basal attaching disc, narrowed 

 anteriorly, sometimes abruptly to a sharp or blunt point; membrane 

 thin, thickened at the apex; chromatophores 1-2 large parietal 

 plates folded along the wall; cells 6-10/x in diameter, 15-28/x long 

 ( including stipe ) . 

 In soft water lake; tychoplanktonic among other algae. Mich., Wis. 



Characiopsis cylindrica (Lambert) Lemmermann 1914, p. 256 



PI. 45, Fig. 19; PI. 94, Figs. 1, 2 

 Cells club-shaped to cylindrical, rounded at the anterior end, 

 tapering posteriorly to a narrow base, scarcely forming a stipe 

 ( nearly sessile ) ; with a basal attaching disc; in reproduction forming 

 8-32 or hundreds of minute bodies which escape through a pore in 

 the apex where there is a thickened plug; chromatophores 2, parietal; 

 cells 9-20fi in diameter, 24-55-(430)/a long. 



Epizoic on Daphnia and other microzoa in small lakes. Wis. 



Characiopsis lageniformis Pascher 1930, p. 444 

 PI. 93, Fig. 31 

 Cells solitary or in small groups, fusiform, broad below and then 

 rather abruptly narrowed to a rounded, cone-shaped apex; narrowed 

 below to a short stipe which has a flattened attaching disc; chromato- 

 phores 2 parietal bands; cells l-llfx in diameter, 20-23/a long. 

 Epiphytic on Trihonema filaments. Wis. 



Characiopsis longipes ( Rab. ) Borzi 1894, p. 152 

 PI. 93, Fig. 32 

 Cells fusiform, straight or curved, apiculate, tapering posteriorly 

 into a long, slender stipe, with a basal attaching disc; chromato- 

 phores 1-2; cells 5-7.5/x in diameter, 40-50)u, long. 



Epiphytic on filamentous algae, including diatoms. Mich., Wis. 



Characiopsis pyriformis (A. Braun) Borzi 1894, p. 153 

 .PI. 93, Figs. 33,34 

 Cells obovoid, apex broadly rounded, base narrowed gradually into 

 a relatively long stipe with a basal attaching disc; chromatophores 



[358] 



