PHYTOMONADINA 277 



stigma; a single nucleus; 2 contractile vacuoles anterior; asexual 

 reproduction and palmella formation; sexual reproduction isogamy 

 or anisogamy; fresh water. Numerous species (Pascher, 1921, 1925, 

 1929, 1930, 1932: Skvortzow, 1929; Pringsheim, 1930; Pascher and 

 Jahoda, 1928; Moewus, 1932, 1933; Gerloff, 1940); variation (Moe- 

 wus, 1933) ; sexual development (Moewus, 1933a) ; variation (p. 223) ; 

 genetics (p. 231). 



C. monadina Stein (Fig. 112, a-c). 15-30/x long; fresh water; 

 Landacre noted that the organisms obstructed the sand filters used in 

 connection with a septic tank, together with the diatom Navicula. 



C. angulosa Dill. About 20^u by 12-15/z; fresh water. 



C. epiphytica Smith (Fig. 112, d). 8-9/j, by 7-8/*; in freshwater lakes. 



C. globosa Snow (Fig. 112, e). Spheroid or ellipsoid; 5-7 n in dia- 

 meter; in freshwater lakes. 



C. gracilis S. (Fig. 112,/). 10-13/x by 5-7 n; fresh water. 



Genus Haematococcus Agardh (Sphaerella Sommerfeldt). Sphe- 

 roidal or ovoid with a gelatinous envelope ; chromatophore peripheral 

 and reticulate, with 2-8 scattered pyrenoids; several contractile 

 vacuoles; haematochrome frequently abundant in both motile and 

 encysted stages; asexual reproduction in motile form; sexual repro- 

 duction isogamy; fresh water. 



H. pluvialis (Flotow) (Figs. 42; 112, g). Spherical; with numerous 

 radial cytoplasmic processes; chromatophore U-shape in optical sec- 

 tion; body 8-50m, stigma fusiform, lateral; fresh water. Reichenow 

 (1909) noticed the disappearance of haematochrome if the culture 

 medium was rich in nitrogen and phosphorus. In bacteria-free cul- 

 tures, Elliott (1934) observed 4 types of cells: large and small flagel- 

 lates, palmella stage and haemato cysts. Large flagellates predominate 

 in liquid cultures, but when conditions become unfavorable, palmella 

 stage and then haematocysts develop. When the cysts are placed in 

 a favorable environment after exposure to freezing, desiccation, etc., 

 they give rise to small flagellates which grow into palmella stage or 

 large flagellates. No syngamy of small flagellates was noticed. Hae- 

 matochrome appears during certain phases in sunlight and its ap- 

 pearance is accelerated by sodium acetate under sunlight. Sexuality 

 (Schulze, 1927). 



Genus Sphaerellopsis Korschikoff (Chlamydococcus Stein). With 

 gelatinous envelope which is usually ellipsoid with rounded ends; 

 body elongate fusiform or pyriform, no protoplasmic processes to 

 envelope; 2 equally long flagella; chromatophore large; a pyrenoid; 

 with or without stigma; nucleus in anterior half; 2 contractile vacu- 

 oles; fresh water. 



