360 PROTOZOOLOGY 



Genus Dinomonas Kent. Ovate or pyriform, plastic, free-swim- 

 ming; 2 fiagella, equal or sub-equal, inserted at anterior extremity, 

 where large oral aperture, visible only at time of food ingestion, is also 

 located, feeding on other flagellates; in infusions. 



D. vorax K. (Fig. 150, i). Ovoid, anterior end pointed; 15-16ju. 

 long; fiagella longer than body; hay infusion and stagnant water. 



Family 8 Monadidae Stein 



Two unequal fiagella; one primary and the other secondary; swim- 

 ming or attached; 1-2 contractile vacuoles; colony formation fre- 

 quent; free-living. 



Genus Monas Muller (Physomonas Kent). Active and plastic; 

 often attached to foreign objects; small, up to 20m long; fresh and 

 salt water. Some authors hold that this genus should be placed in 

 Chrysomonadina on the same ground mentioned for Oikomonas (p. 

 343). Flagellar movement (Krijgsman, 1925); cyst (Scherffel, 1924); 

 morphology and taxonomy (Reynolds, 1934). 



M. guttula Ehrenberg (Fig. 151, a). Spherical to ovoid; 14-16m 

 long; free-swimming or attached; longer flagellum about 1-2 times 

 body length; cysts 12m in diameter; stagnant water. 



M. elongata (Stokes) (Fig. 151, b). Elongate; about 11m long; free- 

 swimming or attached; anterior end obliquely truncate; fresh water. 



M. socialis (Kent) (Figs. 8, d; 151, c). Spherical; 5-10ju long; 

 among decaying vegetation in fresh water. 



M. vestita (Stokes) (Fig. 151, d). Spherical; about 13.5m in diam- 

 eter; stalk about 40m long; pond water. Reynolds (1934) made a 

 careful study of the organism. 



M. sociabilis Meyer. Body 8-10ju long by 5m; two unequal fiagella; 

 the longer one is as long as the body and the shorter one about one- 

 fourth; 20-50 individuals form a spheroid colony, resembling a 

 detached colony of Anthophysis; polysaprobic. 



Genus Stokesiella Lemmermann. Body attached by a fine cyto- 

 plasmic thread to a delicate and stalked vase-like lorica; 2 contrac- 

 tile vacuoles; fresh water. 



S. dissimilis (Stokes) (Fig. 151, e). Solitary; lorica about 28m long. 



S. leptostoma (S.) (Fig. 151, /). Lorica about 17m long; often in 

 groups; on vegetation. 



Genus Stylobryon Fromentel. Similar to Stokesiella; but colonial ; 

 on algae in fresh water. 



S. abbotti Stokes (Fig. 151, g). Lorica campanulate; about 17m 

 long; main stalk about 100m high; body oval or spheroidal; fiagella 

 short. 



