POLYMASTIGINA 



261 



Genus Trimastix Kent. Ovate or pyriform; naked; free- 

 swimming; with a laterally produced membranous border; 3 

 flagella, 1 anterior flagellum vibrating, 2 trailing; salt water. 



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Fig. 121. a, Trimastix marina, X1250 (Kent); b, DaUingeria drys- 

 dali, X2000 (Kent); c, Macromastix lapsa, XloOO (Stokes); d, En- 

 teromonas hominis, X2000 (da Fonseca). 



T. marina K. (Fig. 121, a). About 18)U long; salt water. 



Genus DaUingeria Kent. Free-swimming or attached; with 

 trailing flagella; body small; with drawn-out anterior end; fresh 

 water with decomposed organic matter. 



D. drysdali K. (Fig. 121, b). Small; elongate oval; less than 6/x 

 long; stagnant water. 



Genus Macromastix Stokes. Free-swimming, somewhat like 

 DaUingeria, but anterior region not constricted; 3 flagella from 

 anterior end; one contractile vacuole; fresh water. 



M. lapsa S. (Fig. 121, c). Ovoid; 5. 5m long; anterior flagellum 

 1/2 and trailing flagella 2-3 times body length; pond water. 



Genus Enteromonas da Fonseca. Body globular; 2 anterior 

 flagella and one traihng flagellum. 



E. hominis d. F. (Fig. 121, d). Small, 5-6^ in diameter; in 

 human faeces. 



Genus Mixotricha Sutherland. Large; elongate; anterior tip 

 spirally twisted and motile; posterior end probably eversible; 



