EUGLENOIDINA 303 



bodies; a nucleus; holozoic or saprozoic. Many species in fresh water 

 and a few in salt water. Species (Shawhan and Jahn, 1947). 



P. mediocanellata S. (Fig. 122, d). Ovoid with longitudinal fur- 

 rows on two sides; flageHum about as long as the body; 21-26/x long. 



Genus Rhabdomonas Fresenius. Rigid body, cylindrical and not 

 flattened, more or less arched ; pellicle longitudinally ridged ; a flag- 

 ellum through aperture at the anterior tip; fresh water (Pringsheim, 

 1942). Species (Pascher, 1925); relation to Menoidium (Pringsheim, 

 1942). 



R. incurva F. (Figs. 69, 122, e). Banana-shaped; longitudinal ridges 

 conspicuous; flagellum as long as the body; 15-25^ by 7-8 n (Hall, 

 1923); 13-15/x by 5-7;u (Hollande, 1952a); common in standing 

 water. 



Genus Scytomonas Stein. Oval or pyriform, with a delicate pel- 

 licle; a single flagellum; a contractile vacuole with a reservoir; 

 holozoic on bacteria; longitudinal fission in motile stage; stagnant 

 water and coprozoic. 



S. pusilla S. (Fig. 122, /). About 15/x long. Cytology (Schiissler, 

 1917). 



Genus Copromonas Dobell. Elongate ovoid; with a single flagel- 

 lum; a small cytostome at anterior end; holozoic on bacteria; per- 

 manent fusion followed by encystment (p. 183); coprozoic in faecal 

 matters of frog, toad, and man; several authors hold that this genus 

 is probably identical with Scytomonas which was incompletely de- 

 scribed by Stein. 



C. subtilis D. (Fig. 78). 7-20ju long. Golgi body (Gatenby and 

 Singh, 1938). 



Family 3 Anisonemidae Schewiakoff 



Colorless body plastic or rigid with a variously marked pellicle; 

 2 flagella, one directed anteriorly and the other usually posteriorly; 

 contractile vacuoles and reservoir; stigma absent; paramylon bodies 

 usually present; free-swimming or creeping. 



Genus Anisonema Dujardin. Generally ovoid; more or less flat- 

 tened; asymmetrical; plastic or rigid; a slit-like ventral furrow; 

 flagella at anterior end; cytopharynx long; contractile vacuole an- 

 terior; nucleus posterior; in fresh water. Several species. 



A. acinus D. (Fig. 123, a). Rigid; oval; somewhat flattened; pel- 

 licle slightly striated; 25-40m by 16-22/x. 



A. truncatum Stein (Fig. 123, b). Rigid; elongate ovoid: 60 m by 

 20/x. 



A. emarginatum Stokes (Fig. 123, c). Rigid; 14/x long; flagella long. 



