124 HANDBOOK OF PROTOZOOLOGY 



Body colorless, flask-shaped; a funnel-like neck; posterior region 

 stout. A single flagellum protrudes from the funnel and reaches 

 inward the posterior third of the body. Salt or fresh water. 



Urceolus cyclostomus (Stein) (Fig. 42, b). Body about 50 

 microns long. Fresh water. 



Genus Peranema Dujardin. Body oblong, with a broad, 

 rounded or truncate posterior end during locomotion; highly 

 changeable when stationary. The delicate pellicle shows a fine 

 striation. The long flagellum tapers toward the free end and 

 vibrates. Nucleus central; several contractile vacuoles. Sapro- 

 zoic. In stagnant water; often in hay infusion. 



Peranema trichophorum (Ehrenberg) (Fig. 42, c). Body 60 

 to 70 microns long. In stagnant water, infusion, etc. Common. 



Genus Petalomonas Stein. Colorless body constant in 

 form ; pellicle often with longitudinal keels on one side. A single 

 flagellum. Holozoic or saprozoic. Cytostome at the anterior 

 end; cytopharynx fairly deep. Fresh water. 



Petalomonas ervilia Stein (Fig. 42, d). Body about 45 mi- 

 crons long. 



Genus Menoidium Perty. Body curved in a crescent or 

 S-form. With a definite pellicle and a single flagellum. 



Menoidium incurvum (Fresenius) (Fig. 42, e). About 15 to 

 25 microns long. Fresh water. 



Genus Scytomonas Stein. Body oval or pyriform, with a 

 delicate pellicle; a single flagellum. A contractile vacuole with 

 a reservoir. Holozoic on bacteria. Longitudinal fission in 

 motile stage. Coprozoic. 



Scytomonas pusilla Stein (Fig. 42,/). About 15 microns long. 



Genus Copromonas Dobell. Body elongated ovoid, with a 

 single flagellum. A small cytostome at the anterior end. 

 Holozoic on bacteria. Copulation is followed by an encyst- 

 ment (p. 52). Coprozoic in fecal matters of frog, toad, and man. 

 Several authors hold that this genus is probably identical with 

 Scytomonas which was indistinctly described by Stein. 



Copromonas suhtilis Dobell (Fig. 24, a). Body 7 to 20 

 microns long. 



Family 3 Heteronemidae Calkins 



Colorless body may be plastic or rigid with a variously 

 marked pellicle. Flagella two in number, one directed an- 



