640 PROTOZOOLOGY 



B. duodeni Stein (Fig. 300, d). 70-80^ by 55-60^1 ; in the intestine of 

 the frog. 



B. praeniicleatum Kudo and Meglitsch (Fig. 300, e). 42-127/x long, 

 32-102jLt thick, 25-80ju wide; macronucleus close to anterior end; in 

 the colon of Blatta orientalis. 



Family 2 Metopidae Kahl 



Genus Metopus Claparede and Lachma^n. Body form changeable; 

 when extended oblong or fusiform; peristome conspicuous, slightly 

 spirally diagonal, beginning at the anterior end and reaching the 

 middle of body; when contracted, peristome much spirally coiled; 

 cytopharynx short; body ciliation uniform, longitudinal or in some, 

 spiral; longer cilia at ends; conspicuous contractile vacuole terminal; 

 macronucleus ovoid to elongate; fresh or salt water (sapropelic), 

 some parasitic. Numerous species. 



M. es Muller {M. sigmoides C. and L.) (Figs. 80; 302, a). 120-200^ 

 long; sapropelic. Noland's (1927) study on its conjugation has been 

 described (p. 161). 



M. striatus McMurrich (Fig. 302, h). 80-120^ long; fresh water. 



M. fuscus Kahl (Fig. 302, c). 180-300^ long by OO/x wide and 40m 

 thick; fresh water. 



M. circumlahens Biggar (Fig. 302, d). 70-165^ by 50-75^; in the 

 digestive tract of sea urchins, Diadema setosum and Echinomeiris 

 subangularis; Bermuda (Biggar). Powers observed it in Centrechinus 

 antillarum, etc., at Tortugas. 



Genus Spirorhynchus da Cunha. Fusiform; somewhat flattened; 

 anterior end drawn out and curved toward left; posterior end also 

 drawn out; spiral peristome; cytopharynx small with an undulating 

 membrane; cilia uniformly long; contractile vacuole posterior; longi- 

 tudinally striated; body surface with closely adhering bacteria 

 (Kirby); three spherical macronuclei; micronucleus (?); in brackish 

 water. 



S. verrucosus da C. (Fig. 302, e). 122-140m by 20-22^. Kirby ob- 

 served it in salt marsh with 3 per cent salinity; California. 



Genus Caenomorpha Perty (Gyrocoris Stein). Bell-shaped; car- 

 apaced ectoplasm in some species bears protricho cysts; strong mar- 

 ginal zone of about 8 rows of cilia; 1-2 dorsal rows of longer cilia 

 and a dense spiral field around caudal prolongation; peristome long; 

 cytostome posterior; cytopharynx directed anteriorly; a single 

 elongate or two spherical macronuclei; a micronucleus; fresh or salt 

 water (sapropelic). Several species. 



