712 PROTOZOOLOGY 



Genus Plagiocampa Schewiakoff. Ovoid, spindle-form or cylin- 

 drical; slightly asymmetrical; cytostome at anterior end in a slit; 

 right ridge thickened and lip-like, with about 8 long cilia; with or 

 without long caudal cilium; fresh or salt water. Several species. 



P. marina Kahl (Fig. 304, /, g). Cylindrical; oval macronucleus 

 central; contractile vacuole terminal; a caudal cilium ; 55-90/* long ; 

 salt water; Florida (Noland). 



Genus Chilophrya Kahl. Ovoid or ellipsoid ; cytostome at anterior 

 end, surrounded by protrusible rods; on one side there is a lip-like 

 ectoplasmic projection; fresh or salt water. 



C. (Prorodon) utahensis (Pack) (Fig. 304, h). Body ellipsoid, some- 

 what asymmetrical; comparatively small number of furrows; cilia- 

 tion uniform; a finger-like process in front of cytostome; macro- 

 nucleus small, central; contractile vacuole terminal; endoplasm 

 with zoochlorellae; encystment common; cysts highly sensitive to 

 light; 50m long; Great Salt Lake, Utah (Pack). 



C. (Urotricha) labiata (Edmondson) (Fig. 304, i). Body ovoid; 

 a lip-like process in front of cytostome; macronucleus oblong, central; 

 contractile vacuole terminal; 30/* long; fresh water. 



Genus Platyophrya Kahl. Compressed; flask-like or elongate 

 ovoid; asymmetrical; dorsal surface convex, ventral surface flat or 

 partly concave; spiral striation; position and direction of cytostome 

 variable; macronucleus round; contractile vacuole terminal; fresh 

 water. 



P. lata K. (Fig. 304, j). Highly compressed; colorless; many 

 striae; on left edge of cytostome 5-6 cirrus-like projections and on 

 right edge many short bristles; 105/z long; fresh water with sphagnum. 



Genus Stephanopogon Entz. Somewhat resembles Platyophrya; 

 compressed; cytostome at anterior extremity which is drawn out; 

 cytostome surrounded by lobed membranous structures; salt water. 



S. colpoda E. (Fig. 304, k). Longitudinal striae on 'neck' 4-8 in 

 number; 2 contractile vacuoles; 50-70/* long; creeping movement; 

 salt water among algae. 



Genus Prorodon Ehrenberg (Rhagadostoma Kahl). Ovoid to 

 cylindrical; ciliation uniform, with sometimes longer caudal cilia; 

 oral basket made up of double trichites which end deep in ectoplasm, 

 oval in cross-section; contractile vacuole terminal; macronucleus 

 massive, spherical or oval; fresh or salt water. Numerous species. 



P. discolor (E.) (Fig. 304, I). Ovoidal; 45-55 ciliary rows; macro- 

 nucleus ellipsoid; micronucleus hemispherical; contractile vacuole 

 terminal; 100-130/* long; fresh water; Kahl (1930) states that it oc- 

 curs also in brackish water containing 2.5 per cent salt; sapropelic 



