574 PROTOZOOLOGY 



Genus Pithothorax Kahl. Slender, barrel-shaped; with firm pellicle; 

 a fairly long caudal bristle', contractile vacuole in posterior half ; cilia- 

 tion coarse and not over entire body surface; resembles somewhat 

 Coleps; fresh water. 



P. ovatus K. (Fig. 272, h). Caudal bristle breaks off easily; body 

 30m long; fresh water among decaying vegetation. 



Genus Rhopalophrya Kahl. Cylindrical; furrows widely separated; 

 slightly asymmetrical; curved ventrally; dorsal surface convex; 

 ventral surface flat or slightly concave; anterior end with 'neck'; 2 

 spherical macro nuclei ; fresh or salt water; sapropelic. 



R. salina Kirby (Fig. 273, a). Cylindrical, tapering gradually to a 

 truncated anterior end, slightly curved ventrally; cilia (6-10^ long) 

 sparsely distributed; 2 macro nuclei, spherical; 29-55ju long; 16-21)u 

 in diameter; in concentrated brine (salts "34.8 per cent"; pH 9.48) 

 from Searles Lake; California. 



Genus Enchelyodon Claparede and Lachmann. Elongated; cy- 

 lindrical, ovoid or flask-shaped; some with head-like prolongation; 

 cyto pharynx with trichites; cilia long at anterior end; fresh or salt 

 water. Several species. 



E. calif ornicus Kahl. 120-130/i long; elongate ovoid to nearly 

 cyhndrical; not distinctly flattened; macro nucleus horseshoe-hke, 

 with a large micro nucleus; in mosses; California. 



Genus Trachelophyllum Claparede and Lachmann. Elongate; flat- 

 tened; flexible, ribbon-like; anterior end neck-like and tip truncate; 

 cyto pharynx narrow, round in cross-section, with trichocysts; ciliary 

 rows widely apart; 2 macronuclei, each with a micronucleus; con- 

 tractile vacuole terminal; fresh or salt water. Several species. 



T. clavatum Stokes (Fig. 272, i). About 200^ long; fresh water. 



Genus Ileonema Stokes {Monomastix Roux). Body flattened; 

 flask-shaped; somewhat similar to Trachelophyllum, but differs by 

 the fact that there is a remarkable flagellum-like process extending 

 from anterior end; cytopharynx with trichocysts; fresh water. 



/. dispar S. (Fig. 273, h). Highly contractile; anterior flagellum 

 half body length, whose basal portion spirally furrowed; cytostome 

 at base of the flagellum; cytopharynx spindle-form with trichites; 2 

 contractile vacuoles and cytopyge posterior; ovoid macronucleus; 

 movement slow creeping; about 120m long; fresh water among algae. 



/. ciliata (Roux) (Fig. 273, c). 75m by 14m; fresh water. 



Genus Trachelocerca Ehrenberg. Elongate, vermiform or flask- 

 shaped; more or less extensible, with drawn-out anterior end; with- 

 out any ring-furrow which marks the 'head' of Lacrymaria, and when 



