580 PROTOZOOLOGY 



B. perisimim P. (Fig. 262, h). 80-1 20/x long; elongate oval; 

 posterior end pointed; left peristomal edge sigmoid; preoral mem- 

 brane large; macronucleus in 3-7 parts; rose-colored; fresh water 

 among decaying vegetation. 



B. steini Kahl (Fig. 262, i). 80-200^ long; macronucleus ovoid; 

 reddish to colorless; fresh water in sphagnum. 



B. undulans Stein. 150-300^ long; macronucleus in 2 parts; 

 undulating membrane long; cytopharynx directed posteriorly; 

 fresh water among decaying vegetation. Moore (1934) studied its 

 contractile vacuole and Giese (1938) observed the influence of 

 light upon its coloration (p. 37). 



Genus Protocruzia Faria, da Cunha et Pinto. Peristome does 

 not turn right, leads directly into cytostome; convex left side not 

 ciliated, but bears bristles; flat right side with 3-5 faintly marked 

 ciliary rows; peristome begins at pointed anterior end and ex- 

 tends 1/4-1/3 the body length; cytopharynx (?); macronucleus 

 simple; contractile vacuole subterminal; salt water. 



P. pigerrima (Cohn) (Fig. 262, j). About 20m (da Cunha); 50- 

 60/i long (Kahl); peristome 1/4-1/3 the body length; salt water. 



Genus Phacodinium Prowazek. Oval; marked grooves on body 

 surface; cilia in cirrus-like fused groups; peristome long on left 

 margin; cytostome posterior; contractile vacuole terminal; mac- 

 ronucleus horseshoe-shape; 5-9 micronuclei; fresh water. One 

 species. 



P. metchnicoffi (Certes) (Fig. 262, k). About lOOw long. 



Genus Pseudoblepharisma Kahl. Body form intermediate be- 

 tween Spirostomum and Blepharisvia ; right peristomal edge with 

 2 rows of cilia; fresh water. 



P. tenuis K. (Fig. 263, h). 100-200^ long. 



Genus ParablepharismaKahl. Similar to Blepharisma; but peri- 

 stome-bearing anterior half narrowed neck-like and pointed; ec- 

 toplasm covered with gelatinous layer in which symbiotic bacteria 

 are imbedded; salt water. 



P. pellitum K. (Fig. 263, i). 120-180^ long. 



Genus Nyctotherus Leidy. Oval or reniform; compressed; peri- 

 stome begins at anterior end, slightly turns to right and ends in 

 cytostome located midway between the ends; cytopharynx runs 

 dorsally and posteriorly, a long tube with undulating membrane; 

 ciliary rows longitudinal and close-set; massive macronucleus in 

 anterior half with a micronucleus ; in some, nuclei are suspended 



