836 PROTOZOOLOGY 



U. citrina K. (Fig. 355, g). Elongate; flexible; ectoplasm with 

 pale-yellow ringed bodies which give the organism yellowish color; 

 marginals discontinuous posteriorly; 2 contractile vacuoles near 

 left border; 150-25CV long; salt water. 



Genus Strongylidium Sterki. 2-5 ventral rows of cirri; marginals 

 spirally arranged; 3-6 frontals; 2 or more macro nuclei; fresh or salt 

 water. Many species. 



S. californicum Kahl (Fig. 355, h). 4-5 frontals; macronuclei about 

 30 in number; 4 micronuclei; contractile vacuole with short canals; 

 about 250/* long; fresh water among vegetation. 



Genus Stichotricha Perty. Slender ovoid or fusiform; peristome- 

 bearing part narrowed; not flexible; usually 4 spiral rows of cirri; 

 sometimes tube-dwelling, and then in groups; fresh or salt water. 

 Many species. 



S. secunda P. (Fig. 355, i). 130-200/i long; in fresh water. 



S. intermedia Froud (Fig. 355, J - )- Solitary; non-loricate; 40-170/x 

 long, 2/5 of which is a bent proboscis; two rows of body cilia; two 

 rows of dorsal cilia, 5/t long; among Lemna in fresh water (Froud, 

 1949). 



Genus Chaetospira Lachmann. Similar to Stichotricha; but peri- 

 stome-bearing part flexible; fresh or salt water. 



C. mulleri L. (Fig. 355, k). Flask-shaped, 60-200 /i long, in a lorica; 

 cytostome at the base of proboscis; a single (two or more) micronu- 

 cleus; macronucleus in two to eight parts; ingested diatoms lose 

 color in 10 minutes; Bodo is immobilized in less than one minute; 

 binary fission; the anterior individual remains in the lorica, while 

 the posterior individual (averaging 46 /i long) swims away and sooner 

 or later becomes attached to substrate; cysts pyriform, 35-55/x by 

 15-20/i ; among Lemna in fresh water (Froud, 1949). 



Genus Urostyla Ehrenberg. Ellipsoid; flexible; ends rounded; 

 flattened ventral surface with 4-10 rows of small cirri and 2 mar- 

 ginal rows; 3 or more frontals; 5-12 anals; macronucleus a single 

 body or in many parts; fresh or salt water. Numerous species. 



U. grandis E. (Figs. 49; 355, I). 300-400/t long; macronucleus in 

 100 or more parts; 6-8 micronuclei; fresh water. Nuclei (Raabe, 

 1946, 1947) (p. 165). 



U. trichogaster Stokes (Fig. 355, m). 250-330/t long; fresh water. 



U. caudata S. (Fig. 356, a). Elongate ellipsoid; flexible; narrowed 

 anterior part bent to left; peristome 1/3 the body length; macro- 

 nucleus in many parts; contractile vacuoles near left margin; about 

 600/* long; fresh water with sphagnum. 



