672 PROTOZOOLOGY 



many (up to 26) parts; 2 (1-3) micronuclei; fresh water. 



Genus Uroleptopsis Kahl. Ventrals in 2 uninterrupted rows; salt 

 water. A few species. 



U. citrina K. (Fig. 315, g). Elongate; flexible; ectoplasm with 

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

 marginals discontinuous posteriori}^; 2 contractile vacuoles near 

 left border; 150-250^ long; salt water. 



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

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

 water. Many species. 



S. californicum Kahl (Fig. 315, ^). 4-5 frontals; macronuclei about 

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

 about 250m 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. 315, i). lS0-200fj, long; in fresh water. 



Genus Chaetospira Lachmann. Similar to Stichotricha; but peri- 

 stome-bearing part flexible ; fresh or salt water. 



C. miilleri L. 150-250^ long; in lorica; fresh water. 



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. 47; 315, j). 300-400^ long; macronucleus in 

 100 or more parts; 6-8 micronuclei; fresh water. 



U. trichogaster Stokes (Fig. 315, k). 250-330/1 long; fresh water. 



U. caudata S. (Fig. 316, 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/x long; fresh water with sphagnum. 



Genus Kerona Ehrenberg. Reniform; no caudals; 6 oblique rows 

 of ventral cirri; commensal. One species. 



K. polyporum E. (Fig. 316, 6). 120-200m long; commensal on 

 Hydra. 



Genus Keronopsis Penard. Two ventral rows of cirri reaching 

 frontal field; caudals variable; macronucleus usually in several 

 (rarely 2) parts; fresh or salt water. Numerous species. 



K. rubra (Ehrenberg) (Fig. 316, c). Reddish; 200-300m long; salt 

 water. 



