674 PROTOZOOLOGY 



Genus Paraholosticha Kahl. Elongate-oval; flexible; ventral cirri 

 in 2 parallel oblique rows; with a row of stiff cirri along frontal mar- 

 gin, posterior to it 2 short rows of cirri; marginals continuous or 

 interrupted at posterior border; fresh water. 



P. herhicola K. (Fig. 316, g). 150-190m long; fresh water among 

 algae. 



Genus Trichotaxis Stokes. Similar to Holosticha; but with 3 rows 

 of ventral cirri ; fresh or salt water. 



T. stagnatilis S. (Fig. 316, h). About 160^1 long; ellipsoid; in fresh 

 water among decaying vegetation. 



Genus Balladjua Kowalewski. Ellipsoid; frontals not well de- 

 veloped or lacking; 1 ventral and 2 marginal rows of cirri; long 

 dorsal and lateral stiff cirri; fresh water. 



B. elongata Roux (Fig. 316, i). 32-35/x by 11-12/x; fresh water 

 among plants and detritus. 



Genus Pleurotricha Stein. Oblong to ellipsoid; marginals continu- 

 ous; 8 frontals; 3-4 ventrals; 7 anals of which 2 are more posterior; 



2 rows of ventral cirri; between ventrals and marginals 1-3 rows of 

 few coarse cilia; fresh water. 



P. lanceolata (Ehrenberg) (Fig. 316, j). 100-165^ long; 2 macro- 

 and 2 micro-nuclei. Manwell (1928) studied its conjugation, division, 

 encystment and nuclear variation. 



Genus Gastrostyla Engelmann. Frontals distributed except 3 along 

 the frontal margin; ventrals irregular; 5 anals; macronucleus divided 

 into 2-8 parts ; fresh or salt water. 



G. muscorum Kahl (Fig. 316, k). 130-200/x long; macronucleus in 

 8 parts; fresh water in vegetation. 



Genus Stylonychia Ehrenberg. Ovoid to reniform; not flexible; 

 ventral surface flat, dorsal surface convex; 8 frontals; 5 ventrals; 

 5 anals; marginals; 3 caudals; with short dorsal bristles; fresh or salt 

 water. Many species. 



S. mylilus (Miiller) (Fig. 317, h). 100-300)U long; fresh, brackish 

 and salt water. 



S. pustulata E. (Figs. 84; 317, c). About 150m long; fresh water; 

 nuclear changes were studied by Summers (1935). 



S. putrina Stokes (Fig. 317, d). 125-150^ long; fresh water. 



S. notophora S. (Fig. 317, e). About 125/i long; standing water. 



Genus Onychodromus Stein. Not flexible; somewhat rectangular; 

 anterior end truncate, posterior end rounded; ventral surface flat, 

 dorsal surface convex; peristome broadly triangular in ventral view; 



3 frontals; 3 rows of cirri parallel to the right edge of peristome; 5-6 



