SPIROTRICHA, HYPOTRICHA 609 



tral surface ■wdth more than 2 rows of cirri; 2 marginal rows; 

 frontals undifferentiated; anals; no caudals; salt or fresh water. 

 A few species. 



E. pluvialis Smith (Fig. 275, d). About 375m long; fresh water. 



Genus Holosticha Wrzesniowski. 3 of frontals along anterior 

 margin; 2 ventral and 2 marginal rows of cirri; anals; fresh or 

 salt water. Numerous species. 



H. vernalis Stokes (Fig. 275, e). 7 anals; about 180/x long; shal- 

 low pools with algae. 



H. hymenophora S. (Fig. 275,/). 5 anals; 2 contractile vacuoles; 

 160-200/i long; shallow pools. 



Genus Paraholosticha Kahl. Elongate-oval; flexible; ventral 

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

 frontal margin, posterior to it 2 short rows of cirri; marginals 

 continuous or interrupted at posterior border; fresh water. 



P. herhicola K. (Fig. 275, g). 150-1 90m long; fresh water among 

 algae. 



Genus Trichotaxis Stokes. Similar to Holosticha; but wdth 3 

 rows of ventral cirri; fresh or salt water. 



T. stagnatilis S. (Fig. 275, h). About IGO/x long; elUpsoid; in 

 fresh water among decaying vegetation. 



Genus Ballad3ma Kowalewski. Ellipsoid; frontals not well de- 

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

 dorsal and lateral bristles; fresh water. 



B. elongata Roux (Fig. 275, i). 32-35m by 11-12^; fresh water 

 among plants and detritus. 



Genus Pleurotricha Stein. Oblong to ellipsoid; marginals con- 

 tinuous; 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 ciha; fresh water. 



P. lanceolata (Ehrenberg) (Fig. 275, j). 100^165^ long; 2 

 macro- and 2 micro-nuclei; Manwell (1928) studied its conjuga- 

 tion, division, encystment and nuclear variation. 



Genus Gastrostyla Engelmann. Frontals distributed except 3 

 along the frontal margin; ventrals irregular; 5 anals; macro- 

 nucleus divided into 2-8 parts; fresh or salt water. 



G. muscorum Kahl (Fig. 275, k). 130-200/i 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; 



