SPIROTRICHA, HYPOTRICHA 605 



U. caudata (Stokes) (Fig. 273, /). 200-250/i long; pond water. 



Genus Amphisiella Goiirret et Roeser. With a single row of 

 ventrals and 2 marginal rows; salt or fresh water. Several species. 



A. thiophaga (Kahl) (Fig. 273, g). 70-1 00^ long; salt water. 



Genus Eschaneustyla Stokes. Elliptical or ovate; narrow peri- 

 stome 1/3 the body length; frontals numerous, about 22 in addi- 

 tion to 2 at anterior margin; ventrals small and numerous in 3 

 oblique rows; no anals; marginals uninterrupted; contractile 

 vacuole a long canal near left border; fresh water. One species. 



E. hrachytona S. (Fig. 273, h). 170-220m long. 



Genus Gonostomum Sterki (Plagiotricha Kent). Flexible; 8 

 or more frontals; 1-2 oblique ventral rows of short cirri; 4 or 5 

 caudals ; 2 marginal rows ; fresh water. 



G. strenuum (Engelmann) (Fig. 273, i). Elongate; with caudal 

 bristles; about 150^ long; fresh water. 



Genus Hemicyclostyla Stokes. Elongate oval; flexible; ends 

 rounded; 20 or more frontals, arranged in 2 semicircular rows; 

 adoral row begins near center of right side of peristomal field; 

 ventral surface entirely covered with fine cilia; no anals; one or 

 more contractile vacuoles; nucleus distributed; fresh water. 



H. sphagni S. (Fig. 273, j). About 400-500ju long; marsh water 

 with sphagnum. 



Genus Hypotrichidium Ilowaisky. 2 ventral rows of cirri and 

 marginals spirally arranged; peristome large, extends 1/2 the 

 body length, with a large undulating membrane; 2 macro- and 

 micro-nuclei; contractile vacuole anterior-left; fresh water. 



H. conicum I. (Fig. 274, a). 90-150^ long. 



Genus Cladotricha Gajevskaja. Elongate band-form; anterior 

 end rounded, posterior end rounded or attentuated; frontals 

 only 2 featherly cirri; macronucleus spheroidal; micronucleus; 

 without contractile vacuole; salt water, with 5-20 per cent salt 

 content. One species. 



C. koltzowii G. (Fig. 273, k, I). Band-form up to about 200^ 

 long; posteriorly attenuated forms up to about 100/i long. 



Genus Psilotricha Stein. Oval to ellipsoid; frontals and anals 

 undifferentiated; ventrals and marginals long bristles, few; ven- 

 trals in 2 rows and a rudimentary row toward left ; with or v/ithout 

 zoochlorellae; fresh water. A few species. 



P. acuminata S. (Fig. 274, h). 80-100/i long. 



Genus Kahlia Horvath, Frontal margin with 3-4 strong cirri; 

 5-8 ventral longitudinal rows ; marginals ; sapropelic in freshwater. 



