288 



FRESH-WATER BIOLOGY 



142 (141) Body elliptical to ovate, flexible. Three unequal rows of ventral 



cilia; frontal styles numerous. No anal styles. Marginal 



setae uninterrupted Eschaneustyla Stokes. 



Representative species. . . Eschaneustyla brachytona Stokes 1886. 



Anterior extremity slightly curved to the left with a con- 

 striction beneath the front border. Frontal styles about 

 twenty-five in oblique rows. Nucleus not observed. Con- 

 tractile vacuole canal-like along the left-hand border. Length 

 about 200 M- Standing water with dead leaves. 



FIG. 521. Eschaneustyla brachytona. X 200. (After Stokes.) 



143 (134) One or two rows of ventral cilia ...... 144 



144 (145) One row of about seven large ventral cilia. Long border and anal 



cilia ' Balladina Kowalewsky. 



145 (144) Two rows of ventral cilia; body not elongated in front. . . 146 



146 (151) Body prolonged posteriorly into a tail-like process 147 



147(150) Body not flask-shaped. . .'':... 148 



148 (149) No anal styles; body narrow, elongated, sometimes contractile. 



The border setae pushed in on the ventral surface. 



Uroleptus Stein. 

 Representative species. . . . . Uroleptus musculus Miiller 1786. 



Body slightly elastic; tail-like process short, conical. An- 

 terior end curved slightly to the left, the posterior to the 

 right. Frontal styles three or four. Length 200 M- Among 

 aquatic plants. 



FIG. 522. Uroleptus musculus. X 150. (After Conn.) 



149 (148) With a row of seventeen anal styles upon the left side. In other 



respects like Uroleptus Amphisia Sterki. 



150 (146) Body flask-shaped, otherwise very similar to Uroleptus. 



Platytrichotus Stokes. 

 Representative species. . Platytrichotus opisthobolus Stokes 1886. 



Frontal styles five. Nucleus single, posterior. Contractile 

 vacuole single. The posterior tip of the body is changeable 

 in form. It may be bifid, truncate, or rounded. Long hispid 

 bristles are developed from the dorsal surface. Length 190 >*. 

 Among sphagnum. 



FIG. 523. Platytrichotus opisthobolus. X 200. (After Stokes.) 



151 (147) Body not prolonged into a tail-like process. Elongated, rounded at 



both ends. With two uninterrupted rows of cilia on the 



ventral surface Holosticha Wrzesniowski. 



Representative species Holosticha vernalis Stokes 1887. 



Frontal styles five or six. Anal styles from five to eight, 

 usually branched. Dorsal bristles numerous. Nuclei two; 

 contractile vacuole central. Length 190 M- Shallow pools, 

 observed with algae. 



FIG. 524. Holosticha vernalis. X 225. (After Conn.) 



1 5 2 (*33) Ventral cilia setae-like, often in interrupted rows 153 



J 53 ( J 56) Ventral setae in more than one row 154 



