SPIROTRICHA, HYPOTRICHA 611 



,S. putrina Stokes (Fig. 276, d). 125-150/i long; fresh water. 



S. notophora S. (Fig. 276, e). About 125yu long; standing water. 



Genus Onychodromus Stein. Not flexible; somewhat rectangu- 

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

 flat, dorsal surface convex; peristome broadly triangular in ven- 

 tral view; 3 frontals; 3 rows of cirri parallel to right edge of 

 peristome; 5-6 anals; marginals uninterrupted; 4-8 macronuclei; 

 contractile vacuole; fresh water. One species. 



0. grandis S. (Fig. 276, /). 100-300^ long. 



Genus Onychodromopsis Stokes. Similar to Onychodromus; 

 but flexible; 6 frontals of which the anterior three are the largest; 

 fresh water. One species. 



0. flexilis S. (Fig. 276, g). 90-1 25m long; standing pond water. 



Family 2 Euplotidae Glaus 



Genus Euplotes Ehrenberg. Inflexible body ovoid; ventral 

 surface flattened, dorsal surface convex; longitudinally ridged; 

 peristome broadly triangular; frontal part of adoral zone lies in 

 flat furrow; 9 or more f rontal-ventrals ; 5 anals; 4 scattered 

 caudals; macronucleus band-like; a micronucleus; contractile 

 vacuole posterior; fresh or salt water. Numerous species. 



E. patella (Miiller) (Figs. 11, a; 12; 17; 51; 276, h, i). 9 frontal- 

 ventrals; polymorphic; about 80-1 50^ long; fresh and salt water 

 (experimentally by Bullington). Its neuromotor system studied 

 by Yocom (1918), Taylor (1920) and Turner (1933) (p. 55-56); 

 macronuclear division, by Turner (1930) (p. 120). 



E. plumipes Stokes (Fig. 276, j). About 125m long; fresh water. 



E. carinatus S. (Fig. 277, a). About 70)U by 50m; fresh water. 



E. charon (Miiller) (Fig. 277, 6). 70-90m long; salt water. 



Genus Euplotidium Noland. Cyhndrical; 9 frontal- ventrals in 

 2 rows toward right; 5 anals; a groove extends backward from 

 oral region to ventral side, in which the left-most anal cirrus lies; 

 peristome opened widely at anterior end, but covered posteriorly 

 by a transparent, curved, flap-like membrane; adoral zone made 

 up of about 80 membranellae; longitudinal ridges (carinae) 3 

 dorsal and 2 lateral; a row of protrichocysts under each carina; 

 a broad zone of protrichocysts in antero-dorsal region; cytoplasm 

 densely granulated; salt water. One species. 



E. agitatum N. (Fig. 277, c, d). 65-95m long; erratic movement 

 rapid; observed in half -dead sponges in Florida. 



