676 PROTOZOOLOGY 



anals; marginals uninterrupted; 4-8 macronuclei; contractile vacu- 

 ole ; fresh water. One species. 



0. grandis S. (Fig. 317,/). 100-300/x long. 



Genus Onychodromopsis Stokes. Similar to Onychodromus ; but 

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

 water. One species. 



O.fiexilis S. (Fig. 317, g). 90-125m 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) (Fig. 317, h). Subcircular to elliptical; average 

 dimensions 91m by 52ju; 9 f rontal-ventrals ; aboral surface with 6 pro- 

 minent ridges with rows of bristles embedded in rosettes of granules; 

 peristome narrow; peristomal plate small triangle; macronucleus 

 simple C-form band; micronucleus near anterior-left end; membra- 

 nellae straight; posterior end of cytopharynx anterior to, and to left 

 of, the fifth anal cirrus; post-pharyngeal sac; fresh and brackish 

 water. 



E. eurystomus Wrzesniowski (Fig. 317, i). Elongated ellipsoid; 

 length 100-195m; average dimensions 138/x by 78^; 9 f rontal-ventrals ; 

 no aboral ridges, but 7 rows of bristles; peristome wide, deep; peri- 

 stomal depression sigmoid; membranellae forming sigmoid curve; 

 end of cytopharynx far to left and anterior to the fifth anal cirrus; 

 post-pharyngeal sac; macronucleus 3-shaped; micronucleus near 

 flattened anterior corner of macronucleus ; fresh and brackish water. 



E. woodruffi Gaw (Fig. 317, j). Oval; length 120-165^; average 

 dimensions 140^ by 90//; 9 f rontal-ventrals ; aboral surface often 

 with 8 low ridges; peristome wide, with a small peristomal plate; end 

 of cytopharynx almost below the median ridge; 4th ridge between 

 anal cirri often extends to anterior end of body ; post-pharyngeal sac ; 

 macronucleus consistently T-shaped; micronucleus anterior-right; 

 brackish (with salinity 2.30 parts of salt per 1000) and fresh water. 



E. aediculatus Pierson (Fig. 317, k). Elliptical; length 110-165^; 

 average dimensions 132/x by 84/i; 9 f rontal-ventrals ; aboral surface 

 usually without ridges, but with about 6 rows of bristles; peristome 

 narrow; peristomal plate long triangular, drawn out posteriorly; a 

 niche midway on the right border of peristome; anal cirri often form 



