454 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
side. The peristome is long and rather narrow and carries an undulating membrane on its right 
margin. Fresh and salt water. 
Amphisia kessleri Wrzes. ’77. Fig. 51. 
Synonyms: Trichoda gibba Muller; Oxytricha gibba Stein ’59; O.SoS? Quen. ’69; 0. kessleri Wrzes. ’77. 
Body elongate, slightly sigmoid and swollen in the center, about 3J times as long as broad; the 
rounded anterior end is turned to the left, the similarly rounded posterior end to the right; both ends 
taper slightly. The peristome is long and narrow, with a distinct adoral zone which appears broken 
in its course. To the right of this adoral zone is a single line of preoral cilia. On the right border 
of the peristome is an undulating membrane. The three frontal cirri form a triangle and the live 
smaller anal cirri form a continuous line with the broken row of ventral cirri. There are two and 
one-half rows of ventral cirri and the marginal cirri are drawn in until they are ventral in position. 
Length 135/; ; greatest width 40/;. 
This variety differs from 0. kessleri as described by Wrzesniowski in having three frontal cirri 
instead of four. Another difference is in the structure of the nuclei and in their position. These 
differences are too minute to warrant a specific name. 0. velox of Quennerstedt is probably the same 
as 0. kessleri, but differs in having three complete rows of ventral cirri. 0. i velox has three frontal cirri 
in a line, thus differing from the Woods Hole form. 
Key to the marine genera of Euplotidx. 
Diagnostic characters: Cilia, as -well as the frontal, marginal, and ventral cirri, very much reduced; the anal cirri, on 
the other hand, are always present. The macronucleus is band-form. 
1. Frontal cirri more than 8 2 
Frontal cirri less than 8 3 
2. Eleven marginal cirri on the left side; 11 frontal cirri Genus Certesia 
Four marginal cirri, 2 on each side; 9 to 10 frontal cirri Genus *Euplotes , p.454 
3. Seven frontal, 5 anal, 3 right marginal, and 2 left marginal cirri Genus *Diophrys , p.456 
No frontal, 5 anal, 3 right, and 2 left marginal cirri Genus * Uronychia, p.457 
Genus EUPLOTES (Ehr. 1831) Stein '59. 
(Ehrenberg ’31, ’38; Stein ’59; Cl. & Lach. ’58; Quennerstedt '65, ’67, ’69; Btitschli ’88; Kent ’81; Gourret & 
Roeser ’88; Mobius ’88.) 
Small to medium-sized forms. Rigid in form, colorless, or green by chlorophyl. They are quite 
flat on the ventral surface but decidedly arched dorsally, and the contour is usually oval. The anterior 
end is broadly rounded to truncate; the posterior end is similarly rounded, or may be somewhat 
pointed. The mouth is placed centrally or near the left margin, and from it the right edge of the 
peristome forms a curved line to the left, which bends forward, thus making the greater part of the 
left edge the peristomial area. In front the peristome bends sharply to the right and extends as far as 
the right end of the adoral zone. Upon the frontal and median ventral surface are 9 to 10 great cirri 
( Bauckwimpern of Stein). Posteriorly five great anal cirri stretch out beyond the posterior body 
margin. In addition to these there are two smaller marginal cirri upon the left body edge, and two 
similar ones on the hinder part of the body. The dorsal surface is rarely smooth, but usually is 
marked by longitudinal ridges, and rows of dorsal bristles have been described. The single contractile 
vacuole lies on the right side in the region of the anal cirri, sometimes just above them, sometimes 
