peristome edge, or it may cross over to the right anterior edge.

1. The anterior half of the body Genus _Balantidium_
tapers to nearly a point in front;
the peristome is narrowest at the
apex; the mouth is the entire
peristome base.

2. The anterior end does not taper; Genus *_Condylostoma_
the peristome is widest at the end
of the body; the mouth is clearly
defined.

* Presence at Woods Hole indicated by asterisk.


Genus CONDYLOSTOMA (KONDYLOSTOMA Bory de St. Vincent 1824) Dujardin
'41

(Dujardin '41; Claparède & Lachmann '58; Stein '59, '67; Cohn '66;
Quennerstedt '67; Wrzesniowski '70; Bütschli '76, '88; Kent '81;
Maupas '83; Shevyakov '96.)

Colorless and more or less flexible animals of medium size. The
general form is elongate and cylindrical or somewhat smaller
anteriorly. The posterior end is broadly rounded, the anterior end
somewhat truncate and oblique. The peristome is broad and triangular,
the base of the triangle being the entire anterior end of the body.
The entire length of the peristome is one-fourth or less of the body
length. The mouth is large and placed at the apex of the peristomial