Kent.

The body is variable in shape, but usually flattened and pointed
posteriorly. An anterior process is almost always present, and
below this the flagella are inserted in a minute depression. The
contractile vacuole is close to the base of the flagella. The
flagella are about the same size, the anterior one usually somewhat
longer. Common. Length 12 to 18 mu.

This species was seen by Peck '95 and described as a small
flagellate.

[Illustration: Fig. 14.--_Bodo caudatus_.]

Genus OXYRRHIS Duj.

(Kent '81; Buetschli '86; Klebs '92; Senn 1900.)

Medium-sized forms, somewhat oval in shape, with a rounded posterior
end. The anterior end is continued dorsally in a somewhat attenuate
pointed process. At the base of this process is a large cavity or
funnel, on the dorsal wall of which, or on a projection from this
wall, are two equal-size flagella. When at rest, the flagella are
directed backwards. The nucleus is central. In moving, the posterior
end is invariably in advance. This genus is exceptional among
Mastigophora in that division is transverse instead of longitudinal.

Oxyrrhis marina Duj. Fig. 15.

With the characters of the genus. Contractile vacuole not seen.
Length 28 to 40 mu.

[Illustration: Fig. 15.--_Oxyrrhis marina_.]

Genus ASTASIA Ehr.

Flagellates with one flagellum, a spindle-form body and a high
degree of plasticity, the contour constantly changing. A distinct,
usually striped cuticle is invariably present. "Eye-spots" are
absent. Fresh and salt water.

Astasia contorta Duj. Fig. 16.

_Astasia inflata_ Duj. '41.

The body is colorless, transparent, and flexible. It is largest in
the center, thence tapering at the two extremities. The surface of
the cuticle is obliquely striated, giving to the animal a distinctly
twisted appearance. The contractile vacuole is in the anterior
neck-like portion of the body. The flagellum is inserted in a
distinct oesophageal tube, into which the contractile vacuole
empties. This tube is continued into a deeper pharyngeal apparatus of
unknown function.

Common in decaying algae. Length 60 mu; greatest diameter 30 mu.

[Illustration: Fig. 16.--Two aspects of _Astasia contorta_.]

Genus ANISONEMA Buetschli

Flagellates with two flagella, of which one is directed forwards and
is concerned with the locomotion of the animal, while the other is
directed backwards and drags after the animal when in motion. Body
slightly compressed dors