The individuals are small and provided with a long unbranched, or terminal, simply split stalk.  The individuals are single or colonial.  The Woods Hole form measured 22 mu over all; the body was 5 mu, the collar 3 mu, and the stalk 14 mu.  No colonies were seen, and only a few individuals upon red algae.

[Illustration:  Fig. 12.—­Codonosiga botrytis.]

Genus BODO (Ehr.) Stein.

(Stein ’59, Buetschli ’83; Klebs ’92; Senn 1900.)

The body is naked, usually amoeboid in its changes, and provided with two flagella, one of which is usually trailed along under and behind the animal.  The anterior end is usually pointed, with the flagella arising from a minute depression; the posterior end is rounded.  Specific characters very difficult to analyze.  Fresh and salt water.

Bodo globosus Stein.  Fig. 13.

The body during movement is globular or ovoid, without any anterior process.  The trailing flagellum is invariably much longer than the vibratory one.  The contractile vacuole lies in the anterior half of the body.  Solid food particles are taken in near base of flagella.

Length of body 9 to 12 mu; diameter 8 to 11 mu.  Common.

[Illustration:  Fig. 13.—­Bodo globosus.]

Bodo caudatus (Duj.) Stein.  Fig. 14.

Synonyms:  Amphimonas caudatus Duj.; Diptomastix caudata 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.