wn, and the flagellum is the
sole means of locomotion. In some cases the flagellum turns into a
pseudopodium, and, conversely, the pseudopodium at one end may become
a flagellum (see below). In some rare cases the ectoplasm secretes a
gelatinous mantle. Reproduction not observed.

Fresh and salt water.

Mastigamoeba simplex, n. sp. Fig. 7.

A very small form, first seen in the flagellated stage, aroused my
interest by reason of the fact that its flagellum lost its regular
outline and became amoeboid, turning to a pseudopodium, while at the
same time other pseudopodia were protruded from different parts of
the periphery. In this condition ectoplasm and endoplasm could be
made out with the clearest definition. After the pseudopodia were
well formed, the body became flat and closely attached to the glass
slide. In a short time one of the pseudopodia became longer than the
rest; the body became more swollen; the pseudopodia were gradually
drawn in, with the exception of the more elongate one; this became
active in movement and finer in diameter, until ultimately it formed
a single flagellum at the anterior of a small monadiform flagellate.
The process was repeated two or three times under my observation,
so that I am convinced that it was not a developmental form of
some rhizopod. Several of them were seen at different times during
the summer, and they were always of the same size and form in
the flagellated or amoeboid condition. I did not make out their
reproduction, and I shall not be satisfied that this is a good
species until their life history is known.

In decaying algae. Length 10 mu.

[Illustration: Fig. 7.--_Mastigamoeba simplex_.]

Genus CODONOECA James Clark '66.

(Kent '81.)

Small forms inclosed in cup or "house" of ovoid or goblet shape,
colorless and probably gelatinous (chitin?) in texture, and borne
upon a stalk. The monad does not completely fill the test.
Contractile vacuole single, posterior.

Codonoeca gracilis, n. sp. Fig. 8.

The cup is urn-shaped with a well-defined neck or collar borne upon a
shoulder-like end of the body. It is hyaline, colorless, and carried
upon a stalk equal in length to the cup or shorter than this. The
animal does not fill the cup, nor is it attached by a filament to
the latter. There is a single flagellum. The nucleus is minute and
lateral in position; the contractile vacuole is in the posterior end
of the body. Total length of cup and stalk 21 mu; of