at the extremities of the body. Color, yellow with chromatophores.
Length 285µ; width 23µ.

Both of these species are common in the tow and in the algæ at the
edge of the wharf. Both of them are mentioned by Peck in '93 and '95.


[Illustration: Fig. 26.--_Ceratium fusus_.]


Genus AMPHIDINIUM Clap. & Lach.

The body is ovoid to globular and usually much flattened
dorso-ventrally. The anterior portion is very much reduced and is
somewhat head-like or cap-like. The longitudinal furrow extends
through the entire posterior body length and is apparently capable
of widening and narrowing. It is probably naked (see here Klebs,
Pouchet, Bütschli), although Stein maintained that there is a
delicate cuticle-like shell. Chromatophores of brown or green colors
present and usually grouped radially about a central amylum granule.
The nucleus is posterior.

Fresh and salt water.


Amphidinium operculatum Clap. & Lach. Fig. 27.

The body is oval and flattened. The transverse furrow is at the
extremity (posterior) of the body and the small portion, which is
thus apparently cut off, is the cap-like or operculum-like structure