The shell is ovate, rounded and swollen posteriorly. The anterior
border of both shells is slightly indented. The shell is quite thick.
The animal moves through the water very slowly. Dark brown in color.
Length 48µ; width 44µ.


[Illustration: Fig. 18.--_Exuviælla lima_.]


Exuviaella marina Cienkowsky. Fig. 19.

A smaller form than the preceding, more elliptical in outline, with
a thinner shell and with large granules throughout the endoplasm.
The nucleus is spherical and subcentral in position and possesses a
distinct central granule. This may be a small variety of _E. lima_.


[Illustration: Fig. 19.--_Exuviælla marina_.]


Genus GYMNODINIUM Stein '78.

(Bergh '81; Kent '81; Pouchet '83, '85; Entz '84; Schütt '95.)

The general structure of these forms is similar to that of
_Glenodinium_; the most striking and positive difference is the
absence of a shell. The animals are, as a rule, spherical, yet they
may be pointed at the two ends or at one of them. They are also
frequently flattened dorso-ventrally. The transverse furrow may
be either circular and straight around the body or may describe a