A minute, almost quiescent, form which changes its contour very
slowly. The membrane is cap-like and extends over the dome-shaped
body, fitting the latter closely. The endoplasm is granular and
contains foreign food-bodies. Nucleus single, spherical, and
centrally located. Pseudopodia short and finger-form, emerging from
the edge of the mantle-opening and swaying slowly from side to side
or quiescent. The most characteristic feature is the presence of a
broad, creeping sole, membranous in nature and hyaline in appearance.
This membrane is the only evidence of ectoplasm, and it frequently
shows folds and wrinkles, while its contour slowly changes with
movements of body. The pseudopodia emerge from the body between this
membrane and the shell margin. Contractile vacuole absent. Length
42µ, width 35µ. In decomposing seaweeds, etc.

Only one specimen of this interesting form was seen, and I hesitate
somewhat in placing it on such a meager basis. It is so peculiar,
however, that attention should be called to it in the hope of getting
further light upon its structure and mode of life. Its membranous
disk recalls the genus _Plakopus_; its mononucleate condition, its
membranous disk, and the short, sometimes branched, pseudopodia
make it difficult to identify with any phase in the life-history of
_Trichosphærium_. I shall leave it here provisionally, with the hope
that it may be found more abundantly another time.


[Illustration: Fig. 3.--_Trichosphærium sieboldi_]


Genus GROMIA Dujardin '35.