(Dujardin 1835; M. Schultze '62; F. E. Schultze '74; Leidy '77;
Bütschli '83; Gruber '84.)

The form is ovoid or globular, and the body is covered by a tightly
fitting, plastic, chitin shell, which, in turn, is covered by a fine
layer of protoplasm. The flexibility of the shell makes the form
variable as in the amoeboid types. The thickness of the shell is
quite variable. The pseudopodial opening is single and terminal. The
pseudopodia are very fine, reticulate, granular, and sharply pointed,
and form a loose network outside of the shell opening. Nucleus single
or multiple. Contractile vacuole is usually absent. Fresh and salt
water.


Gromia lagenoides Gruber '84. Fig. 4.

This species is not uncommon about Woods Hole, where it is found upon
the branches of various types of algæ. The body is pyriform, with the
shell opening at the larger end. The chitinous shell is hyaline and
plastic to a slight extent, so that the body is capable of some
change in shape. The shell is thin and turned inwards at the
mouth-opening, forming a tube (seen in optical section in fig. 4)
through which the protoplasm passes to the outside. The walls of this
tube are thicker than the rest of the shell, and in optical section
the effect is that of two hyaline bars extending into the body
protoplasm. A thin layer of protoplasm surrounds the shell and
fine, branching, pseudopodia are given off in every direction. The
protoplasm becomes massed outside of the mouth-opening and from here
a dense network of pseudopodia forms a trap for diatoms and smaller