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
Protozoa. The nucleus is spherical and contains one or two large
karyosomes. The protoplasm is densely and evenly granular, without
regional differentiation. I have never observed an external layer of
foreign particles, such as Gruber described in the original species.

Length of shell 245 mu; largest diameter 125 mu.

[Illustration: Fig. 4.--_Gromia lagenoides_.]

Genus TRUNCATULINA D'Orbigny.

A group of extremely variable foraminifera in which the shell is
rotaline; i. e., involute on the lower side and revolute on the upper
(Brady). The shell is calcareous and coarsely porous in older forms.
The characters are very inconstant, and Brady gives up the attempt to
distinguish the group by precise and constant characters.

Truncatulina lobatula Walker & Jacob.

Synonyms: See Brady '84 for a long list.

"It is impossible to define by any precise characters the
morphological range of the present species. Its variations are
infinite." (Brady, p. 660.)

This very common form, which occurs in all latitudes, was found
frequently among the algae at Woods Hole. Its characters are so
difficult to define that for the present I shall limit my record to
this brief notice. Size of shell 230 mu by 270 mu.

Genus ACTINOPHRYS Ehr.

The body is spherical and differentiated into granular endoplasm and
vacuolated ectoplasm, but the zones are not definitely separated.
There is one central nucleus and usually one contractile vacuole. The
pseudopodia have axial filaments that can be traced to the periphery
of the nucleus. Fresh and salt water.

Actinophrys sol Ehr., variety. Fig. 5.

Synonyms: See Schaudinn '95.

The diameter is about 50 mu; the vacuolated ectoplasm passes gradually
into the granular endoplasm. This is the characterization given _A.
sol_ by Schaudinn, and it applies perfectly to th