the Ciliata and the Suctoria, are usually littoral in their habitat,
living upon the shore-dwelling, or attached, water plants and upon
the animals frequenting them. It is to be expected, therefore,
that in forms here considered there should be a preponderance of
Infusoria. Flagellated forms are also found in similar localities,
but on the Surface of the sea as well; hence the number described
in these pages is probably only a small proportion of the total
number of Mastigophora in this region. The Sarcodina, including the
Foraminifera and the Radiolaria, are typically deep-sea forms and
would not be represented by many types in the restricted locality
examined at Woods Hole. Two species, _Gromia lagenoides_ and
_Truncatulina lobatula_, alone represent the great order of
Foraminifera, while the still larger group of Radiolaria is not
represented at all.

The Protozoa described are distributed among the different orders as
follows:*


Class SARCODINA.
Subclass RHIZOPODA.
Order AMOEBIDA.
1. _Amoeba guttula_ Duj
2. _Amoeba_ sp.
3. _Trichosphærium sieboldi_ Schn.
Order RETICULARIIDA.
Suborder IMPERFORINA.
4. _Gromia lagenoides_ Gruber.
Suborder PERFORINA.
5. _Truncatulina lobatula_ Walker & Jacob.