2. Body striped; not plastic; Genus *_Anisonema_
posterior flagellum longer
than the other

3. Body striped; not plastic; Genus _Entosiphon_
with rod-like organ in pharynx

* Presence at Woods Hole indicated by asterisk.


Genus MASTIGAMOEBA F. E. Schultze '75.

(Kent '81; Bütschli '86; Klebs '92; Senn 1900.)

In general the form is oval and either regular in outline or
irregular through the presence of many pseudopodia. One flagellum
usually quite large and distinct. Differentiation of ectoplasm and
endoplasm distinct or wanting. One to several contractile vacuoles.
The pseudopodia are occasionally withdrawn, and the flagellum is the
sole means of locomotion. In some cases the flagellum turns into a
pseudopodium, and, conversely, the pseudopodium at one end may become
a flagellum (see below). In some rare cases the ectoplasm secretes a
gelatinous mantle. Reproduction not observed.

Fresh and salt water.


Mastigamoeba simplex, n. sp. Fig. 7.

A very small form, first seen in the flagellated stage, aroused my