Fig. 3.

Morphology of the cytostome and the phagotroph. This figure contains three 100-nm-thick TEM sections showing a portion of two trophozoites living within a red blood cell. A large hemoglobin-containing invagination is shown in A, and the opening of the invagination can be seen. This is morphologically distinct from the electron-dense, constricted openings of cytostomes shown in B and C. Large invaginations are distinguished from phagotrophic vesicles by the fact that phagotrophs are closed off from the red blood cell cytosol. (Scale bar, 1 μm.)