Amoebida

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Amoebida (superclass Sarcodina, class Rhizopodea) An order of protozoa, lacking a test, in which each cell contains a single nucleus and is of indeterminate shape. The cells typically form lobopodia (rarely filopodia or anastomosing) which serve for locomotion and feeding. Most species are free-living in freshwater, moist-soil, or marine environments; a few are parasitic. There are several families, and many genera, one of which is the genus Amoeba. A. proteus, a popular subject for study in elementary biology courses, measures up to about 0.6 mm across, and is found in slow-moving or still, freshwater habitats.