The Amoebidae are a family of Amoebozoa

Amoebozoa

The Amoebozoa are a major group of amoeboid protozoa, including the majority that move by means ofinternal cytoplasmic flow. Their pseudopodia are characteristically blunt and finger-like,...

, including naked amoebae that produce multiple pseudopodia of indeterminate length. These are roughly cylindrical with granular endoplasm and no subpseudopodia, as found in other members of the class Tubulinea

Tubulinea

The Tubulinea are a major grouping of Amoebozoa, including most of the larger and more familiar amoebae likeAmoeba, Arcella, and Difflugia.-Characteristics:During locomotion most Tubulinea have a roughly cylindrical...

. During locomotion one pseudopod typically becomes dominant and the others are retracted as the body flows into it. In some cases the cell moves by "walking", with relatively permanent pseudopodia serving as limbs.

The most important genera are Amoeba

Amoeba

Amoeba is a genus of Protozoa.History=The amoeba was first discovered by August Johann Rösel von Rosenhof in 1757. Early naturalists referred to Amoeba as the Proteus animalcule after the Greek god Proteus, who could change his shape...

and Chaos

Chaos (amoeba)

Chaos is a genus of giant amoebae. The largest and best known species, Chaos carolinensis, can reach lengths of 5mm, although most specimens fall between 1 and 3 mm....

, which are set apart from the others by longitudinal ridges.

Some sources include Dictyostelium discoideum

Dictyostelium discoideum

Dictyostelium discoideum is a species of soil-living amoeba belonging to the phylum Mycetozoa. D. discoideum, commonly referred to as slime mold, is a eukaryote that transitions from a collection of unicellular amoebae into a multicellular slug and then into a fruiting body within its lifetime. D...

in this group.