Amoebae - Protozoan
Amoebae may be naked or enclosed in tests or shells. The marine, freshwater and parasitic naked amoebae have large commonly tubular lobopodia or fine strap like filopodia that are used for locomotion and feeding. The shelled amoebae are found in the sea, freshwater and soil. They are covered by a shell made up of secreted organic material or foreign mineral matter cemented together. A large aperture in the shell permits protrusion of lobopodia or filopodia.
Figure: Entamoeba coli a common dweller in the human gut
A number of commensal and parasitic amoebae inhabit the gut of different animals and humans. Entamoeba coli a commensal in human gut feeds on bacteria and intestinal debris while E.histolytica a parasite causes amoebic dysentery.