The sarcodinid parasites of concern are the amebae (spelled by some with an "o", e.g., "amoebae"). These organisms are characterized by their form of movement which involves the directional extension of the cell body by processes called pseudopodia; this movement is accomplished without cilia or undulipodia. The feeding stage is called a trophozoite which ingests particles by surrounding them with cytoplasm of an engulfing pseudopod. Some amebas have a cyst stage which is resistant to environmental extremes. Amoebae are found both as free-living forms and as parasitic forms in diverse hosts ranging from cockroaches to humans. Humans are host to several species of amoeba, but only one species, Entamoeba histolytica, is a serious pathogen of humans in which it causes large bowel disease and occasionally hepatic or other deep tissue abscesses. Cats do not appear to be typical hosts of this pathogenic ameba, even though they have been experimentally infected to study the pathogenic effects of this parasite. Cats have, however, on at least one occasion been reported to be infected with this parasite (Kessel, 1928)