Dientamoeba fragilis n. g., n. sp., a new Intestinal Amoeba from Man

It is now becoming generally recognized that there are three different amoebae which may be present in the human bowel—the harmless Entamoeba coli (Lösch) Schaudinn and “ Entamoeba ” nana Wenyon and O'Connor, and the pathogenic E. histolytica Schaudinn. We have discussed these three species in an earlier paper (1917), and there noted their chief distinctive characters. In the present paper we shall describe a fourth and much less common species which we have recently encountered. It differs in some respects so conspicuously from the others that it appears to us necessary to place it not only in a new species, but even in a new genus. We propose therefore the new name Dientamoeb fragilis for our amoeba, but we can discuss the question of nomenclature most conveniently after we have described the organism itself. This, therefore, we shall now do.