SYNOPSIS.Of set‐era1 strains ofEiztarnochaisolated from human patients diagnosed to have mild. chronic amebiasis, two strains (AG and JA) Were found to have the ability to grow well at room temperature, in addition to growing at 37°C. Subsequent genetic analysis has shown these two strains to be very closely related to the well‐known “Laredo strain ofEntamoeba histolytica.” The implications of the marked differences from “true”E. histoliticaa