The correct answer is D, Entamoeba coli.  In E. histolytica (and the morphologically undistinguishable E. dispar) and in E. hartmanni cysts, the chromatoid bodies are elongated with bluntly rounded ends.  The chromatoid bodies of Entamoeba coli are splinter-like with pointed ends.  As for the other amebas, E. polecki cysts have chromatoid bodies that are polymorphic.  Characteristic chromatoid bodies as seen in Entamoeba spp. are not present in cysts of Iodamoeba buetschlii and Endolimax nana.

Click here to open a new window with a table containing comparative morphological characteristics of ameba cysts.  Close the new window to return to this page.