Neomphalus fretterae has a moderately large protoconch with reticulate sculpture over the proximal half of the shell. The distal half is smooth, with the outer edge flaring out above the aperture. The aperture is sinuous and there is a wide rim, tapering toward the inner edge, which is visible under the light microscope.
Cyathermia naticoides has a moderately large protoconch. The posterior is covered by coarse reticulate sculpture which gives the appearance of bubbles under the light microscope. The anterior portion is smooth. The aperture is slightly sinuous and there is a medium-width rim.
Cyathermia naticoides has a moderately large protoconch. The posterior is covered by coarse reticulate sculpture which gives the appearance of bubbles under the light microscope. The anterior portion is smooth. The aperture is slightly sinuous and there is a medium-width rim.
