Umbonium omphalotropis (A. Adams, 1863) Ethalia omphalotropis is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails.

[1] The small, semi-transparent shell has an ovate-discoidal shape.

The 3½ convex whorls increase rapidly in size with deeply marked sutures.

This species has a peculiar sharp keel surrounding the umbilicus.

[2] This marine species occurs off Japan.