Steromphala umbilicalis, common name the flat top shell, is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails.

The shell is more depressed than Gibbula cineraria, and (although the base is flatter) never inclined to a pyramidal form.

The coloring is different; both have a similar kind of marking, but in the present species the longitudinal rays or streaks are red, besides being broader and not half so many as in the other species.

Just within the outer lip are two borders, one of yellow, the other of green variegated by red spots.

[2] This marine species occurs in European waters and in the Mediterranean Sea off Morocco.