Umbonella sismondae
# Umbonella sismondae

Umbonella sismondae is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails.

## Description

The height of the shell attains 4 mm, its diameter also 4 mm. The small, imperforate, greenish shell has a conoid shape. It contains minute, transverse striae. The apex is obtuse. The 41⁄2 whorls increase slowly in size. They are slightly convex and have a distinct suture. The body whorl takes up half of the total length. Its base is angulated and shows on its lower parts four concentric ribs. The oblique aperture is subcircular.

## Distribution

This species occurs in the Red Sea on coral reefs.

