The Cymatium Röding, 1798 is a small-to large-sized marine gastropod genus belonging to family Ranellidae Gray, 1854 and it is widely distributed in the tropical seas. Ten species have been reported hitherto under the genus Cymatium from the Andaman and Nicobar Islands (Subba Rao and Dey, 2000). Three species, namely Cymatium (Ranularia) tripum (Gmelin, 1791), Cymatium (Septa) hepaticum (Röding, 1798) and Cymatium (Monoplex) pilearis (Linnaeus, 1758) were collected by hand picking and skin diving from Andaman Islands. This is the first study to report the occurrence of these three species from Andaman and Nicobar Islands, providing a detailed description of the species with the illustrations for the shell morphology.

Ranellidae, Cymatium, Ranularia tripum, Septa hepaticum, Monoplex pilearis, Andaman.