A shell of <i>Drupa morum</i>. These small snails live in shallow waters on corals.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/8796022@N07">Roberto Verzo</a>
CC BY 2.0
originally posted to <b><a href="//commons.wikimedia.org/wiki/Flickr" class="mw-redirect" title="Flickr">Flickr</a></b> as <a rel="nofollow" class="external text" href="https://www.flickr.com/photos/8796022@N07/3263347958">Drupa morum morum Röding, 1798</a>