Anatomia di un polipo corallino.
<a href="//commons.wikimedia.org/wiki/User:Ruthven" title="User:Ruthven">Ruthven</a>
Own work based on: <a href="//commons.wikimedia.org/wiki/File:Coral_polyp_de.svg" title="File:Coral polyp de.svg">Coral polyp de.svg</a> <i>by</i> <a href="//commons.wikimedia.org/wiki/User:MarkusZi" title="User:MarkusZi">MarkusZi</a>