Cyst of a dinoflagellate <i>Peridinium ovatum</i>.
<ul><li>Johann Friedrich Oltmanns (1860–1945) – original work</li>
<li><a href="//commons.wikimedia.org/wiki/User:Smith609" title="User:Smith609">Smith609</a> – derivate work</li></ul>
<cite class="book" style="font-style:normal">Oltmanns, Freidrich (1904)      <i> Morphologie und biologie der Algen</i>, 1, <a href="https://en.wikipedia.org/wiki/en:Jena" class="extiw" title="w:en:Jena"><span title="city in Thuringia, Germany">Jena</span></a>:  Gustav Fischer  <small></small></cite>