A sea cradle from Sydney, Australia. Top: terminal valve from dorsal, bottom: animal from dorsal.
W.H.Baily
<i>Proceedings of the Zoological Society of London</i> (<a rel="nofollow" class="external text" href="https://archive.org/details/proceedingsofgen51zool">vol. 1852</a>, <a rel="nofollow" class="external text" href="https://archive.org/stream/proceedingsofgen51zool#page/n496/mode/1up">plate Mollusca XVI</a>)