Photo of <i><a href="//commons.wikimedia.org/wiki/Scaphander_lignarius" title="Scaphander lignarius">Scaphander lignarius</a></i> (Linné, 1758) (Cephalaspidea) – Northern Sea.
Heike Wägele &amp; Annette Klussmann-Kolb
CC BY 2.0
<p>cropped from Figure 1 <a rel="nofollow" class="external free" href="http://www.frontiersinzoology.com/content/2/1/3/figure/F1">http://www.frontiersinzoology.com/content/2/1/3/figure/F1</a> <a rel="nofollow" class="external free" href="http://www.frontiersinzoology.com/content/download/figures/1742-9994-2-3-1.JPEG">http://www.frontiersinzoology.com/content/download/figures/1742-9994-2-3-1.JPEG</a> from:<br></p>
Heike Wägele &amp; Annette Klussmann-Kolb: <a rel="nofollow" class="external text" href="http://www.frontiersinzoology.com/content/2/1/3">Opisthobranchia (Mollusca, Gastropoda) – more than just slimy slugs. Shell reduction and its implications on defence and foraging</a>. - Frontiers in Zoology 2005, 2:3. doi:10.1186/1742-9994-2-3