This <i><a href="https://en.wikipedia.org/wiki/Glaucus_atlanticus" class="extiw" title="w:Glaucus atlanticus">Glaucus atlanticus</a></i> was washed up on Surfers Paradise Beach in Queensland Australia. It is about 35 mm in length. The species swims upside-down and is accordingly countershaded for that position.
<ul><li><a href="//commons.wikimedia.org/wiki/File:Glaucus_atlanticus_1.jpg" title="File:Glaucus atlanticus 1.jpg">Glaucus_atlanticus_1.jpg</a>: <a rel="nofollow" class="external text" href="https://www.flickr.com/people/tjt195/">Taro Taylor</a> from Sydney, Australia</li>
<li>derivative work: <a href="//commons.wikimedia.org/wiki/User:Dapete" title="User:Dapete"><small>da</small>pete</a></li></ul>
CC BY 2.0
<a href="//commons.wikimedia.org/wiki/File:Glaucus_atlanticus_1.jpg" title="File:Glaucus atlanticus 1.jpg">Glaucus_atlanticus_1.jpg</a>