This collapsible sea urchin (Phormosoma species), brought up from 1,500 metres, does not have a hard skeleton but instead uses fluid pressure to keep its shape. When taken out of the water it collapses and the fluid leaks out, so it resembles a deflated basketball. The short tentacles have sacs at the tip which release poison on contact with another animal.
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This image has been provided courtesy of the NORFANZ partners – Australia’s National Oceans Office and CSIRO and New Zealand’s Ministry of Fisheries and NIWA. The use of this image does not imply the endorsement of the NORFANZ partners of the content of this entry.