A Soft Coral

Found this strange looking object on the beach at Shell Bay on Christmas Day. It looked like a collection of pebbles stuck together but was spongy. Had some difficulty identifying it. At first I thought it might be a sponge or a sea squirt. Now I'm fairly certain that it is a soft coral, Alcyonium digitatum - colloquially known as Dead Man's Fingers.

The surface seems a bit like the skin of an orange in texture. Tiny holes can be seen and in the living organism white polyps extend from these holes withdrawing if disturbed. Each polyp bears eight small tentacles, which gives the colonies a feathery appearance. The pictures in the seashore guides that I have all showed the organism in situ with the polyps extended, which made the identification of the washed up specimen more difficult.

A section through one of the 'fingers'. Each tentacled polyp that make up the colony is housed in a common spongy mass that is given form by the inclusion of minute chalky or calcareous particles. When the polyps are extended the colony filter-feeds on plankton.

This rather gruesome looking picture shows the underside where it was attached to a rock or other solid structure. It was probably detached during the recent stormy weather.