Many marine critters and plants literally live on one another.
I have often seen algae attached to the stems of wireweeds (Amphibolis spp.) I have also seen sea tulips and lace corals attached to seagrasses.
Today I found a special pair of such "live-on" partners - a bunch of dead goose barnacles which were washed ashore together with their host, a sea tulip.
The pink arrows point at the sea tulip. The blue arrows point at the goose barnacles.
I am not hundred percent sure that they were goose barnacles because their colours looked different from the ones I have seen. But I think their stalks (yellow arrows) are unmistakable.
Anyway, if they were goose barnacles, I wonder what happened to the shells? Can their shells just change color when they die?
UPDATE (22 August 09): Thanks to Diana Jones of the Western Australia Museum for identifying the animal to be goose barnacle Smilium peronii. See a more recent post about this goose barnacle here.