Tubeworm (Lamellibrachia sp.) protruding from its chitinous tube. The red feather-like structures are the gills used for respiration. The white fleshy structure (centre) is called an obturaculum and protects the opening of the tube when the worm withdraws into it. This genus relies on symbiotic bacteria to metabolise sulphites as a source of nutrients. These sulphites are expelled from deep sea hydrothermal vents.