colony of honeycomb worms (Sabellaria alveolata). Honeycomb worms are marine annelids (segmented worms), also known as bristleworms, that live in tubes built from sand and shell fragments on exposed coasts. They often live in large colonies whose tubes form honeycomb 'reefs', which can measure several metres across and a metre deep. When submerged by the tide, the worms stick out their tentacled heads to catch food particles suspended in the water.