Fig. 24.2.

Polychaetes. (A) Family Nereididae: Perinereis helleri with its pharynx everted showing paragnaths, an important diagnostic character for this family. Size: up to 4–5 cm in length. (Photo: H. Nguyen, lab of C. Glasby, Museum and Art Gallery Northern Territory, Darwin.) (B) Family Amphinomidae: Chloeia flava moving over the sediment. The chaetae easily break off and become embedded in fingers if the animal is picked up. Size: up to 100 mm in length (Photo: R. Steene). (C) Family Amphinomidae: Eurythoe spp. complex, ‘fire worm’. These worms are commonly found under boulders intertidally and shallow subtidally. The dark red bushy branchiae are present adjacent to the parapodia all along body. Size: up to 60–80 mm in length (Photo: K. Atkinson). (D) Family Amphinomidae: Pherecardia sp. crawling over the substrate in search of food. It uses its eversible muscular pharynx to feed on sponges, anemones, hydroids, and so on. (Photo: R. Steene). (E) Family Terebellidae: Reteterebella lirrf deeply embedded within the coral substratum with highly extensile feeding tentacles spread out over the surface of the reef collecting food particles and moving them along the tentacles to the mouth (Photo: P. Hutchings). (F) Family Serpulidae: Spirobranchus corniculatus-complex illustrating the diversity of colours on a single live colony of Porites. This species settles on a damaged polyp, secretes a calcareous tube and encourages the coral to grow around the worm (Photo: R. Steene); (G) Family Sabellidae: Megalomma interrupta, a colourful fan worm. Each radiole has numerous fine filaments along its length that are used to strain the water passing through the crown. Particles pass down the axis of each radiole to the mouth, where they are eaten, used for tube construction or rejected. The crown is 50–100 mm in diameter (Photo: A. Semenov). (H) Family Sabellidae: Sabellastarte sp. This worm is fully extended from its muddy tube. The tentacular crown 50–100 mm in diameter is used in filter feeding and for respiration. (Photo: R. Steene.) (I) Family Eunicidae: Marphysa spp. complex, commonly known as blood worms, common in seagrass and muddy habitats adjacent to reefs, up to 200 mm in length. (Photo: K. Atkinson.) (J) Family Eunicidae: Eunice aphroditois emerges at night from its burrow to feed, keeping its jaws open for passing prey such as crustaceans and drift algae that are then grabbed and drawn down into the buccal cavity. They are sensitive to vibration and can rapidly withdraw into their burrows. They are found on shallow coral reefs and may reach 1–2 m in length (Photo: R. Steene). (K) Family Phyllodocidae: Phyllodocid found in coral sediments, with expanded dorsal cirri all along its body. Size: 4–5 cm in length (Photo: K. Atkinson). (L) Family Phyllodocidae: Phyllodoce sp. Mass spawning of these worms coincides with coral spawning. These worms normally live under rubble and swim up into the water column to spawn at around 2100 h (Photo: P. Hutchings).