• Popularly known as the Paddle worm.

• Marine, tube dwelling annelid. Lives in U- shaped tubes, formed of sand and pebbles, glued together with mucus.

• Body has 3 regions – Anterior, Middle and Posterior.

• Anterior is ten – segmented, Middle region is 5 segmented, posterior region is many segmented.

• Anterior region has nine pairs of parapodia.

• Anterior region bears a dorsal food groove.

• Chaetopterus is noted for Bioluminescence and great regenerative powers. It can emit Bluish-green light.