Sea worms are encased in protective tubes, which are made
of mucus, sand, and bits of shell,. To eat, the worm extends a feathery bouquet of tentacles.
Tiny beating hairs on the tentacles cause water to flow through
the "feathers," where particles of drifting plants, animals and debris get trapped. The worm sorts its catch, rejecting
pieces too large to eat, saving pieces suitable for tube building, and eating the rest.
The feather dusters have a shadow reflex, which means
that the worm withdraws its tentacles in a fraction of a second any time an object passes nearby.
