Sea squirts: Urochordata related to amphioxus and cephalochordata

Diagram by Woods Hole Oceanographic Institution Hole

Filter feeding in annelids: sabellid worms

Arenicola : lugwormPolychaete Annelida

• Tail toward head shaft• Ingests sand rich in micro-

organisms and plankton left by receding tide

• Every 40 min castings of sand• Tide in: stream of water driven

through burrow tail to head direction current gas exchange sweeps away carbon dioxide and nitrogen; body swellings

Commatulid grasping coral head on reef

Commatulidae: feather starspodia originate as filter feeding devices

Swimming in commatulids

Mole crab

Whale shark

Blue whale; baleen

krill