trumpet worm tube

 

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This is the tube of a trumpet worm (most likely Pectinaria gouldii), also called the ice cream cone worm. It lives in the intertidal and shallow zones of the Gulf. The tube is made of sand grains. The walls of the tube are one grain thick. The tube is open at both ends, is very fragile and can get up to 7.5 cm (3 in) long. The worm orients itself vertically in the substrate with its head down at the wider end. The narrower end sticks slightly above the sediment. Tubes are sometimes termed "sand castles".