Echiura
. Spoonworm, common name for any of a small phylum of unsegmented worms with an internal body cavity and characterized by a stout body, or trunk, and a long flexible, spoon-shaped proboscis, or feeding organ. They are found on the ocean bottom from the shallow intertidal zone to depths of 10,000 m (32,808 ft.) Mature spoonworms, also called echiurans, are sedentary bottom feeders that burrow in mud, sand, or debris. A few live in rock crevices or enclosures such as abandoned sand dollar shells. Most spoonworms are dull in color, but a few are green, red, or transparent. With the proboscis retracted, they range in length from 1 to 20 cm (0.4 to 7.9 in). In most species, the trunk of the spoonworm lies buried in the muck or debris on the ocean bottom while the proboscis extends outward to grope for food. The touch- and taste-sensitive proboscis is flexible and may extend up to 2 m (6.56 ft). It has a groove lined with cilia (tiny hairs) along its length. Glands on the proboscis secrete