Page 36 - One Million Things: Animal Life - The Incredible Visual Guide

Familiar and star-shaped, starfish have five or more arms attached to a central disk. They are scavengers or predators that crawl over the sea bottom using their suckerlike tube feet. They feed by pushing their stomachs out through their mouths to surround food, digest it, and suck up the juices. A sea urchin’s globe-shaped body lacks arms but has a hard outer test or shell. Tube feet project through the test, which is armed with movable spines to deter enemies and aid movement. Sea urchins move slowly over rocks, grazing on algae Cl

STARFISH SEA URCHIN or eating small animals. SAND DOLLAR by many small spines. Their body shape helps them to burrow easily into

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FEATHER STAR Like their close relatives the sea lilies, plantlike feather stars are usually attached to the sea bottom by a stalk. Some, however, are free-swimming as adults. Feather stars feed by using their arms to transfer food particles from the surrounding water into their central, upward-facing mouth. SEA CUCUMBER Sea cucumbers have more flexible bodies than other echinoderms. They also have a front end, with a mouth, and a back end, with an anus. The mouth is surrounded by tentacles that filter small particles of food from the

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distinct heads. Instead, the body is divided into five equal parts
underside. The body is supported by an internal skeleton made
These distinctive animals are found only in the sea. Echinoderms,
arranged around a central disk, with the mouth usually on its
hydraulic system pumps water into and out of sausagelike
including starfish, sea urchins, and their relatives, have no
tube feet, each tipped with a sucker, that project from the
of chalky plates covered by spiny thin, skin. An internal

ECHINODERMS

body and are used for movement.

These small echinoderms are flattened and disk-shaped, with no arms but a ring of spines around their margin. Their structure is similar to other echinoderms, with a body arranged in five parts. They probably feed on bacteria and

SEA DAISY microscopic mollusks. 1

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