side the atoll. They have practically all the colors of the rainbow plus many darker shades. Living in clear waters of warm temperatures, they reproduce rapidly, assuming a wide variety of shapes, ranging from the red pipe-organ type to the antler-like forms. The many small tentacles which extend from the coral colonies are constantly in motion, resembling wind-rippled grain fields, as they sweep the water for tiny food organisms. Portuguese men-o-war and jellyfish, commonly called sea nettles by ocean bathers, are not abundant enough to become a nuisance, but they are seen occasionally.
The next animal group well represented on the reef is the "echinoderms" or spiny-skinned animals, The following are most commonly seen at Ulithi: sea stars, brittlestars, sea urchins, heart urchins, and sea cucumbers. These animals are armored with tough, spine-covered external skeletons and usually are found under rocks and boulders or in crevices where they lodge themselves securely. They feed on crustaceans, molluscs, and other small animal life which they are able to capture. Their stomachs can be everted to envelop the prey, and the strong digestive juices quickly break down the soft flesh and organs of the captive. The shells and skeletons are then ejected from the stomach. The power of regeneration or regrowth of body parts is a well-known habit in this group. The newly-formed member is usually somewhat smaller than the original organ.
Crustaceans are common in water and on land. Hermit crabs may be seen almost anywhere on the reef in shallow water, but they appear to prefer areas of loose rock which affords them protection, There they select vacant shells of molluscs into which they retreat, the shell shielding their soft abdomens. As they grow, they change accordingly to larger shells. Often the shell is so heavy it can be moved with nothing less than great strain.
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