sand dollar

any of various flat, disklike sea urchins, as Mellita testudinata or Echinarachnius parma, that live on sandy bottoms off the coasts of the U.S.
[1880-85, Amer.]

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Any echinoderm (order Clypeastroida, class Echinoidea) that has a coinlike, thin-edged body.

Five "petals" spread out from the center of the upper body. It burrows in sand, feeding on organic particles wafted to the mouth, located in the center of the body's underside. Small spines covering the body are used for digging and crawling. Tests (external skeletons) of the common sand dollar (Echinarachnius parma), which often wash up on beaches in North America and Japan, are 2–4 in. (5–10 cm) in diameter.

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      any of the invertebrate marine animals of the order Clypeastroida (class Echinoidea, phylum Echinodermata) that has a flat, disk-shaped body. They are close relatives of sea urchins and heart urchins. The sand dollar is particularly well adapted for burrowing in sandy substrates. Very small spines used for digging and crawling cover the entire surface of its body and are appressed backwards toward the posterior anus. The mouth is located in the centre of the body's underside. The upper surface exhibits pentaradiate symmetry, with a pattern of five “petals” spreading out from the centre. Some species found stranded on the shores of North America have five or six slots, or lunules, through the test (external skeleton). Most sand dollars measure from 5 to 10 cm (2 to 4 inches) in diameter. Species of comparable size occur in shallow coastal waters throughout the rest of the world, except in Europe and Antarctica.

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Universalium. 2010.

Look at other dictionaries:

  • Sand dollar — Temporal range: 56 –0 Ma …   Wikipedia

  • Sand dollar — Sand Sand, n. [AS. sand; akin to D. zand, G. sand, OHG. sant, Icel. sandr, Dan. & Sw. sand, Gr. ?.] 1. Fine particles of stone, esp. of siliceous stone, but not reduced to dust; comminuted stone in the form of loose grains, which are not coherent …   The Collaborative International Dictionary of English

  • Sand Dollar A3 — (Кралендейк,Бонэйр, Синт Эстатиус и Саба) Категория отеля: Адрес: Kaya Gob. N. Debro …   Каталог отелей

  • sand dollar — ☆ sand dollar n. any of an order (Clypeasteroida) of flat, round, disklike echinoid echinoderms that live on sandy ocean beds …   English World dictionary

  • sand dollar — sand′ dol lar n. ivt any flat, disklike echinoderm of the order Clypeasteroidea, of the same class as sea urchins, living on sandy bottoms • Etymology: 1880–85, amer …   From formal English to slang

  • sand dollar — noun An echinoderm, of the order Clypeastroida, that has a flat, disk shaped body with the mouth in a mid ventral position, and lives in sand, on or near the surface …   Wiktionary

  • sand dollar — noun a flattened sea urchin which lives partly buried in sand, feeding on detritus. [Order Clypeasteroida: many species.] …   English new terms dictionary

  • sand-dollar — /ˈsænd dɒlə/ (say sand doluh) noun any of various flat, disclike urchins, especially Echinarachnius parma, which live on sandy bottoms off the coast of North America …   Australian English dictionary

  • sand dollar — noun Date: 1884 any of numerous flat circular sea urchins (order Clypeasteroida) that live chiefly in shallow water on sandy bottoms …   New Collegiate Dictionary

  • sand dollar — noun flattened disklike sea urchins that live on sandy bottoms • Hypernyms: ↑sea urchin • Member Holonyms: ↑Exocycloida, ↑order Exocycloida * * * noun, pl ⋯ lars [count] US : the round, flat shell of a small sea animal; also : the small sea… …   Useful english dictionary

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