sand dollar

plural sand dollars

1. Any echinoderm of the order Clypeasteroida, having a flat, disk-shaped body with the mouth in a mid-ventral position, and living in sand, on or near the surface.

   If you look carefully, a sand dollar is merely a sea urchin in flattened form.

   2001, Jennifer Hahn, Spirited Waters: Soloing South Through the Inside Passage, published 2009, page 135

   2 more examples

   In the sand dollars, the arrangement of the food grooves and consequently the lateral water vessels and their accessory tube feet is more complex (Phelan 1977).

   1987, John M. Lawrence, chapter I, in A Functional Biology of Echinoderms, page 75

   Adult echinoderms have a five-part body plan corresponding to the arms of a sea star or the design on the "shell" of a sand dollar.

   2000, Sandra Alters, chapter I, in Biology: Understanding Life, page 692

   Synonyms: clypeasteroid, sand cookie, sea cookie