Day 53: Pursuits of a vacant mind
Priya Ramani -
Wednesday, June 04, 2008 9:48 PM
Just one pursuit actually.
Today I went for a walk on the beach and encountered these flat bleached shells that looked like parts of a broken necklace swept ashore. They turned out to be sand dollars (Photo: My gift for my niece Tara).
Here´s what Wiki says:
Sand Dollars are in the Echinoid (Echinoderms) class of marine animals. When they are living, they are covered with a suit of moveable spines that encompass the entire shell. Like its close relative the sea urchin, the sand dollar has a set of five pores arranged in a petal pattern. The pores are used to move sea water into its internal water-vascular system, which allows the creature to move.
Sand dollars live beyond mean low water on top of or just beneath the surface of sandy or muddy areas. The spines on the somewhat flattened underside of the animal allow it to burrow or to slowly creep through the sand. Fine, hair-like cilia cover the tiny spines. Tubefeet or podia that line the food grooves, move food to the mouth opening which is in the center of the star shaped grooves on the underside of the animal called the oral surface.
The name "sand dollar" is a reference to their round flat shape, which is similar to a large coin. The term "sand dollar" can also refer to the test left when a sand dollar dies. By the time the test washes up on the beach, it is usually missing its velvety covering of minute spines and has a somewhat bleached appearance due to its exposure to the sun.