This test was standing up next to a rock on the beach. When I picked it up to take a photo I was pleased it was not broken. The skeleton is bleached white by the sunlight according to Wikipedia.
Steinbeck and Ricketts called this E. californica.
The very fine beach near the southern end of Isla Magdalena is called, and aptly, 'sand dollar beach'; featuring a million-dollar strand.
Found broken piece on the beach. There was a tremendous weather change all day Friday w strong wind 40 mph al day and day. Waves were crashing. Many broken shells are on then each this am
aka Pacific Sand Dollar. Found a perfect, whole sand dollar!
Dive site Barracuda Reef; max depth 72 feet.
Is it just the force of the wave action or are all the intact sand dollars scooped up by beach combers to sell in the tourist shops?
For more information on the habitat, vegetation, and weather of the area where I made this observation, please see the journal entry for April 28, 2012 here on iNaturalist. This was an amazing thing for me to get to see. I had never once before seen a live sand dollar, only the dead ones that litter the beaches as sea shells to collect. What looks like mud covering them is actually a fine layer of spiny, tube-like feet that is used in feeding. I was extremely interested to learn that these are just burrowing sea urchins. They lived in the tide pools along the beach alongside hermit crabs, other smaller crabs, barnacles, and mussels. Each one was about 2.5 inches across.
Sand dollars (order Clypeasteroida) are flat, round marine animals related to sea urchins, sea stars, and other echinoderms. The most common sand dollar, Echinarachnius parma, is widespread in circumpolar ocean waters of the Northern Hemisphere, from the intertidal zone to considerable depths.