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Eccentric sand dollar

Dendraster excentricus

Description:

The Eccentric sand dollar is basically a flattened sea urchin that burrows in the sand. The average size is 76 mm wide with a dome shape. They are colored gray, brown, black or shades of purple. The underside is covered with tiny spines (pics 1 and 2) and like most sand dollars, are filter feeders, and they use the small spines that cover their bodies to snag crustacean larva, plankton, and other tiny prey. The food is slowly passed from spine to spine until it reaches mouth at the middle of the bottom side of the body. The spines are also used for locomotion, along with a series of tube feet, so called because they are operated by a hydraulic system controlled by the main body. When eccentric sand dollars move, they lay flat on the bottom with the mouth side facing down. The tube feet are also utilized for obtaining oxygen from the environment.

Habitat:

Spotted at the Dash Point State Park beach at low tide. Range: west coast of North America, from Alaska to Baja California.

Notes:

This was a large colony of sand dollars with thousands of members seen in pic 6.

No species ID suggestions

4 Comments

Brian38
Brian38 a week ago

Thank you Neil, Sukanya and Leuba for your kind words.

Leuba Ridgway
Leuba Ridgway a week ago

Wonderful close-up shots of both sides and nice to see the spines intact. Thanks for sharing.

SukanyaDatta
SukanyaDatta a week ago

Love the name.
.

Neil Ross
Neil Ross a week ago

I've never heard of this species before. Amazing spotting, Brian. Great info and pics too.

Federal Way, Washington, USA

Lat: 47.32, Long: -122.41

Spotted on Mar 9, 2019
Submitted on Mar 10, 2019

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Pacific Sand Dollar Eccentric sand dollar Eccentric Sand Dollar Sand dollar

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