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sand bar

Keyhole sand dollar Echinodiscus sp. Order Clypeasteroida Keyhole sand dollars are sometimes seen on the north sand bar. Why do they have holes? Their common name comes from the intriguing holes in their bodies which are called lunules. Suggestions for the function of these slots range from helping the animal to burrow, right itself, find food or to prevent the waves from lifting it out of the sand. The last is the most widely accepted explanation. Keyhole food: Keyhole sand dollars eat detritus. These sand dollars have lots of tiny tube feet which are used to gather small organic particles found among the sand grains. They have teeth in their central mouth.		A living Keyhole sand dollar A dead Keyhole sand dollar

Underside
(Dead sand dollar)

Underside
(Living sand dollar)

Upper side
(Living sand dollar)

quick facts
Diameter about 10cm, sometimes seen

Classification:
Order Clypeasteroida
Class Echinoidea
Phylum Echinodermata

See also ...
Echinoderms in general
Sand dollars in general

Links
Echinodiscus and Cylpeasteroida from the Echinoid Directory on the London Natural History Museum website: a technical description of the family and order to which the Cake sand dollar belongs.

a companion website to the chek jawa guidebook website©ria tan 2003 www.wildsingapore.com

a companion website to the chek jawa guidebook
website©ria tan 2003 www.wildsingapore.com