Adding us as a Preferred Source tells Google you trust our content, so our articles show up more often in your Google Search, Discover feed, and AI Overviews.
verifiedCite
While every effort has been made to follow citation style rules, there may be some discrepancies.
Please refer to the appropriate style manual or other sources if you have any questions.
Select Citation Style
heart urchin
echinoderm
Also known as: Spatangoidea
heart urchin, any echinoid marine invertebrate of the order Spatangoidea (phylum Echinodermata), in which the body is usually oval or heart-shaped. The test (internal skeleton) is rather fragile with four porous spaces, or petaloids. The body is covered with fine, usually short spines.
Heart urchins live in burrows lined with mucus. Long tentacles (modified tube feet) reach out over the sand to pick up small particles of food; other tube feet have respiratory and sensory (not locomotive) functions. Movement is carried out by means of the spines.
The common heart urchin (Echinocardium cordatum) occurs in all oceans. Spatangus purpureus is common on the coasts of western Europe, the Mediterranean, and western Africa.
Britannica Quiz
Deadliest Animals Quiz
Discover how ordinary objects work, and expand your understanding of the familiar.
" height="20" alt="HEW Logo">
By clicking "Sign Up", you consent to the Britannica Privacy Policy and Terms of Use.