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
calcareous sponge
invertebrate
Also known as: Calcarea
calcareous sponge, any of a class (Calcarea) of sponges characterized by skeletons composed entirely of calcium carbonate spicules (needlelike structures). Calcareous sponges occur mainly on the rocky bottoms of the continental shelves in temperate, shallow waters; they are usually dull in colour. Most are small, seldom exceeding 15 cm (6 inches). A few fossil representatives are known from the Burgess Shale (a rock formation deposited about 505 million years ago) in British Columbia, Canada.
This article was most recently revised and updated by John P. Rafferty.
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.