(n.pl.) An order of irregular sea urchins, usually having a more or less heart-shaped shell with four or five petal-like ambulacra above. The mouth is edentulous and situated anteriorly, on the under side.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). Spatangoidea. Retrieved September 21, 2026, from http://smartdefine.org/spatangoidea/definitions/2064481 |
| Chicago | Webster's. 2011. "Spatangoidea" http://smartdefine.org/spatangoidea/definitions/2064481 (accessed September 21, 2026). |
| Harvard | Webster's 2011, Spatangoidea, Smart Define, viewed 21 September, 2026, <http://smartdefine.org/spatangoidea/definitions/2064481>. |
| MLA | Webster's. "Spatangoidea" 28 May 2011. Web. 21 September 2026. <http://smartdefine.org/spatangoidea/definitions/2064481> |