Spatangoidea
Spat`an*goi"de*a\, n. pl. [NL. See
Spatangus, and
-oid.] (Zo["o]l.) 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.
