'Spatangoidea' definitions:

Definition of 'Spatangoidea'

From: GCIDE

Spatangoidea \Spat`an*goi"de*a\, n. pl. [NL. See Spatangus, and -oid.] (Zool.) 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. [1913 Webster]