'Sphaeridium' definitions:

Definition of 'Sphaeridium'

From: GCIDE

Sphaeridium \Sphae*rid"i*um\, n.; pl. Sphaeridia. [NL., fr. Gr. ??? a sphere.] (Zool.) A peculiar sense organ found upon the exterior of most kinds of sea urchins, and consisting of an oval or sherical head surmounting a short pedicel. It is generally supposed to be an olfactory organ. [1913 Webster]