Sphaeridium
Pronunciation : Sph?*rid"i*um
Part of Speech : n.;
Etymology : [NL., fr. Gr. (Zo?l.)
Definition : Defn: 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.
pl. Sph?ridia.
Source : Webster's Unabridged Dictionary, 1913