Aplysia \A*plys"i*a\, n. [Gr. ? a dirty sponge, fr. ? unwashed; 'a priv. + ? to wash.]

(Zo["o]l.) A genus of marine mollusks of the order Tectibranchiata; the sea hare. Some of the species when disturbed throw out a deep purple liquor, which colors the water to some distance. See Illust. in Appendix.

Source: Webster's Revised Unabridged Dictionary (1913)