nAplysia(Zoöl) 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.
Century Dictionary and Cyclopedia
naplysiaA genus of gastropodous mollusks, the sea-hares, having an oval oblong form with four tentacles, and somewhat resembling slugs. Its numerous species are remarkable for the function of secreting a fluid of violet color (due to the presence of iodine), which they discharge when molested. One of the best known is A. depilans, the depilatory seahare, so called because it was supposed that the fluid it discharged was capable of removing hair or preventing its growth. Also written Laplysia, by an original mistake (Linnæus, 1767), followed by many writers.
Webster's Revised Unabridged Dictionary
Gr. a dirty sponge, fr. unwashed; 'a priv. + to wash
A large Aplysia is very common.
"A Naturalist's Voyage Round the World" by Charles Darwin