Phylim Molluska, Class Gastropoda, Family ‪Aeolidioidea,

Aeolidia papillosa


DISTRIBUTION: Common on the Atlantic coast of Europe and North America and the Pacific coast of North America. Also from from both west and east coasts of South America

HABITAT: On rocks, or may be on floats or docks. Often near its perferred prey. Intertidal to 380m deep.

APPEARANCE: Its color appears to be quite variable, depending upon locale and food resources. This large aeolid grows to about 10 cm (4 in)  in length and its body is covered with close obliquely arranged rows of flattened cerata.

DIET: Feeds almost exclusively on sea anemones.

MORTALITY/LONGEVITY:  This species is famous for obtaining undischarged cnidae (cells which bear nematocysts) from its Cnidarian prey and moving to the tips of the cerata , where they are likely used for defense. If disturbed they sometimes wave their cerata. If one of the cerata is broken off, muscles within it contract, expelling the nematocysts, which then discharge . The chemical composition of A. papillosa mucus changes and does not trigger a discharge of nematocysts in the sea anemone.

REPRODUCTION/DEVELOPMENT: Nudibranchs are hermaphroditic, and thus have a set of reproductive organs for both sexes, but they cannot fertilize themselves.

REMARKS: Their eyes are simple and able to discern little more than light and dark. The eyes are set into the body, are about a quarter of a millimeter in diameter, and consist of a lens and five photoreceptors.