Cerata

Cerata are dorsal and lateral outgrowths on the upper surfaces of the body of these nudibranchs.

Cerata greatly extend the surface area of nudibranchs and aid in respiration, the process of gas exchange for metabolic use.

These nudibranchs eat stinging celled animals (Cnidarians) such as anemones, hydroids and sea fans or Portuguese men o' war.

The stinging cells or nematocysts are passed unharmed through the digestive system to cnidosacs at the tips of the cerata.

The dropped cerata produce a sticky secretion and wriggle energetically for some time after being cast off, presumably causing a distraction and allowing the nudibranch to escape.

Detail of the aeolid nudibranch Flabellina aff. lineata showing the cerata and cnidosacs .
Drawing of cerata of Fiona pinnata . There are small efferent vessels in cerata with puckered membranous fringe on the inner sides. The vessels are leading to the great median trunk.