Cerata are dorsal and lateral outgrowths on the body of nudibranchs. Aeolidia papillosa is a Species of sea Slug, an aeolid Nudibranch, a marine Opisthobranch Gastropod In Anatomy, the dorsum is the upper side of animals that typically run fly or swim in a horizontal position and the back side of animals (like humans that walk upright A nudibranch (pronounced (BrE or (AmE is a member of one Suborder of soft-bodied shell-less marine Opisthobranch Gastropod Mollusks The singular is ceras, and the name is from the classical Greek word "keratos" = "horn" and is a reference to its shape. The Ancient Greek language is the historical stage in the development of the Hellenic language family spanning the Archaic (c
These cerata are blood-filled tubes which also contain ducts of the digestive gland. At the tip of the ceras in most aeolid nudibranchs is a sac, called the "cnidosac", which stores stinging nematocysts from the cnidarians (sea anemones, hydroids etc) on which they feed. A cnidocyte, cnidoblast or nematocyte, is a type of Venomous cell unique to the Phylum Cnidaria ( Corals Cnidaria (naɪˈdɛəriə is a phylum containing some 9000 Species of Animals found exclusively in aquatic mostly marine, environments Sea anemones are a group of water dwelling predatory animals of the order Actiniaria; they are named after the Anemone, a terrestrial Flower Hydroid may refer to Marine Biology Colonial plant-like animals closely related to jellyfish with stinging cells any member of the invertebrate order Hydroida (class Aeolids can discharge these nematocysts in their own defence. Some aeolids, such as species of Phyllodesmium which feed on soft-corals, do not have a cnidosac because the nematocysts of soft-corals are of little use in defence. Instead their cerata produce a sticky secretion at their tips. Species of Phyllodesmium are able to break off their cerata when attacked.
Cerata come in many different shapes. As a thin-walled sac of blood it has a major function as a gill, and with a branch of the digestive gland it provides an ideal organ for the exchange of gases and molecules into, and out of, the blood system. The cnidosac also means that the ceras is an important defensive organ. Its ability to change colour also means it is useful in camouflaging the nudibranch.
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