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A division of Mollusca having slender, cirriform appendages near the mouth; the Scaphopoda.

A soft tactile appendage of the mantle of many Mollusca, and of the parapodia of Annelida. Those near the head of annelids are Tentacular cirri; those of the last segment are caudal cirri.

That class of Mollusca which includes the bivalve shells; the Lamellibranchiata. See Mollusca.

The science of Mollusca, and of the shells which they form; malacology.

Having a head; -- said of most Mollusca; -- opposed to acephalous.

Pertaining to the epipodium of Mollusca.

One of the classes of Mollusca, of great extent. It includes most of the marine spiral shells, and the land and fresh-water snails. They generally creep by means of a flat, muscular disk, or foot, on the ventral side of the body. The head usually bears one or two pairs of tentacles. See Mollusca. [Written also Gasterop…

The division of Mollusca which includes the land snails and slugs.

A digestive gland in Crustacea, Mollusca, etc., usually called the liver, but different from the liver of vertebrates.

Characterized by a current which flows inward; as, the incurrent orifice of lamellibranch Mollusca.

A class of Mollusca including all those that have bivalve shells, as the clams, oysters, mussels, etc.

An extensive group of Invertebrata, including the Mollusca, Brachiopoda, and Bryozoa. Called also Malacozoaria.

One of the Mollusca. [Written also mollusc.]

One of the cells which secrete the chitinous teeth of Mollusca.

A division of gastropod Mollusca, in which the breathing organs are usually situated behind the heart. It includes the tectibranchs and nudibranchs.

Having the pulmonary sac situated posteriorly; -- said of certain air-breathing Mollusca.

The olfactory organ of some Mollusca. It is connected with the organ of respiration.

A genus of bivalve Mollusca which includes the true oysters.

A division of gastropod Mollusca, including the chitons. The back is covered by eight shelly plates. Called also Polyplacophora. See Illust. under Chiton, and Isopleura.

A class of Mollusca in which the anterior lobes of the foot are developed in the form of broad, thin, winglike organs, with which they swim at near the surface of the sea.