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The mantle cavity is a central feature of molluscan biology. This cavity is formed by the mantle skirt, a double fold of mantle which encloses a water space. This space contains the mollusk's gills, anus, osphradium, nephridiopores, and gonopores. The mantle cavity functions as a respiratory chamber in most mollusks. In bivalves it is usually ...
Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks [a] (/ ˈ m ɒ l ə s k s /). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda . [ 5 ]
There is no marked distinction between head and mantle. The tentacles, situated close to the mouth, are used for orientation. Behind them are the rhinophores, olfactory organs which often have complex forms. The middle part of the foot is the sole, used for locomotion. The sides of the foot have evolved into parapodia, fleshy winglike outgrowths.
The siphon is part of the mantle of the mollusc, and the water flow is directed to (or from) the mantle cavity. A single siphon occurs in some gastropods. In those bivalves which have siphons, the siphons are paired. In cephalopods, there is a single siphon or funnel which is known as a hyponome.
Natural pearls form when a small foreign object gets stuck between the mantle and shell. Pearls for use as jewellery are cultured by inserting either "seeds" or beads into oysters. The "seed" method uses grains of ground shell from freshwater mussels , and overharvesting for this purpose has endangered several freshwater mussel species in the ...
Mantle: The mantle is the organ that produces shells for most species of mollusca. In snails, the mantle secretes the shell along the snail shell opening, continuously growing and producing the shell for the entirety of the snail’s life. [ 8 ]
(In mollusks, the mantle consists of the tissues that normally generate the shell. Being mostly or entirely without shells, most slugs have reduced mantles.) Pilsbry (1948) stated that "the enormously developed mantle , the large empty shell sac, and the insertions of the free retractor muscles along the margins of the foot cavity, instead of ...
Some species brood the eggs within the mantle cavity, and the species Callistochiton viviparus even retains them within the ovary and gives birth to live young, an example of ovoviviparity. The egg has a tough spiny coat, and usually hatches to release a free-swimming trochophore larva, typical of many other mollusc groups.