Mantle (mollusc)

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European Squid (Loligo vulgaris). The mantle is all that is visible behind the head: the outer body wall and the fins are all part of the mantle.

The brightly coloured mantle of Giant clam protects it from bright sunlight.

The mantle (also known by the Latin word pallium, adjective pallial) is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass.

In many, but by no means all, species of molluscs, the epidermis of the mantle secretes calcium carbonate and conchiolin, and creates a shell.

The words mantle and pallium both originally meant cloak or cape, see mantle (vesture). This anatomical structure in molluscs often resembles a cloak because in many groups the edges of the mantle extend far beyond the main part of the body, forming flaps, double-layered structures which have been adapted for many different uses, including for example, the siphon.

[edit] The mantle cavity

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 containing the mollusc's gills, anus, osphradium, nephridiopores, and gonopores.

The mantle cavity functions as a respiratory chamber in all molluscs. In bivalves it is usually part of the feeding structure. In some mollusks the mantle cavity is a brood chamber, and in cephalopods and some bivalves such as scallops, it is a locomotory organ.

The mantle is highly muscular. In cephalopods the contraction of the mantle is used to force water through a tubular siphon, the hyponome, and this propels the animal very rapidly through the water. In other mollusks, it is used as a kind of "foot" for locomotion.

[edit] Formation of mollusc shell

In shelled molluscs, the mantle is what forms the shell, and what adds to the shell to increase its size and strength as the animal grows. Shell material is secreted by the ectodermic (epithelial) cells of the mantle tissue.^[1]

[edit] Mantle of gastropods

The mantle of many gastropods is fully or partially hidden inside the gastropod shell. In species where the shell is small compared to the size of the body, more of the mantle shows. Shell-less slugs have the mantle fully visible.

The marine gastropod Cypraea chinensis, the Chinese cowry, showing partially extended mantle.

Cypraea chinensis with its mantle fully extended.

The mantle of Indrella ampulla is off-white in color and it is partly visible under the shell. The rest of the body (head and the foot) is red. The foot fringe is off-white with narrow black lines.

The mantle and the head of this slug Bielzia coerulans is smooth, while the rest of the body is tubercled.

[edit] See also

• Mollusc shell is formed by the mantle
• Siphon (mollusc) is a part of the mantle in some species

[edit] References