View source for Biology:Mantle (mollusc)

{{short description|Part of the anatomy of molluscs}}
[[Image:Loligo vulgaris.jpg|thumb|[[Biology:European squid|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.]]
[[Image:Giant clam komodo.jpg|thumb|The brightly coloured mantle of a [[Biology:Giant clam|giant clam]] protects it from bright sunlight.]]
[[Image:HPIM1795.JPG|thumb|The [[Biology:Cuttlefish|cuttlefish]] uses its mantle cavity for jet propulsion]]
The '''mantle''' (also known by the [[Social:Latin language|Latin]] word '''pallium''' meaning mantle, robe or cloak, adjective '''pallial''') is a significant part of the anatomy of [[Biology:Mollusc|mollusc]]s: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself. 

In many species of molluscs the epidermis of the mantle secretes [[Chemistry:Calcium carbonate|calcium carbonate]] and conchiolin, and creates a [[Biology:Mollusc shell|shell]]. In [[Biology:Sea slug|sea slug]]s there is a progressive loss of the shell and the mantle becomes the dorsal surface of the animal.

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, usually referred to as the ''mantle margin'', 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 [[Biology:Siphon (mollusc)|siphon]].

== 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 contains the mollusk's [[Biology:Gill|gill]]s, [[Biology:Anus|anus]], [[Biology:Osphradium|osphradium]], nephridiopores, and [[Biology:Gonopore|gonopore]]s. 

The mantle cavity functions as a [[Biology:Respiration (physiology)|respiratory]] chamber in most mollusks. 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 [[Biology:Scallop|scallop]]s, 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 gastropods it is used as a kind of "foot" for locomotion over the surface. In ''[[Biology:Patella (gastropod)|Patella]]'' the foot includes the entire ventral surface of the animal. The foot of the [[Biology:Bivalvia|Bivalvia]]  is a fleshy process adapted by its form to digging rather than to locomotion.

== Formation of mollusc shell ==
{{further|Biology:Mollusc shell}}

In shelled molluscs, the mantle is the organ that forms the shell, and adds to the shell to increase its size and strength as the animal grows. Shell material is secreted by the [[Biology:Ectoderm|ectoderm]]ic (epithelial) [[Biology:Cell|cells]] of the mantle tissue.<ref>"integument (molluscs)." Encyclopædia Britannica. 2009. Encyclopædia Britannica 2006 Ultimate Reference Suite DVD</ref>

==Mantle of gastropods==
The mantle of many gastropods is usually fully or partially hidden inside the [[Biology:Gastropod shell|gastropod shell]].

<gallery>
File:Cypraea chinensis with partially extended mantle.jpg|The marine gastropod ''Cypraea chinensis'', the Chinese cowry, showing its partially extended mantle.
File:Cypraea chinensis with fully extended mantle.jpg|''Cypraea chinensis'' with its mantle fully extended.
File:SnailWynaad.jpg|The mantle of the land snail  ''[[Biology:Indrella ampulla|Indrella ampulla]]'' is off-white in color and partly visible under the shell. The head and foot are red, and the foot fringe is off-white with narrow black lines.
File:BEP 7909-1.jpg|The mantle of the nudibranch ''[[Biology:Felimida purpurea|Felimida purpurea]]'' has a marginal line of orange-yellow colour.
</gallery>

In species where the shell is small compared to the size of the body, more of the mantle shows. Shell-less [[Biology:Slug|slug]]s have the mantle fully visible. The dorsal surface of the mantle is called the '''notum''', while the ventral surface of the mantle is called the '''hyponotum'''. In the family [[Biology:Philomycidae|Philomycidae]], the mantle covers the whole back side of the body.<ref name="Tsai 2008">Tsai C.-L. & Wu S.-K. (2008). [http://zoolstud.sinica.edu.tw/Journals/47.6/759.pdf PDF "A New ''Meghimatium'' Slug (Pulmonata: Philomycidae) from Taiwan".] ''Zoological Studies'' '''47'''(6): 759-766.</ref>

<gallery>
File:Bielzia coerulans-3.jpg|The mantle and the head of this [[Biology:Slug|slug]] ''[[Biology:Bielzia coerulans|Bielzia coerulans]]'' is smooth, while the rest of the body is tubercled.
File:Megapallifera mutabilis.jpg|''[[Biology:Megapallifera mutabilis|Megapallifera mutabilis]]'' from [[Biology:Philomycidae|Philomycidae]] shows enormously developed mantle
</gallery>

{|
||[[File:Haliotis asinina anatomy.jpg|left|thumb|Photo of ''[[Biology:Haliotis asinina|Haliotis asinina]]'' with the shell removed.]]
||[[File:Haliotis asinina anatomy 2.jpg|left|thumb|This drawing shows that the mantle (in gray) covers the majority of the dorsal surface of the animal.<ref>Daniel J Jackson, Carmel McDougall, Kathryn Green, Fiona Simpson, Gert Wörheide & Bernard M Degnan. 2006. ''[http://www.biomedcentral.com/1741-7007/4/40 A rapidly evolving secretome builds and patterns a sea shell]''. BMC Biology 2006, 4:4. 0 {{doi|10.1186/1741-7007-4-40}}.</ref>]]
|}
<!--Molluscs, in addition to their [[Biology:Operculum (gastropod)|operculum]], protect from desiccation and predators with secreted mucus.-->

== See also ==
* [[Biology:Mollusc shell|Mollusc shell]], which is formed by the mantle
* [[Biology:Siphon (mollusc)|Siphon]], which is a part of the mantle in some groups of molluscs

==References==
{{reflist}}

{{Gastropod anatomy}}

[[Category:Mollusc anatomy]]

{{Sourceattribution|Mantle (mollusc)}}