Themantle (also known by theLatin wordpallium meaning mantle, robe or cloak, adjectivepallial) is a significant part of the anatomy ofmolluscs: it is thedorsal 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 theepidermis of the mantle secretescalcium carbonate andconchiolin, and creates ashell. Insea slugs 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’; seemantle (vesture). This anatomical structure in molluscs often resembles a cloak because in many groups the edges of the mantle, usually referred to as themantle 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, thesiphon.
Themantle 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'sgills,anus,osphradium,nephridiopores, andgonopores.
The mantle cavity functions as arespiratory 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 incephalopods and some bivalves such asscallops, it is alocomotory organ.
The mantle is highly muscular. In cephalopods the contraction of the mantle is used to force water through a tubular siphon, thehyponome, 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. InPatella the foot includes the entire ventral surface of the animal. The foot of theBivalvia is a fleshy process adapted by its form to digging rather than to locomotion.
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 theectodermic (epithelial)cells of the mantle tissue.[1]
The mantle of many gastropods is usually fully or partially hidden inside thegastropod shell.
In species where the shell is small compared to the size of the body, more of the mantle shows. Shell-lessslugs have the mantle fully visible. The dorsal surface of the mantle is called thenotum, while the ventral surface of the mantle is called thehyponotum. In the familyPhilomycidae, the mantle covers the whole back side of the body.[2]
 |  |
Cephalopod anatomy | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Shell |
|    | ||||||||||||
| Mantle & funnel |
| |||||||||||||
| Head & limbs |
| |||||||||||||
| General | ||||||||||||||
Developmental stages:Spawn →Paralarva (Doratopsis stage) → Juvenile → Subadult → Adult •Egg fossils •Protoconch (embryonic shell) | ||||||||||||||