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The mantle (also known by the Latin word pallium meaning mantle, robe or cloak, adjective pallial) is a significant part of the anatomy of molluscs: 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 ...
The buccal mass is the first part of the digestive system, and consists of the mouth and pharynx. The mouth includes a radula, and in most cases, also a pair of jaws. The pharynx can be very large, especially in carnivorous species. Many carnivorous species have developed a proboscis, containing the oral cavity, radula, and part of the ...
Mollusca is a phylum of protostomic invertebrate animals, ... The visceral mass, or visceropallium, is the soft, nonmuscular metabolic region of the mollusc. It ...
Torsion is a gastropod synapomorphy which occurs in all gastropods during larval development. Torsion is the rotation of the visceral mass, mantle, and shell 180˚ with respect to the head and foot of the gastropod.
Snails are distinguished by an anatomical process known as torsion, where the visceral mass of the animal rotates 180° to one side during development, such that the anus is situated more or less above the head. This process is unrelated to the coiling of the shell, which is a separate phenomenon.
The heart is muscular and located in the anterior part of the visceral mass. In the great majority of species, it has two chambers; an auricle, which receives haemolymph from the gill or lung, and a ventricle, which pumps it into the aorta. However, some primitive gastropods possess two gills, each supplying its own auricle, so that their heart ...
Body whorl (or last whorl): the largest whorl in which the main part of the visceral mass of the mollusk is found; Columella: the "little column" at the axis of revolution of the shell; Operculum: the "trapdoor" of the shell; Parietal callus: a ridge on the inner lip of the aperture in certain gastropods
This forms two chambers, one on either side of the visceral mass. The ingress chamber is anatomically anterior and the egress chamber is posterior. [ 6 ] : 123–124 Within Ostreoidea, the degree of attachment of the left and right mantle lobes to the visceral mass varies between subgroups.