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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 ...
Terrestrial molluscs or land molluscs (mollusks) are an ecological group that includes all molluscs that live on land in contrast to freshwater and marine molluscs. They probably first occurred in the Carboniferous , arising from freshwater ones .
Cornu aspersum (formerly Helix aspersa) — a common land snail. 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]
The mollusc (or mollusk [spelling 1]) shell is typically a calcareous exoskeleton which encloses, supports and protects the soft parts of an animal in the phylum Mollusca, which includes snails, clams, tusk shells, and several other classes. Not all shelled molluscs live in the sea; many live on the land and in freshwater.
The shell of Stenotrema florida, a land snail. The periostracum is an organic layer of protein which, in this species, is developed into minute hairs, giving the snail a velvety look and feel. Conchiolins (sometimes referred to as conchins) are complex proteins which are secreted by a mollusc's outer epithelium (the mantle).
The bivalve's two siphons are situated at the posterior edge of the mantle cavity. [11] There is an inhalant or incurrent siphon, and an exhalant or excurrent siphon. [12] The water is circulated by the action of the gills. Usually water enters the mantle cavity through the inhalant siphon, moves over the gills, and leaves through the exhalant ...
(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 ...
This class comprises snails and slugs from saltwater, freshwater, and from the land. There are many thousands of species of sea snails and slugs, as well as freshwater snails, freshwater limpets, land snails and slugs. The class Gastropoda is a diverse and highly successful class of mollusks within the phylum Mollusca.