Search results
Results from the WOW.Com Content Network
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 .
The bodies of preserved juvenile specimens are up to 3 cm (1.2 in) long with a mantle length of 10 mm (0.39 in). [10] Juveniles reach maturity in two years, at a length about 2.6 cm (1.0 in). [ 10 ] [ 40 ] In the wild, the Kerry slug can live for up to seven years [ 10 ] but in captivity, the lifespan rarely exceeds three years. [ 40 ]
The largest known land gastropod is the African giant snail Achatina achatina, the largest recorded specimen of which measured 39.3 centimetres (15.5 in) from snout to tail when fully extended, with a shell length of 27.3 cm (10.7 in) in December 1978. It weighed exactly 900 g (about 2 lb).
Umbraculum umbraculum is a large mollusc growing to a length of up to 20 cm (8 in), with a relatively small external shell on the dorsal surface. This shell is a flattish cone and is usually encrusted with epiphytic organisms, both plant and animal.
Arca noae is found in the Mediterranean Sea. It was once common in the Adriatic, but in 1949/50 there was a sudden unexplained, catastrophic decline in numbers. Since then, populations have been creeping back upwards, and in 2002, densities of up to 13 individuals per square metre (11 square feet) were recorded.
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 contrast, one of the largest species of freshwater bivalves is the swan mussel from the family Unionidae; it can grow to a length of 20 cm (7.9 in), and usually lives in lakes or slow-flowing rivers. Freshwater pearl mussels are economically important as a source of pearls and mother of pearl. While some species are short-lived, others can ...