Abstract : The internal structure of molluscs

\n\nIn the body of any acts clam digestive , circulative , excretory , and other organ corpses. The digestive system begins with the mouth, which goes into the throat ( with a float ) , esophagus , stomach, digestive gland, coloured , middle and hindgut , anus opens outbound into the mantel nether region . In umpteen species of mollusc carry salivary glands .\nThe circulatory system is non closed shoot tip . It consists loosely of a dual sleeping room serdtsai extending from a caudex vessel . The spooky system is make ​​up of several(prenominal) pairs of ganglia with nerves . superfluous for the body metabolous products come from linage clams in the kidney, and then into the mantle caries and upstage out incline. Kidneys may be one, twain or four.\nReproduction.\nAmong the shellfish argon as hermaphrodites and dioecian animals . Truncatula and reel - hermaphrodites . From deferred their orchis glued unneurotic with a gelatinous substance , give -up the ghost little escargot . Perlovitsy most dioecian species . Fertilization of orchis at them occurs in the mantle cavity of the female . From fertilized eggs turn out into larvae , which argon pushed through perlovitc syphon out when it floats by what - or fish . Larvae attach themselves to the fell and gills of fish and develop her body 1 - 2 months. much(prenominal) adaptability perlovitc and mussels promotes their distribution in nature in phase larvae . This is payable to a sedentary life-style adults .\nThe primary(prenominal) clubes of molluscs\nIn the typesetters case of shellfish are three main(prenominal) associatees . Mollusks , reels and similar to them fit to the family of mollusks gastropods . These animals ease up a seamless sink (sometimes it is trim down , like slugs ) . around of the ventral side of the body takes a muscular rear end ( hence the describe of the class) . Eyes gastropods are located or at the old bag of the tentacles ( in mo llusks ) , or at the ends of the tentacles ( in coils , slugs ) . If clam has two pairs of tentacles , the eyes are on their world-class pair . Gastropod class - the largest class in the type of shellfish. It comprises close 90,000 species.\nPerlovitsy , mussel , oysters, mussels - representatives of the class of pelecypodous . The body of these animals envelop in a bivalve shell . They do non have a head, eyes, tongue with a grater , salivary glands . In a class of virtually 30 thousand of bivalve species of freshwater and nautical mollusks .\nSquid, octopus and cuttlefish belong to the class Cephalopoda . These about 600 species of molluscs . Cephalopods occupy mostly warm and polnosolenye sea. nonpareil part of their feet turned into tentacles with suckers , which are on the head and environ the mouth . another(prenominal) part of the degree forms a funnel shape . Some cephalopods below the skin dust of shells, which disappeared in the regeneration to the ancestors active lifestyle .