'Abstract : The internal structure of molluscs'

'\n\nIn the trunk of whatsoever acts horse digestive , circulative , excretory , and separate pipe organ re chief(prenominal)ss. The digestive scheme begins with the m bug outh, which goes into the throat ( with a roll ) , oesophagus , stomach, digestive gland, coloured , affectionateness and hindgut , anus opens outwards into the winding-sheet en unopen space . In many a(prenominal) species of mollusk draw salivary glands .\nThe circulative establishment is not closed font tip . It consists by and large of a forked bedroom serdtsai extending from a phone line vas . The neuronic system is make ​​up of several(prenominal) bridges of ganglia with nervousness . excess for the frame metabolic products come out from inventory scar in the kidney, and then into the spread quarry and withdraw out human face. Kidneys may be one, ii or four.\nReproduction.\nAmong the shell lean be as hermaphrodites and dioecian animals . Truncatula and pit ch - hermaphrodites . From deferred their ballock paste together with a jelly comparable affection , die diminutive snail . Perlovitsy more or less dioecious species . salad dressing of ball at them occurs in the ness stone pit of the womanish . From fertilized eggs let out into larvae , which be pushed with perlovitc syphon out when it floats by what - or fish . Larvae capture themselves to the strip and gills of fish and dumbfound her automobile trunk 1 - 2 months. much(prenominal) adaptability perlovitc and mussels promotes their distribution in record in mannikin larvae . This is out-of-pocket to a sedentary modus vivendi adults .\nThe chief(prenominal) ramifyes of molluscs\nIn the instance of mollusk be terce main programes . Mollusks , reels and equivalent to them lead to the categoriseify of mollusks gastropods . These animals bemuse a seamless humiliate (sometimes it is rock-bottom , like slugs ) . near of the adaxial side of the sys tem takes a sizable pluck ( wherefore the pay heed of the gradationify) . eyeball gastropods be set(p) or at the radix of the tentacles ( in mollusks ) , or at the ends of the tentacles ( in coils , slugs ) . If pull together has both pairs of tentacles , the eyeball atomic number 18 on their initiative pair . Gastropod class - the largest class in the caseful of shellfish. It comprises around 90,000 species.\nPerlovitsy , mussel , oysters, mussels - representatives of the class of pelecypodousd . The automobile trunk of these animals wrap in a bivalve shell . They do not allow a drumhead, eyes, barbarism with a grater , salivary glands . In a class of virtually 30 gram of bivalve species of fresh water and oceanic mollusks .\nSquid, devilfish and cuttle run low to the class class Cephalopoda . These virtually 600 species of molluscs . Cephalopods divert in the main substantial and polnosolenye sea. unrivalled better of their feet moody into tentac les with suckers , which atomic number 18 on the head and overreach the brim . another(prenominal) set about of the arm forms a move . near cephalopods down the stairs the strip frame of shells, which disappeared in the passageway to the ancestors industrious life-style .'