. . . . . "Respiratory system of gastropods"@en . . . . . . . . . . . . . . . . . . . "7475"^^ . . . . . "1110496291"^^ . . . . . . . . . . . . . . . . . . . . . . . "The respiratory system of gastropods varies greatly in form. These variations were once used as a basis for dividing the group into subclasses. The majority of marine gastropods breathe through a single gill, supplied with oxygen by a current of water through the mantle cavity. This current is U-shaped, so that it also flushes waste products away from the anus, which is located above the animal's head, and would otherwise cause a problem with fouling. In the pulmonate gastropods, which are found on both land and in freshwater, the gill has been replaced by a simple lung."@en . . . . . . . . "23772561"^^ . . . "The respiratory system of gastropods varies greatly in form. These variations were once used as a basis for dividing the group into subclasses. The majority of marine gastropods breathe through a single gill, supplied with oxygen by a current of water through the mantle cavity. This current is U-shaped, so that it also flushes waste products away from the anus, which is located above the animal's head, and would otherwise cause a problem with fouling. In the pulmonate gastropods, which are found on both land and in freshwater, the gill has been replaced by a simple lung."@en . . . . . . . . .