amphibious angiostrongylus cantonensis animal aquarium australia biological classification bulinus caenogastropoda cambodia china common name ecosystem freshwater genus gill hermaphrodite hong kong indonesia japan lanistes lung marisa cornuarietis mollusca new world orthogastropoda philippines pomacea pomacea bridgesii pomacea canaliculata pomacea paludosa predation protein reproduction schistosomiasis siphon snail taiwan taro trematoda tropics wikimedia commons zoologica scripta