Uncancylus is a genus of small, freshwater, air-breathing limpets, aquatic pulmonate gastropod molluscs in the family Planorbidae, the ram's horn snails and their allies. Anatomy These animals have a pallial lung, as do all pulmonate snails, but they also have a false gill or "pseudobranch" which can serve perfectly well as a gill when they are unable to reach the surface for air. Species Species within the genus Uncancylus include: Uncancylus concentricus (d'Orbigny, 1835) Uncancylus crequi (Bavay, 1904) Uncancylus foncki (Philippi, 1866) Uncancylus patagonicus (Biese, 1948) References Planorbidae