See text Laevapex 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.
It is widespread throughout the eastern United States, occurring in lakes and slow-flowing rivers.
[3] 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.
[3] Members of this genus are characterised by their smooth apex.
The Animal Diversity Web - University of Michigan.