High Quality Content by WIKIPEDIA articles! The vortex banded mountain snail or whorled mountain snail (Oreohelix vortex) is a species of gastropod in the Oreohelicidae family. It is endemic to the United States.Gastropods (class Gastropoda; previously known as univalves and sometimes spelled Gasteropoda) form a major part of the phylum Mollusca. Gastropods are more commonly known as snails and slugs, and include those that live in the sea, in freshwater, and on land. This class of animals is second to the insects in its number of known species. Its fossil history goes back to the Late Cambrian.