Polygyrid Snails

Polygyridae is a family of air-breathing land snails, terrestrial pulmonated gastropod mollusks. While there are many types of mollusk, the Polygyridae make up a significant proportion of the land snail fauna of eastern North America, and are also found in western North America, northern Central America, and are present on some Caribbean islands. This snail family is distinguished from other gastropods on the basis of several anatomical features: They have no dart apparatus, the muscles which allow the eyes and pharynx to be retracted are united into a single band, and the jaws are ribbed.