abstract:Pteropoda (common name pteropods, from the Greek meaning "wing-foot") is a term applied to what are now considered to be two separate taxonomic groups of specialized free-swimming pelagic sea snails and sea slugs, marine opisthobranch gastropods. The word "Pteropoda" no longer has a scientifically precise use, but the vernacular name "pteropods" is still used sometimes as a convenience.