Phylum: Mollusca
Class: Gastropoda
Family: Glaucidae
Genus: Glaucus
Species: Glaucus atlanticus
Common names: Sea swallow, blue glaucus, blue sea slug and blue ocean slug
Glaucus atlanticus (commonly known as: sea swallow, blue glaucus, blue sea slug and blue ocean slug) is a strange species of medium-sized blue sea slug, a pelagic aeolid nudibranch, a marine gastropod mollusk that belongs to the Glaucidae family. It is the only species in the genus Glaucus, but it is closely linked to Glaucilla marginata, yet another member of the family Glaucidae.
