Chondrophore

The chondrophores or porpitids are a small group of hydrozoans in the family Porpitidae. Though it derives from an outdated name for this lineage, some find the term chondrophore still useful as a synonym for members of the family Porpitidae – porpitids – when discussing the two genera contained in Porpita and Velella, to avoid confusion with the near-identical genus name Porpita.

They all live at the surface of the open ocean, and are colonies of carnivorous, free-floating hydroids. The chondrophores look like a single organism, but are actually colonial animals, made up of orderly cooperatives of polyps living under specialized sail-structures. The colony's role in the plankton community is similar to that of pelagic jellyfish.

The most familiar members of the family Porpitidae are the blue button (Porpita porpita) and the by-the-wind sailor (Velella velella).