Chondrophore

Chondrophores
Blue button (Porpita porpita)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Cnidaria
Class:	Hydrozoa
Order:	Anthoathecata
Suborder:	Capitata
Family:	Porpitidae Goldfuss, 1818
Type genus
Porpita
Genera
Porpita Velella
Synonyms
Velellidae Eschscholtz, 1829 Discalidae Haeckel, 1888 Porpalidae Haeckel, 1888 Porpitellidae Haeckel, 1888 Chondrophora Totton, 1954

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 Though it derives from an outdated name for this lineage, some still find the term 'chondrophore' useful as a synonym to 'porpitid' in discussions of the two genera contained therein, Porpita and Velella.

They all live at the surface of the open ocean, and are colonies of carnivorous, free-floating hydroids whose role in the plankton community is similar to that of pelagic jellyfish. 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 most familiar members of the family Porpitidae are the blue button (Porpita porpita) and the by-the-wind sailor (Velella velella).