A phylum of exclusively marine organisms, formerly included in the jellyfish and polyps as coelenterates. These animals, the so-called comb jellies, possess a biradial symmetry of organization. They are characterized by having eight rows of comblike plates (ctenos = comb) as the main locomotory structures. Most of these animals are pelagic, but a few genera are creeping. Many are transparent and colorless; others are faintly to brightly colored. Many of these organisms are hermaphroditic. Development is biradially symmetrical, with a cydippid larval stage. Five orders constitute this phylum as follows:

• Phylum Ctenophora
• Order: Cydippida
• Lobata
• Cestida
• Platyctenida
• Beroida