The siphonophores are an order of marine animals in the phylum Cnidaria (the same phylum containing jellyfish). Although they superficially resemble jellyfish, each siphonophore specimen is actually a colony of many genetically identical individuals called zooids. Each zooid is specialized to serve a particular function within the colony—so much so that most cannot survive alone. The infamous and venomous Portuguese man o' war is a member of this order. Certain siphonophore species can emit lightA species in the Erenna genus found off the coast of Monterey, California has stinging cells that glow red, probably to attract the small fish upon which it preys. This species is only the second life form known to produce a red light, the first being the scaleless dragonfish (Chirostomias pliopterus).



Ernst Haeckel, Kunstformen der Natur / Biodiversity Heritage Library