Portuguese man o' war
The Atlantic Portuguese man o' war lives at the surface of the ocean. The gas-filled bladder, or pneumatophore, remains at the surface, while the remainder is submerged. As the Portuguese man o' war has no means of propulsion, they move according to the winds, currents, and tides. Although they are most commonly found in the open ocean in tropical and subtropical regions, they have been found as far north as the Bay of Fundy, Cape Breton and the Hebrides.
Portuguese man o' war
Being a colonial siphonophore, the Portuguese man o' war is composed of three types of medusoids (gonophores, siphosomal nectophores, and vestigial siphosomal nectophores) and four types of polypoids (free gastrozooids, gastrozooids with tentacles, gonozooids, and gonopalpons), grouped into cormidia beneath the pneumatophore, a sail-shaped structure filled with gas. The pneumatophore develops from the planula, unlike the other polyps. This sail is bilaterally symmetrical, with the tentacles at one end. It is translucent, and is tinged blue, purple, pink, or mauve. It may be long and may extend as much as above the water. The Portuguese man o' war fills its gas bladder with up to 14% carbon monoxide. The remainder is nitrogen, oxygen, and argon—atmospheric gases that diffuse into the gas bladder. Carbon dioxide also occurs at trace levels. The sail is equipped with a siphon. In the event of a surface attack, the sail can be deflated, allowing the colony to temporarily submerge.