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Marine fireworks

A siphonophore, which is closely related to the medusae. These animals are made up of multiple units, each specialized for a function like swimming, feeding, or reproduction. This “modular” construction allows some siphonophores to grow very large, over 100 feet long in the deep ocean. Although most siphonophores live below the surface, the Portuguese Man o’ War is one that rests on the surface, suspended by a gas-filled float. (Photo by Larry Madin, Woods Hole Oceanographic Institution)