Definitions for "Siphonophora"
An order of pelagic Hydrozoa including species which form complex free-swimming communities composed of numerous zooids of various kinds, some of which act as floats or as swimming organs, others as feeding or nutritive zooids, and others as reproductive zooids. See Illust. under Physallia, and Porpita.
marine colonial hydrozoans
These creatures are a group of organisms related to jellyfish, coral and sea anemones. While they superficially resemble jellyfish, each apparent organism is really a complex colony of multicellular organisms called polyps. The polyps each have their own specific function in the colony but are genetically identical to each other.