[2] Unlike Rhabdopleura, Cephalodiscus species do not form large colonies and are only pseudocolonial, but they do share a common area with individual buds for each zooid.

[2] Cephalodiscius are endemic to the Antarctic and Southern Ocean, whose relative inaccessibility has historically limited human study of the genus.

[2] The Erebus and Terror may have unwittingly encountered C. nigrescens specimens, and the Challenger C. densus; but until the Swedish Antarctic Expedition of 1901-1903, only C. dodecalphus had been identified.

[5] In 1882, M'Intosh (later spelled McIntosh) had identified Dodecalphus from dredged Magellanic-Straits material, work published 5 years later, but the discovery left cephalodiscid phylogeny unclear.

The Swedish expedition provided a plethora of new species, and subsequent researchers began to recognize cephalodiscid species in the relatively temperate waters off South Africa, the Falklands, Sri Lanka, and Australia.