Acaulis primarius Stimpson, 1853 (redescription)
Boreohydra simplex Westblad, 1937 accepted as
Plotocnide borealis Wagner, 1885 (redescription)
Ectopleura L. Agassiz, 1862 (redescription)
Ectopleura larynx (Ellis & Solander, 1786) (additional source)
Eudendrium capillare Alder, 1856 (redescription)
Eudendrium rameum (Pallas, 1766) (additional source)
Eudendrium ramosum (Linnaeus, 1758) (additional source)
Euphysa aurata Forbes, 1848 (redescription)
Hydractinia proboscidea (Hincks, 1868) (redescription)
Plotocnide borealis Wagner, 1885 (redescription)
Stylaster gemmascens (Esper, 1790) (redescription)
Stylaster norvegicus (Gunnerus, 1768) (redescription)
Tubularia indivisa Linnaeus, 1758 (redescription)
Diagnosis
Comprises Codonium proliferum (Forbes, 1884) and similar Corynidae with medusa that bud secondary medusae from ... [details]
Diagnosis
Stolonal hydroid colonies, polyps monomorphic, hydranths either sessile or with a perisarc-covered pedicel. ... [details]
Distribution
North Atlantic from Denmark Strait, east of Greenland, northwest of Iceland through Faroes-Hebrides area to Norway ... [details]
Taxonomy
The taxonomic position is unclear due to the very simple morphology. [details]