The following species (possibly) occur in the North Sea, but only the polyp stage is known, the exact medusal stage of each of these species is unknown (Hansson, 1998a).
¥ Tubularia bellis Allman, 1863.
Meduse unknown; polyp occurs in the lower eulittoral and is common in the whole North Sea.
¥ Tubularia indivisa Linnaeus, 1758.
Meduse unknown; the polyp occurs from 0 to at least 280 m depth and is common in the whole North Sea.
¥ Tubularia larynx Ellis and Solander, 1786.
Meduse unknown; the polyp occurs from the lower shore to at least 100 m depth and is common in the whole North Sea. Detached hydranths were occasionally found in the neritic plankton of the Dutch Waddenzee.
¥ Tubularia regalis Boeck, 1860.
Meduse unknown; depth range unknown; concerning the North Sea, the polyp possibly occurs in the Oslofjorden; in the Atlantic Ocean it is found in the NE Atlantic, NE Greenland, Shetlands, along the Norway coast, Spitzbergen, and Nova Zembla.