Bougainvillia bella Hartlaub, 1897 accepted as Bougainvillia britannica (Forbes, 1841) (source of synonymy)
Bougainvillia britannica var. coeca Hartlaub, 1911 accepted as Bougainvillia britannica (Forbes, 1841) (original description)
Bougainvillia ramosa nana Hartlaub, 1911 accepted as Bougainvillia muscus (Allman, 1863) (original description)
Bougainvillia triestina Hartlaub, 1911 (original description)
Bougainvillia xantha Hartlaub, 1897 accepted as Bougainvillia britannica (Forbes, 1841) (source of synonymy)
Cubogaster Haeckel, 1879 accepted as Lizzia Forbes, 1846 (source of synonymy)
Cubogaster gemmascens Haeckel, 1879 accepted as Lizzia blondina Forbes, 1848 (source of synonymy)
Lizzia claparedei Haeckel, 1879 accepted as Lizzia blondina Forbes, 1848 (source of synonymy)

Celtic Sea for Turritopsis polycirrha (Keferstein, 1862)  (origin: native)
English Channel for Turritopsis polycirrha (Keferstein, 1862)  (origin: native)
Inner Seas off the West Coast of Scotland for Turritopsis polycirrha (Keferstein, 1862)  (origin: native)
Irish Sea for Turritopsis polycirrha (Keferstein, 1862)  (origin: native)
North Sea for Turritopsis polycirrha (Keferstein, 1862)  (origin: native)
Trieste for Bougainvillia triestina Hartlaub, 1911 

 Status

 for Cubogaster dissonema Haeckel, 1879

With its 8 oral tentacles it is referrable to Lizzia octostyla, which is most likely a synonym of Lizzia blondina [details]