Hydatina
Live individual of Hydatina physis, head end towards the top of the image
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
(unranked):	clade Heterobranchia informal group Lower Heterobranchia
Superfamily:	Acteonoidea
Family:	Aplustridae
Genus:	Hydatina Schumacher, 1817
Species
See text

Hydatina is a genus of sea snails, bubble snails, marine opisthobranch gastropod mollusks in the family Aplustridae.

Species within this genus include:

• Hydatina albocincta Van der Hoeven, 1839
• Hydatina cinctoria Perry, 1811 (color variant and synonym of Hydatina zonata).
  • Distribution: South Africa
• Hydatina exquisita Voskuil, 1995
  • Distribution: Marquesas Islands
  • Length: 21 mm
  • Description: very globose, thin shell with black and purplish spiral bands on body whorl and a narrow white band below the suture and at anterior end: anterior end of the columella is directed slightly to the right.
• Hydatina montilai Delsaerdt, 1996
  • Distribution: Philippines.
• Hydatina physis (Linnaeus, 1758)
• Hydatina velum Gmelin, 1791 (probably color variant and synonym of Hydatina zonata)
  • Distribution: Indian Ocean, East Africa
  • Length: 25–50 mm
• Hydatina vesicaria (Lightfoot, 1786) brown-lined paper bubble
  • Distribution: Florida, Mexico, Caribbean.
  • Length: 17–45 mm
  • Description: lives on the bottom at the depth of 8 m to 64 m; very fragile and delicate shell with fine brown spiral lines
• Hydatina zonata Solander in Lightfoot, 1786 zoned paper bubble

synonyms

• Hydatina amplustre Linnaeus, 1758 accepted as Aplustrum amplustre

• 
  Hydatina albocincta
• 
  Hydatina physis
• 
  Hydatina zonata

• SEM images of the radula can be found at Thompson, T.E.; Bebbington, A. (1973). "Scanning electron microscope studies of gastropod radulae". Malacologia. 14: 147–165.
• Sea Slug Forum info
• Info on the genus