Tritonia hombergii
Cuvier, 1803

Family: Tritoniidae


Northeastern Europe from Norway to Mediterranean coast of Spain.


UPPER RIGHT: United Kingdom, Scotland, Isle of Cumbrae, Millport, intertidal, May 1993.
LOWER PHOTOS: Left - egg mass, Right - subadult. United Kingdom, Scotland, Outer Hebrides, St. Kilda, Boreray, 23m, vertical wall, 1993. PHOTOS: Daniel Geiger.

This large nudibranch grows to over 200mm in length. The body colour changes as the animal ages from white to the mottled colour in the photos. Juveniles were originally considered a different species Tritonia alba and because the radular morphology changes from juveniles to adults, the discovery they were the same species was relatively recent. Many aspects of its anatomy and biology were studied extensively by the late Tom Thompson. It feeds in the softcoral Alcyonium digitatum and despite its large size, has an annual life cycle.

Note added 17 May 2007: The spelling of the name on the Forum as T. hombergi has been corrected to T. hombergii. See message #19914.

  • Thompson, T.E. & Brown, G.H. (1984) Biology of Opisthobranch Molluscs, Vol 2. Ray Society: London.

Authorship details
Rudman, W.B., 1999 (September 16) Tritonia hombergii Cuvier, 1803. [In] Sea Slug Forum. Australian Museum, Sydney. Available from

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