Northeastern Atlantic from Arctic to Atlantic coast of France [including British Isles].
Dunollie Point, Oban on the west coast of Scotland. March 2000. 26 metres on a sponge. Approximately 24 mm long. Photo: Jim Anderson
Grows to approximately 45 mm. The body is a pale translucent yellow or greyish white. The inflated cerata but are packed closely together rather than arranged in rows. The cerata are translucent whitish with an opaque white cap at the tip. On the white is a golden yellow subterminal ring. Each ceras has a dark digestive gland duct. Thompson (1988) notes that juveniles up to 13 mm in length may be white all over, except for the pale brown core to each ceras. It has been recorded from a number of both calyptoblastic and gymnoblastic hydroids, but most characteristically it is found on delicate calyptoblasts such as Obelia geniculata.
• Thompson, T.E. (1988) Molluscs: Benthic Opisthobranchs (Mollusca: Gastropoda). Synopses of the British Fauna (New Series). No. 8. 2nd Edition. E.J.Brill/W. Backhuys: Leiden. 1-356.
Rudman, W.B., 2001 (December 3) Eubranchus tricolor Forbes, 1838. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/eubrtric