NE Atlantic from the Arctic to the wstern Mediterranean.
6 metres on a reef near Craig'n Gelt at Dunbar, east coast of Scotland. 27 May 2001. Photo: Jime Anderson.
Grows to 30mm in length but seldom longer than 20mm. Feeds on the soft coral Alcyonium digitatum with paler animals on white colonies and darker coloured animals on yellow colonies.
• Johnston, G. (1828). A few remarks on the class Mollusca, in Dr. Fleming's work on British Animals; with descriptions of some new species by George Johnston, M.D. Fellow of the Royal College of Surgeons of Edinburgh. Edinburgh New Philos. Journ. 5: 74-81
Rudman, W.B., 2001 (June 5) Tritonia plebeia Johnston, 1828. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/tritpleb