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The colour patterns of the corkwing wrasse Crenilabrus tnelops and the functional significance of these patterns has been described. The resting colours of the fish are described for juveniles, mature males and mature females. These colour patterns assist in making the fish less conspicuous in their natural environment. Agonist behaviour is characterized by the development of a series of vertical bars on the body together with ritualized lateral and frontal displays in aggressive, and a head-up submissive posture in fright situations. Most aggressive behaviour is associated with the territorial activity of the mature male. Courtship and spawning activities involve a complex series of visual signals that synchronize the roles played by the male and female. The differences in colouration between juvenile and mature fish and the changes any individual can display have wrongly lead earlier authors to split C. melops into different species or varieties.

The defensive behaviour of 11 species of sea anemone when attacked by the nudibranch Aeolidia papillosa is described. An attempt is made to correlate their defensive responses with the habitat, and with the food preferences of Aeolidia. Actinia equina responds first by tentacle and column retraction, and then by inflation of the column, pedal locomotion, and detachment from the substrate. Anthopleura elegantissima responds in similar ways, but Anemonia sulcata, which has much longer tentacles, uses these in active defence against the eolid. Anemonia also crawls away but it does not detach.Actinia, Anthopleura and Anemonia are the preferred foods of Aeolidia. They commonly live in dense colonies where locomotion and detachment are likely to result in escape. Tealia felina is less preferred and is much less responsive when attacked by Aeolidia.Anemones which possess acontia normally eject these when they are attacked by Aeolidia. Although Aeolidia does occasionally eat acontian anemones, evidence is presented which suggests that acontia have some deterrent effect on this predator. Although most acontian anemones are probably able to move by pedal locomotion and to detach from the substrate, these responses are much less frequently given than by Actinia equina.