These are outgrowths of the body wall that increase the area available for respiration, and contain extensions of the gut, so vary in colour according to the animal's diet.

The cerata are tipped with cnidosacs containing stinging cells, derived from the sea anemones that the nudibranch has eaten and which pass unmetabolized through its body.

It also feeds on Metridium dianthus, Sagartiogeton laceratus, Paractinia striata, Actinothoe sphyrodeta Aiptasia mutabilis, Anemonia viridis and Aulactinia verrucosa.

[3] The rhinophores are sensory structures and are able to analyse the chemicals dissolved in the water around the sea slug, enabling it to detect its prey.

When close enough (fractions of a millimetre), the cnidosacs in the collar cerata are discharged into the column of the anemone, poisoning the tissues and causing necrosis.