This individual was ~2 cm long. Note the darker orange-tipped rhinophores (chemosensory tentacles) on the head and the branched white gill plume at the posterior end (below).
Limacia cockerelli feeds exclusively on the bryozoan Hincksina velata.
This specimen was ~3 cm long. Note the narrow yellow border along the edge of the mantle and the foot (trailing behind) and the numerous yellow-capped papillae. The rhinophores and gill plume are gray/white in this individual.
Cadlina luteomarginata feeds on a variety of sponges, but apparently prefers Aplysilla glacialis.
P.S. Both of these species are members of the Superfamily Doridoidea, often shortened to "dorid." Dorid is derived from Doris, a sea nymph in Greek mythology.