02 Berthella plumula. North Wales.

02 Berthella plumula. North Wales.

Puckered and folded mantle is raised (right) into a round-topped dome. Reticulating lines enclose apparently impressed, translucent areas, and resemble lobules of its sponge prey, Oscarella. It superficially resembles a dorid nudibranch, but there are no rhinophores or gill on the mantle surface.