The body is soft, narrow, and elongate (almost sinuous) and the mantle skirt is absent. Along each side of the dorsum are several pairs of cerata-like papillae, sometimes branched, each protecting one or two small bushy gills that are attached near the base medially. Each side of the mouth an oral tentacle presents as a palm-like paddle bearing five to ten pointed papillae. The rhinophores have a lamellate club and a tall sheath that is usually branched and resembles the papillae on the body. Some species are able to swim by lateral flexions of the body so they resemble an eel when in motion. They feed upon small hydroids.