Scyllaeids have an elongate body that is high in profile and often keel-shaped. There are one or two, large, flap-like ceratal lobes down each side approximately midway along the body length. Many irregularly spaced, bushy and transparent gills are located on the inside face of these cerata. There may be a bilobed oral veil. The rhinophoral sheaths have a similar appearance to the cerata, although smaller. Each rhinophoral sheath surrounds a relatively small, clubbed rhinophore. The rhinophore clubs bear a few horizontal lamellae and becomes a knob at the tip. All species can swim reasonably well by lateral flexions of the body assisted by the large surface area of the cerata and the rhinophoral sheaths. They feed on hydroids that are epiphytic upon brown algae and sea grasses. Some scyllaeids are pelagic in that their food source is found on the brown algae that drift in the ocean currents.