Red-brown discs with about six black-brown peripheral spots and a central spot iridescing between azure blue and emerald. The rhinophores are laterally compressed, smooth cylinders, with a truncate apex and two or three transverse, brown bands.
Left: inner faces of rhinophores. Menai Strait, Wales. March 2012.
Right: outer face of rhinophore. Alder & Hancock (1845-55).