Eight expanded gills (1) around the anus (2). Eight contracted gills (3) do not retract out of sight into a single common cavity. Gills are unipinnate with a thick midrib and crooked, variably-sized pinnae and are arranged around the anus with a posterior gap occupied by a tubercle (4). Outer Hebrides, April 2018. Leg. D. McKay & S. Taylor.