Cerata have transparent, colourless apical zone (1) with internal elongate, white cnidosac (2) and opaque white freckles (3) near the tip. The brown or yellowish brown digestive gland fills the rest of each ceras and is sometimes arranged in transverse bands (4). Dense white freckles may appear yellowish when over the brown digestive gland.
Left: length 6 mm, LWS, Menai Strait, Wales, April 2011.
Right: south-east Scotland, June 2017. © J. Anderson.