The basal third of the stout, almost linear rhinophores is smooth and coloured as the mantle. The distal two thirds have up to fourteen closely set yellowish lamellae, often with a few flecks of brown pigment. A small, white apex protrudes above the lamellae, and may be visible as a white spot when viewed from above. The margin of the basal rhinophoral cavity has no sheath or rim, only the normal small tubercles of the mantle.
Left: Northumbria. Alder & Hancock (1845-55). Right: Orkney 1975.