Velutina plicatilis (O. F. Müller, 1776)
Maximum length, excluding protruding foot and tentacles, is about 18 mm.
Thick un-fused mantle lobes (1) can overlap a short way onto the exterior of the shell, but not sufficiently to cover it.
The thin, translucent shell consists mainly of periostracum with a velvet-like texture through which the yellow/orange/brown viscera are visible within. It is often mistaken for the mantle of a Lamellaria or a dorid seaslug. Epizooic organisms such as barnacles (2) may adhere to the shell.
Sublittoral. Moray coast, N.E. Scotland. May 2018. Leg. & © C. Rickard.

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