Aeolidia filomenae
Pale body. Translucent pale cerata with flattened faces towards camera. Large white cnidosacs clearly visible in apices of cerata. Distinct white ‘Y’ mark on oral tentacles and head, with stem passing back between the rhinophores. Distance between oral tentacles at base about three times thickness of tentacle base.
Length 19 mm. Outer Hebrides, Scotland. April 2018. Leg. S. Taylor.