Pleurophyllidia semperi Bergh, 1861 (basionym) Armina semperi is a species of sea slug, a nudibranch, a marine gastropod mollusk in the family Arminidae.

erythraea Pruvot-Fol, 1933 This species can be identified by the thin black and white ridges that run longitudinally down its back.

The animal also has a characteristic light-blue foot rimmed in yellow-orange, with a matching oral veil.

[2] Members of this species are generally between 2-6 centimeters long, with narrow bodies.

[3] A picture of Armina semperi can be viewed on the online "Sea Slug Forum" website.