Lanceolate, smooth, brick-red mantle with irregularly wavy, white, longitudinal ridges. When extended, as here, outline is slender, but it can contract to a more stout shape; see image 03 Armina loveni. Length 19.4mm. Sublittoral, Orkney, Scotland. May 2017. Leg. S. Taylor. .
Some specimens, like this one, have a broad, partial, transverse, paler zone near the anterior (1) and another (2) a little more than half way along the mantle from the rhinophores.
The folded cephalic shield is partly unfolded, showing part of the enclosed distal face (3). Length 19.4mm. Sublittoral, Orkney, Scotland. May 2017. Leg. S. Taylor.