This species lives in the northeastern Atlantic, from Norway to the Mediterranean Sea as well as all around the South African coast.

It is found from the intertidal zone to a depth of about 5 m. The animal grows up to 30 mm in total length.

It has a smooth bright green or brown body with iridescent spots and two wing-like flaps extending along its sides.

[1] This species lives in a subcellular endosymbiotic relationship with chloroplasts derived from the alga Codium fragile.

The slug retains the chloroplasts within its cells in a functioning state; they apparently are physiologically important to the host.