Antennular plate with 4 large spines arranged in a square; without scattered small spinules. Third maxilliped with an exopod provided with a flagellum. Transverse grooves of abdominal somites with straight margins, not crenulated, where interrupted, gradually narrowing towards middle of body, not ending abruptly. Colour: abdominal somites: reddish, brownish, sometimes greenish, without transverse colour bands. A large eyespot of whitish or yellowish, surrounded by a dark colour is placed over the anterior end of the base of the pleura of abdominal somite 2,a similar, even slightly larger one in the anterolateral parts of somite 6. Tail fan with a broad transverse reddish band along or just before the posterior margin.
Inhabits shallow waters, occasionally down to 90 m depth, perhaps even deeper. Found among rocks, on reefs, in eelgrass beds or in any habitat that provides protection. The species is gregarious and migratory. Females move to deeper water for spawning and there are mass migrations in the autumn when the animals, in single files of up to 50 individuals, move in a certain direction in daytime, each animal having body contact with the next through the antennae. In the northern part of its range, larvae are found mainly from June to December.