The long fins are roughly diamond-shaped and make up two thirds of the total length of the body.

The colour of the squid is variable, but is usually a shade of pink, red, or brown.

The male delivers sperm into the mantle of the female using structures on a specialized tentacle.

[6] Peak spawning season is in January through March off Scotland, with recruitment of juveniles occurring in the fall.

[9] The diet includes fish, polychaetes, crustaceans, and other cephalopods,[10] often members of its own species.