Finned deep-sea octopuses, of the genus Grimpoteuthis (Robson 1932), consist of about 17 known species and are poorly known. All octopuses in the genus Grimpoteuthis are nicknamed “dumbo octopuses,” due to the ear-like fins that protrude from the sides of their mantles just above their eyes which resemble the elephant ears of the Disney character Dumbo.
Grimpoteuthis octopuses are part of the Cirrina suborder. Cirrates differ from other octopuses by generally having abandoned jet propulsion, relying on their fins as their primary mode of locomotion. Their two large fins are also supported by an internal shell (another aspect that differs from other octopuses, who generally have no shells of any kind). Their arms are webbed, often with their webbing reaching to the tips of their arms. Suckers are present in a single row along the length of each arm, as well as cirri (fleshy papillae or nipple-like structures along the bottom edges of the arms, see the cephalopod glossary for more details), generally two per sucker. Ink sacs and anal flaps are generally absent. Ink sacs are organs composed of a gland that secretes ink, a sac that stores ink, and a duct that connects it to the rectum. The ink sac generally appears black from the outside although it may be covered by silvery tissue in some species.