Cirrina's a suborder of the order Octopoda. Cirrina octopuses have a small, internal shell and two fins on their head, while their sister suborder, the Incirrina has neither. The suborder's named for small cilia-like strands on the arms of the octopus. There's a pair of cirri for each sucker. These are thought to play some role in feeding, perhaps by creating currents of water that help bring food closer to the beak. Classification CLASS CEPHALOPODA Subclass Nautiloidea: nautilus Subclass &… (More on Cirrina)