Cirrate octopuses have a small, internal shell and two fins on their head, while their sister suborder Incirrina has neither.

In cross-section, the fins have distinct proximal and distal regions, both of which are covered by a thin surface sheath of muscle.

The suborder is named for small, cilia-like strands (cirri) on the arms of the octopus, a pair 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.

[1] A molecular phylogeny based on mitochondrial and nuclear DNA marker sequences by Sanchez et al., 2018, shows that the Cirrina is paraphyletic, i.e. it is not a single clade.