Cirrina

Cirrina or Cirrata is a suborder and one of the two main divisions of octopuses. Cirrate octopuses have a small, internal shell and two fins on their head, while their sister suborder Incirrina has neither. The fins of cirrate octopods are associated with a unique cartilage-like shell in a shell sac. In cross-section, the fins have distinct proximal and distal regions, both of which are covered by a thin surface sheath of muscle.

Cirrina
Oral view of Cirrothauma murrayi showing single row of suckers and paired cirri
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Order:	Octopoda
Suborder:	Cirrina Grimpe, 1916 sensu Felley et al., 2001
Families
Opisthoteuthidae Cirroteuthidae Stauroteuthidae Cirroctopodidae
Synonyms
Cirrata Grimpe, 1916 Cirroctopoda Young, 1989

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. Cirrate octopuses are noteworthy for lacking ink sacs.