The ciliates are a group of protozoans characterized by the presence of hair-like organelles called cilia

Cilium

A cilium is an organelle found in eukaryotic cells. Cilia are slender protuberances that project from the much larger cell body....

, which are identical in structure to flagella

Flagellum

A flagellum is a tail-like projection that protrudes from the cell body of certain prokaryotic and eukaryotic cells, and plays the dual role of locomotion and sense organ, being sensitive to chemicals and temperatures outside the cell. There are some notable differences between prokaryotic and...

 but typically shorter and present in much larger numbers with a different undulating pattern than flagella. Cilia occur in all members of the group (although the peculiar suctoria

Suctoria

Suctoria are sessile ciliates which feed by extracellular digestion and lack cilia in the adult phase. They were originally thought to feed by suction – hence their name. In fact, they use specialized microtubules to ensnare and manipulate their prey...

 only have them for part of the life-cycle) and are variously used in swimming, crawling, attachment, feeding, and sensation.

The term "Ciliophora" is used in classification as a phylum

Phylum

In biology, a phylum The term was coined by Georges Cuvier from Greek φῦλον phylon, "race, stock," related to φυλή phyle, "tribe, clan." is a taxonomic rank below kingdom and above class. "Phylum" is equivalent to the botanical term division....

.