The classification of protozoa based on locomotary organs .In Mastigophora protozoans fiagellum is the locomotory organ. It is long and Thread like. It is useful for locomotion.
Flagella are divided into four types by the arrangement of mastigonemes on the flagellum.

1.Stichonematic : Mastigonemes are in one row. Ex : Euglena

2.Pantonematic : Mastigonemes are in two rows.

3.Acronematic : Flagellum has no mastigonemes, it ends with a fine filament.Ex : Chlatnydomonas.

4.Simple flagellum : This flagellum will not show mastigonemes or end in fibre.Ex : Dinoflagellates.

In Mastigophora organisms one or two or many flagella are seen. If a flagellum drags the organisms it is called Tracteilum. The flagellum which pushes the organisms forward is called Pulsellum.

T.S. Of Flagellum: The flagellum T.S. shows to central fibers. Around them nine pairs of peripheral fibers are present. These fibers are covered by cytoplasmic sheath.

Each flagellum arises 'from a basal granule. The basal granule is also .called Blepharoplast. In some cases the blepharoplast is connected with nucleus, by rhizoplast.

also read pseudopodia in protozoa