TheEuglenozoaare a large group offlagellateprotozoa. They include a variety of common free-living species, as well as a few important parasites, some of which infect humans. There are two main subgroups, theeuglenidsandkinetoplastids. Euglenozoa are unicellular, mostly around15-40 µmin size, although some euglenids get up to 500 µm long.
Most euglenozoa have two flagella, which are inserted parallel to one another in an apical or subapical pocket. In some these are associated with acytostomeor mouth, used to ingestbacteriaor other small organisms. This is supported by one of three sets ofmicrotubulesthat arise from the flagellar bases; the other two support the dorsal and ventral surfaces of the cell