mastigoneme

thumb|right|Schematic drawing of Cafeteria roenbergensis ([[Heterokonta: Bicosoecida) with two unequal (heterokont) flagella: an anterior straminipilous (with tubular tripartite mastigonemes) and a posterior smooth]] thumb|right|A chrysomonad (Heterokonta: [[Chrysophyceae) under TEM, with a smooth flagellum (1) and a long flagellum covered with mastigonemes (3)]] thumb|Two cryptomonads (Cryptophyceae) under SEM. Mastigonemes not visible.

Mastigonemes are lateral "hairs" that attach to protistan flagella. Flimsy hairs attach to the flagella of euglenid flagellates, while stiff hairs occur in stramenopile and cryptophyte protists. Stramenopile hairs are approximately 15 nm in diameter, and usually consist of flexible basal part that inserts into the cell membrane, a tubular shaft that itself terminates in smaller "hairs". They reverse the thrust caused when a flagellum beats. The consequence is that the cell is drawn into the water and particles of food are drawn to the surface of heterotrophic species.