Mastigonemes are lateral "hairs" that attach to protistan flagella.
[1] 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.
Typology of flagella with hairs:[2][3][4][5][6] Observations of mastigonemes using light microscopy dates from the nineteenth century.
[7][8][9][10][11] Considered artifacts by some, their existence would be confirmed with electron microscopy.