Cartoon of major kinetoplastid cell forms. Anterior end of the cell is on the right. Nucleus (gray circle), kinetoplast (gray ellipse), and flagellum emergence points are defined. (A) Trypomastigote. The kinetoplast is located posterior to the nucleus, and the flagellum emerges onto the surface near the kinetoplast and is attached to the cell body along most of its length. (B) Epimastigote. The kinetoplast is located anterior to the nucleus, the flagellum emerges onto the surface near the kinetoplast, and its proximal part is attached to the cell body. (C) Promastigote. The kinetoplast is located anterior to the nucleus and close to the anterior end of the cell. The majority of the flagellum is not attached to the cell body. (D) Amastigote. The kinetoplast is located anterior to the nucleus and close to the anterior end of the cell. The short flagellum does not emerge onto the cell surface but is entirely located in the FP.