Which protozoa bear the greatest resemblance to the ancient flagellates?

If we talk about the simplest, then this is exactly the ciliate shoe. It is a single-celled protozoan. This creature got its name because of the resemblance to the sole of a shoe. The body shape of this protozoan is constant. It is also worth knowing that the size of this creature does not exceed three millimeters. On the surface of the body of the ciliate there are numerous cilia, their number can reach fifteen thousand.