Here's a breakdown:

* Axial filaments: This is the most common term used to describe these structures.

* Endoflagella: This term highlights their location within the periplasmic space, between the cell wall and the outer membrane.

Key characteristics of axial filaments:

* They are located within the periplasmic space of spirochete bacteria.

* They are bundles of fibrils that wrap around the cell.

* Their rotation causes the cell to move in a corkscrew motion.

Examples of bacteria with axial filaments:

* *Treponema pallidum* (the bacterium that causes syphilis)

* *Borrelia burgdorferi* (the bacterium that causes Lyme disease)