Here is a fine example of the Harpetida trilobite Scotoharpes sp. from Morocco. It has a very dramatic "head shield" which is often interpreted as a mechanism to help it stay on top of a soft ocean floor. This preglabellar ring (head shield) is covered in many sensory pits which may have held hairlike features when the trilobite was alive.
This example is enrolled and has been prepared so that it's swept back genal spines are flying above the matrix.