This is a very bumpy, 1.01" long Cyphaspis trilobite from Often, Morocco. Its head is covered in small bumps and it has excellent preparation. About half of the left stalk eye has been restored.
 
Trilobites were a very diverse group of extinct marine arthropods. They first appeared in the fossil record in the Early Cambrian (521 million years ago) and went extinct during the Permian mass extinction (250 million years ago). They were one of the most successful of the early animals on our planet with over 25k currently described species, filling nearly every evolutionary niche. Due in large part to a hard exoskeleton (shell), they left an excellent fossil record.