Trilobites were prehistoric bottom dwelling marine creatures. They are related to the modern day horse shoe crab. They had a hard exoskeleton body which was conspicuously segmented which enabled them to roll up just as a modern roly- poly. Crotalocephalus is a genus of trilobite that lived from the Late Silurian to the Early Devonian. Its remains have been found in Asia, Australia, Africa, and Europe.
These are great budget pick for starting off your fossil collection or adding to it without breaking the bank.