There are a number of different species of the genus Crotalocephalina & Crotalocephalus found in the Devonian rocks of Morocco. The most common of these is Crotalocephalina gibbus. These trilobites have a distinctive bulbous snout, small eyes, and a long, thin body. Average size is between two and three inches. We have authentic, well prepared examples of several species of Crotalocephalina & Crotalocephalus trilobites for sale.