The reason for this is because of the way these trilobites are found. Before preparation, these trilobites are encapsulated in very hard rock. Trilobite diggers will crack pieces of rock and look for any evidence of a trilobite inside. After breaking the rock, if they see part of a trilobite inside, they will glue the rock back together and then carefully prepare the trilobite out of the rock.
It's the fact that they are encapsulated in rock that allows them to often find trilobites with great anatomical details preserved. Many of these repairs are difficult to see or are inconspicuous, but some are easily seen. This is a great piece for any collection! We have a variety of trilobites available so be sure to check out our other listings!