Marrella splendens's an arthropod known from the Middle Cambrian Burgess Shale of British Columbia. It's the most common fossil in the Burgess Shale. History Marrella was the first fossil collected by Charles Walcott from the Burgess Shale. Walcott described Marrella informally as a "lace crab" and described it more formally as an odd trilobite. It was later reassigned to the now defunct class Trilobitoidea in the Treatise on Invertebrate Paleontology. In 1971, Whittington did a thorough redesc… (More on Marrella)