The appendages of the Ordovician trilobiteCryptolithus tesselatusare restudied, and particular reference is made to the exite branch. Details formerly borrowed fromTriarthrusto complete the reconstruction of the appendages ofCryptolithusare now found in part to be significantly different in the two trilobites. The exite ‘filaments’ ofCryptolithusevidently are strong spines that pointed ventrally and may have been used to stir up deposited mud. The broadened view of trilobite appendages indicates that some trace fossils(Cruziana semi‐plicatatype) may be interpreted as being partly made by the exites, while others (C.rugosatype) are perhaps made exclusively by the e