The stratigraphic value of trilobite burrows has recently been questioned because of a seemingly Ordovician form in the Lower Cambrian of Canada. Closer examination shows, however, that the Cambrian homeomorph ( Cruziana pectinata n. sp.) has a significantly different scratch pattern. This raises the question whether the multiple scratches of the Ordovician Cruziana rugosa were also made by exopodites or by similarly shaped endopodites.