Natural flint casts representing several different types of burrows were found within the thickness of the test of a Chalk echinoid. They have been compared with the burrows inhabited by various living animals. It is concluded that they indicate the probable presence of an acrothoracican cirripede, a phoronid, and an echiuroid, and the possible presence of a lamellibranch, polychaet and other 'worms', and sponges. No new names are proposed for these burrows because they cannot be regarded as parts of organisms