AbstractThe position of a boring in a cup of the disparid crinoidSynbathocrinus conicusPhillips from Clitheroe, England, suggests various inferences concerning the ecology of the pit‐forming organism. The crinoid cup shows a growth deformity, indicating it must have been alive when infested. The boring is at a triple suture between the E and A ray radials and the EA interray basal, presumably one of five equally weak points on the cup. This site is well removed from the anus and would have been an ideal point of attachment for a filter feeding organism, being well elevated, upcurrent and protecte