Most of 378 upper Eifelian crinoid columnals collected from the lower part of Skaly Beds in the Holy Cross Mountains display traces of borings produced by endobionts, but only approximately 20% of them show traces of epibionts. These infested crinoids are represented by 5 stem-based species: Tantalocrillus scutellus, Schyschcatocrinus creber, Gilbertsocrinus vetulus, Pentagonostipes petaloides, and Cycloocetocrinus sp. They were fouled by 19 species of suspension-feeding epibionts, including saccamminid foraminiferans, rugose and tabulate corals, cyrtinitid and productid brachiopods, "ctenostome bryozoans", "cyclostome bryozoans", cystoporate bryozoans, and rhabdomesid? bryozoans, crinoids, and organisms of uncertain affinities. The majority of these epibionts were opportunistic commensals colonizing living crinoids, and only some utilized dead crinoids as hard substrate for attachment. At least some of these epibionts seem to have settled selectively on particular crinoid host species.