RATCHET RIPOSTE - MORE ON GASTROPOD BURROWING SCULPTURE

Recent warnings concerning paleobiological inferences based upon gastr opod shell morphology (Houbrick 1991) merit serious consideration, alt hough the dangers have been overstated, Ratchet sculpture, an asymmetr ical sculpture that assists marine invertebrates in burrowing, is not qualitatively different from sculptures that apparently do not aid in burrowing. Therefore, the interpretation of such sculpture might be pr oblematical. Nevertheless, the large body of empirical evidence demons trating the function of ratchet sculpture in burrowing by bivalves, ga stropods, carpoid echinoderms, brachiopods, and arthropods and the lac k of evidence supporting alternative functions in the Gastropoda warra nt the continued, although cautious, association of ratchet sculpture with burrowing in marine gastropods.