Predation and symbiosis in some Upper Cretaceous clionid sponges

Three tests the initial spiral surrounds a surface pore of a clionid sponge boring. The discovery of a similar association between Foraminifera {Placopsilina sp.) and clionid in the Coniacian Chalk at Hope Point near Deal, Kent, England, leads to the discussion of the ecological principles involved. The Coniacian clionid sponge. seems to have been attacked by a predator, the marks of which scar the substrate around the papilla openings to the sponge boring. Encrusting Foraminifera on Campanian oysters in Sweden During the examination of sponge borings in oysters (Arctostrea [Lopha] diluviana (Linnæus)) from the famous shallow-water Campanian locality at Ivo Klack in Scania, Sweden (Voigt, 1929), an example of the ad-herent, arenaceous foraminifer Arenonina cretacea Barnard, 1958 was encountered. The encrusting test was especially remarkable in that its spiral form was neatly coiled round one of the surface pores of a clionid sponge boring system in the substrate shell (fig. 1; pi. 3, fig. 1).