@article {34, title = {Disarticulated bivalve shells as substrates for encrustation by the bryozoan Cribrilina puncturata in the Plio-Pleistocene Red Crag of Eastern England}, journal = {Palaeontology}, volume = {31}, year = {1988}, chapter = {237}, abstract = {Cribrilina puncturata (Wood, 1844) forms small, patch-like colonies encrusting the concave (almost invariably lower) surface of disarticulated bivalve mollusc shells in the Plio-Pleistocene Red Crag of eastern England. The species is restricted to the deeper central part of each shell, away from the margin. Peripheral abrasion of the shell{\textquoteright}s surface, which might have removed marginal settlement, is rejected as the major agent in producing the observed distribution. A number of larval behaviour mechanisms that might have been responsible are therefore considered. All are discounted except one: that the larva crept up the slope of the shell{\textquoteright}s inner surface towards the highest point (geonegative movement) before fixation. This hypothesis seems to explain many details of the settlement pattern. C. puncturata apparently exploited the shell{\textquoteright}s major concavity as a refuge from physical disturbance in a high-energy environment, and its larval settlement behaviour appears to have been specialized for concavo-convex (bivalve) substrates. A second category of refuge, minor local concavities anywhere on the shell{\textquoteright}s surface, was occupied during the vulnerable early astogenetic stages of two other bryozoan species, both with a runner-like colony morphology.}, author = {Bishop, J.D.D.} }