Hi Phil, Here are the abstracts of the references I suggested to you over on the BBC board. None of them are exaclt what you call general reviews, but hopefully you can get something from them. Enjoy! From Brandt: A comparison of ecdysial patterns between trilobites and other macrobenthic marine arthropods (crabs, shrimp, lobsters, horseshoe crabs) reveals differences that may have evolutionary consequences. Limulus and many malacostracans apparently have a signature ecdysial style; conversely, a range of moult configurations characterized trilobite ecdysis, and this variation is evident even within individual species. A canalised ecdysial habit may be safer or metabolically more efficient and therefore, summed over the history of the class, evolutionarily advantageous. Some trilobite clades show evolutionary trends toward morphologies that would have facilitated ecdysis (e.g. reduction in the number of thoracic segments, reduction in the number and prominence of spines), but co-adaptation or multiple-use effects complicate the evolutionary signal of eedysial selection. Survivorship analysis supports a possible link between ecdysial habit and evolutionary success: genera with fewer thoracic segments (= easier ecdysis) are longer-lived. The increased predation pressure on trilobites through the Palaeozoic would have amplified the evolutionary impact of an inefficient moult habit. The cumulative effects of a less-than-optimal ecdysial habit, and a physiology that apparently required reconstituting a calcitic exoskeleton de novo with each moult, are compelling biotic factors to consider in examining functional interpretations, life histories, evolutionary trends, and ultimate disposition of the Trilobita. From Nedin: The giant Cambrian form Anomalocaris is considered to have been a raptoral predator of trilobites. However, doubt has been raised about its ability to successfully predate on strongly biomineralized forms (durophagy). A specimen of the trilobite Naraoia from the Early Cambrian Emu Bay Shale of South Australia represents the earliest direct body fossil evidence of predation on nonbiomineralized individuals. Analysis of arthropod cuticle rheology and examination of the injuries inflicted on this specimen suggest that Anomalocaris was the predator. It appears that some anomalocaridids actively utilized their large frontal appendages to rapidly flex trilobites during predation. Comparison with predation damage from mineralized trilobites and coprolites suggests that this method of flexing allowed durophagous predation. The presence in the Early Cambrian of durophagous, nonbiomineralized predators may have important implications for the role of predation pressure in the acquisition of mineralized cuticles and the rise of enrollment in trilobites. Variation in the frontal appendages of anomalocaridids indicates that niche partitioning within the genus was well established by the late Early Cambrian. From Pratt: The lower Rabbitkettle Formation of northwestern Canada is a monofacial Upper Cambrian unit of variably calcareous, argillaceous siltstone and fine-grained sandstone with rare bioclastic grainstone, deposited on a gentle slope below fair-weather wave base with no discernible fluctuation in water depth. The trilobite fauna is a mixture of pandemic agnostoids and Lau rentian polymeroids. including protaspides and meraspides, and individuals are disarticulated, non-abraded and mostly oriented convex-upward. Bioclasts are interpreted as in situ elements affected only by weak bottom currents and storm-induced turbulence. A major proportion of the larger (greater than or equal to 5 mm across) polymeroid cranidia and pygidia in the lower parr (Marjuman) of the formation are broken; large thoracic segments are often broken at the axial furrow and some broken free cheeks occur, but essentially no broken agnostoids or hypostomes were observed. Trilobites are not broken in upper beds (Steptoean), above the base of the Glyptagnostus reticulatus Zone. Physical breakage cannot be dismissed entirely, but most damage is interpreted to be due to size-selective predation, possibly through lethal blows similar to those delivered by some extant stomatopod crustaceans. A possible culprit may be an animal akin to Yohoia, known from the Middle Cambrian Burgess Shale. The distribution of attacked trilobites serves as a prosy for the presence and disappearance of soft-bodied carnivores. In the Rabbitkettle Formation, it suggests that Burgess Shale-type animals may have persisted into the Late Cambrian but suffered extinction at the Marjuman-Steptoean 'biomere' event when most trilobite species vanished.