Antifouling is a property of the epidermis in echinoderms. There is neither production of biocides that act at any distance from the surface nor is the sloughing rate of the entire surface capable of explaining the observed antifouling capability. As with many invertebrates, the epidermis in echinoderms is overlain by thin surface coats, often termed the cuticle. The outermost coat has attenuated fibrils radiating outwards from the underlying cuticle. As these fibrils are the “real”; surface of the echinoderm, this is the level at which any antifouling defense must operate. It is suggested that their function is primarily antifouling. The cuticle contains chondroitin sulphate proteoglycan molecules and is negatively charged. The cuticle appears to be a highly extended glycocalyx. It is suggested that the primitive function of cellular glycocalyces is to modulate adhesive interactions at the cell or organismal surface.