» This article's about the skeletal structure. See also Spicule (solar physics) and Spicule (glass manufacture).Spicules are tiny spike-like structures of diverse origin and function found in many organisms, such as the copulatory spicules of certain nematodes or the grains on the skin of some frogs. This article discusses the skeletal spicules that occur in most sponges. They provide structural support and deter predators. Large spicules, visible to the naked eye are referred to as megascleres… (More on Spicule)