Crinoids, also known as sealilies or feather stars, are examples of living fossils. They belong to the phylum Echinodermata, and are distantly related to the starfish, brittle star and sea urchin. Filter feeders, with crowns of pinnules that trap microscopic particles on which to feed, they sway back and forth on the ocean floor. Their fossil remains are found all over the world, but most beautiful and best preserved examples are those from the Posidonia shale beds of Holzmaden in southern Germany. The strong dark colour of the shale matrix serves as a beautiful background to the delicate serpentine neck of the fossil, highlighted by the subtle shimmer of pyritisation. The matrix itself has been prepared, to better the contrast with the superb three-dimensional detail of the fossil itself which stands out in high relief. This specimen remains attached to a piece of flotsam (not all species anchored themselves to the ocean floor, but floated through the oceans attached to drifting floral debris) and gathered around its holdfast are the remains of other members of the colony.