The author describes a find of a Micraster, an irregular echnoid with a heartshaped test and often a granular surface. The ambulacral areas are sunken and form a five flower pental shape; between these are narrow plates. The Micraster is found in Zuidwolde (Drenthe). It's a fossil kernel of light grey flint with a weight of 35 grammes and a lenght o f41 millmetres. The author gives also a biological supervision of sea-urchins in general and shows some photos of other fossils in flint.