Scanning electron micrograph (SEM) of tooth-like structures from from condonts, known as condont elements. Condonts are extinct prehistoric eel-like animals. For many years the animal was only known from these microfossils that were widely distributed in marine rock. It is thought that a single animal would have many condonts of different shapes. These specimens date to the Silurian (around 444 to 419 million years ago) and were found in Gotland, Sweden. Magnification: x25 when printed at 10 centimetres wide.