Fish scales. Polarised light micrograph the skin of a common sole fish (Solea vulgaris), showing the placoid protective scales. These scales are found under the epidermis, and are made of bone-like dentine. The scales overlap one another, and the ones shown here have radiating bony spines at their outer edges, a characteristic of the fish the scales are from. Magnification: x5 when printed at 10 centimetres wide.