Historical reference: Do not rely on this information. It is very old. About this collection
Scales, horny modifications of the skin in reptiles, on the legs of birds, and in some mammals. The scales of fishes are developed in grooves or pockets of the skin, as are the hair, and feathers of higher animals. In the Sharks and Rays scales are replaced by "skin-teeth," consisting of a horny base covered with enamel.