large shark jaw

The skeleton of a shark is very different from that of bony fish and terrestrial vertebrates. Sharks and other cartilaginous fish (skates and rays) have skeletons made from rubbery cartilage, a tissue lighter and more flexible than bone.Like its relatives many rays and skates, the shark's jaw is not attached to the cranium. The jaw's surface, which like the vertebrae and gill arches is a skeletal element that needs extra support due to its heavier exposure to physical stress and need for extra strength, has a layer of unique and tiny hexagonal plates called "tesserae", crystal blocks of calcium salts arranged as a mosaic. This gives these areas much of the same strength found in real and much heavier bony tissue. Size about 12x6 inches