Skull

Broadnose sevengill shark
Notorynchus cepedianus

Sharks do not have bones like we do. Instead, they have a skeleton of cartilage hardened by calcium. Employing a CT scanner, Museum paleontologist John Maisey can observe how calcified tissue builds up to form the braincase of a modern shark. Tiny, dense tiles of calcium minerals line the cartilage in order to stiffen it. These tiles are shown in gold in the large image, generated using 3-D density modeling software software. Maisey uses this information to compare braincases of modern and ancient sharks.