Sharks' teeth, shells and bamboo were formerly generally used as cutting instruments for shaving and surgical operations.
This elaborate type of scolex appears to be an adaptation to grasp the spiral intestinal valve of sharks and rays.
Of the cartilaginous fishes, Chondropterygii, the true sharks and hammer-headed sharks, are numerous.
Besides chipped stone knives, the teeth of rodents, sharks, and other animals served an excellent purpose.
Over a large part of the central Pacific, far removed from any possible land-influences or deposits of ooze, the red-clay region is characterized by the occurrence of manganese, which gives the clay a chocolate colour, and manganese nodules are found in vast numbers, along with sharks' teeth and the ear-bones and other bones of whales.