Shape of Life: Mollusc Animation: Nautilus Body Plan

Numerous tentacles, a funnel that evolved from the foot, a mantle that secretes the shell, and a pair of jaws with a radula- these all clearly show the nautilus mollusc design. Spiraling through the shell, a tube called the siphuncle removes the water in the chambers so the nautilus can maintain its buoyancy. [2:35]