LOUISE K. BROMAN / SCIENCE PHOTO LIBRARY LOUISE K. BROMAN / SCIENCE PHOTO LIBRARY
Nautilus shell. Section through the shell of a nautilus (Nautilus sp.). The animal itself has been removed, allowing the nacreous (mother of pearl) inner chambers and spiral structure to be seen. The nautilus is a marine cephalopod related to the squids. The animal lives in the last and largest chamber of its shell, and is connected to the rest of it by a long tube called the siphuncle (not seen). It can regulate its buoyancy by using its siphuncle to vary the gas-liquid ratio in the smaller chambers. As the animal grows, new chambers are added. Nautiluses live in the warm Australasian seas, and use their tentacles to capture crustaceans from the sea bed at night.
Model release not required. Property release not required.