Nautilus and ammonoid model (IMAGE) University of Utah Caption The half-cut shell of the modern Nautilus (right). 3D-printed half-cut ammonite shell (left). Chamber model from the current study, cut to show internal geometry (top). Credit David Peterman Usage Restrictions Credit as indicated License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.