Nautilus Shell Hydrostatics

Abstract

In 1897, Arthur Willey remarked that "there is one thing the Nautilus cannot do, namely, turn upside down" (Willey, 1897a, p. 146). The high degree of hydrostatic stability noted by Willey is a direct consequence of the geometry of the Nautilus shell, and it raises two questions: (1) Which physical parameters contribute to this stability? (2) How do these factors vary among different species of Nautilus? In paleontology, there are two approaches to the study of functional morphology: the empirical approach and the paradigmatic approach. The empirical approach entails observation of organisms actually performing a function and correlation of success of that function with specific morphological features.