Interacting Constraints and the Problem of Similarity in Gastropod Structure and Function^*

Gastropods have served as research subjects for investigating questions that transcend both the taxon and the field of malacology. A major set of questions arises from repeated patterns in the microstructure, sculptural features, and coiling geometry of gastropod shells. The problem of similarity is one of distinguishing among alternative explanations of repetition and close resemblances. What explains the repetition of structural features? Are...