A sea biscuit shell is the hard exoskeleton of a sea biscuit, an ancient echinoderm related to sand dollars and sea urchins. These shells, often found as fossils, reveal much about the structure and function of sea biscuits in marine ecosystems. By understanding the structure and role of sea biscuit shells, we can appreciate their significance in both ancient and modern marine environments. Discover the unique features of sea biscuit shells and their contribution to the marine food web. Embrace the complexity and importance of sea biscuit shells and their role in maintaining healthy marine ecosystems.