Dear Brian and Michelle asked me about the nature of the shells that I've scanned recently, and here is a brief explanation along with some other scans... I do not know the exact name for the shells that I've scanned, but they are a species from the phylum "echinodermata" that also includes sea potatoes, sea urchins, sea biscuits (Brian says that mine might also be sea biscuits) and sand dollars as shelled creatures, and sea cucumber and starfish as shell-less species... And know, here comes a sea potatoe (heart urchin)...