I liked Wes Thorsson's notes on rarity. I'd just like to point out that virtually any species is "rare" at the edges of its distribution. There, even the collection of a few specimens could conceivably damage the local population. The more collectors know about shells before they collect (including their natural distribution), the better. As to the word "rare", in botanical Latin it meant "sparse", hence "sparsely distributed", hence "uncommon". For example, a tree with widely spaced branches might be said to have "rare" branches. We have some rare birds in Conch-L. Andrew K. Rindsberg Geological Survey of Alabama