Hi Kurt, I don't know what the longest molluscan name is, but Phasianotrochus irisodontes and Pseudostomatella decolorata each have 26 letters, just to give folks something to shoot for. Now, if you included echinoderms, the green sea urchin of our Atlantic coast - Strongylocentrotus droehbachiensis - would win for sure at 33 letters. That's practically an abbreviation though, compared to the crustacean name just given by Tom! Paul M.