How big do shells get?
The biggest marine snail is Syrinx aruanus, the Australian Trumpet, at 77.2 cm. (over 30″). The biggest American marine snail, the Horse Conch, Pleuroploca gigantea, is just over 2′. The world’s biggest clam is of course the reknowned Giant Clam of the southwest Pacific, Tridacna gigas. The largest one on record, in the American Museum of Natural History, measures in at almost 55″. (Incidentally, their favored diet is not divers but algae they farm within their own bodies.) These sizes are taken from Wagner and Abbott’s World Size Records, published by American Malacologists and edited by Barbara Haviland of St. Petersburg, Florida.
