The mollusk collection has been part of Carnegie Museum since it began in 1896, starting with the collection of George Clapp (honorary curator of malacology at Carnegie Museum). The current collection contains more than 150,000 lots (1.3 million specimens) from marine, freshwater, and land environments, from the mid-1800s to present, representing 6 of the 7 classes of mollusks, and with holdings from every continent and ocean, mostly from North America (75% of collection) and Europe (13% of collection). Taxonomic strengths are freshwater mussels (Unionoida) of North and South America (including the important collection of Arnold Ortmann, who literally wrote the book on North American Unionoida); terrestrial gastropods of North America, especially minute species (more specimens of the tiny Punctum minutissimum than all other museums combined) with the world’s largest collection of land snails from northern Appalachia; and the world’s largest collection of freshwater pill clams (Sphaeriidae, primarily from Victor Sterki and including more than 1000 type lots, still being cataloged). Many of our historical specimens of freshwater and terrestrial mollusks have some of the most detailed locality information compared to other museums. The specimen collection currently ranks 11th largest in USA. The current section head’s (curator of collections) expertise is land snails of North America.