The Yale Peabody Museum's collection of invertebrate fossils is one of largest in the United States, in volume and in geographic, stratigraphic and taxonomic representation. The holdings of the Division of Invertebrate Paleontology represent more than 350,000 specimen lots, approximately 4 million individuals. A total of 35,000 are type specimens; about 4,500 are the basis of new species descriptions. Over 300,000 specimen lots are available in the online specimen index; all known type specimens are included.