The collection contains primary types of nine species and secondary types of 5 species. The collection contains over 91,000 specimens and 12,100 lots of approximately 350 species in 30 families. Almost all are from North America. About 50% of the collection is from Illinois; the remainder is mostly from the southeastern United States. The best represented groups are crayfishes, shrimps, scuds, slaters, and pill bugs. A few lots of marine crustaceans found along the North American coastline are also present in the collection.