Malacology, the study of mollusks, has been part of the Academy since its founding in 1812. Thomas Say (1787-1834), Isaac Lea (1792-1886), Samuel S. Haldemann (1812-1880), George W. Tryon, Jr. (1838-1888), Henry A. Pilsbry (1862-1957), H. B. Baker (1889-1971), and R. Tucker Abbott are some of the more notable malacologists associated with the Academy.

The collection of recent mollusks at The Academy of Natural Sciences of Philadelphia (ANSP) is the oldest in the country, and the second largest catalogued one in the world. It currently has more than 430,000 catalogued lots containing about 10 million specimens, including 30,000-35,000 lots preserved in ethanol. Type specimens of more than 400 authors are represented in more than 12,000 type lots. ANSP has specimens from all over the world. Greatest strengths are in shallow-water marine mollusks from the tropical Indo-Pacific and the Western Atlantic and worldwide freshwater and land mollusks.

Bursa Iamarckii