Primarily a business man with one home in Newport, Rhode Island, another in Philadelphia, Samuel Powel was once a member of the Board of Trustees at the University of Pennsylvania and a great friend of Joseph Leidy. As an amateur naturalist he was interested in optics and the invention of a machine for showing microscopic slides directly on a screen. He was elected to the Academy in 1847 and for a short period was its corresponding secretary. The photographs in this collection include 67 fish and 6 pictures of crabs. They are all mounted on cards and are accompanied by a letter to Joseph Leidy, 1865.