Joseph Leidy (1823 – 1891) 

Leidy was professor of anatomy at the University of Pennsylvania, and later was a professor of natural history at Swarthmore College. His book Extinct Fauna of Dakota and Nebraska (1869) contained many species not previously described and many previously unknown on the North American continent. At the time, scientific investigation was largely the province of wealthy amateurs.

Leidy was also a renowned parasitologist, and determined as early as 1846 that trichinosis was caused by a parasite in undercooked meat. He was also a pioneering protozoologist, publishing Freshwater Rhizopods of North America in 1879 – a masterpiece that is still referenced today.
Leidy collected gems as well as fossils, and donated his important collection of the former to the Smithsonian before he died. At Swarthmore, he also taught a class on mineralogy and geology.