Joseph Mellick Leidy (September 9, 1823 – April 30, 1891) was an American paleontologist, parasitologist and anatomist. Leidy was professor of anatomy at the University of Pennsylvania, later was a professor of natural history at Swarthmore College and the director of scientific and educational programs at the Wagner Free Institute of Science. 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. The Leidy Glacier in northwest Greenland was named by Robert Peary after him. Early life and family Joseph Leidy was born on September 9, 1823, to an established Philadelphia family of Pennsylvania Germans. His father, Philip, was a hatter; his mother, Catharine, died during childbirth when he was young. His father then married his wife's first cousin, Christiana Mellick. Leidy also had a brother, Thomas Leidy. With the support of his stepmother and after overcoming the opposition of his father, who wanted him to be a sign painter, Leidy studied medicine at the University of Pennsylvania. He graduated with his medical degree in 1844. He married Anna Harden, a woman who took a serious interest in his work and helped him with it on occasion. Their marriage was childless, and they eventually adopted an orphaned seven-year-old girl, Alwinia, daughter of the late Professor Franks of the University of Pennsylvania. In 1848, he was elected a member of the American Philosophical Society. Paleontology Leidy named the holotype specimen of Hadrosaurus foulkii, which was recovered from the marl pits of Haddonfield, New Jersey. It was notable for being the first nearly complete fossilized skeleton of a dinosaur ever recovered. The specimen was originally discovered by William Parker Foulke. Leidy concluded, contrary to the view prevailing at the time, that this dinosaur could adopt a bipedal posture. He also described the holotype specimens of Arctodus (A. pristinus), the dire wolf (Aenocyon dirus), and the American lion (Panthera atrox), among many others. Noted American fossil collector and paleontologist E. D. Cope was a student of Leidy's, but the enmity and ruthless competition that developed between him and rival paleontologist O. C. Marsh eventually drove Leidy out of western American vertebrate paleontology, a field that Leidy had helped to found. Marsh claimed Leidy contributed to the falling out of the two by showing Cope in the presence