Herewith is sent a copy of the medallion which commemorates the fiftieth anniversary of the Academy. It was designed by the sculptor Leonard Crunelle, of Chicago. The obverse bears the figure of Minerva with a motto from Lucretius- Naturae species ratioque. The reverse bears the portraits of six leading members of the Academy during the half century. Thomas C. Chamberlin (1845-...) Geologist; Professor, Beloit College; State Geologist, Wisconsin; President, University of Wisconsin; now Professor, University of Chicago. Increase A. Lapham (1811-1875), of Milwaukee. Surveyor, naturalist, geologist; State Geologist, Wisconsin, 1873-75. George W. Peckham (1845-1914), of Milwaukee. Teacher, Librarian, Zoologist. Roland D. Irving (1847-1888), of Madison. Geologist; Professor, University of Wisconsin; Geologist, Wisconson and United States Geological Surveys. William F. Allen (1830-1889), of Madison. Historian, Professor of Latin and History, University of Wisconsin. Philo R. Hoy (1816-1892), of Racine. Physician, Naturalist. All of these men contributed largely to the success of the Academy; five were among its founders; each served as its president except Dr. Lapham, who was its first secretary and acted in that capacity until his death. An account of the medallion and sketches of the lives of the six members will appear in Vol. XX of the Transactions of the Academy, now in press.