Members who have not as yet sent their photographs to the Society will confer a favor by so doing; cabinet size preferred. It is requested that all correspondence be addressed TO THE SECRETARIES OF THE AMERICAN PHILOSOPHICAL SOCIETY 104 SOUTH FIFTH STREET PHILADELPHIA, U. S. A. APR 18 1922 LIUKAWY ENTELODONTS FROM THE BIG BADLANDS OF SOUTH DAKOTA IN THE GEOLOGICAL MUSEUM OF PRINCETON UNIVERSITY. INVESTIGATION AIDED BY A GRANT FROM THE MARSH FUND OF THE BY WILLIAM J. SINCLAIR. (Read April 22, 1921.) I had always assumed that entelodonts were rare fossils in the White River Oligocene until last summer when the Princeton Expedition to South Dakota, within an area of about two square miles in the valley of Indian Creek, in Pennington County, between July 14 and 27, collected five skulls and two lower jaws belonging to three species of Archæotherium and noted, but refrained from collecting, perhaps as many more fragmentary specimens within the same area. This mass of new material made it desirable to restudy the Princeton entelodont collection as a whole, as much of it had never been adequately determined. Fortunately, the timely appearance of Mr. Troxell's1 excellent paper on the entelodonts in the Marsh collection at Yale greatly facilitated these studies. Whether certain of the characters used in the classification of these animals are of specific importance or of the nature of secondary sexual structures can not yet be determined. For the present it is safer to give a separate specific name to each well-defined variant, based on adequate material, than to group together forms which may have been rapidly mutating and thereby developing differences of the first degree of importance for detailed faunal and stratigraphic studies. A review of the genera and species represented follows. 1 Am. Jour. Sci., Vol. L., Nov.-Dec., 1920, pp. 243-255, 361-386, 431-445. PROC. AMER. PHIL. SOC., VOL. LX., EE, MARCH 17, 1922. I. FROM THE TITANOTHERIUM BEDS. Archæotherium scotti sp. nov. In 1895 Professor Scott2 announced the discovery of the classic specimen now known as No. 10885 and mounted in the Geological Museum of Princeton University. This almost complete and unique skeleton (not "two almost complete skeletons" as mistakenly stated in the preliminary report) was found in the summer of 1894 by Mr. H. F. Wells in the upper Titanotherium beds in Corral Draw, South Dakota (whether in Pennington or Washington Counties does not appear), was secured by Mr. J. B. Hatcher and excavated by him. May 11, 1894, and was referred by Professor Scott, in his announcement to the International Zoological Congress at Leyden, to Leidy's FIG. 1. Archæotherium scotti sp. nov. Holotype, No. 10885. Three-quarter view of the skull and jaws from the left side, in the position in which it stands on the mounted skeleton, approximately one-sixth natural size. Drawn from photograph and the specimen. 2 W. B. Scott, "Compte-Rendu des Séances du Troisième Congrès International de Zoologie," Leyde, 16-21 Septembre, 1895. Leyde, E. J. Brill, 1896. |