The _phalanges_ are very short and broad, the lower facets marked by a shallow median groove. The ungual phalanx is wide and short, with a crescentic outline. _Measurements._ M. Third metatarsal, total length ·090 Third metatarsal, transverse diameter, proximal face ·017 Third metatarsal, transverse diameter, distal end ·019 Second phalanx, length ·024 Third phalanx ·014 Total estimated length of manus (6 inches) ·155 Palæosyops vallidens, Cope. Proceedings Am. Phil. Society, 1872, p. 487; Hayden's Survey, 1872, p. 572. _Specific characters._--Founded on details of dental structure. Superior size. In the upper molars two strong transverse ridges connect the inner tubercle with the outer crescents, inclosing a pit between them. In the premolars the outer crescents fuse almost into a single ridge. These united crescents are relatively narrower. The inner molars are also narrower, and the posterior tubercle of the last is an elevated cone. Fragment of a lower jaw containing the two posterior molars. The measurements of the teeth are identical with those given by Professor Cope. The depth of the ramus below the last molar is three and one third inches, and it is slightly heavier below than in _P. major_. _Restoration of Palæosyops._--The elevation of _Palæosyops major_, which is taken as a type, was approximately the same as that of _Palæotherium magnum_ as restored by Cuvier. The nearly complete ilium, femur, tibia, and tarsus of _P. major_ in our possession, enable us to make the following estimate of the elevation of the hind quarters. INCHES. _Pelvis_, height of ilium above acetabulum 9 _Femur_ and _tibia_ by actual measurement, allowing for bend at the knee 26 _Tarsus_, from astragalus, and cuboid 3 _Metatarsus_ and _phalanges_ (estimated from manus of _P. paludosus_) 8 -- 46 It is probable that the fore-shoulders were of the same height. From the atlas, axis, and from other cervicals, several dorso-lumbar vertebræ, and part of the sacrum, a rude estimate places the length of the animal at sixty-seven inches, or nearly six feet, including the head, and excluding the tail.