Figs. 9 and 10.--Proximal and distal faces of same. Fig. 11.--Proximal end of fibula. Fig. 12.--Right femur, posterior view. Fig. 13.--Trochlea of the same. [Illustration] EXPLANATION OF PLATE III. _Figures one half natural size._ Palæosyops paludosus. Figs. 1 and 2.--Ulna, anterior view, and distal articular face of same. Figs. 3, 4, and 5.--Radius, anterior view; and distal and proximal faces of same. Fig. 6.--Left scapula. Fig. 7.--Right humerus, proximal end, anterior view. Fig. 9.--Left manus, anterior view. Palæosyops major. Fig. 8.--Left humerus, anterior view. [Illustration] EXPLANATION OF PLATE IV. _Figure one half natural size._ Leurocephalus cultridens. Upper and lower jaws. View of right side. Dotted outlines indicate probable position of lower incisor and canine series. [Illustration] EXPLANATION OF PLATE V. _Figure one half natural size._ Palæosyops major. Right innominate bone. The iliac crest and position of pubis estimated in outline. [Illustration] EXPLANATION OF PLATE VI. _Figures one third natural size._ Uintatherium leidianum. Fig. 1.--Cervical vertebra, fifth or sixth, anterior view. Fig. 2.--Dorsal vertebra, anterior region, view of left side. Fig. 3.--Dorsal vertebra, middle region, posterior view. Fig. 4.--Last lumbar vertebra, view of right side. Fig. 5.--Last lumbar vertebra, posterior view. Fig. 6.--Caudal series, first four vertebræ. [Illustration] EXPLANATION OF PLATE VII. _Figures one third natural size._ Uintatherium leidianum. Fig. 1.--Anterior view of right humerus. Fig. 2.--Ulna, side view, length estimated. [Illustration] EXPLANATION OF PLATE VIII. _Figures one third natural size._ Uintatherium leidianum. Fig. 1.---Right scapula. The dotted outline gives an attempted restoration of the original shape. Fig. 2.--Tibia of left side, anterior view. Fig. 3.--View of the proximal articular faces of same. Fig. 4.--Right femur, posterior view. [Illustration] EXPLANATION OF PLATE IX. _Figures four fifths natural size._ Orohippus major. Fig. 1.--Right femur, anterior view, length estimated. Fig. 2.--Right fibula. Fig. 3.--Right tibia, anterior view. Fig. 4.--Calcaneum. Figs. 5 and 6.--Astragalus and navicular. Fig. 7.--Metatarsals and phalanges. Last Fig.--A carnivorous sacrum, probably belonging to the brain, described on pp. 20-22. [Illustration] EXPLANATION OF PLATE X. _Figures 1, 2, 3, 4, and 6, natural size._ Ithygrammodon cameloides. Fig. 1.--Left premaxillary, inner view. Fig. 2.--Left premaxillary, outer view. Fig. 3.--Right maxillary and premaxillary, outer view, premolar, with dotted outline indicating its probable position. Fig. 4.--The premaxillaries in position (probable), view from above, showing size and position of the incisors. Dotted lines indicate the premaxillary spine (estimated).