Peterson : A New Titanotherr from the Uinta Eocene, 45 



Fig. 10. Diploceras 

 osborni Peterson. (Pa- 

 ratype. No. 2860.) X \. 

 Pisiform. i, superior 

 view; 2, lateral view. 



The forefoot of Xo. 2860 is represented by the scai)hoid, pisiform, 

 trapezoid, Mc. II, IV, and V, and one or two phalanges. No. 2859 

 has also Mc. IV and V represented. 



As might be anticipated from the description of the limb, it is 

 found that the foot is higher than in T. validum of the Oligocene. 

 Thus the scaphoid is higher in proportion, and 

 narrower than in the latter species, but is of 

 considerable fore-and-aft diameter. In detail 

 there are only such differences as one might 

 expect from the general outlines described, i. e., 

 the different articulating surfaces of the distal 

 face are narrow and long, while the articula- 

 tion for the radius is less concave antero-pos- 

 teriorly than in the Oligocene form. The 

 pisiform has a similar long attenuated shaft ter- 

 minating in an obtuse tuberosity of considerable 

 vertical diameter, but transversely rather thin. 



Besides the greater height of the trapezoid, the small posterior supe- 

 rior facet for the magnum, which is characteristic of TitanotJiermm, is 

 practically wanting in the present form. Judg- 

 ing from the facet on the postero-radial angle 

 there is present in the new Uinta genus a trape- 

 zium of considerably larger size. 



Mc. II is long, quite broad, but of small an- 

 tero-posterior diameter, which is in part due to 

 crushing. The proximal end is partly broken 

 off, so that the different facets cannot be ac- 

 curately compared. The shaft is of quite uni- 

 form width until the distal articulating surface 

 Fig. ir. Diploceras jg reached, where there is on the radial face 



osborni Peterson. (Pa- 11 . t-i • 1 ^ • 1 



a sudden expansion. 1 his character is less ap- 

 ratype. No. 2860.) X i. . • ,u rM- r j i 



Dorsal view of manus. P''^^"^ '" ^^^ Oligocene forms and also appa- 

 rently less than in the metacarpus of the 

 Princeton specimen from the Uinta, as figured by Scott and Osborn. 

 Mc. IV is, as stated, represented by fragments in both type and 

 paratype, and displays no features of especial importance. 



Mc. V is longer and slenderer than the same element in T. validum 

 and that referred to Diplacodon (I. c, PI. IX, Fig. 13). Proximally 

 and dista ly the bone is expanded much as in Titanotherinm, and the 



