74 BULLETIN OF THE 



surface has not the simply convex shape seen in Oreodon, but rises high towards 

 the ulnar side, and is much depressed on the radial. The distal surface is occu- 

 pied by the long concave and obliquely placed facet fur the unciform, that for 

 the magnum being altogether lateral. This is the culmination of a tendency 

 already noticeable in 1' rotoreodon of the Uinta formation, the earliest known 

 member of the family, and more marked in Ureodon, namely, the movement of 

 the magnum away from the lunar and under the scaphoid. In Merycochoerus 

 (and Merychijus) the lunar does not rest upon the magnum at all, touching it 

 t)nly laterally. Tlie cuneiform is much like that of Oreodon. The pisiform 

 is very different from that seen in the earlier genera of the family, and shows a 

 tendency to assume the form characteristic of the pigs, though relatively much 

 larger than in those animals. Compared with that of Oreodon, it is shorter, 

 heavier, and especially much more exi)anded at the free end. No trapezium 

 is preserved in connection with this specimen, and as no facets for it are clearly 

 distinguishable on the other carpals, it may not have been developed. The 

 trapezoid is very different from that of Oreodon, in being very much higher, nar- 

 rower, and deeper; the facet for the scaphoid is obli([ue and almost as much 

 posterior as superior ; behind, the bone is drawn out into a projecting process, 

 not abruptly truncated by the facet for the trajjezium, as it is in Sus. The sig- 

 nificant characters of the trapezoid are shown by the distal surface, which is 

 constituted as in the pigs, having a large facet for mc. II. and a small one for 

 mc. III. ; in the pig the two facets are of nearly the same size. The magnum 

 is very peculiar ; as Cope has shown, it lies entirely Ijeneath the scajilioid and 

 internal to the lunar ; its proximal surface is occupied by a large, sli-htly con- 

 vex facet for the scaphoid, very different in shape from the same fticet in Oreo- 

 don, as it lacks the abruptly rounded posterior rising ; the ulnar side is even 

 more deeply concave than in Merychyits, encircling the convex lunar. The 

 unciform differs but little from that of Oreodon, except that the proportions of 

 the proximal facets have changed, that for the lunar being considerably the 

 larger. 



The metacarpals are relatively much shorter and broader than in Oreodon, 

 the lateral digits are somewhat reduced, though not very much, while the me- 

 dian ones have greatly increased in thickness. In proportions the metacarpus 

 is quite like that of Sus, though as in all the oreodonts the keels of the distal 

 trochleee are confined to the palmar surface. Mc. II. is short, stout, and com- 

 pressed ; it articulates by a narrow surface with the trapezoid, but is excluded 

 from the magnum. Mc. III. is very suilline in appearance, but its proximal 

 end is not much extended transversely ; on each side of the magnum surface is 

 a facet for the trapezoid and unciform, the latter considerably the larger, while 

 in the pig they are of nearly equal size. Mc. IV. is of about the same breadth 

 and thickness as mc. III.; its proximal end is transverse, as in the pig, not 

 oblique, as in Oreodon. Mc. V. is not preserved in the specimen, but the facet 

 for it on the unciform shows that its head was flatter than in Oreodon, and that 

 it did not rise so much upon the external side of the unciform. 



The phalanges resemble those of Oreodon, except for their greater stoutness. 



