No. 2.] THE RELATIONS OF PROTOCERAS. 339 



is shaped more as in Moschus. The radial facet consists of an 

 anterior convexity, which is lower than in Oreodon, and not 

 reflected so far over upon the dorsal face of the bone as it is 

 in that genus, and of a posterior concavity. In the tragulines 

 the scaphoid is relatively much narrower and the anterior con- 

 vexity for the radius much higher and rising steeply toward 

 the ulnar side, while the inner side is excavated for a descend- 

 ing process of the radius. The proximal surface of the 

 scaphoid is thus much more like that of Mosclms than of the 

 tragulines and differs markedly from that of Oreodon in the 

 sudden narrowing or excavation which invades the posterior con- 

 cavity from the ulnar side of the bone. The distal end is very 

 different from that seen in any of the groups mentioned above ; 

 it is occupied by two distinctly separated facets, for the trape- 

 zoid and magnum respectively. The former is rather the 

 smaller of the two and is simply concave and of irregularly 

 oval shape. The magnum facet stands at a somewhat lower 

 level than that for the trapezoid and is nearly flat in front, 

 becoming concave posteriorly to receive the head of the mag- 

 num. There is no distinct facet for the trapezium, though 

 Osborn and Wortman state that the two bones are in contact. 

 On the ulnar side are two facets for the lunar, one proximal 

 and one distal, and both nearer to the dorsal than to the pal- 

 mar border. The distal facets on the scaphoid of Oreodon are 

 entirely different from those of Protoceras both in shape and 

 in position, which is due to the fact that in the former the 

 magnum has shifted almost entirely beneath the scaphoid, 

 while the lunar has gone over upon the unciform. In the 

 Pecora and Tragulina these facets are changed by the coales- 

 cence of the magnum and trapezoid, and in the latter group, 

 by a displacement similar to that which has occurred among 

 the oreodonts. In PoebrotJieriimi, on the other hand, we find 

 a condition very like that of Protoceras, with the addition of a 

 minute facet for the trapezium. 



The lunar is remarkably high and narrow, narrower even 

 than the scaphoid, which is the reverse of the proportions 

 found in Mosclms and Tragnliis, though in DorcatJieriiim {Hycc- 

 moschus) the lunar is the narrower of the two. The proximal 



