338 SCOTT. [Vol. XI. 



facet is not sharply defined by a prominent ridge from that of 

 the lunar, as it is in Cariactis, Leptovieryx, and Tragulus, the 

 two articular surfaces being quite continuous in front " (No. 8, 

 p. 360). In the adult female skeleton which we have been 

 considering, the process of bone bearing the scaphoid facet is 

 produced backward more than in Tragidus and almost as 

 much as in Moschus, though the lunar does not abut against 

 the ulnar side of the process so extensively as in that genus. 

 The scaphoid facet is distinctly divided from that for the lunar 

 by a ridge which is prominent even in front, though much less 

 so than in the modern ruminants ; it is concave in front and 

 convex behind. The lunar facet is rather narrower than the 

 scaphoidal and is of similar shape, but the posterior convexity 

 is much less extended toward the palmar side. The straight 

 course taken by the facets, to which Osborn and Wortman 

 have called attention, is a difference from all the modern selen- 

 odonts, and even in such ancient forms as Anoplotheriimi and 

 Lcptomeryx the facets run obliquely from before backward and 

 inward. In the camels this obliquity is not very marked. In 

 another respect Protoceras differs from all the existing Pecora, 

 Tylopoda, and Tragulina, viz., in the absence of any facet on 

 the radius for the cuneiform. 



The manus has already been well described by Osborn and 

 Wortman, but for our present purpose it will be necessary to 

 examine it somewhat more in detail. 



The Carpus (PI. XXII, Fig. 17) is remarkably primitive, as 

 compared with the great degree of modernization displayed in 

 the skull. Schlosser (No. 9) long ago called attention to the 

 fact that a constant difference between the more ancient and 

 the later artiodactyls was to be found in the much greater 

 relative height (vertically) of the carpus in the former, espe- 

 cially with regard to the distal elements. This ancient feature 

 is as decidedly marked in Protoceras as in the oreodonts. In 

 the shapes of the individual bones, on the other hand, may be 

 seen some approximation to modern conditions. The scaphoid 

 is high, but not much extended transversely or antero-poste- 

 riorly. Its shape is thus entirely different from the almost 

 cubical scaphoid of Oreodoti, and though considerably higher, it 



