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11 

 UINTA SELENODONTS 



the magnum is relatively larger than in Camdomeryx and has a proportion- 

 ately larger scaphoid surface, though that for the lunar is still well developed, 

 and the distal surface for the third metacarpal is much more strongly convex 

 in the transverse direction. 



The unciform is relatively small, hardly exceeding the scaphoid and 

 pyramidal in size, though in the vertical dimension it, like the other distal 

 elements, considerably exceeds the corresponding bone of Leptomcryx. The 

 lunar facet is small and oblique in position and makes an obtuse angle with 

 the surface for the pyramidal, which is altogether proximal. Quite a large 

 facet for the unciform process of the third metacarpal occupies the distal half 

 of the radial side and almost meets the lunar facet, leaving between them 

 only a very narrow area, which may come into contact with the magnum. 

 The distal end is but slightly convex, and the facets for the fourth and fifth 

 metacarpals lie in almost the same transverse plane. In Leptomcryx the unci- 

 form is broader and much lower; its surface for the lunar is more proximal in 

 position and its connection with the third metacarpal is considerably reduced. 

 In Protylopus the unciform is larger in every dimension than in Camdomeryx. 

 The proportions of its various facets are not markedly different from those of 

 the latter, except that the surface for the fourth metacarpal has somewhat 

 increased at the expense of that for the fifth. 



In the specimen before us the metacarpus has preserved but four mem- 

 bers, but there is some reason to believe that five were present in the animal, 

 though doubtless the pollex was in a rudimentary condition. The median 

 pair of metacarpals are but moderately enlarged, while the lateral pair are but 

 slightly reduced, giving to the manus an almost isodactyl appearance. The 

 laterals are relatively little heavier, though decidedly longer than those of 

 Leptorcodon, and are, consequently, much less reduced than those of Protylopus. 

 In spite of its primitive appearance the manus of Camdomeryx bears a dis- 

 tinct resemblance to that of Leptomeryx, although in the latter the lateral 

 metacarpals are very slender and almost splint-like. Metacarpal ii. is quite 

 long and stout, though shorter and more slender than the median pair; the 

 proximal end is not enlarged, except slightly in the dorso-palmar dimension, 

 its breadth not exceeding that of the shaft, and it bears a narrow, plane facet 

 for the trapezoid and a very minute one for the magnum. On the radial side 

 the head is flattened and slightly excavated, doubtless for the reception of 

 the rudimentary first metacarpal. For most of its length the shaft is closely 

 applied to that of mc. iii., and is of uniform size and trihedral shape ; its 



