408 THE MAMMALIA OF THE UINTA FORMATION. 



The metacarjmls are but scantily represented in the collection, and only one of 

 these exhibits the proximal end. Fortunately, however, this is the first metacarpal 

 or pollex, the existence of which would naturally be infeired from its presence in 

 Oreodon. There can no longer be any question as to the pentadaetyl character of the 

 fore foot in Oreodojt, as two specimens of O. Culbertsoni, Colorado and Dakota, with 

 the pollex in position, are preserved in the Princeton Museum, and in the Museum of 

 Comparative Zoology there is a beautifully preserved manus of 0. gracilis in 

 which all five digits lie in their natui-al position in the matrix. In Protoreodon the 

 first metacarpal is proportionately better developed, being both stouter and longer, 

 than in Oreodon. Its proximal end has a nearly flat head for articulation with the 

 trapezium. In none of the specimens of Oreodon mentioned have any phalanges 

 been found in connection with mc. i, though the distal end is rounded and fiiintly 

 keeled on the palmar side, indicating the probable existence of phalanges. Such 

 were certainly present in Protoreodon, as is shown by a small proximal phalanx be- 

 longing to the pollex. Its proximal facet is very oblique, sloping strongly outwards, 

 and is but slightly concave. Its distal surface plainly shows the articulation for the 

 ungual. The pollex, though of small size, was thus present in all its parts, and the 

 importance of this fact as connecting the aitiodact} Is with the always pentadaetyl 

 Condylarthra is obvious. It seems almost certain that artiodactyls with unreduced 

 anterior feet existed through the Bridger and Wasatch periods, though it is some- 

 what surprising to find them persisting so late as the White River Miocene. 



The ])elvis is not well preserved in any of the specimens. Several fragments 

 seem to show that in construction it is essentially like that of Oreodon, and therefore 

 rather suilline in character. The ilium has a long compressed peduncle which expands 

 rather abruptly into a large terminal plate for articulation with the sacrum. There 

 is no supra-acetabular fossa. The length of the ischium could not be ascertained. 



The femur would seem to be longer and stouter proportionately than in Oreo- 

 don. The rotular trochlea is very prominent and quite narrow, and has the inner edge 

 higher than the outer. A difference from Oreodon is shown in the presence of a fossa 

 for the plantaris muscle instead of a rugose sui'face, though, as Kowalevsky has 

 shown, no great importance can be attached to this character. 



The tibia is only imperfectly represented ; some points may, however, be made 

 out with regard to it. It is entirely unankylosed with any portion of the fibula, and 

 has a stout shaft of transversely oval section below, above it is more trihedi-al. The 

 distal end is very like that of Oreodon, with deeply incised grooves for the astragalus 

 and a very well-developed malleolai- process. 



The ^.bula is entire but very slender. Its distal end is closely applied to the 



