538 THE MAMMALIA OF THE UINTA FORMATION. 



astrajT^alus has quite a broad cuboidal facet. The striking difference 

 in the pes of these two genera bears directly upon the question of the taxonomic 

 vahie to be attached to these articulations. 



Other features of the feet are the intei-locking tibio-astragalar joint, the probable 

 presence of a tibiale, the centrale in the carpus, the reduction of mts. i and v in the pes. 



2. Amblypoda. 



Cope has described the feet in this order as " plantigrade" (" Tertiary Yertebrata," 

 p. 507). This term, which has also been generally applied to the proboscidian feet, 

 should now be restricted to the types in which the entire foot rests on the gi'oiind. 

 The Puerco PantolamMa* was probably plantigrade. The position of the meta- 

 podials in the Pantodonta and Dinocerata as indicated in the figures of Marsh 

 (" Diuocerata," p. 184) was analogous, the wrist and ankle joints in each being well 

 raised from the ground. Oiu- own study of the tarsals of Coryphodon has, however, 

 convinced us that the pes was almost plantigrade, while the manus was semi-planti- 

 grade. 



The metacarpals ii and iii are displaced, alternating upon the magnum and unci- 

 form. The intercai-pal displacement is unique ; the lunar has a broad foothold upon 

 the unciform, while the scaphoid has either no magnum facet {Cory pi odon, fide Co-^o) 

 or rests by a considerable posterior facet upon the magnumf as in some species of 

 Uintathenum. The cuneiform rests partly upon mc. v. 



In the tarsus Baur called attention to the fiicet probably for the tibiale upon 

 the astragalus of CorypIiodonX and Uintatlierium. The displacement is extreme, the 

 astragalus extending the entire breadth of the foot in front, covering both the navicu- 

 lar and three-fourths of the cuboid. The astragalar foramen is frequently present in 

 Corypiltodoii (see Cope, loc. cit.) and in Uintatlierium (see Marsh, "Dinocerata," p. 148). 

 The calcaneum has the primitive ectal and sustentacular facets, and the fibula occa- 

 sionally came in contact with it {Uintatlierium, Marsh, oj). cit. p. 152). The meta- 

 tarsal articulation is of the " I'everse" tyi)e, mts. ii and iv articulating laterally with 

 the ectocuneiform. The Amblypoda with unreduced digits, very short spreading 



* riiiccd by Copt; in the Auililypocla. 



f III his Uefinition of the Amblypoda, Prof. Copi; says (" Tcrliary Vortcbrata," p. 378) : "Scaphoid supporlcd liy 

 trapezoid and not by magnum, wliicli willi uncilorm sujiiiorls tlic lunar." Sec also, Amer. Naturalist, Ni>v., 1884, 

 p. 1110. While this definition may ajjjdy strietly to Coryphodon, it cannot to Uintatlierium. Of three carpal series in 

 the I'rincclon Museum, two show a broad scaphoid facet uiion the jiosterior half of the magnum, the third has none 

 In Marsh's " Dinocerata," the lithoirrajihic figure on Plate LIV is incorrect ; the wood-cut, Fig. 153, is approximately 

 correct ; the scajiho-magnum facet is not indii-alcd in Fig. 111?, lint is well shown in Plate XXXIV. Fig. 5, see page 113. 



^ Cope, however, seiianiles Coryphodon by the ab.sence of a tibiale, from Bathmodon, in which it is present. 



