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21 



WHITE RIVER SELENODONTS 



num are separate, and the carpal elements, especially those of the proximal 

 row, are high vertically. The metacarpus has four members, of which the 

 laterals are still well developed, much better than in Leptomeryx. 



The hind-limb is considerably longer and stouter than the fore-limb. 

 The pelvis is like that of Poebrotherium and Leptomeryx, and the femur is a 

 good deal like that of the former, but is shorter and heavier, its rotular 

 trochlea is broader, and the suprapatellar fossa less distinct. The tibia is long 

 and the fibula completely reduced, its proximal end a short spine anchylosed 

 with the tibia and its distal end a malleolar bone. The cuboid and navicu- 

 lar are separate, as are the metatarsals. The latter are reduced to two 

 functional members, while the lateral pair are reduced to splints. The pha- 

 langes are like those of Poebrotherium, though rather shorter and heavier. 



Aside from the extraordinary peculiarities of the skull, especially in the 

 male sex, Protoceras displays an unmistakable likeness to Leptomeryx and 

 Hypertragulus, a. likeness which is apparent in the vertebral column, the 

 limb-bones, the feet, and the dentition. Combined with these are certain 

 resemblances to Poebrotherium, fewer and less striking ones to the oreodonts, 

 and a number to the Pecora. It should be remembered, however, that the 

 pecoran characteristics, which are almost exclusively confined to the skull, are 

 such as are found only in the higher Pecora, the Cavicomia, and do not occur 

 in the deer. It may seem quite absurd to regard Protoceras as an aberrant 

 member of the Tylopoda, but, as will be shown in the sequel, it is highly 

 probable that such is the correct view of its relationships. I am glad to find 

 myself in agreement with Dr. Wortman on this point, for in the paper already 

 cited he speaks of "the early cameloids, Protoceras and Leptomeryx." 

 ('98, p. 102.) 



