DAKOTA AND NEBRASKA. 173 



ANTILOPID^. 

 COSORYX. 



COSORTX FURCATITS. 



A small ruminant animal, apparently intermediate in character to the family of 

 the Deer and that of the Antelope, is indicated by several fossils obtained by Dr. 

 Hayden on the Niobrara River, Nebraska. The specimens are portions of several 

 antlers, or perhaps horn cores, of which the better preserved one is represented in 

 figure 8, plate, XXVIII, of the natural size. It bears a resemblance to a similar but 

 larger fossil described by Gervais in the Zoologie et Pal^ontologie Francaises, page 

 78, and represented in figure 4, plate xxiii, of that work. Gervais refers the fossil to 

 a species with the name of Antilope dichotoma, but it is more probable that all the 

 fossils noticed represent a genus differing from either Antilope or Gervus. The fossils 

 have no burr or crown at the base as in the latter, and .they bifurcate at the upper 

 extremity, which is not the case in any known Antelope, not even in the Prong Horn, 

 Antilocapra americana, in which the foi'king of the horn does not extend to its core. 



The fossil, as represented in our figure, is about two and a half inches long from 

 the fragment of the frontal bone to the broken ends of the prongs above. The shaft 

 is straight and cylindroid, and only slightly striated longitudinally. In the second 

 specimen the shaft is more cylindrical than in the former. The upper extremity 

 becomes gradually more flattened and expanded, and divides, as already intimated, 

 into a pair of prongs. 



