Cope. Other portions of jaws and horns appear to belong to Cosoryx 

 furcatus Leidy, and C. necafus Leidy. In one place I discovered a 

 nearly complete sknll, and a complete mandible of a Cosoryx which I 

 believe to be a new species. These were associated with a manus and 

 pes, lacking part of the phalanges, a radius and ulna, part of pelvis, 

 three lumber, one sacral and three dorsal vertebrae, portions of ribs 

 and other fragments. The animal w;is young and probably not quite 

 lull grown. , 



In the skull both zygomatic arches are broken off and the upper 

 part of the face is injured anterior to the orbits. The animal was 

 jirobably a. female, as there are no signs of horns. 



The last upper molar had recently protruded and had not yet 

 reached the height of the others. On the left side the three tem- 

 1 orary molars had recently been shed and the three permanent ones 

 were all just protruding. The last premolar, which was double, like 

 the true molars, was shed but caught between the upper and lower 

 teeth, from which I removed it. On the right side only the first milk 

 pi-emolar is shed. The next one (premolar 3) is more triangular than 

 Ihe last temporary premolar or the permanent molars; the antero-in- 

 terior lobe not being so well de^^'eloped. The pei-nlanent premolars 

 liave each one external and one internal crest. In premolar 3 a limb 

 runs outward and backward from the inside of the internal crescent. 



The molars are long vertically like those of Antilocapra. The an- 

 terior liorns of the external crescent do not pi'oject quite so strongly 

 luit the median rib of the antero-external crescent is very much more 

 prominent, and is large in proportion to the size of the tooth. The 

 orbit is lower than in Antilocapra and is placed farther forward, the 

 anterior border being above the posterior part of the second molar. 

 A ridge begins at the antero-inferior border of the orbit, and extends 

 forward branching al>ove the first molai-— one branch descending and 

 d:^ing out above premolar 3, the other extending forward to the mental 

 foramen which is just in front of a line passing upward from premolar 

 2. Above this ridge in front of the eye is a concavity. 



The facial vacuities were large and occupy about the same position 

 as in Antilocapra In the center of the forehead between the front 

 parts of the orbits is a depression situated somewhat farther forward 

 than the corresponding one in the prong Imck. Back of this the shape 

 of the skull is very different in the two animals. In Cosoryx, instead ot 

 a broad transverse ridge which connects the horns, in the former there 

 is a high center sloping gently fore and aft, and slightly less so later- 

 ally. Above the orbit where the broad rims, wliich form the root 

 of the orbit connect with the other part of the skull, are two ellip- 

 tical depressions extending in the direction of the long axis of the skull. 

 In the posterior part of these depressions open the siipra-orbital fora- 



