120 University of California Publications in Geology [Vol. 9 



approximately parallel sides. In Ilingoceros this groove does not widen 

 distally as much as in Antilocapra, and in both the latter forms the 

 groove is but slightly differentiated from the rest of the inner surface. 

 The surface interior to the articulation with the ventral side of the 

 astragalus is narrow and elongated, very different from Antilocapra, 

 this condition being due to the very marked sloping off of the promi- 

 nence bearing the articulation with the ventral side of the astragalus. 

 Ilingoceros is intermediate in this respect. The shape of the main 

 articular surface for the astragalus is similar to that of Antilocapra, 

 and unlike that of Ilingoceros. The articular surface for the cuboid 

 has not quite so much sigmoid curvature as has Ilingoceros but has 

 considerably more than Antilocapra. The notch in the side of the 

 articulation with the fibula is deeper and sharper than in either of 

 the other genera. There is a well-marked groove just above the articu- 

 lation with the cuboid which is very shallow in Ilingoceros and prac- 

 tically absent in Antilocapra. 



A number of well-preserved proximal and middle phalanges cor- 

 roborate the evidence of the other limb bones, that this species was a 

 very light-limbed form. The narrowness from the inner to the outer 

 side of the proximal phalanges as compared with the anteroposterior 

 diameter is striking. In both Ilingoceros and Antilocapra these dimen- 

 sions have a ration of 5 to 6 at the proximal end, while in Capr ornery x 

 the ratio is 4 to 6. Another characteristic is the great amount of 

 tapering to the point of shortest anteroposterior diameters, the ratio 

 between the narrowest and widest diameters being in Capromeryx 

 1 to 1.76, in Antilocapra 1 to 1.60, and in Ilingoceros 1 to 1.36. A 

 single minute middle phalanx has the same characteristic compressed 

 appearance. The anterior surface just back of the distal articulating 

 surface comes to a distinct ridge instead of being broadly rounded. 

 This portion of the phalanx sags down so as to give a distinct dip in 

 the anterior contour. In these respects as well as in general form 

 this species is much nearer to Ilingoceros than to Antilocapra. 



The toe bones were described and figured by Taylor 3 and as pointed 

 out by him, they are nearer to the form of the toe bones of Ilingoceros 

 than to any other forms at hand. They have a distinct "roman-nose" 

 dorsal contour, which is characteristic of antelopes as contrasted with 

 deer. The dorsal convexity, as pointed out by Taylor, is not as marked 

 as in Antilocapra. 



3 Op. cit. 

 Transmitted May, 



1914. 



