108 



R. 8. Lull — New Tertiary Artio dactyls. 



parallel and the median notch on the antero-ventral mar- 

 gin is much less pronounced. The position and develop- 

 ment of both dorsal and ventral tubercles correspond, as 

 do the several foramina. There is of course slight indi- 

 vidual variation among the several atlases before me, 

 which I have designated Nos. 1-3. The measurements, 

 all maximum, follow: 



illB 



Fig. 9. Atlas, dorsal aspect. A, Antilocapra; B, Aletomeryx. One- 

 third natural size. 



Fig. 10. Axis, left lateral aspect. A, Antilocapra; B, Aletomeryx. One- 

 third natural size. 



Fig. 11. Cervical VI. A, Antilocapra; B, Aletomeryx. One-third nat- 

 ural size. 



Fig. 12. Dorsal I. A, Antilocapra; B, Aletomeryx. One-third natural 

 size. 



Fig. 13. Sacrum. A, dorsal aspect, Antilocapra; B, same, Aletomeryx; 

 C, left lateral aspect, Antilocapra; T>, same, Aletomeryx. One-third nat- 

 ural size. 



