114 B. S. Lull — New Tertiary A rtio dactyls. 



possesses a ridge. The mid-shaft in Aletomeryx is actu- 

 ally wider than in Antilocapra. Another sternal, which 

 may be the f ourth, is broad and flat, with dilated extremi- 

 ties and a concave dorsal surface. Ventrally, there is 

 a slight longitudinal ridge which is lacking in the prong- 

 buck. 



Relative dimensions are: 



Aletomeryx Antilocaigra 



m. m. Eatio 



Manubrium. 



Length 0360* -0550 1-53 



Width, posterior end -0117 -0170 1-53 



Depth, posterior end -0100 -0170 1-70 



Least width -0085 -0080 0-94 



Sternal IV. 



Length -0280 -0410 1-46 



Greatest width 0260 -0334 1-28 



Least width 0140 -0547 3.92 



Ay. 1-77 

 Incomplete. 



APPENDICULAR SKELETON. 



Fore Limbs. 



Scapula (fig. 14). — Many scapular fragments are pres- 

 ent, one pair being in excellent condition. Of these, one, 

 the smaller left, which is on the mounted specimen, is 

 proximally perfect and distally partly restored from the 

 impression in the matrix. The other, right, is left out of 

 the mount, as it would be embedded in the flesh, and is 

 therefore available for description. It resembles that of 

 Antilocapra, as the figures show (see fig. 14), differing 

 mainly in being more widely triangular in proportion to 

 the length. The ratio of the last dimension greatly ex- 

 ceeds that of vertebral dimensions, as is apparent from 

 the measurements. The spine is high, with a slightly re- 

 flected edge in its upper portion. In Antilocapra, the 

 reflected edge extends to the acromion. Muscular im- 

 pressions are comparable. The posterior margins are 

 slightly different. The same is true of the position of the 

 nutritive foramina. The round ligament is clearly im- 

 pressed in the glenoid fossa in Antilocapra. In Aleto- 

 meryx there is only a slight marginal notch. The outline 

 of the fossa is somewhat more regular in the fossil. 



The measurements are : 



