94 



R. S. Lull — New Tertiary Artio dactyls. 



until, toward the middle of the skull, the ridges swing 

 backward to unite and form the parietal crest, while 

 with a graceful curve the suture swings across the skull. 

 Thus there is denned a triangular area, bounded in front 

 by the curved suture and on either side by the supra- 

 temporal ridges. The sagittal crest is low and very thin, 



Fig. 4. Skull of Aletomeryx. A, male, dorsal aspect; B, frontal region 

 of female, showing horn, h, and triple frontal foramen, ff; C, male, ventral 

 aspect, cf, condyloid fossa; fo, foramen ovale; pal, palatine; pc, pterygoid 

 crest; pf, palatine foramen; z, zygomatic arch. Other letters as in fig. 2. 

 One-third natural size. 



Fig. 5. Hyoid. A, Aletomeryx, to be compared with B, Antilocapra. 

 m, muscular angle. One-third natural size. 



almost a knife-like ridge. In Antilocapra it does not ex- 

 ist, while in Dromomeryx it is low and broad. The 

 temporal ridges are not very well defined, but are roughly 

 parallel with the supratemporal ; they fade out entirely 

 on the superior aspect of the skull. A foramen occurs 

 in the left parietal near the sagittal crest in the female 

 skull No. 10735. One can not verify its presence in any 



