AESlNOITHElilUM. 
25 
large and massively constructed ; anteriorly it is bounded by the sharp border 
just mentioned ; posteriorly, on the other hand, it has a broad flat surface, and it 
is perforated near its base by the vertebrarterial canal [f.tr.). Its outer ends 
form broad, roughened, rather convex surfaces. 
Text-fig. 8, 
Ax4 
ns. 
Atlas vertebra of Arsinoitherium zitteli : A, from back ; B, from front ; C, from above. 
nx'., lateral surface for axis ; cond., surfaces for occipital condyles ; f.tr., vertebrarterial canal ; n.s., neural 
spine ; od., surface for odontoid process ; sp.f., foramen for first spinal nerve ; t.p., transverse process. 
4 nat. size. 
This atlas differs from that of the Dinocerata in being much wider, and in 
having longer transverse processes and a less convex neural arch. From the 
atlas of Elephas it differs in its much longer transverse processes, less convex 
arch, less developed spinous tuberosities, and smaller vertebrarterial canal. In 
E 
