AESINOITHEEIUM. 



29 



slightly concave. The transverse processes are large knobs v^ith rib-facets {t.f.) on 

 their antero-lateral surfaces. The anterior zygapophyses {a.z.) are placed very low, 

 little above the level of the top of the centrum. The neural arch rises into a high 

 backwardly directed neural spine {n.sp.), the anterior face of which is formed by two 



Ax4 



Text-fig. 11. 



B X ^: 



Anterior thoracic vertebra o£ ArsinoitJierium zitteli : A, from front; B, from right side. 

 a.z., anterior zygapophysis ; c.f., capitular facet ; n.sp., neural spine ; p,s., posterior zygapophysis ; 



t.f., tubercular facet. | nat. size. 



Text-fig. 12. 



Middle thoracic vertebra of Arsinoitherium zitteli : A, from front ; B, from right side. 

 Lettering as in text-fig. 11. j nat. size. 



surfaces meeting at a sharp angle, while the posterior face is concave ; towards 

 the summit the spine tends to become bifid. The anterior capitular facets [c.f.) are 

 placed low down on the sides of the centrum, the posterior ones higher up. 



Further back in the series (text-fig. 12) the body of the centrum becomes 



