V-] 



E DENT A TA. 



zygapophysis (pz} below, develops an articular surface 

 (pz 1 } which looks upwards and articulates with a corre- 

 sponding downward directed process (az l ) developed on the 

 upper part of the arch of the following vertebra, rather 

 below the metapophysis (;;/). Thus the vertebra has a 

 process projecting backwards, with flattened articular facets 

 on its upper and under surface, fitting into a deep recess 

 on the anterior edge of the arch of the vertebra behind, 



F'iG. 23. Posterior surface of second 

 lumbar vertebra of Great Anteater, . 

 t transverse process ; pz posterior 

 zygapophysis ; pz 1 , pz 2 , and pz$, ad- 

 ditional posterior articular facets. 



FIG. 24. Anterior surface of third lum- 

 bar vertebra of Great Anteater, . 

 t transverse process ; m metapo- 

 physis ; az anterior zygapophysis ; 

 az l , az 2 , and az$, additional anterior 

 articular facets. 



and the articulation is now by two zygapophysial surfaces 

 on each side of the arch instead of one. 



In the thirteenth x thoracic vertebra a third articular facet 

 (pz^) is developed on the hinder margin of the lamina of 

 the arch, still higher than the last additional one (pz l ), 

 and separated from it by a deep notch. This looks mainly 

 outwards, and articulates with a corresponding facet (as -, 

 Fig 24) on the anterior edge of the arch of the fourteenth 



1 In the Cambridge specimen this description applies to the fourteenth 

 and fifteenth vertebra respectively. 



