920 THE OSTEOLOGY AND MYOLOGY OF THE DEATH ADDER, 



internal face of the posterior portions of the diverging laminae. 

 The excavation is made from above downwards and outwards, but 

 the floor runs downwards, inwards and backwards. Into this niche 

 on either side a facet of the zygosphene fits, " like the joints called 

 tenon-and-mortice in carpentry " (Owen). 



Prezyga2oophysis : The prezygapophysis is supported on a 

 pedicle of bones that runs upwards from the diapophysis. The 

 articular fane looks upwards, is oval, with a process from its 

 anterior border. It runs downwards, inwards, and backwards. 

 It articulates with the posterior zygapophysis of the preceding 

 vertebra. The pedicle that supports the zygapophysis sends up 

 a well-marked process external to the articular facet. This we 

 consider to be a metapophysis. It gives attachment to the 

 levatores costarum, longissiraus, and intertransversarii muscles. 



Postzyga20O2:)hysis : The postzygapophysis is not so strongly 

 built as the anterior, the reason being that the anterior is the 

 supporting zygapophysis. 



The articular facet is situated on the inferior surface, and 

 consequently looks downwards, while at the same time it runs 

 inwards, forwards, and slightly upwards, a small projection pro- 

 ceeding backwards from its posterior edge. 



The superior surface of the zygapophysis is flattened, and is 

 continuous with the external surface of the lamina. To this is 

 attached the semispinalis. 



Transverse Process : The transverse process is represented by 

 a small projection of bone from the external side of the anterior 

 portion of the centrum. On this projection an articular face is 

 developed which is made up of two tubercles. The superior 

 tubercle projects outwards, is rounded, convex, and more posterior 

 than the inferior, which is oval, slightly convex, and larger than 

 the superior. Between the two tubercles there is a depression, 

 concave from above downward^. The axis of the whole articular 

 face is downwards and forwards. Leading from the inferior 



