i84 ZOOTOMY. 



from before backwards, flattened from above downwards a^ 

 its anterior end, almost square in section posteriorly : its 

 anterior and posterior faces by which it articulates with the 

 preceding and succeeding vertebra respectively are cylin- 

 droidal, the anterior face being concave from side to side and 

 convex from above downwards, the posterior face convex 

 from side to side and concave from above downwards. 



7. The neurapophyses, upwardly directed processes, 

 rising one on each side from the dorsal surface of the cen- 

 trum, and meeting with one another in the middle line above, 

 forming the neural arch, thus helping to close in the 

 neural canal in which the spinal cord is contained. Each 

 neurapophysis is slightly excavated in front, considerably 

 excavated behind, so that in the articulated vertebral column 

 a series of intervertebral foramina are left between 

 successive neurapophyses and serve for the exit of the 

 spinal nerves. 



8. The neural spine, a median vertical plate arising 

 from the dorsal surface of the neural arch. 



9. The anterior zygapophysis, a stout forwardly 

 directed process, arising from the front edge of each neura- 

 pophysis and bearing a flat articular facet which looks 

 upwards and inwards, and is overlapped by the posterior 

 zygapophysis of the vertebra next in front. 



10. The posterior zygapophysis, a similar, back- 

 wardly directed process arising from the hinder edge of each 

 neurapophysis : it bears an articular facet which looks 

 downwards and outwards, and overlaps the anterior zygapo- 

 physis of the vertebra next behind. 



11. The transverse process, a stout, outwardly 

 directed rod springing from the outer face of each neurapo- 

 physis : it bears on its under surface a small tubercular 

 facet for the tubercle of the rib (§ 14). 



