494 MANUAL OF ZOOLOGY SECT. 



The thoracic vertebrae all have elongated spines. The 

 transverse processes are short and stout ; each bears near 

 its extremity a small, smooth articular surface or tubercular 

 facet for the tubercle of a rib. On the anterior and posterior 

 borders of each vertebra is a little semi-lunar facet, the 

 capitular facet, situated at the junction of the centrum and 

 the neural arch. The two contiguous semi-lunar facets of 

 successive vertebrae form between them a cup-like concavity 

 into which the head or capitulum of a rib is received. 



cent 



FIG. 298. Lepus cuniculus. A, atlas and axis, ventral aspect, od, odontoid pro- 

 cess of axis. B, lateral view of axis, art, articular facet for occipital condyle; 

 od, odontoid process; pt. zy, post-zygapophysis; sp, neural spine. C, thoracic 

 vertebrae, lateral view, cent, centrum; fac, facet for rib; met, metapophysis; 

 pr. zy, prezygapophysis; pt.zy, post-zygapophysis; rb, rib; sp, spinous process. 



In the lumbar region the spines are comparatively short, 

 and both transverse processes and bodies are devoid of 

 facets. 



The sacral vertebrae are firmly ankylosed together to 

 form a single composite bone, the sacrum. The first and 

 second bear great expanded lateral plates sacral ribs 

 with roughened external surfaces for articulation with the 

 ilia. 



Of the caudal vertebrae the more anterior resemble those 

 of the sacral region and have similar processes ; but as we 

 pass backwards in the caudal region all the processes gradu- 



