4H3 THE RABBIT chap. 



axis, has ils cenlrum produced anteriorly into a conical odontoid process, 

 which fits into the lower part of the ring of the atlas and ib held in its 

 place by a ligament extending transversely across the latter : it is ossi- 

 fied from a distinct centre, and probably represents the true centrum 

 of the atlas. The neural spine of the axis is elongated and compressed, 

 and its transverse processes small and perforated each by a vertebrarterial 

 canal. Zygapophyses are present only on the posterior face of the 

 arch. In all the other cervical vertebrae, the transverse processes are 

 also perforated by the vertebrarterial canal, and except in the seventh 

 or last, are divided into dorsal and ventral lamelLe. The zygapophyses 

 lesemblc those of the thoracic vertebra described above. The seventh 

 cervical vertebra has a longer spine than the others, and bears a pair 

 of half facets rm the posterior surface of its centrum with which the first 

 jiair of ribs in part articulate. 



A typical ihoiaiic vertebra has already been described. In the tenth, 

 the neural spine is vertical, and in the remaining two or three, which arc 

 larger than the others, it slopes forwards. In the posterior three or 

 four there arc no tubercular facets, the ribs in this region not being 

 forked ; and the capitular facets are entire, and arc situated on the 

 corresponding centrum only. Additional processes arc present above 

 the pre-zygapophyses from the ninth thoracic vertebra onwards. 



The huubar vertebrni' are relatively large, increasing in size from 

 before backwards, and their various ])roces.ses are greatly devel- 

 oped. The neural spines are directed upwards and forwards, the 

 transverse processes are large and project oulward.s, downwards, and for- 

 wards. As in the posterior thoracic vertebra.-, there are stout processes 

 aliovc Ihe pre-zygapophyses, and there is also a pair of more .slender 

 processes below the post-zygapophy.ses and a median ventral process 

 projecting downwards from the cenlrum in the first two. 



Theirrrrt?/ \crtebr.u.irefuscd together In form the sacnun,\\\\\z\\ supports 

 the pelvic arch. The firsthand to a less extent the second also — has 

 large, expanded, transverse processes which articulate with the ilia: 

 these are the sacral vertebnc proper, the others, which decrease in size 

 from before backwards, are really the anterior caudal vertebn'C which 

 fuse with the true sacral vertebr.e io form a compound sacrum. 



The more anterior caudal vertebr.v resemble those of the sacral 

 region, but on )iassing backwards all the processes are seen to diminish 

 in size, until nothing but the centra are left at the end of the 

 tail. 



