358 SKELETON OF THE FOWL 



ii. The centrum is slender. The terminal arti 

 cular surfaces are saddle- shaped, the anterior 

 one being convex from above dovm wards, 

 and concave from side to side ; while the 

 posterior surface, which is larger and more 

 prominent, is concave from above downwards, 

 and convex from side to side. These saddle- 

 shaped articular surfaces are very character- 

 istic of the cervical vertebra of birds. 



iii. The neural arch is shorter than the centrum, 

 and deeply notched in the middle line, both in 

 front and behind. The neural arch is also 

 notched behind, on both sides, for the passage 

 of the spinal nerves, 

 iv. The neurapophysis is rudimentary in the 



middle cervical vertebrae. 

 V. The transverse processes and cervical ribs. At 

 the anterior end of the vertebra an irregular 

 process projects outwards at each side, which 

 is perforated at its base by a large foramen, 

 and is produced at its hinder border into a 

 ' sharp, backwardly directed process. 



This process is really a rib, which, as in 

 , the cervical vertebra of the rabbit, is fused 



with the vertebra; the foramen at its base, 

 which transmits the vertebral artery, corre- 

 sponding to the notch between the capitulum 

 and tuberculum of the rib. 



vi. The zygapophyses. 



The anterior zygapophyses are borne on 

 the upper surface of the transverse processes : 

 their articular surfaces are flat, and look up- 

 wards and inwards. 



The posterior zygapophyses project back- 

 wards from the posterior border of the neural 

 arch, their articular surfaces looking down- 

 wards and outwards. 



