404 SKELETON OF THE FOWL. 



i. The vertebra is very long and light, as compared 

 with the cervical vertebra of a rabbit. 



ii. The centrum is slender. The terminal arti- 

 cular surfaces are saddle-shaped, the anterior 

 one being convex from above downwards, 

 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 vertebrae of birds. 



iii. The neural arch is shorter than the centrum, 

 and is 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 neural spine 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 vertebrae of the rabbit, is fused 

 with the vertebra ; the foramen at its base 

 transmits the vertebral artery and corre- 

 sponds to the notch between the capitulum 

 and tuberculum of the rib. 



vi. The zygapophyses. 



The pre-zygapophyses are borne on the 

 upper surfaces of the transverse processes : 

 their articular surfaces are flat and face up' 

 wards and inwards. 



The post-zygapophyses project backwards 

 from the posterior border of the neural arch, 



