370 



CHORD AT A. 



The vertebral column consists of a great number ol 

 vertebrae which are known as cervical^ or neck-vertebrae, 

 thoracic^ lumbar^ sacral and caudal Of these the cervical 

 are numerous, forming a very flexible neck; the thoracic 



Fig. 262. — Lateral View of Cervical Vertebra of 

 THE Pigeon. {Ad nat.) 



Posterior Zygapophysis. 



Anterior Zygapophysis. 





%-' 



Heterocoelous Articulation. 



I 



-J) 



Cervical Rib. 



Vertebrarterial Canal. 



are largely fused together and rigid, while a great number 

 of the caudal are also fused. 



The fourteen cervicals have (except the first two) cervical 

 ribs fused on to them, and as the ribs have two heads their 

 fusion with the vertebra forms a canal on each side, called 



Fig. 263. —A Rib of the Pigeon. {Ad nat.) 

 (Slightly magnified). 



Tuberculum. 



Capitulum. 



Vertebral Part. 



Sternal Part. 



the vertebrarterial canal because it transmits the vertebral 

 artery. The vertebrae are called heterocoelous to describe 

 their peculiar articulations with each other, which are convex 

 in one direction and concave the other, like a saddle. The 



