SKELETON OF THE CROCODILE. VERTEBRAL COLUMN. 239 



the upper jaw. In Crocodiles the first tooth bites into a pit, 

 the fourth into a notch in the upper jaw. 



II. ENDOSKELETOK 

 1. THE AXIAL SKELETON. 



This includes the vertebral column, the skull, and the ribs 

 and sternum. 



A. THE VERTEBRAL COLUMN. 



The vertebral column is very long, consisting of some sixty 

 vertebrae. It can be divided into the usual five regions, the 

 cervical, thoracic, lumbar, sacral, and caudal regions. 



10 



FIG. 41. 



FlKST FOUR CEKVICAL VERTEBKAE OF A CROCODILE (C '. 



(Partly after VON ZITTEL.) 



pro-atlas. 7. tubercular portion of fourth 



lateral portion of atlas, 

 odontoid process. 8. 



ventral portion of atlas. 9. 



neural spine of axis. 10. 



postzygapophysis of fourth 

 vertebra. 



cervical rib. 

 first cervical rib. 

 second cervical rib. 

 convex posterior surface of 



centrum of fourth vertebra. 



THE CERVICAL VERTEBRAE. 



Counting as cervical all those vertebrae which are anterior 

 to the first one whose ribs meet the sternum, there are nine 

 cervical vertebrae, all of which bear ribs. 



As a type of the cervical vertebrae the fifth may be taken. 



