Peterson: The Osteology of Promerycochcerus. 



109 



The Fifth Cervical (Fig. 8). — The fifth cervical has a longer neural 

 spine, more delicate transverse processes, and a larger foramen for 

 the vertebral artery than the two preceding vertebrae. In all other 

 characters it is very similar to these. 



The Sixth Cervical (Fig. 9). — The inferior lamella of the transverse 

 process of this vertebra extends somewhat lower down, but apparently 

 has not the relative antero-posterior diameter, which obtains in 

 Merycoidodon cidbertsoni. The superior branch of the transverse 

 process, however, is more robust and extends outwards and backwards. 

 The median keel on the inferior face of the centrum is less strongly 

 developed than on the anterior vertebra.', the centrum is more de- 

 pressed, and the arterial canal larger than in any of the other vertebra; 

 in the cervical series. The neural spine is robust and of considerable 

 hcieht. 



9 10 



Fig. 9. Lateral view of the sixth cerv-ical vertebra of Promerycochcerus carrikeri. 



No. 1047; \ nat. size. 

 Fig. 10. Lateral view of the seventh cervical vertebra of Promerycochcerus carrikeri. 



No. 1047; \ nat. size. 



The Seventh Cervical (Fig. 10). — This vertebra is characterized by 

 its high and heavy neural spine, its depressed and strong pedicles, and 

 the presence of a small arterial canal, which pierces the transverse 

 process a<: the base near the inferior border. The centrum is much 

 depressed, and is broad on the under face, especially behind, opposite 

 the facet for the head of the rib. The posterior intervertebral notch 

 is deep, and a deep groove continues downward upon it between the 

 trans\-erse process and the sharp border of the capitular facet for the 



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