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Annals of the Carnegie Museum. 



extends further below the odontoid process, and is divided from 

 the pedicle by a deep round notch, which is sometimes bridged over 

 by a bony process, as in the peccary. The inferior keel of the centrum 

 has a straighter axis. The posterior border of the neural spine is 

 slightly excavated, and displays a broad transverse rugose surface, 

 terminating in the overhanging process. The transverse process 

 is directed more outwardly and the entire bone is more robust 

 than in Merycoidodon, showing that it supported heavier muscles 

 and a thicker neck. The foramen for the vertebral artery is large 

 and pierces the base of the transverse process parallel with the long 

 axis of the centrum. 



6 78 



Fig. 6. Lateral view of the third cervical vertebra of Promerycochcerus carrikeri 



No. 1047; \ nat. size. 

 Fig. 7. Lateral view of the fourth cervical vertebra of Promerycochcerus carrikeri. 



No. 1047; "3 nat. size. 

 Fig. 8. Lateral view of the fifth cervical vertebra of Promerycochcerus carrikeri, 



No. 1047; \ nat. size. 



The Third Cervical Vertebra (Fig. 6). — The centrum of the third 

 cervical is slightly opisthocoelous, short, and depressed. Below there 

 is a strong median keel with deep excavations on either side. The 

 pedicle is low, the neural canal rather small, and the superior surface 

 of the arch rugose with heavy anterior and posterior zygapophyses. 

 The articulation of the postzygapophysis faces more obliquely out- 

 ward and upward than in Merycoidodon, and the transverse process 

 is proportionally longer and more robust, especially in the postero- 

 lateral direction. 



The Fourth Cervical (Fig. 7). — This vertebra corresponds in nearly 

 all respects with the one preceding it and need not here be described 

 in detail. 



