44 



THE PKJEVALSKY HOKSE. 



posterior foramina amounts to 13 mm. In comparison with the 

 dimensions of the wings, the length of the superior part, of the arch 

 is rather small. The fossae beneath the wings are very deep. The 



Fig. 12. — Atlas (dorsal aspect). 



tuberosity of the upper part of the arch (tuberculum posterior) is 

 only feebly developed. Measurements according to Nehring's 

 scheme ^ive the following figures : — 



Length of the Tipper part of the arch... 



Width of the wings on a level with the anterior foramina... 



Width of the wings on a level with the posterior foramina 



Width of the articular surface for the occipital condyles ... 



Width of the articular surface for the axis ... 



Width of the anterior end of the neural foramen ... 



Height of the anterior end of the neural foramen ... 



mm. 



39 



129 



142 



76 

 85 

 34 



27 



THE SECOND CERVICAL VERTEBRA (EPISTROPHEUS, 

 AXIS VERTEBRA. Fig. 13) is characterised by a fairly strong 





Fig. 13. — Axis (lateral aspect). 



development of the odontoid process. The two roots of the trans- 

 verse process, which in F. cahalhis are fairly widely separated 

 from each other, are nearer together in E . prjevalskii ; with the 



