330 SCOTT. [Vol. XI. 



exact shape cannot be determined. Enough remains, however, 

 to show that its origin on the centrum is less extended in the 

 fore and aft direction than in Mosclms and in consequence the 

 posterior orifice of the vertebrarterial canal occupies a more 

 advanced position than in that genus. 



The sixth cervical has a centrum of nearly the same length as 

 the fifth and is of a similar depressed cylindrical shape. The 

 anterior face is strongly convex and hemispherical in shape, 

 with a large shallow pit, or sulcus, for the attachment of the 

 intervertebral cartilage ; the posterior face is as strongly con- 

 cave, but both faces are much less oblique with reference to 

 the long axis of the centrum than on the fifth vertebra. The 

 ventral keel is very feebly developed and does not terminate 

 behind in a tubercle, but simply dies away. The neural arch 

 is very short antero-posteriorly ; this is due to the manner in 

 which the arch is cut away between the prezygapophyses. 

 The axis of the neck undergoes a marked change in direction 

 between the fifth and sixth vertebrae and this is provided for 

 by the projection of the anterior zygapophyses on the latter. 

 These are broader, slightly more elevated and less oblique than 

 on the fifth, while the postzygapophyses are very much the 

 same on both, except that on No. 6 the articular surface is 

 continued down upon the neural arch, forming an accessory 

 facet ; the pedicels of the neural arch are higher and hence the 

 neural canal is more rounded and less depressed. The spine 

 does not appear to be much higher, but is decidedly thicker 

 and heavier and inclines forward to about the same degree. 

 As is always the case on the sixth vertebra, the transverse 

 process is very clearly divided into diapophysial and pleura- 

 pophysial elements. The former is a stout, depresse'd rod, 

 which stands out nearly at right angles with the centrum and 

 having the distal end expanded in the fore and aft direction ; 

 this process is decidedly more prominent than in Moschus. 

 The pleurapophysis is a very large plate, slightly convex on 

 the inner side and concave on the outer, with thickened free 

 border, especially at the angles. This element is developed 

 very much as in the musk-deer, but is of greater vertical height 

 and the inferior face of the centrum is more clearly demarcated 

 from the origin of the plates. 



