414 



ME. ST. GEOEGE MIVAET ON THE 



Excavations occur preaxially, as in the preceding vertebra ; but postaxially they may 

 exist close to the postaxial margin of the diapophysis, extending inwards to the base of 

 the neural spine. 



The neural spine is more extended dorsally and slightly so antero-posteriorly ; its 

 dorsal margin is rather convex, and bifurcates slightly at each end. That concavity 

 which in the preceding vertebra exists on each side of the preaxial root of the neural 

 spine is here deeper. 



The postaxial fossa is smaller ; and the margins of the lamina? which laterally bound 

 it form rather less than a right angle with the postaxial margin of the neural spine. 



The zygapophysial articular surfaces are again slightly diminished. The twenty-first 

 vertebra supports a long rib, which articulates by its distal end with the second 

 sternal rib. 



The Twenty-second Vertebra. 



This vertebra is of about the same size as the twenty-first, in some respects less deve- 

 loped, in others more so. 



Its centrum has its premial surface entirely occupied by the articular surface, and the 

 ventral margins of both coincide, as there is no hypapophysial production. The surface 

 is deeper dorso-ventrally, is less laterally produced, and may have its dorsal and ventral 

 margins more concave and convex respectively. 



Fig. 49. 



TWENTY-SECOND VERTEBRA (| natural size). 

 Eisr. 50. 



Pig. 51. 



Fig. 49, lateral aspect ; 50, doreal aspect ; 51, preaxial aspect. Letters as before, except v, excavation on 



preaxial side of diapophysis. 



Excavations are to be seen on the preaxial, postaxial, and ventral aspects of the diapophysis, the preaxial 



one being very much the larger. 



The postasdal surface of the centrum is rather larger and flatter, but very similar in 

 figure to that of the twentieth vertebra ; its dorsal margin, however, is rather wide and 

 less concave. 



The neural surface of the centrum is more concave transversely at its preaxial part 

 than in the vertebra last described. 



