156 



PEOPESSOE OWEN ON THE fiBNUS DINOENIS. 



{p,ps) is longitudinally channelled and ridged ; the riblet is shortened, as in Struthio ^ 

 but in a greater degree. The interzygapophysial bar, though short, leaves a foramen 

 before it is lost in the base of the postzygapophysis. The metapophysis (fig. 14, m, m) 

 is a mere slight outswelling of the diapophysial mass. The anterior depression at 

 the haemal surface of the centrum is no longer defined ; it is the beginning: of the 



O ' DO 



longitudinal channel A, banked by the hypapophyses. Behind these the surface is 

 smooth and flat ; then again becomes slightly concave transversely at the expanded 

 hind part of the centrum, pc. 



The neural spine is represented by a pointed ligamentous surface above the fore 

 border of the arch ; behind this rises the pair of low obtuse processes subsiding into 

 the hyperapophyses above the postzygapophyscs. 



As the neural roof subsides behind the part between the bases of the parial, quasi- 

 neural, spines, their connecting-bar is so indicated. The hind part of each spine extends, 

 subsiding to the hyperapophyses. 



TWELFTH VERTEBEA (i natural size). 

 Fig. 1.5. Fig. 10. 



Aspects. 

 Fig. 15, lateral ; 1<5, postaxial. 



The twelfth cervical is chiefly distinguished by the nearer proximity to one another 

 of the hypapophyses, the extremities of which, in a direct hind view (fig. 16, hy), 

 appear below the divisions of the postaxial surface, pc, not at its sides, as in Struthio ''. 

 The transverse diameter of the postaxial part of the neural arch, taken outside the 

 pedicles, is one fourth less than the same diameter of the preaxial part. The riblet 

 (fig. 15, 2)1), though longer than in the six or seven preceding cervicals, is relatively 



' ilivart, he. cit. fig. 2.5, p. 400. " lb. he. cit. p. 493, fig. 30, c. 



