10 FOSSIL REPTILIA O* THE 



Figs. 14, 15 and 16 show a smaller cervical vertebra, of a more depressed form, not 

 due to crushing. The centrum is much depressed; the pneumatic foramen (fig. 15, 

 o ) partakes of the same modification of form, and is a longer ellipse than in the 

 vertebra (fig. 7) ; the neural canal retains its normal cylindrical shape, with slightly 

 expanded outlets. The form of the posterior zygapophysis is perfectly preserved on 

 one side, in fig. 11, z, and the articular surfaces on both sides in fig. 16, z ; they are 

 relatively larger than in fig. 11. In fig. 15 more of the base of the neural spine 

 remains than in most other specimens. 



Figs. 17 and 18 are of a rather shorter and probably more advanced cervical 

 vertebra, but of very similar proportions ; in it the neural arch (fig. 1 7) is more entire 

 than in most specimens, the anterior (a) as well as posterior {z) zygapophyses being 

 preserved ; the more frequent loss of the anterior pair is due to their being more 

 slender and more produced. The under surface of the centrum (fig. 18) shows no 

 rising of the middle part, the hypapophysis having a less extended base than in the 

 vertebra, (fig. 12.) The inner surface of the anterior zygapophysis (fig. 18, a), is 

 divided by a notch from the border of the articular concavity of the centrum. 



Fig. 19 gives a view of a section of a mutilated cervical vertebra, nearly equal in 

 size with fig. 7, and similar in form. The shape of the neural canal, the large cancelli, 

 and the thin superficial compact crust of the bone, are well shown in this section. 



At the base of the neck, or beginning of the back, the vertebrae suddenly decrease 

 in length ; the hypapophysis disappears, or is represented only by a slight production 

 of the lower border of the anterior cup ; the parapophyses are less produced, the 

 lower surface of the centrum is flattened, and presents the quadrate form shown in 

 figure 20. There is now a considerable development from the fore part of each side 

 of the neural arch and contiguous part of the centrum, and thereby the last cervical 

 or first dorsal vertebra of the Pterodactyle more resembles the corresponding 

 vertebra of the bird. The parapophysis, diapophysis, and rudimental rib coalesce 

 around the vertebraterial foramen ; an oblique ridge is continued from the upper 

 border of the anterior articular cup upon the parapophysis ; a parallel oblique ridge is 

 continued from the anterior zygapophysis downward and outward upon the pleur- 

 apophysis ; the diapophysis makes a low obtuse projection above the pleurapophysis and 

 behind the zygapophysis. Above these developments the neural arch contracts 

 from before backward, to an extent of 5 lines, as compared with a total vertebral 

 breadth, anteriorly, of 1 inch 8 lines ; it then rapidly expands, rising vertically at its 

 fore part, and developing at its back part the posterior zygapophyses, the articular 

 facets of which look more directly outward than in the long cervical vertebrae ; the 

 superincumbent tubercle (fig. 22, c) is more distinct from the facet (ib., z) ; the 

 posterior zygapophyses are also much more approximated than in those vertebrae ; 

 they are separated behind by a semicircular concavity ; the base of the neural spine 

 in the vertebra here described measured 6 lines in length by 3 in breadth. The 



