442 BRITISH FOSSIL REPTILES. 



same pit of the Upper Green-sand deposit near Cambridge. The condyloid liall 

 (fig. 12, c) neatly fits the cup c of fig. 14, and most probably belonged to the 

 same individual. All the characters described and figured in my paper on the 

 ' Vertebraa of Pterosauria,'* and in a preceding monograph, f are repeated in the 

 present larger specimens of the first and second neck-vertebrae. In the more 

 transverse extension of the posterior articular ball of the axis (fig. 16, b) the present 

 specimen agrees with the smaller of the two previously figured specimens of this 

 part of the vertebral column. | 



Cervical Vertebrce (PI. \i, figs. 1, 2, and 4). 



The middle (fourth or fifth?) cervical vertebra of a Pterodactyle, corresponding 

 in bulk with that indicated by the fossils above described and figured (PI. 11, figs. 

 1 — 16 ; PI. 12, figs. 1 — 3), agrees in the proportions of length and breadth more with 

 the smaller vertebrae (PI. 8, figs. 14—17) than with the vertebrae (ib., figs. 7 — 11) 

 described in pages 386 — 388. It shows the same posterior extension of the centrum 

 (fig. 2, *, p) beyond the neural arch {n), but with somewhat greater divarication of the 

 hinder processes {p) than in figs. 18 or 11 of PI. 8. The present specimen very 

 strikingly illustrates the characteristic breadth and depression of the centrum of the 

 middle cervicals of the large Green-sand Pterodactyles. The neural canal (fig. 2, «) 

 appears to be proportionally more contracted than in the smaller cervical vertebrae ; 

 it is relatively much smaller than in any bird, marking well the reptilian nature of 

 the extinct flying air-breather. The anterior surface of the diapophysial produc- 

 tions of the fore part of the base of the neural arch is marked by a groove extending 

 from above and within outwards and downwards. The whole base of the arch has 

 coalesced with the centrum ; the major part, with the neural spine and zygapo- 

 physes, has been broken away. 



An oblique side view of the last cervical vertebra of a similar-sized Ptero- 

 dactyle is given in PI. 12, fig. 4, showing the more produced diapophysis (rf), 

 perforated by vertebrarterial foramen (/), indicative of the development in this 

 vertebral segment of a rudimental rib, and of its coalescence with the other 

 elements, the whole extending below the level of the under part of the centrum. 

 Above and behind this foramen is that for tlie admission of air into the bone; it 

 is of a similar size, and of a narrow, elliptical form. The posterior zygapophysis 

 {z) is now raised to a higher level than the anterior one, indicating the sudden 

 bend of the neck at this part. The posterior processes {P) are smaller and less 



* 'Philosophical Transactions,' 1859, p. 1G5, pi. 10, figs. 28—34. 



f ' Palaeoiitographical Society,' vol. for 1857, pp. 7, 8. 



X Compare Tab. I, fig. l(i, with Tab. 11, fig. 1-1, and Tab. IV, fig. 2, of the ' Monograph ' of 1857. 



