169 



prominence, which carries on its anterior surface a facet 

 lor the above-mentioned facet on the posterior arch of 

 the atlas. The anterior border of the fused bodies is pro- 

 longed into a well-marked triangular, dorso-ventrally com- 

 pressed odontoid process, of which nearly the whole of the 

 inferior surface is marked with an articulating surface for the 

 a.tias. This anterior border carries, also, relatively large triangular 

 or pyriform articular facets for the atlas, which extend nearly up 

 to the base of the odontoid process. 



The transverse processes of the ankylosed vertebrae are repre- 

 sented by a minute but distinct conical projection (omitted in 

 fig. 5), wdiich corresponds, in position, with the fifth and sixth, or 

 fourth, fifth and sixth vertebr?e, but it apparently contains, also, 

 the fused representatives of all five. From this, a slender bony 

 bar passes to a point about the middle of the lateral edge of the 

 fused bodies, thus forming a sort of vertebrarterial canal. Pos- 

 teriorly the fused mass presents a broad shallow U-shaped articular 

 surface, which, m its central part, articulates with the body of 

 the next vertebra, and by the lateral parts with the first rib. 



The seventh vertebra (PL A^II., figs. 5, 6 and 8) has 

 a dorso-ventrally compressed body, which articulates with the 

 bodies of the vertebne in front and behind. Its neural arch is 

 slender and ring-like, without any spinous process. Tlie trans- 

 verse process is well marked, and bears anterior articulating 

 surfaces on the dorsal surface of its root, which face upwards. 

 The posterior zygapophyses have their articular surfaces looking 

 downwards. 



In the eighth vertebra (PI. YIL, figs. 6 and 8) the body is 

 similarly compressed dorso-ventrally. The spinous process is very 

 long, and both it and the laminae of the neural arch slope much 

 backwards, so that a wide gap is left between this and the neural 

 arch of the preceding vertebra, which inclines forwards. The 

 transverse process, not so prominent as in the seventh vertebra, 

 carries at its root an anterior articular surface which looks 

 upwards. On its under surface, looking forwards and a little 

 outwards, and extending inw^ards, so as to be continuous with the 

 posterior articular surface of the body, is a surface for articula- 

 tion with the first rib. Posterior zygapophyses, rudimentary, 

 with their articular surfaces lying almost entirely on the in- 

 ternal surfaces of the root of the laminte and, from the obliquity 

 of these, facing much downwards as well as inwards. At the 

 posterior part of the lateral border of the body, and continuous 

 with its posterior articular surface, is a facet which, with a cor- 

 responding facet on the body of the next vertebra, constitutes 

 the articulation for the head of the second rib. 



Reckoning the vertebra, just described, as the first of the 



