254 TEETIAEY VEETEBEATA OE THE FATtTM. 



are separated ventrally by an interval of about 2 cm. The neural arch is a comparatively 

 narrow bar of bone connected antero-externally v^ith the upper border of the condylar 

 prominences by a thin bar of bone as described above ; on the front of the bar there is 

 a lov?" median ridge [n.sp.), but on the hinder face there is a flat facet, against which 

 the antero-ventral surface of the arch of the axis fits (see text-fig. 83, D). The 

 transverse process {t.p.) is short and massive and directed a little backwards; on the 

 posterior face, immediately outside the edge of the surface for the axis, there is a small 

 foramen, which, however, does not seem to perforate the transverse process, but merely 

 leads into the bone. The surfaces for the axis are wide above, narrowing ventrally, 

 and passing into the surface for the odontoid without interruption ; they are slightly 

 convex from side to side. The ventral bar bearing the odontoid facet is stout and 

 is produced downwards into a sharp-hooked hypapophysis {hyp.) ; from Lucas's 

 description* it seems that a similar process is present in the atlas oi Zeuglodon cetoides. 

 In the axis (text-fig. 83, B, D) the odontoid process {od.) is short, blunt, and 

 rounded, passing at least ventrally into the lateral surfaces [at.) for the atlas. These 

 are quadrate in outline, and nearly flat or even very slightly concave from side to side. 

 The neural arch is high, and the neural spine {n.sp.) high and massive ; it is triangular 

 in section, the posterior surface being flat, while the two anterior faces meet in an 

 acute angle, the lower end of which overhangs the odontoid process ; or the ventral 

 face of this projecting portion of the arch is a flat facet which articulates with the corre- 

 sponding surface on the posterior side of the neural arch of the atlas (text-fig. 83, D). 

 The posterior zygapophyses {p.z.) are well developed. The transverse process {t.p.) is 

 a flange of bone directed a little backwards, and extending from the base of the neural 

 arch to the ventral border of the centrum ; externally it is divided into an upper and 

 lower process, and its base is perforated obliquely by a vertebrarterial canal {v.c). 

 The posterior face of the centrum is much broader than high ; it is slightly concave, 

 and in this specimen the epiphysis is not completely fused with the rest of the centrum. 

 The ventral face of the centrum is imperfect. The third cervical (text-fig. 83, C, D) 

 is remarkable for the extreme shortness of the centrum, which in the middle is only 

 about 1'5 cm. through, while its width is at least 5 cm. The centrum is oval in 

 outline, and is completed by anterior and posterior epiphyses {ep.), here still separated ; 

 the anterior and posterior faces are slightly concave. The neural arch is high, and 

 rises into a short stout neural spine {n.sp.) directed a little backwards. Both the 

 anterior {a.z.) and posterior zygapophyses {p.z.) are well developed and nearly circular 

 in outline. The transverse process {t.p.) is wide, and consists of a narrower upper bar 

 arising from the base of the arch and a much broader ventral bar from the lower half 

 of the centrum; these unite externally, enclosing a large vertebrarterial canal {v.c), 

 and forming a broad plate, the outer angle of which is produced a little downwards. 



* Amer. Naturalist, vol. xxix. (1895) p. 746. 



