332 SCOTT. [Vol. XI. 



of the seventh cervical, but smaller, more concave and without 

 the internal accessory facet. The neural arch is narrower and 

 more strongly convex and the spine is thicker, though of less 

 antero-posterior extent, and inclined backward instead of being 

 erect ; the postzygapophyses are on the inferior face of the 

 overhanging neural arch. The pedicels of the arch are very 

 narrow at their point of origin, being deeply notched behind 

 for the passage of the spinal nerves. The transverse processes 

 are long, heavy and prominent and end in large concave facets 

 for the tubercles of the first pair of ribs. Compared with the 

 corresponding vertebra of MoscJius, the chief differences to be 

 observed consist in the greater breadth of the neural arch and 

 the longer transverse process in the fossil. 



The first and second thoracic vertebrae are somewhat different 

 from the others, since they form a transition from the structure 

 of the cervicals. The second has a rather more trihedral and 

 less depressed centrum than the first, a somewhat heavier and 

 longer spine and shorter transverse processes. The prezyga- 

 pophyses are on the anterior face of the neural arch, but are 

 widely separated. From the second to the sixth thoracic the 

 centra gradually become shorter, less depressed, and more dis- 

 tinctly trihedral in section; the transverse processes shorten 

 and terminate in smaller flat or slightly convex facets for the 

 rib tubercles, instead of concave surfaces; the spines increase 

 in length and the zygapophyses draw near to the median line. 

 The sixth appears to have the longest spine of the series, 

 though this point cannot be determined with certainty. Back 

 of this the spines gradually decrease in height, but still incline 

 strongly backward until the (supposed) eleventh thoracic is 

 reached, which is the anticlinal vertebra. The transverse 

 processes continue long and prominent and still have relatively 

 large rib-facets, but on the eleventh (?) they are greatly reduced 

 and disappear on the twelfth Q). The latter has postzyga- 

 pophyses of the cylindrical pattern and corresponding anterior 

 processes appear on the thirteenth Q.). The centra of the 

 posterior thoracic vertebrae have become considerably elongate ; 

 they have subcircular faces, but are constricted and of trihedral 

 section in the middle. 



