532 CETACEA. 



The sixth vertebra is distinguislied from the foregoing by the very great develop- 

 ment of the inferior transverse process, which is directed forwards and outwards 

 with a shght upward curve. It is a rounded rod-like structure, separated by a 

 deep oval notch from the superior transverse process, the length of which it 

 equals. It arises from the lower half of the centrum, and the left is shorter than 

 the right. The pedicles of the neural arch are better develojDcd in this than in any 

 of the preceding vertebrae. The zygapophyses of the left side, unlike those of the 

 preceding vertebrae, are nearly on the same plane and are not separated by a notch, 

 and the conjoint, antero-posterior expansion of the two is considerably in excess of 

 that of the right zygapophyses, which are disunited externally by a small notch, 

 almost converted into a canal by the approximation of the posterior and anterior 

 extremities of the borders of the facets. The superior transverse process is also 

 rod-like with a smaller extremity and one directed outwards and forwards. The 

 neural canal partakes of the same asymmetry that distinguishes the preceding 

 vertebrae, but even in a more marked degree, the left having considerably greater 

 capacity than the right half. The arch is strong but backwardly twisted on the 

 left side. There is a faint ridge in place of a spinous process, and a small process 

 on the hinder border of the lamina. The centrum is thicker antero-posteriorly 

 than in the three preceding vertebrae, but its articular surfaces are similar to those 

 in the fourth and fifth. 



The seventh cervical is distinguished by its well-developed pedicles, falcate 

 spinous process, and well developed transverse processes. The body is thicker than 

 in the sixth vertebra, and its articular surfaces are transversely oblong. Its under 

 surface is marked by a longitudinal furrow perforated by a distinctly defined fora- 

 men. The nem'al canal is triangular, very shghtly broader than liigh. The neural 

 arch is twisted obliquely from side to side, the right being broader than the left half 

 and anterior to it. The spinous process is as high as the length of one of the laminse. 

 It is directed backwards with a slight twist to the left. The zygapophyses are quite 

 separate with the facets on the same plane. The transverse process arches outwards, 

 slightly backwards, and is faintly curved downwards, especially at its extremity, 

 above which it is marked by a roughened nodosity. At the base of the transverse 

 process anteriorly occurs the irregular rough surface to which the head of the first 

 rib is articulated. 



Dorsal vertebrce. — The first dorsal vertebra is distinguished by its sharp pointed 

 almost falcate-like spinous process, whereas in all the other dorsal vertebrae 

 this process is abruptly truncated at its extremity. The first four vertebrse differ 

 from the rest of the dorsal segments, by having their transverse processes borne by 

 the pedicles and by the absence of metapophyses. Then- transverse processes 

 decrease in size, and the vertebrae in lateral expansion, by the gradual shortenino of 

 the neural laminae, and the processes are brought down nearer and nearer to 

 the bodies. These latter, however, increase in transverse breadth and antero- 

 posterior thickness from before backwards. The laminae also become much reduced 

 in transverse expansion from the first to the fourth dorsal, and in the latter the 



