793 



as in Man, only the ribs which answer to the transverse processes of the first lumbar in Man 

 retain their distinctness with a greater length. 



Cervical Vertebra. Of the true vertebrae the cervical series departs most from the Human 

 type in the extraordinary length of the spines of the last five vertebrae ; that of the fourth 

 cervical being not less than three inches and a half ; those of the third and fifth are nearly 

 of the same length, but are thicker, and have a slight curvature in opposite directions, away 

 from the fourth, the third forwards and the fourth backwards, in a very slight degree ; the 

 spines of the sixth and seventh cervicals gradually decreaseXin length and increase in thick- 

 ness : the spine of the dentata is trihedral, the surfaces Wring divided by produced sharp 

 ridges : the canal for the vertebral artery decreases in diametes from the sixth forward to the 

 atlas. The bodies of these vertebrae are longer in proportion to their breadth than in Man, 

 and the lower (pleurapophysial) part of the transverse process of the sixth is more suddenly 

 increased in length and breadth, and diverges more from the upper division of the same pro- 

 cess. The atlas is narrower than in Man, with a wider neural canal, especially between the 

 condvles, which are smaller than in Man. An obtuse process is developed backwards from 

 the part representing the body, which is broader than in Man ; the perforation of the trans- 

 verse process is smaller, and that process is narrower, especially vertically ; the groove behind 

 the upper articular processes is deeper and narrower. The axis or dentata differs chiefly in 

 the greater size of the neural canal, and in the greater length and less breadth of the neural 

 spine ; the zygapophyses are smaller, the transverse processes are more directly perforated 

 by the arterial foramina, and the diapophyses are more produced, and more remote from the 

 posterior zygapophyses. 



The bodies of the succeeding cervical vertebrae are longer in proportion to their breadth ; 

 the basis of the neurapophysis ascends to embrace the hinder half of the antecedent vertebra 

 as in Man. The difference observable in the dentata is manifested in excess in the third cer- 

 vical vertebra, the spinous process of which more than doubles the vertical diameter of the 

 rest of the vertebra ; the neural canal also exceeds that of Man in the same diameter ; the 

 zygapophyses are smaller than in Man : the arterial canal is transversely elliptic, not cir- 

 cular ; the transverse process is longer, more slender and more simple ; the pleurapophysial 

 not projecting distinctly from the diapophysial part ; the diapophysis is more remote from 

 the zygapophysis ; the neurapophyses are much thicker and stronger ; the long neural spine 

 becomes subcompressed and slightly dilated at its extremity, which is not bifurcate. The 

 same general differences, and especially the very striking one in the length of the neural 

 spine, are manifested in the fourth cervical vertebra, but the pleurapophysial part of the 

 transverse process is now distinctly developed as a triangular depressed plate produced for- 

 wards and a little downwards ; the lower part of the centrum is proportionally less than in 

 Man, and the smaller size of the zygapophysis is the more remarkable in contrast with the 

 larger proportions of almost all the rest of the vertebrae. In the fifth cervical vertebra the 

 zygapophyses equal hi size those of the corresponding vertebra in Man ; the pleurapophysial 

 part of the transverse process is less developed than it is in the fourth : the arterial canal is 

 wider, the anterior and posterior zygapophyses are more nearly upon the same plane, and 

 the neural arch has a greater antero-posterior extent ; the superior thickness of the neurapo- 

 physis above these processes is very striking : the arterial canal of the transverse process 



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