98 PROFESSOR OWEN ON THE OSTEOLOGY OF 



proportion to its breadtli than in the Gorilla, Chimpanzee, or Orang. The surface for the 

 odontoid process, or true body of the atlas, is more nearly circular and better defined. The 

 vertebral artery, after perforating the transverse process, grooves the neural arch behind 

 the produced angles of the upper zygapophysis (fig. 8, z). The cavity for the occipital 

 condyle is relatively larger, deeper, with the margins more produced. The parapophysial 

 boundary {p) of the vertebral arterial foramen (v) is thicker than the diapophysial 

 one (d) ; they are equal in the Gorilla : the arterial foramina are relatively larger and 

 the lower zygapophyses (fig. 9, s') are relatively much larger than in the Gorilla. 



These differences chiefly relate to the more secure articulation and support of the 

 vertically-sustained head, and to the larger size of the cerebral organ, in part nourished 

 by the vertebral arteries, in the Human species. The development of the zygapophyses 

 gives a greater antero-posterior extent to those parts of the atlas, and the transverse 

 processes are thicker in proportion to their length. 



In the Australian the anterior surface of the body of the dentata (fig. 10) is less 

 flattened than in the Gorilla (fig. 4) or Chimpanzee, the middle line being produced 

 almost into a ridge ; its hindei' border is more rounded. The transverse process {pi) is 

 thicker and more obtuse in proportion to its length : both the anterior and posterior 

 zygapophyses are relatively larger : the neural canal is relatively wider transversely : 

 the neural spine is much less developed : in fact, what is usually described as the bifur- 

 cated spine of the axis seems rather to be the upper slightly-produced extremities of the 

 not completely coalesced neurapophyses of that vertebra in Man. Lines drawn parallel 

 with the transverse plane of the anterior zygapophyses would meet at a right angle in 

 the Chimpanzee, but at a more open angle in Man, especially in the White races. 



In the third cervical vertebra (fig. 7,3), the upper angle of the base of each neur- 

 apophysis is produced forwards beyond the centrum, and assists in forming, but in a less 

 proportion than in the Gorilla or Chimpanzee, the transverse concavity for the produced 

 body of the axis. The centrum is larger in proportion to the rest of the vertebra than 

 in the Chimpanzee, save in its length. The pleurapophysial part (pi) of the transverse 

 process forms a distinct obtnse angle from the diapophysial part, which is shorter, thicker 

 and more obtuse than in the Chimpanzee. The same difference is here repeated in the 

 greater relative size of the zygapophyses, particularly the anterior ones. The transverse 

 diameter of the neural canal is relatively greater. The neural spine {n s) is very much 

 shorter than in the Gorilla : it is, however, simple, not bifurcate, as usually in Europeans. 



In the fourth cervical vertebra {ib. 4 ) the sides of the upper concavity of the body are 

 still formed by the neurapophyses, which are less produced than in the preceding ver- 

 tebrae, or than in the corresponding vertebras of the Gorilla. The diapophyses are 

 shorter than in the Chimpanzee ; the neural spine is considerably shorter than in the 

 Gorilla. The zygapophy.ses are relatively larger. The pleurapophysial and diapophysial 

 parts of the transverse process are nearly equally developed, and are bent upwards on 

 the sides of the groove which impresses the upper part of the transverse process. The 



