THE CHIMPANZEES AND ORANGS. 1 1 1 



The fourth cervical vertebra. The notch between the diapophysis and zygapophysis 

 is wider than in the Esquimaux and deeper than in the Australian. The spine is 

 longer, and, as in the preceding vertebrae, is unsymmetrically bifurcate. 



The seventh cervical vertebra. This shows a marked superiority of size over that 

 of the Esquimaux, and still more so over that of the Australian. The diapophyses are 

 thicker and more produced : both, but especially the right, are perforated by smaller 

 foramina than those of the preceding cervical vertebrae. Besides the increase of size, 

 this vertebra differs from the preceding in the minor depth of the anterior articular 

 surface of the centrum, in the increase of that part transversely, and the absence of 

 any prominent plate from the costal part of the transverse process which now forms 

 simply the lower boundary of the arterial foramen ; in the greater length, breadth and 

 thickness of the diapophysial part of the same process ; and in the greater length and 

 thickness of the spine, which terminates in ar obtuse enlargement notched behind but 

 not bifurcate. The posterior zygapophyses are also relatively larger. 



The first dorsal vertebra. The diapophyses are longer, and less inclined upwards 

 than in the Esquimaux or Australian, and the aspect of the costal surface upon them 

 is more directly downwards. In the Australian it looks more outwards than in the 

 Esquimaux. The ridge along the lower part of the same process, here strongly deve- 

 loped, is feebly marked in the Esquimaux and is not present in the Australian. The 

 produced parts of the border of the anterior articular surface of the centrum formed by 

 the neurapophyses are more restricted to the upper and outer parts than in the pre- 

 ceding vertebrae. 



The second to the tenth dorsal vertebrae inclusive. In each of these the aspect of 

 the costal surface of the diapophysis is more directly downwards than in either the 

 Esquimaux or Australian^ 



The eleventh dorsal vertebra. This vertebra is characterized, as in the Esquimaux 

 and Australian, by the development of well-marked metapophyses from the upper and 

 fore part of the diapophyses, which are shorter and less thick than in the foregoing 

 vertebrae. The surface for the head of the rib has passed upon the side of the neural 

 arch. This differs from the preceding vertebra in the distinct development of the 

 metapophyses, in the diminished size of the diapophyses, which now cease to show the 

 well-defined articular surface, and in the diminished length with increased thickness of 

 the spine. 



The twelfth dorsal vertebra. This differs from that of the Esquimaux in the articular 

 surface for the rib being still confined to the side of the base of the neurapophysis and not 

 transferred to the diapophysis, which is short and obtusely pointed. The neural spine 

 has a less antero-posterior extent, and a more expanded summit. This vertebra differs 

 from the eleventh dorsal in the superaddition of small but distinct anapophyses, in the 

 increase of the metapophyses and diminution of the diapophyses. The posterior zyg- 

 apophyses are smaller, and have convex, instead of flat or slightly concave, surfaces ; and 



