THE CHIMPANZEES AND ORANGS. 11] 
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 vertebra, 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 vertebre. 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 vertebree. 
The second to the tenth dorsal vertebre 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 
vertebree. 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 cf 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 
