350 MR. R. OWEN ON THE OSTEOLOGY OF 
extended to increase the surface of attachment of the muscles of mastication ; the zygo- 
matic arches are proportionally strengthened and widened to admit the passage of the 
temporal muscles ; and these cover by their extensive origin a considerably greater pro- 
portion of the cranium in the adult than in the young Chimpanzee: but in all these par- 
ticulars the Chimpanzee recedes in a minor degree from the human construction than 
the Orang. 
With respect to the os hyoides, I cannot agree with Tyson in the observation, ‘ hu- 
mano ferme simillimum existit”: the body, on the contrary, is expanded into a trian- 
cular form, and hollowed out behind for the reception of one of the laryngeal sacculi ; 
the cornua minora are also proportionally more developed. 
The vertebral column of the Chimpanzee presents fewer deviations from that of the 
human subject than the cranium. The number of true vertebre is the same ; but an addi- 
tional pair of ribs takes one from the lumbar to be added to the dorsal or costal series. 
With respect to the cervical vertebre, Audebert, in his description of the skeleton of 
the Pongo of Wurmb, particularly remarks, that in the length of the spinous processes 
that animal differed not only from every other Ape, but from every other Mammal. 
In the Chimpanzee, however, there exists a similar provision for an adequate origin 
of the muscles that are inserted into the occiput, and are designed to counterbalance 
the preponderating weight anterior to the centre of support. The spines of the cer- 
vical vertebre are simple and elongated, not short and bifurcated as in the human 
subject: that of the third vertebra is the shortest, with the exception of the atlas, 
where, as is usually the case, the spine is wanting. The bodies of the lumbar vertebre 
are proportionally smaller in the Chimpanzee than in Man, where they are enlarged to 
afford a basis of support to the column above in reference to his erect position, and 
where this region of the spine is proportionally of greater length. The recedence of the 
Chimpanzee from the Bimanous type of structure is manifested still more strongly by the 
narrowness and length of the sacrum, its smaller curvature, and its parallelism with the 
spine. A peculiarity in the Chimpanzee is observable in the position of the last lumbar 
vertebra with relation to the iliac bones ; these rise on either side of, and are partially 
joined to, that vertebra, so that it might almost be reckoned as belonging to the sacral 
series. In the adult specimen here described, the transverse processes of this vertebra 
are expanded, thickened, and joined to the ilium: in one skeleton of a young Chimpan- 
zee I have observed the transverse processes of the fourth lumbar vertebra modified in 
the same manner. 
The false vertebre in the adult skeleton are seven in number, but the sixth is anchy- 
losed with the sacrum, both by its body and transverse process, so as to give rise by 
that union to an additional pair of antero-posterior sacral foramina ; the sixth vertebra 
is not, however, perforated like the five preceding ones for the spinal chord. The 
seventh seems to be composed of two vertebre joined together; but this appear- 
ance may result from partial ossification of the sciatic ligaments: and this is the more 

