96 PROFESSOR OWEN ON THE OSTEOLOGY OF 
are absolutely as well as relatively less. There is no trace of spine in the adult male in 
the Museum of the Royal College of Surgeons ; but a tubercular rudiment is developed 
in the atlas of the older male skeleton in the Paris Museum. 
In the dentata of the Orang, the short transverse process resembles that of the 
Gorilla in being perforated, and it is not bifurcate: the neural spine is pointed in the 
College skeleton, but is slightly expanded at the end in the Paris skeleton. The 
posterior articular surface of the centrum is convex transversely, slightly concave 
vertically. The odontoid (true centrum of the atlas) is longer, in proportion to its 
thickness, than in Man; the anterior articular surfaces are narrower, the lower surface 
of the centrum is flatter, the spine is longer and more pointed, and the perforation in 
the transverse process relatively smaller thanin Man. The transverse convexity of the 
posterior surface of the centrum is greater, and the vertical concavity less than in Man. 
The third cervical vertebra, in the Orang as in the Gorilla, is chiefly distinguished 
from the corresponding Human vertebra by the length and slenderness of its simple 
spinous process. The transverse process has a short oblique pleurapophysial plate. 
In the fourth cervical vertebra the angles of the oblique lamelliform transverse process 
begin to be produced. In the fifth cervical the diapophysial and pleurapophysial 
portions project distinctly from each transverse process. In the sixth the pleurapo- 
physis, or rudimental rib completing the perforated transverse process, has not coalesced 
with the parapophysis ; and it has either not been ossified, or is lost in the adult 
skeleton examined. In the seventh cervical vertebra the transverse process is repre- 
sented, as in the Gorilla, by the diapophysis only, which is not perforated. 
The spinous processes of the last five cervical vertebra markedly differ, like those of 
the Gorilla, by their great length, from the corresponding parts in Man; but they are 
proportionally less developed than in the Gorilla. 
In the atlas of the Chimpanzee (Troglodytes niger), there is a short process from the 
back part of the hypapophysis (hy): the vertebral artery, after traversing the transverse 
process, also perforates the neural arch, but this may be an individual variety: the 
costal part of the left transverse process has not been ossified: that process is repre- 
sented by a short parapophysis and a long diapophysis, the vertebral foramen being, 
nevertheless, complete. A small ridge represents the neural spine. In comparison 
with the Orang, the breadth of the atlas exceeds its antero-posterior diameter chiefly by 
the length of the diapophysial part of the transverse process : it thus, as in the Gorilla, 
more nearly resembles that of Man in its general shape. It likewise resembles it more 
in the minor breadth and greater length of the part representing the body, in the larger 
and more definite surface on the upper part for the articulation with the .odontoid pro- 
cess, and in the greater breadth and more produced margins of the hinder articular 
processes. In all these approximations it agrees with the atlas of the Gorilla. 
In the dentata of the Chimpanzee the transverse processes are short and terminate 
simply and obtusely: the neural spine is trifid, having an anterior ridge and two ter- 
