94 PROFESSOR OWEN ON THE OSTEOLOGY OF 



series, which series is straight when extended. It differs also in the more uniform 

 transverse diameter of the bodies of the dorsal and lumbar vertebrae, the latter not 

 expanding in the same degree, as they approach the sacrum, as they do in the Human 

 subject. These general differences in the relative position and proportions of the ' true ' 

 vertebrse are repeated, and are rather more strongly marked in the Chimpanzee andOrang. 

 The comparison is instituted, throughout, with the Australian variety of the Human 

 species — a variety, of which the entire skeleton, and the separate bones, have not 

 hitherto been described and figured. 



The cervical vertebrae of the Gorilla are the same in number as in the class Mam- 

 maha generally, viz. 7. The number of dorsal vertebrae, or those bearing moveable 

 ribs, is 13; that of the lumbar vertebrae 4; that of the sacral vertebrae 5: the total 

 number of true or moveable trunk -vertebrae being the same as in Man, only the ribs 

 which answerto the transverse processes of the first lumbar in Man retain their distinct- 

 ness with a greater length, whilst those which form the transverse processes of the last 

 lumbar vertebra become modified, by age, like the same elements of the sacral vertebrae. 



Cervical Vertebrae (PI. XXXIII.). — Of the true vertebrae the cervical series departs most 

 from the Human type in the extraordinary length of the spines of the last five vertebrae 

 (PI. XXXIII. fig. 1 , 3, 4, 5, 6, 7) ; that of the fourth cervical ( 4 ) being not less than 3^ inches ; 

 those of the third and fifth are nearly of the same length, but are thicker, and have a shght 

 curvature in opposite directions, diverging in a slight degree away from the fourth ; 

 the spines of the sixth and seventh cervicals gradually decrease in length and increase 

 in thickness : the spine of the dentata ( 2 ) is trihedral, the surfaces being divided by 

 produced sharp ridges. The canal for the vertebral artery decreases in diameter from 

 the sixth {ib. fig. 6, v) forward to the atlas. 



The atlas (PI. XXXIII. fig. 2) has a less transverse and a greater fore-and-aft diameter 

 than that of Man (ib. fig. 8), with a wider neural canal (n), especially between the 

 condyles (z), which are smaller than in Man. An obtuse process is developed back- 

 wards from the part (hy) representing the body, which is broader than in Man ; the 

 perforation of the transverse process (v, fig. 3) is smaller, and that process is narrower, 

 especially vertically, and is slightly recurved : the groove behind the upper articular 

 processes is deeper and narrower. The neural spine is represented by a tubercle, which 

 is more developed in the older male skeleton of the Gorilla in the Paris Museum. 



The axis or dentata (fig. 4 & fig. I, 2) differs chiefly in the greater size of the neural 

 canal, and in the greater length and less breadth of the neural spine. This, however, 

 dilates at its extremity into a three-sided cone, with the broadest side downwards. 

 The zygapophyses are smaller, the transverse processes' are more directly perforated by 

 the arterial foramina, and the diapophyses are more produced, and more remote from 

 the posterior zygapophyses. The body is more quadrate behind. 



' This term is applied to the whole of the compound part marked d,p, and pi, in fig. 1, 3; d being the 

 diapophysis, p the parapophysis, and pi the pleurapophysis. 



