362 
MR.  R.  OWEN  ON  THE  OSTEOLOGY  OF 
of  the  Orang  wants  the  knob  at  the  back  part  of  the  ring  which  is  observable  in  Man ; 
it  presents  here  merely  a  roughness  of  the  surface.  The  spine  of  the  dentata  has  a 
ridge  along  its  upper  part,  and  its  extremity  is  slightly  bifurcate ;  the  spines  of  the 
other  cervical  vertehrcB  are  simple  ;  that  of  the  fifth  is  the  longest ;  those  of  the  sixth 
and  seventh  have  a  slight  inclination  towards  the  head,  indicating  that  the  centre  of 
motion  in  this  region  of  the  vertebral  column  is  nearer  the  head  than  in  Man.  The 
transverse  processes  of  the  fifth  and  sixth,  especially  the  latter,  are  longer,  and  inclined 
more  forwards  and  downwards  than  in  the  Chimpanzee  or  in  Man.  The  whole  of  the 
cervical  region  is  proportionally  shorter  than  in  Man,  and  consequently  better  adapted 
to  support  the  head. 
The  entire  vertebral  column  has  one  general  curve  dorsad  from  the  atlas  to  the  com- 
mencement of  the  sacrum,  where  there  is  a  slight  curve  in  the  contrary  direction. 
The  number  of  the  dorsal  or  costal  vertebra  in  the  Orang  is  twelve,  as  in  the  human 
subject.  This  is  one  of  the  more  important  differences  between  the  Orang  and  Chim- 
panzee :  the  number  in  the  latter  animal,  as  previously  noticed,  being  thirteen. 
The  number  of  the  lumbar  vertebree  is  four,  as  in  the  Chimpanzee.  This,  at  least,  is 
the  case  in  the  skeleton  of  the  Pongo  preserved  in  the  Museum  of  Comparative  Ana- 
tomy in  the  Garden  of  Plants  at  Paris,  and  in  the  trunk  of  the  skeleton  of  the  adult 
Orang  in  the  collection  of  the  Zoological  Society ;  in  which  latter  specimen,  as  the 
bones  are  connected  by  their  natural  ligaments,  there  is  no  room  for  supposing  a  ver- 
tebra to  have  been  accidentally  lost.  This  fact  it  is  the  more  necessary  to  state,  be- 
cause the  skeleton  of  the  Pongo  in  the  Museum  of  the  College  of  Surgeons  in  London 
differs  from  those  above  mentioned  in  having  an  additional  lumbar  vertebra ;  and  as  the 
skeletons  of  the  young  Orangs  have  uniformly  presented  but  four  lumbar  vertebros, 
some  stress  has  been  laid  on  the  additional  vertebra  of  the  above  specimen  of  Pongo, 
as  indicative  of  its  specific  difference  from  the  young  Orang^.  The  additional  lumbar 
vertebra  in  the  College  specimen  indicates,  however,  its  abnormal  character  by  its  form 
and  situation :  it  is  lodged  deeper  in  the  interspace  of  the  ossa  innominata  than  the  last 
lumbar  vertebra  of  the  adult  Orang  in  the  Museum  of  the  Zoological  Society ;  and  the 
right  transverse  process  is  expanded  like  that  of  a  sacral  vertebra,  and  is  joined  to  the 
ilium  in  a  corresponding  manner.  The  human  subject  occasionally  presents  a  similar 
lusus  of  an  additional  lumbar  vertebra ;  and  in  the  skeleton  of  an  Australian  native, 
where  the  number  of  lumbar  vertebra  is  normal,  I  have  also  observed  that  the  last  has 
the  left  transverse  process  similarly  expanded  and  joined  to  the  ilium,  as  has  been  de- 
scribed in  the  Orang.  The  lumbar  vertebra  have  much  shorter  spines  in  the  Orang  than 
in  the  Chimpanzee. 
The  sacrum  deviates  from  that  of  Man  in  the  same  particulars  as  in  the  Chimpanzee, 
but  is  longer,  narrower,  and  straighter.    In  counting  the  vertebra  of  this  part,  I  have 
been  guided,  as  in  human  anatomy,  by  the  circumstance  of  their  being  perforated  for 
'  See  Dr.  Harwood's  paper,  Linnean  Transactions,  vol.  xv.  p.  473. 
