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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- 
gular 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  vertebra  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  vertebrcB,  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 vertebra  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  vertebra 
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  vertebra  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  vertebra  joined  together ;  but  this  appear- 
ance may  result  from  partial  ossification  of  the  sciatic  ligaments  :  and  this  is  the  more 
