THE  CHIMPANZEE  AND  ORANG  UTAN. 
351 
probable,  as  in  the  skeletons  of  the  young  Chimpanzee  preserved  in  the  Hunterian 
Museum,  after  the  four  lumbar  vertebrts,  there  remain  only  seven  for  the  sacrum  and 
coccyx.  Of  these  vertebra  only  the  first  two  have  their  transverse  processes  fully  deve- 
loped ;  with  reference  to  which  it  is  interesting  to  remark,  that  in  the  adult  Chimpanzee 
only  the  two  superior  sacral  vertebra  are  united  to  the  iliac  bones  ;  and  hence  the  trunk 
is  less  firmly  connected  with  the  pelvic  arch,  and  consequently  is  more  in  need  of  ad- 
ditional support  from  the  anterior  extremities,  than  in  Man. 
The  pelvis  of  the  Chimpanzee  differs  from  that  of  Man  in  all  those  particulars  which 
characterize  the  Quadrumana,  and  which  relate  to  the  imperfection  of  their  means  of 
maintaining  the  erect  position.  The  iliac  bones  are  long,  straight,  and  expanded  out- 
wardly above,  but  narrow  in  proportion  to  their  length  ;  the  posterior  surface  is  concave 
for  the  lodgement  of  the  glutcei  muscles  ;  the  anterior  surface  nearly  flat,  and  stretching 
outwards  almost  parallel  with  the  plane  of  the  sacrum.  The  whole  pelvis  is  placed  more 
in  a  line  with  the  spine  than  in  Man :  its  superior  aperture  is  elongated  and  narrow,  so 
that  the  whole  of  the  sacrum  and  coccyx  is  visible  on  a  front  view.  The  tuberosities 
of  the  ischia  are  broad,  thick,  and  curved  outwards.  The  pubic  bones  are  broad  and 
deep,  but  flattened  from  before  backwards.  With  this  general  conformity  with  the 
Quadrumanous  type,  there  is,  however,  a  provision  for  a  more  extended  attachment  of 
the  glutcei  muscles,  in  a  greater  breadth  of  the  ilia  between  the  superior  spinous  pro- 
cesses, which  also  incline  forwards  more  than  is  observable  in  the  inferior  Simia  ;  and 
it  may  thence  be  inferred  that  the  semi-erect  position  is  more  easily  maintained  in  the 
Chimpanzee. 
An  important  difference  between  the  Chimpanzee  and  Orang  is  manifested  in  the 
relative  size  and  strength  of  the  lower  extremities,  in  which  respect  the  Chimpanzee 
claims  a  closer  relationship  to  Man.  Both  animals,  however,  exhibit  as  permanent 
conditions,  proportions  of  the  inferior  extremities  which  are  transitory  in  the  human 
subject :  in  the  Orang  they  have  the  curtailed  proportions  which  they  present  in  the 
human  foetus  of  six  months'  gestation  ;  in  the  Chimpanzee  they  retain  the  same  relative 
size  as  in  the  yearhng  infant.  It  is,  however,  a  remarkable  and  interesting  fact,  that 
the  lower  extremities  instead  of  being  shorter  in  proportion  to  the  trunk  in  the  young 
Chimpanzee  are  longer,  their  adult  relations  arising  from  the  increased  development  of 
the  trunk  and  anterior  extremities,  which  are  thus  made  fit  for  the  vigorous  acts  of 
climbing  ;  and  in  relation  to  which  a  corresponding  increase  of  the  inferior  extremities 
would  have  been  detrimental :  so  that  the  immature  Chimpanzee  tends  to  the  great  pro- 
totype of  animal  organization  in  two  ways,  viz,  a  disproportionate  magnitude  of  brain 
and  cranium,  and  an  imperfect  development  of  trunk  and  arms,  which  are  both,  how- 
ever, circumstances  peculiar  to  its  nonage. 
The  femur  of  the  Chimpanzee  is  shghtly  bent  in  the  anterior  direction,  as  in  the 
human  subject :  the  neck  of  the  bone  has  the  same  comparative  length,  but  stands  out 
more  obhquely  to  the  shaft.  The  whole  of  the  body  of  the  bone  is  flatter  or  more  com- 
3  A  2 
