364 
MR.  R.  OWEN  ON  THE  OSTEOLOGY  OF 
from  that  of  Man  in  the  inclination  of  its  spine  towards  the  superior  costa ;  in  the 
acromion  being  narrower  and  claviform,  not  an  extended  flattened  process  ;  and  in  the 
absence  of  the  flattened  and  overhanging  margin  of  the  spine  which  we  find  in  the  hu- 
man subject.  The  supra-spinal /o5sa  is  also  larger  and  deeper  in  the  Orang,  the  superior 
costa  and  spine  of  the  scapula  lying  in  nearly  parallel  lines  ;  while  the  subspinal  fossa 
is  shorter  from  above  downwards,  and  does  not  present  any  convexities,  as  in  the  hu- 
man subject.  The  coracoid  process  has  a  greater  inchnation  downwards,  and  the 
glenoid  cavity  is  directed  more  upwards  than  in  Man,  but  its  form  is  the  same.  In  the 
Orang,  therefore,  the  scapula,  as  compared  with  that  of  the  Chimpanzee,  is  shorter  in 
proportion  to  its  breadth,  its  spine  is  less  perpendicular  to  its  plane,  and  the  upward 
curvature  of  the  acromion  is  greater^ 
The  principal  feature  of  the  organization  of  the  Orang,  and  that  in  which  it  differs 
most  from  the  Chimpanzee,  is  the  relative  length  of  the  upper  and  lower  extremities. 
The  arms  reach  to  the  heel.  The  articular  surface  of  the  head  of  the  humerus  is  larger 
in  Simia  Satyrus  than  in  Man,  its  extent  equalling  a  complete  hemisphere.  The  twist 
of  the  shaft  is  not  so  remarkable,  nor  the  groove  at  the  posterior  and  outer  part  for  the 
musculo-spiral  nerve  and  artery.  In  some  specimens  the  humerus  is  perforated  between 
the  condyles. 
In  the  radius  and  ulna  the  principal  differences  are  seen  in  the  greater  space  existing 
between  them,  owing  to  the  outward  curve  of  the  radius,  and  in  the  absence  of  the 
acute  margin  on  its  ulnar  aspect :  the  corresponding  spine  in  the  ulna  is  also  less 
marked  than  in  the  human  subject.    Dr.  Jeffries  observed  "  a  large  curved  projection 
'  With  respect  to  the  scapula  Dr.  Harwood  (Linnean Transactions,  vol.  xv.  p.  472.)  obseiTes,  that  "  The  sca- 
pulcB  of  the  Pongo  have  their  spine  strongly  incurvated  upvpards,  while  in  the  Simia  Satyrus  it  pursues  almost  a 
straight  direction  horizontally :  the  space  also  for  the  attachment  of  the  infra  spinatus  muscle  is,  relatively  to  the 
size  of  the  bone,  far  more  extended  in  the  Pongo."  On  comparing  the  scapula  of  the  young  Orang  with  those  of 
the  Pongo,  I  confess  myself  unable  to  appreciate  the  differences  here  pointed  out ;  but  judging  from  the  peculiar 
inclination  of  the  spine  and  the  acromion  towards  the  superior  costa,  both  in  the  young  and  the  adult  Orang, 
I  should  infer  from  this  particular  rather  a  specific  identity  than  a  difference.  I  therefore  subjoin  the  follow- 
ing admeasurements,  accurately  taken  from  the  same  relative  positions  of  the  scapula  of  two  specimens  of  Si- 
mia Satyrus  of  different  ages,  and  of  the  adult  Orang  or  Pongo. 
Younger  im-    Older  imma-    Pongo,  or 
mature  Orang.  ture  Orang.    adult  Orang. 
in.  lines.       in.  lines.       in.  lines. 
From  the  extremity  of  the  acromion  to  the  root  of  the  coracoid  process       10  15  2  4 
From  the  root  of  the  acromion  to  the  root  of  the  coracoid  process  .    .         7  11  14 
From  the  root  of  the  acromion  to  the  inferior  angle  of  the  scapula  ..23  .33  510 
From  the  root  of  the  spine  to  the  inferior  angle  of  the  scapula  ...  2  2     8  4  5 
From  the  root  of  the  spine  to  the  superior  angle  of  the  scapula      .    .         4  10  14 
These  admeasurements  show  that  the  progress  of  the  spine  from  the  base  of  the  scapula  to  the  root  of  the 
acromion,  which  is  indicated  by  the  second  and  fifth  admeasurements  of  the  younger  immature  Orang,  has  un- 
dergone a  greater  proportional  change  in  the  older  immature  specimen  than  in  the  adult  Orang.  The  third  and 
fourth  admeasurements  show  that  the  increased  size  of  the  subspinal  fossa  is  regularly  progressive  in  each. 
