348 
MR.  R.  OWEN  ON  THE  OSTEOLOGY  OF 
by  the  lateral  boundaries  of  the  orbits  and  the  zygomatic  archest  The  orbits  are 
situated  higher  in  the  Chimpanzee  than  in  the  Orang,  and  are  larger  in  proportion  to 
the  entire  skull,  but  their  plane  is  more  perpendicular,  and  they  are  wider  apart.  In 
neither  the  Chimpanzee  nor  the  Orang  are  the  orbits  so  deep  in  proportion  as  in  the 
human  subject.  The  supraorbital  nerves  and  vessels  leave  a  slight  depression,  and  do 
not  pass  through  a  foramen.  The  lachrymal  bones  are  entirely  confined  to  the  orbit,  as 
in  the  higher  Quadrumana. 
A  character  by  which  the  Chimpanzee  approximates  more  closely  than  the  Orang  to 
the  human  subject  is  presented  by  the  nasal  bone,  which  projects  in  a  slightly  arched 
form  beyond  the  inter-orbital  plane,  while  a  trace  of  its  original  separation  into  two  la- 
teral elements  remains  at  the  lower  margin  of  the  now  consolidated  and  single  bone :  its 
upper  expanded  extremity  was  anchylosed  with  the  frontal  bone  in  the  adult  specimen 
here  described. 
The  malar  bones  are  largely  developed,  as  in  Man  and  the  Quadrumana  generally. 
Two  or  three  small  foramina  are  observable  on  the  exterior  of  the  orbital  process  ;  corre- 
sponding/oramma,  but  of  much  larger  size,  are  constantly  met  with  in  the  Orang.  The 
infraorbital  canal  is  continued  unclosed  to  within  2  lines  of  the  rim  of  the  orbit :  it  opens 
upon  the  face  by  a  single  foramen.  In  one  young  Chimpanzee  I  have  observed  a  second 
small  foramen.  In  the  Orang  there  are  usually  three  or  more  infraorbital  foramina,  as 
in  many  of  the  inferior  8imi(s. 
The  ascending  or  nasal  portion  of  the  superior  maxillary  bone,  which  is  of  greater  pro- 
portionate size  than  in  the  human  subject,  does  not  mount  vertically  to  the  orbits,  as  in 
Man  and  some  of  the  lower  Quadrumana,  (those,  for  instance,  of  the  genera  Cebus  and 
Callithrix) ,  but  slopes  backwards  as  in  the  Cynocephali  and  in  the  Carnivorous  Mammalia, 
but  in  a  less  degree.  The  contour  of  the  upper  jaw,  from  the  nasal  aperture  to  the  in- 
cisor teeth,  is  almost  straight,  while  in  the  Orang  it  is  rendered  concave  by  the  greater 
development  of  the  intermaxillary  bones  in  the  anterior  direction.  These  bones  are  an- 
chylosed to  the  maxillary  bones  in  the  adults  of  both  the  Chimpanzee  and  Orang.  In 
Simia  Satyrus  the  obliteration  of  the  suture  is  incomplete  until  the  full  development  of  the 
huge  laniarii,  but  in  the  Chimpanzee  the  anchylosis  takes  place  at  a  much  earlier  period ; 
although  in  the  young  animal,  when  the  first  dentition  is  completed,  traces  of  the  original 
separation  of  the  intermaxillary  bones  from  the  maxillaries  are  still  visible  at  the  sides  of 
the  nasal  aperture  and  on  the  palate  external  to  the  foramina  incisiva.  The  situation  of 
these  foramina  is  always  indicative  of  the  original  extent  of  the  palatal  process  of  the  in- 
termaxillary or  incisive  bones,  and  in  no  Quadrumana  are  they  so  close  to  the  incisive 
teeth  as  in  Man.  One  of  the  admeasurements  in  the  subjoined  Table  shows  the  relative 
extent  of  the  bony  palate  anterior  to  the  foramina  incisiva  in  the  young  and  adult 
Orang  and  Chimpanzee,  and  proves  that  the  latter  species  makes  a  nearer  approach  to 
Man  in  this  particular.    In  the  human  subject,  in  the  foetus  of  which  the  existence  of 
'  Compare  figg.  1  &  2,  Plate  LVI. 
