[    65  ] 
VII.  On  the  sacculated  Form  of  Stomach  as  it  exists  in  the  Genus  Semnopithecus,  F.  Cuv. 
By  Richard  Owen,  Esq.,  F.Z.S.,  Assistant  Conservator  of  the  Museum  of  the  Royal 
College  of  Surgeons  in  London. 
Communicated  June  11,  1833. 
In  the  dissections  of  the  animals  of  the  class  Mammalia  which  take  place  at  the  Mu- 
seum of  the  Society,  it  rarely  happens  that  the  more  important  organs  are  found  to 
present  any  remarkable  deviations  from  the  structures  already  known  and  described  as 
characterizing  the  genus  or  group  to  which  the  species  under  examination  may  belong. 
Nor  is  it  to  be  expected  that  novelties  of  much  importance  can  often  be  detected  in  a 
class  which  has  been  so  extensively  investigated.  Nevertheless,  the  necessity  of  con- 
tinuing these  examinations  at  every  opportunity  that  occurs,  must  be  admitted  by  every 
one :  anatomical  facts  become  more  valuable  to  the  physiologist  as  their  authenticity  is 
confirmed  by  repeated  examination ; — the  means  of  forming  conclusions  as  to  the  reci- 
procity of  function,  and  the  relative  value  of  different  organs,  from  their  varying  pre- 
ponderance in  different  animals  whose  habits  as  burrowers,  swimmers,  climbers,  &c., 
may  affect  the  different  functions ; — these  interesting  and  important  deductions  can 
only  be  founded  on  extensive  tabular  arrangements  of  the  weights  and  admeasurements 
of  the  different  organs.  But  whilst  the  anatomist  is  silently  accumulating  these  data, 
it  does  happen  every  now  and  then  that  unexpected  modifications  of  important  organs 
present  themselves,  the  discovery  of  which,  while  it  serves  as  a  healthy  stimulus  to  his 
exertions,  at  the  same  time  teaches  him  how  dangerous  it  is  to  draw  hasty  conclusions 
as  to  analogy  of  internal  structure  from  similarity  of  external  form. 
The  singularly  shaped  stomachs  which  are  now  before  the  Society  were  taken  from 
two  species  of  a  genus  of  Monkey,  the  Semnopithecus,  F.  Cuv.,  which  in  the  system  of 
Cuvier  ranks  only  fifth  in  the  descensive  gradation  from  Man.  This  genus  is  of  late 
formation,  and  not  entirely  the  result  of  newly  discovered  materials  :  several  species,  on 
the  contrary,  were  for  a  long  time  ranked  with  the  Guenons,  Cercopithecus,  in  which 
the  stomach  is  of  the  usual  simple  construction  :  and  it  is  almost  superfluous  to  remark 
in  this  place,  how  slight  is  the  essential  zoological  character,  viz.  an  additional  tubercle 
on  the  last  molar  of  the  lower  jaw,  which  distinguishes  genera  presenting  such  wide 
discrepancies  in  the  most  important  of  their  vital  organs. 
The  larger  of  the  two  stomachs  was  taken  from  a  full-grown  female  Entellus  Monkey, 
Semnopithecus  Entellus,  F.  Cuv.,  which  measured,  from  the  end  of  the  nose  to  the  root 
of  the  tail,  1  foot  8  inches.  The  admeasurements  of  the  stomach,  distended  and  dried, 
are  as  follows  ; — 
VOL.  I.  K 
