118        MR.  R.  OWEN  ON  THE  ANATOMY  OF  THE  CONCAVE  HORNBILL. 
The  oesophagus,  when  inflated,  is  1  inch  in  diameter,  and  is  continued,  as  in  the 
Toucan,  of  nearly  the  same  width  to  the  gizzard.  Two  inches  of  its  termination  are 
occupied  by  the  zone  of  gastric  glands,  composed  of  two  closely  aggregated  oval  groups 
which  are  continuous  with  each  other.  The  glands  are  simple  cylindrical  follicles,  about 
a  line  and  a  half  in  length. 
The  gizzard  is  thicker  in  its  coats,  and  of  a  more  elongated  form  than  in  the  Toucan. 
It  measured,  when  distended  with  fluid  after  death,  2^  inches  in  length,  and  U  in  its 
greatest  diameter.  Its  cuticular  lining  is  very  tough,  and  disposed  in  longitudinal 
ridges.  The  muscular  coat  is  3  lines  in  thickness  at  the  middle  of  the  gizzard,  but 
this  thickness  does  not  prevail  over  more  than  a  third  part  of  the  cavity  ;  the  rest  of 
this  tunic  is  less  than  a  line  in  thickness. 
The  duodenal  fold  extends  7  inches  from  the  pylorus.  The  remainder  of  the  intes- 
tinal canal  is  disposed  in  two  similar  folds,  and  then  extends  along  the  middle  line  of 
the  back  part  of  the  abdomen  to  the  cloaca.  There  are  no  cceca.  The  coats  of  the 
intestinal  canal  are  stronger  than  is  usual  in  Birds,  and  the  diameter  more  consider- 
able. The  ileum  at  its  commencement  measures  2  inches  2  lines  in  circumference :  it 
gradually  narrows  to  the  commencement  of  the  straight  portion,  or  rectum,  which  again 
becomes  wider  to  its  termination. 
The  whole  length  of  the  intestinal  canal  is  5  feet. 
The  villi  are  very  long  and  numerous,  but  diminish  in  both  respects  as  they  approach 
the  rectum,  where  they  degenerate  into  small  obtuse  papilla.  A  great  part  of  the  hning 
membrane  appeared  to  have  been  in  a  state  of  subacute  inflammation. 
The  liver  is  composed,  as  usual,  of  two  lobes,  the  right  being  the  larger.  The  duct 
of  the  right  lobe  emerges  from  the  right  side  of  the  transverse  portal  fissure,  and  be- 
comes attached  to  the  fundus  of  the  gall-bladder  ;  after  running  upon  it  for  half  an  inch 
it  receives  the  cystic  duct  by  an  oblique  aperture  directed  downwards  or  distad.  The 
common  or  cyst-hepatic  duct  then  passes  onwards,  and  terminates  in  the  duodenum  at 
the  extremity  of  its  fold,  14  inches  from  the  pylorus.  The  duct  of  the  left  lobe  of  the 
liver  terminates  separately  in  the  duodenum  about  half  an  inch  from  the  preceding.  The 
gall-bladder  is  If  inch  long,  and  1  inch  in  diameter. 
The  pancreas  commences  from  the  low^er  end  of  the  spleen  by  a  small  oval  enlarge- 
ment, which  soon  contracts  to  the  size  of  a  crow-quill.  This  attenuated  portion  of  the 
gland  passes  down  within  the  duodenal  fold,  gradually  enlarging,  and  terminates  in  a 
flattened  oblong  mass,  forming  the  head  of  "the  pancreas :  from  this  part  a  second  elon- 
gated lobe  is  continued  upwards,  ascending  along  the  opposite  side  of  the  fold  of  the 
duodenum  to  within  an  inch  of  the  pylorus.  The  pancreas  is  thus  seen  to  correspond 
with  the  form  of  the  duodenum,  being,  as  it  were,  similarly  folded  upon  itself;  but  not 
occupying  the  whole  fold  of  the  duodenum.  Its  secretion  is  conveyed  into  the  intestine 
by  three  ducts,  one  from  the  head  of  the  pancreas,  which  enters  the  duodenum  at  the 
bend  of  the  fold ;  and  a  second  and  third  from  the  elongated  lobes,  which  ducts  terminate 
