MR.  R.  OWEN  ON  THE  ANATOMY  OF  THE  BRACHIOPODA. 
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Fig.  1 1 .  A  magnified  view  of  the  superior  mantle-lobe  injected,  with  the  hearts, 
ovary,  digestive  and  nervous  systems. 
12.  A  highly  magnified  view  of  a  small  portion  of  the  brachial  tentacles  and  stem. 
13.  A  highly  magnified  view  of  a  small  portion  of  the  edge  of  the  mantle,  show- 
ing the  terminal  divisions  of  the  branchial  vessels,  and  the  setose  cilia. 
The  same  letters  indicate  the  same  parts  in  each  figure. 
a.  The  mantle-lobe  of  the  flattened  or  lower  valve. 
h.  The  mesial  fissure  corresponding  to  the  mesial  process  of  the  valve. 
b'.  The  shell-secreting  edge  prolonged  beyond  the  roots  of  the  cilia, 
c.  The  mantle-lobe  of  the  convex  or  upper  valve. 
d.  d.  The  fringed  margins  of  the  mantle. 
d'.  The  long  setose  cilia, 
d".  The  shorter  cilia, 
e.  The  expanded  peduncle. 
/. /.  The  anterior  pair  of  shell-muscles. 
g.  g.  The  posterior  pair  of  shell-muscles. 
A.  h.  The  anterior  superior  visceral  muscles. 
i.  i.  The  posterior  inferior  visceral  muscles. 
k.  k.  The  fringed  brachia,  or  arms. 
k'.  The  transverse  basis, 
I.  I.  The  free  spiral  extremities. 
m.  m.  The  canals  in  the  fleshy  basis  of  the  arms. 
n.  n.  The  branchial  vessels.    These  are  figured  as  injected  at  fig.  11.  the 
dark  lines  n .  being  the  arteries. 
0.0.  The  two  hearts.    (The  letters  are  placed  in  the  orifices  of  communi- 
cation with  the  veins  of  the  opposite  mantle-lobe.) 
p.p.  The  arteries  going  to  the  liver,  ovary,  &c. 
q.  The  mouth. 
r.  The  oesophagus, 
s.  The  stomach. 
t.  The  intestine. 
u.  The  anus. 
V.  The  liver. 
w.  The  ovary. 
X.  The  subcesophageal  ganglia. 
y.  The  filaments  from  them. 
z.  The  circumscribing  aponeurosis  of  the  viscera. 
14.  Lingula  Audehardii,  Brod. 
15.  The  soft  parts  of  the  same  species,  exposed  by  the  removal  of  the  upper 
VOL.  I.  z 
