ME.  HANCOCK  ON  THE  OEOANIZATION  OF  THE  BEACHIOPODA. 
855 
PLATE  LIV. 
Fig.  1.  General  view  of  the  viscera  of  variety  of  W.  australis^  seen  from  above : — a,  por- 
tion of  dorsal  pallial  lobe ; 5,  5,  great  inner  pallial  sinuses,  that  on  the  left  laid 
open ; h\  outer  ditto ; c,  genitalia ; peduncle ; e,  capsule  of  ditto  ; /*,  f,  an- 
terior occlusors;  f,f  \ posterior  ditto,  the  left  one  partially  removed  to  ex- 
hibit gastro-parietal  band ; divaricators ; A,  A,  dorsal  adjustors  cut  through ; 
*,  ventral  adjustors ; j,  ventral  extremities  of  occlusors ; Jc,  stomach ; I,  intes-^ 
tine ; m,  right  lobes  of  the  liver,  seen  through  the  wall  of  the  perivisceral 
chamber ; m',  portion  of  anterior  hepatic  lobe  of  left  side ; n,  n,  hepatic  ducts 
of  anterior  and  posterior  lobes  of  the  same  side ; o,  dorsal  mesentery ; p,  one 
of  the  lateral  gastro-parietal  bands ; central  gastro-parietal  band ; r,  heart, 
dilated;  s,  ventral  accessory  pulsatile  vesicles;  s',  one  of  the  dorsal  ditto, 
contracted ; branchio-systemic  vein ; u,  dorsal  pallial  artery ; v,  ventral  ditto  ; 
w,  peduncular  artery;  x,  posterior  extremities  of  ventral  genitalia;  y,  lami- 
nated portion  of  oviducts ; 2,  orifice  leading  into  ditto. 
Fig.  2.  General  \dew  of  the  viscera  of  W.  cranium^  seen  from  above;  the  letters  agree 
with  those  of  fig.  1 up  to  and  including  I : — m,  hepatic  lobes ; w,  dorsal  me- 
sentery ; 0,  lateral  gastro-parietal  bands ; p,  ilio-parietal  ditto ; heart  in 
contracted  state ; r,  branchio-systemic  vein ; s,  s,  dorsal  pallial  artery ; t,  ven- 
tral ditto ; u,  peduncular  artery,  running  along  margin  of  ventral  mesentery ; 
V,  posterior  extremity  of  right  dorsal  genital  organ ; w,  posterior  extremities 
of  ventral  genitalia ; x,  laminated  portion  of  oviducts. 
Fig.  3.  Intestine  of  the  same,  enlarged: — a,  upper  extremity;  h,  posterior  csecal  extremity; 
c,  c,  portions  of  oviducts ; d,  ventral  mesentery ; e,  e,  thickened  ridges  of  ditto  ; 
f,  peduncular  artery. 
Fig.  4.  Csecal  or  lower  extremity  of  the  same  intestine  seen  in  the  compressor : — «,  walls 
of  intestine ; h,  caiity  of  ditto  ; c,  ventral  mesentery ; d,  d,  thickened  ridges  of 
ditto. 
Fig.  5.  Transverse  section  of  intestine  a little  below  the  stomach: — a,  a,  portions  of  ilio- 
parietal  bands ; b,  portion  of  ventral  mesentery ; c,  external  sheath  of  intes- 
tine ; d,  muscular  layer  of  ditto ; e,  e,  folds  of  mucous  membrane. 
Fig.  6.  Another  section  of  the  same  intestine  a little  lower  down. 
Fig.  7.  A third  section  a little  above  caecal  extremity ; the  letters  of  the  two  last  corre- 
spond to  those  of  fig.  5. 
Fig.  8.  Side  view  of  lower  portion  of  intestine  of  W.  australis : — «,  a,  ventral  mesentery ; 
h,  lacunes  or  blood-channels,  between  the  layers  of  ditto ; c,  csecal  extremity 
of  intestine ; d,  ridges  in  mesentery. 
Fig.  9.  Csecal  extremity  of  intestine  seen  through  the  dorsal  wall  of  the  perivisceral 
chamber : — a,  portion  of  dorsal  wall  of  chamber ; h,  bases  of  the  pallial  cseca ; 
c,  imperforate  extremity  of  intestine. 
Figs.  10,  11.  Transverse  sections  of  intestine:  letters  as  in  fig.  5. 
MDCCCLVIII.  5 T 
