866 
ME.  HANCOCK  ON  THE  OE&ANIZATION  OE  THE  BEACHIOPODA. 
Fig.  3.  Accessory  pulsatile  vesicle  of  the  ventral  pallial  artery : — a,  artery* ; I,  h,  pallial 
branches  of  ditto ; c,  vesicle. 
Fig.  4.  Ventral  pallial  artery,  with  two  pulsatile  vesicles  attached: — a.  artery;  5,  pallial 
branches  of  ditto ; c,  pulsatile  vesicle ; supplementary  ditto. 
PLATE  LXIV. 
Fig.  1.  Dorsal  view  of  the  animal  oi Lingula  anatina,  the  shell  ha^ing  been  removed: — 
pallial  lobe ; b,  body ; c,  great  pallial  sinuses ; d,  a white  line  running  along 
the  outer  wall  of  ditto,  function  unknown ; e,  e,  orifices,  seen  through  the  pallial 
membrane,  leading  into  the  lateral  branches  of  the  sinuses ; f,  central  branches 
of  ditto ; g,  posterior  branches  of  ditto ; h,  h,  ramuscules  of  posterior  branches ; 
marginal  fold ; j,  extreme  pallial  margin ; Jc,  setae ; Z,  Z,  liver,  seen  through 
the  wall  of  the  perivisceral  chamber ; m,  portion  of  intestine ; n,  dorsal  ova- 
ries ; 0,  0,  testis ; p,  extremities  of  anterior  occlusor  muscles ; g,  ditto  of  poste- 
rior occlusors ; r,  ditto  of  central  adjustors ; s,  ditto  of  external  adjustors ; 
t,  ditto  of  posterior  adjustors ; w,  ditto  of  divaricators ; v,  ditto  of  posterior 
parietals ; w,  edge  of  the  lateral  and  anterior  walls  of  the  body. 
Fig.  2.  Ventral  view  of  the  same;  the  letters  as  in  fig.  1 : — x,  extremity  of  peduncular 
muscle;  y,  oviducts. 
Fig.  3.  View  of  the  pallial  chamber  of  the  same,  the  ventral  pallial  lobe  timied  back : 
— a,  ventral  lobe ; h,  dorsal  ditto ; c,  c,  great  pallial  sinuses ; d,  d,  lateral 
branches  of  ditto ; e,  e,  puckers  of  lateral  branches,  occasioned  by  contraction 
of  the  pallial  margin ; f,f,  terminal  extremities  of  lateral  branches ; g,  g,  cen- 
tral branches  of  the  great  sinuses ; li,  marginal  fold ; Z,  a few  of  the  set® ; j,  ex- 
treme pallial  margin;  k,  brachial  apparatus;  Z,  Z,  cirri;  ??^,  brachial  fold; 
n,  mouth ; o,  o,  external  orifices  of  oviducts. 
Fig.  4.  Dorsal  view  of  the  viscera  of  a young  indmdual  of  L.  anatina,  the  peri^isceral 
chamber  laid  open : — a,  «,  great  pallial  sinuses ; 5,  openings  of  ditto  into  the 
perivisceral  chamber ; c,  posterior  branches  of  ditto ; d,  anterior  occlusors ; 
e,  posterior  ditto ; f,  central  adjustors ; g,  external  ditto ; h,  Ii,  posterior  ditto  ; 
i,  divaricators ; j,  posterior  parietals ; k,k,  anterior  and  lateral  walls  of  the  peri- 
visceral chamber ; Z,  oesophagus ; m,  stomach  ; n,  straight  portion  of  intestine ; 
0,  convoluted  portion  of  ditto ; p,  p,  hepatic  ducts,  the  dorsal  lobes  of  the 
liver  having  been  removed ; q,  dorsal  ovaries ; r,  ilio-parietal  bands ; s,  gastro- 
parietal  ditto ; t,  heart,  contracted ; u,  branchio-systemic  vein ; v,  aorta,  ghing 
off  two  lateral  trunks,  which  divide  into  anterior  and  posterior  branches ; 
IV,  external  arteries  or  blood-channels, — nerves  of  OwEX, — suppljing  anterior 
wall  of  the  perivisceral  chamber ; x,  internal  ditto. 
Fig.  5.  Ventral  view  of  the  viscera  of  the  same ; the  letters  up  to  k correspond  to  those 
