864 
IIR.  HANCOCK  ON  THE  OEGANIZATION  OF  THE  BEACHIOPODA. 
Fig.  3.  Side  view  of  the  stomach  and  liver: — «,  cardiac  extremity  of  stomach;  b,  pyloric 
ditto ; c,  transverse  ridge,  to  which  the  gastro-parietal  bands  are  attached  ; 
d,  d,  hepatic  ducts ; e,  e,  branched  ceeca  composing  the  liver. 
Fig.  4.  Stomach  laid  open : — a,  oesophagus ; b,  intestine ; c,  c,  folds  of  the  lining  mem- 
brane ; d,  d,  orifices  of  hepatic  ducts ; e,  groove  corresponding  to  the  external 
transverse  ridge. 
Fig.  5.  Portion  of  epithelium  jfi’om  the  mantle  of  W.  australis^  much  magnified. 
Fig.  6.  Portion  of  epithelium  lining  the  great  brachial  canal. 
PLATE  LXII. 
Fig.  1.  Diagram  of  the  muscular  system  of  W.  australis: — a,  dorsal  valve;  b,  ventral 
ditto ; c,  peduncle ; d,  capsule  of  ditto ; e,  calcareous  loop ; f,  hinge-plate ; 
g,  alimentary  tube ; h,  heart ; anterior  occlusors ; j,  posterior  ditto ; k,  diva- 
ricators;  accessory  ditto ; m,  dorsal  adjustors;  w,  ventral  ditto;  o,  pedun- 
cular muscle ; p,  cardinal  process. 
Fig.  2.  Diagram  exhibiting  muscular  arrangement  of  W.  cranium : — a,  dorsal  valve ; 
ventral  ditto ; c,  peduncle ; d,  capsule  of  ditto ; e,  calcareous  loop ; f,  dental 
socket ; g,  g^  anterior  and  posterior  occlusors  of  the  right  side,  those  of  the  left 
having  been  removed ; A,  A,  areas  of  attachment  of  dorsal  extremities  of  the  left 
occlusors ; i, divaricators  and  their  accessories  combined ; j,  ventral  adjustors ; 
k,  k,  dorsal  ditto ; I,  peduncular  muscle ; m,  cardinal  process. 
Fig.  3.  Diagram  of  the  muscular  system  of  Lingula  anatina: — a,  dorsal  valve;  5,  ventral 
ditto ; c,  c,  alimentary  tube,  the  convoluted  portion  of  intestine  removed ; 
d,  heart ; e,  e,  a double  line,  indicating  the  margin  of  the  lateral  and  anterior 
walls  of  the  perivisceral  chamber ; f \ area  of  attachment  of  the  posterior- 
parietal  muscles ; g,  anterior  occlusors ; A,  posterior  ditto ; divaricators ; 
j,  central  adjustors ; k,  external  ditto ; I,  I,  I,  posterior  ditto ; m,  muscular 
cylinder  of  peduncle  deprived  of  its  horny  sheath ; 9i,  peduncular  muscle. 
Fig.  4.  Divaricator  muscles  of  variety  of  W.  australis,  shoufing  them  combined  -vrith 
their  accessories portion  of  peduncular  capsule ; b,  peduncidar  muscle  ; 
c,  portion  of  ventral  adjustor;  d,  portion  of  dorsal  ditto;  e,  portion  of  occlu- 
sors ; f,  divaricators ; g,  portion  of  ditto,  corresponding  to  the  accessory  diva- 
ricators ; h,  extremities  attached  to  cardinal  process. 
Fig.  5.  Ventral  extremity  of  anterior  occlusor  of  W.  australis: — a,  fleshy  contractile 
portion ; b,  b,  white  tendinous  ditto. 
Fig.  6.  A little  of  the  fleshy  portion  of  the  posterior  occlusor,  much  magnified,  exhibit- 
ing transverse  striee. 
Fig.  7.  A fibre  and  two  fibrillse  of  same,  more  highly  magnified : — a,  fibre;  b,b,  fihrilhn, 
exhibiting  cell-like  structure. 
Fig.  8.  A little  of  the  fleshy  portion  of  one  of  the  non-striated  muscles,  much  magnified. 
