ME.  HANCOCK  ON  THE  OEOANIZATION  OF  THE  BEACHIOPODA. 
863 
brachial  canal a,  walls  of  ditto ; I,  grooved  ridge ; c,  brachial  fold ; d,  cirri ; 
e,  efferent  brachial  canal,  the  orifices  leading  into  the  cirri  appearing  through 
its  wall  in  a double  series ; f,  afferent  brachial  channel,  charged  with  coagu- 
lated pellets  of  blood-corpuscles. 
Fig.  11.  Pellets  of  coagulated  blood-corpuscles  from  the  tissue  of  the  brachial  grooved 
ridge. 
Fig.  12.  One  of  the  smaller  spicula  from  the  mantle  of  T.  caput-serpentis. 
PLATE  LXI. 
Fig.  1.  General  view  of  the  viscera  oi  Hkynclionella  psittacea,  seen  from  behind,  the 
umbonal  portions  having  been  removed: — a,  dorsal  pallial  lobe;  h,  ventral 
ditto ; c,  c,  anterior  wall  of  perivisceral  chamber ; d,  anterior  occlusor 
muscles ; d',  d',  posterior  ditto ; e,  e,  ventral  extremities  of  divaricators ; 
fif,  ditto  of  ventral  adjustors;  g,  portion  of  the  oesophagus;  A,  stomach,  ex- 
hibiting two  of  the  orifices  of  the  hepatic  ducts,  the  left  lobes  of  the  liver 
ha\ing  been  removed ; ^,  right  anterior  and  posterior  hepatic  lobes ; in- 
testine ; A,  bulbous  termination  of  ditto ; I,  dorsal  mesentery ; m,  portion  of 
ventral  ditto ; w,  w,  lateral  gastro-parietal  bands ; o,  central  gastro-parietal 
band;  p^  p,  ilio-parietal  bands;  heart  in  contracted  state;  r,  aorta,  giving 
off  two  lateral  branches ; 5,  s,  dorsal  pallial  or  genital  arteries ; t,  t,  ventral 
ditto ; u,  u,  u,  u,  pulsatile  vesicles  in  connexion  with  the  pallial  arteries ; 
V,  V,  V,  V,  dorsal  and  ventral  pairs  of  oviducts ; w,  w,  w,  w,  genital  organs  lying 
unthin  the  pallial  sinuses ; x,  x,  muscular  bands  or  ties  passing  between  the 
walls  of  the  sinuses ; y,  sheaths  of  the  crural  processes  or  oral  laminse ; 
z,  orifices  leading  into  ditto ; z',  portions  of  the  dorsal  adjustor  muscles. 
Fig.  2.  Side  view  of  the  riscera  of  the  same: — a,  anterior  wall  of  perivisceral  chamber; 
b,  b,  brachial  organs ; c,  ventral  terminations  of  occlusor  muscles ; c',  c\  dorsal 
terminations  of  anterior  and  posterior  occlusors ; f/,  d,  divaricators,  the  left  one 
cut  through ; d\  ventral  wall  of  perivisceral  chamber ; e,  peduncle ; e',  capsule 
of  ditto ; y,  peduncular  muscle ; g,  one  of  the  dorsal  adjustors ; h,  one  of  the 
ventral  ditto ; ?,  oesophagus ; stomach,  exhibiting  the  two  openings  of  the 
left  hepatic  ducts,  the  liver  having  been  removed  from  this  side ; A,  right  lobes 
of  the  liver ; /r',  posterior  lobe ; A",  anterior  ditto ; /,  dorsal  mesenteric  mem- 
brane ; m,  m,  ventral  ditto ; n,  lateral  gastro-parietal  band ; o,  central 
ditto  ; p,  p^  ilio-parietal  bands ; heart ; r,  branchio-systemic  vein ; s,  aorta ; 
t,  f',  dorsal  and  ventral  pallial  or  genital  arteries ; ii,  right  ventral  oviduct ; 
u',  portion  of  left  ditto  cut  through ; v,  oesophageal  ganglia ; w,  sheath  of 
crural  process  or  oral  lamina;  x,  orifice  leading  into  ditto ; y,  portion  of  ditto 
of  the  opposite  side ; z,  terminal  sac  of  the  left  great  brachial  canal ; z\  ditto 
of  the  right  or  opposite  arm,  seen  through  the  mesenteric  membrane. 
MDCCCLVIII.  5 u 
