818 
MR.  HANCOCK  ON  THE  ORGANIZATION  OE  THE  BRACHIOPODA. 
to  be  composed  almost  entirely  of  minute,  clear  granules.  Tbe  red  substance  is  likewise 
found  to  be  made  up  of  large,  irregular  cells,  inclining  to  oval,  ver\’  variable  in  size,  and 
without  any  apparent  nucleus. 
In  JK  cranium  the  genitalia ' are  arranged  precisely  as  in  W.  australis,  only  the  bands 
do  not  extend  so  far  fonvard,  and  are  of  a pale  yellow  colour.  The  red  matter  is  also 
present,  sprinkling  the  surface  with  distant,  round  spots.  The  bands  are  very  finely 
granular,  and  in  no  instance  have  I detected  eggs  in  them.  It  is  therefore  probable 
that  those  examined  were  out  of  season. 
T.  caput-serpentis  exhibits  a somewhat  different  arrangement  of  these  organs^.  In  this 
species  they  are  placed  in  large  sinuses  situated  in  the  pallial  lobes,  one  at  each  side. 
These  sinuses  are,  however,  nothing  more  than  the  enlarged  trunks  of  the  so-called 
pallial  vessels  or  great  pallial  sinuses.  They  are  four  in  number,  two  in  each  lobe ; and 
the  genital  band  which  is  placed  within  them  forms  a thick,  convoluted  layer,  with 
small  spaces  between  the  folds.  The  convolutions  are  grooved  throughout  on  the  under 
surface,  and  the  suspending  or  genital  membrane^  passes  into  the  groove,  as  it  does  in 
Waldheimia ; and  here,  consequently,  it  forms  a complete  network.  This  layer  is  of  a 
rosy  salmon-colour  when  the  animal  is  alive,  but  in  spuit-specimens  is  yellow.  The 
walls  of  the  sinuses  are  held  together  by  numerous  muscular  ties,  which  pass  directly 
from  the  one  to  the  other,  through  the  spaces  left  between  the  convolutions  of  the  band. 
The  ventral  sinuses  are  the  larger.  When  in  an  immature  state  the  bands  appear 
to  be  composed  of  rather  large,  circular  vesicles,  withm  which  the  eggs  are  probably 
developed. 
The  reproductive  organs  have  much  the  same  disposition  in  EhyncJionella  psittacea ; 
but  the  dorsal  genital  sinuses  are  not  connected  with  the  so-called  vascular  trunks,  while 
the  ventral  are.  The  genital  band\  too,  which  is  yellow,  is  much  more  closely  convo- 
luted, having  sometimes  almost  the  appearance  of  being  fused  into  one  mass,  the  inter- 
stices being  just  sufficient  to  permit  the  passage  of  the  muscular  ties,  which  are  stout, 
and  are  arranged  in  imperfect  longitudinal  and  diagonal  Imes.  These  ties  give  a granu- 
lated or  pitted  appearance  to  the  ovarian  impression  in  the  shell,  and  are  worthy  of  the 
attention  of  the  palaeontologist.  The  sinuses  are  limited  to  the  posterior  half  of  the 
lobe,  while  in  T.  caput-serpentis  they  advance  much  beyond  the  centre.  The  genitalia 
in  E.  nigricans  are  arranged  in  precisely  the  same  manner  as  in  E.  psittacea. 
\\\  Ungida.,  the  only  form  of  the  unarticulated  Brachiopods  in  which  1 have  examined 
the  reproductive  organs®,  they  are  withdrawn  altogether  from  the  mantle,  and  are  placed 
in  the  perivisceral  chamber,  as  they  are  stated  to  be  in  Eiscina.  In  the  former  these 
organs  are  very  bulky,  occupying  a very  large  portion  of  the  chamber ; they  lie  for  the 
most  part  behind  the  liver,  and,  as  has  been  already  stated,  surround  the  alimentary 
tube ; they  form  four  irregularly  lobulated  or  branched  masses,  two  above  and  two  below 
the  tube ; these  pairs  may  be  denominated  respectively  the  dorsal  and  ventral  ovaries. 
' Plate  LIII.  figs.  3,  4.  Plate  LIII.  figs.  1,  2.  ^ Plate  LY.  fig.  2. 
' Plates  LX.  figs.  1,  2,  3 ; LXI.  fig.  1.  ^ Plates  LXIV.  figs.  1,  2,  4,  5 ; LXY.  fig.  3. 
