ME.  HANCOCK  ON  THE  OEOMNIZATION  OE  THE  BEACHIOPODA. 
819 
'When  in  a highly  developed  state  the  lobes  or  branches  insinuate  themselves  between 
and  around  the  muscles,  so  that  it  is  almost  impossible  to  trace  the  relation  of  these 
organs  to  the  other  parts ; but  when  immature  it  is  very  easy  to  do  so.  The  dorsal 
ovaries  are  then  found  to  be  suspended  by  the  ilio-parietal  bands,  the  ventral  by  the 
continuation  of  these  bands  along  the  free  margins  of  the  pseudo-hearts  or  oviducts.  In 
both  cases  the  attachment  is  along  the  margins  of  the  bands,  which  are  related  to  the 
genitalia  much  in  the  same  manner  as  the  suspending  membrane  is  to  the  genital  bands 
in  Walcllieimia ; and  it  would  seem  that  in  lAngula  the  reproductive  organs  are  really 
developed  between  the  two  layers  composing  the  ilio-parietal  bands.  There  can  be  no 
doubt  that  these  masses,  which  are  of  a reddish-yellow  colour,  are  the  ovaries;  they 
resemble  very  much  in  structure  the  genital  bands  in  the  Terehratulidoe,  and,  as  in 
them,  they  are  found  occasionally  to  contain  eggs,  but  are  frequently  devoid  of  them. 
In  one,  in  which  these  organs  were  filled  with  fully-developed  ova,  the  red  substance 
before  alluded  to  was  present.  In  Lingula^  however,  it  assumes  a different  form : in 
this  it  is  a dendritic  or  branched  organ*,  spread  over  the  external  surface  of  the  ovarian 
masses.  On  the  dorsal  ovaries  the  branches  pass  from  behind  forward  in  two  lateral 
divisions ; on  the  ventral  ones  in  three,  one  being  median,  two  lateral.  The  branches, 
which  are  quite  irregular,  do  not  diminish  in  thickness  towards  their  extremities.  On 
removing  the  thin  transparent  membrane  which  forms  the  dorsal  and  ventral  walls  of 
the  peri\isceral  chamber,  these  dendritic  organs  came  away  with  it,  and  I was  originally 
induced  to  believe  that  they  were  organically  connected  with  it ; but  further  experience 
has  led  to  the  conclusion  that  they  are  really  a portion  of  the  genital  mass,  and  that 
from  the  pressure  of  the  valves,  on  their  being  closed,  they  had  become  accidentally 
adherent  to  the  membrane. 
On  examining  a portion  of  this  branched  organ^  with  the  microscope,  it  was  found  to 
be  composed  of  large  irregular  cells,  somewhat  elliptical  in  form,  and  closely  resembling 
those  of  the  red  substance  in  connexion  with  the  genitalia  in  Waldlieimia.  The  cells, 
however,  in  langida  appeared  to  present  different  stages  of  development,  varying  much 
in  size  and  form.  Some  w’ere  ovate,  others  perfectly  elliptical;  the  larger  ones  were 
pointed  at  both  ends,  and  exhibited  a double  line  in  the  centre,  placed  longitudinally  ; 
while  the  largest,  measuring  Y^ths  of  an  inch  in  length,  were  fusiform,  with  the  extre- 
mities more  or  less  sharply  pointed.  These  corpuscles®  were  filled  with  numerous, 
delicate,  hair-like  bodies,  resembling  spermatozoa.  From  these  facts  it  can  scarcely  be 
doubted  that  the  dendritic  organ  is  the  testis,  and  that  the  fusiform  cells  are  fully 
developed  sperm  at  ophora,  containing  spermatozoa.  It  would  thus  seem  fair  to  con- 
clude that  Langida,  at  least,  is  androgynous ; and  if  the  red  matter  in  connexion  with 
the  genitalia  in  the  articulated  Brachiopods  should  prove  to  be  the  same  as  the  dendritic 
organ  in  the  former,  then  in  them  also  the  sexes  are  combined. 
Professor  Owei^  supposes  that  the  ova,  when  mature,  escape  by  the  dehiscence  of  the 
pallial  membranes*.  So  long  as  no  passage  was  discovered  leading  externally  from  the 
■ Plate  LXIY.  figs.  1,  2.  ^ Plate  LXVI.  fig.  8. 
■*  lutroduction  to  Datidsox’s  ‘British  Eossil  Brachiopoda,’  p.  22. 
^ Plate  LXYI.  figs,  9,  10. 
