146 
MR.  R.  OWEN  ON  THE  ANATOMY  OF  THE  BRACHIOPODA. 
simillima).  He  enumerates  three  pairs  of  muscles  belonging  to  the  shell,  and  notices 
the  situation  of  the  mouth  and  stomach,  but  not  that  of  the  anus.  The  cloak,  probably 
from  its  close  adherence  to  the  valves,  he  calls  periosteum. 
Another  account  of  the  organization  of  Terehratula  is  given  by  M.  de  Blainville  in 
the  '  Dictionnaire  des  Sciences  Naturelles'^  After  noticing  the  symmetrical  character 
of  the  soft  parts,  and  their  general  relation  to  the  valves,  he  proceeds  to  speak  of  the 
arms,  and,  preferring  the  opinion  of  Pallas  to  that  of  Cuvier,  considers  them  as  the 
respiratory  organs.  With  respect  to  the  intestinal  canal  and  liver,  nothing  is  added  to  the 
description  given  by  Pallas.  The  branchia  M.  de  Blainville  supposes  to  have  the  power 
of  projecting  outwardly,  though  not  to  the  same  extent  as  the  arms  in  Lingula,  and  thus 
to  contribute  to  open  the  shell.  Of  the  muscular  apparatus  of  Terehratula  he  conjectures 
part  to  belong  to  the  visceral  mass,  and  was  unable  to  distinguish  more  than  two  pairs 
belonging  to  the  valves.  The  extremities  of  both  these  pairs  he  describes  as  attached  to 
the  valves,  but  considers  it  very  probable  that  some  of  the  fibres  may  pass  through  the 
orifice  of  the  perforated  valve,  or  be  attached  to  the  membrane  which  closes  that  orifice. 
From  the  particulars  he  was  enabled  to  ascertain  concerning  the  organization  of  Tere- 
hratula, and  with  the  conviction  that  the  hranchics  are  not  attached  to  the  mantle,  he 
considers  that  genus  as  intermediate  to  the  true  Palliohranchiata  {Lingula,  e.  g.,)  and 
the  Lamellihranchiate  Bivalves. 
In  the  latest  edition  of  the  '  R^gne  Animal'  Cuvier  retains  his  original  opinion 
respecting  the  nature  of  the  fringed  or  pinnate  labial  processes  of  Terehratula,  still 
calling  them  arms :  his  description,  however,  of  the  muscles  of  the  valves  is  liable  to 
the  same  objection  as  those  of  the  preceding  authors,  since,  with  the  exception  of 
one  pair,  they  do  not  go  from  one  valve  to  the  other.  He  describes  the  ovaries  as 
ramified  productions  adherent  to  each  valve,  but  is  doubtful  as  to  the  position  of  the 
hranchi(B. 
On  account  of  the  peculiar  interest  attached  to  this  genus,  both  from  its  anatomical 
and  geological  relations,  and  from  the  contrariety  of  opinions  entertained  respecting 
some  of  its  most  important  organs,  I  felt  considerable  pleasure  at  receiving  from 
Mr.  Cuming  a  small,  recent,  and  well  preserved  specimen  of  Ter.  Chilensis,  Brod. ; 
and  I  am  much  gratified  in  having  this  opportunity  of  acknowledging  the  liberality  with 
which  he  has  submitted  to  me  the  numerous  specimens  of  the  animals  of  rare  and  in- 
teresting species  of  shells  collected  by  him. 
From  observations  on  the  young  specimen  of  Ter.  Chilensis,  I  was  at  first  inclined 
to  suppose  that  the  coagulated  contents  of  the  branchial  veins  might  have  been  mis- 
taken for  the  ova  ;  but  having  subsequently  received  three  full-grown  specimens,  con- 
taining two  distinct  species  of  Terehratula^,  through  the  kindness  of  Capt.  P.  P.  King, 
and  having  more  recently  dissected  a  well  preserved  Ter.  psittacea,  Brug.,  taken  by 
'  Tom.  liii.  p.  130. 
2  Ter.  dorsata,  Brug.,  and  Ter.  SowerUi,  King,  Zool.  Joum,,  vol.  v.  p.  338, 
