[    145  ] 
XVIIT.  On  the  Anatomy  of  the  Brachiopoda  of  Cuvier,  and  more  especially  of  the  Genera 
Terebratula  and  Orbicula.  By  Richard  Owen,  Esq.,  F.Z.S.,  Assistant  Conservator 
of  the  Museum  of  the  Royal  College  of  Surgeons  in  London. 
Communicated  November  26,  1833. 
It  is  to  Cuvier  that  we  are  indebted  for  the  knowledge  of  that  interesting  form  of  the 
respiratory  organ  of  the  Bivalve  Mollusks,  by  which  the  mantle,  in  addition  to  its  se- 
creting the  shelly  defence  of  the  viscera,  and  constituting  their  immediate  covering,  is 
made  subservient  also  to  the  renovation  of  the  circulating  fluids.  The  dissection  of 
Lingula  anatina,  Brug.,  which  first  brought  to  hght  this  structure,  is  among  the  early 
labours  of  that  great  anatomist,  and  forms  the  subject  of  his  first  paper  in  the  '  Annales 
du  Museum.'  He  observed  in  Lingula  that  in  the  situation  occupied  by  the  hranchice  in 
ordinary  Bivalves,  there  were  instead  two  fringed  and  spirally  disposed  arms,  and  that 
the  hranchice  themselves  were  arranged  in  oblique  parallel  lines  along  the  internal  sur- 
face of  both  lobes  of  the  mantle ;  that  the  lobes  of  the  mantle  were  further  charac- 
terized by  large  vessels  returning  the  blood  from  the  respiratory  organs ;  and  that 
these  vessels  (the  branchial  veins)  terminated  in  two  systemic  hearts,  which  were 
symmetrically  disposed,  thus  forming  a  new  type  of  circulation,  corresponding  to  the 
modification  of  the  respiratory  system. 
For  the  Molluslts  possessing  these  important  modifications  of  structure,  Cuvier 
founded  a  distinct  class,  which,  according  to  his  system  of  orismiology  for  that  di- 
vision of  the  animal  kingdom,  he  denominated  Brachiopoda,  considering  the  fringed 
arms  as  being  in  place  of  the  foot  in  the  Cockle,  Muscle,  &c. 
From  the  analogy  of  Terebratula  to  Lingula  in  its  pedicellate  mode  of  attachment  to 
foreign  substances,  and  from  such  notices  of  the  construction  of  the  soft  parts  as  he 
had  then  met  with,  he  concluded  that  its  organs  of  respiration  were  similarly  situated, 
and  that  what  had  been  taken  for  hranchicp,  by  Lamanon'  and  Walsh  2,  were  in  fact  the 
analogues  of  the  fringed  arms  of  Lingula. 
It  is  remarkable  that  Cuvier  in  no  part  of  his  Memoir,  nor  in  either  of  the 
editions  of  the  '  Regne  Animal,'  should  allude  to  the  concise  description  which  Pallas 
has  given  of  the  animal  of  Terebratula  in  the  '  Miscellanea  Zoologica'^.  Under  the  old 
name  of  Anomia,  which,  since  the  Linnsean  character  is  applicable  only  to  the  modern 
Terebratulce,  ought  to  have  been  retained  for  them,  Pallas  notices  the  limited  situation 
of  the  viscera.  He  describes  the  arms  with  his  usual  minuteness  and  accuracy,  but 
considers  them  as  hranchice,  comparing  them  to  those  of  a  fish  {piscium  hrancldis 
'  Voyage  de  la  Perouse,  p.  146.  -  Naturforsch.,  torn.  iii.  p.  88.  ^  P.  182.  (Anomiarum  Biga.) 
