C    213  ] 
XXIV.  On  the  Structure  of  the  Heart  in  the  Perennibranchiate  Batrachia.  By  Richard 
Owen,  Esq.,  F.Z.S.,  Assistant  Conservator  of  the  Museum  of  the  Royal  College  of  Sur- 
geons  in  London. 
Communicated  April  22,  1834. 
the  Reptilia  form  the  transition  between  those  classes  of  Vertebrata  that  possess 
the  highest  and  lowest  degrees  of  the  respirator}''  function,  they  differ  considerably 
among  themselves  both  in  the  extent  and  mode  of  respiration,  and  present  correspond- 
ing variations  in  the  external  form  and  internal  structure  of  the  heart.  This  part  of 
their  anatomy  has  therefore  been  a  subject  of  peculiar  interest,  not  only  from  its  phy- 
siological relations,  but,  as  Mr.  Hunter  first  observed',  from  its  varieties  of  structure 
exhibiting  as  permanent  conditions  some  of  the  transitional  states  which  the  heart  of 
the  warm-blooded  Vertebrata  successively  assumes  in  its  progress  towards  perfection. 
The  knowledge  of  these  different  structures  has,  however,  been  slowly,  and  much  of 
it  recently,  acquired.  Linnseus  attributed  to  the  whole  of  his  class  Amphibia  a  simple 
bipartite  heart,  as  in  Fishes,  "Cor  uniloculare  uniauritum."  But  prior  to  the  publi- 
cation of  the  12th  edition  of  the  '  Systema  Naturse',  the  more  complex  structure  of  the 
Tortoise's  heart  had  been  described  by  Duverney  and  Mery  in  the  '  Memoires  de  I'Aca- 
demie  des  Sciences '2,  as  well  as  by  Bussieres  in  the  27th  volume  of  the  '  Philosophical 
Transactions''^.  Hasselquist  had  also  pointed  out  the  superior  organization  of  the  heart 
of  the  Crocodile^.  Daudin^,  therefore,  in  his  systematic  work  on  Reptiles,  admits  the 
double  auricle  in  the  heart  of  the  Chelonia  and  Sauria,  but  characterizes  the  Ophidia,  as 
well  as  Batrachia,  as  having  the  simpler  bipartite  form  of  the  organ ;  and  this  is  sanc- 
tioned by  Blumenbach  as  far  as  regards  the  Serpents  of  Germany.  Cuvier  and  Meckel, 
however,  more  correctly  attribute  to  the  Ophidia  a  heart  with  two  separate  auricles ; 
but  in  their  latest  writings''  they  state  the  single  auricle  to  be  common  to,  and  charac- 
teristic of,  the  Batrachian  order  of  Reptiles. 
Meckel,  indeed,  after  premising  that  the  Batrachia  have  the  simplest  form  of  heart, 
"  which  consists  uniformly  of  but  one  auricle  and  ventricle,  of  which  the  first  receives 
the  blood  by  many  trunks  from  the  body  and  lungs  at  the  same  time,"-^  afterwards 
'  On  the  Blood,  p.  135.  For  the  years  1676,  1703. 
3  For  the  year  1712.  p.  172.  The  figures  given  by  this  author  appear  to  me  to  be  more  faithful,  and  from 
the  mode  of  dissection  employed  more  intelligible,  than  those  of  Mery. 
Itin.  JEg}-])t.  et  Palest.,  p.  293.  »  Hist.  Nat.  des  Reptiles,  torn.  i.  p.  335. 
^  Cuvier,  Regne  Anim.,  nouv.  ed.,  torn.  ii.  p.  101. — Meckel,  Vergl.  Anat.,  band  v.  p.  215. 
'  "  Die  Batrachier  haben  die  einfachste  Herzform.  Das  Herz  besteht  sehr  allgemein  nur  aus  einer  Vorkam- 
mer  und  einer  Kammer,  von  denen  die  erste  das  Blut  durch  mehrere  Stiimme  aus  den  Korper  und  den  Lungen 
zugleieh  aufnimmt." — Loc.  cit.,  p.  215. 
2  F  2 
