or  THE  EEPEODUCTIVE  OEGANS  OP  THE  ANNELIDS. 
129 
Let  us  now  proceed  to  trace  the  segmental  organ  throughout  other  and  still  more 
remarkable  variations  of  type,  preserving  nevertheless  its  homological  identity. 
De  Quatrefages  has  devoted  a separate  memoir*  to  the  publication  of  the  results  of 
his  researches  into  the  organization  of  the  family  of  the  Chloreemea  (of  Dujardin).  His 
investigations  seem  to  have  been  most  elaborate,  and  yet  De  Quatrefages  has  been 
entirely  misled  in  reference  to  the  reproductive  system  of  this  family.  He  thus  expresses 
himself: — “ Je  n’ai  rien  vu  dans  les  Chloremes  qui  put  etre  regarde  comme  un  organe 
reproducteur,  ce  qui  tient  sans  doute  a lepoque  de  mes  observations,  qui,  par  deux  fois, 
ont  eu  lieu  en  automne.  Toutefois  je  ne  puis  croire  encore  avec  M.  Costa  que  les 
sexes  soient  reunis,  soit  chez  les  Chloremes,  soit  chez  un  genre  quelconque  de  cette 
famille.  Les  organes  que  ce  naturaliste  a regardes  comme  des  testicules  occupent  ex- 
actement  la  meme  position  que  les  glandes  salivaires  que  j’ai  decrites,  et  sont  representes 
par  I’auteur  lui-meme  comme  tenant  a I’cesophage.  De  nouvelles  observations  bien  pre- 
cises me  paraitraient  done  necessaires.  Dans  le  cas  ou  le  fait  annonce  par  M.  Costa 
viendrait  a etre  confirme,  il  en  resulterait  que  les  Chloremiens  devraient  entrer  dans  le 
groupe  des  Anneles  dioiques  ou  ils  representeraient  les  Annelides  tubicoles,  comme  les 
Lombrics  et  les  Nais  representent  les  Annelides  errantes.” — Loc.  cit.  This  is  all  that 
occurs  in  the  special  memoir  of  the  French  anatomist  with  respect  to  the  reproductive 
system ; such  an  account  can  hardly  be  said  to  be  either  consistent  or  intelligible.  But 
De  Quatrefages  himself  admits  that  new  observations.  Men  precises,  on  this  subject  are 
necessary.  The  author  of  this  memoir  hopes  that  this  desideratum  will  now  be  supplied. 
Chlorcema  Bujardinii  is  very  frequently  met  wdth  on  the  Welsh  coast  of  the  Bristol 
Channel.  If  the  principle  be  conceded  that  the  segmental  organ,  with  its  associated 
germinal  masses,  of  this  Annelid,  may  be  received  as  expressive  of  a law  applicable  to 
the  entire  class,  points  of  clear  morphological  meaning  will  now  be  placed  beyond  the 
possibihty  of  controversy.  In  order  to  verify  by  observation  the  facts  now  to  be  nar- 
rated, it  is  necessary  that  specimens  in  a suitable  condition  should  be  examined  at  two 
different  seasons,  -viz.  in  May  and  June,  and  in  August  and  September.  In  the  indi- 
viduals examined  during  the  former  months,  the  fact  will  most  certainly  and  easily  be 
established,  that  the  ova  in  the  female,  and  the  sperm-cells  in  the  male,  are  most  clearly 
and  distinctly  contained  loithin  the  membranous  limits  of  the  segmental  organ  f.  In 
those  observed  later  in  the  season  (August  and  September),  the  state  of  things  deli- 
neated in  fig.  23,  Plate  VIII.,  will  almost  constantly  be  noted;  viz.  that  in  which  the 
ovules  and  sperm-cells  have  escaped  from  the  segmental  organ  and  accumulated  in  large 
irregular  masses  (A  e e e,  female)  (B  d d,  male),  which  float  in  the  fluid  of  the  general 
cavity,  but  which  are  bounded  by  a distinctly  limiting  membrane.  This  membrane  it  is 
which  prevents  the  germinal  products  from  entering  directly  into  the  free  space  of  the 
perigastric  chamber ; and  observation  proves  that  at  no  stage  of  their  development  do 
* Ann.  d.  Sc.  Nat.  tom.  xii.  1819. 
t Amongst  the  original  drawings  which  accompanied  this  paper  to  the  Eoyal  Society,  were  two  illustrating 
the  conditions  referred  to  in  the  text. 
