100  DE.  T.  WILLIAMS’S  EESEAECHES  OX  THE  STEUCITJEE  AXD  HOMOLOGY 
situated,  remind  one  of  the  trembling  organs  of  Botatoria  connecting  the  two  lateral 
canals  with  the  cavity  of  the  body.”  Letdig*  has  adopted  and  somewhat  extended  this 
homological  idea  of  Von  Siebold.  De  Quatrefages  has  referred  to  these  organs  under 
the  title  of  “ Poches  secretices  venant  s’ouvrir  sur  le  dos,  &c.f”  Both  Henle,  Siebold, 
and  De  Quatrefages  confess  that,  as  yet,  “ no  description  or  figure  has  ever  been  published 
giving  any  idea  of  their  complexity.”  Gegenbauer  J was  the  first  accurately  to  describe 
the  internal  free,  umbrella-shaped,  ciliated  extremity  of  this  organ  in  the  Earth-worm. 
Thus  then,  in  the  genus  Lumbricus,  these  ciliated  tubes  have  been  long  known  to 
exist;  but  as  to  their  minute  anatomy  and  their  real  function,  nothing  but  confusion 
and  contradiction  have  prevailed.  It  should  be  further  understood,  that,  of  the  many 
anatomists  who  have  more  or  less  specially  observed  and  studied  these  organs,  not  one 
has  ever  hinted  (either  directly  or  indirectly)  at  the  relation  in  which  they  stand  to  the 
reproductive  system.  But  the  recent  paper  of  Hering^,  on  the  organs  of  generation  in 
the  Earth-worm,  requires  a special  historical  notice.  In  the  course  of  the  succeeding 
description  it  will  be  seen  that  the  author  differs  from  Herr  Hering  on  the  following 
important  points : — 1st,  as  to  the  size  and  position  of  the  ovaria ; 2nd,  not  only  as  to  the 
distribution  of  the  so-called  vasa  deferential,  but  3rd,  as  to  the  very  fact  of  the  existence 
of  these  ducts  under  any  shape ; and  4th,  and  most  fundamentally,  as  to  the  connexion 
between  the  generative  masses  and  the  “ segmental  organs.”  To  this  latter  point  Hering 
makes  no  reference  whatever.  Lastly,  the  author  is  desirous  to  correct  an  error  into 
Avhich  he  himself  was  drawn  while  writing  his  “ Report  on  the  British  Annelids  ” for  the 
British  Association  (1852).  By  reference  to  that  Report  it  will  be  seen  that,  in  the 
worms  examined  in  that  year,  the  “ segmental  organs  ” in  every  annulus  of  the  body 
were  crowded  with  a vast  multitude  of  the  ova  and  young  of  a certain  species  of  Fit,  art  a. 
By  the  singular  appearance  thus  caused,  the  author  was  induced  to  regard  the  ordinary 
segmental  organs  as  in  truth  nothing  but  ovaries,  looking  upon  the  “ central  reproductive 
masses  ” as  having  experienced  some  special  and  distinctive  development.  Subsequent 
and  most  carefully-conducted  researches  have  convinced  him  that  he  then  mistook  the 
ova  and  young  of  an  Entozoon  infesting  the  Earth-worm  for  those  of  the  animal  itself. 
He  was  lured  into  this  error  in  consequence  of  regarding  the  ordinary  segmental  organs 
of  the  Earth-worm  as  the  real  equivalent  of  the  ovarian  segmental  organ  of  the  Hiru- 
dinse,  and  not  of  those  of  Nais.  And  besides,  at  that  time  the  segmental  organ  of  the 
Earth-worm  was  not  known  in  the  whole  extent  of  its  minute  anatomy. 
Lumbricus  Jordanii\[ , in  the  months  of  July  and  August,  presents  at  a short  distance 
* “Ueber  den  Ban  und  den  systematische  Stellimg  der  Eaderthiere,”  Zeitscbrift  fiir  Wiss.  Zool.  1851. 
t Consult  pi.  21  bis,  Le  Eegne  Animal,  &c.  3me  grande  division,  &c. 
X “ TJeber  die  sogenannteuEespirationsorgane  d.  Eegenwurins,”  in  Siebold  and  Kollikeb’s  Zeitscbrift, 
vol.  iv.  p.  221. 
§ Eavald  Heeixg,  “Zur  Anatomie  und  Physiologie  der  Generationsorgane  des  EegenAvni’ms,”  in  Zeit- 
schrift  fiir  Wiss.  Zool.  1856. 
II  This  is  a minute  terrestrial  Lumbricus.  It  is  found  in  July  and  August  in  the  fine  loamy  earth  of  gar- 
dens. It  is  NOT  the  young  of  the  common  Earth-worm. 
