or  THE  EEPEODUCTIVE  OEOANS  OE  THE  ANNELIDS. 
Ill 
the  reproductive  rings  terminate  anteriorly,  so  that  the  first  and  the  last  segments  in  this 
region  are  testicular,  the  three  intermediate  ones  being  ovarian. 
The  ovaria  of  laimbricus  are  much  more  transient  in  duration  than  the  testes.  The 
latter  in  a certain  condition  are  always  present  at  every  season  of  the  year ; the  former 
only  in  the  summer  months.  The  ova,  while  yet  in  the  ovaria,  are  beautifully  clear  trans- 
parent cells.  In  August  and  September  they  seem  to  consist  of  nothing  but  germinal 
vesicles ; afterwards  appear  the  germinal  spots,  and  then  the  rudimentary  vitellus.  It  is 
at  a subsequent  stage,  just  before  their  extrusion  from  the  body,  that  they  become 
covered  with  a cocoon  or  characteristic  capsule,  each  capsule  containing  many  ova.  This 
capsule  is  a compound  of  chalk  and  mucus.  The  source  of  the  chalk  has  never  yet  been 
described.  In  the  median  line  between  the  ovaria  there  are  situated  two  or  more  glan- 
dular bodies  (fig.  6 the  contents  of  which  under  the  microscope  prove  to  consist  of 
nothing  but  carbonate  of  lime*. 
Both  in  the  ovarian  and  testicular  segments,  there  are  sacculi  attached  to  the  bases  of 
the  segmental  organs,  which  in  the  former  case  serve  as  receptacles  for  the  ova  {vitel- 
laria\  and  in  the  latter  as  receptacles  for  the  semen.  In  one  case  the  ova  acquire  their 
calcareous  capsules ; in  the  other  the  sperm-cells  become  developed  into  active  sperma- 
tozoa. These  membranous  sacculi  have  long  been  known  to  anatomists.  They  were 
described  in  the  author’s  Report  (1854)  on  the  Annelids,  in  the  Transactions  of  the 
British  Association. 
The  preceding  account  embodies  a brief  outline  of  the  author’s  researches  into  the 
reproductive  organs  of  the  Annelids. 
They  justify  the  following  general  conclusions : — 
1.  That  the  ovaria  and  testes  in  Lumbricus  terrestris  (vel  communis)  are  centralized 
together  in  one  special  region  of  the  body. 
2.  That  the  ovaria  and  testes  are  situated  in  different  annuli  and  attached  to  different 
“ segmental  organs.” 
3.  That  the  segmental  organs  of  the  male  and  female  annuli  are  identical  in  shape, 
size  and  structure. 
4.  It  follows  that  the  ducts  leading  from  each  ovary  and  testis,  being  identified  respect- 
ively with  the  cihated  tubes  of  their  own  rings,  open  externally  by  distinct  orifices. 
This  conclusion,  if  true,  renders  it  impossible  that  Heeing’s  observations  can  be  correct. 
At  this  place  it  is  interesting  to  inquire  what  can  be  the  meaning  of  the  increase  of 
size  which  takes  place  in  the  ciliated  tubes  or  “ segmental  organs  ” which  are  limited  to 
the  generative  region,  as  compared  with  those  of  the  ordinary  segments  of  the  body. 
♦ The  egg-capsules  of  Lumbricus  agricola  have  been  well  described  by  Dr.  Geo.  Meissxer  (Zeitsch.  f. 
Wiss.  Zool.  14  Sept.  1854).  He  observes,  “ Der  Eegenvmrm  legt,  wie  bekannt  ist,  Eierkapseln.  Diese 
sind  bei  den  verschiedenen  Arten  von  verscbiedener  Gestalt  und  Grbsse ; die  Grossten  sind  die  citronen- 
formigen  Kapseln  des  L.  agricola  (vieUeicht,”  he  observes,  “mit  Ausnahme  derjenigen  L.  gigas,  Dtjges, 
die  ich  nicht  kenne).  In  jeder  Eierkapsel  befinden  sich  in  der  Eegel  mehre  Eier  oder  Hotter  in  einer  miich- 
weissen  zahen  Eliissigkeit  suspendirt,”  &c.  &c.  He  does  not,  however,  allude  to  the  chalk-secreting  glands. 
q2 
