62 
this  organ,  published  by  Beddard  (Proc.  Zool.  Soc.  1890,  pl.  V,  fig.  11) 
is  inaccurate  and  probably  has  been  made  after  a  badly  preserved  worm. 
The  number  of  setae  in  each  segment  is  much  greater  than  in 
P.  indica  ;  in  the  segments,  lying  directly  in  front  of  the  clitellum  and 
behind  it,  I  counted  90  of  them  in  a  row.  This  number  however  in- 
creases in  the  segments  situated  more  anteriorly,  amounting  to  108 
in  segment  X  and  to  140  in  segment  VIII;  this  is  a  curious  excep- 
tion of  the  general  rule ,  that  the  number  of  setae  decreases  anterior- 
ly, as  is  the  case  in  most  species  of  Perichaeta.  Also  upon  the  cli- 
tellum setae  were  invariably  present,  and  not  only  confined  to  its  ven- 
tral portion,  as  stated  by  Beddard,  but  continuous  all  round  the 
body.  Between  the  papillae  of  the  male  pores  25  à  26  setae  are  to 
be  found. 
The  internal  structure,  though  agreeing  in  its  main  characters  with 
that  of  P.  indica ,  shows  also  some  differences.  The  fifth,  sixth,  seventh 
and  ninth  septum  are  more  thickened  as  they  are  in  P.  indica;  also 
the  spermathecae  have  another  appearance  as  in  the  lastnamed  species. 
They  consist  (Pl.  Ill,  fig.  30)  of  a  main  pouch  and  a  tubular  diverticu- 
lum, of  about  the  same  length;  sometimes  this  diverticulum  is  a  little 
constricted  in  its  middle  and  its  distal  half  somewhat  dilated. 
At  the  same  station  a  number  of  Perichaetidae  were  found,  which 
are  not  in  a  state  of  sexual  maturity  and  could  therefore  not  be 
identified. 
12.  Perichaeta  capensis  Horst  1). 
(—  operculata  Rosa). 
Java:  Buitenzorg,  where  the  species  seems  to  be  common,  more 
than  fifty  specimens;  Tjibodas,  six  specimens. 
The  largest  of  the  examples  measures  about  130  mm.,  the  number 
of  its  segments  amounts  to  110.  Cephalic  lobe  rather  broad,  ex- 
tending nearly  till  the  middle  of  the  buccal  segment,  where  a  faint 
groove  is  visible.  The  buccal  segment  is  not  very  distinctly  separated 
from  the  succeeding  one,  as  pointed  out  by  Rosa;  the  intersegmen- 
tal groove  however  really  exists.  The  male  generative  pores  (pl.  Ill, 
fig.  26)  upon  segment  XVIII,  are  situated  on  a  papilla,  and  show  in 
many  examples  the  appearance  of  somewhat  obliquely  directed  fissures. 
1)  Notes  Leydon  Museum,  Vol.  V,  1883,  p.  195. 
