59 
each  other  in  their  external  appearance,  show  so  marked  differences 
in  their  internal  structure,  that  some  of  them ,  without  any  doubt  must, 
be  regarded  as  the  types  of  new  genera.  Rosa  already  proposed  to 
separate  Megascolex  from  Perichaeta,  and  Beddard  in  a  recent  paper 
added  the  new  genera  Diporochaeta ,  Anisochaeta  and  Hoplochaeta. 
Though  his  modification  must  be  looked  on  as  a  great  improvement , 
I  believe  nevertheless,  that  it  must  be  considered  as  only  a  provisional 
attempt  to  divide  this  family,  for  unfortunately  the  information  on 
the  structure  of  several  species  is  very  superficial  and  incomplete.  The 
genus  Perionyx,  though  presenting  large  paired  nephridia ,  in  my 
opinion,  must  not  be  separated  from  the  Perichaetidae,  as  proposed 
by  Benham;  perhaps  Megascolex  armatus,  which  possesses  tufts  of 
nephridial  tubules  as  well  as  large  nephridia,  will  prove  to  form  a  link 
between  the  genera  plectonephrica  and  meganephrica. 
Perichaeta  Schmarda  (s.  s.) 
(Megascolex  Baird,  Horst). 
Setae  numerous,  arranged  in  a  continuous  row  round  each  segment. 
Clitellum  consisting  of  three  segments  XIV -XVI.  Gizzard  posterior 
to  segment  VII.  Intestinal  coeca  in  segment  XXVI  *)• 
The  confusion  of  Megascolex  and  Perichaeta ,  caused  by  Schmarda's 
and  Vaillant's  misunderstanding  of  Templeton's  original  description, 
and  by  Baird's  inaccurate  observations,  was  cleared  up  by  Beddard, 
who  had  the  opportunity  of  examining  Templeton's  type-specimens. 
9.  Perichaeta  musica  Horst 2). 
Java:  Tjibodas. 
Of  this  huge  worm,  the  largest  known  Perichaeta-s^ecies ,  several 
examples  were  collected  at  Tjibodas. 
The  largest  specimen  measures  440  mm.  in  length;  the  number 
of  its  segments  amount  to  124.  In  the  description  of  this  worm,  in 
my  earlier  paper,  I  omitted  to  note,  that  the  row  of  setae  is  not  en- 
tirely continuous ,  but  that  there  is  a  small  gap  in  the  dorsal  mid-line , 
equal  to  the  interspaces  between  2  or  3  of  the  neighbouring  setae; 
1)  According  to  Beddaud's  recent  investigations  (Proc.  Zool.  Soc.  1892)  in  P.  tapro- 
banae  the  intestinal  coeca  should  be  absent. 
2)  Notes  Leyden  Museum,  Yol.  V,  1883,  p.  193;  Ibidem,  Vol.  XII,  1890,  p.  236 
Pl.  X,  fig.  6;  A.  G.  Vorderman,  Natuurk.  Tijdschr.  Ned.  Indië,  Vol.  XLI,  1881,  p.  1 
PI.  l,i  Ibidem,  Vol.  XLIV,  1884,  p.  1. 
