51 
being  found  in  Brasil,  British  Guyana,  Jamaica,  Martinique,  Maur- 
itius, Singapore,  Java,  Sumatra,  Nias,  Celebes  (Weber)  and  Queensland. 
8.  Pontoscolex  corethrurus  F.  Müller. 
Java:  Buitenzorg,  very  common. 
Sumatra:   Padang,  Singkarah,   Manindjau,   Pajakombo,  Kaju- 
tanam,  a  great  number  of  young  specimens,  under  dead  wood. 
Celebes:  near  Makassar,  several  specimens  in  freshwater. 
In  a  critical  paper  on  the  systematical  characters  of  P.  corethrurus 
Rosa  *)  has  tried  to  demonstrate ,  that  all  the  specimens  of  the  above- 
named  different  countries  probably  belong  to  the  same  species,  and 
that  the  differences  in  characters,  mentioned  for  some  of  them,  have 
no  value,  because  they  are  based  upon  a  different  manner  of  enume- 
ration of  the  segments.  With  regard  to  77.  dubia  from  Sumatra 2) , 
described  by  my-self,  I  am  quite  prepared  to  agree  with  Dr.  Rosa's 
opinion;  the  specimens  at  my  disposal  were  in  a  very  poor  state  of 
preservation  and  therefore  the  buccal- segment  seems  to  have  been  over- 
looked. As  to  the  specimens  examined  by  Perrier,  which  came  from 
different  regions  (Java,  Martinique,  Brasil)  there  still  rests  with  me 
some  doubt,  whether  they  all  are  referable  to  one  and  the  same  species. 
In  all  our  specimens  (a  rather  large  number)  the  setae  of  the  ven- 
tral couples  commence  to  diverge  in  segment  XI  (Xth  setigerous), 
the  external  of  them  (2)  moving  dorsally;  the  setae  of  the  dorsal 
couples  usually  diverge  in  segment  XII,  in  some  individuals  how- 
ever upon  segment  XI  or  XIII,  the  divergence  being  not  always 
symmetrical.  Behind  the  clitellum  the  setae  begin  to  alternate  in 
position,  the  dorsal  ones  first,  those  of  the  ventral  couples  upon  seg- 
ment XXVIII  or  XXIX.  The  internal  setae  of  the  ventral  couples  (1), 
in  the  succeeding  segments  of  a  great  portion  of  the  body,  remain 
situated  in  the  same  line. 
In  the  specimens ,  examined  by  Perrier  3),  the  superior  setae 
of  the  dorsal  couples  commence,  according  to  his  description,  to  be 
displaced  on  segment  XIII  (XIV  Perrier)  and  the  external  ventral 
ones  not  before  segment  XXIII  (XXIV  Perrier);  he  also  found copu- 
1)  Ann.  del  Mus.  Civico  di  Storia  Natur,  di  Genova,  Vol.  XXVII,  1889,  p.  1 
2)  Midden-Sumatra,  Reizen  en  onderzoekingen  der  Sumatra-Expeditie ,  IV,  Zoologie, 
XII,  Vermes,  p.  7. 
3)  Archives  de  Zoologie  Expérimentale,  Vol.  XIII,  1874,  p.  394. 
