31 
and  Megascolex,  which  hitherto  are  only  found  in  the  Oriental 
region.  As  to  the  genus  Perionyx,  we  have  five  species  from  the 
Oriental  region,  while  only  a  single  one  is  described  by  Michaelsen 
from  Sansibar.  Cryptodrilus  insular  is  forms  a  link  between  the  fauna's 
of  the  Malay  Archipelago  and  Australia,  for  which  latter  country 
this  genus  is  characteristic.  A  remarquable  phenomenon  is  the  presence 
in  the  Malayan  region  of  the  genus  Benhamia ,  of  which  three  species 
are  described  in  the  present  paper;  they  considerably  augment  the 
number  of  species,  found  out  of  Africa,  where  this  genus  appears  to 
be  indigenous.  As  we  can  hardly  ascribe  the  presence  of  these  worms  to 
man's  interference,  Michaelsen's  assertion  „dass  die  JBenhamien  eine  sehr 
geringe  Verbreitungskraft  haben"  appears  to  be  somewhat  premature. 
ACANTHODKILIDAE. 
Though  Âcanthodrilidae  are  known  from  different  parts  of  the  world 
viz.  Afrika,  S.  America,  N.  Zealand  etc.,  no  species  are  described 
hitherto  from  the  Indo- Malayan  regions. 
The  specimens,  collected  by  Prof.  Weber,  all  are  small  worms,  which 
must  be  ranged  among  the  genus  Benhamia,  characterized  according 
to  Michaelsen's  description  ;  by  having  the  setae  placed  at  the  ventral 
side,  by  the  situation  of  the  male  pores  in  a  fossa,  by  the  presence 
(usually)  of  more  than  one  gizzard,  and  of  an  excretory  system  in 
the  forme  of  delicate  tubules  1).  I  am  not  quite  convinced ,  however, 
that  those  characters  are  sufficient  for  a  natural  subdivision  of  the 
genus  Acanthodrilus. 
I  cannot  agree  with  Michaelsen  that  Benham's  genus  Trigaster 
ought  to  be  cancelled  and  included  into  the  genus  Benhamia;  provi- 
sorily  it  appears  to  me  preferable  to  retain  both  generic  names,  for 
Tr.  Lankesteri,  as  Benham  has  recently  pointed  out 2),  is  distinguished 
from  about  all  the  Benhamia-species  not  only  by  the  great  extent  of 
its  clitellum  (XIV  to  XL),  but  also  by  the  absence  of  the  intestinal 
coeca  and  the  penial  setae. 
1)  Jahrb.  der  Hamburg.  Wissens.  Anstalten  VI,  1889,  p.  6;  VII,  1890,  p.  3. 
2)  Ann.  a.  Mag.  of  Nat.  History,  1890,  p.  414. 
