41 
the  pharynx  and  the  oesophagus  is  covered  at  the  dorsal  side  by  a 
large  mass  of  glandular  cells.  The  muscular  fibres  radiating  from  the 
roof  of  the  pharynx  ;  and  connecting  this  organ  with  the  body- wall ,  per- 
forate the  septa  and  unite  with  the  longitudinal  muscular  layer  of 
the  body- wall  in  the  intersegmental  region  of  the  Vth,  YIth  and  Vllth 
segment. 
The  vascular  system  presents  the  usual  structure  and  agrees 
with  that  of  some  Acanthodrilus-species.  There  is  a  single  dorsal 
vessel  and  a  supra-neural  (ventral)  vessel,  only  the  infra-neural  vessel 
is  absent.  The  tubular  intestine,  behind  the  gizzard,  moreover  is 
furnished  with  a  supra-intestinal  vessel,  and  two  infra-intestinal  ves- 
sels, communicating  with  the  vascular  plexus  of  the  alimentary 
canal;  these  intestinal  vessels  are  connected  by  mesenteries  with,  the 
dorsal  as  well  as  with  the  ventral  trunc.  There  are  five  pairs  of 
commissural  vessels  in  segment  VIII  to  XII ,  communicating  through  a 
small  branch  with  the  dorsal  as  well  as  with  the  supra-intestinal  vessel. 
Nephridia  are  present  except  in  the  anterior  fourteen  segments; 
they  are  rather  long  and  consist  of  several  loops  of  perforated  cells. 
Genital  organs.  Two  pairs  of  testes  are  situated  at  their  usual 
place  in  segment  X  and  XI,  attached  to  the  posterior  side  of  the 
anterior  septum;  they  lie  free  in  the  body-cavity,  opposite  to  the 
funnels  of  the  sperm-ducts  and  do  not  seem  to  be  enclosed  in  the  se- 
minal vesicles.  Of  these  organs  there  are  four  pairs  in  segment  IX, 
X,  XI  and  XII;  the  first  pair  of  them  depends  on  the  anterior 
septum  of  the  segment  X,  the  second  and  third  pair  from  the  poste- 
rior septum  of  the  same  segment.  The  second  pair  of  seminal  vesicles 
arises  from  the  dorsal  half  of  the  10th  septum  and  is  directed  for- 
ward; therefore  this  pair  lies  in  the  Xth  segment.  They  are  fused 
together  on.  the  dorsal  side.  The  third  pair  of  seminal  vesicles ,  arising 
from  the  ventral  half  of  the  10th  septum,  is  directed  backward, 
and  occupies  the  Xlth  segment.  The  fourth  pair  of  them ,  arising  from 
the  posterior  side  of  the  11th  septum,  is  the  largest  and  not  only 
fills  out  the  total  cavity  of  the  XII th  segment,  but  also  pushes  far 
backward  its  posterior  septum.  In  consequence  of  the  described  situation, 
the  cells,  thrown  off  by  the  testes  in  segment  X,  can  get  in  the  first 
and  third  pair  of  the  seminal  vesicles ,  while  the  cells  arising  from  the 
testes  in  segment  XI,  can  enter  the  second  and  fourth  pair  of  them. 
We  do  not  know  the  forces  by  which  the  spermmothercells  are  di- 
