54 
the  buccal  cavity  (pharynx?),  which  also  becomes  visible  in  other  Lum- 
bricidae.  Beddard  l)  and  Benham  8)  too  take  to  the  view,  that  „the 
prostomium  is  absent  and  that  the  mouth  opens  terminally." 
I  cannot  quite  agree  with  this  opinion.  Although  in  the  most  of  our 
specimens  the  cephalic  extremity  is  inverted  —  the  first  segment  with 
bristles  thus  lying  foremost  —  such  is  not  the  case  with  all  of  them. 
The  examination  of  a  longitudinal  section  of  such  a  specimen  (Pl.  Til, 
fig.  33)  proves,  that  a  lobe  of  the  buccal  segment  extends  dorsally 
beyond  the  mouth.  Such  a  lobe  was  also  observed  in  an  other  indi- 
vidual, (Pl.  IV,  fig.  85)  and  shows  at  its  ventral  side  a  pair  of  longitu- 
dinal grooves,  which  diverge  towards  the  anterior  extremity.  In 
transverse  sections  too  these  grooves  were  visible;  they  show  no 
particular  structure,  but  their  epithelial  layer  is  not  so  high  as  in 
the  surrounding. 
I  believe ,  that  the  figure  of  a  longitudinal  section  of  the  anterior 
end  of  P.  corethrurus  (Quart.  Journ.  Micr.  Sc«  Vol.  XXIX,  Pl.  XXIII, 
fig.  1)  published  by  Beddard,  is  too  diagrammatical,  and  does  not 
represent  a  sagittal  but  a  tangential  section.  Moreover  another  mistake 
has  been  made  into  this  figure,  as  already  indicated  by  Rosa ,  viz.  that 
the  pore  of  the  mucous  gland  is  figured  in  the  third  segment ,  furnished 
with  bristles,  instead  of  in  the  first.  As  the  tubes  of  these  mucous 
glands  in  their  structure  much  resemble  those  of  the  nephridia,  and 
moreover  the  latter  organs  are  absent  in  segment  II  en  III,  Perrier 
already  made  the  suggestion,  that  the  mucous  gland  would  represent  a 
highly  developed  nephridium;  Beddard  now  believes  to  have  demon- 
strated the  perfect  homology  of  both  organs,  by  finding  out  the  internal 
funnels  of  the  mucous  gland.  For  he  observed  „three  or  four  funnels 
of  considerable  size  and  of  a  somewhat  horse-shoeshaped  form;  two 
of  them  were  situated  at  the  distal  extremity  of  the  gland  in  the 
sixth  (fourth?  Bedd.)  segment,  the  third  more  anterior  in  position, 
corresponding  to  the  fifth."  I  quite  agree  with  Rosa,  that  the 
exactness  of  this  observation  is  not  without  doubt,  for  Beddard  says  : 
„the  mucous  glands  occupy  the  first  six  segments ,  which  contain  no 
nephridia  of  the  normal  type  ;  these  latter  do  not  commence  until  after." 
This  must  be  a  slip  of  the  pen,  for  as  visible  in  fig.  34 ,  nephridia  are 
1)  Quartl.  Journ.  Micr.  Sc.  vol.  XXKI,  1890,  p.  159;  Proc.  R.  Phys.  Soc.  Edinburgh, 
1891,  p.  235. 
2)  Quartl.  Journ.  Microsc.  Sc.  XXXI,  p.  250. 
