Proto3oa  parasitical  on  “Polybora  socialis” 
by 
Drs.  GOMES  DE  FARIA,  MARQUES  DA  CUNHA  and  O.  DA  FONSECA. 
(With  plate  3.) 
Various  authors  have  noticed  marine 
worms  boring  galleries  in  the  shells  cf  ma¬ 
rine  mollusks,  dead  or  alive,  and  using  them 
for  shelter.  While  studying  the  development 
of  Ostrea  parasitica  at  the  now  extinct  ma¬ 
rine  biological  station,  we  frequently  obser¬ 
ved  polychaetic  worms  in  their  shells  ;  one 
of  them,  which  was  always  found  in  holes, 
dug  in  the  under  shell,  was  determined  as 
Poiydora  socialis.  At  first  we  were  only  in¬ 
terested  in  studying  the  worm  and  only  later 
we  discovered  the  species  of  protozoa 
living  in  its  intestine,  which  form  the  object 
of  this  paper. 
The  material  for  this  investigation  was 
not  restricted,  as  oysters  with  parasites  were 
easily  obtained  from  fisheries  near  to  the 
Praia  da  Saudade  (in  the  bay)  and  also  on 
the  fishmarket  and  at  the  hotels  of  Rio  de 
Janeiro.  At  first  we  extracted  the  Poiydora 
by  mecanical  means,  opening  the  holes  ca¬ 
refully  with  a  scalpel,  but  this  process  proved 
very  laborious  and  required  the  greatest  care, 
in  order  to  prevent  the  instrument  or  pieces 
of  the  shell  from  fatally  injuring  the  very 
soft  tissues  of  the  worm.  By  numerous  trials 
we  obtained  only  one  or  two  intact  speci¬ 
mens.  Afterwards  we  were  informed  of  an 
interesting  method,  due  to  CARAZZI  (1),  who 
uses  a  1  or  2<Voo  solution  of  chloral  hydrate 
in  sea  water;  after  a  few  hours  contact  of 
this  solution  with  the  shells,  the  polychaetic 
worms  come  out  of  them,  sometimes  in  very 
great  number. 
In  the  “Brazil  — Medico”  (2)  we  gave  a 
preliminary  note  describing  shortly  two  spe¬ 
cies  of  parasitical  protozoa,  found  in  the  exa¬ 
mined  specimens  of  Poiydora.  More  recenJy 
we  also  noticed  frequently  a  gregarine  of 
the  genus  Doliocystis,  belonging  to  a  spedes 
we  could  not  determinate.  Of  this  we  only 
give  a  figure,  while  the  description  of  the 
two  other  species  forms  the  principal  part  of 
this  paper. 
1)  Mittheil.  d.  zool.  Stat.  zu  Neapel,  Vol.  11, 
2)  Brazil — Medico,  an.  31,  n.  29,  pag.  243). 
