﻿35 
  

  

  PART 
  II-EMBRYOLOGY. 
  

  

  THE 
  SEXES 
  OF 
  THE 
  OYSTER. 
  

  

  A 
  list 
  of 
  the 
  contradictory 
  opinions 
  which 
  various 
  writers 
  

   liave 
  expressed 
  regarding 
  the 
  distinctness 
  of 
  the 
  sexes 
  of 
  the 
  

   oyster 
  is 
  hardly 
  worth 
  publishing, 
  since 
  all 
  the 
  thoroughly 
  

   competent 
  observers 
  who 
  liave 
  investigated 
  the 
  subject 
  in 
  

   modern 
  times 
  agree 
  that 
  each 
  oyster 
  is, 
  at 
  the 
  breeding 
  season, 
  

   either 
  a 
  male 
  or 
  a 
  female. 
  

  

  During 
  my 
  investigations 
  I 
  submitted 
  more 
  than 
  a 
  thousand 
  

   oysters 
  to 
  microscopic 
  examination. 
  My 
  studies 
  were 
  carried 
  

   on 
  during 
  the 
  breeding 
  season, 
  and 
  I 
  did 
  not 
  find 
  a 
  single 
  

   hermaphrodite. 
  The 
  male 
  cells 
  are 
  so 
  small 
  compared 
  with 
  

   the 
  eggs 
  that 
  it 
  would 
  be 
  impossible 
  to 
  state 
  that 
  a 
  mass 
  of 
  

   eggs 
  taken 
  from 
  the 
  ovary 
  contained 
  no 
  spermatozoa, 
  although 
  

   they 
  could 
  not 
  escape 
  detection 
  if 
  they 
  were 
  at 
  all 
  abundant. 
  

  

  On 
  the 
  other 
  hand, 
  a 
  single 
  egg 
  in 
  the 
  field 
  of 
  the 
  micro- 
  

   scope 
  in 
  a 
  drop 
  of 
  male 
  tin 
  id 
  would 
  be 
  very 
  conspicuous, 
  and 
  

   -could 
  not 
  escape 
  detection 
  ; 
  and 
  the 
  fact 
  that 
  not 
  a 
  single 
  case 
  

   of 
  this 
  kind 
  occurred 
  is 
  sufficient 
  to 
  establisli 
  the 
  distinctness 
  

   of 
  the 
  sexes 
  at 
  the 
  breeding 
  season. 
  

  

  A 
  short 
  time 
  since, 
  October 
  25th, 
  I 
  examined 
  a 
  number 
  of 
  

   oysters 
  with 
  the 
  same 
  result. 
  I 
  found 
  six 
  females 
  with 
  ovaries 
  

   filled 
  with 
  nearly 
  ripe 
  ovarian 
  eggs, 
  and 
  eight 
  males 
  whose 
  

   testes 
  were 
  filled 
  with 
  spermatozoa, 
  most 
  of 
  which 
  were 
  im- 
  

   mature, 
  but 
  some 
  of 
  them 
  fully 
  developed 
  and 
  active. 
  

  

  One 
  of 
  the 
  males 
  and 
  one 
  female 
  were 
  liardened 
  in 
  chromic 
  

   acid, 
  and 
  a 
  number 
  of 
  microscopic 
  sections 
  were 
  cut 
  from 
  

   various 
  parts 
  of 
  the 
  reproductive 
  organs 
  of 
  each. 
  None 
  of 
  the 
  

   ovarian 
  follicles 
  or 
  parts 
  of 
  follicles 
  of 
  the 
  female 
  contained 
  

   anything 
  but 
  eggs, 
  and 
  not 
  a 
  single 
  egg 
  at 
  any 
  stage 
  of 
  devel- 
  

   opment 
  was 
  found 
  in 
  any 
  part 
  of 
  the 
  body 
  of 
  the 
  ma]e. 
  

  

  