﻿>OTES 
  ON 
  S03IE 
  OF 
  THE 
  EARLY 
  STAGES 
  OF 
  DEVEL- 
  

   OPMENT 
  OF 
  THE 
  (LAM 
  OR 
  MANANOSE 
  (Mya 
  

   arenaria.) 
  

  

  The 
  spawning 
  period 
  of 
  this 
  moUusk 
  lasts 
  from 
  the 
  

   10th 
  of 
  September 
  to 
  about 
  the 
  middle 
  of 
  October, 
  or 
  for 
  

   about 
  forty 
  days. 
  The 
  sex 
  of 
  the 
  adults, 
  in 
  a 
  spawning 
  

   condition, 
  may 
  be 
  very 
  easily 
  learned. 
  Open 
  the 
  shell 
  

   of 
  the 
  animal 
  carefully, 
  remove 
  a 
  small 
  portion 
  of 
  the 
  

   richly 
  colored 
  yellow 
  body 
  mass 
  with 
  a 
  knife, 
  scissors 
  or 
  

   forceps. 
  These 
  fragments, 
  squeezed 
  or 
  "teased 
  out" 
  in 
  

   a 
  watch-glass 
  with 
  a 
  few 
  drops 
  of 
  sea-water, 
  allow 
  a 
  

   milky 
  fluid 
  to 
  escape. 
  Under 
  a 
  magnifying 
  power 
  of 
  

   four 
  or 
  five 
  times, 
  the 
  eggs 
  of 
  the 
  female 
  are 
  visible 
  in 
  

   this 
  milky 
  fluid 
  as 
  very 
  minute 
  white 
  points 
  of 
  nearl 
  y 
  

   uniform 
  size. 
  The 
  male 
  cells 
  are 
  too 
  small 
  to 
  be 
  seen 
  

   with 
  the 
  aid 
  of 
  so 
  Ioav 
  a 
  magnifying 
  power, 
  and 
  the 
  fluid 
  

   retains 
  its 
  milky 
  apqearance 
  just 
  as 
  it 
  does 
  to 
  the 
  naked 
  

   eye. 
  It 
  is 
  only 
  under 
  high 
  powers, 
  as 
  much 
  as 
  250 
  dia- 
  

   meters, 
  with 
  the 
  compound 
  microscope, 
  that 
  the 
  sper- 
  

   matozoa 
  or 
  male 
  cells 
  may 
  be 
  made 
  visible, 
  as 
  minute 
  

   oval 
  bodies 
  with 
  a 
  long, 
  lash-like 
  tail 
  in 
  rapid 
  motion. 
  

   These 
  differences 
  enable 
  the 
  operator 
  to 
  distinguish 
  the 
  

   sexes, 
  after 
  a 
  little 
  experience 
  ; 
  indeed, 
  it 
  is 
  possible 
  

   with 
  training, 
  to 
  note 
  the 
  differences 
  between 
  the 
  male 
  

   fluid 
  and 
  the 
  eggs 
  of 
  the 
  female 
  when 
  removed 
  from 
  the 
  

   animals, 
  with 
  the 
  naked 
  eye. 
  

  

  Artificial 
  impregnation 
  of 
  the 
  eggs 
  was 
  effected 
  in 
  the 
  

   same 
  way 
  as 
  in 
  the 
  case 
  of 
  the 
  oyster 
  ; 
  that 
  is, 
  portions 
  

   of 
  the 
  rix:>e 
  ovary 
  of 
  the 
  female 
  are 
  removed 
  and 
  chopped 
  

   up 
  in 
  a 
  watch-glass 
  or 
  small 
  saucer 
  with 
  sea- 
  water, 
  taking 
  

   care 
  to 
  remove 
  all 
  the 
  large 
  fragments 
  of 
  ovarian 
  tissue 
  

   by 
  straining 
  the 
  milky 
  substance 
  through 
  bolting 
  cloth, 
  

  

  