﻿210 
  

  

  and 
  better 
  able 
  to 
  resist 
  the 
  attacks 
  of 
  enemies 
  and 
  changes 
  

   of 
  environment, 
  and 
  thus 
  we 
  find 
  on 
  the 
  imworked 
  beds, 
  

   where 
  the 
  oysters 
  are 
  practically 
  in 
  a 
  natural 
  state, 
  that 
  the 
  

   decrease 
  in 
  passing 
  from 
  young 
  growth 
  to 
  mature 
  oysters 
  is 
  

   about 
  30 
  per 
  cent., 
  or 
  about 
  one-third 
  of 
  a 
  given 
  number 
  per- 
  

   ish 
  in 
  passing 
  from 
  the 
  first 
  to 
  the 
  fourth 
  year 
  of 
  their 
  exist- 
  

   ence. 
  

  

  Here 
  our 
  information 
  ceases, 
  but 
  enough 
  has 
  been 
  gathered 
  

   to 
  indicate 
  the 
  proportion 
  which 
  nature 
  has 
  assigned 
  as 
  neces- 
  

   sary 
  between 
  the 
  young 
  and 
  the 
  mature 
  oysters. 
  For 
  every 
  

   1000 
  of 
  the 
  latter 
  there 
  should 
  be 
  1500 
  of 
  the 
  former, 
  if 
  the 
  

   number 
  of 
  brood 
  oysters 
  necessary 
  to 
  maintain 
  the 
  fecundity 
  

   of 
  the 
  beds 
  is 
  to 
  be 
  kept 
  up, 
  and 
  though 
  this 
  proportion 
  is 
  

   based 
  upon 
  data 
  which 
  is 
  not 
  quite 
  sufficient, 
  yet, 
  as 
  I 
  have 
  

   said, 
  it 
  is 
  all 
  that 
  has 
  been 
  afforded 
  as 
  yet, 
  and 
  may 
  be 
  ac- 
  

   cepted 
  within 
  certain 
  limits. 
  Certainly 
  whatever 
  it 
  should 
  

   be, 
  the 
  number 
  of 
  the 
  rising 
  generation 
  of 
  the 
  animals 
  should 
  

   never 
  be 
  less 
  than 
  that 
  of 
  the 
  older, 
  or 
  there 
  should 
  ahvays 
  

   be 
  as 
  many 
  young 
  as 
  mature 
  on 
  any 
  bed. 
  

  

  A 
  greatly 
  increased 
  proportion 
  of 
  young 
  to 
  mature 
  oysters 
  

   would 
  show 
  either 
  one 
  of 
  the 
  two 
  things 
  — 
  either 
  the 
  mortality 
  

   in 
  passing 
  from 
  youth 
  to 
  maturity 
  was 
  much 
  greater 
  than 
  

   shown 
  by 
  the 
  dredging 
  results 
  in 
  the 
  Bay, 
  or 
  that 
  a 
  very 
  large 
  

   number 
  of 
  mature 
  oysters 
  had 
  been 
  removed 
  by 
  other 
  than 
  

   natural 
  causes. 
  

  

  In 
  considering 
  these 
  several 
  beds 
  the 
  question 
  of 
  food 
  and 
  

   other 
  necessary 
  supplies 
  has 
  not 
  been 
  considered, 
  as 
  it 
  is 
  evi- 
  

   dent 
  that 
  when 
  an 
  oyster 
  bed 
  is 
  formed 
  and 
  exists 
  naturally, 
  

   all 
  the 
  conditions 
  for 
  its 
  successful 
  life 
  are 
  probably 
  present, 
  

   and 
  any 
  failure 
  of 
  an 
  important 
  supply 
  would 
  be 
  followed 
  by 
  

   a 
  speedy 
  extinction 
  of 
  all 
  the 
  oysters 
  on 
  the 
  bed. 
  Such 
  deter- 
  

   minations 
  of 
  the 
  quality 
  and 
  quantity 
  of 
  the 
  food, 
  character 
  

   of 
  bottom 
  and 
  water, 
  and 
  other 
  matters, 
  are 
  only 
  of 
  interest 
  

   and 
  desirable 
  for 
  the 
  purpose 
  of 
  comparing 
  one 
  locality 
  with 
  

   another. 
  Such 
  was 
  not 
  the 
  purpose 
  of 
  this 
  investigation, 
  and 
  

   consequently 
  the 
  determination 
  of 
  those 
  points 
  has 
  been 
  but 
  

   incidental 
  to 
  the 
  work. 
  

  

  Probably 
  the 
  fecundity 
  of 
  a 
  bed 
  is 
  increased 
  to 
  a 
  certain 
  

  

  