﻿LOBSTER 
  ATTD 
  CLAM 
  ITTVESTIGATIONS. 
  199 
  

  

  It 
  is 
  true, 
  however, 
  that 
  up 
  to 
  a 
  certain 
  limit, 
  the 
  number 
  of 
  clams 
  

   which 
  ma}^ 
  exist 
  on 
  any 
  area 
  depends 
  on 
  the 
  amount 
  of 
  food 
  which 
  

   they 
  are 
  able 
  to 
  obtain. 
  Mobius 
  has 
  said 
  concerning- 
  the 
  food 
  of 
  the 
  

   oyster, 
  "The 
  quantity 
  of 
  nourishment 
  varies 
  in 
  proportion 
  to 
  the 
  

   amount 
  of 
  water 
  which 
  passes 
  over 
  the 
  beds." 
  We 
  will 
  find 
  that 
  

   rapidity 
  of 
  current 
  seems 
  actually 
  to 
  have 
  much 
  to 
  do 
  with 
  the 
  num- 
  

   ber 
  of 
  clams 
  which 
  ma}" 
  exist 
  on 
  a 
  given 
  area. 
  Besides 
  this, 
  evidence 
  

   will 
  be 
  given 
  to 
  show 
  that 
  the 
  increase 
  in 
  size 
  of 
  individuals 
  depends 
  

   upon 
  the 
  amount 
  of 
  food, 
  that 
  growth 
  is 
  much 
  accelerated, 
  and 
  sexual 
  

   maturity 
  perhaps 
  earlier 
  attained 
  where 
  currents 
  are 
  swift. 
  This 
  of 
  

   course 
  is 
  onl}^ 
  possible 
  where 
  other 
  conditions, 
  such 
  as 
  the 
  character 
  

   of 
  the 
  bottom, 
  are 
  favorable. 
  

  

  In 
  connection 
  with 
  the 
  question 
  of 
  food 
  and 
  growth 
  on 
  natural 
  beds, 
  

   a 
  word 
  may 
  be 
  said 
  concerning 
  the 
  existence 
  of 
  the 
  soft 
  clam 
  below 
  

   the 
  low-water 
  mark. 
  The 
  clam 
  is 
  almost 
  always 
  dug 
  from 
  beds 
  that 
  

   are 
  exposed 
  at 
  low 
  tide. 
  Twice 
  a 
  day 
  there 
  is 
  a 
  period, 
  of 
  some 
  con- 
  

   siderable 
  duration 
  in 
  some 
  localities, 
  in 
  which 
  the 
  creature 
  is 
  unable 
  to 
  

   obtain 
  food. 
  It 
  would 
  seem 
  that 
  individuals 
  below 
  the 
  low-water 
  line, 
  

   which 
  are 
  continualh^ 
  immersed, 
  might 
  thus 
  have 
  an 
  advantage 
  which 
  

   should 
  result 
  in 
  their 
  more 
  rapid 
  growth. 
  It 
  is 
  stated 
  by 
  Dean, 
  in 
  his 
  

   study 
  of 
  the 
  oyster 
  in 
  the 
  South 
  Carolina 
  sounds, 
  that 
  " 
  the 
  best 
  feeding 
  

   conditions 
  are 
  during 
  the 
  rising 
  of 
  the 
  tide, 
  which 
  appears 
  to 
  carry 
  

   shoreward 
  from 
  the 
  deeper 
  water 
  a 
  number 
  of 
  pelagic 
  forms. 
  High 
  

   tide 
  contains 
  the 
  next 
  highest 
  percentage 
  of 
  oyster 
  food. 
  The 
  poorest 
  

   feeding 
  conditions 
  are 
  shown 
  at 
  low 
  water." 
  But 
  some 
  feeding 
  by 
  

   submerged 
  clams 
  along 
  the 
  shore 
  would 
  be 
  possible 
  at 
  low 
  tide, 
  and 
  

   Mead 
  gives 
  experimental 
  evidence 
  to 
  show 
  that 
  clams 
  continually 
  sub- 
  

   merged 
  actually 
  do 
  grow 
  faster 
  than 
  those 
  which 
  are 
  exposed 
  at 
  

   low 
  tide. 
  

  

  In 
  spite 
  of 
  the 
  fact 
  that 
  food 
  conditions 
  are 
  apparently 
  favorable 
  

   below 
  the 
  low-water 
  mark, 
  it 
  seems 
  doubtful 
  whether 
  submerged 
  beds 
  

   are 
  relatively 
  numerous. 
  That 
  there 
  are 
  many 
  such 
  beds 
  along 
  our 
  

   coasts 
  there 
  is 
  no 
  question. 
  They 
  are 
  present 
  in 
  the 
  Essex 
  River, 
  in 
  

   salt 
  ponds 
  east 
  of 
  Woods 
  Hole, 
  at 
  West 
  Falmouth, 
  and 
  one 
  or 
  two 
  

   adjacent 
  points 
  on 
  the 
  shore 
  of 
  Buzzards 
  Bay. 
  Mead 
  speaks 
  of 
  clams 
  

   appearing 
  in 
  the 
  market 
  in 
  Februar^^, 
  1900, 
  which 
  had 
  been 
  dug 
  below 
  

   low 
  water 
  in 
  the 
  Kickemuit 
  River 
  and 
  at 
  Wickford 
  on 
  Narragansett 
  

   Bay. 
  There 
  are 
  also 
  beds 
  at 
  Suit 
  Pond, 
  Point 
  Judith, 
  and 
  a 
  large 
  bed 
  

   is 
  known 
  near 
  Sag 
  Harbor, 
  Long 
  Island. 
  There 
  are, 
  no 
  doubt, 
  many 
  

   more 
  of 
  these; 
  but 
  all 
  these 
  compared 
  with 
  beach 
  beds 
  may 
  not 
  be 
  nearly 
  

   so 
  great 
  in 
  extent. 
  This 
  is 
  a 
  conjecture, 
  and 
  entertained 
  only 
  because, 
  

   at 
  man}" 
  points, 
  beaches 
  have 
  been 
  examined 
  and 
  dug 
  below 
  the 
  ordinary 
  

   low-tide 
  mark, 
  at 
  the 
  full-moon 
  tides, 
  and 
  apparently 
  very 
  few 
  clams 
  

   were 
  present. 
  It 
  appears 
  from 
  a 
  somewhat 
  superficial 
  examination, 
  

   that 
  clams 
  on 
  the 
  ordinary 
  clam 
  l)each 
  extend 
  down 
  from 
  the 
  usual 
  

  

  