﻿284 
  REPOET 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  

  

  have 
  sometimes 
  been 
  found 
  in 
  the 
  stomachs 
  of 
  the 
  oysters, 
  but 
  so 
  

   sparingly 
  that 
  they 
  formed 
  no 
  appreciable 
  part 
  of 
  the 
  food. 
  

  

  It 
  is 
  the 
  opinion 
  of 
  the 
  oj^stermen 
  that 
  much 
  of 
  the 
  food 
  of 
  the 
  

   oyster 
  comes 
  from 
  fresh- 
  water 
  sources, 
  and 
  they 
  thus 
  account 
  for 
  the 
  

   fact 
  that 
  oysters 
  thrive 
  best 
  in 
  brackish 
  water. 
  This 
  also 
  I 
  have 
  been 
  

   unable 
  to 
  substantiate, 
  having 
  found, 
  on 
  the 
  contrarj^, 
  that 
  the 
  plant 
  

   forms 
  which 
  compose 
  the 
  oyster's 
  food 
  are 
  produced 
  on 
  the 
  bottom 
  of 
  

   the 
  rivers 
  and 
  bays 
  in 
  which 
  the 
  03"ster 
  beds 
  are 
  located, 
  in 
  the 
  brack- 
  

   ish 
  water 
  over 
  the 
  beds, 
  or 
  in 
  the 
  salt 
  water 
  carried 
  over 
  the 
  beds 
  by 
  

   the 
  tide. 
  Plants 
  similar 
  to 
  those 
  utilized 
  by 
  the 
  oysters 
  but 
  not 
  iden- 
  

   tical 
  species 
  were 
  found 
  in 
  the 
  ooze 
  at 
  the 
  surface 
  of 
  the 
  bottom 
  

   of 
  fresh-water 
  streams, 
  ponds, 
  and 
  marshes 
  in 
  the 
  region 
  of 
  the 
  

   oyster 
  beds. 
  

  

  The 
  plant 
  forms 
  that 
  furnish 
  the 
  oyster 
  food 
  in 
  North 
  and 
  Newport 
  

   rivers 
  are 
  the 
  same, 
  though 
  not 
  equall}' 
  abundant 
  in 
  the 
  two 
  streams. 
  

   As 
  many 
  as 
  30 
  species 
  of 
  diatoms 
  were 
  found, 
  from 
  first 
  to 
  last, 
  in 
  the 
  

   stomachs 
  of 
  the 
  oysters, 
  but 
  nine-tenths 
  of 
  the 
  bulk 
  of 
  the 
  contents 
  

   was 
  made 
  up 
  of 
  individuals 
  of 
  four 
  species, 
  figures 
  for 
  which 
  are 
  

   given 
  on 
  page 
  286. 
  These 
  species 
  are, 
  in 
  the 
  order 
  of 
  their 
  abundance, 
  

   Melosira 
  scidpta, 
  Pleurosigma 
  sjxncerii, 
  Eupodiscusr 
  adlatus^ 
  and 
  

   Naviciila 
  diclyma. 
  

  

  Melosira 
  sculpta 
  is 
  a 
  species 
  of 
  diatom 
  the 
  individuals 
  of 
  which 
  

   adhere 
  end 
  to 
  end, 
  thus 
  forming 
  filaments, 
  which 
  are 
  quite 
  brittle, 
  

   however, 
  and 
  seldom 
  contain 
  more 
  than 
  ten 
  individuals, 
  the 
  usual 
  

   number 
  being 
  five 
  or 
  six. 
  The 
  individuals 
  are 
  disk 
  shaped 
  and 
  have 
  

   beautifully 
  sculptured 
  walls 
  (fig. 
  9). 
  The 
  filaments 
  have 
  no 
  motion 
  

   of 
  their 
  own, 
  and 
  are 
  hence 
  found 
  chiefly 
  on 
  or 
  close 
  to 
  the 
  

   bottom, 
  except 
  on 
  windy 
  days 
  when 
  the 
  water 
  is 
  considerably 
  roiled. 
  

   The 
  species 
  is 
  equally 
  abundant 
  in 
  the 
  rivers, 
  harbor, 
  and 
  the 
  open 
  

   sea, 
  and 
  forms 
  a 
  considerable 
  part 
  of 
  the 
  diet 
  of 
  oysters 
  everywhere 
  

   in 
  the 
  Beaufort 
  region. 
  It 
  was 
  not 
  found 
  in 
  any 
  locality 
  in 
  Pamlico 
  

   Sourid, 
  except 
  near 
  Ocracoke 
  Inlet, 
  which 
  fact, 
  taken 
  with 
  the 
  above, 
  

   indicates 
  that 
  it 
  is 
  a 
  marine 
  form. 
  

  

  Eivpodiscus 
  radiatus 
  (fig. 
  6), 
  is 
  the 
  largest 
  diatom 
  found 
  in 
  Beaufort 
  

   waters. 
  The 
  individual 
  plants 
  are 
  disk-shaped 
  and 
  nonmotile, 
  but, 
  

   unlike 
  those 
  of 
  the 
  preceding 
  species, 
  are 
  always 
  found 
  singly 
  and 
  

   usually 
  above 
  the 
  bottom. 
  Owing 
  to 
  this 
  position 
  above 
  the 
  bottom, 
  

   the 
  reef 
  oysters 
  usually 
  contain 
  a 
  larger 
  proportion 
  of 
  these 
  plants 
  

   in 
  their 
  stomachs 
  than 
  the 
  oysters 
  on 
  the 
  beds 
  in 
  deeper 
  waters, 
  

   and 
  from 
  the 
  fact 
  that 
  the 
  diatom 
  is 
  more 
  common 
  in 
  salt 
  than 
  

   in 
  brackish 
  v;ater, 
  the 
  oysters 
  on 
  the 
  beds 
  near 
  the 
  mouths 
  of 
  the 
  

   rivers 
  and 
  in 
  the 
  harbor 
  get 
  a 
  more 
  plentiful 
  suppl}^ 
  than 
  those 
  farther 
  

   up 
  the 
  rivers. 
  The 
  species 
  was 
  found 
  in 
  Pamlico 
  Sound 
  near 
  Ocracoke 
  

   Inlet, 
  but 
  "ot 
  over 
  the 
  beds 
  in 
  Swan 
  Quarter 
  and 
  Wyesocking 
  bays. 
  

   Although 
  the 
  num1)er 
  of 
  individuals 
  found 
  in 
  the 
  oysters' 
  stomachs 
  

  

  