﻿290 
  EEPOKT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  

  

  attacked, 
  as 
  after 
  they 
  become 
  about 
  2 
  inches 
  long 
  the 
  shell 
  is 
  stout 
  

   enough 
  to 
  resist 
  this 
  foe. 
  The 
  loss 
  sustained 
  from 
  this 
  source 
  is 
  very 
  

   great, 
  as 
  the 
  drills 
  are 
  often 
  present 
  in 
  large 
  numbers 
  and 
  continue 
  

   their 
  work 
  throughout 
  the 
  year. 
  

  

  The 
  two 
  large 
  conch-like 
  gasteropods 
  of 
  the 
  Atlantic 
  coast, 
  Sycoty- 
  

   pus 
  canaUculatus 
  and 
  FuUjur 
  carica 
  (plate 
  xv, 
  fig. 
  4), 
  also 
  feed 
  upon 
  the 
  

   oyster, 
  from 
  their 
  size 
  being 
  capable 
  of 
  attacking 
  the 
  largest 
  individ- 
  

   uals. 
  These 
  periwinkles, 
  ^'winkles," 
  or 
  conchs, 
  as 
  they 
  are 
  variouvsly 
  

   called, 
  appear 
  to 
  do 
  comparatively 
  little 
  damage, 
  as 
  they 
  are 
  not 
  pres- 
  

   ent 
  in 
  sufficiently 
  large 
  numbers 
  anywhere 
  esce])t 
  perhaps 
  on 
  the 
  coast 
  

   of 
  Florida. 
  

  

  Other 
  gasteropods 
  doubtless 
  feed 
  upon 
  tlie 
  oyster, 
  but 
  not 
  to 
  an 
  

   extent 
  worthy 
  of 
  consideration. 
  

  

  Upon 
  brackish- 
  water 
  beds 
  the 
  starfish 
  (plate 
  xvi) 
  is 
  not 
  usually 
  

   troublesome, 
  and 
  in 
  Chesapeake 
  Bay 
  it 
  is 
  practically 
  unknown, 
  but 
  in 
  

   Long 
  Island 
  Sound, 
  and 
  especially 
  upon 
  the 
  offshore 
  beds 
  in 
  the 
  more 
  

   saline 
  waters, 
  it 
  is 
  the 
  most 
  destructive 
  enemy 
  with 
  which 
  oystermen 
  

   have 
  to 
  contend. 
  It 
  is 
  there 
  extremely 
  abundant 
  at 
  times, 
  but 
  it 
  is 
  a 
  

   migratory 
  form, 
  and 
  sometimes 
  certain 
  beds 
  are 
  unmolested 
  while 
  others 
  

   nearby 
  are 
  almost 
  ruined 
  by 
  its 
  inroads. 
  The 
  aj)pearance 
  of 
  this 
  pest 
  

   upon 
  the 
  beds 
  is 
  without 
  warning, 
  and 
  frequently 
  the 
  ground 
  is 
  almost 
  

   devastated 
  before 
  the 
  owner 
  is 
  aware 
  of 
  their 
  presence. 
  Vast 
  swarms 
  

   or 
  schools 
  sweep 
  across 
  the 
  beds, 
  devouring 
  the 
  oysters 
  in 
  their 
  path. 
  

   The 
  migration 
  is 
  said 
  to 
  take 
  place 
  in 
  the 
  form 
  of 
  a 
  "winrow," 
  moving 
  

   in 
  some 
  cases 
  at 
  the 
  rate 
  of 
  about 
  500 
  feet 
  per 
  day. 
  Apparently 
  the 
  

   only 
  way 
  to 
  stop 
  the 
  inarch 
  of 
  these 
  hordes 
  is 
  to 
  catch 
  them 
  up 
  by 
  some 
  

   of 
  the 
  methods 
  indicated 
  in 
  pp. 
  313-310. 
  By 
  energetic 
  work 
  the 
  damage 
  

   may 
  often 
  be 
  confined 
  to 
  the 
  beds 
  at 
  the 
  edge 
  of 
  a 
  cultivated 
  area. 
  

  

  The 
  starfish 
  begins 
  its 
  destructive 
  work 
  soon 
  after 
  it 
  abandons 
  its 
  

   free-swimming 
  larval 
  condition, 
  at 
  a 
  time 
  when 
  it 
  is 
  hardly 
  larger 
  than 
  

   a 
  pin's 
  head, 
  and 
  continues 
  it 
  through 
  life. 
  At 
  first 
  it 
  feeds 
  upon 
  the 
  

   tiny 
  spai, 
  but 
  as 
  it 
  grows 
  it 
  increases 
  the 
  size 
  of 
  its 
  prey, 
  though 
  even 
  

   the 
  full-grown 
  stars 
  rarely 
  feed 
  upon 
  oysters 
  over 
  two, 
  or, 
  at 
  most, 
  

   three 
  years 
  old. 
  Small 
  oysters 
  are 
  often 
  taken 
  bodily 
  into 
  the 
  stomach 
  

   of 
  the 
  starfish, 
  a 
  proceeding 
  which 
  is 
  of 
  course 
  impossible 
  with 
  large 
  

   ones 
  or 
  those 
  firmly 
  attached 
  to 
  large 
  cultch. 
  It 
  is 
  not 
  definitely 
  known 
  

   how 
  the 
  oysters 
  are 
  opened, 
  but 
  Dr. 
  Paulus 
  Schiemenz 
  has 
  pretty 
  con- 
  

   clusively 
  demonstrated 
  the 
  probability 
  that 
  they 
  are 
  actually 
  pulled 
  

   open 
  by 
  muscular 
  effort 
  on 
  the 
  part 
  of 
  the 
  starfish. 
  

  

  If 
  the 
  co»mmOin 
  starfish 
  be 
  examined 
  there 
  will 
  be 
  found 
  on 
  the 
  under 
  

   surfiice 
  of 
  each 
  arm 
  four 
  rows 
  of 
  closely 
  c-rowded 
  suckers 
  or 
  feet 
  extend- 
  

   ing 
  from 
  the 
  mouth 
  to 
  the 
  tips 
  of 
  the 
  arms. 
  These 
  feet 
  are 
  tubular 
  

   and 
  are 
  extended 
  by 
  having 
  a 
  fluid 
  pumped 
  into 
  their 
  cavities 
  by 
  a 
  

   special 
  apparatus 
  in 
  the 
  body 
  of 
  the 
  starfish. 
  The 
  suckers 
  at 
  the 
  ends 
  

   may 
  be 
  caused 
  to 
  adhere 
  to 
  foreign 
  bodies 
  with 
  great 
  tenacity, 
  and 
  if 
  

   the 
  hydrostatic 
  pressure 
  be 
  then 
  relieved 
  and 
  the 
  muscles 
  of 
  the 
  stalks 
  

   of 
  the 
  feet 
  contract, 
  a 
  strong 
  pull 
  may 
  be 
  exerted 
  by 
  each 
  foot, 
  either 
  

  

  