﻿42 
  OYSTER 
  BOTTOMS 
  OF 
  LAVACA 
  BAY, 
  TEX. 
  

  

  little 
  boring 
  clam, 
  Martesia, 
  which 
  burrows 
  its 
  oval 
  chamber 
  in 
  the 
  

   shells, 
  arc 
  all 
  more 
  or 
  less 
  nuisances, 
  and 
  therefore 
  objectionable, 
  

   but 
  they 
  do 
  comparatively 
  little 
  harm 
  in 
  Lavaca 
  Bay. 
  

  

  SPAWNING. 
  

  

  The 
  conditions 
  of 
  spawning 
  probably 
  do 
  not 
  differ 
  from 
  those 
  

   generally 
  obtaining 
  on 
  the 
  Gulf 
  coast, 
  and 
  it 
  ig, 
  therefore, 
  not 
  nec- 
  

   essary 
  to 
  discuss 
  the 
  sul)ject 
  at 
  any 
  length. 
  It 
  will 
  sufhce 
  to 
  repeat 
  

   what 
  has 
  been 
  said 
  in 
  a 
  previous 
  report.'^ 
  

  

  The 
  spawning 
  of 
  oysters 
  consists, 
  in 
  brief, 
  of 
  the 
  discharge 
  of 
  eggs 
  

   from 
  the 
  female 
  and 
  spermatozoa 
  fi-om 
  the 
  male 
  to 
  meet 
  and 
  fuse 
  in 
  

   the 
  surrounding 
  water. 
  The 
  fertilized 
  eggs 
  develop 
  into 
  minute 
  

   embryos, 
  each 
  furnished 
  with 
  a 
  little 
  brush 
  of 
  ciha 
  or 
  hairlike 
  pro- 
  

   cesses 
  which 
  vibrate 
  in 
  rhythm 
  and 
  propel 
  it 
  feebly 
  through 
  the 
  water. 
  

   Aftor 
  a 
  time 
  varying 
  with 
  the 
  temperature 
  of 
  the 
  water 
  the 
  embryos 
  

   develop 
  a 
  tiny 
  shell, 
  which 
  by 
  its 
  weight 
  eventually 
  precipitates 
  

   them 
  to 
  the 
  bottom, 
  where, 
  it 
  they 
  fall 
  upon 
  a 
  suitable, 
  clean, 
  firm, 
  

   support, 
  they 
  attach 
  and 
  grow 
  into 
  spat, 
  but 
  if 
  not 
  they 
  speedily 
  die. 
  

   As 
  their 
  own 
  powers 
  of 
  locomotion 
  are 
  inconsiderable, 
  the 
  wide 
  dis- 
  

   tribution 
  of 
  the 
  young 
  oysters 
  in 
  their 
  swimming 
  stage 
  is 
  dependent 
  

   upon 
  the 
  currents. 
  

  

  Oysters 
  in 
  the 
  spawning 
  condition 
  are 
  of 
  a 
  peculiar 
  creamy 
  color, 
  

   with 
  branching 
  lines 
  traced 
  over 
  the 
  surfaces 
  of 
  the 
  bodv. 
  When 
  

   they 
  are 
  cut 
  the 
  ripe 
  genital 
  products 
  at 
  once 
  exude 
  from 
  the 
  wound, 
  

   but 
  if 
  the 
  shell 
  be 
  opened 
  carefully 
  and 
  a 
  gentle 
  pressure 
  exerted 
  

   upon 
  the 
  body 
  they 
  will 
  be 
  discharged 
  from 
  a 
  definite 
  opening 
  Ij'ing 
  

   below 
  tlie 
  muscle 
  (usually 
  called 
  by 
  the 
  oj^stermen 
  the 
  "eye" 
  or 
  

   ''heart") 
  which 
  extends 
  between 
  the 
  two 
  valves. 
  This 
  is 
  the 
  pore 
  

   from 
  which 
  they 
  flow 
  in 
  the 
  normal 
  process. 
  Ripe 
  oysters 
  in 
  the 
  

   language 
  of 
  the 
  oystermen 
  are 
  aptly 
  described 
  as 
  ''milky." 
  

  

  Spawning 
  takes 
  place, 
  in 
  the 
  main, 
  during 
  spring 
  and 
  summer, 
  in 
  

   any 
  given 
  region 
  extending 
  over 
  a 
  period 
  of 
  some 
  months, 
  depending 
  

   upon 
  the 
  latitude 
  and 
  the 
  chmate. 
  On 
  the 
  Gulf 
  coast 
  I 
  have 
  found 
  

   (hning 
  almost 
  every 
  month 
  oysters 
  which 
  were 
  apparently 
  ]"ipe, 
  and 
  

   from 
  which 
  there 
  were 
  obtained 
  eggs 
  which 
  readily 
  separated 
  in 
  the 
  

   water 
  and 
  had 
  every 
  appearance 
  of 
  maturity. 
  Whether 
  such 
  eggs 
  

   would 
  be 
  extruded 
  during 
  the 
  winter 
  under 
  natural 
  conditions 
  is 
  

   doubtful, 
  and 
  if 
  they 
  were 
  it 
  is 
  practical 
  certain 
  that 
  they 
  would 
  

   not 
  develop, 
  as 
  the 
  experience 
  of 
  all 
  investigators 
  has 
  shown 
  that 
  

   development 
  is 
  inhibited 
  if 
  the 
  temperature 
  of 
  the 
  water 
  drops 
  

   materially 
  below 
  70°. 
  

  

  In 
  Lavaca 
  Bay 
  the 
  critical 
  temperature 
  is 
  not 
  permanently 
  passed 
  

   until 
  about 
  May, 
  and 
  the 
  major 
  part 
  of 
  the 
  spawning 
  undoubtedly 
  

   takes 
  place 
  between 
  May 
  1 
  and 
  October 
  1. 
  

  

  o 
  Oyster 
  bottoms 
  in 
  Matagorda 
  Bay. 
  By 
  II. 
  F. 
  Mooro. 
  Bureau 
  of 
  Fisheries 
  Document 
  no. 
  610. 
  1905. 
  

  

  