﻿PROPAGATION 
  OF 
  FRESH-WATER 
  MUSSELS. 
  33 
  

  

  The 
  possibility 
  of 
  implantation 
  upon 
  both 
  g-iUs 
  and 
  fins 
  of 
  the 
  host 
  

   seems 
  to 
  be 
  more 
  liable 
  to 
  occur 
  in 
  this 
  species 
  than 
  in 
  any 
  other 
  of 
  

   which 
  I 
  know 
  having 
  bookless 
  glochidia. 
  This 
  liabit 
  might 
  naturally 
  

   be 
  correlated 
  \\'it]i 
  tlie 
  large 
  size, 
  which 
  would 
  enable 
  the 
  glochidium 
  

   to 
  become 
  attached 
  more 
  readily 
  to 
  the 
  exterior 
  of 
  a 
  fis]i, 
  wjiere 
  places 
  

   for 
  attachment 
  are 
  coarser 
  than 
  on 
  tlie 
  gills. 
  This 
  character 
  should 
  

   be 
  of 
  advantage 
  in 
  artificial 
  infection, 
  through 
  more 
  diffuse 
  distri- 
  

   bution 
  on 
  the 
  fish 
  and 
  on 
  less 
  vital 
  parts, 
  permitthig 
  a 
  higher 
  optimum 
  

   infection. 
  In 
  tlie 
  present 
  experiments 
  the 
  largest 
  number 
  of 
  glo- 
  

   chidia 
  carried 
  through 
  four 
  months 
  was 
  28;** 
  this, 
  however, 
  should 
  not 
  

   be 
  considered 
  any 
  criterion 
  of 
  possibilities, 
  since 
  the 
  parasitic 
  period 
  

   in 
  this 
  case 
  is 
  probably 
  an 
  iniusually 
  long 
  one. 
  In 
  general 
  for 
  the 
  

   long-period 
  breeders 
  it 
  is 
  probably 
  more 
  economical, 
  other 
  things 
  

   being 
  equal, 
  to 
  infect 
  in 
  the 
  spring, 
  thus 
  securing 
  a 
  shorter 
  and 
  more 
  

   certain 
  development. 
  

  

  The 
  infection 
  of 
  the 
  fins 
  in 
  the 
  catfish 
  caUs 
  attention 
  to 
  a 
  difference 
  

   in 
  suitability 
  to 
  infection 
  between 
  such 
  a 
  fleshy 
  fin 
  and 
  the 
  mem- 
  

   braneous 
  type 
  of 
  the 
  Centrarchidse, 
  whicli 
  group 
  lias 
  been 
  found 
  so 
  

   favorable 
  for 
  gill 
  infections. 
  

  

  Tlie 
  encystment 
  of 
  the 
  glocjiidia 
  of 
  Q. 
  heros 
  (see 
  pi. 
  iv, 
  fig. 
  266) 
  

   indicates 
  a 
  less 
  vigorous 
  reaction 
  of 
  the 
  hosts 
  tissues 
  than, 
  for 
  

   example, 
  in 
  the 
  niggerhead 
  ; 
  in 
  that 
  the 
  cysts 
  are 
  comparatively 
  thin. 
  

  

  Propagation. 
  — 
  The 
  very 
  large 
  size 
  of 
  Q. 
  heros 
  and 
  the 
  thickness 
  of 
  

   the 
  shell 
  give 
  possibilities 
  of 
  use 
  which 
  are 
  found 
  in 
  no 
  otiier 
  mussel. 
  

   At 
  tlie 
  present 
  time 
  it 
  is, 
  according 
  to 
  manufacturers, 
  with 
  the 
  

   mucket, 
  L. 
  ligamentina, 
  and 
  the 
  three-ridge, 
  Q. 
  plicata, 
  one 
  of 
  the 
  

   three 
  chief 
  shells 
  used 
  in 
  the 
  button 
  industry, 
  possibly 
  taking 
  first 
  

   place 
  for 
  large 
  buttons; 
  in 
  quality 
  it 
  is 
  considered 
  second 
  grade, 
  but 
  

   varies 
  with 
  locahty. 
  From 
  the 
  results 
  of 
  this 
  investigation 
  it 
  is 
  

   sliown 
  to 
  be 
  one 
  of 
  the 
  most 
  favorable 
  among 
  the 
  Quadrulas 
  for 
  arti- 
  

   ficial 
  propagation. 
  The 
  reasons 
  for 
  this 
  are 
  as 
  follows: 
  It 
  is 
  a 
  fall 
  or 
  

   winter 
  breeder, 
  thus 
  not 
  being 
  hmited 
  to 
  a 
  brief 
  summer 
  breeding 
  

   period 
  at 
  a 
  season 
  when 
  it 
  is 
  more 
  difficult 
  to 
  deal 
  witli 
  live 
  fish 
  and 
  

   at 
  a 
  time 
  wlien 
  the 
  otlier 
  Quadrulas 
  are 
  breeding. 
  It 
  has 
  at 
  least 
  

   three 
  host 
  fish 
  and 
  probably 
  more 
  upon 
  whicli 
  it 
  can 
  be 
  propagated. 
  

   The 
  tremendous 
  number 
  of 
  glochidia 
  produced 
  and 
  their 
  great 
  

   vitality 
  are 
  features 
  that 
  increase 
  the 
  chances 
  of 
  success 
  in 
  artificial 
  

   propagation. 
  Its 
  natural 
  habitat 
  is 
  more 
  easily 
  imitated 
  under 
  

   artificial 
  conditions 
  than 
  that 
  of 
  species 
  which 
  are 
  restricted 
  to 
  river 
  

   channels 
  in 
  that 
  it 
  is 
  found 
  in 
  the 
  more 
  quiet 
  waters 
  of 
  lagoons 
  and 
  

   lakes 
  as 
  well 
  as 
  in 
  the 
  open 
  rivers. 
  For 
  a 
  heavy 
  shell 
  it 
  is 
  a 
  rapidly 
  

   growing 
  species. 
  

  

  o 
  Through 
  the 
  winter 
  of 
  1913-14 
  Q. 
  heros 
  was 
  carried 
  to 
  maturity 
  tn 
  large 
  numbers 
  (800 
  to 
  1,200 
  per 
  flsh) 
  

   on 
  the 
  gills 
  of 
  the 
  following: 
  Pomoxis 
  annularis, 
  P. 
  sparoides, 
  Lepomis 
  pallidus, 
  Apomotis 
  cyanellus 
  and 
  

   Am,eiurus 
  Sp., 
  and 
  in 
  smaller 
  numbers 
  on 
  the 
  lins 
  of 
  the 
  following: 
  A. 
  grunniens, 
  Ictalurus 
  punctatus. 
  

   Ameiurus 
  Sp. 
  

  

  22889°— 
  14 
  28 
  

  

  