﻿10 
  PROPAGATION 
  OF 
  FKESH-WATER 
  MUSSELS. 
  

  

  found 
  on 
  catfishes. 
  Previous 
  to 
  that 
  time 
  all 
  examinations 
  of 
  cat- 
  

   fishes 
  had 
  favored 
  the 
  belief 
  that 
  they 
  were 
  immune 
  to 
  all 
  glochidial 
  

   infection. 
  Other 
  records 
  for 
  this 
  fish 
  were 
  obtained 
  through 
  «Tidy 
  

   and 
  August, 
  the 
  breeding 
  period 
  for 
  the 
  mussel. 
  The 
  fish 
  were 
  taken 
  

   by 
  seining 
  over 
  known 
  shell 
  beds 
  in 
  one 
  instance, 
  in 
  others 
  in 
  wing 
  

   nets 
  and 
  bait 
  nets 
  of 
  commercial 
  fishermen. 
  In 
  all, 
  during 
  1912, 
  17 
  

   records 
  of 
  infection 
  were 
  obtained 
  out 
  of 
  39 
  fish 
  examined, 
  and 
  9 
  of 
  

   these 
  were 
  determined 
  as 
  Q. 
  pustulosa. 
  

  

  This 
  glochidium 
  is 
  more 
  readily 
  identified 
  in 
  infections 
  than 
  some 
  

   others, 
  because 
  of 
  its 
  large 
  size 
  and 
  owing 
  to 
  its 
  peculiar 
  shape. 
  None 
  

   of 
  the 
  mussels 
  of 
  similar 
  dimensions 
  have 
  the 
  same 
  form. 
  The 
  nearest 
  

   approach 
  to 
  it 
  is 
  Lampsilis 
  luteola. 
  (See 
  description 
  of 
  glochidium 
  

   above.) 
  The 
  glochidia 
  in 
  infection 
  were 
  usually 
  well 
  encysted, 
  and 
  

   in 
  many 
  cases 
  development 
  was 
  far 
  advanced, 
  even 
  to 
  the 
  extent 
  of 
  

   some 
  growth 
  beyond 
  the 
  glochidial 
  shell. 
  (PI. 
  iii, 
  fig. 
  19, 
  23.) 
  

   This 
  development 
  of 
  an 
  extra 
  embryonic 
  shell 
  in 
  the 
  parasitic 
  

   stage 
  has 
  been 
  reported 
  (Coker 
  and 
  Surber, 
  1911) 
  for 
  the 
  Proptera 
  

   (Ortmann, 
  1912) 
  group, 
  but 
  not, 
  I 
  believe, 
  among 
  the 
  Quadrulas. 
  

   One 
  record 
  only 
  was 
  obtained 
  of 
  Q. 
  pustulosa 
  on 
  another 
  fish, 
  the 
  

   yellow 
  cat, 
  Leptops 
  olivaris, 
  hat 
  this 
  was 
  important, 
  as 
  it 
  suggested 
  a 
  

   possible 
  host 
  for 
  this 
  mussel, 
  and 
  led 
  to 
  the 
  discovery 
  of 
  many 
  infec- 
  

   tions 
  in 
  Ictalurus 
  punctatus, 
  although 
  one 
  had 
  been 
  seen 
  in 
  that 
  

   species 
  before. 
  In 
  9 
  other 
  specimens 
  of 
  L. 
  olivaris 
  examined 
  by 
  me 
  

   and 
  44 
  by 
  Mr. 
  T. 
  Surber 
  in 
  August, 
  no 
  infections 
  were 
  found. 
  From 
  

   the 
  standpoint 
  of 
  natural 
  infections, 
  7. 
  punctatus 
  is 
  indicated 
  as 
  the 
  

   natural 
  host 
  for 
  Q. 
  pustulosa, 
  with 
  a 
  possible 
  extension 
  to 
  other 
  

   species 
  of 
  the 
  Silurida^. 
  After 
  August 
  28 
  and 
  durmg 
  the 
  autumn 
  no 
  

   natural 
  infections 
  were 
  obtained 
  from 
  a 
  total 
  of 
  98 
  fish 
  examined. 
  

   This 
  date 
  corresponds 
  with 
  the 
  latest 
  date 
  for 
  gravid 
  mussels 
  of 
  the 
  

   species. 
  On 
  August 
  23, 
  2 
  gravid 
  shells 
  were 
  secured 
  from 
  a 
  total 
  of 
  

   48. 
  After 
  this 
  date 
  none 
  were 
  found 
  in 
  a 
  total 
  of 
  176 
  examined. 
  This 
  

   gives 
  a 
  space 
  of 
  five 
  days 
  after 
  the 
  last 
  gravid 
  mussels 
  were 
  foimd, 
  

   during 
  which 
  the 
  natural 
  infections 
  were 
  obtained 
  The 
  indications 
  

   from 
  this 
  are 
  that 
  the 
  parasitic 
  period 
  is 
  brief. 
  If 
  the 
  parasitic 
  

   period 
  were 
  a 
  long 
  one, 
  say 
  a 
  month, 
  this 
  correspondence 
  of 
  dates 
  

   woidd 
  be 
  lacking. 
  

  

  The 
  character 
  of 
  the 
  cysts 
  and 
  their 
  position 
  on 
  the 
  gill 
  filament 
  

   are 
  features 
  to 
  which 
  attention 
  has 
  been 
  called 
  as 
  of 
  importance, 
  per- 
  

   haps, 
  in 
  determining 
  the 
  possibilities 
  of 
  artificial 
  infection. 
  The 
  

   cysts 
  of 
  Q. 
  pustulosa 
  on 
  Ictalurus 
  punctatus 
  are 
  of 
  ordinary 
  size. 
  They 
  

   are 
  often 
  set 
  off 
  by 
  a 
  slight 
  furrow 
  or 
  indentation 
  (see 
  pi. 
  iii, 
  fig. 
  23), 
  

   which 
  is 
  quite 
  characteristic. 
  The 
  position 
  is 
  chiefly 
  on 
  the 
  edge 
  of 
  

   the 
  filaments, 
  often 
  near 
  the 
  base, 
  a 
  rather 
  imusual 
  location. 
  Lefevre 
  

   and 
  Curtis 
  (1912) 
  are 
  of 
  the 
  opinion 
  that 
  those 
  fish 
  in 
  which 
  the 
  

   glochidia 
  are 
  distributed 
  on 
  the 
  tips 
  of 
  the 
  filament 
  are 
  able 
  to 
  carry 
  

  

  