﻿6 
  PEOPAGATTON 
  OF 
  FRESH-WATER 
  MUSSELS. 
  

  

  of 
  the 
  Lampsilis 
  group, 
  chiefly 
  Lampsilis 
  Ugamentina 
  and 
  L. 
  ano- 
  

   dontoides. 
  With 
  one 
  possible 
  exception, 
  none 
  of 
  the 
  Quadrula 
  group 
  

   of 
  mussels, 
  including 
  some 
  of 
  the 
  most 
  valuable 
  commercial 
  shells, 
  

   had 
  been, 
  up 
  to 
  the 
  time 
  of 
  the 
  present 
  investigation, 
  carried 
  through 
  

   the 
  parasitic 
  stage, 
  though 
  many 
  experiments 
  had 
  been 
  made 
  on 
  

   various 
  species 
  of 
  fish 
  and 
  under 
  varied 
  conditions 
  to 
  determine 
  a 
  

   suitable 
  method 
  of 
  propagation. 
  The 
  rarity 
  of 
  successful 
  infections, 
  

   along 
  with 
  other 
  indications, 
  suggests 
  that, 
  as 
  in 
  other 
  cases 
  of 
  para- 
  

   sitism 
  in 
  the 
  animal 
  and 
  vegetable 
  kingdom, 
  each 
  mussel 
  may 
  have 
  

   its 
  appropriate 
  host 
  or 
  hosts 
  restricted 
  to 
  a 
  species 
  of 
  fish, 
  a 
  genus 
  or 
  

   a 
  family, 
  as 
  the 
  case 
  might 
  be, 
  and 
  that 
  the 
  reason 
  for 
  failure 
  was 
  

   due 
  to 
  not 
  finding 
  the 
  proper 
  host. 
  

  

  Since 
  the 
  number 
  of 
  species 
  of 
  mussel 
  for 
  this 
  locality 
  (Fairport, 
  

   Iowa) 
  is 
  4O 
  or 
  more 
  and 
  the 
  number 
  of 
  species 
  of 
  fairly 
  common 
  fish 
  

   at 
  least 
  60, 
  the 
  problem 
  of 
  determining 
  the 
  appropriate 
  host 
  for 
  each 
  

   mussel 
  is 
  obviously 
  quite 
  complex. 
  To 
  determine 
  the 
  hosts 
  for 
  each 
  

   species 
  of 
  mussel 
  by 
  artificial 
  infection, 
  a 
  "trial 
  and 
  error" 
  method 
  

   would 
  be 
  roundabout 
  and 
  difficult. 
  Obviously 
  a 
  more 
  direct 
  solution 
  

   of 
  the 
  problem, 
  as 
  I 
  have 
  shown 
  in 
  a 
  previous 
  paper 
  (Howard, 
  1912), 
  

   would 
  be 
  secured 
  by 
  a 
  study 
  of 
  natural 
  infections, 
  i. 
  e., 
  fish 
  taken 
  at 
  

   large 
  are 
  examined 
  for 
  glochidia 
  and 
  when 
  present 
  these 
  are 
  deter- 
  

   mined 
  as 
  to 
  species, 
  condition, 
  etc. 
  In 
  the 
  present 
  investigation 
  of 
  

   some 
  of 
  the 
  Quadrula 
  group 
  of 
  mussels 
  the 
  above 
  method 
  was 
  the 
  

   one 
  chiefly 
  employed. 
  Studies 
  were 
  begun 
  in 
  February, 
  1912, 
  upon 
  

   assignment 
  of 
  the 
  problem 
  by 
  the 
  director. 
  Dr. 
  R. 
  E. 
  Coker, 
  at 
  the 
  

   Government 
  biological 
  laboratory 
  at 
  Fairport, 
  Iowa." 
  

  

  METHODS 
  AND 
  TECHNIQUE 
  OF 
  EXPERIMENTS. 
  

  

  As 
  stated 
  above, 
  the 
  matter 
  of 
  first 
  importance 
  in 
  determining 
  

   how 
  to 
  propagate 
  a 
  given 
  species 
  of 
  mussel 
  seemed 
  to 
  be 
  the 
  finding 
  

   of 
  a 
  suitable 
  host. 
  In 
  making 
  this 
  search 
  I 
  have 
  examined 
  as 
  many 
  

   local 
  species 
  of 
  fish 
  as 
  were 
  obtainable, 
  identifying, 
  if 
  possible, 
  all 
  

   glochidia 
  found 
  upon 
  the 
  gills 
  or 
  fins. 
  Some 
  glochidia, 
  because 
  of 
  

   peculiarities 
  of 
  form 
  or 
  size, 
  were 
  readily 
  determined, 
  while 
  others 
  

   were 
  less 
  easily 
  identified 
  because 
  of 
  fewer 
  apparent 
  differences. 
  In 
  

   this 
  study 
  I 
  have 
  made 
  identifications 
  by 
  comparison 
  of 
  the 
  glo- 
  

   chidium 
  found 
  in 
  the 
  natural 
  infections 
  with 
  a 
  series 
  of 
  preparations 
  

   and 
  drawings 
  of 
  glochidia 
  (see 
  Surber, 
  1912) 
  obtained 
  from 
  gravid 
  

   mussels. 
  

  

  Fishes 
  were 
  examined 
  for 
  natural 
  infections 
  wherever 
  obtainable, 
  

   but 
  attention 
  was 
  also 
  given 
  to 
  securing 
  them 
  in 
  the 
  vicinity 
  of 
  

   special 
  mussel 
  beds. 
  Infected 
  filaments 
  of 
  gills 
  or 
  portions 
  of 
  fins 
  

   have 
  been 
  examined 
  and 
  drawn, 
  first 
  in 
  the 
  fresh 
  state 
  and 
  then 
  fixed 
  

  

  « 
  Special 
  acknowledgment 
  is 
  due 
  Prof. 
  Lefevre 
  and 
  Prof. 
  Curtis, 
  of 
  the 
  University 
  of 
  Missouri, 
  (or 
  data 
  

   cf 
  their 
  experiments 
  placed 
  at 
  our 
  disposal. 
  

  

  