﻿42 
  MUSSEL 
  RESOURCES 
  OF 
  THE 
  ILLINOIS 
  RIVER. 
  

  

  case. 
  It 
  is 
  found 
  in 
  large 
  quantities 
  along 
  tlie 
  river, 
  some 
  beds, 
  

   which 
  the 
  clammers 
  avoid 
  as 
  much 
  as 
  possible, 
  having 
  a 
  very 
  large 
  

   percentage. 
  Above 
  the 
  upper 
  bridge 
  at 
  Peoria 
  there 
  are 
  two 
  small 
  

   beds 
  of 
  this 
  species; 
  one 
  bed 
  consists 
  mostly 
  of 
  white 
  nacred 
  shells, 
  

   while 
  in 
  the 
  other 
  the 
  nacre 
  is 
  the 
  ordinary 
  dull 
  purple 
  color. 
  At 
  

   Meredosia 
  a 
  driveway 
  leading 
  from 
  the 
  river 
  to 
  the 
  bank 
  above 
  is 
  

   covered 
  with 
  about 
  60 
  tons 
  of 
  these 
  shells. 
  They 
  had 
  been 
  pur- 
  

   chased 
  at 
  a 
  low 
  price 
  in 
  the 
  hope 
  that 
  there 
  would 
  be 
  a 
  demand 
  for 
  

   them. 
  Button 
  cutters 
  claim 
  that 
  even 
  the 
  white 
  gihhosus 
  do 
  not 
  

   make 
  good 
  blanks 
  on 
  account 
  of 
  the 
  shell 
  being 
  brittle. 
  

  

  In 
  the 
  Cumberland 
  River, 
  crassidens 
  is 
  much 
  more 
  al)undant 
  than 
  

   gihhosus, 
  w^hich 
  is 
  the 
  poposite 
  condition 
  in 
  the 
  Illinois. 
  

  

  22. 
  Spectacle-case, 
  Margaritana 
  monodonta 
  (Say). 
  — 
  Rare; 
  only 
  

   one 
  example 
  was 
  found 
  during 
  the 
  entire 
  trip, 
  at 
  Diamond 
  Island, 
  

   above 
  Hardin, 
  although 
  there 
  were 
  some 
  specimens 
  from 
  this 
  river 
  

   at 
  the 
  biological 
  laboratory 
  at 
  Havana, 
  111. 
  The 
  shell 
  is 
  too 
  thin 
  

   and 
  brittle 
  to 
  be 
  of 
  any 
  commercial 
  importance. 
  Not 
  so 
  large 
  as 
  the 
  

   Cumberland 
  River 
  species. 
  

  

  23. 
  White 
  heel-splitter, 
  Symphynota 
  comjjlanata 
  (Barnes). 
  — 
  

   Wlien 
  of 
  sufficient 
  thickness, 
  this 
  shell 
  is 
  used 
  for 
  buttons. 
  It 
  is 
  

   fairly 
  common 
  in 
  the 
  IlUnois, 
  and 
  from 
  its 
  flat 
  shape 
  and 
  outUne 
  is 
  

   often 
  called 
  the 
  ''elephant-ear" 
  by 
  the 
  mussel 
  fishermen. 
  It 
  is 
  found 
  

   in 
  sloughs 
  and 
  in 
  mud 
  bottoms. 
  

  

  24. 
  Fluted-shell, 
  Symphynota 
  costata 
  (Rafinesque). 
  — 
  Rare; 
  only 
  

   one 
  example 
  found, 
  at 
  Bath. 
  

  

  2.5. 
  Rock-shell, 
  Bastard, 
  Queen, 
  Arcidens 
  confragosus 
  (Say). 
  — 
  

   Found 
  in 
  small 
  quantities 
  on 
  almost 
  all 
  of 
  the 
  mussel 
  beds. 
  It 
  is 
  

   not 
  regarded 
  as 
  particularly 
  good 
  button 
  material. 
  This 
  shell 
  is 
  

   sometimes 
  called 
  the 
  black 
  pocketbook, 
  rock 
  pocketbook, 
  and 
  bas- 
  

   tard. 
  An 
  extra 
  large 
  and 
  inflated 
  example 
  was 
  found 
  at 
  Havana, 
  

   June 
  28. 
  

  

  In 
  young 
  examples 
  of 
  confragosus 
  the 
  interior 
  surface 
  of 
  the 
  shell 
  

   is 
  indented 
  or 
  pitted 
  to 
  conform 
  with 
  the 
  more 
  pronounced 
  pustules 
  

   on 
  the 
  outside. 
  This 
  condition 
  at 
  the 
  end 
  of 
  probably 
  two 
  years 
  

   disappears, 
  the 
  shell 
  becoming 
  covered 
  with 
  subsequent 
  layers 
  of 
  

   nacre. 
  

  

  26. 
  Anodonta 
  corpulenta 
  (Cooper). 
  — 
  Four 
  Anodontas, 
  the 
  corpu- 
  

   lenta, 
  grandis, 
  suhorhiculata, 
  and 
  infihecillis, 
  were 
  found 
  during 
  the 
  

   present 
  survey. 
  They 
  are 
  thin, 
  paperlikc 
  shells 
  and 
  have 
  no 
  com- 
  

   mercial 
  or 
  economic 
  value, 
  excepting 
  perhaps 
  as 
  they 
  are 
  used 
  occa- 
  

   sionally 
  by 
  the 
  mussel 
  fishermen 
  for 
  fish 
  bait 
  or 
  hog 
  feed. 
  The 
  cor- 
  

   pulenta 
  is 
  found 
  in 
  slouglis, 
  and 
  on 
  soft 
  mud 
  bottoms. 
  

  

  27. 
  Floater, 
  Anodonta 
  grandis 
  (Say). 
  — 
  Distributed 
  as 
  the 
  pre- 
  

   ceding 
  species. 
  Shells 
  which 
  have 
  recently 
  been 
  killed 
  rise 
  to 
  the 
  

   surface 
  of 
  the 
  water 
  on 
  account 
  of 
  the 
  gases 
  of 
  decomposition 
  and 
  

  

  