﻿MUSSEL 
  RESOURCES 
  OF 
  THE 
  ILLINOIS 
  RIVER. 
  41 
  

  

  In 
  some 
  localities, 
  as 
  at 
  Quiver 
  Lake, 
  above 
  Havana, 
  the 
  old 
  heros 
  

   are 
  dead; 
  not 
  a 
  single 
  living 
  example 
  was 
  taken, 
  excepting 
  the 
  young, 
  

   indicating 
  that 
  whatever 
  the 
  cause 
  of 
  the 
  mortality 
  had 
  been, 
  more 
  

   favorable 
  conditions 
  exist 
  at 
  present. 
  

  

  Small 
  shells 
  2 
  or 
  3 
  inches 
  long 
  are 
  taken 
  by 
  the 
  mussel 
  fishermen; 
  

   and 
  while 
  they 
  make 
  a 
  few 
  good 
  blanks, 
  to 
  take 
  them 
  is 
  very 
  waste- 
  

   ful, 
  as 
  they 
  should 
  be 
  thrown 
  back 
  into 
  the 
  river 
  and 
  allowed 
  to 
  

   mature. 
  

  

  In 
  our 
  collection 
  there 
  are 
  three 
  examples 
  of 
  this 
  shell, 
  which 
  

   show 
  very 
  clearly 
  the 
  abnormal 
  ridge 
  and 
  valley 
  caused 
  by 
  the 
  growth 
  

   of 
  pearls 
  witliin. 
  Two 
  of 
  the 
  shells 
  were 
  found 
  near 
  Bath, 
  111., 
  and 
  

   the 
  other 
  at 
  Peoria. 
  

  

  Plate 
  II 
  represents 
  a 
  heros 
  or 
  washboard, 
  measuring 
  4f 
  by 
  6| 
  

   inches. 
  The 
  nacre 
  is 
  remarkably 
  clear. 
  From 
  the 
  entire 
  shell, 
  5 
  

   dozen 
  24-Hne 
  blanks 
  were 
  cut 
  at 
  the 
  button 
  factory 
  of 
  Mr. 
  J. 
  H, 
  

   Garner, 
  Beardstown, 
  111. 
  

  

  17. 
  Blue-point, 
  Quadrula 
  undulata 
  (Barnes). 
  — 
  The 
  undulata 
  is 
  a 
  

   very 
  abundant 
  species 
  and 
  is 
  regarded 
  by 
  the 
  button 
  men 
  as 
  a 
  very 
  

   desirable 
  shell. 
  It 
  is 
  rather 
  flattish, 
  particularly 
  at 
  ChiUicothe, 
  

   though 
  lower 
  down 
  the 
  river 
  it 
  is 
  somewhat 
  more 
  inflated. 
  It 
  is 
  

   rather 
  thin 
  and 
  light 
  in 
  weight 
  but 
  of 
  good 
  size 
  and 
  luster. 
  

  

  The 
  sheU 
  is 
  commonly 
  called 
  the 
  blue-point, 
  but 
  in 
  some 
  camps 
  the 
  

   name 
  of 
  "purple- 
  tip" 
  is 
  applied 
  to 
  it 
  on 
  account 
  of 
  the 
  sUght 
  purple 
  

   tinge 
  at 
  the 
  posterior 
  end. 
  

  

  A 
  few 
  examples 
  almost 
  free 
  from 
  ridges 
  were 
  found 
  in 
  Peoria 
  

   Lake 
  and 
  at 
  Florence, 
  111. 
  Prof. 
  Richardson, 
  of 
  the 
  State 
  biological 
  

   station 
  at 
  Havana, 
  had 
  two 
  similar 
  specimens 
  taken 
  from 
  the 
  river 
  

   at 
  that 
  place. 
  

  

  This 
  mussel 
  was 
  found 
  spawnmg 
  July 
  12. 
  

  

  18. 
  Three-ridge, 
  Quadrula 
  plicata 
  (Say). 
  — 
  The 
  three-ridge 
  is 
  

   much 
  less 
  abundant 
  and 
  not 
  so 
  valuable 
  a 
  shell 
  as 
  the 
  blue-pomt. 
  

   Being 
  usually 
  more 
  mflated, 
  heavier 
  at 
  the 
  beaks, 
  and 
  with 
  larger 
  

   ridges, 
  it 
  leaves 
  more 
  waste 
  after 
  the 
  blanks 
  are 
  cut. 
  

  

  At 
  Meredosia, 
  it 
  is 
  claimed 
  that 
  the 
  plicata 
  has 
  a 
  tendency 
  to 
  

   crumble 
  when 
  cut. 
  Found 
  gravid 
  July 
  8 
  and 
  15. 
  

  

  19. 
  Bui.LHEAD, 
  Pleurobema 
  sesopus 
  (Green). 
  — 
  Rare; 
  examples 
  were 
  

   found 
  only 
  at 
  Bath 
  and 
  Meredosia. 
  It 
  is 
  brittle 
  and 
  not 
  a 
  good 
  

   l)utton 
  shell; 
  moreover, 
  being 
  so 
  uncommon 
  in 
  the 
  Illinois, 
  it 
  is 
  dis- 
  

   regarded 
  altogether. 
  

  

  20. 
  Elephant-ear, 
  TJnio 
  crassidens 
  (Lea). 
  — 
  Rare; 
  although 
  found 
  

   m 
  most 
  of 
  the 
  beds, 
  the 
  percentage 
  is 
  so 
  small 
  that 
  it 
  is 
  practically 
  a 
  

   negligible 
  quantity. 
  The 
  nacre 
  varies 
  from 
  pink 
  to 
  white. 
  This 
  

   shell 
  is 
  used 
  for 
  makmg 
  novelties. 
  

  

  21. 
  Lady-finger, 
  Spike, 
  TJnio 
  gihbosus 
  (Barnes). 
  — 
  The 
  lady-finger 
  

   is 
  not 
  now 
  a 
  commercial 
  shell 
  unless 
  it 
  be 
  white, 
  which 
  is 
  seldom 
  the 
  

  

  