﻿MUSSEL 
  EESOURCES 
  OF 
  THE 
  ILLINOIS 
  RIVER. 
  39 
  

  

  as 
  illustrated 
  in 
  his 
  paper 
  on 
  Mollusca, 
  in 
  tlie 
  Indiana 
  Geological 
  

   Report, 
  for 
  1899. 
  

  

  This 
  species 
  was 
  found 
  gravid, 
  early 
  embryo, 
  all 
  four 
  gills, 
  July 
  12. 
  

  

  4. 
  Quadrula 
  pyramidata 
  (Lea). 
  — 
  Rare; 
  a 
  few 
  samples 
  were 
  found 
  

   in 
  the 
  last 
  stretch 
  of 
  the 
  river 
  at 
  Hardin 
  and 
  at 
  Twelvemile 
  Island. 
  

   This 
  shell 
  is 
  very 
  heavy 
  anteriorly 
  and 
  thin 
  at 
  the 
  tips. 
  Some 
  

   examples 
  have 
  pink 
  nacre. 
  Tliis 
  and 
  the 
  two 
  species 
  following 
  are 
  

   usually 
  classed 
  with 
  and 
  generally 
  called 
  "pig- 
  toes" 
  by 
  the 
  mussel 
  

   fishermen. 
  

  

  5. 
  Quadrula 
  plena 
  (Lea). 
  — 
  Rare; 
  an 
  example 
  or 
  two 
  were 
  found 
  

   at 
  Peoria 
  and 
  Hardin. 
  

  

  6. 
  Quadrula 
  solida 
  (Lea). 
  — 
  A 
  comparatively 
  rare 
  species, 
  although 
  

   found 
  in 
  several 
  mussel 
  beds 
  from 
  Peoria 
  to 
  Hardin, 
  more 
  particularly 
  

   at 
  Peoria, 
  Beardstown, 
  Meredosia, 
  and 
  Valley 
  City. 
  The 
  nacre 
  varies 
  

   from 
  white 
  to 
  salmon. 
  This 
  shell 
  furnishes 
  good 
  button 
  material. 
  

  

  7. 
  Thin 
  Niggerhead, 
  Quadrula 
  coccinea 
  (Conrad). 
  — 
  This 
  is 
  a 
  very 
  

   rare 
  species 
  in 
  the 
  Illinois. 
  Some 
  examples 
  were 
  found 
  in 
  Peoria 
  Lake. 
  

  

  8. 
  Ohio 
  River. 
  Pig-toe, 
  Quadrula 
  obliqua 
  (Lamarck). 
  — 
  This 
  shell, 
  

   while 
  not 
  a 
  common 
  one 
  in 
  the 
  Illinois, 
  is 
  found 
  generally 
  distributed 
  

   throughout 
  the 
  river. 
  It 
  furnishes 
  good 
  button 
  material, 
  bat 
  is 
  

   hardly 
  equal 
  in 
  size 
  or 
  quality 
  to 
  the 
  species 
  in 
  the 
  Ohio 
  River 
  beds. 
  

  

  9. 
  Pig-toe, 
  Quadrula 
  undata"' 
  (Barnes). 
  — 
  Although 
  this 
  species 
  

   in 
  the 
  Illinois 
  is 
  the 
  most 
  abundant 
  of 
  the 
  "pig-toe" 
  group, 
  it 
  forms 
  

   but 
  a 
  small 
  percentage 
  of 
  the 
  mussel 
  output. 
  Some 
  beds, 
  depending 
  

   upon 
  the 
  parts 
  worked, 
  gave 
  the 
  following 
  percentages: 
  Chillicothe, 
  7; 
  

   Pekin, 
  3; 
  Florence, 
  9; 
  and 
  Hardin, 
  2. 
  

  

  This 
  is 
  a 
  good 
  button 
  shell, 
  but 
  has 
  considerable 
  waste 
  on 
  account 
  

   of 
  the 
  heavy 
  umbones. 
  At 
  Peoria 
  small 
  undatas 
  just 
  large 
  enough 
  to 
  

   make 
  one 
  blank 
  were 
  taken 
  and 
  sold 
  by 
  some 
  of 
  the 
  mussel 
  fishermen. 
  

   As 
  an 
  excuse 
  for 
  these 
  small 
  shells 
  in 
  their 
  piles 
  they 
  said, 
  "The 
  pig- 
  

   toes 
  are 
  running 
  smaller 
  now." 
  

  

  Some 
  examples 
  had 
  orange 
  flesh. 
  Found 
  gravid 
  in 
  all 
  four 
  gills 
  

   June 
  20. 
  

  

  10. 
  Wabash 
  Pig-toe, 
  Quculrula 
  ruhiginosa 
  (Lea.). 
  — 
  This 
  is 
  a 
  rare 
  

   species 
  in 
  the 
  Illinois. 
  The 
  only 
  examples 
  found 
  were 
  taken 
  from 
  

   Peoria 
  Lake. 
  

  

  11. 
  Two-HORNED 
  PocKETBOOK, 
  Quadrula 
  pustulata 
  (Lea). 
  — 
  

   Although 
  this 
  mussel 
  is 
  generally 
  distributed 
  throughout 
  the 
  river, 
  

   it 
  is 
  found 
  in 
  very 
  small 
  numbers. 
  It 
  is 
  usually 
  classed 
  with 
  the 
  

   pustulosa, 
  or 
  warty-backs, 
  but 
  is 
  hardly 
  as 
  good 
  material 
  for 
  manu- 
  

   facturing 
  purposes. 
  

  

  a 
  According 
  to 
  Mr. 
  Bryant 
  Walker, 
  Nautilus, 
  vol. 
  xxiv, 
  p. 
  6, 
  the 
  name 
  undata 
  has 
  precedence 
  over 
  

   the 
  one 
  (trigona, 
  Lea) 
  commonly 
  used. 
  

  

  