﻿40 
  MUSSEL 
  RESOURCES 
  OF 
  THE 
  ILLINOIS 
  RIVER. 
  

  

  12. 
  Warty-back, 
  Quadrula 
  pustulosa 
  (Lea). 
  — 
  The 
  pustulosa, 
  or 
  

   warty-back, 
  is 
  a 
  very 
  common 
  shell 
  in 
  the 
  Illinois, 
  certain 
  very 
  pro- 
  

   ductive 
  beds 
  yielding 
  a 
  large 
  per 
  cent 
  of 
  the 
  output. 
  This 
  mussel, 
  

   though 
  thin 
  at 
  the 
  tips 
  and 
  in 
  old 
  specimens 
  heavy 
  at 
  the 
  beaks, 
  is 
  of 
  

   good 
  size, 
  quality, 
  and 
  luster 
  and 
  often 
  classed 
  next 
  to 
  the 
  niggerhead 
  

   for 
  manufacturing 
  purposes. 
  There 
  are 
  a 
  number 
  of 
  variable 
  forms 
  

   of 
  this 
  species 
  among 
  our 
  examples, 
  one 
  of 
  which 
  (no. 
  F 
  6245), 
  found 
  

   at 
  Henry, 
  111., 
  June 
  19, 
  was 
  referred 
  to 
  Mr. 
  Bryant 
  Walker, 
  who 
  

   states 
  that 
  it 
  ' 
  ' 
  is 
  a 
  young 
  and 
  very 
  much 
  inflated 
  dorfeuilleamus, 
  which 
  

   Simpson 
  calls 
  a 
  synonym 
  of 
  pustulosa. 
  I 
  think 
  it 
  quite 
  likely 
  that 
  

   some 
  day 
  it 
  may 
  be 
  given 
  varietal 
  rank." 
  This 
  mussel 
  often 
  contains 
  

   a 
  number 
  of 
  slugs; 
  one 
  of 
  our 
  examples 
  had 
  nearly 
  50 
  small 
  nacreous 
  

   pieces 
  at 
  the 
  dorsal 
  part 
  of 
  the 
  body. 
  Found 
  gravid 
  July 
  5. 
  

  

  13. 
  Maple-leaf, 
  Quadrula 
  fragosa 
  (Conrad). 
  — 
  Kare; 
  an 
  example 
  

   was 
  found 
  in 
  Peoria 
  Lake, 
  but 
  it 
  does 
  not 
  agree 
  exactly 
  with, 
  fragosa 
  

   as 
  we 
  found 
  it 
  in 
  the 
  Cumberland 
  River, 
  near 
  ClarksviUe, 
  Tenn. 
  

  

  14. 
  JVIaple-leaf, 
  Quadrula 
  lachrymosa 
  (Lea). 
  — 
  Lachrymosa, 
  while 
  

   not 
  common, 
  occurs 
  in 
  small 
  numbers 
  in 
  practically 
  all 
  the 
  mussel 
  

   beds 
  of 
  the 
  river. 
  Some 
  examples 
  of 
  this 
  shell 
  found 
  with 
  projecting 
  

   tubercules, 
  appear 
  to 
  be 
  the 
  form 
  described 
  as 
  asperrima, 
  now 
  a 
  

   synonym. 
  This 
  shell 
  has 
  good 
  luster 
  and 
  size 
  in 
  the 
  Ilhnois 
  and 
  is 
  

   usually 
  classed 
  as 
  first-grade 
  material. 
  One 
  example 
  found 
  in 
  the 
  

   Spoon 
  River 
  measured 
  4^ 
  inches 
  in 
  length. 
  

  

  15. 
  MoNKEY-FACE, 
  Quadrula 
  metanevra 
  (Rafmesque). 
  — 
  A 
  rare 
  

   species 
  in 
  the 
  lUinois, 
  but 
  few 
  specimens 
  being 
  found 
  at 
  the 
  stations 
  

   given 
  in 
  the 
  general 
  table 
  on 
  page 
  37. 
  

  

  The 
  green 
  triangular 
  markings 
  so 
  prominent 
  in 
  well-defined 
  species 
  

   are 
  faint 
  in 
  our 
  specimens. 
  Some 
  examples 
  vary 
  considerably 
  in 
  

   shape 
  and 
  general 
  appearance. 
  One 
  is 
  heavily 
  pustulose 
  anteriorly, 
  

   many 
  of 
  the 
  pustules 
  being 
  elongate 
  along 
  the 
  Hnes 
  of 
  growth, 
  and 
  

   is 
  strongly 
  suggestive 
  of 
  Q. 
  pustulosa. 
  Another 
  of 
  our 
  examples 
  has 
  

   the 
  markedly 
  ])inched 
  posterior 
  dorsal 
  portion 
  generally 
  pronounced 
  

   in 
  this 
  species 
  in 
  the 
  lower 
  Wabash. 
  All 
  of 
  our 
  shells 
  are 
  noticeably 
  

   inflated. 
  

  

  16. 
  Washboard, 
  Quadrula 
  heros 
  (Say). 
  — 
  Ileros 
  is 
  tlie 
  best 
  button 
  

   shell 
  of 
  the 
  Ilhnois 
  and 
  produces 
  the 
  most 
  blanks 
  per 
  ton, 
  but 
  in 
  

   some 
  locahties 
  is 
  porous 
  and 
  does 
  not 
  do 
  well 
  for 
  an 
  engraved 
  but- 
  

   ton. 
  The 
  three-ridge 
  type 
  makes 
  a 
  better 
  finislied 
  button. 
  In 
  the 
  

   upper 
  stretches 
  of 
  the 
  river 
  the 
  complete 
  washboard 
  shell 
  averages 
  

   about 
  1 
  pound 
  in 
  weight 
  and 
  is 
  frequently 
  spotted; 
  but 
  from 
  below 
  

   Beardstown 
  to 
  Twelvemile 
  Island 
  it 
  is 
  much 
  smaller, 
  flatter, 
  freer 
  

   from 
  spots 
  and 
  stains, 
  and 
  of 
  good 
  luster. 
  At 
  Hardin 
  tliis 
  shell 
  is 
  

   no 
  larger 
  than 
  tlie 
  undulata 
  or 
  bluepoint 
  of 
  Peoria 
  Lake, 
  even 
  old 
  

   examples 
  called 
  "bald-pates" 
  found 
  in 
  tlie 
  channel 
  are 
  small. 
  

  

  