﻿24 
  GROWTH 
  AND 
  MIGRATION 
  OF 
  FRESH-WATER 
  MUSSELS. 
  

  

  Specimens 
  149 
  and 
  158, 
  Quadrula 
  lachrymosa 
  (table 
  1 
  and 
  as 
  shown 
  here 
  about 
  two- 
  

   thirds 
  natural 
  size). 
  These 
  specimens 
  are 
  from 
  the 
  Shoofly, 
  the 
  two 
  lachrymosa 
  above 
  

   from 
  the 
  Chikaskia. 
  The 
  -rest 
  rings 
  are 
  about 
  the 
  same 
  as 
  413 
  and 
  the 
  time 
  (June, 
  

   1910, 
  to 
  June, 
  1911) 
  is 
  the 
  same. 
  

  

  Specimen 
  158 
  is 
  the 
  left 
  valve 
  and 
  so 
  does 
  not 
  show 
  the 
  tag 
  or 
  mark. 
  

  

  Plate 
  III. 
  

  

  Specimen 
  566, 
  Lampsilis 
  anodontoides 
  (table 
  8) 
  , 
  shows 
  5 
  mm. 
  increase 
  in 
  length 
  in 
  

   nearly 
  three 
  months 
  (June 
  27, 
  1910, 
  to 
  Sept. 
  19, 
  1910). 
  A 
  mature 
  Chikaskia 
  speci- 
  

   men 
  growing 
  in 
  rather 
  unfavorable 
  environment. 
  

  

  Specimen 
  763, 
  Quadrula 
  lachrymosa, 
  shows 
  how 
  the 
  tag 
  wire 
  is 
  overlaid 
  with 
  nacre 
  

   {t) 
  nearly 
  three 
  months 
  after 
  tagging 
  (June 
  27, 
  1910, 
  to 
  Sept. 
  19, 
  1910). 
  

  

  Specimen 
  200, 
  Quadrula 
  undulata. 
  In 
  the 
  Shoofly 
  (p. 
  7) 
  no 
  Q. 
  undulata 
  under 
  

   193 
  grams 
  was 
  found 
  in 
  June, 
  1910. 
  In 
  1911 
  two 
  specimens 
  were 
  secured 
  that 
  may 
  

   be 
  called 
  young. 
  No. 
  200 
  is 
  one 
  of 
  these 
  and 
  is 
  interesting 
  on 
  account 
  of 
  the 
  regu- 
  

   larity 
  of 
  rest 
  rings, 
  four 
  in 
  number. 
  The 
  specimen 
  measures 
  80 
  mm. 
  in 
  length 
  and, 
  

   according 
  to 
  estima.tes 
  worked 
  out 
  upon 
  knoTSTi 
  growth 
  of 
  this 
  species 
  in 
  the 
  Shoofly, 
  

   was 
  4 
  or 
  5 
  years 
  old 
  when 
  taken 
  (p. 
  14). 
  

  

  