﻿10 
  

  

  GROWTH 
  AND 
  MIGRATION 
  OF 
  FRESH-WATER 
  MUSSELS. 
  

  

  mentioned 
  above; 
  and, 
  further, 
  some 
  were 
  lost 
  to 
  the 
  small 
  boy 
  inter- 
  

   ested 
  in 
  collecting 
  brass 
  tags. 
  

  

  On 
  the 
  whole, 
  however, 
  the 
  specimens 
  were 
  reclaimed 
  in 
  such 
  large 
  

   numbers 
  that 
  all 
  of 
  the 
  material 
  could 
  not 
  be 
  worked 
  over 
  for 
  records 
  

   in 
  the 
  time 
  available 
  when 
  the 
  rechecking 
  and 
  reclaiming 
  was 
  done. 
  

  

  In 
  rechecking 
  material 
  as 
  many 
  specimens 
  were 
  handled 
  as 
  time 
  

   would 
  permit. 
  As 
  small 
  specimens 
  were 
  few 
  in 
  number, 
  these 
  were 
  

   always 
  rechecked 
  and 
  care 
  was 
  taken 
  to 
  include 
  representatives 
  of 
  all 
  

   species. 
  Aside 
  from 
  these 
  influences 
  in 
  selection, 
  specimens 
  were 
  

   rechecked 
  as 
  found. 
  The 
  left-over 
  material 
  was 
  returned 
  to 
  the 
  

   stream 
  when 
  it 
  could 
  not 
  be 
  handled. 
  Where 
  a 
  lot 
  was 
  checked 
  over 
  

   several 
  times, 
  as 
  lot 
  F, 
  naturally 
  the 
  ones 
  worked 
  over 
  the 
  fu-st 
  time 
  

   they 
  were 
  reclaimed, 
  September 
  26, 
  1910, 
  were 
  again 
  followed 
  up 
  in 
  

   subsequent 
  work. 
  

  

  Far 
  more 
  data 
  were 
  gathered 
  than 
  can 
  be 
  included 
  in 
  this 
  paper. 
  

   In 
  the 
  tables 
  given 
  below 
  I 
  have 
  stated 
  the 
  reasons 
  for 
  selecting 
  the 
  

   data 
  presented. 
  Nearly 
  all 
  the 
  material 
  used 
  is 
  selected 
  from 
  lots 
  

   D 
  and 
  F, 
  as 
  the 
  latter 
  was 
  more 
  available 
  for 
  frequent 
  recheckings, 
  

   and 
  lot 
  D 
  of 
  the 
  Shoofly 
  material 
  represented 
  a 
  larger 
  number 
  of 
  

   species 
  and 
  more 
  range 
  as 
  to 
  size. 
  

  

  Table 
  1. 
  — 
  A 
  Year's 
  Growth 
  in 
  Young 
  Quadrul.e 
  from 
  Lot 
  D. 
  

   [Note. 
  — 
  All 
  starred 
  numbers 
  in 
  tables 
  represent 
  specimens 
  shown 
  in 
  plate 
  figures.] 
  

  

  avekage 
  gain 
  and 
  per 
  cent 
  of 
  aggregate 
  gain 
  for 
  each 
  species. 
  

  

  o 
  Specimens 
  listed 
  in 
  all 
  tables 
  according 
  to 
  size 
  for 
  each 
  species. 
  

  

  